Sdar journal 2015

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Journal

Sustainable Design & Applied Research in Engineering and the Built Environment November 2015 Issue 5

The Journal of Applied Research in Innovative Engineering and the Built Environment

School of Multidisciplinary Technologies Engineering and the Built Environment

Building Servicesnews

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Institiúd Teicneolaíochta Átha Cliath Dublin Institute of Technology

School of Electrical and Electronic Engineering The School of Electrical and Electronic Engineering, Dublin Institute of Technology (SEEE), is the largest education provider in the electrical and electronic engineering space in Ireland in terms of programme diversity (apprentice to PhD), staff and student numbers.

Based in Dublin city centre (Kevin Street) and established since 1887, it prides itself in providing practice-based and professionally-accredited programmes across a variety of full-time and parttime options.

The School also focuses on applied research with a strong emphasis on producing useful and novel ideas to help Irish industry compete globally. SEEE research is recognised for its impact and quality, which in many cases is on a par with that of the very best groups internationally.

SEEE Programmes Level 9 (Masters) MSc – Energy Management

DT711 or DT015

ME – Sustainable Electrical Energy Systems

DT704 or DT705

MSc in Electronic and Communications Engineering

DT085 or DT086

Level 8 (Hons) BE in Electrical and Electronic Engineering

DT021

BE in Computer and Communications Engineering

DT081

BSc in Electrical Services and Energy Management

DT712 or DT018

BSc Networking Applications and Services

DT080B

Level 7 BEngTech and Communications BEngTech in in Electronic Electrical Services Engineering Engineering

DT008

BEngTech in Electrical and Control Engineering

DT009

BEngTech in Sustainable Design for Electrical Services Engineering

DT010

BTech in Networking Technologies

For further information on the school contact: School of Electrical and Electronic Engineering, Dublin Institute of Technology, Kevin Street, Dublin 8 Tel: + 353 1 402 4617/4650/4575 Email: seee.admin@dit.ie www.dit.ie/colleges/collegeofengineeringbuiltenvironment

DT080A

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Contents

Introduction

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Editor’s foreword

Welcome to the fifth edition of the SDAR Journal which the Chartered

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A reader’s guide to this issue

Institution of Building Services Engineers (CIBSE) produces in partnership with the Dublin Institute of Technology (DIT).

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Validating the performance of a prototype phase change material for a thermal energy storage tank, connected to micro-CHP

CIBSE partners with DIT throughout the year on Continuous Professional Development (CPD) events. We feel it is essential to have strong relationships with educational bodies such as DIT, and the SDAR Journal is a showcase for this ongoing relationship.

Dr Michael McKeever

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Evaluation of building performance in use – a case study of the Seager Distillery development Michael CN Lim, David Ross, Steve Harper

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First steps in developing cement-based batteries to power cathodic protection of embedded steel in concrete Dr Niall Holmes, Dr Aimee Byrne, Professor Brian Norton

33

CIBSE Ireland represents circa 800 members, the majority of whom are graduate and student members. In co-publishing the SDAR Journal with DIT we play a proactive role in supporting them, and in promoting research to help sustain the future of the engineering sector as a whole.

It is encouraging to see strong educational and research papers being presented, and it instils confidence in the sector going forward as the economic indicators continue to be positive.

I would encourage all in research and academia to review the papers in this year’s SDAR Journal and to consider their own research and studies with a view to publication in the next edition.

The lighting of St Mel’s Cathedral Mark Reilly

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The Pavilion of Light, Mardyke Gardens, Fitzgerald Park, Cork Stephen Robinson

The SDAR Journal is a sustainable design and applied research publication written by engineers and researchers for professionals in the built environment. It is edited by staff of the Dublin Institute of Technology.

David Doherty

Editor: Dr Kevin Kelly, DIT and CIBSE Contact: kevin.kelly@dit.ie

As Director and Dean of the College of Engineering and Built Environment at DIT I am delighted to welcome the fifth edition of the SDAR Journal.

Deputy Editor: Dr Keith Sunderland, Head of Electrical Services Engineering, DIT Contact: keith.sunderland@dit.ie

This journal is an excellent example of academia working closely with industry to support good-quality applied research that has a genuinely useful impact. This helps DIT as an institution to fulfill a core objective of our mission which is to build strong and lasting relationships with industry and to disseminate new knowledge and ideas as widely as possible. It also offers practicing engineers an opportunity to publish in collaboration with experienced academics.

Editorial Team: Yvonne Desmond, Pat Lehane, Kevin Gaughan The Reviewing Panel is: Dr Martin Barrett, Professor Michael Conlon, Professor Tim Dwyer, Dr Avril Behan, Ciara Aherne, Kevin Gaughan, David Doherty, Dr Marek Rebow, Professor David Kennedy and Professor Gerald Farrell Upload papers and access articles online: http://arrow.dit.ie/sdar/ Published by: CIBSE Ireland and the College of Engineering & Built Environment, DIT Produced by: Pressline Ltd, Carraig Court, George’s Avenue, Blackrock, Co Dublin. Tel: 01 - 288 5001/2/3. email: pat@pressline.ie Printed by: Swift Print Solutions (SPS) ISSN 2009-549X © SDAR Research Journal Additional copies can be purchased for €50

Chairman, CIBSE Ireland

Applied research in DIT is recognised for its impact and quality, and in many cases is on a par with that of the very best groups internationally. DIT is in the top 3% of universities worldwide and as a college we have a strong emphasis on research in areas such as energy management, renewable energy technologies, electrical energy systems and sustainable design in the built environment. These research areas are of vital importance as Ireland faces future challenges in areas such as sustainability and energy supply.

In closing I want to congratulate the editorial team and all the authors on the high quality of their work and on their contributions to research in this area, both in Ireland and worldwide.

Professor Gerald Farrell Director and Dean of the College of Engineering and Built Environment, DIT

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SDAR Journal 2015

Editor’s foreword This is the fifth edition of the SDAR Journal and all 25 papers are now available online at: http://arrow.dit.ie/sdar/ Presently we publish five papers in one edition annually but we are considering extending to more papers in 2016. The SDAR Journal is coming in for very favourable comment, both in Ireland and internationally, and you will see if you open the link above that there have been 12,000 downloads of papers from over 100 countries worldwide. Presumably, you are currently reading a hardcopy printed edition and you may be interested to know that we have also distributed 10,000 paper copies to industry and academia throughout Ireland.

The intention of the SDAR Journal is to encourage the publication of insightful evidence-based findings from innovative practice in low-energy design of the built environment. Industry engineers who submit their work can rely on us to assist by offering free support and peer review processes supported by experienced authors and academics. SDAR Journal papers come from a combination of experienced authors, practicing engineers and researchers.

However, many of our authors have not previously published in a scholarly journal and so we consciously act as an entry point for working engineers and inexperienced researchers.

To publish, we demand critical reflection and objective evaluation of real-world projects, but we help authors achieve this. I would encourage every company to implement applied research in their companies through post-occupancy evaluations and similar evaluation. If you are doing this already, then consider submitting short abstracts of proposed papers to us so that we might engage with you to help bring these ideas to fruition through publication of the findings. Such publications help leading companies add value to their work by evidencing claims through a rigorous (and free) peer-review process.

Would-be contributors are also encouraged to submit abstracts for the annual SDAR Awards and Irish Lighter competitions. This issue carries two papers from this year’s SDAR Awards and two papers from the Irish Lighter competition. The final paper is derived from a presentation at the CIBSE/ASHRAE annual conference.

Editorial Board Professor Brian Norton, Dublin Institute of Technology Professor Andy Ford, London South Bank University Professor Tim Dwyer, University College London Dr Hywel Davies, CIBSE Mr David Doherty, Chairman,CIBSE Ireland Professor Gerald Farrell, Dublin Institute of Technology Professor John Mardaljevic, Loughborough University Professor Michael Conlon, Dublin Institute of Technology

Dr Kevin T. Kelly C Eng FCIBSE FSLL FIEI Head of School of Multidisciplinary Technologies Dublin Institute of Technology Past President Society of Light & Lighting Kevin.kelly@dit.ie

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Professor David Kennedy, Dublin Institute of Technology Dr Kevin Kelly, Dublin Institute of Technology, CIBSE, SLL

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A Reader’s Gude

A Reader’s Guide In this issue we have five papers — one on energy storage, another on post-occupancy evaluation from the UK and a third on making cathodic protection of concrete more sustainable. The other two papers are on lighting, a topic that is presently the most downloaded online from the SDAR Journal.

The first paper addresses the challenge of storing energy more efficiently. This research builds and tests an innovative phase change material, the thermal energy storage unit (PCM-TES), that was invented at DIT’s Dublin Energy Lab and installed in an office building in Cork in 2014. The PCM-TES is connected to a microCHP unit and also addresses the problem of what to do with waste heat from a combined heat and power unit at evening peak tariff periods, when the building heating loads are lowest.

The research is carried out using a 2000-litre water tank and a 2000-litre PCM-TES unit and comparing both storage systems.

Test results prove that the PCM-TES stores 6.5 times more heat for the same plantroom footprint, allowing the CHP unit to run continuously during peak periods. The stored energy is then used to pre-heat the building early in the morning. This allows CHP thermal demand to align better with the electrical tariff, reduce utility bills and eliminate the need for back-up boilers.

The research for the third paper investigates the first steps in developing innovative cement-based batteries to power cathodic protection in reinforced concrete structures. Cathodic protection is a well-used method to protect embedded steel in concrete but research into more sustainable alternatives to supply the external electrical supply has not received much attention to date. This research focuses on developing cement-based batteries which increases the ionic conductivity of the solution in the cement pores, how best to seal the batteries from moisture loss and comparing different electrode materials and treatments.

The preliminary findings demonstrate that cement-based batteries can sustainably produce sufficient electrical outputs for cathodic protection by using the correct materials and arrangement of castin anodes and cathodes.

The second paper is a two-year post-occupancy performance evaluation of a new high-density development in London. Three apartments were studied in detail whereby the building fabric, MVHR units and the communal heating system were evaluated by comparing actual performance against design intent.

The fourth paper focuses on the design and methodology of an interesting lighting installation at the re-constructed St Mel’s Cathedral in Longford, Ireland. Restored after a catastrophic fire in 2009, a lighting scheme using modern LEDs and intelligent lighting controls is used to recreate the historic atmosphere of this significant building. The project posed particular problems and the way they are addressed is insightful in that it moves away from standard lighting practice using horizontal illuminance as the main emphasis, to a more tailored methodology focused on real user need, producing an appropriate atmosphere in this building that emphasises visual quality.

The study findings highlight the gaps in expected performance. The building fabric has been shown to perform well but some issues have been identified with the performance of the MVHR systems. The study also summarises the lessons learnt, which informs the delivery of future developments and highlights areas for improvement in terms of design, installation, commissioning and post-occupancy maintenance.

The final paper is from an engineer who does not rely on standard practice but works much more intuitively to provide a more artistic outcome and a stunning visual effect. This is a unique project posing artistic and many practical challenges with respect to local fauna and wildlife. The former were dealt with intuitively and the latter by using sound engineering evaluation.

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AWARDS

2016

Call for Abstracts Short abstracts (between 100/200 words max) for entry into the SDAR Awards 2016 must be submitted

by Monday, 14 December 2015, by email directly to Michael McDonald and/or Kevin Kelly of DIT at michael.mcdonald@dit.ie and kevin.kelly@dit.ie The SDAR Awards is a joint initiative between CIBSE Ireland and DIT, supported by Building Services News, and sponsored by John Sisk & Son. The awards are unique in that they are intended to disseminate knowledge, encourage research in sustainable design of the built environment and raise the quality of innovation and evaluation of such projects. Entries are required to critically evaluate real life data, and examine both successes and challenges within leading-edge

projects throughout Ireland or further afield. This competition is open to architects, engineers and all professionals involved in construction projects.

Now more than ever as positive signs ripple through the built environment, this unique synergy between industry and academia allows greater potential for integration of modern low-carbon technologies and low-energy design methodologies.

The SDAR Awards competition is intended to create a platform for the growth of applied research in the expanding green economy. Post occupancy evaluations and similar critical appraisal of low-energy projects facilitate the transition from ideologically-driven innovations, sometimes offering poor value, to evidence-based applied research

http://arrow.dit.ie/sdar/

that proves value or identifies weaknesses that the industry can learn from. These successes and failures help inform the professional community across all the building industry disciplines.

From the abstracts submitted by the Monday, 14 December 2015 deadline, a shortlist will be selected by peer review, and those selected will be invited to prepare final papers by 1 February 2016.

First prize is a cheque for €1000.

Candidates that present at the awards also have a chance of publishing their papers in the SDAR Journal – arrow.dit.ie/sdar/ Next year’s final will take place in March 2016 in DIT, Bolton Street.

For further information contact: michael.mcdonald@dit.ie or kevin.kelly@dit.ie

Sponsored by :

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SDAR AWARD WINNER 2015

Validating the performance of a prototype phase change material for a thermal energy storage tank, connected to a micro-CHP

Dr Michael Mc Keever SCHOOL OF ELECTRICAL AND ELECTRONIC ENGINEERING DUBLIN INSTITUTE OF TECHNOLOGY mick.mckeever@dit.ie

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SDAR Journal 2015

Abstract This paper describes the performance testing of a 2000-litre phase change material used in a Thermal Energy Storage (PCM-TES) demonstrator unit invented in DIT’s Dublin Energy Lab and installed in an office building in Cork in 2014. The PCM-TES is connected to a Micro-CHP unit and stores waste heat from the CHP at evening peak tariff periods when the building heating loads are lowest. The CHP is also connected to a 2000-litre water tank allowing direct comparison of the energy storage capacities and performances of both storage systems. Charging results presented show that the PCM-TES holds 6.5 times more heat for the same plant room footprint, allowing the CHP to run continuously during peak periods and producing a better overall electrical/ thermal efficiency. Discharging results show how the PCM-TES stored energy can be used to pre-heat the building heating system early in the morning, shifting CHP thermal demand to align better with the day rate electrical tariff period. The PCM-TES eliminates the need for back-up gas boilers to be used for the early morning heat demand peak. A discussion of PCM-TES benefits over a water-based TES is supported and presented here.

Key words: Phase change materials, latent heat storage, thermal storage and CHP

Glossary: PCM Phase change material TES Thermal energy store CHP Combined heat and power NPV Net present value SPP Simple payback period ROI Return on investment

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1. Introduction Identifying the economic advantages of installing micro-CHP in buildings requires a techno-economic analysis over the full life-cycle of the system. Financial decision makers have to be convinced that a proposed plant room installation has a reasonable payback and is a sustainable acceptable risk investment. This argument can be made using estimated up-front capital costs, running costs and disposal costs, in calculation of Net Present Value (NPV), Simple Payback Period (SPP) or Return on Investment (ROI) analysis. The most difficult costs to predict are the fuel consumption and maintenance costs of running the equipment over its lifespan.

Techno-economic results are always compared to other benchmark technology solutions on the market. In retrofitting, the availability of plant room space and the footprint of the equipment must not be overlooked.

The argument for CHP is that the electrical power can be exported at a profit, but this only makes economic sense if the heat can be used directly or stored for later use. The heat energy needs to be used to make CHP a viable and sustainable solution. This requires storage as the heat demand profiles do not necessarily coincide with high electric tariff periods. Thermal energy storage allows the CHP to export electrical power at peak electrical demand periods and to release heat when building thermal demands are high during low electrical tariff periods. This has traditionally been implemented using Sensible Heat Thermal Energy Store (SH-TES) water tanks that store energy by raising the temperature of water inside the tank. This solution is low risk and the benchmark used to compare thermal energy storage solutions. However, these SH-TES units are large, often occupying significant plant room floor space or, if very large, they may require planning permission when installed outside the building.

A new 500-litre Phase Change Materials Thermal Energy Store (PCM-TES) was developed at the Dublin Institute of Technology.

The PCM-TES was designed to store six times the energy storage capacity of a SH-TES operating on a 5°C differential temperature.

A building heated by a micro-CHP with a 2000-litre SH-TES was selected as an ideal demonstration site. A 2000-litre PCM-TES (4 x 500-litre) was retrofitted in parallel to the 2000-litre SH-TES to enable comparative testing of both energy stores. The objective was to produce data suitable for a techno-economic analysis of the PCM-TES system.

2. Background PCM is a material that absorbs latent energy as heat when it melts and releases this latent heat back when solidifying(1)(2). The temperature of melting and solidifying are separated by a few degrees and high quantities of heat can be stored over small differential temperatures (Delta-T)(3). An example of this is a 1kg of RT70HC wax(4) which melts and solidifies in the temperature range 69°C to 71°C and stores 64Wh/kg. A corresponding 1kg of water over the same temperature range stores only 2.3Wh/kg. In practice, the energy storage density ratio between PCM and water is lower(5). If the operating temperature range was increased to 66°C

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to 71°C, the energy density ratio would drop to around 9:1 when comparing PCM to water on a volumetric basis.

PCM absorbs heat more slowly than water and large blocks of PCM do not have the dynamic response times required by building heating systems to meet load fluctuations. The thermal conductivity of wax-based PCM is 0.2W/mK compared to 0.58W/mK for water.

Charging and discharging response times are proportional to the ratio of the PCM volume to surface area(6).

The low thermal conductivity problem with PCM can be overcome by distributing the heat source and heat sink inside the PCM using pipes, fins and plates. This increases the heat transfer rates by increasing the heat exchange surface area but, as a consequence, it reduces the quantity of PCM for a fixed volume. A significant PCM-TES design challenge is to find the correct compromise between energy storage density and heat response rates to meet heat demand peaks and troughs(7).

This research set out to develop and evaluate a novel PCM-TES design for use in buildings. The PCM-TES demonstrator unit is installed in the CIT Nimbus building plant room and coupled to a micro-CHP unit(8). The focus of this paper is not on the internal design of the PCM-TES unit but on a comparative study of the performance of this system compared to an identical sized water tank operating in a live building. The test results on the PCM-TES unit are presented to validate the system design concept and performance when coupled to a micro-CHP.

3. The PCM-TES demonstrator tank The PCM-TES prototype uses four 500-litre metallic tanks, each with two suitably-shaped hydraulic coils and inner space filled with PCM. A picture of one tank is shown in Figure 1 with the lid partially removed, revealing the internal PCM and two heat transfer coils. The inlet piping of the system at the front shows the piping terminals for each coil.

Figure 2: PCM-TES installation during commissioning (only top unit shown insulated).

simultaneously or independently as required by the CHP controller and BMS system. The thermal storage capacity of a 500-litre unit is 29kWh for a delta-T of 5°C across the primary coil. The PCM used in this demonstrator is a wax-based commercial PCM that is non-corrosive and has a life of over 10,000 solid-liquid charging cycles. Unlike salt-hydrate PCM materials, wax PCM does not suffer from under-cooling, or permanent material segregation, and has a pH close to 7(9). The four unit demonstrator is shown in Figure 2.

This gives a total capacity of 126 kWh of storage for a delta-T of 20°C across each unit connected in series. Two PCM materials are used. The top unit is filled with a PCM with a melt temperature in the range 80°C to 82°C, while the other three units are filled with a PCM that melts in the range 68°C to 70°C. The 2000-litre PCM-TES allows direct comparison between the PCM-TES technology and the 2000-litre SH-TES installed as part of the original plant room CHP installation.

Figure 1: Prototype 500-litre PCM-TES unit.

The PCM-TES unit operates as follows in the demonstrator. The primary coil is used to supply thermal output from the micro-CHP into the PCM-TES. The PCM-TES unit discharges its energy through the secondary coil. This allows the primary and secondary circuits to be operated separately so the unit may charge and discharge

4. The demonstrator site installation and operation The Micro-CHP unit is a natural gas-fired Sokratherm GG50 with a 90°C/70°C thermal circuit(10). The CHP installation is controlled by a PLC-based SCADA system allowing set point control of both thermal and electrical outputs.

The SCADA system has full integration with the BMS system that

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SDAR Journal 2015

Water

PCM tanks

CHP

thermal load on the return manifold causes the gas fired boilers to both activate and complement the CHP. When temperatures stabilise, the CHP operates alone and supplies heat to the building.

When the thermal demand drops, the CHP charges the SH-TES and shuts down when the SH-TES exceeds 85°C. The CHP kicks in again when tank temperatures drop below 74°C. During peak tariff periods the CHP exports electrical power. However, the heat demand of the building is low at this time and excess heat is dumped to air to prevent the CHP tripping out on high return temperature.

The retrofitting of the PCM-TES to the CHP was carried out to produce real building data to answer three key research questions:

Figure 3: Plant room showing the CHP, PCM tanks and sensible water tank.

controls the energy requirements of the building. The initial plant room design incorporated a 2000-litre Sensible Heat Thermal Energy Storage tank (SH-TES). Figure 3 shows the SH-TES (red and white in the background), the CHP unit and the PCM tank during its commissioning. A simplified process schematic of the heating system is shown in Figure 4 for the PCM tank only. The sensible tank operates in parallel with the PCM tank connections (not shown in Figure 4). The CHP-PCM-TES heating circuit system consists of two parts, the primary charging loop operating on a 90°C/70°C supply heat from the CHP and return line operating on a 70°C/50°C loop. The thermal output of the CHP is controlled by varying flow through the VSD pump (P01) to maintain a 90°C CHP output temperature. The CHP trips out if the return temperature exceeds 75°C for a period of time.

The secondary side of the PCM-TES is connected to the building system header and return pipework. This is controlled by a variable speed pump (P02) drawing water from the return manifold which is heated in the PCM tank before discharge into the building heating header manifold.

The heating system also includes two back-up gas-fired boilers which are activated if the header return temperature drops below 62.5°C. Gas consumption of the boilers in the morning was in the region of 70kWh during the heating season.

The heating system operates as follows under BMS control. At 7am the BMS calls for heat and the CHP starts. Normally the large

Figure 4: Process and instrumentation drawing for the PCM tank demonstrator site.

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1. How much energy could the PCM-TES store when operating in a real building driven by a micro-CHP? 2. How long could the PCM-TES extend the operation of the CHP without dumping heat to air?

3. What percentage of the operation of the gas fired boilers could be eliminated in the morning by discharging the PCMTES prior to 7am?

Validating the performance of the prototype PCM-TES tank connected to a Micro-CHP is essential to demonstrating system performance. This provides data to allow cost benefit analysis of PCM-TES for other installations.

5. Results The testing scenario for the PCM-TES and SH-TES was identical.

The CHP thermal output was used to charge one tank at a time, with no heat being delivered to the building during charging. This helped to make the PCM-TES and SH-TES tests comparable by removing the variable building loads affecting test results. As a consequence, the CHP outputs were turned down to 50% operation to replicate the normal charging process with the building load taking the other 50% output. CHP thermal output in the range 20kW to 25kW thermal and electrical output varied between 20kW to 30kW. During the discharging both systems were allowed to discharge their energy into the building manifold under the same conditions.

This occurred when the manifold return temperature was 60°C.

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6. CPH thermal operation during charging The first test conducted was the charging of the SH-TES as shown in Figure 5. The heating control system kicks in when the top temperature of the SH-TES drops below 75°C. Stratification in the tank can clearly be seen as the bottom temperature in the tank is 55°C. The charging takes 17 minutes and the total energy stored by the SH-TES is 13.5kWh over this period. The CHP stops when the upper temperature limit of the top temperature is exceeded at 86°C. It should be noted that the lowest temperature in the SH-TES is 73°C, showing large temperature stratification within the tank.

This is significant when discharging the tank into the header as the return temperature is below the 60°C set point start of the boilers.

Temperature Rise °C 60 to 85

PCM Energy Stored kWh

CHP Run Time (mins)

89.95

200

Table 1: Energy stored by PCM during charging from 60C to 85C.

Comparing the energy storage densities over the operating range of the building heating system, the PCM-TES holds 6.56 times more heat energy.

7. CHP electrical operation during charging The significance of charging times and storage density has a direct influence on the electrical operation of the CHP. When testing the CHP power output, both storage units were charged from ambient temperature to full operating temperature. When the SH-TES was fully charged, the unit was discharged directly into the building to allow the CHP recharge the tank a number of times as shown in Figure 7. Significantly, the SH-TES was charged three times in the same period it took to charge the PCM-TES from ambient.

However, this represents three starts for the CHP whereas the CHP runs continuously when charging the PCM-TES.

Figure 5: Single charge of the SH-TES from 75°C to 85°C.

During early morning heating of the building, the PCM-TES is allowed to discharge to below 60°C into the header manifold which is the cut-in set-point for the back-up boilers. In this set-up it takes 200 minutes to fully charge the PCM-TES as can be seen in Figure 6.

Figure 7: CHP electrical output when charging the PCM-TES and SH-TES from fully cold.

The electrical output totals are shown in Table 2. The CHP runs continuously as the PCM-TES charges. Compare this to the SH-TES which charges from cold three times faster than the PCM-TES but as a consequence the electrical outputs are far lower over the first 150 minutes. The SH-TES is discharged twice in order to compare the total possible CHP operation over a single charge time of the PCM-TES. Figure 6: Single charge of the PCM-TES from 60°C to 85°C.

Energy total stored by the PCM store is shown in Table 1 for a full charge cycle of the PCM-TES between 60°C and 85°C which is defined by the BMS control system. The PCM inside all the units heat above their melt temperatures and the control system shuts down the CHP when the highest temperature reaches 85°C.

Average PCM-TES charging Electrical Output kWe

103

Average SH-TES charging Electrical Output kWe

61

Table 2: The average electrical output during charging of the thermal storage units.

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SDAR Journal 2015

8. Discharging performance conparison of the PCM-TES The results presented in this section show the SH-TES and PCMTES discharging characteristics when feeding the building heating manifold early morning prior to the CHP starting at 7am. Normally when the CHP starts, the back-up gas boilers activate as there is a large demand due to all the cold liquid in radiators and piping in the building overnight. Figure 8 shows the operation of the gas boilers.

The PCM-TES discharge is shown in Figure 10. The discharge in this case takes 50 minutes to reach 70째C from a fully charged state.

The time to discharge is a combination of the 6.5 times higher energy density and the lower rate of release of energy from the PCM material.

Figure 10: Discharge characteristic for the PCM-TES.

Figure 8: Gas boiler heat curves when assisting the CHP early in the morning.

The total additional energy used by the boilers which is derived from gas is calculated from Figure 8 and shown in Table 3.

Boiler 1 kWh

Boiler 2 kWh

Total kWh

37.93519

29.70833

67.64352

Table 3: Gas energy consumed by the backup gas boilers without the PCMTES fitted.

The minimum requirement for any thermal storage device installed in the current building must be above 67.64kWh if the boiler gas costs are to be eliminated. The current 2000 litre SH-TES only stores 13.4 kWh. If the energy was stored in a water tank for the operating differential temperatures of the heating system, the 10000-litre tank would be required. The discharge curve for the 2000-litre SH-TES is shown in Figure 9. The discharge only takes eight minutes due to a combination of the low level of energy stored and the rate at which the stored energy can be released.

This longer discharge time of the PCM-TES can be compensated for by programming the SCADA/BMS system to discharge the PCM-TES 50 minutes before the CHP starts at 7am. The only reason the CHP starts at 7am is due to the economics of the feed-in tariff periods. The boilers never kicked in when the PCM-TES discharges early morning. The PCM-TES and CHP working together never cause the header return temperatures to drop below the activation set-point temperatures of Boiler 1 or Boiler 2 after 7am. Using the data in Table 3, a saving of 67.64 kWh of gas per heating day is achieved by allowing the PCM-TES to discharge and eliminate the need to use the backup boilers.

9. Discussion The charging and discharging results show that the PCM-TES holds 6.5 times the heat energy of a SH-TES water tank of identical volume when connected to this CHP operating on a 90/70째C heating system. The advantages of the PCM-TES are that it allows the CHP to run longer when there is no heat demand in the building. This normally coincides with the peak tariff period in the evening which is exactly when commercial building workers leave to go home at the end of their working day. The heat energy is stored overnight and used to pre-heat the building heating system in preparation for when the CHP operates early the following day.

This results in the building being at the correct temperature when the workers enter the building at the start of their working day.

Referring back to the economic advantages of installing a PCMTES, there are three findings made using data generated for the demonstrator PCM-TES. The first relates to the need for two back-up gas fired boilers. This could be reduced to one single boiler, used primarily when the CHP is being serviced. This represents a capital expenditure saving, a gas saving and an annual maintenance saving.

Figure 9: Discharge characteristic for the SH-TES.

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The second relates to the plant floor space being saved by having one PCM-TES. Five to six water tanks would be required in the demonstrator site to hold the energy of the PCM-TES. Indeed, the

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Validating the performance of a prototype phase change material for a thermal energy storage tank, connected to a micro-CHP

space saved by having only one backup boiler increases this figure further.

The third relates to the overall electrical performance during peak tariff periods. The PCM-TES allows the generator to run continuously during evening peak tariff windows, maximising the revenues generated for power export, especially as the building occupancy is normally low at the end of the working day.

10. Conclusion This paper presents real building performance data for a novel design PCM-TES. The PCM-TES has been installed in a commercial building and its operation is compared to a SH-TES of the same size. Results show the PCM-TES holds 6.5 times more heat, allows the CHP to run longer at peak tariffs and has the capacity to eliminate one of the backup gas boilers, saving on CapEx and gas energy consumption when compared to the SH-TES. It is concluded that the demonstration of a 6.5:1 energy density ratio for the same plant room space represents a viable proposition for heating system design engineers.

The current technology is now being designed to reduce the embodied energies by considering alternative materials to the stainless steel and using bio-degradable PCM materials which will influence the life-cycle costs and sustainability of this novel thermal energy storage technology.

References [1] S. McCormack, P. Griffiths. Phase Change Materials – A Primer for Architects and Engineers (20120 –ISBN 978-1-85923-260-6.

[2] L.F. Cabeza, Heat and Cold Storage with PCM (2013). ISBN 9783-540-68556-2.

[3] A. de Gracia, L. F. Cabeza, Phase change materials and thermal energy storage for buildings, Energy and Buildings, Volume 103, 15 September 2015, Pages 414-419.

[4] http://rubitherm.de [5] R.K. Sharma, P. Ganesan, V.V. Tyagi, H.S.C. Metselaar, S.C. Sandaran, Developments in organic solid–liquid phase change materials and their applications in thermal energy storage, Energy Conversion and Management, Volume 95, 1 May 2015, Pages 193-228 [6] G.R. Dheep, A. Sreekumar, Influence of accelerated thermal charging and discharging cycles on thermo-physical properties of organic phase change materials for solar thermal energy storage applications, Energy Conversion and Management, Volume 105, 15 November 2015, Pages 13-19.

[7] A. de Gracia, L.F. Cabeza, Phase change materials and thermal energy storage for buildings, Energy and Buildings, Volume 103, 15 September 2015, Pages 414-419.

[8] M. Delgado, A. Lázaro, J. Mazo, C. Peñalosa, P. Dolado, B. Zalba, Experimental analysis of a low cost phase change material emulsion for its use as thermal storage system, Energy Conversion and Management, Volume 106, December 2015, Pages 201-212.

[9] Nimbus Centre, Cork Institute of Technology. http://Nimbus.cit.ie/tec/case-studies/etb/ [10] PSE Power http://www.pse.ie/wpcontent/uploads/2012/05/GG50-09_1-engl-JV1.pdf

11

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Evaluation of building performance in use – a case study of the Seager Distillery development

Michael CN Lim AECOM, UK michael.lim@aecom.com

David Ross AECOM, UK david.ross@aecom.com

Steve Harper GALLIARD HOMES steve.harper@galliardhomes.com

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Abstract A two-year post-occupancy performance evaluation has been undertaken of the apartments within Galliard Homes’ Seager Distillery redevelopment site in London. The Seager Distillery site is typical of the many new high-density developments in London, reflecting the tightening standards on energy use and pressure on land use. This paper presents the energy and environmental performance of three apartments studied in detail, including the assessment of the performance of the building fabric, MVHR units and the communal heating system.

The paper compares the actual performance against the design intent of the apartments and summarises the performance of the communal heating system in use. It then highlights the reasons for any performance gaps identified, which provide useful learning to both Galliard Homes and the wider building industry.

The study has demonstrated that measurements of the actual performance of the building fabric align with design expectations; however, issues were found in the performance of the MVHR systems in the apartments affecting thermal comfort and energy use. This was further exacerbated by the underperforming communal heating system, where various

1. Introduction There is increasing concern over the potential gap between the design intent of a building and its actual performance in terms of energy and summer comfort conditions. This gap is thought to arise from a variety of sources, ranging from the design of the building and the methods used, through to the buildability, procurement and construction process, which affect build quality, systems integration and commissioning, as well as the handover and operation of the building. This gap in performance could impact on the UK government achieving its aspiration for a lowcarbon economy and its CO2 reduction commitments. It presents a reputational risk to the house-building industry and it could damage consumer confidence in new-housing if energy bills are higher than expected and the buildings overheat.

In light of these concerns, the Technology Strategy Board (Innovate UK) committed up to ÂŁ8 million to fund a four-year Building Performance Evaluation (BPE) programme on both domestic and non-domestic buildings, which commenced in 2010. The overall purpose of the programme was to evaluate the performance of buildings and support the building industry in delivering more energy efficient, better-performing buildings. This was to be delivered through detailed investigation of real buildings under use to derive substantive evidence of actual building performance and to help identify root causes, which need to be collectively addressed by the various sectors of the building industry, to close any identified gaps in delivered performance.

This paper presents the results of a two-year post-occupancy evaluation study undertaken under the TSB BPE programme. It has been carried out on apartments within Galliard Homes’ Seager Distillery redevelopment site in London. This study aimed to develop an insight into a number of important features of recently-built housing, not sufficiently understood, of which (a) to (c) are covered in detail in this paper: a)

The energy performance of the apartments;

b)

The efficiency of the communal heating scheme;

c)

Understand differences between as-designed and actual energy use by the apartments;

building and its services in terms of design,

d)

Whether overheating occurs in the apartments;

installation, commissioning and post-occupancy

e)

Occupant experience and satisfaction with the apartments.

shortcomings have affected its design, installation and operation.

The study highlighted areas for improvement in the

maintenance. Better building handover and occupant access to relevant information were identified to

2. The Seager Distillery site

promote building usability and further contribute

2.1 Overview

to closing the performance gaps.

The Seager Distillery site is a regeneration project by Galliard Homes on the site of a former distillery, which includes the refurbishment of a 19th century warehouse, a new crescent building, office pavilion and residential tower. It is typical of many developments that came forward in the 2000s in London, reflecting the tightening standards on energy use and pressure on land use,

Key Words: Building performance, post-occupancy, communal heating, MVHR, air tightness 14

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which led to the building of high-density apartment blocks, rather than houses.

This site is distinctive in having a communal heating system to provide heating and hot water throughout the development. The main heat source is a gas Combined Heat and Power (CHP) plant supplemented by a biomass boiler and two conventional centralised gas boilers. The apartments are equipped with mechanical ventilation with heat recovery (MVHR) systems for the continuous provision of fresh air ventilation.

Specifically, the study focused on Norfolk House, which is one of the annex blocks completed within the first phase of the development. Norfolk House is considered representative of the site with similar build specification, design and procurement. There are a total of 58 apartments in Norfolk House, which feature fullheight double glazing connecting the living rooms to the balconies.

Various types of cladding have been used on the facade including aluminium insulated panels, aluminium rain-screen cladding, aluminium infill panels, aluminium spandrel panels, and timber cladding. Figure 1 shows the Seager Distillery development and Norfolk House.

Figure 2: Communal heating supplying heat from the energy centre throughout the site.

Figure 3 shows the energy centre, which comprises the following: — An 800kWth wood pellets fired lead biomass boiler to provide low carbon heat; — An Ener-G 100 CHP plant with 165kWth and 100kWe; — An 1000kW Hoval Cosmo gas boiler installed in Phase 1 and 1500kW Hoval Cosmo gas boiler in Phase 2; — An 18,000 litre thermal store to buffer CHP and biomass boiler output.

Figure 1: The Seager Distillery site and Norfolk House.

ELECTRICITY OUTPUT

The study particularly focussed on three apartments comprising the most common build-types within Norfolk House, which are detailed in Table 1. AECOM undertook an independent investigation of the buildings with support from Galliard Homes and Amicus Horizons (social housing provider, who part-owns the apartments). AECOM had no role in the development of the Seager Distillery site.

GAS BOILER 1000kW

GAS BOILER 1500kW

CHP UNIT 100kWe 165kWt HEAT DIVERTING VALVE

PRIMARY HEADER PRIMARY PUMPS

THERMAL STORE 18m3

PRIMARY FLOW

HEAT

BIOMASS BOILER 800kW

PRIMARY RETURN

2.2 Communal heating system FLOW TO THE BLOCKS VIA BLOCK PLANT ROOM HEAT EXCHANGERS AND SECONDARY PUMPED CIRCUITS

Table 1 – Details of the apartment units monitored in detail Flat Number

Internal Floor Area

Number of Bedrooms

Aspect

Floor of Apartment Block

Flat 1

45m²

1

west facing

4th floor

Flat 2

74m²

2

west and east facing (dual aspect)

4th floor

Flat 3

63m²

1

east facing

4th/5th floor (duplex flat)

A dedicated communal heating system provides heating and domestic hot water (DHW) throughout the development. Figure 2 illustrates the communal heating system layout taking heat from the energy centre to the different blocks throughout site, including Norfolk House. Separate building pipe network then distributes heat to the apartments via hydrostatic interface units (HIUs) for space heating and DHW provision.

Figure 3: Block diagram of the communal heating system.

3. Methodology The study was carried out over a two-year period and comprised both quantitative and qualitative evaluation of the performance of the apartments and the communal heating system. Figure 4 illustrates the setup for real-time measurement on site. The following measurements were recorded at 5-minute intervals with the data remotely accessed on a weekly basis by AECOM: — Total electricity, heat (space heating and DHW) and water consumption; — Separate electricity sub-metering of the MVHR system, lighting, power sockets, heating system and cooking hob; — Temperature, relative humidity and CO2 levels within the apartments as well as the local weather condition at the site.

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condition of the filters, which provided a general indication of the level of maintenance of the units.

Seager Distillery Norfolk House Dry riser Remote data collection

Data logger & modem Consumer Unit

Main distribution board

Pulse meter

Flat1

MVHR

Plug monitor

Modem Water meter

Flat3

Pulse meter

Sensor

Air temp CO2 RH

Consumer Unit Heat meter

MVHR Repeater

Plug monitor Air temp CO2 RH

Weather station

Sensor

Water meter Consumer Unit

Pulse meter

Flat2

MVHR

A specialist contractor measured the MVHR air flow rates in each apartment in accordance with the BSRIA Guide BG46/2013, Domestic Ventilation Systems – A Guide to Measuring Air Flow Rates. An air capture instrument was used to measure the air volume from the supply and extract terminals in the apartments, by fully enclosing the terminals with the inlet hood of the instrument.

This instrument has a built-in fan and pressure compensation facility, with an accuracy of ±3% of reading ±1m3/h.

Heat meter Plug monitor Air temp Sensor CO2 RH

Water meter

Community heating Heat meter

Mains water

Electricity mains incomer

Figure 4: Diagrammatic illustration of the real-time measurement setup in Norfolk House.

In addition, plug-in energy meters were used to monitor energy use of selected individual appliances to provide further granularity in the electricity consumption data.

Actual energy consumptions measured for each of the three apartments were compared against their corresponding SAP figures.

SAP or Standard Assessment Procedure is the UK Government's recommended method system for measuring the energy rating of residential dwellings, which is used specifically for building regulation compliance purposes. Comparison using SAP figures has been carried out in the study to benchmark against actual consumption.

In order to assess the build quality of the development, the air leakage and fabric thermal conductive performance of Norfolk House were measured by a specialist contractor:

A series of walk-through audits and visual inspections of building services and the construction details in the apartments were also carried out to identify any issues which might lead to shortcomings in building performance. This was supplemented by feedback obtained through informal occupant and developer interviews and through questionnaires employing the Building User Survey (BUS) methodology (1).

4. Key findings 4.1 Fabric performance The air tightness results are summarised in Table 2, together with the as-designed SAP values as well as the on-completion air tightness testing for the same apartment types (not the actual apartments monitored here) obtained from test certificates issued during construction.

Table 2 – The air pressure test results Air pressure measure

Air permeability at 50Pa (m³/h.m²) Flat 1

Flat 2

Flat 3

— Air tightness tests were carried out in each of the three apartments, initially during the summer of 2013 and then repeated a year later. This testing was undertaken using a “blower-door” test in accordance with the procedures described in the ATTMA technical standard, TSL1 October 2010;

Design air permeability (SAP)

8.0

On completion 4.5 (original testing contractor)

4.2

5.6

Initial air pressure test results in the study

2.4

3.2

3.6

— In-situ U-value tests were carried out to determine the thermal performance of external walls of the apartments using heat flux sensors mounted on internal surfaces, which measured heat flow directly through each wall to correlate with corresponding internal and external air temperatures.

Further inspection of the fabric thermal performance was carried out using thermographic imaging survey on both the interior and exterior of the apartments.

Repeat air pressure test results in the study

2.8

2.6

3.6

The performance of the MVHR system was also investigated: — Measurement of flow rates were compared against commissioned figures and values from Approved Document Part F of the Building Regulations. In addition, continuous measurement of MVHR energy use was combined with flow measurements to determine the fan efficiency of the units; — Visual inspections were carried out where possible to determine both the quality of installation as well as the

16

The initial and repeat air tightness tests undertaken as part of this study were significantly lower than assumed in the design stage SAP assessment and 1 to 2 m³/(h.m²) better than those tested for similar apartments on-completion. Potential causes of the difference between the on-completion and current study testing include the following: — Variations between the actual apartments tested for the corresponding given apartment type; — Changes to the building fabric air tightness over time. This may be due to the building drying-out and settling down.

Furthermore, leakage paths through small gaps in the building fabric may get clogged up; — Significant differences may have resulted from different organisations undertaking the two sets of air tightness tests

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and arisen due to variations in the methodology employed and the calibration of the equipment used. However, there was insufficient data collected to account for the magnitude of discrepancy in the measurements.

Reviewing the literature, it is noted that another study of three rounds of air tightness measurements in 10 low-energy new homes during the first 18 months of occupation also showed a general improvement of the air tightness across the period (2). A further study suggests that the type of dwelling, construction, heating and ventilation all have a bearing on the extent to which air permeability changes over time (3).

windows as shown in Figure 6. Also shown are the thermography images of the underside of some of the apartment balcony floor slabs. It can be seen that the surface temperature is higher at the interface with the external wall, indicating potential thermal bridging caused by the penetration of steel structure.

While the air tightness results were relatively low, smoke tests have identified leakage paths under sinks, wall power sockets and light fittings, which present potential areas for future improvement.

Limited in-situ U-value tests(4) were carried out by a specialist contractor on the general external facing wall of the apartments.

However, there were problems with the testing leading to data only for one apartment and one section of wall. The results suggest that the actual performance is close to the design value (actual value of 0.23 W/m²K compared to a design value of 0.25 W/m²K), although more extensive measurements would be required to verify this finding.

Thermographic imaging (5) was undertaken by a specialist contractor both internal and external to the apartments. This includes measurement of the Thermal Index as a metric for fabric performance. The Thermal Index is the ratio of (surface temperature – external temperature) and (internal ambient temperature – external temperature). The contractor provided a correlation between the Thermal Index and U-value as shown in Table 3.

Figure 5: Thermography images showing (top) cold bridging (dark-blue patches) from dabs on plasterboard and (bottom) from penetration of stud-wall fixings.

(a) MVHR exhaust grille

(b) Thermal bridging around openable window

(c) Thermal bridging along floor penetration

(d) Thermal bridging along floor penetration

Table 3 – Equivalence of Thermal Index and U-values Thermal index 0.50

0.75

0.80

0.85

0.90

0.95

0.97

U-value

1.9

1.5

1.2

0.9

0.35

0.25

3.8

The reported Thermal Index generally suggested actual U-values are in-line with design expectations. Some cold spots were identified, which highlighted potential areas for future improvement. Examples include: (i) colder areas at the top of “boxedin” sections, perhaps covering section of pipe work, with air leakage problems, (ii) cold bridging from large dabs behind the plaster board, and (iii) some evidence of cold bridging due to penetration of stud-wall fixings. Figure 5 shows images of the latter two examples.

No specific anomalies were identified on the external façade from the surveys carried out. It should be noted that glazed sections provide some ambiguity when interpreting fabric performance, which is prevalent for Norfolk House. In addition, a high proportion of its opaque fabric consists of ventilated rain-screen cladding, which further renders the external survey ineffective.

However, salient features remain evident from the survey in the form of higher recorded temperatures related to MVHR outlet vents above windows and thermal bridging around some openable

Figure 6: Thermography image showing heat loss (a) on the external façade of Norfolk House associated with the inlet/exhaust vents of the MVHR system, (b) thermal bridging around an openable window and (c & d) thermal bridging on the underside of the apartment balcony floor slab of Norfolk House potentially due to structural steel penetration at the façade..

4.2 Ventilation: MVHR system The MVHR system is used to provide fresh air supply into the living room and the bedrooms, tempered via heat recovered from return air extracted from the kitchen and bathroom. The MVHR unit is capable of a normal and boost operation with a manufacturerspecified heat recovery effective up to 95% (not tested in the study). Both the supply and extract air are filtered at the MVHR unit.

Visual inspection of the MVHR system in the apartments highlighted several issues which might potentially affect the overall performance in the provision of ventilation and energy use. On first

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impression, it would appear that considerable amount of flexible ducts could have been used at the MVHR unit connections as well as near the extract and diffuser terminations. However, due to limited access it has not been possible to fully ascertain this. There were also some diffuser caps which appear to have been adjusted and these affect flow rate as the locks have not been properly fastened.

In general, the location where the MVHR units were installed made access difficult, being part-constricted by soffit in the airing cupboard, which would require removing to access the MVHR units. A visual inspection of the interior of one of the MVHR units revealed the following, for which photos in Figure 7 illustrate the findings: — The filters were dirty, particularly the extract air filters. This is likely due to the units being installed and commissioned during on-going construction work and, thus, capturing dust.

The occupants appeared unclear as to what maintenance was necessary and who was responsible. Indeed, this is representative of a wider concern from residents that they had not received instruction on the use of their ventilation and heating systems. Impeded access could have further contributed to lack of filter cleaning/change; — The external supply grilles were found to be covered with dust. The location of some of the external grilles does not allow easy access for cleaning.

Table 4 – The MVHR air flow test carried out for Flat 1 Measured in study (l/s) “As-found” “Clean”

Flat 1 Location

Normal

Commissioning data (l/s)

Normal

Boost

Boost Normal Boost

Living room

7.2

10.3

7.8

10.5

7

No data

Bedroom

5.5

7.5

5.5

7.7

6

No data

TOTAL SUPPLY

12.7

17.8

13.3

18.2

13

No data

Bathroom

-7.7

-9.8

-8.9

-13

-7

-13

Kitchen

-2.8

-4.8

-4.5

-6.0

-6

-8

TOTAL EXTRACT

-10.5

-14.6

-13.4

-19

-13

-21

Table 5 – The MVHR air flow test carried out for Flat 2 Flat 2

Measured in study (l/s)

Location

Normal

Commissioning data (l/s)

Boost

Normal

Boost No data

Living room

1.9

2

7

Master bedroom

2.4

3.8

6

No data

Bedroom

3.3

4.4

-

No data

TOTAL SUPPLY

17.6

10.2

13

No data

Bathroom

-3.6

-4.6

-7

-13

Kitchen

-5.2

-6.4

-6

-8

TOTAL EXTRACT

-8.8

-11

-13

-21

Table 6 – The MVHR air flow test carried out for Flat 3

Figure 7: Dirty extract filter (half cleaned for comparison) and clogged up external inlet grille.

Flat 3

BSRIA measured (l/s)

Location

Normal

Commissioning data (l/s)

Boost

Normal

Boost

Living room

4.6

10

7

No data

Bedroom

4.9

10.9

6

No data No data

The measurements of the MVHR ventilation rates for the apartments recorded by the specialist contractor are presented in Table 4 to Table 6. Measurements were also taken after the extract filter of the MVHR unit in Flat 1 was cleaned in order to assess the difference in performance. Upon cleaning, the airflow rates approached those from the commissioning data as shown in Table 4. This observation may also apply to the other two apartments which, if the filters were cleaned, may result in the commissioning test figures being achieved.

TOTAL SUPPLY

9.5

20.9

13

Bathroom

-3.7

-7.6

-6

-8

Toilet

-3.2

-9.9

-4

-6

Kitchen

-3.7

In general, the air flow rates measured on the supply and extract terminal in Flats 1, 2 and 3 are all below the values reported in the commissioning certificates. Furthermore, at normal mode operation, the flow rates did not appear to achieve the recommended ventilation rates in Part F 2006 of the Building Regulations for Flats 2 and 3.

Flat 1

Under-ventilation in dwellings can lead to problems of poor indoor air quality and health. For example, excessive moisture buildup from cooking, bathing and other processes can lead to condensation and mould growth. Occupant exposure to resultant moisture-related allergens can increase the risk of respiratory

18

TOTAL EXTRACT -10..6

-6.8

-7

-13

-24.3

-17

-27

Table 7 – MVHR measured SFPs under normal and boost operations State

Normal (W/l/s )

Boost (W/l/s )

“As-found”

1.34

2.08

“Clean”

1.27

1.95

Flat 2

“As-found”

1.31

2.32

Flat 3

“As-found”

1.51

2.03

symptoms and asthma (6). It should be noted that no health-related issues were reported in this study.

The MVHR Specific Fan Power (SFP) for each apartment is tabulated in Table 7, determined by taking the metered fan power consumption (W) and dividing this by the measured flow rate (l/s) (maximum between the supply and extract rate) for the different

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operating conditions. In all cases the measurements are poorer than the manufacturer stated performance of 0.59 W/l/s. For the case where the extract filter was cleaned and tested, while there was a slight improvement, it was still significantly poorer than the manufacturer’s data.

It is noted that the manufacturer-quoted MVHR performance is based on laboratory testing using, for example, specific lengths and types of ducting, which may not be fully representative of what was actually installed in the apartments. The location of the MVHR unit in the centre of the apartment may lead to the use of unnecessarily long ducts, which increases pressure drops.

Furthermore, as highlighted earlier, the quality of the installation is unknown as ducting is concealed within the ceiling void. This may cause additional pressure drop if, for example, excessive flexible ducting has been used. We note that there is no record that the efficiencies of the MVHR units were measured during commissioning. Furthermore, the manufacturer’s SFP test data was used in SAP for compliance purposes, which would tend to result in a lower predicted energy use than observed, albeit off-set to some degree by the lower air flow rates delivered.

The Zero Carbon Hub and the NHBC Foundation (7) have reported on studies which have consistently identified similar issues with MVHR systems reported here. The report went on to suggest the need for improvement in current practice in respect of design, installation, commissioning, operation and maintenance of MVHR.

4.3 Communal heating system The findings in this section are based on the experience of Galliard Homes on the post-completion handover and operation of the communal heating system as well as additional assessment of efficiency performance of the system carried out during this study.

Issues were identified with regards to the installation and commissioning of the energy plant, particularly with the implementation of the system controls based on a largely underdeveloped controls philosophy from the consultant, which have impacted on its operation. This is compounded by the design specifications for installation and commissioning not being sufficiently detailed and the inexperience of the mechanical and electrical installation company with evaluating such a system.

Table 8 summarises the communal heating system efficiency for four periods of measurement. The system efficiency was determined by comparing the fuel consumption of the gas boilers with the heat meter readings for all apartments. The system efficiencies are much lower than expected with an annual efficiency of 26%.

It is expected that a key cause is significant distribution losses in the heating pipe network. This is evidenced by three results: — The system performance was considerably worse in the summer period. This is likely to be due to reduced heat load to delivering DHW only whilst significant heat losses were still incurred at the pipework; — As shown later in Section 4.4, significant overheating was identified in the apartment communal corridors; — As shown in Section 4.5, actual space heating in the apartments was significantly below that predicted, which could reasonably be expected to result from heat losses in the apartment building itself (communal areas) warming up the apartment units.

Table 8 – The performance of the communal heating system over various monitoring periods during the study between 2012 and 2014 Period

Efficiency 2012

2013

2014

O N D J F M A M J J A S O N D J F

The initial design of the main heating plant with gas boilers, biomass boiler and the CHP engine were estimated at 4,766kW capacity. Although this was substantially reduced at the final plant installation to a capacity of 3,465kW, it was found to be oversized due to a large proportion catering to the provision of DHW, proposed by the Mechanical & Electrical Consultant at the design stage with reference to the BS6700:2006. A more appropriate sizing should have been made via the Danish DS439 standards, which take into account more appropriate diversity factor. This allowance, coupled with the reduction in water flow rates to cater to the Code for Sustainable Homes (CfSH) requirements, would have resulted in the predicted overall demand being much lower.

The study did not evaluate the cause of any such distribution losses, which may be a result of the quality of the installation and/or the actual insulation standards for heating pipework being below what is necessary to achieve a reasonable system distribution loss.

Currently, a heat networks code of practice (8) is being prepared for the UK with an aim to establish minimum standards for district and communal heating network schemes, including issues related to efficiency of performance.

During the course of this study, only the gas boilers have been operating. In particular, the CHP has not run due to it being oversized for the Phase 1 build out. Furthermore, the lowest output available from the 800kW biomass boiler was more than the daytime winter idling load of the completed scheme. This puts future use of the biomass boiler into question. In the Energy Strategy, the biomass boiler was to be 700kW but the final plant selection led to the installation of an 800kW biomass boiler.

At the time of design, the development was specified with pipe insulation thicknesses given by BS5422:2001. Galliard Homes have since moved to adopt the ECA - NES Y50 standard for future projects, which is an enhanced standard for insulation material performance and thickness for heating and hot water services. This should provide approximately 12% reduction in pipework heat loss with +14% cost increase on material cost over the standards, which the Seager development was based on.

Winter

32%

Summer 19% Annual 26% Winter

34%

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As a result of the low system efficiency and the use of gas boilers only, it has been calculated that the CO2 emissions are significantly higher than predicted by SAP. These range from 74% to 182% greater than predicted by SAP, depending on the apartment unit.

It can be expected that the CO2 emissions will improve somewhat as: (i) an increased number of buildings come on-line (i.e. increasing the heat load and improving distribution efficiency), and (ii) the CHP is used.

Galliard Homes have also identified several fundamental design, installation and commissioning issues impacting on the system performance.

— Investigations have revealed additional and unnecessary gas solenoid valve and under-sized gas pipework, which resulted in low pressure to the boilers causing the second gas boiler being unable to run. The gas pipe sizes did not appear on the schematic drawings, which was not flagged up or picked up by the contractor or installer. Galliard Homes now audit all projects to ensure that detailed gas schematics are produced; — There were also issues with inappropriate heating pipework design and commissioning of control valves that consequently led to intermittent disruptions of DHW supply, which took considerable effort for Galliard Homes to identify the cause.

In relation to this, Galliard Homes also found unnecessarily large number of heat exchangers being specified. Improved design and tighter control of commissioning would help alleviate issues leading to supply disruption in future; — There have even been issues with the conventional gas boilers – incorrect wiring of the BMS modulation signal to the gas burner led to Boiler 2 modulations not being controlled correctly which can potentially damage the unit. This was further exacerbated by problems with the air damper control mechanism on one boiler burner, which has caused heat outages resulting in, at times, residents left with no heating for periods of up to 24 hours. Remedial works to the boiler burners have since prevented further outage of the entire system.

4.4 Overheating The 2006 CIBSE Guide A (9) recommends that for living areas, less than 1% of occupied hours should be over an operative temperature of 28˚C and for bedrooms, less than 1% of occupied hours should be over 26˚C. We have assumed that ambient temperature equals to operative temperature (i.e. air temperature equals radiant temperature).

Furthermore, as the apatrments could potentially be occupied for much of the time depending on the activities of the occupants, we have assumed that the bedrooms are occupied from 10pm to 8am, and the living rooms are occupied from 8am to 10pm.

In summary, all three apartments experienced periods of overheating during the summer of 2013 in both the living rooms and bedrooms monitored. In particular, during July 2013, all bedrooms and living rooms overheated for a period between 27% and 58% of occupied hours.

20

This overheating could be due to a combination of (i) the high amount of glazing rendering the apartments susceptible to excessive solar gain, (ii) the MVHR in some of the apartments operating with a ventilation rate below that recommended by Part F of the Building Regulations, which also appear not to feature the capability for summer by-pass, and (iii) the three apartments were all on upper levels of the building such that there was no shading from balconies of the level above, which lower level apartments benefit from.

In addition, another contributor is the likely distribution heat losses within the apartment building from the communal heating system during the summer period. The issue of overheating in the neighbouring 26-storey residential tower building on the site was sufficiently pronounced such that it became necessary to retrofit automatic opening vents in the smoke shaft to purge heat in the summer from the core and communal corridors.

The Building User Survey (BUS) carried out has highlighted that occupants perceived that internal temperatures in summer were too hot and that they have insufficient control of cooling. In addition, BUS feedback on relatively high external noise levels (it is noted that construction was continuing on the site, which will have contributed to external noise) may have resulted in an unwillingness to open windows to reduce the temperature.

NHBC Foundation (10) has highlighted concerns of overheating from recently constructed homes and identified design issues that should be addressed. The report similarly recognises potential problems arising from heat gains from communal heating systems, the need for adequate ventilation and impact of excessive solar gains, all of which are consistent with the observations made in this study.

4.5 Energy use and benchmarking against SAP Measured heat (combined space heating and hot water) and electricity consumption within the apartments collected between March 2013 and June 2014 were compared to that predicted by SAP. For space heating, the heating degree day method using corresponding local measured weather data was used to modify the SAP predictions to better represent the influence of actual weather conditions and approximate the monthly variation in the proportion of space heating.

Figure 8 compares the predicted and measured actual heat consumption in the three apartments. The measured consumption is the lowest for Flat 1 among the three apartment units as it has both the smallest floor area and only one external façade, whereas the other two apartments have a larger floor area and larger external wall area with dual-aspect external façade for Flat 2. Flat 3 is a duplex unit over two storeys.

SAP over-predicted the heat consumption. The actual heat load would tend to be reduced by both better actual air tightness and observed ventilation rates being less than assumed by the SAP assessment. Furthermore, the apartments are thought to benefit from (unmeasured) heat gains arising from the distribution heat losses from the communal heating system (see Section 4.3).

Figure 9 shows the energy use for fans and pumps in the

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SAP

800

600 500 400 300 200 100

Sep-13

Oct-13 Jun-14

Jul-13

May-14

SAP

800

Aug-13

Flat 2

Apr-14

Jun-13

Apr-13

May-13

Oct-13

Mar-13

Sep-13

Jul-13

Aug-13

Jun-13

Apr-13

May-13

Oct-13

Mar-13

Sep-13

Jul-13

Aug-13

Apr-13

May-13

Jun-13

0

Flat 1

Flat 3

Actual

700 600 500

400 300 200 100

Flat 1

Feb-14

Mar-14

Jan-14

Dec-13

Nov-13

Jun-14

May-14

Apr-14

Feb-14

Mar-14

Jan-14

Dec-13

Nov-13

Jun-14

May-14

Apr-14

Feb-14

Mar-14

Jan-14

Dec-13

0

Nov-13

Heat (Space heating & DHW) [ kWh ]

results from Flat 1 were similar to SAP prediction. However, both Flat 2 and Flat 3 used significantly less lighting than predicted. This may be explained by the feedback from the occupants of these two apartments who preferred stand-alone lighting, which used power from the wall sockets.

Actual

700

Mar-13

Heat (Space heating & DHW) [ kWh ]

Evaluation of building performance in use – a case study of the Seager Distillery development

Flat 2

Flat 3

Figure 8: SAP and actual heating energy use for the three apartments for March 2013 to the end of June 2014.

SAP

35.0

Table 9 provides an overall summary of the annual SAP predicted and actual energy consumption (space heating, hot water and electrifty for fan, pumps and lighting) for the three apartments. It also shows the total measured energy use including that measured for power sockets for comparison between each apartment units.

Actual

30.0

Lighting [ kWh ]

The electricity use for stand-alone lighting was not separately measured to reconcile this lower-than-predicted consumption of fixed lighting. This reduced the need, and thus energy consumption, for ceiling lights which were on the lighting circuit.

There is no evidence in this study to suggest that the reduced energy use for artificial lighting was linked to provision of good daylight in the apartments, which was not investigated in the study.

Finally, it is also noted that 100% low energy lighting was installed in the apartments, which is greater than that assumed in SAP and would tend to further reduce the actual energy use.

25.0 20.0

15.0 10.0 5.0

Flat 1

Flat 2

SAP

45.0

Oct-13

Sep-13

Aug-13

Jul-13

Jun-13

May-13

Apr-13

Oct-13

Sep-13

Aug-13

Jul-13

Jun-13

May-13

Apr-13

Oct-13

Sep-13

Aug-13

Jul-13

Jun-13

Apr-13

May-13

0.0

Flat 3

Table 9 – Comparison of annual regulated energy consumption between measured and SAP predictions for the three apartments

Actual

40.0

Lighting [ kWh ]

35.0 30.0 25.0 20.0 15.0 10.0 5.0

Flat 1

Flat 2

Jun-14

May-14

Apr-14

Feb-14

Mar-14

Jan-14

Dec-13

Nov-13

Jun-14

May-14

Apr-14

Feb-14

Mar-14

Jan-14

Dec-13

Nov-13

Jun-14

May-14

Apr-14

Feb-14

Mar-14

Jan-14

Nov-13

Dec-13

0.0

Apartment Unit

SAP

Actual

30.0

Lighting [ kWh ]

Electricity – fan, pump, lighting

Flat 3

25.0

Total actual including power sockets use

SAP

Actual

SAP

Actual

kWh/m2/yr

kWh/m2/yr

kWh/m2/yr

kWh/m2/yr

kWh/m2/yr

Flat 1

66.84

22.97

5.86

9.77

67.23

Flat 2

75.16

46.22

5.86

2.73

68.83

Flat 3

78.76

29.21

6.54

3.72

54.03

Figure 9: SAP and actual fans and pumps energy use for the three apartments for March 2013 to the end of June 2014.

35.0

Space heating and hot water

20.0

15.0 10.0 5.0

Flat 1

Flat 2

SAP

45.0

Oct-13

Sep-13

Aug-13

Jul-13

Jun-13

May-13

Apr-13

Oct-13

Sep-13

Jul-13

Aug-13

Jun-13

May-13

Apr-13

Oct-13

Sep-13

Jul-13

Aug-13

Jun-13

Apr-13

May-13

0.0

Flat 3

5. Lessons learned

Actual

40.0

Lighting [ kWh ]

35.0

Galliard Homes have identified a series of lessons learned from this study, several of which are highlighted below:

30.0 25.0 20.0 15.0 10.0 5.0

Flat 1

Flat 2

Jun-14

May-14

Apr-14

Feb-14

Mar-14

Jan-14

Dec-13

Nov-13

Jun-14

May-14

Apr-14

Feb-14

Mar-14

Jan-14

Dec-13

Nov-13

Jun-14

May-14

Apr-14

Feb-14

Mar-14

Jan-14

Dec-13

Nov-13

0.0

Flat 3

Figure 10: SAP and actual lighting energy use for the three apartments for March 2013 to the end of June 2014.

apartments. In this case, the actual consumption tends to be higher than predicted by SAP. This was partly due to occupant behaviour with Flat 1 continuously using the MVHR on boost setting until the start of 2014 when the occupant was made aware by the investigating team of how to use the ventilation controls. Another key reason is the efficiency of the MVHR units being less than half of that given by the product test data used in SAP. However, this was tempered somewhat by the ventilation rates in Flat 2 and Flat 3 being lower than recommended by Part F. Figure 10 shows the lighting consumption for the apartments.The

— Appraisal of the communal heating scheme design at the Seager development has led to recommendation for different design approaches to be adopted for 100 to 300, and 1000 or more apartment development sizes, which is vital for the design, to adequately account for phased completion. For example, smaller schemes below 300 units can have primary heating water delivered from the plant room directly to the radiator circuits in the apartments without any heat exchanger break. Also, phasing would require separate pumped circuits to each block to facilitate phased commissioning of the heating system. This would allow heat meters to be fitted to each circuit so that residents who have moved in could be charged accordingly and fairly; — Plant oversizing was found to result from the lack of appropriate adjustments to accommodate changes in the

21

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SDAR Journal 2015

demand, as the site design evolved. This then led to issues with plant operability in practice. This is further exacerbated during the planning stage whereby plant sizing was derived based on a methodology to achieve CO2 reduction to meet planning targets, which does not appropriately account for diversity in DHW demand. Also, it is vital that compliance calculations are not used for plant sizing and design calculations. References to the Danish DS439 standards for more appropriate account of diversity in DHW demand would further inform appropriate plant sizing; — Current pipework insulation standards may be insufficient to limit heat loss, prevent corridors and apartments from overheating and to prevent heat gains in the mains water.

Galliard Homes are now moving towards adopting the ECA – NES Y50 Enhanced insulation standard (11) (12); — Appropriate levels of heat metering should be installed to enable measurement of system operation and performance.

This will enable better management of heat billing during phased completion; — Issues were identified with regard to the installation and commissioning of the energy plant, particularly with the system controls, which have impacted on its operation. Key learning points are the need for more detailed design specifications for installation and commissioning and the procurement of an experienced mechanical and electrical installation company, capable of delivering to expected standards; — Detailed BMS control philosophy is essential to ensure accurate description of system operation and facilitate precise implementation by installers; — A more prescriptive and robust commissioning requirement would help ensure the various issues encountered with the communal heating system, as well as the MVHR units in the apartments, could be significantly minimised; — Feedback from the occupants was that whilst a large amount of useful information was provided in the form of documentation, it did not provide all of the practical information. In particular, it was recommended that face-toface orientation/handover would have been helpful. This should include the correct operation and maintenance of the MVHR system. Points raised in this study included the inappropriate use of the boost switch and clogged up extract filters and external inlet grilles.

6 Summary Overall, the heat consumed by the three apartments is significantly less than that predicted in SAP. Contributing factors are found to be high fabric thermal performance, low ventilation rates and uncontrolled gains from solar and heating pipe distribution losses.

While fabric thermal performance reflected well-executed design intent, low ventilation rates were a result of the under-performing MVHR system, which also led to relatively higher associated energy use. Sources of heat gains, which may be desirable in winter,

22

exacerbated the risk of overheating in the apartment and thermal comfort in the summer.

The electricity use for fixed building services within the three apartments is more variable in comparison with SAP, reflecting the diverse nature of occupant behaviour and hence the use of the building. For example, the occupant preference for standalone lighting in two apartments resulted in lower measured fixed lighting energy than predicted for these apartments but with increased demand from power sockets where stand-alone lighting was used.

While a large amount of information was provided in the form of documentation, the occupants identified that it did not provide all of the practical information. Face-to-face orientation would have been helpful. For example, the electricity consumption highlighted that one occupant was unaware of continually using the MVHR system on boost setting and discussion with the occupants suggested lack of clarity on responsibility for maintenance.

The communal heating system has not performed to expectation with low overall system efficiency, largely thought due to high distribution losses in the heating pipe network. Distribution losses in the communal heating pipe could be the result of the quality of pipework installation and/or the standards of insulation on heating pipework being below that necessary to achieve reasonable losses.

Faults due to the generally poor quality of design, installation and commissioning have also contributed to heat outages, poor performance and under-utilisation of the low carbon technologies (biomass boiler and CHP engine) intended to reduce CO2 emissions.

The study has highlighted some clear issues, which have resulted in performance gaps between the design and actual building performance. The causes identified cover the entire process, from the design stage, through to the quality of the construction process, and finally to the commissioning of the building services and handover to the building occupants such that they understand how, and are motivated to, operate the building in a correct and energy-efficient manner. Indeed, the highly-diverse occupant behaviour in a domestic setting results in an inherent tendency for significant differences between actual and predicted performance.

This should also be recognised when highlighting the performance gap.

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Evaluation of building performance in use – a case study of the Seager Distillery development

References (1) BUS Methodology, URL: http://www.busmethodology.org (2) NHBC Foundation and Zero Carbon Hub, NF52 Assessment of MVHR systems and air quality in zero carbon homes. NHBC Foundation, 2013 (3) NHBC Foundation, NF24 Ageing and air tightness – how dwelling air permeability changes over time. NHBC Foundation, 2011 (4) BS ISO 9869-1:2014 Thermal insulation – building elements – in-situ measurement of thermal resistance and thermal transmittance. Heat flow meter method, British Standards Institution, 2014 (5) Pearson C, BG 39/2011 – Thermal Imaging of Building Fabric, BSRIA, 2011 (6) Ucci M, Ridley I, Pretlove S, Davies M, Mumovic D, Oreszczyn T, McCarthy M, Singh J, Ventilation rates and moisture-related allergens in UK dwellings, 2nd WHO International Housing and Health Symposium, Vilnius, Lithuania, 2004 (7) Zero Carbon Hub and NHBC Foundation, Mechanical Ventilation with Heat Recovery in New Homes. London: Zero Carbon Hub, 2013 (8) Heat Networks: CP1 Code of Practice for the UK, CIBSE & CHPA, 2014 (draft) (9) CIBSE, Guide A (2006) Environmental Design, 7th edition, London, 2006 (10) Richards Partington Architects, Understanding Overheating – Where to Start, NHBC Foundation, Zero Carbon Hub and RPA, 2012 (11) Energy Technology Criteria List, Department of Energy and Climate Change, 2013 (12) Kooltherm FM – HVAC & Building Services Pipe Insulation, Kingspan Tarec, 2014

Acknowledgements The authors would like to take the opportunity to express their gratitude to the Technology Strategy Board (Innovate UK) for funding the study under the Building Performance Evaluation programme.

Glossary MVHR SAP

Mechanical Ventilation with Heat Recovery Standard Assessment Procedure is the UK Government's recommended method system for measuring the energy rating of residential dwellings.

ECA Enhance Capital Allowance is a scheme whereby a business can invest in energy-saving plant or machinery that might otherwise be too expensive. The first year allowances let businesses set 100% of the cost of the assets against taxable profits in a single tax year.

NES Y50 Standard of enhanced pipework insulation specification CfSH Code for Sustainable Homes is an environmental assessment method for rating and certifying the performance of new homes in England, Wales and Northern Ireland.

SFP Specific Fan Power BMS Building Management System DHW Domestic Hot Water BUS Building User Survey or BUS is a licensed methodology created from thirty years of continuous development in building use studies for post occupancy evaluation.

NHBC National House Building Council CHP Combined Heat and Power BPE Building Performance Evaluation

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First steps in developing cement-based batteries to power cathodic protection of embedded steel in concrete

Dr Niall Holmes SCHOOL OF CIVIL & STRUCTURAL ENGINEERING, DUBLIN INSTITUTE OF TECHNOLOGY niall.holmes@dit.ie

Dr Aimee Byrne SCHOOL OF CIVIL & STRUCTURAL ENGINEERING, DUBLIN INSTITUTE OF TECHNOLOGY aimee.byrne@dit.ie

Professor Brian Norton PRESIDENT DUBLIN INSTITUTE OF TECHNOLOGY president@dit.ie

SDAR Journal 2015

Abstract This paper presents the first steps in developing

1. Introduction

innovative cement-based batteries to power cathodic

Cement could be considered as green as it is a rock-based material, ground into a fine powder and mixed with other raw components.

However, as a result of the rock extraction and mixing, its green credentials are somewhat lost. Therefore, sustainability discourse related to cement primarily focuses on efforts to make it more environmentally friendly over its whole life to diminish the CO2 released during its production.

protection in reinforced concrete structures. Initial electrical outputs of 1.55V and 23mA have been found to be sufficient to polarise prescribed corrosion currents of 20mA per m2 of embedded steel. Cathodic protection is a well-developed and powerful technique to limit the effects of steel reinforcement corrosion.

However, as it requires an electrical supply day and night, it is often powered by non-environmentally friendly diesel generators or connected to the electrical grid. This paper focuses on increasing the ionic conductivity of the solution in the cement pores, increasing the porosity of the cement, examining ways of sealing moisture into the cement and comparing different electrode materials and treatments. The batteries presented consist of different combinations of Portland cement, water, carbon black and salt solutions with embedded copper acting as the cathode and magnesium, aluminium or zinc cast as the anode.

The preliminary findings demonstrate that cement-

However, cement-based products such as concrete can facilitate energy efficiency in the finished structure. This includes the harnessing of concrete’s thermal mass to reduce heating and cooling needs for buildings by absorbing heat (daytime solar gains or when indoor heating system is turned on), storage and later release (at night through the release of these solar gains).

A lot of work is ongoing to reduce the environmental impact of cement-based materials while still maintaining performance (Nanukuttan et al, 2010; EN206, 2000). This includes replacing cement with supplementary cementitious materials such as ground granulated blastfurnace slag and pulverised fuel ash. Other areas of research consider the replacement of natural aggregates in concrete with materials that would otherwise be landfilled, including crumb-rubber (Holmes et al, 2014) and bottom ash (Sandhya et al, 2013).

This paper presents the first steps in developing novel cementbased batteries designed to power low-energy cathodic protection.

One example is Impressed Current Cathodic Protection (ICCP) of reinforcement in concrete structures. ICCP protects reinforcing steel from corrosion by connecting it to an inert, less noble, metal and passing low-level current through it using an external power source (Polder, 1998).

based batteries can produce sufficient sustainable electrical outputs with the correct materials and

2. Background

arrangement of cast-in anodes. Work is ongoing to

In a battery, ions move through the electrolyte and electrons move through the circuit from the anode to the cathode (see Figure 1).

Conventional alkaline batteries use zinc as the anode, manganese dioxide compact as the cathode and salt solution as the electrolyte, with all components held together in a sealed container.

determine how these batteries can be recharged using photovoltaics which will further enhance their sustainability properties.

Key Words: Cement-based batteries; electrolyte; pore conductivity; concrete; corrosion; cathodic protection.

Glossary: Impressed current cathodic protection (ICCP).

Figure 1: Conventional battery arrangement.

26

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First steps in developing cement-based batteries to power cathodic protection of embedded steel in concrete

The electrolyte in a battery is an ionic conductor but also an electronic insulator which resists the movement of electrons. The ionic conductivity of the electrolyte should be high with a low electrical resistance, thus allowing the battery to carry high current (Meng and Chung, 2010). Liquid electrolytes traditionally perform better in batteries due to the high mobility of ions with a continuous interface between electrodes and electrolyte. Examples of solid electrolytes are polymers or ceramics doped with ions to improve ion movement.

The process of embedded steel corrosion in concrete is an example of ionic flow through hardened concrete. During corrosion, iron atoms are removed from the steel surface by electrochemical reaction. These atoms then dissolve into the surrounding electrolyte solution which, in concrete, can only occur where pores exist at the steel anodic site. Electrons must therefore transfer from this anodic site to a cathodic area, which develops a surplus of electrons. The transfer of electrons occurs along the metal and creates a current between areas of differing potential. The ions from the reactions, such as the ferrous ion (Fe2+), pass into the solution trapped in the concrete pores and meet with hydroxyl ions (OH-) to form ferric hydroxide which further reacts to form rust as shown in Figure 2.

Meng and Chung (2010) provided the initial proof of concept that cement-based batteries could be designed to supply a voltage and current.

Figure 2: Corrosion process in embedded steel in concrete.

In their layered design the cathode was a mix of manganese dioxide particles and cement, the electrolyte consisted of cement and the anode contained cement and zinc particles (see Figure 3).

The advantage of this design over electrode (non-cement-based) probes is that the active phase in both anode (zinc) and cathode (manganese dioxide) are in direct contact with the electrolyte (pore solution in the cement paste) in the anodic and cathodic layers and not just at the interface with the electrolyte (Meng & Chung, 2010).

The outputs from this type of battery design were very low. Opencircuit voltages of up to 0.72V and current up to 120 ÂľA (current density 3.8ÂľA/cm2) were recorded and only operated when saturated.

Rampradheep et al (2012) used similar constituents in a layered battery to produce a maximum voltage of 0.6V and an undisclosed current. Cement-batteries cast with carbon fibers and carbon nanotubes in the electrolyte layers (Qiao et al, 2014) yielded maximum power outputs of 0.7V and 35.21ÂľA/cm2.

There is little published research into the possibility of using batteries for generating low-level electrical power for use in ICCP and none, at the time of writing at least, on using cement-based batteries. As this area is so lightly researched there have not been many advances in making these batteries more efficient, powerful, longer-lasting and rechargeable.

A seawater battery to incorporate cement between the magnesium and carbon probes and maintained in a seawater bath has been reported (Ouellette & Todd, 2014) as a corrosion-based energy harvester. Adding the cement passively limited the amount of consumable oxygen rather than a functioning electrolyte system.

As discussed previously, corrosion of reinforcement in concrete creates differing potentials in the steel and induces a current to flow. This corrosion energy can be harvested and used for corrosion sensors (Ouellette and Todd, 2014; Qiao et al, 2011).

3. Methodology The design considerations for the cement-based battery developed here are outlined below. Firstly, increasing the ionic conductivity of the cement electrolyte will improve the performance. For this, water-soluble salts such as Epsom, Alum and sodium chloride are investigated in solution and as solid granules.

The electrically active additive carbon black enhances the connectivity between electrodes. This is particularly true for the cathode which may use an electrochemically non-conductive material such as manganese dioxide (Meng and Chung, 2010). The volume of carbon black added should be high enough to aid electronic connectivity but not so high as to reduce the proportion of the cathode and anode.

For conductive materials such as zinc (which forms electrically nonconductive zinc oxide on its surface), thin reaction products can impede the output of the battery as they reduce the interface between the electrodes and electrolyte. Such layers can be removed by washing with acetic acid and rinsing with a volatile liquid such as ethanol prior to adding to the mix.

Both the anodes and cathodes need to be electrical conductors.

The anode is the more active of the two as it undergoes chemical oxidation during discharge and will be lost over time, thereby losing electrons. The cathode is nobler than the anode and remains more stable during discharge as it gains electrons.

As a battery discharges its internal resistance increases as the electrolyte becomes less conductive. Its open circuit voltage decreases as chemicals become more dilute. The results here present the current and voltage under load.

Figure 3: Layered cement-based battery (Meng and Chung, 2010).

Layered battery The first cement-based battery cast is shown in Figure 4 and was based on the work by Meng and Chung (2010). However, the mix

27

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SDAR Journal 2015

Table 1 – Mix proportions used - layered battery

Electrical contacts 10mm 5mm

Cement-based Anode Cement-based Electrolyte

20mm

Cement-based Cathode

Cathode

MnO2 Water reducer Distilled water Carbon black

218 11 22 15

Electrolyte

Cement Water reducer Distilled water

88 4 18

Anode

Cement Zn Water reducer Distilled water Carbon black

282 84 5 91 7

Electrical output

150x150mm

Figure 4: Layered battery schematic.

Electrical contacts 10mm 5mm

Cement-based Anode Cement-based Electrolyte

20mm

Cement-based Cathode

Electrical output

150x150mm

(a) Layered cement-based battery

adequate mixing before being pressed into the mould. The cathode layer was placed first, followed by a single ply of tissue to prevent drying shrinkage cracks and to ensure the separation of the layers.

The electrolyte layer followed (also covered with a tissue) and finally the anode was applied, which was levelled using a trowel. The battery was left to cure in the mould for 24 hours under damp hessian and polythene sheets. After removal from the mould, readings for open-circuit voltage and resistor load current were taken using a multimeter. This battery is shown in Figure 5a.

Four batteries were made using this design. Two were placed in distilled water to cure for a further 48 hours after removal from the mould (Figure 5b). The other two were placed in a 0.5M solution of Epsom salt (MgSO4.7H2O) for 48hrs (Figure 5b).

(b) Batteries stored in water and Epsom salt

(c) Electrical contacts (conductive copper) Figure 5: Layered batteries cast.

resulted in an unworkably-dry paste for the electrode layers which crumbled when set. The electrolyte layer was too wet and sandwiched out of the mix when the top layer was placed. The proportions of the mix are shown in Table 1. The zinc powder was washed with acetic acid to remove any dirt or oxide layers and rinsed with ethanol to remove the acid prior to mixing.

The surface of the moulds was oiled and the dry components were mixed together before adding the water-reducer and water. The addition of carbon black in the electrode layers made the mix difficult to manipulate and it had to be kneaded to ensure

28

Figure 6: Battery housed in a metal can.

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First steps in developing cement-based batteries to power cathodic protection of embedded steel in concrete

One Epsom salt battery and one distilled water battery were sealed with Sikagard 680S protective coating to maintain the internal moisture content. Electrical contacts were made using conductive copper tape as shown in Figure 5c.

Cement-based batteries housed in a can Cement batteries in this form (Figure 6) were not identified in academic publications, but are prevalent in internet discussion forums, blogs and “how to” videos. They are designed in much the same way as traditional batteries with copper usually being chosen as the cathode. The anode container is usually made from commercial aluminium cans with the top cut off and the sides sanded to expose the aluminium. For the work presented here, the cathodes were chosen as thin copper plates (or hollow narrow tubes) and an eraser prevented short circuiting between the bottom of the catode and the base of the container. A basic cement and water mixture was used as the initial electrolyte.

Various mix designs and additives were compared using this battery form and used to examine the natural recharge abilities (or natural charge build-up and storage abilities) when a resistor load was removed for set periods of time.

An example of the decay in current for the can battery is shown in Figure 8a. As can be seen there is a sudden drop when the opencircuit is lost and the resistor is applied from approximately 19.3 to 4.8mA. Over the next seven days, the current drops below 1mA. Figure 8b shows the natural recharge/storage when the resistor is removed after one month and no current is being drawn out.

Regardless of the length of recharge time (one or two hours), the increase in initial current is the same, as is the long-term value.

Block battery results Voltage and current was measured through a 10Ω resistor and averaged once they became quasi-steady. Figure 9 shows the results from the parametric study. In terms of water to cement ratio (w/c) (Figure 9a), the current steadily increased with water content.

Cathode to anode ratios (Cu:Al) 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1.4 were created using different cut-plate sizes in the same basic cement paste with no discernible correlation. Distances between electrodes of 5mm, 10mm, 30mm, 60mm and 80mm were compared with no differences in output observed. As per the can batteries, the addition of carbon black (Figure 9b) had a significant impact on the measured outputs with lifespan, current and voltage increases of 33%, 44% and 13% respectively.

Cement-based batteries housed in a block These battery types are similar to the can but both the anode and the cathode are in the form of metal plates (Figure 7).

Plastic moulds were used to prevent short circuiting and to allow for a higher volume of sample to be made. These designs were used to compare different additives, anode materials, shapes and sizes.

This type of design is the “best-fit” for cement-based batteries for using with ICCP as they can be incorporated into a cladding panel and fixed onto a structure. For this, particular characteristics are required, namely robustness, long life and a low but consistent current output under resistance load.

4. Results Layered batteries Hourly current and voltage measurements were taken from the battery using a 10Ω resistor. A very low current was generated (0.001mA) in the intervening hours but dropped back to 0mA within 10sec. As shown previously by Meng and Chung (2010), the batteries do not work once dried out. After 30 hours all batteries had ceased to output electrical energy.

The air-dried Epsom salt solution did not display any measurable current with only a minor difference upon sealing. Voltage did increase over time as the battery dried as shown in Table 2.

Can batteries Table 3 presents the results of each mix compared with the basic cement and water combination. As can be seen, there was no noticeable increase in output from the addition of sand with decreases observed when zinc, manganese dioxide were added, as well as increasing the anode ratio. The higher outputs came from increasing the cathode ratio.

Figure 6: Battery housed in a metal can.

Table 2 – Current, voltage and lifespan results from the layered batteries Type/Age

0hrs

Epsom solution V = 0.2V air dried I=0

24hrs

27hrs

30hrs

V = 0V I=0

V = 0.995V I=0

V = 0.489V I=0

Epsom solution V = 0.030V, V = 0.037V, sealed I = 0-0.001mA I = 0-0.001mA

V = 0.23V V = 0.51V I = 0-0.001mA I = 0-0.001mA

Water air dried V=0.310, V = 0.442 I = 0-0.001mA I = 0-0.001mA

V = 0.400V I=0

Water sealed

V = 0.6V I = 0-0.001mA

V=0.380 V = 0.386, V = 0.37 V = 0.737V I = 0-0.004mA I=0.002-0.042mA I = 0-0.004mA I = 0- 0.001mA

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Table 3 – Effect of additives on the power output in the can batteries Additive

Current

Voltage

+Sand

=

=

+Carbon black

↑

↑

+Zinc Dust

↓

=

+Manganese dioxide dust

↓

=

Higher anode ratio

↓

↓

Higher cathode ratio

↑

↑

anode was in a ribbon shape rather than plate and this may have impacted the results. The zinc anode battery design showed very poor results. However, the magnesium anode battery design provided the highest current and lifespan during testing. Current and lifespan increased by 1000% and 350% respectively compared to the base battery with an aluminium anode.

Initial battery testing, with prioritised current and lifespan, indicates that optimal output could be achieved by designing high w/c ratios, the addition of carbon black, adding salt granules, using magnesium as the anode material and sealing the battery to retain hydration and reaction components and products.

A A

Electrical contacts 10mm 5mm

Cement-based Anode Cement-based Electrolyte

20mm

Cement-based Cathode

Electrical output

150x150mm

B

B

Figure 8: (a) typical current discharge and (b) natural re-charge/storage of a can battery.

The base mix contained only distilled water as the solution. In the other three battery designs, no water was added but different 5-Molar salt solutions were included. These were sodium chloride (NaCl), Alum salt (AlKO8S2.12H2O) and Espom salt (MgSO4.7H2O). Compared to the base mix, the use of salt solutions decreased the current by 20% (Figure 9c) with Epsom salt having the least loss of 14%.

Voltage also decreased with the addition of the salt solutions.

However, the lifespan was greatly increased, by 50% on average.

By adding salt to the battery mix in granular form, the current and lifespan increased by 15% and 62.5% respectively, compared to the base mix (Figure 9d).

All battery designs to this point have used copper cathodes and aluminium anodes. Anodes of aluminium, zinc and magnesium were also prepared with the same surface area. The magnesium

30

C

D Figure 9: Results of the parametric study to assess the effects of (a) w/c ratio, (b) carbon black additive, (c) salt solution and (d) salt solution and salt granules.

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First steps in developing cement-based batteries to power cathodic protection of embedded steel in concrete

5. Five potential applications of this research for cathodic protection ICCP limits the corrosion of a metal surface using inert anodes and impressing a current onto the cathode surface using an external direct current (DC) source. For steel reinforcement the recommended (Polder et al, 2009) design current density is 20mA/m2, which refers to the circumferential surface of the bars.

While the currents seen here are low, previous work has shown that lower values for protective current can be successfully used in ICCP to prevent embedded steel corroding (Polder et al, 2009; Glass et al, 2001; Glass and Chadrick, 1994; Glass and Buenfeld, 1995; Koleva et al, 2006; McArthur et al, 1993).

There have been limited but reliable examples of where intermittent current supply has provided adequate cathodic protection to structures (Glass et al, 2001; Glass and Chadrick, 1994; Glass and Buenfeld, 1995; Koleva et al, 2006; McArthur et al, 1993; Christodoulou et al, 2010; Kessler et al, 1998). The ability of cement-based batteries to recharge when the load is removed has been shown here. Stand-alone cement batteries could power the process using a switching mechanism between individual units allowing them to discharge and recharge multiple times.

6. Conclusions Can-shaped batteries have shown to have the longest lifespan.

However, these batteries have a very low output range and need further development. Connecting them in parallel or series to increase output is ongoing.

Carbon black proved to increase output, particularly current and increase longevity due to its ability to increase the connectivity between conductive materials. However, due to its fineness, it makes the batteries considerably brittle so a water reducer is essential.

Although salt solution increased longevity, adding the same salts in solid granule form was even more beneficial and increased current output. When salts are dissolved in water they break up and move through the liquid.

Copper was consistently used as the cathode material in all tests as it is highly noble and easily available. Comparing aluminium, zinc and magnesium anodes, it was found that magnesium produced a substantial improvement in all areas, particularly current and longevity. Open circuit potential values of -1.344V for untreated magnesium, -0.786V for zinc and -0.524V compared to copper (Bullis, 2014) indicates that the highest outputs should occur for magnesium followed by zinc and aluminium.

Layered cement batteries cease to work once dry and this paper presents some first steps in sealing layered-style batteries. Further research into different sealing techniques could help maintain moisture and therefore increase the longevity of batteries.

The possibility of connecting cement-based batteries in parallel has not yet been explored in the research but could be a way of increasing the current output and longevity from the batteries.

References CBullis K (2014) Storing the Sun, Aquion manu-factures cheap, longlasting batteries for storing renewable energy [Available from: http://www.technologyreview.com/demo/524466/storing-the-sun/].

Christodoulou C, Glass G, Webb J, Austin S, Goodier C (2010) Assessing the long term benefits of Impressed Current Cathodic Protection, Corrosion Science, Vol. 52(8), pp 2671-2679.

BS EN 206 Part 1, Concrete (2000) Specification, performance, production and conformity, British Standard Institute.

Glass GK, Hassanein AM, Buenfeld NR (2001) Cathodic protection afforded by an intermittent current applied to reinforced concrete, Corrosion Science, Vol. 43(6), pp. 1111-1131.

Glass GK, Chadwick JR (1994) An investigation into the mechanisms of protection afforded by a cathodic current and the implications for ad-vances in the field of cathodic protection, Corrosion Science, Vol. 36(12), pp. 2193-2209.

Glass GK, Buenfeld NR (1995) On the current density required to protect steel in atmospherically exposed concrete structures, Corrosion Science, Vol. 37(10), pp. 1643-1646.

Kessler RJ, Powers RG, Lasa IR (1998). Intermittant cathodic protection using solar power, Corrosion. San Diego.

Koleva DA, Hu J, Fraaij ALA, Stroeven P, Boshkov N, van Breugel K (2006) Cathodic protection revisited: Impact on structural morphol-ogy sheds new light on its efficiency, Cement and Concrete Composites, Vol. 28(8), pp.696-706.

Nanukuttan, S.V., Holmes, N., Srinivasan, S., Basheer, L., Basheer, P.A.M., Tang, L. & McCarter, W.J. (2010), Methodology for designing structures to withstand extreme environments: Performance-based Specifications, pp. 663-670, Bridge and Concrete Research in Ireland Conference, DIT & TCD, September.

McArthur H, D’Arcy S, Barker J (1993) Cathodic protection by impressed DC currents for construction, maintenance and refurbishment in reinforced concrete, Construction and Building Materials, Vol. 7(2), pp. 85-93.

Meng Q, Chung DDL (2010) Battery in the form of a cement-matrix composite, Cement and Con-crete Composites, Vol. 32(10), pp.

829-39.

Ouellette SA, Todd MD (2014) Cement Seawater Battery Energy Harvester for Marine Infrastructure Monitoring, Sensors Journal, Vol. 14(3), pp. 865-872.

Polder RB (1998) Cathodic protection of rein-forced concrete structures in the Netherlands – Experience and developments: Cathodic protection of concrete - 10 years experience. Heron, Vol. 43(1), pp. 3-14.

Polder R, Kranje A, Leggedoor J, Sajna A, Schuten G, Stipanovic I (2009) Guideline for smart cathodic protection of steel in concrete: Assessment and Rehabilitation of Central Euro-pean Highway Structures.

Qiao G, Sun G, Li H, Ou J (2014) Heterogeneous tiny energy: An appealing opportunity to power wireless sensor motes in a corrosive environment, Applied Energy, Vol. 131(0), pp. 87-96.

Qiao G, Sun G, Hong Y, Qiu Y, Ou J (2011) Remote corrosion monitoring of the RC structures using the electrochemical wireless energy-harvesting sensors and networks, NDT & E Inter-national, Vol. 44(7), pp. 583-588.

Rampradheep GS, Sivaraja M, Nivedha K (2012) Electricity generation from cement matrix incor-porated with self-curing agent, Advances in Engineering, Science and Management (ICAESM), 2012 International Conference, 30-31 March, pp. 377-82.

Sandhya B and Reshma E.K (2013) A study on mechanical properties of cement concrete by partial replacement of fine aggregate with bottom ash, International Journal of Students Research in Technology & Management, Vol 1(4), August, pp 416-430.

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THE IRISH LIGHTER & YOUNG LIGHTER AWARDS The Irish Lighter and Young Lighter Awards are annual applied research events promoted jointly by CIBSE and DIT. They are open to all building services professionals, with SLL members particularly encouraged to participate.

Projects must be located in Ireland, and submissions can also be made which are based on lighting research. Best abstracts are selected by a distinguished international panel of assessors and a shortlist of entrants is then invited to submit full papers.

For the Irish Lighter Award, entries are encouraged from experienced lighting designers, or engineers who can present a paper about a finished project.

• There may be post-occupancy

evaluation evidence that is analysed critically and provides insight for the professional lighting community;

• There may be an innovative and/or

sustainable design that is at the industry cutting edge;

• Or it may be something worth

publishing that will be of interest, and benefit, to the professional community.

The Irish Young Lighter competition began in DIT in 2003 when the first students on the programme in Electrical Services Engineering graduated. Ken Winters was the inaugural overall winner and he then went on to represent Ireland at the international Young Lighter in London in 2004, where he won the Best Presentation.

Published research papers by winners of both the Irish Lighter and Young Lighter competitions may also feature in the SDAR Journal.

Who to contact michael.mcdonald@dit.ie or keith.sunderland@dit.ie

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IRISH LIGHTER AWARDS WINNER 2015

The Lighting of St Mel’s Cathedral

Mark Reilly Arup mark.reilly@arup.com

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Abstract The destruction of St Mel’s Cathedral by fire brought

1. Introduction

the local community together to fund its restoration.

There has been considerable interest in the lighting of cathedrals and churches recently, largely due to the necessity of renewing installations which were made in the early years of the century and are by now unsafe electrically, as well as being inadequate by present-day lighting standards.

Part of this initiative was the development of a lighting scheme using modern LEDs and intelligent lighting controls to recreate the atmosphere and reverence deserving of this historic house of worship.

Problems encountered associated with the age and style of the building to be illuminated are discussed in the paper. A description of the design process and methodology is also included, along with the appropriate lighting conditions necessary to emphasize certain architectural points. The paper covers the illumination of the cathedral for the 21st century by discussion of the methods used and the development of the design.

Key Words: Lighting, cathedrals, places of worship, LED, intelligent controls

More recently, the advent of new and more efficient light sources has led to some radical rethinking of the design standards possible, and, in addition, the liturgical reforms of recent years have led to the rearrangement of many interiors, necessitating alterations to existing lighting schemes.

Furthermore, the publication by the Society of Light and Lightings (SLL) Lighting Guide 13 (LG13) provided guidance on methods and arrangements of applying lighting. The lighting design of St Mel’s cathedral was already completed before the release of this guidance, therefore the design was scrutinised and evaluated against LG13(1). Some key differences emerged, including the recommended uniform lighting levels for the different areas within the building and the methods of achieving and controlling the lighting scheme suitable for such a building.

A number of factors enter into the design which are commonly found in other fields of lighting. However, considerations of the age and architectural style of the building, the proper balance between lighting to display architectural or archaeological features and for use during church services, and the daylight appearance were all taken into account.

The lighting scheme for the St Mel’s cathedral was sympathetic to the form, function and history of the building. The interior light scheme was designed for multiple light scenes according to the usage. Special attention was drawn to the method of installation of all new equipment and services routing.

The cathedral presented a number of challenging issues when developing the lighting design, some of them architectural in nature, others to do with how the building was to be used, and yet more focused on conservation, technology and cost.

High ceilings and obstructions, such as pillars and arches, all needed to be considered in terms of light distribution and liturgical items such as Stations of the Cross, statues and the baptismal font.

Soft, lighting accents emphasised the three-dimensionality of these items. Thanks to high positioning of the luminaires and glare reduction, visitors' enjoyment of art pieces is aided by high levels of visual comfort.

It was also important to apply the correct source of lighting so that a specified illuminance was accurately achieved as well as meeting the budget for the project. The success of the installation was not to be judged by light meters but through the eyes of those who have to perform the ceremonies as well as those who watch them.

Similarly, efficiency was not rated simply by the effectiveness of gathering all the lamp lumens and exclusively directing them onto

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Figure 1: The official reopening of St Mel’s Cathedral, Midnight Mass 2014.

Figure 2: Pre-fire condition of the cathedral.

the task plane, but rather by the ease with which the task can be seen and by the contribution of the lighting installation to making the environment more agreeable. This was achieved by careful commissioning of the lighting and creation of the different lighting control “scenes” with the St Mel’s Committee whose members included the local priests, key stakeholders and local engineers.

This insured that the lighting was adequate and operated for the tasks planned. However, the design intent was for a robust scheme that would mitigate any contract variations. Ensuring that the requirements of the client had been met required the addition of a small number of luminaires where an increase in lighting was deemed beneficial.

The lighting scheme was installed and the building reopened to the public in December 2014.

2. Background The cathedral is a neo-classical stone building, at the north east side of the town. Construction began in 1840 to the design of Joseph B. Keane and was finally consecrated on 19 May 1893. The cathedral is constructed like many churches in the shape of a cross.

Due to the cold, the heating ran at a high setting continuously for 17 hours on Christmas Eve 2009 to cater for the many visitors coming to say a prayer, light a candle or attend confession during the day and the for the large attendance at Mass that night. After Mass the temperature outside plummeted to -8°C. Sometime after 5am a local called the fire brigade and raised the alarm of a fire.

Despite efforts by the fire service, as Christmas morning dawned it was clear the interior of St Mel’s Cathedral was lost.

Figure 3: Post-fire condition of the cathedral.

The heating system consisted of an oil fired burner located in the crypt, with a flue connected to an original brick lined chimney. It is likely that combustible material may have accumulated in the chimney. Due to the prolonged running of the heating system, it is likely that this material became superheated.

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When the burner was switched off, the natural draught allowed the ingress of oxygen causing the combustible material to ignite in what was, in effect, a chimney fire. Unfortunately, this chimney was fitted with inspection hatches. It is believed that burning embers from the chimney fire escaped via an inspection hatch door in the sacristy. There it ignited some further combustible material which then spread to destroy the entire interior of the Cathedral.

3. Methodology The artificial lighting offered unique opportunities to integrate into its building fabric seldom possible in an existing place of worship structure. It cannot be emphasised too strongly how beneficial it was to discuss the lighting concepts with the architect at the earliest possible stage of the design of the building, and not leave it until detailed and finished drawings, which cannot be easily amended, were produced.

The advantages of designing the lighting at an early stage included simplicity in wiring and ease of maintenance, a point that is not always considered, but it is especially important in this situation where a regular maintenance staff are not employed(3).

The project was about marrying what was lost with what remained and putting in place something for the future. Historically, brass luminaires were mounted on walls and robust brass poles had been used to help illuminate the space. These were later refurbished with an LED source and reused as suspended chandeliers within the meeting rooms and the sacristy. Lighting of the cathedral space was a key area with modern technology used to visually enhance the cathedral.

Since St Mel’s cathedral differs greatly from most secular buildings both in its use and architectural design, the lighting installation could not be designed on the conventional lines of a traditional workspace as it also had to be flexible to fulfil a number of purposes.

One aspect which was carefully considered was the balance of dramatic and utilitarian lighting. For cathedrals a “numinous” atmosphere which is conducive to worship is required(2). This can often be achieved by dramatic lighting of the sanctuary, although it must always be remembered that the ambo and altar positions located within the sanctuary must have sufficient and suitable light for reading.

Regarding the visual task that would be undertaken by the congregation in the pews, they tend to sit in one particular area and this was to be a focus of the design brief. In addition to task lighting, this particular light is required to reveal texture and improve the appearance of the people within the space; thus good visual communication and recognition of objects within the space was essential. The average (mean) cylindrical illuminance was designed to be 50 lux, and uniformity (min/average) over 0.1, calculated 1.2m above the floor level. Each of the directional luminaires providing the functional lighting in the space was carefully angled towards the rear of the nave; this allowed the cylindrical illuminance required to be achieved.

36

Subtle emphasis of architectural features was also considered to help achieve the required atmosphere, but care was taken not to light a cathedral merely to show off its architecture. Indeed, the lighting design concentrated on creating contrasting effects since it is difficult to light a building by artificial means to give the same effect as is seen by daylight but to maintain the buildings functionality(4).

The lighting brief was to bring the 19th century building into the 21st Century. This included a lighting system that was to be energy efficient but would also capture the atmosphere essential to the cathedral. The level of control and scene-setting would also allow the priests to pre-set specific lighting scenes for specific liturgical occasions.

The lighting had four objectives: – to enable participants in the religious activity or ceremony to see what they are doing; – for the congregation to see what is happening around them by providing horizontal illuminance (maintained 100-150 lux) and cylindrical illuminance (50 lux) on the pews measured during commissioning using lux meters; – to contribute to the safety of everyone within building; – to create a good visual environment.

4. Spotlights or pendants The use of pendant luminaires, either in the form of branched candelabra or of individual lamp housings mounted on a hoop or hoops, is often recommended, especially in the nave. The theory is that they more closely resemble the sort of lighting that may have been originally installed and that they have some decorative value in their own right. Such a system has the advantage of providing adequate illumination at “prayer-book level” economically, but it can give rise to considerable glare and also cause a ‘tunnel effect’ unless the fittings allow some upward light on the vaults. There is, however, considerable force in the objection that they are out of place in an environment that was never designed to take them, and that in daylight they ‘pollute the space and spoil the appearance of the building(5).

The alternative of spotlighting using an LED source was used for St. Mel’s cathedral but it was not without its disadvantages as it required careful consideration of their placement so they could be discreet. The lighting equipment is usually unobtrusive by day, but at night banks of spotlights can be remarkably glaring and seriously interrupt the soaring vertical lines of the architecture. The optimal position found was on the tops of the limestone columns for projection of light onto the side aisle and on the above-the-string cornice for the central aisle. From a lighting perspective this method is normally not to be encouraged in most other situations due to the glare caused by luminaires at lower mounting heights.

However, as it was possible to keep the fixtures above 10m, the solution was both discreet and effective.

A recent departure used for the Cathedral, made possible by the high-efficiency LED lamps now available, is indirect lighting of the

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contrast between the illuminated and unlit parts of the cathedral produced dramatic effects without apparent effort.

Picking out salient features in daylight by means of carefully placed spotlights is equally permissible, and can give the effect of shafts of sunlight if carefully done. The concealment of the equipment has been made easier by the introduction of very compact narrow beam spotlights.

7. Design concepts

main barrel ceiling from uplighting projectors mounted on the string cornice, but this necessitates supplementary direct lighting for the congregation to be able to see and read. As the aisles are also lit in this way, a fairly close approximation to the daylight distribution of light in the building was achieved.

It was immediately apparent that the “lumen method” of lighting design, intended to produce an average maintained illuminance over an area, could not be applied to this building. Certainly, enough light to allow priests, choir and congregation to read easily is necessary, and the recommended illuminances in the LG13 code should be adhered to, but a flat, even distribution of light is neither necessary nor desirable.

5. Lamp source

It was equally obvious that with the exception of decorative chandeliers the lighting equipment should be as unobtrusive as

With the reducing price and increasing availability of good quality LED spot and floodlights, they were considered as a first option.

They provide a good low-energy solution with a very long life, thus reducing the need for maintenance access to what is a high location(6). The wide availability of LEDs with different beam angles means that one family of fittings provided light for many different purposes. Wide beams were used for washes over vaulted ceilings, medium beams for lighting down over seating areas and narrow beams for picking out altars or features in the space. The LED spotlights came with integral dimming with DALI (digital addressable lighting interface).

Figure 6: Functional lighting concept.

Figure 4: Discreet positioning of the luminaires was key.

6. Highlights and Shadows It was important that glare was avoided wherever possible. A common fault is glare caused by an array of spotlights at low level or aimed without care from the cornice.

Glare was not simply a matter of the intensity of the light source; it is related to the contrast between a lighted object and its background. The illumination of the ceiling helped to counteract this issue.

This does not mean, of course, that a bland shadowless effect was the aspiration. The modelling of shafts and pillars, arches and sculpture was essential as their form was to be perceived. The

Figure 7: Accent lighting concept.

Figure 5: Vertical illuminance on the Stations of the Cross.

Figure 8: Uplighting concept.

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possible. These buildings traditionally were not used after dark by the laity and, apart from the dim gleam of sanctuary lamps before the altars, the rest of the church would be in darkness. Even in parish churches the custom of a late evensong is comparatively recent, dating only from the 19th century, so that any form of artificial lighting is bound to be out of character with its surroundings. However, lighting essential to the present use of the building and the advent of first gas and then electric lighting in the l9th century has accustomed people to its use.

The lighting of some areas had been varied to suit their use; for example, as the nave was to be used for worship, lighting was concentrated on this area used by congregation and on the altar with the rest of the building left in comparative, although not absolute, darkness. In contrast, when used during the day for visitors or quiet reflection, less light is needed on the seating, and architectural features were emphasised, with indirect lighting of the ceiling vault, and some lighting in the organ and architectural elements.

Based on the objects, the lighting concepts focused on how and what elements required illumination. These main concepts included: – the function lighting on the horizontal plane by wide beam projection LED luminaires at the tops of columns; – accent lighting of the key architectural elements and art pieces by discreetly located LED projection lighting; – uplighting of the barrel ceiling which would highlight the great craftsmanship put into the plastering detail.

8. Areas requiring special lighting Organ and choir: Light for reading music was a vital element for the cathedral. A technical problem was that organ furniture was dark and absorbs light while choristers using sheet music look at music on a white background. To light the choir area, individual luminaires were recessed within the choir stall which provided functionality without taking away from the overall feel of the space.

Altar and ambo: The altar is the focal point of the cathedral; it is also a centre of worship, the table on which Holy Communion is celebrated. It must therefore be illuminated dramatically, but not in such a way as to make it difficult for the priest to see both his Bible and the congregation.

The readers at the ambo not only need to be able to see what they are reading, but must themselves be visible, for a great many elderly and deaf people rely on lip reading or on the facial expression as well as the sound of the readings.

The use of a strip light mounted at the top of the reading area also has serious disadvantages. Reversed shadows on the reader’s face can have a negative effect on their appearance and a further disadvantage is that, if the strip light is mounted too close to the surface of the desk, it may cast shadows across the page making it difficult to read(7).

38

Figure 9: The Ambo during commissioning of the lighting.

The solution implemented was to provide dedicated spotlights with carefully shielded lamps to light the book or typescript. The spotlights were mounted 12m high and to the sides, so as to avoid glare and shadows to the reader, and to give natural modelling to the persons face.

9. Emergency lighting The actual placing of luminaires presents the greatest difficulty rather than achieving the lighting requirements indicated in IS 3217 Code of Practice for Emergency Lighting with a recommended average maintained illuminance at floor level of at least 0.5 lux along the centre-line of the gangways. The main emergency lighting arrangement internally included recessed emergency lighting “nodes” in the side aisles and projector versions of these miniature nodes adjacent to the array of spotlights on the string cornice in the central nave(8).

The choice of system was mainly between a centrally controlled system, in which all the luminaires would be fed from a central point, using a large storage battery, and one of self-contained luminaires powered by nickel-cadmium cells actuated by mains failure. The former solution was implemented as it reduced the risk of battery failure at the lamp hence decreasing the amount of maintenance required at heights(9).

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10. Methods of calculating lighting values The modelling and calculation used throughout was by the Relux Pro lighting software. Working with a 3D model enabled the discussions with the architect to be more productive and efficient, clearly indicating the intent and assisting with the design development.

The need for modelling and the provision of a “numinous” atmosphere governed the placing of the lighting equipment and the direction of the light. There is always a certain amount of “spill light” in the beam of a spotlight so that a certain amount of ambient light will be present on vertical surfaces, but it is important to provide variations of brightness. Therefore, carefully calculated positioning of the lighting equipment is recommended.

As a system of indirect lighting is used in the form of lighting the ceiling vaults, the reflectance of the vault or ceiling is of great importance. As it was a white plaster ceiling it reflects about 70%

Figure 13: Design lighting levels taken from the lighting software.

Figure 10: Modelling of thelLighting taken from the lighting software.

Figure 11: Rendered view taken from the lighting software.

of the light falling on it, but a stone vault as per the crypt would reflect no more than 50% at most(10). As the ceiling is intersected by ribs, this figure would be still lower. Consequently, the indirect lighting of the vaults was not expected to provide a significant proportion of the light at ‘prayer-book level’, and the need to supplement it with direct spotlighting was imperative. The indirect lighting component was effectively no more than a decorative element especially when the number and power of direct lighting units was calculated but, nevertheless, uplighting of the vaults does produce ambient lighting needed for casual perambulation of the building.

If it was simply a matter of providing the recommended illuminance on the bible, choir or congregation, the reflectance of surfaces is of course irrelevant. However, it was important in calculating the size of the lamp and type of reflector to light vertical surfaces and the underside of the ceiling.

LG13 was not released during the design, therefore similar examples had been used as benchmarks as well as the illuminance recommendations for similar applications indicated in the SLL code for lighting 2012. The illumination on the horizontal plane in various parts of a church was designed to 100 lux in the “body” of the church, and 200 lux within the sanctuary with further accent lighting where required.

Figure 12: Lighting installed and operating.

It transpired that the recommendations given with LG13 were consistent with the design approach(12). However, the design did not include for the recommended maintained horizontal illuminance of 500lux for the altar area. The design approach was rather less uniform and focused more on making the altar the focus

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of the building with lighting but by using accent and vertical lighting as well as a base line 200lux of horizontal illuminance. This was achieved by using different ‘layers’’ of light which include uplighting of the alter back wall and dedicated accent lighting of task areas such as the ambo and the bishops chair so that reading can be achieved during services without issue.

11. Lighting controls The key client aspirations for the lighting control system were flexibility, ease of use and energy efficiency.

In order to deliver on this ambition, an intelligent control system using DALI (Digital Addressable Lighting Interface) was installed to enable a variety of fittings and controllers to be integrated within a single control system. The dimming system allows simple changes in the feel of the space, from simple lighting for general use to higher levels for services, with special scenes reserved for weddings, High Mass or quiet reflection.

The scene settings activate and/or dim specific light fittings and harnesses natural light when available to reduce energy consumption. The system also provides status reports for the user and allows remote access to the lighting system.

The centralised lighting control system with pre-set scene control makes it easy to set and change the mood for any activity at the touch of a button. The touch screen panel allows for the priest to select up to 12 different lighting scenes within the main sacristy.

Figure 14: Commissioning of the lighting controls.

11. Discussion For specialist designs such as this, it is imperative that early coordination and agreement of the lighting concepts are carried out with the architect and client. The levels of illuminance, lamp source and controls are important but the visual effect on the space was the most critical factor on this project.

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Many of the design fundamentals have been highlighted with the SLL’s Lighting Guide 13: Lighting of Places of Worship which provides up-to-date guidance where relevant and incorporates best practice principles throughout, including the introduction of a distinction between task area and surrounding areas, and the subsequent recommendation of uniformity for those areas.

However, uniformity is an issue that requires careful consideration as a less utilitarian approach was achieved with St Mels Cathedral.

The approach here provided a more dramatic result while keeping the building functional.

Further evaluation of how the lighting has been adapted and controlled by the sacristan and priests, particularly with regard to the scene setting and the relationship between energy consumption and providing a decorative scene suitable for the different situations would be desirable. However, that was not part of this paper and would be recommended for future research.

References (1) SLL (2013) Lighting Guide 13: Guide to places of worship (2) Inter Faith Network for the UK (2010) Building good relations with people of different faiths and beliefs (London: Inter Faith Network for the UK) (3) CIE (2005) CIE 097:2005: Guide on the maintenance of indoor electric lighting systems (Vienna: CIE) (4) IS EN 12464-1 (2011) Light and lighting. Lighting of work places. Indoor work places (5) SLL (2013) Lighting Guide 10: Daylighting and window design (6) IS EN 15193: 2007: Energy performance of buildings. Energy requirements for lighting (7) Boyce P R (1981) Human factors in lighting (London: Applied Science Publishers) (8) IS 3217: 2013:Code of practice for the emergency escape lighting of premises (9) SLL (2004) Lighting Guide 12: Emergency lighting design guide (10) SLL (2012) The SLL Code for lighting

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The Pavilion of Light, Mardyke Gardens, Fitzgerald Park, Cork

Stephen Robinson stephen-t.robinson@arup.com

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Abstract This paper describes the lighting design and rationale for the Mardyke Garden project. It is realised through accentuating the historic buildings and integrating the local biodiversity issues such as the park’s bat population. Many new modern structures have been added to this historic park such as a pavilion bandstand, called the “Pavilion of Light”, with colourchanging luminaries and in-ground, star-scape, fibreoptic lighting in the children’s play area.

This paper discusses the background behind the final lighting design and how integral elements such as the walkway bollards were designed so that bats would avoid the area involved, thereby sustaining their participation in the local ecology. Furthermore, the bandstand is now used as a reflector that not only changes the colour of the stage but as a projector into the sunken garden, synergising performance with the experience of patrons.

Also discussed will be how the lighting designer drew from localised landscaping in maximisinging optimal experience. Lighting controls are also discussed. Cork City Council can now manage this complex lighting design so that patron’s experiences can evolve based on multi-faceted elements such as season, event and even occasion.

Key Words: Innovative lighting, colour-changing lighting, LEDs, ecological friendly lighting.

1. Introduction The redevelopment of Fitzgerald’s Park has created a state-of-theart public facility in the heart of the city. The thoughtful reimagining of the space, driven by the relocation of the bandstand to the front lawn, was integral to the success of the scheme and of reinventing the park. The Pavilion is now a modern landmark, conjuring memories of the grand bandstand of the international exhibition held at the site in 1902. Its success has acted as a catalyst for community engagement and has facilitated a range of events enjoyed by locals and tourists alike. As an icon of collective memory, it forms the heart of a wider community, designed to serve diverse ages and interests. It is a wonderful facility, whose flexibility of use will attract visitors from near and far for years to come as the park evolves and grows.

This paper discusses the lighting design of the Mardyke Gardens and covers many aspects of outdoor lighting. The bandstand is uplit with RGB LEDs to allow automated colour change of the Pavilion, which can subsequently be reflected onto the garden performance viewing area because of the reflective nature of the Pavilion. The walkway lighting is designed to be low energy and architecturally coherent with the surrounding design. The children’s play area features fibre-optic lighting in the ground to form a “Starscape” at night and the POD, which was originally Dermot Gavin’s awardwinning Hanging Garden at the Chelsea Flower Show in 2011, is now fixed firmly to the ground. Mounted on a podium, wide angle low-level luminaires illuminate this structure from below to accenuate the elevated “floating” POD effect.

The controls bring all of these separate lighting aspects together into one coherent design. The lighting controls use manual and Dali devices, along with an astronomical timer and web app facilities to ensure maximum flexibility of when and where these luminaires can be controlled or configured. This gives the City Council great scope to adapt and adjust the lighting design to suit the current need within the spaces.

The need to create an effective design in harmony with the existing environment was a key part of this project and introduced some challenges with regard to a local bat roost.

The complexity of working with bespoke structures provides challenges when attempting to calculate or model such areas. Parts of this lighting design did not rely on calculations but rather the experience of the designer. These challenges are also discussed within.

2. Background The Mardyke Gardens was founded in 1845 by the building of Shrubbery House on its land by local brewer Charles Beamish before being bought by the Bon Secours Sisters in 1861. In 1902 it played host to the International Cork Exhibition for more than a year. Once the International Exhibition was finished, the park was handed over to the corporation for the people of Cork with Shrubbery House later becoming a Museum in 1942. Since then the citizens of Cork have enjoyed walking through the park and enjoying the gardens. In 2011 Cork City Council and Failte Ireland

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The Pavilion of Light, Mardyke Gardens, Fitzgerald Park, Cork

3. Methodology The objective of the lighting design was primarily to improve the experience associated with the architecture and to carry this heightened experience into the evening and night for the occupants of the park. This was broken down into four main areas of light.

Figure 1: Pavilion of Light and front lawn with the Museum in the background leading to the Gallery Garden.

Firstly, the Pavilion of light is a bespoke structure with smooth curves and high reflectance to enhance acoustic performance of bands playing by directing sound outwards towards the front garden. The objective was to use this structure to enhance the visual experience also by using the white surface as both a canvas and a reflector. The challenges this posed was the fact that it was such a complex structure that modelling it or calculating it would not prove to be an accurate estimate. The design was largely based on manual estimations and mock-ups on site.

The second lighting task was to highlight some of the new trees planted in the garden. For this, narrow beam LEDs are used with a 40° cut-offf to ensure only the targeted tree is illuminated.

The third area of interest from a lighting design perspective was the children’s play area. This area is open-plan between the POD and the museum with a clear canopy structure located within it.

Fibre-optics are used to create a starscape in the ground which can twinkle in the dark, replicating the night sky on the ground.

Figure 2a: Walkway, Gallery Garden, POD and Landscape Spheres.

The fourth area of interest was the POD, located at the rear of the park beside the children’s play area. The POD was originally suspended from a crane at the Chelsea Flower Show but, as this could not be replicated in a public park, the POD was mounted on a podium. The lighting design in this area was designed to illuminate the POD from below to highlight the structure without

Walkway

Pavilion of Light

Manual control dimming Astronomical timer Scene setting Colour control Web App control

Starscape

Figure 2b: Children’s play area with clear canopy (above).

agreed to fund a renovation of the park and to focus attention on two separate areas;

Uplighting

(1) Relocating the bandstand and creating a new pavilion in front of a viewing lawn to facilitate public access to numerous stage performances throughout the year;

Figure 3: Design approach incorporating control elements for each facet of the project.

(2) The addition of the POD in the Gallery Garden overlooking the river Lee to the rear of the park with a new walkway linking it to the main entrance. The Gallery Garden area also includes a new children’s play area in and around new and exciting landscape spheres (Figure 2a and Figure 2b).

attracting emphasis on the mounting. This approach provided the illusion (at night time) of a floating structure as the light shining beneath it was evenly distributed along the front of the object and its linear length. The podium it was mounted on was not the focus of illumination.

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Finally, the walkway from the main entrance to the POD and surrounding areas was designed to ensure adequate light to pedestrians walking through the park, but also to not interfere with the local bat population in the park. Cork City Council required assurances that local bat life would not be effected by the lighting in all of the circulation spaces that the public would frequent. The design approach is illustrated in Figure 3 (page 45).

3.2 Up lighting of the new horticulture As part of this project many new trees and foliage were planted and the landscape architect wished to highlight some of these at night time. To do this, in-ground IP67 LEDs with a colour temp of 3000K were used. In order to limit upward light pollution a narrow beam angle of 40° was chosen (Figure 45). The lamp was also recessed down inside the fitting to limit glare to pedestrians.

The four separate aspects of the design were all integrated onto a common control platform (Philips Dynalite) that brought together control protocols; such Dali protocols outlined in IEC Standard 60929 are used for dimming and switching, and DMX controls for colour-changing to DMX 512. The control strategy developed ensured all the above criteria were met. It also complemented the vision of the new landscape architecture.

3.1 The Pavilion of Light The Pavilion of Light is illuminated via nine 900mm-long in-ground asymmetric RGB (18W x 3) LEDs spaced evenly across the underside of the structure. The structure is white, giving an accurate reflection of the light being directed towards it. The Pavilion reflects the light outward onto the front lawn giving a spectacular light show each night. The luminaires are Dali controlled from within the museum and are set on the colour-changing loop each night. The colours and sequence can also be controlled via Cork City Council’s office, or from an iPhone/Android app. This allows the bandstand to change to any colour of the spectrum at anytime from anywhere.

Figure 5: Narrow beam angle of uplighter.

Figure 6: Narrow beam uplighters focus light on trees and limit upward glare.

3.3 Starscape The Starscape is located in the children’s play area of the park. The idea behind this is to create some in-ground lighting that would

Figure 4: Pavilion of Light (top) and some spot lighting highlighting new trees (below).

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Figure 7: Starscape employing bespoke sculpture as well as shrubbery in the cobble lock area.

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The Pavilion of Light, Mardyke Gardens, Fitzgerald Park, Cork

add a sense of fun to the space. The light engine was located in a dry enclosure hidden within the new shrubbery and the light was carried by sheathed end–emitting polymer optical fibre. These fibres were located within the cobble lock of the play area.

3.4 Walkway Lighting The walkway from the main entrance of the park to the rear (towards the POD) posed some concern to Cork City Council as a known bat roost was in the area. The walkway lighting was designed to ensure the bat flight pathways between the roost and the river Lee where unaffected.

To achieve this it is important to understand what effects bats and their feeding habits with regard to the surrounding light.

Bats are nocturnal and only come out at night after the sun has set and light levels are low. Most bat species are photophobic and bright lights near or around a bat roost have been known to impact the population in the area. “The direct and artificial illumination of a bat roost area may reduce activity resulting in later emergence, giving bats less time to forage which may result in bats being underweight, thereby increasing the risk of mortality during winter hibernation (Bat Conservation Trust, 2009)”.

Light emitted at one wavelength with no ultraviolet light helps to maintain the bats’ environment as normal. Low temperature luminaires are recommended for use in areas of known bat activity due to the low levels of UV emitted. Light at this colour temperature does not attract insects and thus does not interfere with the bats usual feeding habits.

It is also recommended that lighting in these areas be kept low and focused on the task area to minimise light spill. The UK bat organisation recommends that luminaires should not exceed eight metres tall and that a 10-metre corridor adjacent to the illuminated area should be maintained to allow bats to travel in parallel.

Figure 9: Dialux calculation to achieve 10 lux average if required, luminaires are running at 50% of this value on site.

After occupied hours the luminaires, which are controlled via an astronomical clock, ramp down even further to give a 3 lux average. This is to further improve the bats’ night time environment and also not to attract unwanted anti-social behavior. The bollards are IP67 and IK10 which are particularly suited to this project.

Under CIBSE Guidelines (CIBSE, 1991) 10 lux for primary pathways and 5 lux for secondary pathways in public parks is required. The lighting calculation was designed to meet the 10 Lux but, as the luminaires were dimmable, a derogation was allowed by Cork City Council to designate this pathway a secondary route and the luminaires’ outputs were dimmed down to meet this requirement.

3.5 The POD

For this project, 1-metre tall LED bollards were used with a colour temperature of 3000K. The light level on the pathway was kept to the required minimum of 5 lux. This was achieved by specifying dimmable luminaires and physically calibrating (dimming down) each one in position to gain the correct minimum light level, and to eliminate any unnecessarily high levels along this pathway.

The emphasis on lighting the POD was to evenly distribute the light across the front of the POD but, at the same time, to ensure the mounting platform stays in some darkness. To do this wide-angle luminaires were positioned at each end of the structure, mounted slightly in front and hidden from view behind some shrubbery. The luminaires adequately light the structures’ façade facing the occupants of the park and do not highlight the mounting brackets underneath.

Figure 8: Bollard lighting model – 10m bat corridor to the right, low level direct light on the pathway at 300K minimises the impact on the bats’ habitat.

Figure 10: The POD illuminated by wide angle floodlights at each end from below.

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5. Discussion This lighting design had many challenging aspects, most notably the local fauna. This was successfully overcome with the use of 3000K low UV output lighting mounted at one metre from ground level. The selection of the LED bollards not only fitted well with the architectural landscape furniture, but also allowed the light to be distributed at low level under the recommended guidelines, and within the 5 lux maximum level. The use of an astronomical timer ensured the luminaires were only on for the minimum required duration.

At the beginning of the design stage the Pavilion represented a large unknown as this was a bespoke structure. The lighting design for this object developed with the pavilion design and turned out to be very effective and achieved its objectives. The use of cloudbased Dali controllers ensured full adaptability for the Pavilion to change colour and output levels easily to suit any band/stage act.

References Bat Conservation Trust. (2009, May 01). Bats and the Built Environment Series. Retrieved September 01, 2015, from Bats & light in the UK: http://www.bats.org.uk/data/files/bats_and_lighting_ in_the_uk__final_version_version_3_may_09.pdf BSI. (2013). BS 5489-1:2013 Code of practice for the design of road lighting. Lighting of roads and public amenity areas. London: BSI. CIBSE. (1991). Lighting; The outdoor environment. London: CIBSE. Commission, I. E. (2014). IEC 62386. IEC. International Electrotechnical Commission. (2014). IEC/PAS 62717 LED modules for general lighting – Performance requirements. IEC.

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