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Climate Change Adaptation Research Technologies Strategy Board (TSB) Passive Office Study Tour, Portugal April 2012 Notes

Gale & Snowden Architects & Engineers April 2012


Gale & Snowden Architects

Notes from Passive Office Study Tour, Portugal

Passivhaus Study Tour Portugal, April 2012 Notes Prepared by:

Jason Fitzsimmons

Checked by:

David Gale

Project:

PassivOffice

Version:

1

Date:

April 2012

Job No:

B1113

Reference:

B1113 CCA Passive Office\Reports\Passive Office Portugal Study Tour Notes

Rev No

Comments

Date

Gale & Snowden Architects Ltd 18 Market Place Bideford Devon EX39 2DR T: 01237 474952 F: 01237 425449 www.ecodesign.co.uk Company No. 5632356 VAT Registration No. 655 9343 06

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Notes from Passive Office Study Tour, Portugal

1.0 Introduction The following details the findings and observations from the Gale & Snowden Passive Office visit in Lisbon Portugal of the Solar XXI building.

2.0 Details of the Passive Office Building name: Solar XXI and is the National Laboratory of Energy and Geology (LNEG) Completed:

2006

Floor area:

Total: 1500 m2, useful 1000 m2

Building type:

Offices and Laboratory

No of Floors:

4 including a basement

2.1 Key features The building has been designed with the following key features: Natural ventilation – with cross flow, stack and single sided ventilation with high and low level openings – all manually controlled. Glazed louvres above doors enabled air to move from the office space into the stack corridor. Central full height corridor throughout the building with high level stack openings Stairwells at either end of the building on the east and west side, both of which have high level stack openings Thermal mass in solid floor and internal walls. Walls consisted of an external wall insulation system. Innovative use of mass in the floor with a channel for floor services. South facing orientation – maximising solar gain in winter with large south facing double glazed units Integrated vertical PV system on the south facing façade with innovative heat recovery from behind the PV panels to the office space via high and low level openings. Additional pitched PV system in the adjacent car park area. Solar hot water panels on the roof for pre-heating a thermal store for heating only. The building has no hot water supplies. The design featured 32 x 300mm diameter concrete earth tube system ranging from 5-15 metres in length at a depth of 4-5 m in the ground. During elevated internal temperatures the fans were switched on to pull air through the ground to help cool the space.

2.2 Thermal Details Windows:

Double glazed units with a Uvalue of 2.6 W/m2/K. External shading to control solar gain in summer.

Walls:

220mm masonry brick internal, 60mm EPS insulation external – Uvalue 0.26 W/m2/K

Floors:

Concrete and screed on top of 100mm EPS insulation – Uvalue unclear

Roof:

Concrete with 100mm EPS on top - Uvalue unclear

Air Permeability: Untested due to warm winter conditions and Portuguese building regulations

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Other features:

Notes from Passive Office Study Tour, Portugal

The vertical south facing faรงade consists of 100m of PV to the external wall. This is claimed to protect the fabric from solar gain in the summer and also retain heat loss in the winter. Designed and built with high internal thermal mass and external insulation to stabilise internal temperatures and to support night cooling.

2.3 Ventilation Systems The ventilation systems relied on manual control and a good user understanding of when and how to operate them as there were various control parameters. The occupants were energy engineers and building physicists, i.e. highly skilled technically minded occupants. How easy this strategy would be implemented in offices with less technically minded people would have to be considered. The system relied on occupants to control solar gain manually via the external blinds, open and close various vent openings, manually switch on ground cooling. Ventilation control parameters: o

In winter open both internal high and low level vents and close off vent opening externally to the PV shaft. This creates a recirculatory air system partly heated via solar gain on the PV panel. Fresh air would then be via the opening window. This is provided that there is solar gain in the winter on the PV panel. If there is there would also be solar gain through the glazing providing useful heat to the space.

o

In winter open high level vent internally and external low level vent to PV shaft to drive pre heated air into the space during periods of solar gain.

o

In summer close high and low level openings internally, open both high and low level openings to external PV shaft to vent behind PV panel.

o

In summer opening windows, open louvres above corridor doors and open roof level stack openings.

o

During elevated summer temperatures enable ground cooling system

o

In summer night cooling - open high level vent internally and external low level vent to PV shaft to drive air into the space. Keep stack vents open. This provided a secure night cooling natural ventilation strategy.

o

Night cooling could be boosted by earth tubes and enabling fans.

Earth tube system The potential issue of condensation forming in the duct and/or bacterial contamination had not been considered. It was found that even when the fans were not in operation air was moving through the duct into the building under natural driving forces. This was because there was no means for closing the system off in an air tight manner when not in use. There could be certain times in the year where condensation could form on the inner walls of the earth tube. There appeared to be no means to drain this if it did occur. The fans to pull air through into each office space were located within the offices; this presented a potential noise issue when in use.

2.4 Overheating Monitoring of internal temperatures (see paper Solar XXI Toward Zero Energy) revealed that for 95% of the time internal temperatures did not exceed 27 0C. This paper does not reveal the occupancy patterns during the study and it was unclear at the time of the visit as to whether the

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Gale & Snowden Architects

Notes from Passive Office Study Tour, Portugal

building was in full use. If fully occupied with people and PCs internal temperatures may differ to what has been revealed. Sufficient strategies had been designed into the building with good use of cross flow and stack ventilation, mass for night cooling, control of solar gain and ground cooling to enable the building to operate passively without air conditioning. In terms of design the building had large glazed areas facing south and issues associated with overheating were addressed by good solar control which was via external retractable shading on windows with high solar gain.

2.5 Daylight and solar orientation Internal corridors were well day lit from the roof glazing system and did not rely on artificial lighting during the day. The roof glazing was north facing. Solar orientation - the building had been laid out to optimise solar gain in winter and windows on these elevations were generous to allow this. The key to ensuring that the building did not overheat in summer was solar control, which was via external retractable blinds and overhangs. This is an important element for climate change adaption work as it shows that passive ventilated offices in warmer climates with large southerly glazing can and does work without air conditioning. With blinds 他 down the offices spaces still enjoyed very good daylight levels and did not rely on artificial lighting. This was observed on a sunny day and it is to be noted that Portugal enjoys better and higher external light levels than the UK. In a UK context with blinds 他 down internal daylight levels might not be so high.

2.6 Design for Future Climate (D4FC) Adaptations From a D4FC adaption perspective the Solar XXI building has been designed passively on the current weather files for Lisbon, Portugal and the design did not take into account future climate change in the same manner as this project. The weather file that would have been used is one that has higher air temperatures than the UK and exceeds a UK future weather file of 2080 50th percentile. See Figure 12 at the end of this report. The office did not have air conditioning and was designed and orientated to optimise solar gain in winter with large glazing areas in a southerly direction. Overheating was controlled through various strategies which all worked in conjunction with each other - manually controlled ventilation openings, the use of thermal mass and night cooling, solar control via external shading. Ground earth ducts were enabled during hotter conditions.

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Notes from Passive Office Study Tour, Portugal

2.7 Images Figure 1: South Facing Facade showing vertical PV array, glazed areas and external blinds

Figure 2: Close up of high level opening

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Figure 3: Vertical PV detail with external high and low level openings

Notes from Passive Office Study Tour, Portugal

Figure 4: High and low level internal openings where PV is located externally.

Figure 5: Stairwell high level actuated openings for stack vent

Grey shutters are the vent openings to the inside and are operated manually. The white bars are pulled to open the external PV shutters or pushed in to close them.

Figure 6: North faรงade glazing with high and low level openings

Figure 7: Fan systems for earth tubes

These were located in the office space and covered by a panel when not in use. Air movement was felt from the earth tube when the fans were not switched on. The fans emitted noise direct in the office space when switched on.

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Figure 8: Glazed ventilation openings from office rooms to corridor to enable stack ventilation. There is no acoustic attenuation.

Notes from Passive Office Study Tour, Portugal

Figure 9: Glazed ventilation openings from northern office rooms to corridor to enable stack ventilation and allow daylight penetration from roof north lights. There is no acoustic attenuation.

In the northern rooms these were much larger to allow for better daylight penetration as windows in the northern faรงade were small than on the southern facade.

Figure 10: Eternal intakes for Earth tubes

April 2012

Figure 11: Channel in floor for services to maintain mass in floor and heavy weight construction

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Notes from Passive Office Study Tour, Portugal

Figure 12: Lisbon current summer weather file vs UK 2080 50th percentile

Lisbon weather file, no of hours external air temperature is above 250C = 878 hours UK weather file 2080 50th percentile, no of hours above 250C = 502 hrs

Green = Lisbon Red = UK 2080 50%

April 2012

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Profile for Jonathan Barattini

G&S Lisbon Passivoffice Study Trip Notes  

Notes from Gale & Snowden's study trip to Lisbon as part of TSB work, designing for future climate.

G&S Lisbon Passivoffice Study Trip Notes  

Notes from Gale & Snowden's study trip to Lisbon as part of TSB work, designing for future climate.

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