Zero Energy Buildings - AAU course

Renovation of the Skovgårdsparken Complex Piotr Zbierajewski Msc 02 ARC 2016 Aalborg University

Course: Zero Energy Buildings Period: 1. February - 19. February Semester: MSc 02 ARC Teachers: Anne Kirkegaard Bejder Lars Brorson Fich, Kemo Usto Isak Worre Foged, Claus Kristensen Lasse Engelbrecht Rohde Jerome Le Dreau Anna Joanna Marszal Mary-Ann Knudstrup Tine Steen Larsen Michael Lauring Mads Dines Petersen Hans Bruun Olesen Rasmus Lund Jensen Olena Kalyanova Larsen Shelley Smith, AD:MT - Urban Design (URB) Mads Dines Petersen - AD:MT Architectural Design (ARC) Kaare Eriksen / Finn Schou, AD:MT – Industrial Design (ID) Number of pages: 16 Number of pages with asignment: 12

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Introduction This work contains proposal for the renovation of the building „I” from Skovgårdsparken housing complex in Århus, Denmark. Report was done in a response to the assignment given during Zero Energy Building (ZEB) course. Intention of the project was to transform existing building from the complex into nearly zero energy building into one meeting the regulations of Danish energy frames for building class 2020.

Location Skobgårdsparken housing is located in far western part of Århus. It contains 20 buildings containing 367 apartments (Brabrand boligforening, 2016). By avarage each apartment contains 2,5 persons (Aalborg Universitet, 2016).

Methodology This research used integrated design processes and Probem Based Learning (PBL) as a main tools to fulfill given asignment.

Work consisted use of the Building Information Modeling (BIM) and energy evaluation software. In last case data were simulated on: • BSim - Danish building simulation program which was used for calculating influences on residents’ atmospheric and thermal comfort.

• Be10 - another Danish building simulation program used for the simulation but used for calculating whole buidling’s energy consumption (with 2020 class index).

The complex Most of Skovgårdsparken housing complex was build between 1960 and 1967. During that time some building went through different changes - mainly by changing the flat roof into slopy one. Condition of the housing were getting poor and poor as the time has passed - mainly because original materials and technologies used in 60’s were very cheap. Because of this buildings have struggled with many thermal and quality comfort issues.

Right now it is a mix of social housing as well as the students’ apartments. One of the big issues of this complex is that it was build quickly with use of the cheapest technologies of its time.

Current situation Skovgårdsparken is under extensive renovation since 2011. It is a pioneering project, with a resulting reduction in energy consumption of 90%, sets new standards in energy and sustainability and therefore it has won the renovation price 2013 (Wikipedia 2016).

For the use of this raport futher expression „existing building” will mean condition of the building from before year 2011.

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Existing building • •

• • •

Building „I” from Skovgårdsparken complex is facing few important issues: Cold bridges in the building envelope Large transmission loses due to the old and damaged insulations, single-layered window glazings and huge areas of cold-material window frames. Losses are also made by the roof which is not insulated at all No input from mechanical ventilation Poor venting Space heating and domestic hot water installations are not insulated which causes additional heat loss.

The most critical apartment was taken into futher considerations which is the most north one on the top (third) floor.

Ill. 1. 3D model of the „I” building from Skovgårdsparken complex

Ill. 2. Floor plan showing most critical apartment

This apartment is having heat loses through three exterior walls (from west, north, east) and through the roof. Futher work consists analyzing and solving problems of this housing unit.

Submission's requirements demanded thermal comfort classification 2, suited for normal level of expectation for new buildings and renovations (EN 15251:2007 standard) and indoor air quality classification 2 (CR1752 standard). For easier calculation input nuber of people living in one apartment was 3. Energy neutrality including the energy use for appliances and lighting, which cannot be higher than 1725 kWh/year per apartment (it corresponds to a heat gain of 1.71 W/m²) (Aalborg Universitet, 2016).

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First Be10 simultion (fig. 3) has showed that Total Energy Requirement (TRE) = 188,2 kWh/m² per year.

It was clear that the building was using almost all the energy on heating. The results from BSim showed that the request for heating was coming from the large transmission loss. What is more there was a critical number of hours above 26°C and 27°C (during the summer) as well as too many below 18°C (winter) causing a poor thermal comfort in the apartment (fig. 4).

Be10 by default is showing yearly analysis with option to change it to monthly data. However daily simulation from BSim has showed how the temperature is behaving inside chosed apartment throughout the whole day with detailed hourly report. (fig. 5) . Of course heating was not the only one concern. The problems were also the overheating during the summer and ventilation.

Ill. 3. Key numbers from Be10 first building analyses

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Ill. 4. Temperature inside the existing apartment throughout the year

Temperature for 24 Hours (existing building) - 1.1.2002

Temperature for 24 hours (existing building) - 15.7.2002

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Ill. 5. Temperature inside the existing apartment during the 1st of January in winter and on 15th of July (calculations done for weather data from year 2002)

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Passive solutions Because so many aspects had issues the apartment and the whole building needed complex solutions. There are three thermal zones created for the BSim calculations: apartment without bathroom, bathroom and stair case.

Walls One of the most crucials problems were the big areas with the large transmission losses, which were caused mainly by poorly insulated walls and windows. After small research on the local Århus Kommune’s strategy on the renovation of old buildings the decision was to not remove the existing layers but to add new one to them. Even though it was easy to get the same, better results with thinner walls, it would cost a lot of money to remove previous layers and only leave the core. The only one exeption would be if after inspection moisture would be found in or between the layers.

For the new insulation it was crucial to use PIR/PUR technology insulation. It is cheap, extremely efficient and the highest đ?ž´=0,022 [W/(mK)]. It goes easly down to đ?ž´=0,018 [W/(m∗K)] but the higher lambda the higher costs are. Decision was to use higher class PIR plates đ?ž´=0,020 [W/(m∗K)] which are still afordable.
 During the renovation there were also used Kingspan’s Optim-r vaccum insulations with đ?ž´=0,007 [W/(m∗K)]. Because of their extreme prices it was used only as a wall insulation between the apartments, in the connection between the balcony window and the exterior wall.

Results of such technological approach are showed in table 1 below.

Building elements

Existing Thickness [m]

Renovated

U-value [W/mÂ˛âˆ—K]

Thickness [m]

U-value [W/mÂ˛âˆ—K]

North wall

0,35

0,56

0,61

0,07

East and west walls

0,24

0,80

0,5

0,07

Roof*

0,43

0,33

0,45

0,06

* The thickness vary because of the slope layers. Given number is the average thickness.

Table 1. Example results of the U-values for the old and new walls.

Windows There were many concerns about the windows and how to improve them beside using just new window systems. Calculations of the existing building have showed that they are the bigest cold bridge in entire building. Beside changing jst the windows the decision was made to also reduce number o the frames to reduce frame area and volume which are the direct main source of the coldbridges. That is why on the kitchen side of the building there is still one small window and one big more instead of two. The same goes for the balcony windows - instead of having two windows and the doors, there is one big fixed glazing and the doors.

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Changing windows and insulating walls better helped a lot with keeping the heat inside the building (fig. 6).

Temperature for 24 Hours (renovated building) - 1.1.2002 21,2

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Ill. 6. Temperature inside the renovated apartment during the 1st of January (calculations done for weather data from year 2002)

Venting and ventilation After calculating the air flow and air needs it was clear that for satisfactory air change rate there will be a need for the mechanical ventilation (each apartment would have independent system). It would be used only during the winter time and supply heating thanks to heat recovery system.

During summer months ventilation is off and venting is taken into consideration. It keeps the apartment chill enough to reduce Ill. 7. Temperature inside the renovated apartment during the high temperatures from outside during the 15th of July (calculations done for weather data from year 2002) summer (fig. 7). Of course ventilation and venting are also helping with too high amounts of COâ‚‚ from the apartment air volume, reducing the polution (fig. 8).

Temperature for 24 Hours (renovated building) - 15.7.2002

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Ill. 8. Example polution on 1st of January in winter - before (left) and after renovation (left)
 (calculations done for weather data from year 2002)

For better air flow there was decision to remove the wall between living room and kitchen. It allowed to have cross ventilation through the apartment (fig. 11 appendix 2). It also helped a bit with the daylight factor in the middle of the apartment.

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Daylight factor As mentioned before, there were changes made in the window systems. Of course it made thermal problems smaller but it also made the rooms a bit brighter because of the reduction of the mullions and because that there were no longer two smaller windows but one big instead. Of course as mentioned before, removing the wall between the kitchen and living room also improved the daylight factor (fig. 12 appendix 3). Simulation were done in Velux Daylight Visualizer 2.

Active solutions To achieve a zero energy building which meets requiremts of energy frames for building class 2020 the building must not only reduce energy consuption as much as possible but also produce some of it. For example to achieve selfsustainability for domestic appliances. The area of solar cells needed is calculated in appendix.

Results As a final result building started to fulfil the 2020 regulations, decreasing Total Energy Requirement (TRE) to just 16,8 kWh/m² per year.

This includes production of the energy from the solar cells (fig. 9).


Ill. 9. Key numbers from Be10 after renovation

Existing Building

Domestic hot water 8%

Pipe loss 1%

Mechanical ventilation 8%

Equipment 14%

Heat demant 22% Equipment 49%

Heat demant 77%

Pipe loss 5,52 Heat demant 354 Domestic hot water 35,27 Equipment 65,8

Domestic hot water 21%

Heat demant 29,8 Domestic hot water 28,15 Equipment 65,8 Mechanical ventilation 10,8 Ill. 10. Ratios of different energy demands

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Renovated Building

From author: Big thanks to my Zero Energy Building research group: Ana Habijanec Jakob Soelberg Jesper Søndergaard Totto Rátkai

References Literature Brabrand boligforening, 2016, Skovgårdsparken, accessed 15 February 2016 < http://bbbo.dk/afdelinger/skovgardsparken > Aalborg Universitet, 2016, Assignment description spring 2016 from Zero Energy Building course, Aalborg Universitet Wikipedia, 2015, „Skovgårdsparken”, accessed 15 February 2016 < https://da.wikipedia.org/wiki/Skovg%C3%A5rdsparken >

Illustations All illustrations and pictures are my own.

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Appendix

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Appendix 1 - U-values calculations and wall details To calculate the u-values of the buildings elements the equation under is used. This equation requires the thermal conductivity and thickness of the materials there are used:

Rse: external transition value 0,04 m2K/W Rsi: internal transition value 0,13 m2K/W đ?&#x17E;´: heat transfer coefficient l: materiale thickness

Reinforced concrete: đ?&#x17E;´= 2,11 W/mC, l = 0,16 m Mineral wool: đ?&#x17E;´ = 0,051 W/mC, l = 0,1m Concrete: đ?&#x17E;´= 1,74 W/mC, l = 0,1m PIR insulation: đ?&#x17E;´ = 0,02 W/mC, l = 0,24m Plaster: đ?&#x17E;´ = 0,2 W/mC, l = 0,02m

Reinforced concrete: đ?&#x17E;´= 2,11 W/mC, l = 0,06 m Mineral wool: đ?&#x17E;´ = 0,051 W/mC, l = 0,061m Concrete: đ?&#x17E;´= 1,74 W/mC, l = 0,04m PIR insulation: đ?&#x17E;´ = 0,02 W/mC, l = 0,24m Plaster: đ?&#x17E;´ = 0,2 W/mC, l = 0,02m

Reinforced concrete: đ?&#x17E;´= 2,11 W/mC, l = 0,12 m PIR insulation: đ?&#x17E;´ = 0,02 W/mC, l = 0,3m Waterproof insulation Conrete đ?&#x17E;´= 0,7 W/mC, l = 0,05m Asphalt đ?&#x17E;´= 0,44 W/mC, l = 0,03m

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Appendix 2 - Ventilation

Ill. 11. Airflow through cross ventilation

Appendix 3 - Daylight factor

Ill. 12. Daylight factor analysis

Appendix 4 - Reflection Software proved to be very handy it also turned out to be completely not intuitive and not user friendly. Even though it is very powerfull, it is also very frustrating because at this stage of its development it takes too much time to create needed elements in those programs. What is more IFC standard is not well supported. However there is still a lot w place for the improvements and futher developments.

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Appendix 5 - Comparing results Energy Gains / Losses (existing building) - kWh / apartment 10000

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Energy Gains / Losses (renovated building) - kWh / apartment 10000

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Ill. 13. Comparing energy loses between old and renovated building Temperature for 12 Months (renovated building) - 2002 25

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Ill. 14. Temperatures for renovated building

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Appendix 6 - Air change rate The pollution load is calculated. It is assumed that the average person load of each apartment is 3 persons.

The experienced air quality is read off to 1.4 dp. The outdoor air quality is 0.05 dp. We insert in the formula:

The air change is then.

Appendix 7 - Renovation drawings

Ill. 15. Aerial view of the renovated building

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Ill. 16. Section through the the renovated building

Ill. 17. Basement plan

Ill. 18. Ground level plan

Ill. 19. +4 Floor plan

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Ill. 20. Elevations after renovation; west eleation on top, east elevation on bottom

Ill. 21. Elevations after renovation; north eleation

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