Do New and Renovated Schools and Kindergartens Secure Sufficiently High Indoor Environmental Quality?

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1 Do New and Renovated Schools and Kindergartens Secure Sufficiently High Indoor Environmental Quality? Pawel Wargocki Technical University of Denmark

2 Project main objectives Dissemination of solutions for quick and robust energy retrofits of educational buildings Promotion of retrofitting facades containing wooden elements, either prefab or not Promotion of solutions creating decent conditions promoting learning and proper development of children (no risks for health)

3 19 educational buildings (frontrunners) 12 schools + 7 kindergartens 13 new constructions + 6 renovated

4 Definition of a frontrunner Timber facades 66% reduction in energy use (primary energy) compared with typical energy use for the similar (conventional) buildings 20% of energy demand covered by renewables IEQ high level with special technological solutions

5 Display of frontrunners General information, i.e. location, type of the project, cost, main contractor, architectural company, building owner, gross floor area, number of floors and construction time. Cooperation model, i.e. organizational and financial instruments leading to high performance renovations. Description of construction, i.e. information on prefabricated timber facades. Energy data, i.e. information on primary energy consumption, energy savings, energy sources and use of renewable energy. Technical solutions for achieving ventilation and high indoor environmental quality especially as regards the type of illumination and information on day-lighting. Other relevant data.

6 Energy, summary Sources: district heating, biomass (pellets, chips), natural gas, renewables Renewables: PV, geothermal, wind power Coverage of renewables in total energy use: 8-100% Energy use (heating and total): 6-42 kwh/m2floor U-values, walls and windows: and 0.8 (triple glazing) W/m2K Airtightness: h-1 (insufficient data)

7 Ventilation, summary Balanced mechanical ventilation, mostly, w/ and w/o CO 2 control Decentralized ventilation system, less frequent Hybrid ventilation system, sporadically All with heat (energy) recovery (heat and moisture), ERVs: 80-90% Other solutions: free cooling, night ventilation (cooling), low-emitting materials, floor heating, adiabatic humidification, façade-integrated ducts, electric heating, roof windows (skylights) LED, automated blinds/shading, detection switches

8 Aim: Technical signpost

9 Objective To investigate winning concepts and technologies as regards indoor environmental quality

10 Measurements (crude mapping of IEQ) Physical measurements and subjective ratings of pupils and teachers in 10 frontrunners and 5 conventional counterparts One class/playroom per school (3rd-5th grade)/kindergarten 2 months between January and April 2015 (heating season)

11 Frontrunner buildings 5 randomly selected conventional buildings

12 Physical measurements (continuous) Carbon dioxide Air temperature; Relative humidity Light intensity; Logging Sent by post and deployed by janitors or project staff

13 Results: CO 2 CO 2 <2,000 ppm; ppm (on avg.), lower in frontrunners ~3-4 L/sp

14 Best CO 2 performing frontrunners Kindergarten (new construction) Central balanced mechanical ventilation system, heat recovery 85%; 13.3 kwh/m 2 Kindergarten (new construction) Central balanced mechanical ventilation, heat recovery 90%; 24 kwh/m 2 School (new construction) Decentralized ventilation system w/co 2 control, heat recovery N/A; 41 kwh/m 2 (total) School and kindergarten (renovation) Central balanced ventilation system w/co 2 control, heat recovery 80%; 8 kwh/m 2

15 Less-well CO 2 performing frontrunners School (new construction) Central balanced mechanical ventilation system w/co 2 control, heat recovery 84%; 13 kwh/m 2 School (renovation) Decentralized ventilation system w/co 2 control, heat recovery 80-90%; 15 kwh/m 2 School (renovation) Central balanced mechanical ventilation system w/co 2 control, heat recovery 84%; 12 kwh/m 2

16 Results: Temperature Temperature: o C; Variations: ±0.5-1K Estimated PMV=neutral-to-slightly warm, PPD~15% (1 clo, 1.2 met)

17 Conclusions It is not possible to associate any particular technical solution applied in frontrunner buildings with the actual indoor environmental conditions Measured CO 2 concentrations in frontrunner buildings are on average lower than 1,300 ppm Temperature fluctuations in frontrunner buildings are low and the average temperatures are from 22 to 25 o C (slightly on a higher side) Good news and bad news: Energy retrofits of educational buildings and new energy efficient buildings do not worsen indoor environmental quality in classrooms and playrooms and they do not significantly improve indoor environmental quality either

18 Limitations Non-representative selection of frontrunner buildings i.e. buildings that have undergone retrofits New constructions, not only retrofits Measurements in the subset of frontrunners, one classroom or playroom, one-season No registration of average number of students in the class Minor or no difference in technical systems installed in frontrunner buildings Lack of advanced systems for achieving high indoor environmental quality

19 Technical signpost Balanced (central or decentral) mechanical ventilation with energy recovery and CO 2 control???

20 Acknowledgments Present work was supported through grant IEE/131786/SI awarded by the European Commission through Intelligent Energy Europe Programme for the project titled Sustainable school building renovation promoting timber prefabrication, indoor environment quality and active use of renewables (RENEW SCHOOL). 9 countries and 13 partner organizations; Focus on central-east and north European countries with tradition in wood industry and timber craftsman companies / SME

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