Energy Efficient and Air tight Residential Buildings in Cold Climate Research at Umeå University

Transcription

1 Energy Efficient and Air tight Residential Buildings in Cold Climate Research at Umeå University Thomas Olofsson Professor in Energy Efficiency Energy Efficiency - with a focus on buildings Dept. of Applied Physics and Electronics, Umeå University Research profile Investigations of building energy performance and energy use Data models based on monitored and physical simulations Focus on building energy end use Research questions Evaluations of energy use Estimations of performance parameters Analysis of LCC/LCP How to obtain support the design process How to improve the knowhow, learning processes Applied research Contributions that can be useful for improved knowledge and development as well as introduction of new technology Expected use in relative short time horizon Often in cooperation with specific stake holders 2 1

2 Brief overview of four research projects 1. Evaluation of energy efficient of a number of small residential buildings 2. Evaluation of energy efficiency measures in multifamily buildings - Sustainable Ålidhem 3. Investigations of strategies for building energy efficiency and air tightness - IEEB 4. LCP-model, A Net Profit Analysis 3 1. Evaluation of energy efficient residential buildings A cooperation project - Umeå University & Umeå Municipality 4 2

3 Energy performance for the investigated buildings Object A Temp Q SpaceH Q DHW Q Hel Totalt B q 50 exch U m U m-proj m 2 kwh/m 2 yr kwh/yr kwh/m 2 yr kwh/yr kwh/m 2 yr kwh/yr kwh/m 2 yr kwh/yr W/ C l/sm 2 exch/h W/m 2 C W/m 2 C # F , , , , ,15-0,18 0,20 0,15-0,18 0,14 # P , , , , ,34 0,37 0,21-0,24 Ej proj. # C , , , , ,37-0,37 0,52 0,16-0,18 0,25 # D , , , , ,25 0,44 0,21-0,24 0,21 Gröngård , , , , ,05-0,08 0,56 0,25-0,28 0,21 Kullen , , , , ,64-0,63 0,46 0,32-0,33 0,28 5 Specific energy use Object Measured Swedish building code - BBR FEBY12 VFT Max 19 W/m 2 Classification kwh/m 2 yr kwh/m 2 yr kwh/m 2 yr W/m 2 # F Passive house # P Better than BBR # C Better than BBR # D Low energy house Gröngård Near minienergi house Kullen Low energy house Used energy for space heating :# C = 37 kwh/m 2 yr heat pump. # F = 35 kwh/m 2 år wood pellets stove (estimated) VFT = B*(21 (-24,5))/Atemp Minienergi house: VFT max 22 W/m 2 och Specific energy use max 78 kwh/m 2 yr 6 3

4 Conclusions of the investigation No risk for mold problems in the positions where moister and temperature measurements were conducted There is a potential for further increased energy performance by simple corrections in HVAC-system. A design with open space and larger room high gives possibilities for deceased air exchange Ground based pre-heating of supplied air proved to decrease the use of energy Measured air leakages in the houses proved to influence the measured specific energy use for space heating The defined energy demands according to the Swedish building code BBR was easy to achieve Monitor continuously and a lot Publication (in Swedish): Energieffektivt byggande i kallt klimat, Slutrapport, , Ronny Östin, Erik Eklund Sustainable Ålidhem evaluation of energy efficiency measures in multifamily buildings An investigation in cooperation with Umeå municipality AB Bostaden Umeå Energi Reference building Pilot building Background 540 apartments (137 new, 403 refurbished) Existing buildings, Goal to improve energy efficiency with 50 % The investigation is based on two comparable buildings 8 4

5 Obtained energy efficiency The obtained energy efficiency is often requested without a clear definitions in mind. Depending on the perspective 3 different analyses were conducted: 1. The energy efficiency of the building itself and the technical systems, i.e. the influences of the inhabitants is not included. 2. The total energy use of the building. The total change in supplied energy is evaluated, thus conditions of the building and the influence of the inhabitants is included. 3. The Swedish building code (BBR) parameter. It is a combination of (1) och (2), but all supplied energy is not included. 9 Summary of evaluation for the pilot and reference house according to the 3 introduced perspectives Building & technical systems Building total energy use BBR-parameter Reference Pilot Reference Pilot Reference Pilot Radiatorer Ventilation DHWc-loss DHW Household elec Process elec Solar - elec Total Energy efficiency 44.4% 44.4% 42.1% 10 5

6 3. Investigations of strategies for building energy efficiency and air tightness in Finland, Sweden and Norway IEEB 1. Mapping of building code regulations and passive house specifications 2. Mapping of the methods used to verify energy performance requirements in the building code, passive house specifications or energy certifications 3. Mapping of existing methods to analyze air tightness, both to verify and to improve air tightness. 4. Simulations of single-family building in IDA- ICE, to compare national building codes 5. Qualitative (Delphi) study to evaluate methods to analyze air tightness 11 National regulations buildings codes Sweden Norway Finland Finland Requirement U-values [W/m 2 K] x x Space heating energy [kwh/m 2 ] x x Net energy use/demand [kwh/m 2 ] x Delivered energy [kwh/m 2 ] x x Air tightness [h -1 ] x x Proportion of renewable fuels x Area Heated floor area, external x Heated floor area, internal x x x Climate zones None x x Three x Four x Included sources in the net energy Heating x x x Hot water x x x Ventilation and auxiliary energy x x x Cooling x x x Lighting x x x Household electricity x x Weighting factors used None x x x National Primary x 6

7 National specifications and regulation for air tightness Building codes Passive houses Sweden Norway Finland Finland Sweden Norway Finland Finland Level of requirement Measured quantity Alt. 1 Alt Standard x x x x x - x - - Specification x - x x Air permeability, x x VTT RIL Requirement at 50 Pa pressure q 50 Air change rate, n 50 Small buildings a Other buildings - x x x x x x - 2,5 h - 1-1,5 h b h -1 4 h -1 4 m 3 /(hm 2 ) 3 b h -1 4 h -1 4 m 3 /(hm 2 ) 0,3 l/sm 2 0,3 l/sm 2 0,6 h h h -1 0,6 h h h -1 Normalization Volume - x x x x x x Enclosing - x x area c Floor area - Follow up x x x d x d 13 Some Conclusions - Energy Efficiency (IEEB) 1. There exist large variations in what measure is studied when analyzing energy performance 2. Common ways to handle the parameters and uniform measure is required to make comparisons of energy performance possible between countries 3. A common trend towards a more system-focused evaluation of energy performance in the building codes is visible 4. The methods to analyze the energy performance are more similar than the concepts of energy performance itself 5. The review of the energy analysis methods and air tightness, for the building codes in the Nordic countries supports the possibility to use the common ISO standards 14 7

8 Some conclusions - Air tightness (IEEB) In the building production process Improve: Ocular and hand inspection, combined with air velocity measurements Verify: Surface temperature measurements New building (before moving in) Improve: Surface temperature measurements (Acoustic/Trancient = experimental alternatives) Verify: Standard EN Existing building, inhabited Improve (for refurbishments): Surface temperature (Acoustic/Trancient= experimental alternatives) Verify: Ventilation system/tracer decay (ventilation rate) LCP-model - A Net Profit Analysis Identification of most economically efficient energy saving technology based on Building system perspective The property owners financial situation Cash-flow analysis Net profit Studies early in the design process The computation combines three main functions Calculation of investment costs Calculation of energy use Calculation of net profit (the investment appraisal) 16 8

9 Default Triple glazed Windows Duble glazed Windows 35% window area 65% window area Concrete frame Roof: thin insulation Roof: thick insulation SFP 2 SFP 3 Heat exchanger 50% Heat exchanger 80% Air flow: 3 l/s m2 Air flow: 5 l/s m2 Calculation of net profit net profit property value 2 net rental income time capital investment 1 3 NP n 1 NI PV n 10years 10 n 1 IR 1 IR IC 17 Parameter Study of Net Profit net profit [ksek]

10 Results of the LCP-analysis Not as accurate energy use and costs as from a detailed calculation Good support for decisions in the early stages Reduced time and cost of doing the investigations A better understanding and communication A transfer of competence 19 A perspective for building energy efficiency The total energy use of heated floor area has to decease with 20% to % to 2050, based on the energy use in 1995 Before 2020 the dependency of fossil fuels must decrease and the use of renewable energy must increase continuously In order to research the energy goals the existing stock of building has to be extensively refurbished In Sweden that the building renovation industry is estimated to spend billion SEK until

11 Thanks! 21 11