Space Heat Power Demand for Existing Buildings : Feasibility, Improvement-Measures, and Impact on Climate Performance Using a Swedish Multi-Dwelling Building as Case Study

Abstract: The most commonly used indicators of energy performance of existing buildings in Sweden, Specific Energy Use (SEU) and Primary Energy Use (PEU), are very rough measures that does not account for short term effects and therefore they are not necessarily well suited to evaluate climate performance of existing buildings. In this thesis the similar but slightly different indicators Miljöbyggnad Heat Power Demand (MHPD) (Värmeeffektbehov in Swedish) and Feby Heat Loss Number (FHLN) (Värmeförlusttal in Swedish), both indicators of Space Heat Power Demand (SHPD), has been evaluated as complementary indicators to SEU and PEU. SHPD focus on energy lost through transmission, infiltration, and ventilation and it is evaluated at Dimensioning Winter Outdoor Temperature (DWOT). The thesis has been done in cooperation with the consultancy company WSP and the housing company Rikshem. Rikshem has provided building construction data and energy data for a multi-dwelling building located in Norrköping, Sweden. The data has been used to find SHPD through (1) linear regression of the building energy signature, (2) simplified manual calculations, and (3) simulations in the dynamic energy calculation software IDA ICE. Results from the different methods and the use of the methods themselves have then been analyzed and compared. In a subsequent step different energy measures that affect SHPD has been simulated and the impact on both SHPD, SEU, and PEU has been evaluated to see both short term impact and impact on yearly energy use. For the studied building the SHPD-value for linear regression of energy signature was lowest (33.3 W/m2,Atemp), followed by the value for dynamic energy simulation (36.7 W/m2,Atemp). Highest was the value for simplified manual calculation (38.8 W/m2,Atemp). The relatively small difference indicate that it could be feasible to map a building stock using different methods. However, this study has been limited to examining one non-complex building and it is likely that many difficulties will arise if a larger set of buildings with different complexities and conditions would be analyzed. If worked with, these difficulties can likely be overcome through gaining more knowledge of the construction of buildings and measuring of hourly energy use for each building. Focus on SHPD of buildings would mainly favor improvement of buildings’ climate shells, and such measures are, in general, good for mitigation of negative climate impact of buildings. Depending on if the Miljöbyggnad- or the Feby- definition of SHPD is used, different ventilation heat recovery measures can be favored. Climate impact of the different ventilation heat recovery measures can be both negative and positive depending on composure of the energy system around the building and depending on boundaries of analysis.