Energy and Indoor Environment in New Buildings with Low-Temperature Heating System

Sammanfattning: The aim of this thesis was to evaluate new buildings with low-temperature heating systems in terms of energy consumption and thermal comfort, and to pay some attention to energy savings and indoor air quality. To reach this aim, on-site measurements as well as building energy simulations using IDA Indoor Climate and Energy (ICE) 4 were performed. Results show that the investigated buildings with low-temperature heating system could meet the energy requirements of Swedish regulations in BBR (Boverkets byggregler), as well as provide a good level of thermal comfort. Implementing variable air volume ventilation instead of constant flow, i.e. decreasing the ventilation air from 0.35 to 0.10 l·s-1·m-2 during the whole unoccupancy (10 hours), gave up to 23 % energy savings for heating the ventilation air. However, the indoor air quality was not acceptable because VOC (volatile organic compound) concentration was slightly above the acceptable range for one hour after occupants arrive home. So, in order to create acceptable indoor air quality a return back to the normal ventilation requirements was suggested to take place two hours before the home was occupied. This gave 20 % savings for ventilation heating. The results of this study are in line with the European Union 20-20-20 goal to increase the efficiency of buildings by 20 % to the year 2020.