Analysis of a Low Energy Building with District Heating and Higher Energy Use than Expected

by Foruria Ander Arrese

Institution: Högskolan i Gävle
Year: 2016
Keywords: Energy; Ventilation; District Heating; residential Buildings; Envelope; Engineering and Technology; Environmental Engineering; Energy Systems; Teknik och teknologier; Naturresursteknik; Energisystem; Energisystem – magisterprogram (sv eller eng); Energy systems – master’s programme (one year) (swe or eng); Energy systems; Energisystem
Posted: 02/05/2017
Record ID: 2075728
Full text PDF: http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-21738


In this thesis project, a building in Vegagatan 12, Gävle has been analysed. The main objective has been to find why it consumes more energy than it was expected and to solve theoretically the problems.This building is a low energy building certified by Miljöbyggnad which should use less than 55kWh/m2 year and nowadays it is using 62.23 kWh/m2. In order to find why the building is using more energy than the expected several different things has been measured and analyzed.First of all, the heat exchanger of the ventilation unit has been theoretically examined to see if it works as it should and it does. This has been done using the definition of the heat exchangers.Secondly, the heating system has been analysed by measuring the internal temperature of the building and high temperatures have been found (around 22°C) in the apartments and in the corridors. This leads to 5-10% more use of energy per degree.Thirdly, the position and the necessity of all the heaters have been checked. One of the heaters may not make sense, at least in the way the building has been constructed. This leads to bigger heating needs than the expected.Fourthly, the taps and shower heads have been checked to see if they were efficient. Efficient taps and shower heads, reduce the hot water use up to 40%. The result of this analysis has been that all taps and shower heads are efficient.Fifthly, the hot water system has been studied and some heat losses have been found because the lack of insulation of several pipes. Because of this fact 8.37kWh/m2 are lost per year. This analysis has been carried out with the help of an infra red camera and a TA SCOPE.Sixthly, the theoretical and real U values of the different walls have been obtained and compared (concrete and brick walls). As a conclusion, the concrete wall has been well constructed but, the brick wall has not been well constructed. Because of this fact 1 kWh/m2 of heat are lost every year. Apart from that, windows and thermal bridges have also been checked.