An Energy Audit of Kindergarten Building in Vallbacksgården

Sammanfattning: Energy consumption rises continuously every year. Globally, buildings count for half of electricity consumption and 20%-40% of total energy consumption. Building energy sector consumed 40% of total energy use in Sweden. The vital of reduce energy consumption is to enhance building efficiency. This energy audit work investigates how energy consumes of kindergarten building in Vallbacksgården. Then give out cost effective suggestions to improve energy efficiency for object building. The result shows total amount of energy input of the building is equal to 241.9 MWh. While district heating takes the largest part of energy input that correspond to 188.9 MWh (78%), and cost around 123500 Kr annually. Furthermore, energy 38.0 MWh (16%) is contributed by solar radiation, which becomes second largest source of energy input. Finally, internal heat generation is the smallest contributor of energy input which counts 15.0 MWh (6%). For energy output, majority of heat loss is leaded by transmission losses. It cost 190.4 MWh per year that shares 79% of total energy output. Nature ventilation losses of object building shares 17% of total heat output which is 41.7 MWh. Mechanical ventilation and hot tap water have energy consumption with 7.8 MWh and 2.0 MWh respectively. They take rest 4% of total energy output. According to the finding, several reasonable suggestions will be given. Firstly, for the costless solution, decreasing indoor temperature 1℃ or 2 ℃ is able to reduce heating demand 9.0 MWh or 18.1 MWh annually. It will reduce CO2 emission 131859g- 266070 g, and save 5274 – 10642 SEK per year. Secondly, substitute district heating systems by ground source heat pump is an environmental solution. Using ground source heat pump has priority of environment, which lower CO2 emission 1909200 g/year and save 68262 SEK/year by analyze. Investment for this solution is 979000 SEK and the payback time takes 14.3 year. Replace old windows is a moderate solution of cost. Substitution by using energy glass can reduce 20.9 MWh heating demand and 307377 g CO2 every year. New energy glass windows can cut 13591 SEK for district heating every year. The renovate investment and payback time are more than 159732 SEK and 11.8 year respectively.