Inglasning av tegelfasad - Energianalys samt fallstudie på ett flerbostadshus och på Byggnad 22
Sammanfattning: One of Sweden's political objective is to increase energy efficiency. One way to achieve the objective is by making demands on the use of energy after a building has been renovated. Regarding the building's cultural and architectural values there are cases where it is not possible to apply proven methods to meet the demands, and other alternative methods must be sought. Such an alternative method is the double skin façade. The method is applied to a small brick building in the city of Malmö and implies that an external glass façade is added to an already existing façade. The purpose of the double skin façade is to reduce transmission losses through the walls and to get the double skin façade to act as a passive pre-heater of the supply air. The air space in the double skin façade is also meant to be used as a solar air heater to increase the heat storage in the building frame. Previous studies of the brick building in Malmö has been based on measured data from limited periods. Even though the results varied in size, all the studies confirmed that energy saving occurs regarding the heating of the building. One of the purposes with this thesis has been to compile and evaluate a longer period of measured data from the building. The result of the evaluation supported that energy saving is made regarding to the heating of the building. The transmission losses decreased by 24,1 % and ventilation losses decreased by 26,1 %. Thermal and energy efficiency of the double skin façade were calculated to an average of 0.315 and 0.53 and an effective U-value were calculated on the average to 0.55 W / K, m². A linear relationship was found where a lower outside temperature gave a higher positive difference to the temperature in the double skin façade, during heating periods. Another purpose of this thesis has been to examine the potential energy saving, regarding to the heating of a building, when an external glass façade is added to an existing brick façade on an apartment building in Sweden. In addition, the thesis was also meant to simultaneously examine how the thermal comfort is affected when a glass façade is added. No measured data from a real apartment building with a glass façade were found so seventeen models were made in the simulation program IDA ICE 4.7. Four of the models were full-scale apartment buildings and the other thirteen models were geometrical adjusted. All models have been provided with different conditions regarding to ventilation systems, glazing of the balconies, and glazing of the south façade. The adjusted models were also simulated in three different geographical places in Sweden. The result of simulations confirmed previously results, which was that an energy saving is made regarding to the heating of the building. Highest energy saving when the south façade was glazed were 25 % for the full-scale apartment building, and 37 % for the adjusted model. In addition, differences were found on how the different conditions affected the energy savings. A single FTX system installed in the building made a greater energy saving than a single glass façade, and a method with pre-heated supply air through the double-skin façade only gave a marginal increase in energy saving as the heat exchanger efficiency was not fully utilized. No percental differences in energy saving was found when models with different geographical places were compared, however did the energy saving in kilowatt hours increase in the northern parts of the country due to higher initial energy use. The thermal comfort was mainly affected in the upper parts of the apartment building facing the double skin façade. The affect mainly resulted in disadvantages by increased temperatures during summer periods. In a previous study, it was found that it is possible to reach down to a cooler climate behind the brick facade after an external glass facade was mounted and hence, further cooling measures in a double skin façade should be studied.
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