Indoor Thermal Climate Criteria and the Effects on the Overall Environmental Performance of Air-Conditioning Systems

The cooling loads of an office building vary with the desired indoor thermal climate. However, there is a lack of knowledge on how significantly the various indoor climate criteria affect the overallenvironmental performance of the air-conditioning systems. Here, we analyze the environmentalconsequences of the energy use, as well as the possible modifications of the system design andcorresponding use of materials. The analysis is based on a theoretical case study of an airconditioning system designed for a typical office building situated in Sweden. The environmentalperformance is evaluated by a life cycle assessment (LCA) method, taking into account theproduction, the user, and the disposal stages of the life cycle. For the same building, several scenarios of the user stage corresponding with the different requirements on the indoor thermal climate in the building are studied. We conclude that requirements on the indoor climate should be established at appropriate levels, taking into account the environmental performance of the air-conditioning system.