Exergy analysis of building thermal load and related energy flows in buildings

Abstract

In this study, the exergy analysis method was extended to analyse the building thermal load and related energy flows, aiming to investigate the exergy loss as well as improvement potential for building design and analysis. Five office buildings in five major climate zones in China were taken as case studies for the analysis. The building thermal loads and related energy flows were calculated and analysed using the exergy analysis method. Results show that the building exergy load is relatively low compared to the building thermal energy load. However, it is always met by consuming energy of high exergy value (e.g. electricity), indicating the exergy mismatch between the energy demand and supply. The latent exergy load cannot be disregarded for building thermal load and energy flows analysis, especially for buildings in humid climate. Large exergy loss, which is dominated by solar gain, was found in all five reference buildings across different climate zones. This study provides a comprehensive understanding of building thermal load and related energy flows, and would benefit building evaluation and thermal design of building envelop.