Comparison of space cooling/heating load under non-uniform indoor environment with convective heat gain/loss from envelope

Abstract

The indoor parameters are generally non-uniform distributed. Consequently, it is important to study the space cooling/heating load oriented to local requirements. Though the influence of indoor set point, heat sources, and ambient temperature of convective thermal boundary on cooling/heating load has been investigated in the uniform environment in previous research, the influence of these factors, particularly the convective heat gain/loss through a building envelope, on cooling/heating load of non-uniform environment has not yet been investigated. Therefore, based on the explicit expression of indoor temperature under the convective boundary condition, the expression of space cooling/heating load with convective heat transfer from the building envelope is derived and compared through case studies. The results can be summarized as follows. (1) The convective heat transferred through the building envelope is significantly related to the airflow patterns: the heating load in the case with ceiling supply air, where the supply air has a smaller contribution to the local zone, is 24% higher than that in the case with bottom supply air. (2) The degree of influence from each thermal boundary to the local zone of space cooling cases is close to that of a uniform environment, while the influence of each factor, particularly that of supply air, is non-uniformly distributed in space heating. (3) It is possible to enhance the influence of supply air and heat source with a reasonable airflow pattern to reduce the space heating load. In general, the findings of this study can be used to guide the energy savings of rooms with non-uniform environments for space cooling/heating.