66 Theoretical Analysis on the Building Internal Thermal Mass in Passive Solar House Based on a Simplified Thermal Model Available to Purchase

The thermal performances of building envelopes have been investigated in various theoretical and experimental studies. For the building internal thermal mass, researchers usually obtain the thermal properties of building internal mass to develop proper models for calculation and investigation. However, what kind of internal thermal mass performance is helpful for us to obtain comfortable indoor environment has not been well understood yet.

In this paper, a simplified two-opening one-zone model is presented to optimize the building internal thermal mass in passive solar house, in the given indoor and the outdoor environment conditions. The results show that the indoor air temperature fluctuation decreases with decreasing ΔT_s∕ΔT_out, and decreases as the time constant τ increases; the dimensionless convective heat transfer number λ determines the minimum of dimensionless indoor air temperature fluctuation which tends to be 1∕(1+») when the time constant τ approaches to infinity. The phase shift of indoor air temperature increases with increasing τ and ΔT_s∕ΔT_out.