Abstract

The doctoral thesis presents the results of numerical investigations on the influence of walls’ thermal capacitance on indoor thermal comfort. A proper set of thermal parameters of a building structure can considerably limit the heating / cooling demand, and passively increase the indoor thermal comfort. However the effect of building thermal capacitance on indoor conditions is complex and not always beneficial. Among a great number of interfering factors are e.g. climatic conditions, building shape, ventilation system type, operational schedule and many others. The aim of the present study is to investigate the potential of high thermal capacitance walls under the climatic conditions typical for Poland. The investigations are based on a number of simulations performed using a numerical model of a part of buildings. The model consists of two main separate components: the indoor air submodel and the external wall submodel. The submodels work together in a co-simulation, exchanging the solution at the common boundaries. A considerable part of the model has been developed by the author. The model treats indoor space as a nonuniform environment, and provides the basic indoor environment parameters affecting the human thermal comfort, i.e. the air temperature and velocity. The output parameters are analyzed separately but they are also used to calculate the expected thermal sensation in the considered space. The evaluation of the walls’ thermal capacitance potential to increase the level of the indoor thermal comfort is based on the results produced by a significant number of various simulations. The analysis covers different wall structures, two different ventilation air exchange rates and two types of the outdoor temperature profiles: (1) one-week sol-air temperature profile and (2) simple step change temperature profile. The results indicate that indoor thermal comfort can be increased by a proper thermal capacitance of building walls. However, it is also shown that the ventilation air exchange rate can have a prevailing influence on indoor conditions, limiting stabilizing effects of the walls’ thermal capacitance.

Author (1)