Impact of Thermal Mass on Energy and Comfort - A parametric study in a temperate and a tropical climate

Abstract

ABSTRACT The use of thermal mass in a building can result in an improved thermal comfort and energy savings. On the other hand, thermal mass can also be detrimental when it is not properly used. The outdoor climate is an important factor that influences the performance of thermal mass and will determine if a heavy weight or a light weight construction is desirable. A shoebox model of one zone resembling a typical social house in Mexico is simulated in a temperate climate like Mexico city and a tropical climate corresponding to the city of Veracruz. It was analyzed how different parameters such as the type of glass, exterior shading, ground insulation, window size and natural ventilation affect the performance of thermal mass. Free running temperature simulations in typical seasonal days are conducted in order to describe comfort by means of the operative temperature. Annual year simulations are performed to estimate the energy demand. The most relevant simulation cases from the shoebox model are implemented in the real house. The results show that thermal mass is beneficial in a temperate climate such as in Mexico city. Comparing with a light weight construction, thermal mass in a heavy weight building can compensate for the increase in temperature variations and energy demand due to a larger window area, or to a poor U-value of the windows. In a tropical climate like Veracruz, a light weight construction with low thermal mass is preferable. Thermal mass is beneficial as soon as the free running temperature response of the building is within the comfort limits, otherwise it can be a liability and result in a larger energy demand.