Potential energy cost savings by use of building roofs as thermal storage of a multi-storied building

摘要

The thermal mass of a building has been used for more than two decades to shift the peak cooling load occurring during the day time to evening or night time. This is typically accomplished by use of concrete slabs embedded with pipes carrying hot or chilled water to meet the heating or cooling load, respectively. The water temperature drops across the coils and the frequency and intensity of room air circulation can be varied, along with controlling the gains through the windows, to shift the peak load hours to the nighttime when energy costs are cheaper and electric demands are lower. This thesis deals with the transient finite element heat transfer analysis of a concrete slab embedded with pipes circulating heated or chilled water of a multi-storied office building. A hypothetical office building in Chattanooga, Tennessee, USA is analyzed with weather data of that locale. The electrical power consumption of such a system operating at milder conditions of evening or night hours is estimated by use of hourly weather data. The estimated electric power consumption is then compared to the traditional method of operations. The influence of the wall envelope, including the size and orientation of windows, is considered in reducing the energy gain or loss from the space. The results presented in this thesis identify the potential energy cost savings resulting from use of such a system as well as challenges involved compared to traditional buildings in commercial applications.