Investigation of the use of solar thermal buffer zone in buildings

Abstract

This paper presents results of a collaborative study that is being carried out by the Thermal Processing Laboratory (TPL), the Department of Civil Engineering and Public Works and Government Services Canada (PWGSC). The main objective of this study is to investigate the feasibility of passive means to achieve net-zero energy (NZE) in federal buildings in Canada. An experimental and numerical investigation of the fluid flow and heat transfer inside a solar thermal buffer zone (TBZ) has been carried out. The numerical work has been conducted using the ANSYS-CFX commercial software package. A TBZ is an air-filled cavity that envelopes the building. It acts as an additional insulation and allows solar energy collected from the south side of the building to be distributed throughout the other sides, hence, reducing the heating load of the building. The main objective of the current study was to determine the optimum TBZ size. Considering a one-third model of a typical floor in a building located in Ottawa, Ontario, Canada, our results obtained using an average winter day solar intensity show that the TBZ could result in a significant saving in the building heating load, which makes the TBZ an attractive passive technology to achieve significant sustainable energy savings in commercial buildings.