Computational Study on Thermal Properties of HVAC System with Building Structure Thermal Storage

Abstract

Building structure thermal storage (BSTS) HVAC systems can store heat during nighttime thermal storage operation (nighttime operation hours) by using off-peak electricity and release it in the daytime air-conditioning operation (daytime operation hours) by utilizing a large amount of the thermal capacity of building structures such as beams, columns and floors composed of concrete. These BSTS systems have recently been considered as one method for leveling hourly electricity demands for HVAC on a day-to-day basis. Through a simulation using a model developed with experimental data, this paper describes how various factors for the design and operation of a BSTS quantitatively affect the charge/discharge performances of a HVAC system. As a result, the following was revealed: the thermal performance of the system is strongly influenced by the daily heat storage operation hours, supply air volume and supply air temperature during the nighttime operation hours, stored heat caused the total daytime cooling extraction to decrease by 11% to 58% and the daily total cooling extraction through nighttime to daytime to increase by 4% to 17% compared with the values of non- thermal storage HVAC system.