Experimental investigation on the heat transfer performance of ventilated floor with the influence of solar radiation

Abstract

A heating system combing the solar air collector with the ventilated concrete floor (SAC-VCF) is proposed for application in residential buildings on Western Sichuan Plateau. For the integrated system, the solar energy is firstly absorbed by the solar air collector and stored inside the floor, then it is released at night to supply heat to the room. However, the intensive solar irradiation during the daytime, can cause the local overheating of floor surface and affect the heating performance of the VCF. In this paper, a test chamber is constructed to study the heating performance of the ventilated concrete floor with the effect of local solar radiation. Twenty-three cases with different ventilation rates and supply air temperatures have been performed with and without the solar radiation under steady-state conditions. With the effect of solar irradiation, the average surface temperature of floor is significantly affected with a maximum increase of 4.9 ℃. The local solar radiation weakens the heating supply of the ventilated air in the irradiated area, when increasing the solar radiation to 440 W/m2 the total heat transmitted to the floor through the ventilated air can be reduced by 46%. However, the total heating capacity of the VCF increases from 60.8 W/m2 to 99.0 W/m2, which is increased by 63%. Therefore, with the effect of the solar irradiation, the heating supply of the ventilated air is reduced while the total heating capacity of the VCF is increased, the solar radiation is one of heat sources of the VCF. Thus, the reasonable use of solar radiation can enhance the heat transfer performance of the VCF.