Experimental investigation of a solar thermal storage heater assembled with finned heat pipe and collective vacuum tubes

Abstract

A novel solar thermal storage heating equipment that is integrated with several highly efficient solar collecting heat storage units (HSU) that filled with phase-change material (PCM) and combined with finned heat pipe to enhance the heat dissipation process was developed and experimentally studied. Due to its advantages such as compactness, easy integrity, intelligent operation, rapid heat storage and dissipation rates, and higher overall utilization efficiency, it may has extensive applications in near future in green heating of residential or commercial buildings, agricultural greenhouse heating, drying and other temperature control system. The solar radiation intensity, elevation angle of the equipment, ambient air temperature and flow-rate were considered experimentally as operating parameters. And the characteristics of the temperature distribution in different sections of the PCM in the HSUs were analyzed. The heat storage performance was studied at different solar radiation flux and elevation angle and the heat dissipation performance was conducted by changing ambient air temperatures and convective velocities. Experimental results showed that the optimum elevation angle of the apparatus was 60° (when used in July/August in the western part of Inner Mongolia). The more extensive the solar radiation, the higher heat storage capacity and rate of the STHSE were achieved. Higher ambient air velocity and lower temperature could significantly improve the overall heat dissipation performance and efficiency. At ambient air temperature of 18 °C and velocity of 6.0 m/s through the wind tunnel, the overall heat dissipation rate reached 414 W and the overall efficiency of heat dissipation was obtained as high as 97%.