Square solar updraft tower coupled phase change material: An experiment

Abstract

Solar updraft tower is a low-cost heat collection ventilation power generation technology in solar heat utilization technology, which has high research potential and application value. However, the traditional circular solar updraft tower has some problems, such as low thermal efficiency, short working time, and unstable heat collection performance, which are caused by ambient crosswind disturbance and low heat capacity of the absorber. Therefore, this study designed a new square one-sided inlet solar updraft tower to prevent most of the heat from being lost through the ambient crosswind. At the same time, a phase change paraffin thermal storage unit was coupled in the absorber, which could reduce the temperature field fluctuation of the device and extend the working time by releasing latent heat when the solar irradiance decreased. Control experiments were conducted on the two processes. The test results show that the working time of the coupled new device is at least one hour longer than that of the square solar updraft tower without phase change material. The average temperature difference between the inlet and the external environment after the solar radiation drops at 17:00 is 79.12% higher than that of the traditional circular solar updraft tower of the same size, and the average instantaneous heat collection efficiency is 99.98% higher. While the effectiveness of the improved solar updraft tower is proved, the economic analysis of the integrated application of the single-side inlet solar updraft tower on the agricultural solar greenhouse is made. The carbon emission reduction of at least 2.144 tons in the year of using this system, and the construction cost is saved about 1330USD. The use of the system will reduce carbon emissions by at least 2.144 tons per year, save at least 2.30 tons of standard coal, and save construction costs of about 1330 US dollars. The research can provide theoretical and technical support for the efficient commercial application of solar updraft towers.