COMPRESSING AIR IN A TANK PARTIALLY FILLED FROZEN WATER AND ITS USE TO DRAIN WATER FROM SOLAR COLLECTORS

Abstract

The use of the effect of increasing the volume of ice when freezing water to compress the air in a tank partially filled with water is considered. The aim of the study is to create conditions for the movement of the ice surface and determine the final air pressure after freezing water. A method of air compression has been developed and theoretical and experimental studies of the final air pressure have been performed. Experimental tests of a patented method of air compression with the provision of a movable ice surface by applying thermal insulation to the air chamber at the top of the tank were carried out. For this purpose, two air compressors of different sizes are made using cold air and a mixture of ice and salt. Obtained excess air pressures from 0.3 to 0.5 bar. The thermodynamic analysis of the process is carried out. The equation for determining the pressure at complete freezing of water, with a constant cross-section of the air compressor is obtained. Compression calculations are close to experimental data. Studies have shown the real technical possibility of air compression when water freezes in a rigid sealed tank and its use for automatic drainage of water from solar panels at the onset of frost. 1. The proposed and experimentally investigated method of ensuring the movement of the ice surface relative to the walls of the tank when compression of the air in the tank, by thermal insulation of the airspace. Obtained thermodynamic analysis of the equation for the final pressure of the air compressed by ice. When using a tank with a constant horizontal section, the final pressure does not depend on the area of ​​the cross section and increases with increasing water level. The experiments on two installations showed that excess pressure reaches 0.3 - 0.5 bar. Freezing water tank is proposed to be used as a temperature sensor, and compressed air can drive a direct action valve. Calculations of water freezing time for compression of the air showed its significant reduction with the growth of the tank coefficient.