Determination of heat-transfer agent consumption and efficiency of a thermosyphon water-heating system with the flat-plate solar collector

The article presents the results of the empirical research studying the solar collector with natural circulation of a heat-transfer agent in the Ural region. Using the equation of heat balance for the collector, as well as the dependence of the heat-transfer agent density alteration on its temperature and the system of equations describing hydraulic resistance of the solar unit, the expression for consumption of the heat-transfer agent in the contour depending on the basic design, thermophysical and operating parameters which characterize the operation of the solar collector under natural circulation of the heat-transfer agent is obtained. Dependences for calculation of the flat-plate solar collector efficiency used under natural circulation of the heat-transfer agent in the diurnal operation cycle are proposed.