COMPARISON OF WATER HEATING BY SOLAR COLLECTORS AND PHOTOVOLTAIC PANELS

Amount of presently mainly used fossil energy resources on the earth are limited and its impact on the earth environment is negative. Therefore, scientific research on replacing them with alternative energy like solar is important. Usually in practice, solar radiation for domestic water heating by solar collectors and production of electric energy by photovoltaic (PV) panels is used. Obtained by solar panels electric energy for water heating also can be use. The aim of the research is to make out the more preferable method for water heating by solar radiation particularly in weather conditions of Latvia. There are some advantages and disadvantages for each of them analyzed in the paper. Our research has shown that, at the same intensity of solar radiation, the efficiency of solar collectors is higher while the heated water temperature in the system's hot water tank is lower, and at higher ambient air temperature as well, but opposite to this, efficiency of PV panels is higher at lower ambient air temperature. Electricity produced by PV panels, using an electric resistance heaters heat water independently of its temperature. The amount of heat energy transferred from a solar collector by heat carrier to the hot water tank depends on the temperature difference between the heat carrier and heated water. The method of investigation corresponds to the goal of investigation, the effectivity of solar collectors and solar panels of different design and construction has analyzed in the paper.