NUMERICAL SIMULATION OF THE AIR FLOW AROUND THE ARRAYS OF SOLAR COLLECTORS

This paper deals with the numerical simulation of air flow around the arrays of flat plate collectors and determination of the flow field, which should provide a basis for estimating a convective heat losses, a parameter which influences their working characteristics. Heat losses are the result of the reflection on the glass, conductive losses at the collector’s absorber plate, radiation of the absorber plate and convective losses on the glass. Wind velocity in the vicinity of the ab-sorber plate depends on its position in the arrays of collectors. Results obtained in the numerical simulation of flow around collectors were used as boundary conditions in modeling of thermal-hydraulic processes inside the solar collector. A method for coupling thermal-hydraulic processes inside the collector with heat transfer from plate to tube bundle was developed, in order to find out the distri-bution of the temperature of the absorber plate and the efficiency of the flat plate collectors. Analyses of flow around arrays of collectors are preformed with RNG k-ε model. Three values for free-stream velocity were analysed, i. e. 1 m/s, 5 m/s, and 10 m/s, as well as two values for the angle between the ground and the col-lector (20° and 40°). Heat transfer coefficient was determined from the theory of boundary layer. Heat transfer inside the plate cavity was analyzed assuming con-stant intensity of radiation. Key words: solar collector, heat losses, turbulent flow, CF