Improving the Performance of Systems with Solar Water Collectors Used in Domestic Hot Water Production

This paper makes an analysis of the optimal operation of the systems with flat solar collectors in closed circuit, to convert the solar energy in thermal energy - hot water (DHW - domestic hot water), by comparing the various models from the literature. To improve the performance of thermal solar collectors, we follow to maximize the energy as: (i) useful heat, (ii) heat extracted and (iii) outlet water temperature of the solar collector. The control parameter in DHW system is mass flow rate. The second objective of this paper is to show how to make a properly sized of the storage tank from the DHW system. Analysis was performed on meteorological data from 3 July 2009, with medium relative sunshine value σ=0.4÷0.7.