Energy saving by a simple solar collector with reflective panels and boiler

Solar energy is absorbed by a simple and long-life solar collector set in a garden. The heated water is pumped to a shower directly or through a boiler. This paper focuses on the combination of high efficiency boilers with a simple collector. A tank of water pre-heated by ambient air and solar irradiation and/or a hot water reservoir can be added to the system in order to save fuel and reduce CO2 emission. The behaviour of the system has been simulated: water temperatures over a day are calculated as a function of the dimensions and the exposure of the pipes and of the surfaces of the reflective panels, of weather data and of water consumption. The numerical solution of the partial differential equation is obtained by a discrete approximation. The temperature field is approximated by values at discrete points where elements are concentrated. Numerical results of six different hot water systems with a simple solar collector are presented. The consumption of gas and CO2 emissions are compared with an instantaneous boiler, a combi-storage boiler and an electric boiler.