Dynamic simulation of solar thermal collectors for domestic hot water production

In this paper a system for the Domestic Hot Water (DHW) production based on solar collectors is analyzed by means of a dynamic approach based on a Simulink model and by using the F-chart method, able to evaluate system performances on a monthly basis. Following the dynamic approach, it is possible to evaluate hour by hour the energy collected by the solar panels and the temperature of the hot water produced by the system, by taking into account the impact of different daily DHW consumption profiles on the percentage of thermal energy produced by the solar collector (Solar Coverage Factor, SCF). The comparison between the prediction made both by using the Simulink model and the F-Chart method in terms of SCF is shown by taking into account the effect on SCF of the typology of solar collector (unglazed, glazed and evacuated collectors), of the storage tank volume connected to the solar panels and of the hourly DHW consumption profile. The results point out that SCF is strongly dependent on the daily DHW consumption profile, which cannot be taken into account in a quasi-static approach like the F-chart method.