Energy performance analysis of a forced circulation solar water heating system equipped with a heat pipe evacuated tube collector under the Mediterranean climate conditions

This work represents the energy performance analysis during the annual time period of a forced circulation solar water heating system equipped with a heat pipe evacuated tube collector having an aperture area of 1.476 m² under the Mediterranean climate conditions. For the purpose, recorded data from a field-trial installation are exploited. The recorded data obtained every minute are used to perform the energy analysis during an annual period. The analysis is performed by using mathematical models and by representing the results for each month. Monthly values of measured parameters and calculated quantities offered a clear view regarding the operation of the considered field-trial installation for this climate region. For an annual irradiation on solar collector plane of 2,212 kWh/year, it was noticed that the annual useful heat gain for the heat pipe evacuated solar tube collector, the useful energy delivered by the solar circuit to the storage tank, and the delivered energy to the thermal consumer were 1,345 kWh/year, 1,311 kWh/year, and 1,009 kWh/year, respectively. The annual efficiency for the heat pipe evacuated solar tube collector was 0.62, while for the forced circulated system was 0.516. Also, the annual energy balance of the system obtained from the calculation is built.