A photovoltaic thermal system with a complete contact between water and PV modules suitable for district heating and electric power generation

We studied the dynamic performance of a photovoltaic thermal system with a complete contact between water and PV module at zero reduced temperature (as defined by ASHRAE standard 93-2010). The system gives suitable electric-thermal performances and can be used in district heating and electric power generation systems. All experiments were done in Semnan city (northern part of Iran). The main part of the system involves a monocrystal photovoltaic module (used also as the heat absorbing plate) attached to a simple water box. Water is used as the coolant fluid with complete contact with the PV module and causes lower temperatures at the module surface. In most cases, the thermal efficiency increases with time while the collector's heat loss decreases. The maximum and daily averaged reported thermal efficiencies of the PV/T system are 58% and 49%, respectively. The minimum electrical efficiency occurs at noon when the maximum solar radiation occurs, at the same time, it has the highest electrical power output of PV/T system and photovoltaic module. At noon, the electrical efficiencies of the proposed system are 15 to 21.5% more than the conventional photovoltaic modules. The maximum increment of 21.5% is obtained for the water flow of 0.0161 kg/s.