Optimization of a concentrating photovoltaic thermal (CPV/T) system used for a domestic application

In this paper the design and model of a concentrating photovoltaic thermal (CPV/T) system are studied in order to size it and to optimize its electrical and thermal performance when it is used to satisfy the electric, heating and cooling loads of a domestic user. The choice and sizing of the CPV/T system components are first of all considered. The reflective optics with parabolic mirror concentrators of point-focus type and the triple-junction cells (InGaP/InGaAs/Ge) assembled with a dual axis tracker, are used in order to obtain a high concentration system. An active cooling system of the photovoltaic cells is also considered. The CPV/T system allows to obtain thermal energy at high temperature for the absorption heat pump working and to satisfy the cooling load. The model analyzes the CPV/T system working in terms of: direct normal irradiance, cell efficiency, module electric and thermal efficiency, thermal and electric energy provided by cell and module, cell and cooling fluid temperatures. Besides, in each working condition the value optimized of the concentration factor able to decrease the CPV/T system size and to provide a fluid outlet temperature that satisfies the thermal and cooling demands, is determined. Finally, the energy and economic convenience of the CPV/T system compared to a traditional system is also evaluated.