ABSTRACT
In this paper, the performance of a water-cooled PV-thermal (PV/T) hybrid system with low concentrating aluminium compound parabolic concentrators (CPCs) is discussed. The advantage of hybrid systems is their high total efficiency. By using concentrating hybrid systems, the cost per kWh is reduced due to simultaneous heat and electricity production and a reduced cell area. The thermal energy delivered from the module will fully compensate for the cost of the concentrating element and more electricity per cell area is produced. This technology is promising for future reduction of the cost of PV electricity. During 1999, a concentrating hybrid system with a geometric concentration ratio of 4X and 0.5 kWp electric power was built at Vattenfall Utveckling, Älvkarleby, Sweden (60.5° N, 17.4° E). The yearly output is 250 kWh of electricity per square meter solar cell area, compared to 125 kWh for a conventional module, and 800 kWh of heat per square meter solar cell area. By using optimised reflectors and cells with lower series resistance, the yield could be further increased by 20%.
