Modeling and energy analysis of a linear concentrating photovoltaic system cooled by two-phase mechanical pumped loop system

Abstract

Generally, the majority of the linear concentrating photovoltaic (LCPV) systems incorporated with active cooling systems use liquid water pump loop or conventional vapor compression refrigeration system. In this study, a new cooling system, so-called two-phase mechanical pumped loop (TMPL), is proposed to be used with LCPV system. The excess heat from photovoltaic (PV) cell is used to heat up water stored in a tank for residential purposes. The case study is Bogota in Colombia and we develop a dynamic simulation model for the LCPV-TMPL system. The design parameters of the TMPL system are the flow volumetric rate and saturation temperature of the refrigerant as well as the tube length of the condenser. Moreover, low global warming potential (GWP) refrigerants such as R1234yf and R1234ze(E) were evaluated, both showing the same performance compared to R134a. The results showed that the use of TMPL system to eliminate the generated heat of PV cell improves its temperature stability and efficiency. It also shows how the proposed model can be used to design the thermal/photovoltaic system for a local, showing also the expected performance before the system installation. In the case study region, the LCPV-TMPL system, using four PV cells with 5 m × 10 mm, produces power with an average monthly of 2 kW with a peak of 5 kW under average and peak monthly solar radiation of 400 W/m2 and 600 W/m2, respectively. The storage tank can heat up 2.2 m³ water per day from 8 °C to approximately 28 °C, in an average sense. This means that the LCPV-TMPL system could save 9000 kWh and 1900 kWh per year in electricity and thermal energies (water heating). This system can be used locally with low or medium solar radiation and cold weather.