One-day performance evaluation of photovoltaic-thermoelectric hybrid system

Almost all of the researches about the photovoltaic-thermoelectric (PV-TE) hybrid system focus on the steady-state performance assuming solar irradiance is constant (1000 W/m2) and ignoring the influence of changing solar radiation with time. In this paper, a theoretical model for obtaining the coupling system one-day performance is established. Detailed one-day changes in coupling system temperatures, powers, efficiencies are revealed. The thermal concentration ratio is discussed and is optimized to increase the one-day average efficiency. Influences of photovoltaic efficiency temperature coefficient, thermoelectric Z value, water cooling mass and velocity are discussed. The one-day performances of pure PV and PV-TE hybrid system are compared. The results show that the coupling system can obtain the highest one-day average efficiency by optimizing the thermal concentration ratio. The highest one-day average efficiency of the hybrid system decrease with the rise of the photovoltaic temperature coefficient and increase with the thermoelectric Z value augmenting. The mass of the cooling water has a remarkable positive effect on the hybrid system performance while the impact of the cooling water velocity is tiny. The hybrid system one-day capability is preferable to the pure PV system when the thermoelectric Z value is large or the photovoltaic temperature coefficient is small.