Power Output Of Hybrid System Research Articles

Thermodynamic evaluation of irreversibility and optimum performance of a concentrated PV-TEG cogenerated hybrid system

In this paper, the thermodynamics evaluation of an irreversible CPV-TEG cogenerating system, having Siemens SP75 PV module and commercially available Bi2Te3 TE module, has been investigated for wide solar spectrum to encompass the winter and summer solar radiation. Modeling and simulation of the hybrid system has been carried out to understand the feasibility of the system and to determine the irreversibilities present in the hybrid system. The irreversibilities or exergy destruction caused by the irreversible conversion process of solar energy into electricity are calculated using exergy analysis based on second law of thermodynamics. The various exergy losses occurring in the hybrid system have been calculated using exergy analysis. The effects of the incident solar irradiance varying in a wide range from 100 W/m2 to 1000 W/m2, TEG junction temperature ratio, concentration ratio, TEG current, Thomson coefficient, irreversibilities or exergy destruction and the incoming solar radiation exergy have been studied. The results showed that the Thomson effect has adverse effect on the performance of the hybrid system and the irreversibilities increase with increase in concentration ratio, C. Further, the power output of hybrid system increases by 86% as C increases from 1 to optimum value of 3 and the exergy efficiency is higher than the energy efficiency by 8%. The higher values of the irreversibilities make the system less inefficient and therefore, significant improvements are required because the elevated temperature could result in hot spots formation. The results of this analysis may be helpful in designing of practical CPV-TEG hybrid system.

Solar driven concentrated photovoltaic-thermoelectric hybrid system: Numerical analysis and optimization

In this study, a theoretical model of a concentrated photovoltaic-thermoelectric hybrid system has been developed based on first and second laws of thermodynamics and analysed in MATALB. A numerical method has been exploited to determine the temperatures of photovoltaic module (PV) and hot and cold side of thermoelectric generator (TEG) by iteratively solving the energy balance equations. The proposed study takes into account the effects of hot and cold side thermal resistances, thermoelectric properties, fill factor, geometry of thermoelectric module, load resistance and electrical current on the performance of the hybrid system. The results show that the optimum value of ratio of TEG load resistance to TEG internal resistance, m for maximum power output and efficiency of thermoelectric module is higher than unity. The concentration ratio should also be optimized to achieve maximum PV power output. For the fixed leg length of 5 mm and CG value of 1 kW/m2, the optimum m corresponding to maximum power output and maximum efficiency of the hybrid system is 0.5. The maximum power output and efficiency of the hybrid system increase by 5% as compared to the corresponding values of concentrated PV system. Moreover, at higher concentration ratios, the contribution of thermoelectric power to the power output of hybrid system is higher. Further, for other parameters fixed, the optimum value of CG for maximum power output of the hybrid system is 5.5 kW/m2 and it is 14% higher than the corresponding power output of CPV system alone. This improvement in the performance of hybrid system is added by the thermoelectric generator module. The results of this analysis incorporating the electrical and thermal contact resistances of thermoelectric device, may be helpful to envisage the design of a real photovoltaic-thermoelectric hybrid system.

Modeling and performance analysis of a concentrated photovoltaic–thermoelectric hybrid power generation system

In this study, a thermodynamic model for analysing the performance of a concentrated photovoltaic–thermoelectric generator (CPV–TEG) hybrid system including Thomson effect in conjunction with Seebeck, Joule and Fourier heat conduction effects has been developed and simulated in MATALB environment. The expressions for calculating the temperature of photovoltaic (PV) module, hot and cold sides of thermoelectric (TE) module are derived analytically as well. The effect of concentration ratio, number of thermocouples in TE module, solar irradiance, PV module current and TE module current on power output and efficiency of the PV, TEG and hybrid PV–TEG system have been studied. The optimum concentration ratio corresponding to maximum power output of the hybrid system has been found out. It has been observed that by considering Thomson effect in TEG module, the power output of the PV, TE and hybrid PV–TEG systems decreases and at C=1 and 5, it reduces the power output of hybrid system by 0.7% and 4.78% respectively. The results of this study may provide basis for performance optimization of a practical irreversible CPV–TEG hybrid system.