Energy Efficient Two-Phase Microcooler Design for a Concentrated Photovoltaic Triple Junction Cell

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Alexander Reeser ◽  
Peng Wang ◽  
Gad Hetsroni ◽  
Avram Bar-Cohen

The potential application of an R134a-cooled two-phase microcooler for thermal management of a triple junction solar cell (CPV), under concentration of 2000 suns, is presented. An analytical model for the triple-junction solar cell temperature based on prediction of two-phase flow boiling in microchannel coolers is developed and exercised with empirical correlations from the open literature for the heat transfer coefficient, pressure drop, and critical heat flux. The thermofluid analysis is augmented by detailed energy modeling relating the solar energy harvest to the “parasitic” work expended to provide the requisite cooling, including pumping power and the energy consumed in the formation and fabrication of the microcooler itself. Three fin thicknesses, between 100 μm and 500 μm, a variable number of fins, between 0 and 9, and 5 channel heights between 0.25 mm and 3 mm, are examined for a R134a flow rate of 0.85 g/s to determine the energy efficient microcooler design for a 10 mm × 10 mm triple junction CPV cell.

Author(s):  
A. Reeser ◽  
P. Wang ◽  
A. Bar-Cohen ◽  
G. Hetsroni

This paper investigates the potential application of an R134a-cooled two-phase micro/mini-cooler for thermal management of a triple junction solar cell under 2000 suns concentration. An analytical model for the triple-junction solar cell temperature based on prediction of two-phase flow boiling in mini/microchannel coolers is developed and exercised with empirical correlations from the open literature for the heat transfer coefficient, pressure drop, and critical heat flux. The thermofluid analysis is augmented by detailed energy modeling, using two uniquely defined coefficient of performance metrics — COP relating the solar energy harvest to pumping power consumption and COPT relating the solar energy harvest to the “parasitic” work expended to provide the requisite cooling, including pumping power and the energy consumed in the formation and fabrication of the microcooler itself. Three constant fin thicknesses of 100μm, 300μm and 500μm are examined for a range of R134a flow rates and geometries to determine the energy efficient design for a 10mm×10mm triple junction CPV cell. The results reveal that two-phase cooling of CPV’s can achieve very high COPT values, substantially exceeding 104 for much of the design space of interest, though the energy efficiency is dependent on microcooler geometry and the number or pitch of the microcooler channels.


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Fahad Al-Amri ◽  
Tapas Kumar Mallick

A numerical heat transfer model was developed to investigate the temperature of a triple junction solar cell and the thermal characteristics of the airflow in a channel behind the solar cell assembly using nonuniform incident illumination. The effects of nonuniformity parameters, emissivity of the two channel walls, and Reynolds number were studied. The maximum solar cell temperature sharply increased in the presence of nonuniform light profiles, causing a drastic reduction in overall efficiency. This resulted in two possible solutions for solar cells to operate in optimum efficiency level: (i) adding new receiver plate with higher surface area or (ii) using forced cooling techniques to reduce the solar cell temperature. Thus, surface radiation exchanges inside the duct and Re significantly reduced the maximum solar cell temperature, but a conventional plain channel cooling system was inefficient for cooling the solar cell at medium concentrations when the system was subjected to a nonuniform light distribution. Nonuniformity of the incident light and surface radiation in the duct had negligible effects on the collected thermal energy.


2015 ◽  
Vol 8 (1) ◽  
pp. 106-111 ◽  
Author(s):  
Zilong Wang ◽  
Hua Zhang ◽  
Wei Zhao ◽  
Zhigang Zhou ◽  
Mengxun Chen

Research on automatic tracking solar concentrator photovoltaic systems has gained increasing attention in developing the solar PV technology. A paraboloidal concentrator with secondary optic is developed for a three-junction GaInP/GalnAs/Ge solar cell. The concentration ratio of this system is 200 and the photovoltaic cell is cooled by the heat pipe. A detailed analysis on the temperature coefficient influence factors of triple-junction solar cell under different high concentrations (75X, 100X, 125X, 150X, 175X and 200X) has been conducted based on the dish-style concentration photovoltaic system. The results show that under high concentrated light intensity, the temperature coefficient of Voc of triple-junction solar cell is increasing as the concentration ratio increases, from -10.84 mV/°C @ 75X growth to -4.73mV/°C @ 200X. At low concentration, the temperature coefficient of Voc increases rapidly, and then increases slowly as the concentration ratio increases. The temperature dependence of η increased from -0.346%/°C @ 75X growth to - 0.103%/°C @ 200X and the temperature dependence of Pmm and FF increased from -0.125 W/°C, -0.35%/°C @ 75X growth to -0.048W/°C, -0.076%/°C @ 200X respectively. It indicated that the temperature coefficient of three-junction GaInP/GalnAs/Ge solar cell is better than that of crystalline silicon cell array under concentrating light intensity.


2021 ◽  
Vol 2 (2) ◽  
pp. 100340
Author(s):  
Choongman Moon ◽  
Brian Seger ◽  
Peter Christian Kjærgaard Vesborg ◽  
Ole Hansen ◽  
Ib Chorkendorff

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 726
Author(s):  
Ray-Hua Horng ◽  
Yu-Cheng Kao ◽  
Apoorva Sood ◽  
Po-Liang Liu ◽  
Wei-Cheng Wang ◽  
...  

In this study, a mechanical stacking technique has been used to bond together the GaInP/GaAs and poly-silicon (Si) solar wafers. A GaInP/GaAs/poly-Si triple-junction solar cell has mechanically stacked using a low-temperature bonding process which involves micro metal In balls on a metal line using a high-optical-transmission spin-coated glue material. Current–voltage measurements of the GaInP/GaAs/poly-Si triple-junction solar cells have carried out at room temperature both in the dark and under 1 sun with 100 mW/cm2 power density using a solar simulator. The GaInP/GaAs/poly-Si triple-junction solar cell has reached an efficiency of 24.5% with an open-circuit voltage of 2.68 V, a short-circuit current density of 12.39 mA/cm2, and a fill-factor of 73.8%. This study demonstrates a great potential for the low-temperature micro-metal-ball mechanical stacking technique to achieve high conversion efficiency for solar cells with three or more junctions.


2019 ◽  
Vol 14 (1) ◽  
pp. 1-5
Author(s):  
Victor De Rezende Cunha ◽  
Daniel Neves Micha ◽  
Rudy Massami Sakamoto Kawabata ◽  
Luciana Dornelas Pinto ◽  
Mauricio Pamplona Pires ◽  
...  

Electrical current mismatching is a well-known limitation of triple junction solar cells that lowers the final conversion efficiency. Several solutions have been proposed to face this issue, including the insertion of a multiple quantum well structure as the intermediate junction’s active material. With a better matching in the current among the junctions, the total current increases, thus modifying the working conditions of the overall device. In this way, the InGaP top junction needs to be optimized to such new condition. In this work, numerical simulations were carried out aiming the enlargement of the electrical current density of an InGaP pn junction to achieve the proper current matching in triple junction solar cell for spatial applications. The optimized structure has been grown in a GaAs substrate and characterized as a single junction solar cell. Although the measured short circuit current density and conversion efficiency are still well below the theoretically predicted values, processing improvement should lead to adequate cell performance.


Author(s):  
Ali Radwan ◽  
Mohamed M. Awad ◽  
Shinichi Ookawara ◽  
Mahmoud Ahmed

Abstract In this study, a new design of double layer microchannel heat sink (DL-MCHS) has been monolithically fabricated using 3D metal printer and experimentally examined as a heat sink for concentrator photovoltaic (CPV) systems. Single phase liquid cooling using ethanol and flow boiling cooling using NOVEC-7000 coolant in the designed DL-MCHS are experimentally compared. The results proved that using the flow boiling cooling technique for the CPV systems attained a lower solar cell temperature with high temperature uniformity. In more details, flow boiling in counterflow (CF) operated DL-MCHS, attained a very low solar cell temperature close to the NOVEC-7000 boiling point with temperature uniformity of 0.2 °C over a wide range of coolant flow rate from 25–250 ml/hr.


Sign in / Sign up

Export Citation Format

Share Document