Bifacial photovoltaic (PV) cell technology is growing popular due to its ability to utilize sunlight from both the front and the rear surfaces. It produces more power output as compared to conventional PV system and makes effective use of the ground reflected albedo radiation. Optical concentrators are also added to enhance the incident flux on the receiver and increase the efficiency of system. The resulting concentrated photovoltaic (CPV) systems outperform their non-concentrated counterparts in terms of higher electrical power output and reduced required area of the cell but its application is restricted to low concentrations (CR \< 10) so far. In this work, a novel design of a medium CPV system (CR = 20) is analyzed that employs two poly-crystalline Si photovoltaic cells. Both cell are attached to an aluminium container, one on the top and second on the bottom of the container. Thermal regulation is passively achieved through phase change material (PCM), which is encapsulated in a 0.11 × 0.04 × 2.67 m^3^ aluminum container that acts as a heat sink. The bottom CPV cell, 15 mm wide, is exposed to uniformly distributed concentrated sunlight by using a reflecting type, non-ideal parabolic trough concentrator. A single-axis tracking system is considered to be installed with the concentrator. The top 100 mm wide PV cell receives non-concentrated sunlight and effectively utilizes the space on the top side.

A validated finite element based coupled optical, thermal and electrical model is used to analyze the system for the environmental conditions of Lahore, Pakistan (latitude: 31.6946°N and longitude:74.2441°E). Various PCMs are selected for analysis for one day of all months of a year to investigate their melting and regeneration behavior. Their thermal performance is compared to determine the most suitable PCM for proposed configuration. Selected PCMs include RT47, S-series salt, STL47, ClimSel^TM^ C48, RT54, RT60, RT62, and RT64 with melting temperatures in range of 41-65 ℃. Grid and time independence studies are carried out to determine the suitable number of elements and time step. The incident beam irradiance, ambient temperature and wind speed data is obtained from World Bank and a clear day of each month is selected for analysis.

The melt fraction results indicate that PCMs with melting point range 41-49 ℃ are well-suited to current configuration and location, as they melt entirely for most of the months of a year. The PCMs with higher melting temperature range (49-65℃) do not melt fully for all months and do not utilize their full thermal capacity. Thermal efficiencies are found to be highest for s-series salt followed by STL 47 and lowest for RT 54 and RT62 which can be attributed to the combined effect of melting temperatures and heat of fusion of the PCMs. The maximum combined average power from both the CPV and the PV cells is obtained for s-series salt for all months.


Thermal and Electrical Performance Analysis of a Novel Medium Concentration Dual Photovoltaic System for Different Phase Change Materials

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Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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