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Finite time thermodynamic analysis and optimization of solar-dish Stirling heat engine with regenerative losses

Sharma Arjun (Mechanical Engineering Department, Institute of Technology Banaras Hindu University (B.H.U.), Varanasi, India)
Shukla S.K. (Mechanical Engineering Department, Institute of Technology Banaras Hindu University (B.H.U.), Varanasi, India)
Rai Kumar Ajeet (Department of Mechanical Engineering and Applied Mechanics Sam Higinbottom Institute of Agriculture, Technology and Sciences Allahabad, U.P., India)

The present study investigates the performance of the solar-driven Stirling engine system to maximize the power output and thermal efficiency using the non-linearized heat loss model of the solar dish collector and the irreversible cycle model of the Stirling engine. Finite time thermodynamic analysis has been done for combined system to calculate the finite-rate heat transfer, internal heat losses in the regenerator, conductive thermal bridging losses and finite regeneration process time. The results indicate that exergy efficiency of dish system increases as the effectiveness of regenerator increases but decreases with increase in regenerative time coefficient. It is also found that optimal range of collector temperature and corresponding concentrating ratio are 1000 K~1400 K and 1100~1400, respectively in order to get maximum value of exergy efficiency. It is reported that the exergy efficiency of this dish system can reach the maximum value when operating temperature and concentrating ratio are 1150 K and 1300, respectively.

Keywords: Solar parabolic dish collector, Solar-driven Stirling engine, Finite-rate heat transfer, Exergy efficiency of dish system