Energy and exergy based study on a box type solar cooker coupled with a Fresnel lens magnifier

Abstract

ABSTRACT The variation of energy and exergy efficiency of a Box-type solar cooker (BTSC) incorporated with a Fresnel lens magnifier (FLMG) is evaluated in this study. The comparison in energy and exergy efficiency was investigated in the absence and presence of the FLMG to determine the efficiency variation of the BTSC by addition of the FLMG. With the implementation of FLMG, the average values of energy and exergy efficiencies had increased by 10% and 8.52%, respectively. The magnitude of energy efficiency with and without FLMG decreased with time, whereas the exergy efficiency enhanced with time for both cases. The manuscript discusses the effect of different thermodynamic parameters like temperature difference, energy and exergy output, absorber mean plate temperature, and heat losses in the modified cooker. The total heat loss coefficient ranged from 5.48 to 8.44 W/m2K and depended on the variation of wind velocity. The maximum heat loss and mean plate temperature were found to be 120 kJ and 128.3°C, respectively. The time for sensible heating was reduced by 16 mins by the implementation of the FLMG. The addition of the lens showed an increase in the Area concentration ratio (AR) of the BTSC by 48.7%. By comparing the cost and energy usage of LPG (Liquefied Petroleum Gas), the payback period and the quantity of carbon dioxide reduced per month were calculated as 3.19 years and 8.265 kg, respectively.