Experimentation on solar-assisted heat pump dryer: Thermodynamic, economic and exergoeconomic assessments

Abstract

The convective closed-loop solar-assisted heat pump dryer (batch type) has been designed, fabricated and experimentally investigated for both simple heat pump drying (HPD) and solar-assisted heat pump drying (SAHPD) modes. The banana chips have been dried up to moisture content of 11.5% for both modes. The next-generation environmental-friendly refrigerant R1234yf has been used in the heat pump cycle. Various thermodynamic, exergoeconomic and economic performance parameters have been evaluated and compared for HPD and SAHPD. Both exergy and energy efficiencies are found better in the case of SAHPD. The system coefficient of performance, moisture removal from the product, drying rate and specific moisture extraction rate are found better for the SAHPD than the HPD. The average drying rates of HPD and SAHPD are found 0.205 and 0.342 kg/kg min, respectively. The estimated payback period of the SAHPD instead of HPD is 3.9 years. The exergoeconomic factor is found lowest for the expansion device for both HPD and SAHPD with estimated values of 0.1335 and 0.2003, respectively. The components that need more improvement are evaporator and expansion device based on exergoeconomic factor. On the basis of the present study, it can be concluded that the SAHPD system performs better in all respects.