Performance investigation on a frost-free air source heat pump system employing liquid desiccant dehumidification and compressor-assisted regeneration based on exergy and exergoeconomic analysis

Frost build-up on the evaporator of air source heat pump severely deteriorates the heat transfer and subsequently reduces the performance of the system. Combining liquid desiccant dehumidification with heat pump system is an efficient strategy to achieve frost-free operation by dehumidifying the inlet air during winter in humid areas. In this paper, detailed energy, exergy and exergoeconomic analyses are performed for a frost-free air-conditioning system with integrated liquid desiccant dehumidification and compressor-assisted regeneration, in which the diluted liquid desiccant can be efficiently regenerated under low temperature condition. Parametric studies are conducted to appraise the influence of the important operation parameters on the performance of the proposed system. Then the hybrid system is optimized and compared from the exergoeconomic perspective. It is found that, the first and second largest exergy destructions take place in the regenerator and dehumidifier, which can be improved by increasing the investment costs. When the proposed system is optimized based on the exergoeconomics, the coefficient of performance and exergy efficiency increase by 13.02% and 12.73%, respectively. The total product unit costs can decrease by 12.64% compared to that under the basic operation condition.