Thermodynamic investigation and optimization of a heat pump coupled open-air, open-water humidification dehumidification desalination system with a direct contact dehumidifier

This paper focuses on a novel heat pump powered desalination system, in which the heat pump is coupled into the humidification dehumidification desalination subsystem with open-air, open-water configurations. Based on the conservation equations in accordance with the flow streams within the system, thermodynamic investigations, at the energetic and entropic viewpoints, are conducted. Thereinto, parametric analysis of the HPPDS is first achieved to assess the influence extents from the critical conditions, and then the thermodynamic optimization based on the algorithm of particle swarm optimization is also completed. The research results indicate the best system performance reaches 89.27 kgh⁻¹ for the water production and 4.17 for the gained-output-ratio. The performance of the heat pump powered desalination system is very sensitive to the alternation of the prescribed parameters, except the dehumidification effectiveness. Finally, the maximum water production and gained-output-ratio can be optimized to 150.75 kgh⁻¹ and 8.12, respectively, and a fully coupled heat pump powered desalination system is acquired without an auxiliary heater. With respect to the economic performance, the cost of the fresh water is gained as 0.016$L⁻¹ at the optimized conditions.