Numerical investigation of a heat pipe receiver for the solar dish collector humidification–dehumidification desalination system

Regarding the increasing demand for freshwater supply worldwide in coming years, solar desalination systems have good potential for tackling this challenge. Solar humidification–dehumidification desalination system is a technology that can effectively supply the water demand for rural areas with brackish water resources. Parabolic dish collectors with cavity receivers are one of the heat source options for this desalination technique. The main challenge for a dish collector with a cavity receiver-based desalination system is the low freshwater production rate. The current research aims to utilize a heat pipe receiver in a dish collector to heat brackish water to the required temperature for the humidification–dehumidification desalination process. According to the results, the flow rate of the inlet brackish water varied between 0.3 and 0.4875 L min⁻¹, while the temperature of the outlet brackish water of the heat pipes ranged from 60.20 to 64.24 °C. Moreover, the results show that with the application of a heat pipe receiver, a maximum thermal efficiency of 35.79% was determined in the parabolic dish collector system for water sample with 10,600 μS cm⁻¹ salinity. Moreover, 35.50, 35.30, and 35.08% were calculated for the average thermal efficiency values of the parabolic dish collector system for water samples with 3880, 10,600, and 21,500 μS cm⁻¹ salinity, respectively. Also, the maximum outlet temperature for the brackish water samples with 3880, 10,600, and 21,500 μS cm⁻¹ salinity were 63.98, 61.51, and 64.37 °C, respectively. According to the findings, heat pipe receivers lead to higher freshwater production rates than conventional cavity receivers.