Thermal performance assessment of an evaporative condenser-based combined heat pump and humidification-dehumidification desalination system

A new design for heat pump integrated humidification-dehumidification (HDH-HP) desalination cycles was proposed in the current experimental study. An evaporative condenser was designed and fabricated instead of a separate humidifier, heater, and air/water-cooled condensers find in previous HDH-HP systems. Meanwhile, the air dehumidification process in this work directly occurred inside the heat pump evaporator. The effect of several operating parameters such as ambient wet-bulb temperature, spraying saline water and airflow rates, compressor speed, superheat, and evaporator saturation temperature control modes of the electronic expansion valve (EEV) on freshwater production and GOR were studied. Analyzing the experimental results indicated that the system productivity and GOR reached 1.08 kg/h and 2.00, respectively. Higher freshwater produced at decreased airflow rates and increased ambient wet-bulb temperatures, spraying water flow rate and compressor speeds. Moreover, it was observed that the system performance enhances at higher adjusted evaporator saturated temperatures and lower superheats in the EEV controller. The experimental data for cooling capacity, compressor power, and current consumption was in agreement with polynomials provided by the compressor manufacturer. Additionally, the cost of generated freshwater was obtained as 0.019 $/L.