The growing global population, along with the expansion of industrial an‎d agricultural activities in recent years, has exacerbated the issue of freshwater scarcity. The. humidification-dehumidification (HDH) process has emerged as a promising desalination method due to its moderate energy consumption. This study investigates the performance enhancement of the HDH process in a pre-designed an‎d fabricated closed-air, open-water configuration system. The research focuses on examining the effects of varying the temperature of the inlet water an‎d air to the humidifier, as well as eva‎luating the performance of different condenser types under diverse operating conditions. The primary challenge addressed in this study is the improvement of the condensation process in the dehumidifier section an‎d the enhancement of freshwater production. To assess the systemʹs performance, a series of experiments were conducted by varying parameters such as air flow rate, temperature, mass flow rate of the cooling fluid through the condenser, an‎d the temperatures of the inlet air an‎d water streams to the condenser. The experiments were carried out under various blower opening levels, resulting in air flow rates ranging from 53 to 62 kg/h. Two cooling fluid mass flow rates were tested (96.9 kg/h an‎d 252 kg/h), an‎d based on the season of testing, two coolant temperature ranges were used: 20–21°C an‎d 24–26°C. Additionally, four different air inlet temperatures to the condenser were eva‎luated. The results revealed that a 15% increase in the air mass flow rate led to a 24% rise in freshwater production. At a constant air mass flow rate, increasing the humid air temperature by approximately 12°C resulted in a 115.8% increase in freshwater yield an‎d a 79.5% improvement in the gain output ratio (GOR). Furthermore, increasing the air mass flow rate by 15% an‎d raising the humidifier inlet air temperature by 12°C enhanced the absolute humidity by 85.8%. Moreover, increasing the cooling fluid mass flow rate through the condenser an‎d reducing its temperature by approximately 5°C led to respective increases in freshwater production by 103.4% an‎d 36.4%. Under optimal conditions (air flow rate of 61 kg/h an‎d condenser inlet air temperature of 53°C), the system efficiency (η) increased by up to 48%. According to the findings, the highest freshwater output in this system is achieved under high humid air temperatures entering the condenser, increased air mass flow rate, an‎d lower coolant temperatures. Although the systemʹs performance improved significantly, the economic an‎d energy feasibility of these enhancements remains uncertain, as achieving them may require substantial energy an‎d resource inputs, potentially reducing net efficiency an‎d undermining economic viability.

محسن نصراصفهاني

مهدي ستاري نجف آبادي , احمد محب