Design and Evaluation of a New Desalination System Using Heat Pump

Global demand for freshwater is increasing rapidly due to the significant soaring of the rate of population growth. However, the available freshwater is already a scarce resource and does not satisfy the global increasing need of fresh water. Desalination is an efficient technique to provide freshwater supplies. However, desalination is an energy-intensive technology. Therefore, the cost of fresh water produced by this technology is strongly based on energy cost which is rising with dwindling oil supplies. The integration of humidification-dehumidification system and heat pump presents an impressive method of desalination. From an energy point of view, the heat pump provides a high overall efficiency as it makes a high recovery of both mass and heat. The objectives of this research include design and performance evaluation of a heat pump system for a small-capacity desalination unit. After the experiment setup was built up, a series of experiments were conducted under the meteorological conditions of Iraq to evaluate the system performance under different applications and operating conditions. Desalination is carried out in Humidification-Dehumidification and Heat Pump technique. The heating part was incorporated with the condenser side of the heat pump and the cooling part was connected in parallel to the evaporator unit of the heat pump. In the integrated system the maximum productivity was found 2.46 kg/hr and the maximum performance ratio, 2.83. The minimum power consumed in desalination process was found 869kJ/kg. The maximum coefficient of performance of the heat pump system was found to be 4.68. This result is an important achievement in reducing the energy consumed in the desalination process in small-capacity desalination units.