Thermodynamic investigation of water generating system through HDH desalination and RO powered by organic Rankine cycle

Abstract

The present study proposed the water generating system through humidification-dehumidification desalination unit and RO powered by organic Rankine cycle to generate both power and drinking water from the waste heat of Naval Ship by using a low-temperature organic Rankine cycle. Waste heat from the naval ship is used in order to run the topping cycle namely the organic Rankine cycle for power generation which operates the RO system for drinking water. A water-heated humidification dehumidification (HDH) desalination unit is also integrated with the organic Rankine cycle system to produce additional freshwater. The mass and energy balance equations are designed to analyze the thermodynamic performance of the cogeneration of the power-water system at the designed conditions. Suitable working fluids for the organic Rankine cycle are chosen on the basis of thermophysical properties i.e. lower boiling point, critical temperature & pressure and global warming potential. Furthermore, the impact of various vital parameters like extraction pressure, vapor extraction ratio, condenser temperature, turbine inlet pressure, etc. on the performance. It was founded that the impact of extraction parameters on the cycle, the net power, total efficiency and water production is 16.74 kW, 42.10% and 75.18 kg h−1 respectively. The extraction ratio variation causes the improvement in the water production and power generation and lower extraction ratio has better results. The RO System used is direct mechanical coupling which uses the power to run the system and produces the water, 2.4L of drinking water is produced using 16.74 kW power, respectively.