A sustainable exergy model for energy-water nexus in the hot regions: integrated combined heat, power and water desalination systems

摘要

Water scarcity is a worldwide concern for Earth citizens. Finding new methods for water concentration is essential for the extension of life. The water issue is more intense in the regions with a warm to the tropical environment. Considering the cooling demand of these regions, which consequently requires excess energy to satisfy the cooling load, having a thermal system to support three concerns of the water, cooling, and power would be the key for the warm/hot weather areas. In the present study, a novel model by integration of gas turbine power cycle with a solar parabolic collector, a steam turbine, heat recovery, steam generator, multi-effect desalination, and absorption chiller is proposed. The suggested model is optimized through developing a comprehensive multi-objective function to maximize the exergy efficiency and minimize the cost. Using the genetic algorithm method, the model is optimized based on six design parameters such as condenser pressure, number of solar parabolic through collector rows, gas turbine and steam turbine inlet temperature, high and low pressure, high- and low-pressure pinch points. The final optimal design point of this cycle enables the overall exergy efficiency of 36.16% and 188.43 $ h(-1) of the total cost rate value; also, this integrated energy system provides the net electrical generation of 5.18 MW and the cooling load rate of 406.18 KW and generates 2.57 kg s(-1) of desalinated water. In this novel cycle solar energy is used for preheating the inflow of the combustion chamber. A dual pressure heat recovery exploits thermal energy of flue gas, which runs both desalination and multi-effect absorption system and circulates in simultaneous water and cooling load generation. Finally, by utilizing the genetic 1 algorithm, the optimal system is developed.