Multiobjective Optimization of a Tri-Generation Organic Rankine Cycle for Power, Freshwater and Heat: Suitable Mixture of Three Fluid

Improving the performance of a tri-generation organic Rankine cycle for the production of power, fresh water and heat using solar energy to respond to the needs in remote areas is very important. One of the effective factors in the performance of such a cycle is the thermodynamic behavior of its working fluid. Finding a suitable working fluid that has a good behavior on power generation, freshwater production and heat are of particular importance. This study aims to find an appropriate working fluid by analyzing, simulating, and optimizing a tri-generation Rankine cycle powered by solar parabolic trough collectors for simultaneous production of power, fresh water, and heat. The performance of this cycle is investigated with various mixtures of organic fluids R152a, R600a, and R1234yf which are categorized as wet, dry, and isotropic fluids, respectively. Therefore, first, a parametric study is conducted and followed by a multi-objective optimization for which power, fresh water, and heat are the objective functions. While the various mixture of these three working fluids are considered to be optimized. The results show that three-component mixture is more suitable for achieving three goals simultaneously, while if one of the objectives is considered, only one of these fluids should be used.