Optimization of a novel combined cooling, heating and power cycle driven by geothermal and solar energies using the water/CuO (copper oxide) nanofluid

In this paper, a novel micro CCHP (combined cooling, heating and power system) driven by solar and geothermal energies is modeled and optimized. The CCHP system integrated with flat plate collectors is based on an ORC (organic Rankine cycle) with an ejector refrigeration cycle. The CuO (copper oxide) nanoparticles suspended in pure water are applied as the heat transfer medium inside the collector subsystem. NSGA-II (Non-dominated Sort Genetic Algorithm-II) is individually employed to achieve the final solutions in the multi-objective optimization of the system for four working fluids including R134a, R423A, R1234ze and R134yf from the energy, exergy and exergoeconomic viewpoints. The multi objective optimization results indicate that the best fluid from the energy and exergy viewpoints is R134a with 30.73% and 1.33% improvement, respectively relative to the base case. Also, R423A is the best fluid with the minimum total heat exchangers area so that the maximum nanoparticles volume fraction is required compared with other studied fluids. Furthermore, the best fluid from the exergoeconomic as well as environmental viewpoints is R1234yf with minimum total product cost rate of 5267.91 $/year. In this case, the maximum collector area and the minimum nanoparticles volume fraction are needed compared with other studied fluids. (C) 2015 Elsevier Ltd. All rights reserved.