Investigation of the performance of modified organic Rankine cycles (ORCs) and modified trilateral flash cycles (TFCs) assisted by a solar pond

Solar pond is a type of solar collector that stores solar energy in the form of heat. The solar pond can be used as a low-temperature heat source for electricity generation. In this paper, to find the most suitable power cycle for power generation from the solar pond, the performance of the Organic Rankine Cycle (ORC), Trilateral Flash Cycle (TFC) and their modified forms with an open feed liquid heater and an internal heat exchanger for different working fluids was investigated. Water was considered as the heat transfer fluid which transfers the stored heat from the solar pond to the working fluid of the cycle. The results indicate that in all cases, the energy and exergy efficiency of the ORC is higher than those of the TFC. The regenerative ORC with both open feed liquid heater and internal heat exchanger that works with R123, as the working fluid, has the best performance and the highest output power among all the examined cycles. By reducing the mass flow rate of the heat removal working fluid, energy and exergy efficiency of the cycle increased. The optimum mass flow rate in which the maximum power is generated is 0.1082 kg/s and 0.1224 kg/s for the ORCs and the TFCs that work with R123, respectively.