Thermodynamic Modeling of the Solar Organic Rankine Cycle with Selected Organic Working Fluids for Cogeneration

摘要

Fifteen (15) organic fluids were thermodynamically modeled to evaluate their fitness and performance as working fluids in an Organic Rankine Cycle (ORC) based cogeneration system. This article presents the exergy efficiency, thermal efficiency, solar power cycle efficiency, cogeneration efficiency, mass flow rate, heat input, required area of the solar collector and hot water production for the evaluated working fluids the low-temperature (90 and medium-temperature (125 solar organic Rankine cycles. Thermodynamic modeling was carried out using a commercial 1 kW scroll expander, two compact heat exchangers, a diaphragm pump and a solar collector. The article also describes the use of solar ORC technology for electricity generation and producing hot water as cogeneration. Commercial software, Engineering Equation Solver (EES), was used to calculate the operating parameters of the solar ORC. Of the 15 fluids investigated, R134a and R245fa were found to be the most appropriate working fluids for low-temperature and medium-temperature solar ORC cogeneration systems, respectively. RC318 and R123 offer attractive performance but require environmental precautions owing to their high ozone depletion potential (ODP) and high global warming potential (GWP). The article also estimates the hot water production from different working fluids for a period of one year in Busan, South Korea.