Performance analysis and working fluids selection of solar powered organic Rankine-vapor compression ice maker

摘要

To develop the organic Rankine cycle/vapor compression cycle (ORC/VCC) ice maker driven by solar energy, a thermodynamic model was developed, and four working fluids of R123, R245fa, R600a and R600 were selected and evaluated to identify suitable working fluids which may yield high system efficiencies. Besides, the effects of generation temperature and condensation temperature on the system performance were also analyzed. In terms of power efficiency and expander size, R600 and R600a are more suitable working fluids for ORC. Also, R600a and R600 are more appropriate working fluids for VCC in terms of pressure ratio and coefficient of performance. In terms of overall efficiency and ice production per square meter collector per day, R123 is most suitable working fluid for ORC/VCC. The generation temperature and condensation temperature have important effects on overall efficiency and ice production. There is always an optimal generation temperature at which overall efficiency and ice production can achieve the maximum values, while the generation temperature can be controlled by changing the mass flow rate of working fluid for ORC. In addition, the system performance and payback period should be comprehensively considered so as to decide to adopt air cooled or water cooled condenser due to having different condensation temperature.