Performance Comparison of Rankine Cycle using Solar Energy and Supercritical CO₂ over Basic Rankine Cycle

The rankine cycle to convert heat into useful work has been investigated for many years. Use of solar energy and CO₂ is of great importance in reducing energy shortage and environment problems such as global warming, ozone depletion, and atmospheric pollution. A solar powered rankine cycle using supercritical CO₂ shows a higher potential than a basic rankine cycle, when considering heat source as solar collector and the heat transfer between heat source and working fluid (carbon dioxide) in the main heat exchanger. This is mainly due to better temperature glide matching between heat source and working fluid. The solar powered CO₂ cycle also shows no pinch limitation in the heat exchanger. This study compare the performance of solar powered rankine cycle with supercritical CO₂ recovering heat (high temperature heat and low temperature heat), which could be used for refrigeration, air-conditioning, hot water supply etc. in comparison to rankine cycle. The results obtained show that the solar powered rankine cycle using CO₂ works stably in a transcritical region, estimated power generation efficiency is 0.25 and heat recovery efficiency is 0.65.