The Principle Of Cooling Transformer And Its Application To Refrigeration System Driven By Low Grade Thermal Energy

Energy and environment are foundation and keys to the sustainable development of human society. They have become the worldwide concerned problems. The efficient utilization low-grade energy is recognized as one of the most important strategic missions which can relieve the energy sources problems and protect the environments. However, due to the low temperature feature of low-grade thermal energy, efficiency of traditional air conditioning driven by low-grade thermal energy is low and even hardly maintains its normal working condition. These features restricted the application and development of low-grade thermal energy in the refrigeration fields.It is well known that cooling capacity can be graded by its temperature, that is to say, the lower the temperature, the higher the grade of cooling capacity. It is more difficult to obtain higher grade cooling capacity than lower one. Based on the principle of thermodynamics and compared with the heat transformer, a cooling transformer driven by low grade thermal energy was introduced. It can be expected that a cooling transformer driven by low grade thermal energy may work efficiently.Theoretical research on the performance of cooling transformer driven by low grade energy was conducted. Based on the principle of cooling transformer, a simulation model of a new refrigeration system driven by low-grade energy was developed and a mathematical model for each component of the system is presented. The influences of the heating water temperature, cooling water temperature and inlet temperature of the cooled water to the evaporator on cycle performance were evaluated.A cooling transformer driven by low grade energy for experimental investigations was fabricated. The experimental results were obtained under constant flow condition. It indicated that the cooling transformer not only had higher value of refrigeration capacity and higher value of COP, but also the operating temperature range of low-grade energy is broadened, compared with the traditional absorption refrigeration system.Finally, based on the principle of cooling transformer and experimental results, some suggestions on the future researches were proposed.