열회수 이젝터를 적용한 냉동시스템의 성능특성에 관한 연구

Abstract

In this study, an analysis of a new form of refrigeration mechanism that added a regenerator and an ejector to the current vapor compression refrigeration system was undertaken as a new way of utilizing waste heat. An ejector which is suitable for the heat recovery ejector refrigeration system was developed in the performance factors analysis of the ejector refrigeration system. And a study on the operation and performance characteristics of the ejector refrigeration system was performed by applying the designed ejector. As results, compressor capacity was found to be a significant factor in the heat recovery ejector refrigeration system, and the probability of enhancing the performance of the system was confirmed by optimizing the compressor capacity and the size of the system's ejector nozzle. In the study of the performance factor of the ejector refrigeration system, the power consumption decreased as the pressure of the refrigerant discharged to the ejector outlet was higher than the ejector mounted a converging tee system. The COP of the system with the ejector installed was 25% higher, and as the ejector was installed in the system, it was found that it can help to improve the performance of the system. An analysis on the ejector refrigeration system's operation and performance characteristics according to the temperature of the heat source supplied to the regenerator found that the optimum temperature of the heat source provided to the regenerator is 80 to 90°C. In optimizing the refrigerant charge amount of the ejector refrigeration system, the refrigerant supplied from the regenerator was charged to a gaseous state, the flow rate of the refrigerant flowing through the ejector motif increased as the amount of refrigerant increased, and as the flow rate of the refrigerant flowing to the evaporator decreased, the COP was at most 1.1. In the case of charging the refrigerant to a liquid state, the COP was at most 1.5. Based on the results derived from the research on the ejector refrigeration system's performance factors, a study was performed on the system's operation and performance characteristics according to the heat recovery ejector refrigeration system's operating environment. According to the change of compressor capacity, the operation and performance characteristics according to the ejector nozzle size applied to the refrigeration system were analyzed. When the ejector nozzle size is smaller than the system capacity, the temperature and pressure of the refrigerant discharged due to a pressure drop in the nozzle were lower than the inlet pressure of the evaporator. Among the ejector nozzle sizes, the refrigeration capacity increase rate of the ejector with a nozzle size of 1.8 mm was the highest, and the COP was the highest with nozzle size 3.6 mm. Besides, when the system increasing the evaporator's capacity to utilize the waste heat, the state of the refrigerant supplied to the regenerator was in the form of liquid and gas. As results, in the regenerator system in which the state of the refrigerant is supplied to a liquid state, the temperature and pressure of the refrigerant discharged from the ejector increase as the flow rate increases, When the state of the refrigerant supplied from the heat recovery ejector refrigeration system to the regenerator was liquid, it was found that the supplying system had a 26% higher COP than the gaseous supply system. Based on the results of the heat recovery ejector refrigeration system, the system was applied to the refrigerated truck. The performance comparison with the vapor compression refrigeration system has been conducted under the same experimental conditions. The COP shows that 26% higher in the heat recovery ejector refrigeration system than the vapor compression system.