Study On The Construction And Characteristics Of Ejection Refrigeration System For Marine Air-conditioning

In the marine air-conditioning system driven by waste heat,the temperature and humidity can be decoupled by using the rotary dehumidification.The ejection refrigeration system as the cooling source of the air-conditioning system can only bear the sensible heat load of the system,and the evaporation temperature of the ejection refrigeration system can be improved to improve the performance of the system.Ejection refrigeration system recovers waste heat from ships as the generating heat of the system.Aiming at the ejection refrigeration system driven by waste heat for marine air conditioning,the suitable refrigerant is synthetically analyzed and selected.The components of ejection refrigeration system are designed and selected.An experimental platform of ejection refrigeration system for marine air conditioning was built based on modular design concept.The experimental study on the characteristics of the system is carried out by using the experimental platform.Firstly,the basic physical properties,ejection coefficient,COP value and charge of five environmentally friendly refrigerants are analyzed by using Eames model.The system performance of R718 refrigerant at high temperature was analyzed and R718 was selected as the working fluid of the ejection refrigeration system.Secondly,according to the physical properties of R718 and the design parameters of marine air conditioning and ship waste heat,the structure of steam ejection in the system is calculated and analyzed,and the evaporator,condenser,liquid storage and other components are selected and designed.Then,according to the results of type selection design,a three-dimensional visualization model of the overall layout of the experimental platform is built with modularization design concept.On the basis of the visual model,a series of measuring and adjusting control instruments are selected according to the experimental requirements,and a data acquisition system is built.Then the system pipeline layout is optimized.After the completion of the platform,the airtight performance of the experimental research platform is obtained by pressure-holding test,and technical means are adopted to improve the system airtight to meet the experimental requirements,and the experimental research platform is completed.Finally,through a number of experimental tests,we choose the ejector structure with better performance to study the characteristics of the system performance varying with thecondensation temperature,evaporation temperature and temperature.In order to tap the potential of the system,we choose a specific ejector structure to study the lowest evaporation temperature of the system under the conditions of ensuring the normal operation of the system and realizable in the laboratory.The experimental results show that:(1)The COP value of the ejection refrigeration system can be significantly increased by increasing the evaporation temperature of the system.(2)There is a maximum condensation temperature(pressure)in the system,which makes the COP value of the system maintain the maximum under the corresponding conditions.When the condensation temperature(pressure)exceeds the maximum value,the COP value of the system decreases sharply.(3)When the structure parameters of the ejector are fixed,the COP value of the system in the critical working state will decrease with the increase of the occurrence temperature,but the critical condensation temperature will rise.The proper increase of the occurrence temperature of the system is beneficial to the normal operation of the marine ejector refrigeration system at higher condensation temperature.