Theoretical Analysis And Experimental Study On Defrosting Method Of CO₂Refrigeration System

According to the requirements of the national "1025" planning, plan to2015our country to make the total cold storage capacity doubled. The rapid growth of cold storage capacity on the one hand is convenient for people’s life, enrich the people dining table. On the other hand also brought heavy burden to the environment.In this case, people began to use CO2the environment-friendly refrigerant for refrigeration, due to the special refrigeration CO2the refrigerant, the traditional hot gas defrosting is difficult to achieve in CO2refrigeration system,In this paper,in view of the special system of CO2refrigeration system,puts forward a new application in the refrigeration system defrosting methods:thermal glycol defrosting.In the defrosting process of ethylene glycol solution through the exhaust gas heat exchanger and the compressor for heat exchange,make their own temperature higher. In the process of ethylene glycol as the compressor discharge of cooling, reduce the heat load of condenser.In the setting of glycol solution at constant temperature, different temperature were experimentally. The higher the temperature, the temperature difference between inlet and outlet of ethylene glycol solution is small, the defrosting time is short. Although the defrosting time than the hot gas defrosting time is long, but should not be used for carbon dioxide refrigeration system hot gas defrosting, defrosting method which is feasible.In the setting of cold storage temperature remains unchanged, the ethylene glycol solution with different temperature defrosting, that is not the glycol solution temperature is higher, the defrosting effect is better results, experimental results show, ethylene glycol solution temperature defrosting effect at15℃is better.In the article also introduces the mathematical model of numerical heat exchanger under frosting condition calculation method, and the defrosting conditions on the evaporator is the establishment of the mathematical model, solution and analysis process.The issue of solving the CO2refrigeration system defrosting process proposed new method using ethylene glycol solution, although this method still exists some individual problems, it needs to be further improved, but can be used for reference in the development process of frost thawing CO2refrigeration system and improvement.