Experimental Reasearch On Refrigeration Performance Of Quick Freezer

The refrigerator is a refrigeration equipment to maintain a constant low temperature,is also a kind of civilian products to make food or other items to keep constant low temperature,has been widely applied in modern life.With the rapid development of the world economy,the pace of people's life has been accelerating,and the living standard has been improved,so the demand for fresh food is increasing.In order to ensure food nutrition when the food is rapid cooling,food freezers rapidly became widely used.The experiment of quick freezer's refrigeration system is carried out to study it's cooling curve and refrigeration performance.The experiment results show that: when the refrigeration system of the quick freezer begins to cool down,the evaporation temperature is dropped immediately to be close to the lowest evaporation temperature and the evaporator's inlet temperature has a difference with water's temperature about 25?;the lowest evaporation temperature leads to the smaller mass flow rate of refrigerant entering the compressor,and compressor's power accounts for only about 60% of the rated power;the exergy loss is about 50% in the evaporator,thus to make the evaporation temperature match with the indoor temperature of quick freezer is an important means to increase the freezer's cooling spend sharply.In order to reduce the rapid freezer cooling time,and improve the refrigeration performance,in this paper,the method of improving the evaporation pressure,increasing the evaporation temperature and decreasing the superheat degree of the evaporator outlet are put forward.The thermal expansion valve is connected with the electronic expansion valve and the hand valve to regulate the flow rate,but the flow rate increases,the pressure drop of the evaporator is increased,and the outlet temperature of the evaporator is lower than the inlet temperature of the evaporator.Therefore,the method of changing the evaporator pipeline structure to reduce the pressure drop of the evaporator is proposed.When the 3 section of the evaporator tube is connected in parallel to the 6 section,the pressure drop of the evaporator is reduced by 40%,then go on the experiment after transform.Due to rapid freezing cooling time mainly occurred in the transition period,thus control the evaporation pressure is feasible.When the evaporation pressure is 2.0bar,the rapid cooling refrigerator is the fastest,reduce the time of about 20%.In addition for the cooling performance of transition period,to maintain the original performance of rapid freezer.To ensure fast freezer cooling time under the conditions of this new scheme of throttling,called a new method of throttling adapting to the low temperature freezing cabinet,which comprises two capillary tube and a solenoid valve.The throttle pressure drop of refrigerant is controlled by the switch of the electromagnetic valve.The evaporation pressure to achieve two pressure adjustment,realize the freezer single-stage refrigeration cycle cooling system,and can simplify the system.