For the cold storage system, a shell and tube heat exchanger, a set of circulating pump unit and a set of water supply and constant pressure device are designed in the refrigeration plant room.Through shell and tube heat exchanger and fluorine in the direct refrigeration system for heat exchange, through the circulation pump group of continuous pressure transmission, so that the cold storage special coolant in the system continuous circulation. The specific workflow of the system is：The LM-4 Glacier Coolant in the system exchanges heat with low-temperature fluorine in the plate heat exchanger, reduce the temperature of the special coolant for the cold storage, and then through the pump unit of the special coolant system for the cold storage, the LM-4 coolant reaching – 30 ℃ is sent to the cold storage for heat exchange , absorb the heat of the cooled goods in the cold storage and maintain the storage temperature at – 18 ℃, The temperature of the coolant increases to -25℃ after absorbing the heat,and returns to the shell and tube heat exchanger in the refrigeration plant room through the pipeline for heat exchange, and the low temperature fluorine is cooled again.
Through the continuous circulation of the coolant solution in the system, the heat is brought back to the refrigeration plant room, and the heat is discharged outdoors through the phase change heat exchange of Freon. The temperature in the cold storage is to maintain the temperature required by the goods, so as to achieve the best environment for preserving the goods.
According to the actual situation of the old cold storage, the system fully considers the specific historical conditions and the existing operation status of the cold storage.The scheme of replacing only the refrigerating machine, the main pipeline of the system and the medium flowing in the pipeline without changing the enclosure structure and pipe arrangement of the existing cold storage .According to the requirements of the scheme, the main pipeline from the cold storage to the the refrigeration plant room is rearranged, and the newly arranged main pipeline is connected with the evaporator in the cold storage to form a closed loop of the coolant system. Change the transmission medium in the system from ammonia to LM-4 Glacier Coolant.
After the transformation, the system operates well. Through data observation, the refrigeration system of the cold row pipe cold storage fully meets the temperature requirements of the goods in the cold storage, but the temperature of the two cooling fans cold storage can only be maintained at -12℃. At present, these two cold storage are mainly used as ice storage.The specific reason is that the clooant of the heat exchange efficiency of the cooling fan is lower than that of the pipe, so it is necessary to appropriately increase the end heat exchange equipment and meet the requirements. Therefore, the practical application of refrigeration system conversion cooling system is feasible.According to the actual operation of special coolant for Glacier Coolant, the advantages of using coolant are summarized as follows:The direct refrigerant system is gathered in the refrigeration plant room, facilitating the manufacturing, installation, operation and management of overall system ,and improves the refrigeration efficiency.Reduce the refrigerant charge in the direct refrigeration system, reduce the pipeline layout area of the direct refrigeration system and reduce the leakage coefficient.The use of coolant system can facilitate the transmission of cooling capacity and the distribution and control of cooling capacity.The temperature control in the cold storage is more accurate, the temperature fluctuation is small, and the refrigeration quality of food is improved.
The new special coolant for cold storage has more advantages and application cases, and has better application prospects.