Identification and Emission of Non condensable Gases in Cold Storage Systems | Air Mixing, Abnormal Condensation Pressure, and Air Release Operations
The refrigeration system can only have refrigerant and refrigeration oil inside, mixed with non condensable gases such as air and nitrogen, which will increase the condensation pressure, increase the power consumption of the compressor under the same load, and raise the exhaust temperature.
Simple identification of non condensable gases: Stop the machine and let it stand. After the system temperature is balanced, compare it with the refrigerant saturation pressure temperature comparison table. If the measured pressure is higher than the saturation pressure corresponding to that temperature, it indicates the presence of non condensable gases.
Non condensable gases mainly accumulate at the top of the condenser, and the vent port is set at the highest position of the condenser; Do not place refrigerant randomly from the maintenance valve or fluorine inlet, as it may release refrigerant easily.
The condenser of the Xitelide water-cooled and air-cooled unit is equipped with a reserved air release interface, which is suitable for long-term operation of low-temperature cold storage. The energy consumption increases significantly when air is mixed into the tropical high-temperature environment.
Common channels for air to enter the system include: inadequate evacuation, slight leakage in the pipeline under negative pressure, prolonged opening of the maintenance cover, and failure to empty the pipeline when adding refrigerant.
Many maintenance technicians see high pressure and directly release refrigerant to reduce pressure, without releasing air. The more pressure is released, the more abnormal it becomes, resulting in refrigerant waste.
The air release operation should be carried out when the unit is running stably and the condenser temperature is stable. Slowly open the valve slightly and discharge intermittently; Opening it up at once results in significant loss due to the large amount of refrigerant spraying out.
The POE oil system is mixed with air, and the oxygen and moisture in the air accelerate the hydrolysis and acidification of the oil, which not only leads to high pressure, but also causes corrosion and ice blockage chain failures.
Cold storage under negative pressure conditions (evaporation pressure lower than atmospheric pressure) will continue to suck in air if there is a slight leak in the pipeline. This type of system requires higher leak detection standards to prevent leakage on the negative pressure side.
In high temperature environments for foreign trade projects, it is easy for customers to attribute high pressure solely to the presence of refrigerant. Therefore, it is necessary to label the saturation pressure comparison method in the technical documentation to distinguish between excessive refrigerant and mixed air.
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FAQ
How to determine if the system has air mixed in? After settling, the pressure is higher than the saturation pressure of the refrigerant.
Where do non condensable gases accumulate? Top position of condenser.
3. Where should the air be released from? The highest point of the condenser is the air outlet.
4. High pressure and high energy cannot directly release refrigerant? If it is air, releasing refrigerant cannot solve the problem.
5. What are the consequences of a slight leak in the negative pressure side pipeline? Continuously inhaling air and producing non condensable gases.
What are the hazards of air entering the system besides high pressure? Accelerate POE oleic acid corrosion.
How to operate the valve when releasing air? Slowly open and intermittently discharge.
