How does a cold storage evaporator work to maintain low temperatures inside the storage facility?

A cold storage evaporator works based on the principles of refrigeration to maintain low temperatures inside the storage facility. The primary function of the evaporator is to absorb heat from the interior of the cold storage and transfer it to the refrigerant circulating within the system. Here's how the process works:

Circulation of Refrigerant: A closed-loop refrigeration system contains a refrigerant, typically a gas or a liquid, which has a low boiling point. The refrigerant circulates through the system, changing states from a low-pressure liquid to a low-pressure vapor as it absorbs heat.

Heat Absorption: Inside the cold storage, the evaporator coil is a network of tubes that contains the refrigerant. When warm air from the storage space comes into contact with the cold surface of the evaporator coil, the refrigerant absorbs the heat from the air.

Phase Change: As the heat is absorbed, the refrigerant undergoes a phase change from a low-pressure liquid to a low-pressure vapor. This change of state allows the refrigerant to take in more heat without a significant increase in temperature.

Circulation of Cooled Air: The cold refrigerant vapor inside the evaporator now circulates through the refrigeration system, carrying the absorbed heat away from the cold storage area.

Compressor and Condenser: The refrigerant vapor, now carrying the absorbed heat, enters the compressor, where it is compressed and converted into a high-pressure, high-temperature gas. This process increases the energy of the refrigerant and prepares it for the next step.

Heat Rejection: The high-pressure, high-temperature refrigerant gas flows to the condenser, where it releases the absorbed heat to the surrounding environment. The refrigerant condenses back into a high-pressure liquid during this heat-rejection process.

Expansion Valve: The high-pressure liquid refrigerant then passes through an expansion valve, where it undergoes a pressure drop. This reduces the refrigerant's pressure and temperature, converting it back into a low-pressure liquid. It is now ready to enter the evaporator again, continuing the refrigeration cycle.

By continuously cycling the refrigerant through this process, the cold storage evaporator effectively removes heat from the storage area, maintaining low temperatures and creating the ideal environment for preserving perishable goods. The efficiency of this process ensures that the cold storage remains at the desired temperature while minimizing energy consumption.