How Do Ammonia Evaporator Works?

An ammonia evaporator is a refrigeration unit based on a compression cycle, the working principle of which can be summarised in the following steps:

Compression: The compressor in an ammonia evaporator compresses the ammonia gas from a low pressure state to a high pressure state. This process consumes energy and is usually powered by an electric motor.

Condensation: The high pressure ammonia gas enters the condenser and comes into contact with outside air or a cooling medium, thus lowering the temperature. During condensation, heat is released from the ammonia gas, which cools it and transforms it into a liquid state.

Expansion: The condensed liquid ammonia enters the evaporator through an expansion valve (throttling device). Under the action of the expansion valve, the pressure of the liquid ammonia suddenly decreases, thus causing rapid evaporation. This process absorbs heat from the surrounding environment, causing the ammonia to revert to a gaseous state.

Evaporation: Gaseous ammonia enters the evaporator and comes into contact with the air or object to be cooled. During the evaporation process, the ammonia absorbs heat from the surroundings, which causes the temperature of the air or object to drop.

Circulation: The ammonia gas enters the compressor again to start a new cycle. By continually cycling through the processes of compression, condensation, expansion, and evaporation, ammonia evaporators are able to provide a continuous cooling effect.

In summary, ammonia evaporators utilise the phase change properties of ammonia gas at different pressures to achieve a cooling effect by absorbing heat from the air or object to be cooled and discharging it to the external environment through the compression cycle. This principle of refrigeration is used in many applications including industrial refrigeration, commercial cold storage, pharmaceutical and chemical.