What Is an Ammonia Glycol Refrigeration System and How Does It Work

An ammonia glycol refrigeration system is a type of industrial refrigeration system that uses a mixture of ammonia and glycol as the refrigerant.

This system is commonly used in applications where a high-temperature difference is required, such as in cold storage warehouses and ice rinks.

The system works by using a compressor to compress the ammonia gas, which then transfers its heat to a condenser coil.

The ammonia gas is then cooled and liquefied, and the liquid is mixed with glycol to create a solution that can be pumped throughout the system.

This solution is then cooled further in an evaporator coil, where it absorbs heat from the surrounding air or product, causing the ammonia to evaporate and the glycol to remain in a liquid state.

In an ammonia glycol refrigeration system, the system design plays a crucial role in ensuring efficient operation and safety. The system can be designed in various configurations, including a cascade system, where multiple evaporators are connected in series to achieve the desired cooling temperature.

The system design must take into account the properties of the ammonia and glycol mixture, which has a boiling point of around -27°C. This allows for effective heat transfer and efficient operation of the system.

The system design also involves the selection of suitable components, such as compressors, pumps, and heat exchangers, which must be able to withstand the high pressures and temperatures involved in the process.

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The working principle of an ammonia glycol refrigeration system is quite fascinating. It involves several stages that work together to keep things cool.

The process begins with liquid ammonia flowing into the evaporator coil, where it absorbs heat from its surroundings and evaporates into gas. This process is called evaporation.

The gaseous ammonia then moves into a compressor, where its pressure and temperature increase significantly. This is a crucial step in the process.

The high-pressure hot gas flows into the condenser, where it releases its heat to the cooling medium and turns back into a liquid. This is called condensation.

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The high-pressure liquid ammonia then passes through an expansion valve, reducing its pressure and temperature before it returns to the evaporator. This process repeats continuously.

The glycol loop is separate from the ammonia loop but works in tandem with it. Glycol absorbs heat from the area that needs cooling and transfers this heat to the evaporator, where ammonia absorbs it.

Here's a quick rundown of the stages:

A chiller is essentially a refrigerator that includes a compressor, evaporator, condenser, and a metering device.

Chillers can be highly energy efficient, especially those using ammonia, which has no ozone depletion potential or global warming potential.

Ammonia chiller systems have a much better part-load efficiency and can be ready in design, efficiency, safety, and costs when environmental concerns become more important.

Standard screw compressors with variable-volume ratio regulation and capacity regulation down to 10 percent are often used in ammonia chiller systems.

Glycol is frequently used in heat transfer and cooling applications, providing better heat transfer parameters than water and can be mixed with water to provide a variety of heat transfer characteristics.

The reliability and durability of ammonia components provide for the lowest life cycle cost of any chiller over a 20-year cycle.

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