The Function of a Refrigerated Dryer in an Air Compression System

A refrigerated dryer is an essential part of a completed Air Compressor system that removes moisture from compressed air by cooling it down to a low temperature. Moisture in compressed air can cause corrosion, contamination, and damage to pneumatic tools and equipment, as well as affect the quality of the final product. Therefore, it is important to dry the compressed air before using it in various applications.

A refrigerated dryer consists of two main components: a refrigeration circuit and a compressed air circuit. The refrigeration circuit uses a refrigerant (such as Freon) to cool down the compressed air. The refrigerant is compressed by a refrigeration compressor and then condensed by a condenser, where it releases heat to the ambient air. The liquid refrigerant then passes through an expansion valve, where it lowers its pressure and temperature. The cold refrigerant then enters an air-to-refrigerant heat exchanger where it absorbs heat from the hot compressed air and evaporates.

The compressed air circuit consists of an inlet filter, an air-to-air heat exchanger, an air-to-refrigerant heat exchanger, a moisture separator, and an outlet filter. The inlet filter removes dust and dirt from the incoming compressed air. The air-to-air heat exchanger pre-cools the compressed air by exchanging heat with the outgoing dry air. This reduces the load on the refrigeration system and improves its efficiency. The pre-cooled compressed air then enters the air-to-refrigerant heat exchanger, where it is further cooled down to about 38^oF (3.33^oC)by the cold refrigerant. At this temperature, most of the water vapor in the compressed air condenses into liquid water, which is then separated by a moisture separator and drained away. The dry compressed air then passes through the outlet filter, which removes any remaining particles or oil droplets. The dry compressed air then returns to the air-to-air heat exchanger where it is reheated by the incoming wet air. This prevents condensation from forming on the outside of the pipes and reduces the relative humidity of the dry air.

The function of a refrigerated dryer is to produce dry compressed air with a low dew point, which is the temperature at which water vapor starts to condense into liquid water. The lower the dew point, the drier the compressed air. A typical dew point for a refrigerated dryer is 37°F, which means that no water will condense in the compressed air unless its temperature drops below 37^oF. This dew point is suitable for most industrial applications that do not require very dry or high-quality compressed air.

A refrigerated dryer is one of the most common and economical methods of drying compressed air. It has several advantages, such as simple operation, low maintenance, high reliability, and low energy consumption. However, it also has some limitations, such as a limited dew point range, sensitivity to ambient temperature changes, and the potential environmental impact of refrigerant leakage. Therefore, it is important to select the right type and size of the refrigerated dryer for each specific application and to follow proper installation and operation guidelines.