Disadvantages of Selecting Refrigerated Air Dryers as Water Removal Equipment for Air Compressors

Refrigerated air dryers are widely adopted in many scenarios. Whether considering environmental protection or the dryness of compressed air for industrial production, 

refrigerated air dryers play an important role and have been extensively applied in manufacturing enterprises. Nevertheless, numerous defects of refrigerated air dryers have gradually emerged. 

This article discusses the disadvantages of refrigerated air dryers. It is recommended to closely monitor unit operation during use, take preventive maintenance before faults occur, 

extend the service life of refrigerated air dryers and reduce enterprise operating costs.

Refrigerated Air Dryers

Refrigerated air dryers are sensitive to ambient temperature during operation. Generally, they cannot run efficiently when the temperature exceeds 38°C or drops below 0°C. 

In addition, large-capacity refrigerated air dryers consume massive volumes of cooling water, limiting their application in water-scarce regions. Especially for long-term operation under rated load, 

an automatic unloading device for the refrigerant compressor shall be equipped; otherwise, adverse impacts will be imposed on the refrigerant system.

As refrigerated air dryers adopt refrigeration technology, the refrigerant evaporation temperature must not fall below 2°C. Otherwise, ice will form and block pipelines, preventing compressed air from passing through.

Although refrigerated air dryers can achieve 100% effective air supply, restricted by their working principle, the minimum achievable pressure dew point of supplied air is approximately 3°C. 

Its performance is greatly affected by inlet air temperature: every 5°C rise in inlet temperature reduces the refrigeration efficiency by 30% and significantly elevates the air supply dew point. 

Ambient temperature also imposes substantial influence. Moreover, the refrigeration principle determines that the actual outlet pressure dew point cannot reach the set value of the evaporator. Therefore, 

to obtain a lower dew point, the power of the refrigerant compressor must be increased, which greatly raises production costs. Meanwhile, 

gases generated by refrigerants (Freon) damage the atmospheric layer and cause severe environmental pollution.

When the compressed air outlet temperature is 45°C and pressure dew point is 10°C, the energy consumption (mainly electric power) is approximately 6%. Despite the high market penetration of refrigerated air dryers, 

most brands are manufactured by small-scale workshops without leading high-end brands. This situation results from outdated refrigerated dryer technology, low manufacturing standards and non-standard market requirements.

Surveys show that most industries and pneumatic equipment require compressed air with a pressure dew point ranging from -20°C to -40°C. 

However, the measured dew point for most end users currently stands between 20°C and 35°C, accompanied by abundant liquid water. This drastically shortens equipment service life and increases failure rates.

In summary, the disadvantages of refrigerated air dryers are summarized as follows:
Restricted by technical principles, the compressed air quality fails to meet certain production requirements.
Unstable outlet air quality with liquid water present; the pressure dew point generally ranges from 2°C to 10°C.
Refrigerants (Freon) are used for cooling, causing serious atmospheric pollution.
Continuous operation of the refrigerant compressor leads to around 6% energy consumption when the pressure dew point reaches +10°C.