The difference between a cold dryer and a suction dryer

The main differences between the cold dryer and the suction dryer are reflected in the following aspects:

1. Working principle:
   • The cold dryer is based on the principle of refrigeration and dehumidification, and cools the saturated compressed air from the upstream to a certain dew point temperature through heat exchange with the refrigerant, condenses a large amount of liquid water, and is automatically discharged from the machine after separation by the gas-liquid separator, so as to achieve the purpose of water drying.
   • The suction dryer uses the principle of pressure swing adsorption to contact the desiccant under a certain pressure, and the vast majority of the moisture is adsorbed in the desiccant. The dry air enters the downstream to work, thereby achieving the purpose of deep drying.
2. Water removal effect:
   • The cold dryer is restricted by its principle and may freeze when the temperature is too low, so its dew point temperature is usually between 2~10℃.
   • The suction dryer does not need to be dried by temperature changes, and the desiccant used (such as alumina) can be deeply dried, so the dew point temperature at its outlet can usually reach below -20°C to achieve deep drying.
3. Energy loss:
   • The cold dryer needs to do work through refrigerant compression to achieve cooling, so the power supply will be relatively high.
   • The suction dryer mainly controls the valve through an electrical control box. Usually, the electric power is only about a few dozen watts, and the energy loss is relatively low.
4. Gas loss:
   • The cold dryer achieves the purpose of removing water by changing the temperature. The moisture is discharged through the automatic drainage machine, so there is no loss of gas.
   • The dryer needs to be regenerated after the desiccant absorbs water and is saturated, so there will be about 12% to 15% regeneration gas loss.
5. Fault rate:
   • The refrigerant system and air system of the cold dryer, including the electrical parts, are relatively complex, so the failure rate is relatively high.
   • The suction dryer has only components such as valves and ordinary solenoid valves, and its structure is relatively simple and the failure rate is usually low.

To sum up, there are obvious differences in the working principle, water removal effect, energy loss, gas loss and failure rate. Which device to choose depends on the specific application requirements and scenarios.