RNR/ Exal manufactures some of the largest Chilled Water Air/Gas Dryers globally for Compressed Air / Gas. The Chilled Water dryer is similar to a refrigerated dryer but uses chilled water for cooling Compressed Air/ Gas instead of a refrigerant.

Compressed Air/Gas enters the dryer through a Gas to Gas heat exchanger. The incoming Gas/ Air is pre-cooled using the outgoing dry Gas/ Air. This economizer heat exchanger can enable a reduction in cooling heat-load 10- 40% or more depending on the working pressure and compressor discharge temperature etc.

The pre-cooled Gas / Air then is cooled using a chilled water. In the process of cooling, the moisture in the Gas / Air condenses. The pressure dewpoint achieved is around 10^oC. The limitation here is the chilled water temperature. A dewpoint of Chilled water temperature +2^oC can be achieved. For dewpoints as low as 3^oC, client can provide chilled glycol or equivalent mixtures which operate at lower temperatures (At pressure dewpoints less than 3^oC moisture starts forming ice and can lead to heat exchanger failure even under high pressure.)

NOTE: The chilled water dryer is primarily used at plants where there are chillers with excess chilled water Tonnage of Refrigeration. Typically, branded flooded screw / centrifugal chillers (Carrier, Diakin, Trane etc.) have very low KW/ TR (approximately 0.5 to 0.6 KW/TR.) The chilled water dryer is a highly economical solution vs a refrigerated dryer (in both CAPEX + OPEX) in case the application can tolerate a higher pressure dewpoint. A point to be noted here is that the chilled water dryer is dependent on the chiller for performance. A refrigerated dryer is its own individual isolated system. In case of chilled water dryer an issue of chiller(s) will result in all dryers in connection not performing. There is also the possibility of compressed air entering a central chilled water line. This dryer must be made robust.

RNR/ Exal Chilled Water Dryers can be designed for blowers and compressors. This includes working pressure as low as 0.5 Bar(g) and up to 70 Bar(g).

All our systems are designed based on proper heat load calculations coupled with simulation based evaluation of each heat exchanger to determine pressure drop and heat transfer area effectiveness. For the heat-load we take into account the Kg/Hour of Compressed Gas/ Air and Moisture entering the system. In addition, we consider the moisture quantity at the inlet of dryer based on compressor inter-stages, compressor suction etc. The cooling required to condense the moisture to the desired dewpoint is based on the Chilled Water to Air/ Gas heat-load and the pre-cooler effectiveness.

* RNR / Exal has the lowest committed and delivered pressure drops in the industry. Our systems have been designed for very low-pressure applications such as use with blowers where working pressure is 0.5 Bar(g) and pressure drop is critical.