SPX Flow (http://www.spxflow.com/en/hankison/) has introduced a new range of energy-saving refrigerated air dryers by Hankison (named FLEX Series – see http://www.powderbulksolids.com/article/New-Compressed-Air-Drying-Technology-02-07-2017), which uses phase change materials in its heat transfer technology, to enable the removal of liquid from compressed air extremely efficiently.
The dryers have been designed with a 3-in-1 heat exchanger in which the PCM encapsulates the refrigeration and compressed air circuits. This allows the phase change material to stay colder for longer periods of time, cycling the refrigerant compressor less often than conventional energy saving designs.
Using PCM allows for more regulated temperature and fewer cycles, thus delivering greater energy savings. The PCM is chosen to melt and solidify above 0°C and does not require the use of glycol, pump, tank, or hot gas bypass, further increasing the efficiency of the dryer.
Work on the use of PCMs as an addition to refrigeration circuits is becoming well known and there are many patents on the subject as well as several practical applications. “Buffer storage” of heat (from the condenser) or cold (from the evaporator) are typical applications. SPX Flow have a patent application (WO2017018594 (A1)) on this development.