Refrigerant Vapour Compressor

The Refrigerant Vapour Compressor employed in refrigeration equipment is to change
drastically due to concerns over ozone layer depletion and global warming potential of
refrigerants. The international legislation, after the Vienna Convention and Montreal Protocol,
banned CFCs by 2010 followed by a blanket ban of HCFCs by 2030.
The new refrigerants with zero ODP and low GWP require higher operating pressures that due
to low flow rates are challenging for refrigerant vapour compressors. The higher pressure
requirement is also better suited to oil free operation. Conventionally, the sub 200 kW units
are oil lubricated, positive displacement machines (scroll and screw) that are becoming
redundant due to the high pressure requirements. Oil-free turbocompressors, regularly
employed for >200 kW industrial units are not suitable for sub-200 kW units due to low flow
rates.
Dynamic Boosting Systems Ltd (DBS) has developed and patented an innovative low specific
speed turbocompressor with high efficiency, TurboClaw®, suited to low flow rates and
multistage applications (due to its short axial length). The design is already well-proven for
compressing air applications (electrically driven superchargers). TurboClaw® has a simple
design, amenable to low cost manufacture which translates to commercial viability.
For mid-range, light industrial refrigerant applications of 16USRT (US Refrigerant Tons),
equivalent to 56 kW of heat removal – the target for the present proof of concept proposal – a
two stage TurboClaw® at 50,000 rpm delivers the same performance as a three stage
centrifugal compressor at 125,000 rpm. The proposed project aims to prove the suitability of
TurboClaw® for this application. A 12 month project has been planned.
The technology can also be used in a multitude of other plants requiring refrigerant vapour
compressors (e.g. petrochemical) as well as energy recovery from waste heat (organic Rankin
cycle).