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Novel Pressure-Exchange Ejector Superior to Current Compressors

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Charles A. Garris
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Jerry Comanescu
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Patent Protection

Pressure Exchanging Ejector and Methods of Use

US Patent 6,138,456

Pressure Exchanging Compressor-Expander and Methods of Use

US Patent 6,434,943

Pressure Exchange Ejector

US Patent 7,497,666

There are three basic refrigeration cycles that are suitable for domestic, commercial, and vehicular air conditioning: reverse Rankine cycle, absorption cycle, and ejector refrigeration. The most common conventional technology uses the reverse Rankine cycle, which provides excellent refrigeration but at a substantial cost because it is powered directly by mechanical energy taken from an electric motor. The advantages of ejector refrigeration systems are that they are very simple and have a low capital cost. The main disadvantage of conventional ejector refrigeration systems, however, is that they suffer from a low coefficient of performance (COP).  The physical mechanism by which conventional steady-flow ejectors operate is the turbulent entrainment between the primary (driving) flow and the secondary (driven) flow, which is highly dissipative and causes the  low COP. 

GW researchers have developed an environmentally friendly refrigeration system containing a novel ejector. The idea is that there is a mechanism for direct flow induction, other than turbulent mixing, that does not rely on highly dissipative turbulent mixing, but rather on the thermodynamically reversible work of interface pressure forces through a mechanism known as pressure exchange (PE).  PE relies on the work done by pressure forces exerted by an expanding energetic fluid on a compressed, less energetic fluid across the interface between them. PE offers a non-dissipative flow induction process that is highly efficient, extremely compact, and low in capital cost. With a reduction in turbulent mixing, the COP of ejector systems is comparable to commercially available absorption cycle systems.

Researchers have patented various designs for this novel pressure exchange ejector and continue to perfect their design. This novel PE ejector boosts efficiency and the PE-ejector-refrigeration system aims to replace commercially used vapor-compressor refrigeration units.


  • Refrigeration
  • Air Conditioning


  • More efficient than conventional ejectors