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Novel rotary pressure exchanger for highly efficient trans-critical CO2 refrigeration cycle.

Number: 0056

Author(s) : THATTE A., FRICKE B., NAWAZ K.

Summary

A new device called the Trans-critical Rotary Pressure Exchanger (TCPX) is developed for direct fluid-to-fluid pressure exchange, and application of this novel device in a trans-critical CO2 refrigeration cycle is demonstrated. A TCPX placed between the gas cooler and receiver serves simultaneously as a parallel compressor that does not require external mechanical or electrical energy and as an expansion device. TCPX utilizes high pressure, high density supercritical CO2 (sCO2) from the gas cooler exit to compress the lower pressure CO2 vapor from receiver to the highest pressure in the system. Simultaneously, it expands high pressure sCO2 to the lower receiver pressure, thus creating a two-phase, cold fluid stream ready for heat absorption in the evaporator. Energy, entropy and exergy analysis of the TCPX integrated cycle is conducted, highlighting thermodynamic advantage provided by TCPX. Additionally, results from a 3D multi-phase flow and species transport model of TCPX are presented, which shed light onto the gas dynamics of compression and expansion waves taking place inside TCPX. These compression waves produce the temperature rise inside TCPX needed for heat rejection in the gas cooler, while the expansion waves produce the cooling and phase change from supercritical state to liquid-gas two phase equilbrium needed for heat absorption in the evaporator, simultaneously during one rotation of the TCPX rotor. Coefficient of performance (COP) improvement of up to 20% due to TCPX is demonstrated experimentally in a 100 kW scale standard booster refrigeration system. System controls methodology for TCPX integrated system to achieve required optimal gas cooler and receiver pressure control is demonstrated. Furthermore, it is shown that significantly higher efficiency gains (greater than 40% COP improvement) and associated energy savings can be obtained through design of a TCPX-centric refrigeration architecture.

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Pages: 12 p.

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Details

  • Original title: Novel rotary pressure exchanger for highly efficient trans-critical CO2 refrigeration cycle.
  • Record ID : 30029683
  • Languages: English
  • Subject: Technology
  • Source: 15th IIR-Gustav Lorentzen Conference on Natural Refrigerants (GL2022). Proceedings. Trondheim, Norway, June 13-15th 2022.
  • Publication date: 2022/06/13
  • DOI: http://dx.doi.org/10.18462/iir.gl2022.0056
  • Document available for consultation in the library of the IIR headquarters only.

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