Preliminary Study of a Novel R718 Compression Refrigeration Cycle Using a Three-Port Condensing Wave Rotor

Abstract

Using a novel 3-port condensing wave rotor enhancing the turbocompression in a R718 refrigeration cycle, which uses only water as a refrigerant, has been introduced. The wave-rotor implementation can increase efficiency and reduce size and cost of R718 units. The condensing wave rotor employs pressurized water to pressurize, desuperheat, and condense the refrigerant vapor—all in one dynamic process. The underlying phenomena of flash evaporation, shock wave compression, desuperheating, and condensation inside the wave rotor channels are described in a wave and phase-change diagram. The thermodynamic process is shown in pressure–enthalpy and temperature–entropy diagrams. A computer program based on a thermodynamic model was generated to evaluate the performance of R718 baseline and wave-rotor-enhanced cycles. The effect of some key parameters on the performance enhancement is demonstrated as an aid for optimization. A performance map summarizes the findings. It shows optimum wave rotor pressure ratio and maximum relative performance improvement of R718 cycles by using the 3-port condensing wave rotor.

Wave Rotor Research Program at Michigan State University

“…Vapor (2) High Pressure Water Using a 3-port condensing wave rotor in a water refrigeration cycle can also enhance the performance of R718 units by increasing the coefficient of performance (COP). This has been theoretically shown by Kharazi et al [52][53][54][55][56] using a thermodynamic cycle analysis which compares COP of a baseline cycle and a 3-port condensing wave rotor cycle. The authors have developed performance maps for specifying the maximum percentage increase in COP relative to baseline (COP gain ) obtained by the optimum choice of PR W = p 3 /p 2 for a given evaporator temperature (T 1 ) and a temperature lift (T 3 -T 1 ).…”

Characteristics of water vapor turbocompressors applied in refrigeration and heat pump systems

“…Development of axial turbocompressor for commercial chillers with water as refrigerant by Danish Technological Institute is presented by Madsboll (2011). Implementation of three port condensing wave rotor in R718 centrifugal compressor refrigerating cycle is given by Kharazi et al (2005Kharazi et al ( , 2006. A comparative analysis of the characteristics of water refrigerating systems and high temperature heat pumps is presented by Chamoun et al (2011).…”

Performance experiments with a gas wave ejector equipped with curved channels and an analysis of the influence of channel angles

“…Kenteld et al 20 of Imperial College London accomplished the rst test of this technology in conjunction with a gas-wave divider, 21 proving that these two three-port wave rotor devices can achieve equivalent efficiency to turbomachinery when the pressures at each port are close enough. Kharazi et al 22,23 of Michigan State University proposed the application of this technology to the R718 refrigeration cycle, using liquid water to eject and compress water vapor for condensation, instead of using a condenser and rst-stage compressor. This can help to reduce the overall structure size and the manufacturing and operating costs of this system by nearly 50%.…”