Dynamic evaluation of circulation composition of zeotropic refrigerant in heat pump system with NIR absorption spectroscopy.

Number: 2371

Author(s) : MIYAWAKI K., SHIKAZONO N.

Summary

Composition shift evaluation and analysis of difluoromethane (R32) and 2,3,3,3-tetrafluoropropene (R1234yf) mixture were experimentally conducted using near-infrared absorption (NIR) spectroscopy in a heat pump system with a pseudo accumulator. The NIR spectroscopy is a non-destructive direct detection method validated for the zeotropic mixture in our previous works (Miyawaki et al., 2023, Miyawaki and Shikazono, 2023). Molar attenuation coefficients at wavelengths of 1.59, 1.64, 1.70 and 1.78μm were obtained using 1.5 μm wavelength data as a reference spectrum, where the errors were calibrated by a Gaussian process regression in this work. The heat pump system was charged with refrigerants of R32 : R1234yf = 27 : 73 and 52 : 48 wt%, and increase in the volatile R32 component were detected when large retention was observed in the visualized accumulator. The correlation between the retention ratio to charged refrigerant and circulating composition measured in steady conditions showed good agreement with the analytical estimation based on the chemical properties of the components. However, the dynamic composition was dependent not only on the chemical properties but also on the refrigerant transition in the heat pump system. The transient temperature and pressure information of the accumulator circuit were identified as key parameters for improving dynamic detection of composition shift, as they have a qualitative impact on refrigerant retention in the accumulator and thus dominate the circulating composition.

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  • Original title: Dynamic evaluation of circulation composition of zeotropic refrigerant in heat pump system with NIR absorption spectroscopy.
  • Record ID : 30033158
  • Languages: English
  • Subject: Technology
  • Source: 2024 Purdue Conferences. 20th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2024/07/17

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