The effects of improper refrigerant charge on the performance of a heat pump with an electronic expansion valve and capillary tube

J. M. Choi, Y. C. Kim

Research output: Contribution to journalArticle

84 Citations (Scopus)

Abstract

For inverter heat pumps and multi-type heat pumps, conventional expansion devices such as capillary tubes, short tube orifices, and thermostatic expansion valves (TXVs) are being gradually replaced with electronic expansion valves (EEVs) because of the increasing focus on comfort and energy conservation. In this study, the effects of off-design refrigerant charge on the performance of a water-to-water heat pump are investigated by varying refrigerant charge amount from - 20% to +20% of full charge in a steady state, cooling mode operation with expansion devices of capillary tube and EEV. The characteristics of the heat pump with an EEV are compared with those with a capillary tube. The capillary tube system is more sensitive to off-design charge as compared with the EEV system. Cooling capacity and COP of the EEV system show little dependence on refrigerant charge, while those are strongly dependent on outdoor conditions. In general, for a wide range of operating conditions the EEV system shows much higher performance as compared with the capillary tube system. The performance of the EEV system can be optimized by adjusting the EEV opening to maintain a constant superheat at all test conditions.

Original languageEnglish
Pages (from-to)391-404
Number of pages14
JournalEnergy
Volume27
Issue number4
DOIs
Publication statusPublished - 2002

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Pollution
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering

Fingerprint Dive into the research topics of 'The effects of improper refrigerant charge on the performance of a heat pump with an electronic expansion valve and capillary tube'. Together they form a unique fingerprint.

  • Cite this