Expériences et modélisation pour la distribution transitoire de frigorigène et d'huile dans un système de chauffe-eau à pompe à chaleur résidentiel

Translated title of the contribution: Transient refrigerant and oil distribution in a residential heat pump water heater system: Experiments and model

Wenzhe Li, Pega Hrnjak

Research output: Contribution to journalArticlepeer-review

Abstract

This paper presents an experimental and numerical investigation of the transient refrigerant and oil distribution in a residential heat pump water heater (HPWH) system. In the experiments, R134a is paired with POE 22 oil. The quick closing valve technique (QCVT) is used to trap the refrigerant and oil in each section of the system. The trapped refrigerant mass is measured after recovered by liquid nitrogen. The retained oil mass in each section, except for the compressor, is determined by the mix and sample technique (MST). Five experiments are conducted to cover a full warm-up of five hours. The experimental data shows that most of the refrigerant is in the heat exchangers. During the water warm-up, the inventory of the refrigerant generally decreases in the evaporator, while in the condenser, it decreases in the first three hours and later increases. The measurements also indicate that most of the oil stays in the compressor and the escaped oil is mainly retained in the heat exchangers. Besides, a model is developed to predict the refrigerant and oil retention in the heat exchangers by applying the mixture vapor quality to calculate the void fraction. The developed model predicts the refrigerant inventory in the condenser with an average deviation of 7.4%, and in the evaporator, 9.1%. The average deviations in the predictions of the oil retention in the two heat exchangers are 15.8% and 10.2%.

Translated title of the contributionTransient refrigerant and oil distribution in a residential heat pump water heater system: Experiments and model
Original languageFrench
Pages (from-to)184-193
Number of pages10
JournalInternational Journal of Refrigeration
Volume129
DOIs
StatePublished - Sep 2021

Keywords

  • Heat pump water heater
  • Model
  • Refrigerant and oil
  • Transient distribution

ASJC Scopus subject areas

  • Building and Construction
  • Mechanical Engineering

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