Performance evaluation and strategies of subcooling control in residential heat pump systems

Bruno Yuji Kimura De Carvalho, Pega Hrnjak

Research output: Chapter in Book/Report/Conference proceedingConference contribution


In most residential heat pump systems, the refrigerant flow has been controlled with focus on preventing liquid intake at the compressor suction. The use of electronic expansion valves allows new control methods to be employed. One of the methods proposed is to control subcooling at the condenser outlet keeping the system at maximum efficiency or capacity. The paper presents an investigation based on ideal cycle analysis and experimental data of a residential heat pump system on the performance and possible subcooling control strategies. Subcooling control was able to improve performance by 8.6%, 7.4% and 5.9% for outdoor ambient temperature of, 0C, -5C and - 10C, respectively. A simple linear regression of the subcooling and discharge superheat based on the condensation and evaporation temperature difference can be used to achieve maximum efficiency. The use of discharge superheat to indirectly control subcooling provides an accurate and stable method of maximizing heating performance factor, but requires correction based on the refrigerant charge of the system.

Original languageEnglish (US)
Title of host publicationICR 2019 - 25th IIR International Congress of Refrigeration
EditorsVasile Minea
PublisherInternational Institute of Refrigeration
Number of pages8
ISBN (Electronic)9782362150357
StatePublished - 2019
Event25th IIR International Congress of Refrigeration, ICR 2019 - Montreal, Canada
Duration: Aug 24 2019Aug 30 2019

Publication series

NameRefrigeration Science and Technology
ISSN (Print)0151-1637


Conference25th IIR International Congress of Refrigeration, ICR 2019


  • Air Conditioning
  • Control (Generic)
  • Domestic Heat Pump
  • Electronic Expansion Valve
  • Optimization
  • Subcooling

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering
  • Mechanical Engineering
  • Condensed Matter Physics


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