Applying storage-enhanced heat recovery room air-conditioner (SEHRAC) for domestic water heating in residential buildings in Hong Kong

Jie Jia, Wai Ling Lee

Research output: Journal article publicationJournal articleAcademic researchpeer-review

28 Citations (Scopus)


Storage-enhanced heat recovery room air-conditioner (SEHRAC) is considered one of the most effective measures to curb energy use in residential dwellings. However, little has been done on optimal design of the storage tank. For application in dense living environment like Hong Kong, another concern is whether or not the amount of recoverable heat can meet the household water heating demand. In this study, a typical residential estate in Hong Kong was chosen for supply and demand analysis. The analysis was based on hour-by-hour simulations using actual building characteristics and previously identified utilization patterns. It was found that with the use of SEHRAC, the daily cumulative recoverable heat far exceeds the daily household water heating demand. For optimal design of the storage tank, an air-conditioner model (REFMOD) was developed to enable ascertaining the operating parameters at the refrigerant side of SEHRAC. Other design requirements of the storage tank including the minimum required heat storage capacity and heat transfer effectiveness were determined. The potential energy and energy cost savings, as well as CO2emission reduction for wider application of SEHRAC were estimated as 9.3% of the overall contribution of the residential sector in Hong Kong.
Original languageEnglish
Pages (from-to)132-142
Number of pages11
JournalEnergy and Buildings
Publication statusPublished - 1 Jan 2014


  • Air-conditioner
  • Dense living environment
  • Free water heating
  • Heat recovery
  • Residential building
  • Storage tank design

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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