Inherent operational characteristics aided fuzzy logic controller for a variable speed direct expansion air conditioning system for simultaneous indoor air temperature and humidity control

Huaxia Yan, Yudong Xia, Xiangguo Xu, Shiming Deng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

21 Citations (Scopus)


In small to medium sized buildings, direct expansion (DX) A/C systems are extensively used. Multi-variable controllers (MVCs) have been developed for variable speed (VS) DX A/C systems to control indoor air temperature and humidity simultaneously. Based on the previous extensive research work on the inherent operational characteristics of DX A/C systems, an alternative simpler approach was applied, by developing a fuzzy logic controller (FLC) for simultaneous indoor air temperature and humidity control, using a VS DX A/C system. In this paper, the developments of the FLC are presented. Firstly, a detailed description of the algorithm for the FLC is given. This is followed by detailing an experimental VS DX A/C system where the FLC was tested. Finally, the results of controllability tests for the FLC are reported. Controllability tests results demonstrated that the FLC developed can achieve the simultaneous control over indoor air temperature and humidity, with a reasonable control accuracy and sensitivity.
Original languageEnglish
Pages (from-to)558-568
Number of pages11
JournalEnergy and Buildings
Publication statusPublished - 1 Jan 2018


  • Direct expansion air conditioning
  • Fuzzy logic control
  • Humidity control
  • Inherent operational characteristics

ASJC Scopus subject areas

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

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