Performance study of thermostatic and electronic expansion valves of a water-cooled scroll chiller

Jayaprakash Saththasivam, Kim Choon NG

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Electronic expansion valves are progressively substituting conventional expansion devices such as capillary tubes and thermostatic expansion valves. Despite of higher initial cost, electronic expansion valve offers greater benefits that include wide range of capacity coverage, precise superheat control and optimum refrigerant flow rate. In this paper, the performance characteristics for both thermostatic and electronic expansion valve were evaluated. An externally equalized thermostatic expansion valve and a pulse width modulating electronic expansion were installed in parallel on a 15.5 kW water cooled scroll chiller. The performance ratings of the expansion valves were investigated at various set points that cover a wide range of operating conditions. A total of 27 different operating steady state set points were studied by manipulating the leaving chilled water temperatures, Tout,evap (6.7°C, 8.0°C, and 9.5°C), entering cooling water temperatures, Tin,cond (28°C, 29.4°C, and 31.0°C) and the compressor frequencies (50 Hz, 42.5 Hz and 35 Hz). The required water temperatures were achieved using mixing chambers and regulated to within 0.15°C of the desired set points with the aid of PID controlled modulating valves. As for the compressor frequency modulation, a variable speed drive was retrofitted to the system to study the part load performances. The performances of the valves were reviewed from the perspective of superheat control, cooling load, heat exchangers' effectiveness and internal entropy generation.

Original languageEnglish (US)
Title of host publication5th Asian Conference on Refrigeration and Air Conditioning, ACRA 2010 - Green Breeze from Asia
Subtitle of host publicationFrontiers of Refrigerants, Heat Transfer and System
PublisherJapan Society of Refrigeration and Air Conditioning Engineering (JSRAE)
ISBN (Electronic)9781634391252
StatePublished - Jan 1 2010
Event5th Asian Conference on Refrigeration and Air Conditioning - Green Breeze from Asia: Frontiers of Refrigerants, Heat Transfer and System, ACRA 2010 - Tokyo, Japan
Duration: Jun 7 2010Jun 9 2010

Publication series

Name5th Asian Conference on Refrigeration and Air Conditioning, ACRA 2010 - Green Breeze from Asia: Frontiers of Refrigerants, Heat Transfer and System

Other

Other5th Asian Conference on Refrigeration and Air Conditioning - Green Breeze from Asia: Frontiers of Refrigerants, Heat Transfer and System, ACRA 2010
CountryJapan
CityTokyo
Period06/7/1006/9/10

Keywords

  • Electronic expansion valve
  • Entropy Generation
  • Superheat control
  • Thermostatic expansion valve

ASJC Scopus subject areas

  • Engineering(all)
  • Environmental Engineering

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