Ammonia chiller performance enhancement by implementation of ejector overfeed cycle with brazed plate evaporator

Neal Lawrence, Stefan Elbel, Joe Zheng, Mario Wenzel, Pega Hrnjak

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

Abstract

Ammonia has long been considered one the most promising refrigerants for refrigeration applications due to its favorable thermodynamic properties that yield high COP compared to most other common fluids. Evaporator overfeed in ammonia systems is often accomplished by means of a motor-driven pump; however, a simpler and more reliable method for overfeeding would be to use a liquid recirculation ejector. This paper presents the results of a study investigating the improvement that can be achieved in evaporator and cycle performance for a 20 kW nominal capacity ammonia chiller by overfeeding the evaporator. A two-phase ammonia ejector was designed based on previous in-house knowledge and experience with liquid recirculation ejectors; baseline system and ejector overfeed system capacity, COP, and evaporator performance are presented and compared, with simultaneous capacity and COP improvements of 28 and 22 %, respectively, observed with the overfeed system mainly due to the elimination of the superheated portion of the evaporator.

Original languageEnglish (US)
Title of host publication14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020 - Proceedings
PublisherInternational Institute of Refrigeration
Pages423-428
Number of pages6
ISBN (Electronic)9782362150401
DOIs
StatePublished - 2020
Event14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020 - Virtual, Kyoto, Japan
Duration: Dec 7 2020Dec 9 2020

Publication series

NameRefrigeration Science and Technology
Volume2020-December
ISSN (Print)0151-1637

Conference

Conference14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020
CountryJapan
CityVirtual, Kyoto
Period12/7/2012/9/20

Keywords

  • Brazed-plate evaporator
  • Ejector work recovery
  • Evaporator overfeed
  • Liquid recirculation
  • Low-charge ammonia

ASJC Scopus subject areas

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

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