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

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

doi:10.18462/iir.gl.2020.1013

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

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

Mechanical Science and Engineering

Research output: Chapter in Book/Report/Conference proceeding › Conference 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 language	English (US)
Title of host publication	14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020 - Proceedings
Publisher	International Institute of Refrigeration
Pages	423-428
Number of pages	6
ISBN (Electronic)	9782362150401
DOIs	https://doi.org/10.18462/iir.gl.2020.1013
State	Published - 2020
Event	14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020 - Virtual, Kyoto, Japan Duration: Dec 7 2020 → Dec 9 2020

Publication series

Name	Refrigeration Science and Technology
Volume	2020-December
ISSN (Print)	0151-1637

Conference

Conference	14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020
Country	Japan
City	Virtual, Kyoto
Period	12/7/20 → 12/9/20

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

Access to Document

10.18462/iir.gl.2020.1013

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Cite this

Lawrence, N., Elbel, S., Zheng, J., Wenzel, M., & Hrnjak, P. (2020). Ammonia chiller performance enhancement by implementation of ejector overfeed cycle with brazed plate evaporator. In 14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020 - Proceedings (pp. 423-428). (Refrigeration Science and Technology; Vol. 2020-December). International Institute of Refrigeration. https://doi.org/10.18462/iir.gl.2020.1013

Ammonia chiller performance enhancement by implementation of ejector overfeed cycle with brazed plate evaporator. / Lawrence, Neal; Elbel, Stefan; Zheng, Joe; Wenzel, Mario; Hrnjak, Pega.

14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020 - Proceedings. International Institute of Refrigeration, 2020. p. 423-428 (Refrigeration Science and Technology; Vol. 2020-December).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Lawrence, N, Elbel, S, Zheng, J, Wenzel, M & Hrnjak, P 2020, Ammonia chiller performance enhancement by implementation of ejector overfeed cycle with brazed plate evaporator. in 14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020 - Proceedings. Refrigeration Science and Technology, vol. 2020-December, International Institute of Refrigeration, pp. 423-428, 14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020, Virtual, Kyoto, Japan, 12/7/20. https://doi.org/10.18462/iir.gl.2020.1013

Lawrence N, Elbel S, Zheng J, Wenzel M, Hrnjak P. Ammonia chiller performance enhancement by implementation of ejector overfeed cycle with brazed plate evaporator. In 14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020 - Proceedings. International Institute of Refrigeration. 2020. p. 423-428. (Refrigeration Science and Technology). https://doi.org/10.18462/iir.gl.2020.1013

Lawrence, Neal ; Elbel, Stefan ; Zheng, Joe ; Wenzel, Mario ; Hrnjak, Pega. / Ammonia chiller performance enhancement by implementation of ejector overfeed cycle with brazed plate evaporator. 14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020 - Proceedings. International Institute of Refrigeration, 2020. pp. 423-428 (Refrigeration Science and Technology).

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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.",

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note = "Publisher Copyright: {\textcopyright} 2020 International Institute of Refrigeration. All rights reserved. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.; 14th IIR Gustav-Lorentzen Conference on Natural Fluids, GL 2020 ; Conference date: 07-12-2020 Through 09-12-2020",

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AB - 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.

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