Thermodynamic analysis of capacity-control schemes for refrigeration and air-conditioning systems

M. Yaqub; Syed M. Zubair

doi:10.1016/0360-5442(95)00111-5

Thermodynamic analysis of capacity-control schemes for refrigeration and air-conditioning systems

M. Yaqub
, Syed M. Zubair^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

9 Scopus citations

Abstract

Cylinder unloading and suction-gas throttling schemes are studied to reduce the capacity of refrigeration and air-conditioning systems when operating at reduced load. In the first scheme, an unloaded valve is used to unload one or more cylinders at part-load conditions. The unloading of cylinders reduces the mass-flow rate of refrigerant in the system and thus reduces the system capacity, whereas in suction-gas throttling, a throttling valve is needed before the compressor to reduce the mass-flow rate through the compressor. These schemes are discussed for HFC-134a and compared on the basis of the first and second laws of thermodynamics. A hot-gas by-pass capacity-control scheme is also examined in terms of system coefficient of performance (COP) and irreversible component losses. It is found that the cylinder-unloading scheme is best and has the highest COP and minimum irreversible losses at any system capacity.

Original language	English
Pages (from-to)	463-472
Number of pages	10
Journal	Energy
Volume	21
Issue number	6
DOIs	https://doi.org/10.1016/0360-5442(95)00111-5
State	Published - 1996

Bibliographical note

Funding Information:
standpoint. However, the capacity reduction is limited to 25, 50, or 75% for a multi-cylinder, reciprocating compressor. Although the hot-gas by-pass scheme has the lowest COP and highest irreversible losses, its use is normally recommended when very close temperature and humidity controls are required. Precise controls may also be achieved with the suction-gas-throttling scheme; the disadvantage here is that at lower capacity, the compressor-discharge temperature is increased, which may result in the development of several system-related problems. ~ Acknowledgement--The authors acknowledge support provided by King Fahd University of Petroleum and Minerals for this research project.

ASJC Scopus subject areas

Civil and Structural Engineering
Building and Construction
Pollution
Mechanical Engineering
Industrial and Manufacturing Engineering
Electrical and Electronic Engineering

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@article{f08d5293a7584eb29f0e0b03bfa02c1e,

title = "Thermodynamic analysis of capacity-control schemes for refrigeration and air-conditioning systems",

abstract = "Cylinder unloading and suction-gas throttling schemes are studied to reduce the capacity of refrigeration and air-conditioning systems when operating at reduced load. In the first scheme, an unloaded valve is used to unload one or more cylinders at part-load conditions. The unloading of cylinders reduces the mass-flow rate of refrigerant in the system and thus reduces the system capacity, whereas in suction-gas throttling, a throttling valve is needed before the compressor to reduce the mass-flow rate through the compressor. These schemes are discussed for HFC-134a and compared on the basis of the first and second laws of thermodynamics. A hot-gas by-pass capacity-control scheme is also examined in terms of system coefficient of performance (COP) and irreversible component losses. It is found that the cylinder-unloading scheme is best and has the highest COP and minimum irreversible losses at any system capacity.",

author = "M. Yaqub and Zubair, \{Syed M.\}",

note = "Funding Information: standpoint. However, the capacity reduction is limited to 25, 50, or 75\% for a multi-cylinder, reciprocating compressor. Although the hot-gas by-pass scheme has the lowest COP and highest irreversible losses, its use is normally recommended when very close temperature and humidity controls are required. Precise controls may also be achieved with the suction-gas-throttling scheme; the disadvantage here is that at lower capacity, the compressor-discharge temperature is increased, which may result in the development of several system-related problems. \textasciitilde{} Acknowledgement--The authors acknowledge support provided by King Fahd University of Petroleum and Minerals for this research project.",

year = "1996",

doi = "10.1016/0360-5442(95)00111-5",

language = "English",

volume = "21",

pages = "463--472",

journal = "Energy",

issn = "0360-5442",

number = "6",

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T1 - Thermodynamic analysis of capacity-control schemes for refrigeration and air-conditioning systems

AU - Yaqub, M.

AU - Zubair, Syed M.

N1 - Funding Information: standpoint. However, the capacity reduction is limited to 25, 50, or 75% for a multi-cylinder, reciprocating compressor. Although the hot-gas by-pass scheme has the lowest COP and highest irreversible losses, its use is normally recommended when very close temperature and humidity controls are required. Precise controls may also be achieved with the suction-gas-throttling scheme; the disadvantage here is that at lower capacity, the compressor-discharge temperature is increased, which may result in the development of several system-related problems. ~ Acknowledgement--The authors acknowledge support provided by King Fahd University of Petroleum and Minerals for this research project.

PY - 1996

Y1 - 1996

N2 - Cylinder unloading and suction-gas throttling schemes are studied to reduce the capacity of refrigeration and air-conditioning systems when operating at reduced load. In the first scheme, an unloaded valve is used to unload one or more cylinders at part-load conditions. The unloading of cylinders reduces the mass-flow rate of refrigerant in the system and thus reduces the system capacity, whereas in suction-gas throttling, a throttling valve is needed before the compressor to reduce the mass-flow rate through the compressor. These schemes are discussed for HFC-134a and compared on the basis of the first and second laws of thermodynamics. A hot-gas by-pass capacity-control scheme is also examined in terms of system coefficient of performance (COP) and irreversible component losses. It is found that the cylinder-unloading scheme is best and has the highest COP and minimum irreversible losses at any system capacity.

AB - Cylinder unloading and suction-gas throttling schemes are studied to reduce the capacity of refrigeration and air-conditioning systems when operating at reduced load. In the first scheme, an unloaded valve is used to unload one or more cylinders at part-load conditions. The unloading of cylinders reduces the mass-flow rate of refrigerant in the system and thus reduces the system capacity, whereas in suction-gas throttling, a throttling valve is needed before the compressor to reduce the mass-flow rate through the compressor. These schemes are discussed for HFC-134a and compared on the basis of the first and second laws of thermodynamics. A hot-gas by-pass capacity-control scheme is also examined in terms of system coefficient of performance (COP) and irreversible component losses. It is found that the cylinder-unloading scheme is best and has the highest COP and minimum irreversible losses at any system capacity.

UR - https://www.scopus.com/pages/publications/0029675373

U2 - 10.1016/0360-5442(95)00111-5

DO - 10.1016/0360-5442(95)00111-5

M3 - Article

AN - SCOPUS:0029675373

SN - 0360-5442

VL - 21

SP - 463

EP - 472

JO - Energy

JF - Energy

IS - 6

ER -

Thermodynamic analysis of capacity-control schemes for refrigeration and air-conditioning systems

Abstract

Bibliographical note

ASJC Scopus subject areas

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