Thermodynamic analyses of the CFC-12 and HFC-134a refrigeration cycles

Khan, Shamsul Hoda; Zubair, Syed M.

doi:10.1016/0360-5442(93)90031-8

Cited by 17 publications

(8 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the coefficient of performance (COP) for the CFC-12 and the HFC-134a differ by less than 10% [16,17], the refrigerant is not the only key ingredient that influences energy efficiency, hence these indirect effects. In this study, special consideration is given to the role the lubricant in the hermetic compressor plays.…”

Section: Materials and Designmentioning

confidence: 99%

A study of tribological durability with associated environmental impacts of a domestic refrigerator

Ciantar

Hadfield

2004

Materials & Design

View full text Add to dashboard Cite

Section: Materials and Designmentioning

confidence: 99%

A study of tribological durability with associated environmental impacts of a domestic refrigerator

Ciantar

Hadfield

2004

Materials & Design

View full text Add to dashboard Cite

“…Since entropy is a state function, its net change over the cycle is zero. Therefore, the contributions to the entropy Equation (11) gives the COP total of the system for one set of input data. The required input data can be measured experimentally from an actual operating system or calculated from the thermodynamic model, which is discussed in the latter part of the paper.…”

Section: Analysis Of the Cyclementioning

confidence: 99%

Design and rating of dedicated mechanical-subcooling vapour compression refrigeration systems

Khan

Zubair

2000

Proceedings of the Institution of Mechanical Engineers, Part A:

View full text Add to dashboard Cite

Subcooling of the refrigerant at the exit of the condenser in a vapour compression refrigeration system allows the refrigerant to enter the main cycle evaporator with a lower quality and thus allows the refrigerant to absorb more heat in the evaporator, thereby improving the coefficient of performance (COP) of the system. In a dedicated mechanical-subcooling vapour compression refrigeration system, the subcooling is performed by utilizing a small dedicated vapour compression refrigeration cycle. This cycle is coupled to the main cycle at the exit of the condenser. In this paper, thermodynamic models of the dedicated mechanical-subcooling systems are developed to simulate the actual performance of the system, particularly with respect to the subcooler saturation temperature in addition to the heat exchanger areas. It is demonstrated that the performance of the overall cycle is improved over the corresponding simple cycle and this improvement is found to be related to the refrigerant saturation temperature of the subcooler. The models are also used to predict an optimum distribution of the total heat exchanger area between the evaporator and condenser.

show abstract

“…This made way to the introduction of hydrofluorocarbons (hfCs) which have zero ozone depletion potential. hfCs matched the thermodynamic properties of CfCs [5][6][7][8], but showed poorer tribological performance in comparison to their predecessors [1]. The inability of hfCs to form surface films under normal compressor operating conditions contributed to their inferior tribological performance [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Novel experimental setup to assess Surfaces in tribo-contact lubricated by the next generation of environmentally friendly thermofluids

Bhutta¹,

Khan²,

Garland³

2019

Int. J. CMEM

View full text Add to dashboard Cite

Environmental concerns related to global warming and ozone depletion triggered the introduction of the fourth generation of thermofluids. amongst the recently introduced thermofluids, one of the most promising fourth generation of thermofluids are hydrofluoroethers (hfEs). hfEs have zero ozone depletion potential and have a lower global warming potential as compared to widely used thermofluids. The type of thermofluid used in a thermodynamic cycle directly affects the tribological performance of the system. hfEs have been reported to have good thermodynamic properties. The overall tribological performance of hfEs however have to be investigated in detail in order to fully assess the mechanical behaviour of interacting components utilizing these thermofluids. This study is concerned with the experimental test rig design modifications and commissioning to conduct tribological testing with hfEs as lubricants. This article covers the experimental test rig design and setup. Experiments to analyse the frictional force, the coefficient of friction and wear by using hydrofluororther-7000 (hfE-347mcc3) as lubrication medium have been conducted. Industrial applications were simulated by varying test conditions and the results are presented in this paper.

show abstract

Thermodynamic analyses of the CFC-12 and HFC-134a refrigeration cycles

Cited by 17 publications

References 6 publications

A study of tribological durability with associated environmental impacts of a domestic refrigerator

A study of tribological durability with associated environmental impacts of a domestic refrigerator

Design and rating of dedicated mechanical-subcooling vapour compression refrigeration systems

Novel experimental setup to assess Surfaces in tribo-contact lubricated by the next generation of environmentally friendly thermofluids

Contact Info

Product

Resources

About