Effect of internal heat exchanger to the performance of vapor compression cycle using refrigerant R32

In this study, a new model of a solar combined ejector-vapor compression refrigeration system has been considered. The system is equipped with an internal heat exchanger to enhance the performance of the cycle. The effects of working fluid and operating conditions on the system performance including COP, entrainment ratio (Ï‰), compression ratio (rp) and exergy efficiency were investigated. Some working fluids suggested are: R114, R141b, R123, R245fa, R600a, R365mfc, R1234ze(e) and R1234ze(z). The results show that R114 and R1234ze(e) yield the highest COP and exergy efficiency followed by R123, R245fa, R365mfc, R141b, R152a and R600a. It is noticed that the COP value of the new solar ejector-vapor compression refrigeration cycle is higher than that of the conventional ejector cycle with R1234ze(e) for all operating conditions. This paper also demonstrates that R1234ze(e) will be a suitable refrigerant in the solar combined ejector-vapor compression refrigeration system, due to its environmental friendly properties and better performance.Â ABSTRAK: Kajian ini menganalisa model baru sistem penyejukan mampatan gabungan ejektor-wap solar.Sistem ini dilengkapi dengan penukar haba dalaman untuk meningkatkan prestasi kitaran.Kesan bendalir bekerja dan keadaan operasi pada prestasi sistem termasuk COP, nisbah pemerangkapan (Ï‰), nisbah mampatan (rp) dan kecekapan eksergi telah disiasat.Beberapa bendalir bekerja yang dicadangkan adalah: R114, R141b, R123, R245fa, R600a, R365mfc, R1234ze(e) dan R1234ze(z).Hasil kajian menunjukkan R114 dan R1234ze(e) menghasilkan COP dan kecekapan eksergi tertinggi diikuti oleh R123, R245fa, R365mfc, R141b, R152a dan R600a.Didapati nilai COP kitaran penyejukan mampatan bagi ejektor-wap solar baru adalah lebih tinggi daripada kitaran ejektor konvensional dengan R1234ze(e) bagi semua keadaan operasi.Kertas kerja ini juga menunjukkan bahawa R1234ze(e) boleh menjadi penyejuk yang sesuai dalam sistem penyejukan mampatan gabungan ejektor -wap solar, kerana ianya mempunyai prestasi yang lebih baik serta sifatnya yang lebih mesra alam sekitar.Â KEYWORDS: environmental friendly refrigerants; solar combined ejector-vapor compression cycle; R1234ze(e)

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Performance Analysis of Single Stage Compression Cycle with an Internal Heat Exchanger

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.753-755.1401 ◽

2013 ◽

Vol 753-755 ◽

pp. 1401-1404

Author(s):

Gui Jun Xue ◽

Da Wei Liang ◽

Guang Da Liu ◽

Shui Qing Li ◽

Zhen Jiang Zhou

Keyword(s):

High Pressure ◽

Heat Exchanger ◽

Performance Analysis ◽

Internal Heat ◽

Single Stage ◽

Outlet Temperature ◽

Outlet Pressure ◽

Internal Heat Exchanger ◽

Compression Cycle ◽

Increasing Trend

With the increase of outlet pressure to compressor, all cycle COP is a reducing trend except R744, in addition, R744 compression cycle has an optimum high pressure. When the inlet temperatures of compressor gradually increase, the performances of all cycles basically unchanged, but the R744 compression cycle has an increasing trend. With the increasing of outlet temperature to the condenser, the performances of all cycles are decreased; instead with increasing of the evaporating temperature, all cycle COP is an increasing trend.

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Moving-Boundary Heat Exchanger Models With Variable Outlet Phase

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.2977466 ◽

2008 ◽

Vol 130 (6) ◽

Cited By ~ 26

Author(s):

Brian D. Eldredge ◽

Bryan P. Rasmussen ◽

Andrew G. Alleyne

Keyword(s):

Heat Exchanger ◽

Moving Boundary ◽

System Level ◽

Phase System ◽

Vapor Compression ◽

Vapor Compression Cycle ◽

Compression Cycle ◽

Cycle Systems ◽

Level Model ◽

And Control

Vapor compression cycle systems using accumulators and receivers inherently operate at or near a transition point involving changes of phase at the heat exchanger outlets. This work introduces a condenser/receiver model and an evaporator/accumulator model developed in the moving-boundary framework. These models use a novel extension of physical variable definitions to account for variations in refrigerant exit phase. System-level model validation results, which demonstrate the validity of the new models, are presented. The model accuracy is improved by recognizing the sensitivity of the models to refrigerant mass flow rate. The approach developed and the validated models provide a valuable tool for dynamic analysis and control design for vapor compression cycle systems.

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Performance Analysis of Single Stage Compression Cycle with an Internal Heat Exchanger

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.602-604.1068 ◽

2012 ◽

Vol 602-604 ◽

pp. 1068-1071

Author(s):

Hong Li Wang ◽

Hui Qin Liu ◽

Qi Long Tang ◽

Ning Jia

Keyword(s):

High Pressure ◽

Heat Exchanger ◽

Performance Analysis ◽

Internal Heat ◽

Single Stage ◽

Outlet Temperature ◽

Internal Heat Exchanger ◽

Compression Cycle ◽

Increasing Trend

With increasing of high pressure, the performances of all kinds refrigerants except for R744 are all declined, transcritical R744 compression cycle has an optimum high pressure. With increasing of the evaporating temperature, all cycle COP is an increasing trend, with increasing of outlet temperature of condenser, the performances of all cycles are decreased. Under the same comparison conditions, the performance of R22 refrigerant cycle is superior to the cycles of other refrigerants, and the cycle of R11 refrigerant has the worst performance.

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Energy, Exergy, and Environmental (3E) Analysis of Hydrocarbons as Low GWP Alternatives to R134a in Vapor Compression Refrigeration Configurations

Applied Sciences ◽

10.3390/app11136226 ◽

2021 ◽

Vol 11 (13) ◽

pp. 6226

Author(s):

Morteza Ghanbarpour ◽

Adrián Mota-Babiloni ◽

Bassam E. Badran ◽

Rahmatollah Khodabandeh

Keyword(s):

Heat Exchanger ◽

Environmental Impact ◽

Impact Analysis ◽

Internal Heat ◽

Refrigeration Cycle ◽

Vapor Compression ◽

Two Stage ◽

Internal Heat Exchanger ◽

Vapor Injection ◽

Flash Tank

The phase-down of hydrofluorocarbons and substitution with low global warming potential values are consequences of the awareness about the environmental impacts of greenhouse gases. This theoretical study evaluated the energy and exergy performances and the environmental impact of three vapor compression system configurations operating with the hydrocarbons R290, R600a, and R1270 as alternatives to R134a. The refrigeration cycle configurations investigated in this study include a single-stage cycle, a cycle equipped with an internal heat exchanger, and a two-stage cycle with vapor injection. According to the results, the alternative hydrocarbon refrigerants could provide comparable system performance to R134a. The analysis results also revealed that using an internal heat exchanger or a flash tank vapor injection could improve the system’s efficiency while decreasing the heating capacity. The most efficient configuration was the two-stage refrigeration cycle with vapor injection, as revealed by the exergy analysis. The environmental impact analysis indicated that the utilization of environmentally-friendly refrigerants and improving the refrigeration system’s efficiency could mitigate equivalent CO2 emissions significantly. The utilization of hydrocarbons reduced the carbon footprint by 50%, while a 1% to 8% reduction could be achieved using the internal heat exchanger and flash tank vapor injection.

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Performance Analysis of Two Stage Compression Cycle with an Internal Heat Exchanger

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.540.110 ◽

2014 ◽

Vol 540 ◽

pp. 110-113

Author(s):

Hong Li Wang ◽

Ning Jia ◽

Jing Rui Tian

Keyword(s):

High Pressure ◽

Heat Exchanger ◽

Internal Heat ◽

Outlet Temperature ◽

Minimum Level ◽

Two Stage ◽

Intermediate Pressure ◽

Internal Heat Exchanger ◽

Compression Cycle ◽

Increasing Trend

With increasing of the evaporating temperature, the two stage compression cycle with an internal exchanger’s COP has an increasing trend. In addition, R744 achieves the highest COP, and the R12 achieves the minimum level. With increasing of the high pressure and the outlet temperature of the condenser, the two stage compression cycle has a down trend. In terms of the increasing intermediate pressure, the two stage cycle with different refrigerants has different performance: R12’s COP has a downtrend with the pressure changing from 1MPa-3MPa, the rest refrigerants all increased first, and then decreased. Except for R12, they all have optimal intermediate pressure.

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