scholarly journals Experimental evaluation of internal heat exchanger influence on R-22 window air conditioner retrofitted with R-407C

2010 ◽  
Vol 14 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Raghavan Vijayan ◽  
Pss Srinivasan
Keyword(s):  
Heat Exchanger ◽  
Experimental Evaluation ◽  
Internal Heat ◽  
Coefficient Of Performance ◽  
Air Conditioner ◽  
Alternative Refrigerant ◽  
Internal Heat Exchanger ◽  
The Given

The performance of one ton of refrigeration window air conditioner working with R-22 and retrofitted with eco friendly alternative refrigerant R-407C is experimentally investigated An internal heat exchanger is also added to the same air conditioner to provide liquid overfeeding operation. When retrofitting the R-22 system with R-407C, the coefficient of performance is found to drop by 7.28%, however when internal heat exchanger is included the performance is improved. It is observed that the inclusion of internal heat exchanger has increased the coefficient of performance by 5.86% when running on R-22 and 6.18% when running on R-407C, under the given conditions.

THERMODYNAMIC ANALYSIS AND EXPERIMENTAL RESEARCH OF TRANSCRITICAL CO2 CYCLE WITH INTERNAL HEAT EXCHANGER AND DUAL EXPANSION

2013 ◽  
Vol 21 (01) ◽  
pp. 1350005 ◽  
Author(s):  
Z. WANG ◽  
Y. GONG ◽  
X. H. WU ◽  
W. H. ZHANG ◽  
Y. L. LU
Keyword(s):  
Heat Exchanger ◽  
Experimental Evaluation ◽  
Pressure Fluctuations ◽  
Internal Heat ◽  
Energy Performance ◽  
Evaporation Temperature ◽  
Internal Heat Exchanger ◽  
Side Pressure ◽  
Wide Range ◽  
Compressor Power

This work presents the experimental evaluation of the energy performance of transcritical CO2 refrigeration and heat pump systems. The optimal gas cooler pressures and the optimal COP have been analyzed from a thermodynamic point of view. The systems used a new dual expansion valve and a balance CO2 liquid receiver adjustment device, which can control high and low side pressure effectively. Moreover, we demonstrate the influence of the internal heat exchanger (IHX) on the systems' performances, on the basis of the analysis of the relative COP index RCOPI, the compressor power index RPCI and other parameters which can confirm the truth of. The experimental evaluation covers five evaporating levels (-10 to 10°C) and in a wide range of gas cooler pressures (75 to 120 bar). It is concluded that with the IHX system, compressor power is relatively low when the high side pressure is over 100 bar, and the evaporation temperature is below 0°C. The COP of the system without the IHX is slightly higher than the system with the IHX; it is increasing about 3% to 5%, when the evaporation temperature is over 5°C. Relative to the single expansion process, the dual expansion cycle can decrease the influence of pressure fluctuations of CO2 supercritical fluid and liquid mixture on the systems.

scholarly journals Experimental evaluation of an internal heat exchanger in a CO2 subcritical refrigeration cycle with gas-cooler

2015 ◽  
Vol 80 ◽  
pp. 31-41 ◽  
Author(s):  
Rodrigo Llopis ◽  
Carlos Sanz-Kock ◽  
Ramón Cabello ◽  
Daniel Sánchez ◽  
Enrique Torrella
Keyword(s):  
Heat Exchanger ◽  
Experimental Evaluation ◽  
Internal Heat ◽  
Refrigeration Cycle ◽  
Internal Heat Exchanger

Theoretical Analysis and Experimental Researches on Internal Heat Exchanger in CO2 Trans-Critical Cycle

2012 ◽  
Vol 204-208 ◽  
pp. 4336-4342
Author(s):  
Hui Xia Lu ◽  
Jing Lv ◽  
Zhe Bin He ◽  
Jin Yu Wang ◽  
Jia Wei Zhou
Keyword(s):  
Heat Exchanger ◽  
Internal Heat ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Outlet Temperature ◽  
Internal Heat Exchanger ◽  
High Side ◽  
Side Pressure ◽  
Experimental Researches ◽  
Regenerative Cycle

The change of system performance caused by regenerative cycle in different operating conditions was analyzed in this paper, comparing the cycle with or without internal heat exchanger in a CO2 trans-critical cycle. We analyzed theoretically the performance of CO2 trans-critical cycle with the internal heat exchanger, and found that the coefficient increased with the decreasing of the high side pressure and the increasing of outlet temperature in gas cooler, in a certain range of the high side pressure and outlet temperature. The evaporation temperature could be raised when the system with internal heat exchanger and at the same time the coefficient of performance could be improved obviously. At lower high side pressure, the performance coefficient could be improved significantly by increasing the suction superheat. The higher the gas cooler outlet temperature was, the more obvious the increase was.

Performance characteristics of natural-refrigerants- based ejector expansion refrigeration cycles

2009 ◽  
Vol 223 (5) ◽  
pp. 543-550 ◽  
Author(s):  
J Sarkar
Keyword(s):  
Heat Exchanger ◽  
Internal Heat ◽  
Area Ratio ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Internal Heat Exchanger ◽  
Optimum Parameters ◽  
And Performance ◽  
Vapour Compression ◽  
Cycle Temperature

The thermodynamic analyses and comparison of three natural-refrigerants-based vapour compression refrigeration cycles (ammonia, isobutane, and propane) are presented in this article using a constant pressure mixing ejector as an expansion device. Optimization of the area ratio of the ejector is done based on maximum cooling coefficient of performance (COP) and performance improvement for different operating conditions. The effect of using an internal heat exchanger is studied as well. Results show that optimum area ratio and cooling COP increases with a decrease in cycle temperature lift, whereas the COP improvement over basic expansion cycle increases with the increase in cycle temperature lift. Study shows that the optimum parameters, as well as performance using the ejector as an expansion device, are strongly dependent on the refrigerant properties as well as the operating conditions. The optimum area ratio is maximum for ammonia and minimum for propane, whereas maximum cooling COPs are similar. Using the ejector as an expansion device, propane yields a maximum COP improvement of 26.1 per cent followed by isobutane (22.8 per cent) and ammonia (11.7 per cent) for studies ranges. The effect of using an internal heat exchanger in the ejector expansion refrigeration cycle is found to be not profitable.

Effects of an Internal Heat Exchanger in a Refrigerant System with Carbon Dioxide on Its Cooling Coefficient of Performance and Cooling Capacity

2008 ◽  
Vol 34 (5) ◽  
pp. 505-512 ◽  
Author(s):  
Shogo Tamaki ◽  
Yuuko Fujii ◽  
Yohsuke Matsushita ◽  
Hideyuki Aoki ◽  
Takatoshi Miura ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Heat Exchanger ◽  
Internal Heat ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Internal Heat Exchanger

Experimental evaluation of the effect of an internal heat exchanger on a transcritical CO2 ejector system

2011 ◽  
Vol 12 (2) ◽  
pp. 146-153 ◽  
Author(s):  
Xiao-xiao Xu ◽  
Guang-ming Chen ◽  
Li-ming Tang ◽  
Zhi-jiang Zhu ◽  
Shuang Liu
Keyword(s):  
Heat Exchanger ◽  
Experimental Evaluation ◽  
Internal Heat ◽  
Internal Heat Exchanger ◽  
Ejector System

Experimental Study of an Internal Heat Exchanger Influence on R134a Automobile Air Conditioning System

2012 ◽  
Vol 165 ◽  
pp. 145-149 ◽  
Author(s):  
Salman Bahrami ◽  
Hasan Mohammad Beigi ◽  
Mohammad Hosein Sabour
Keyword(s):  
High Pressure ◽  
Heat Exchanger ◽  
Air Conditioning ◽  
Internal Heat ◽  
Low Pressure ◽  
Work Conditions ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Air Conditioning System ◽  
Internal Heat Exchanger

Liquid-suction or internal heat exchanger (IHX) is installed in vapor compression refrigeration systems to exchange energy between cool low-pressure gas and warm high-pressure liquid refrigerant. The aim of this research is to experimentally evaluate the effect of IHX adaptation in an automotive air conditioning system focusing on evaporator working conditions. In this new design of IHX, the high-pressure liquid passes through the central channel and the low-pressure vapor flows in several parallel channels in the opposite direction. The experimental set-up has been made up of original components of the air conditioning system of a medium sedan car, specially designed and built to analyze vehicle A/C equipments under real work conditions. The results show that low pressure drop will be imposed on the cycle using this type of IHX. Also, they confirm considerable decrease of compressor power consumption; it is intensified at higher evaporator air flow. A significant improvement of the coefficient of performance will be achieved with IHX too. The influence of operating conditions has been also discussed in this paper.

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