scholarly journals Preliminary study on vapor compression refrigeration cycle with an internal phase-separating loop using a R290/R600a mixture in air conditioner

2019 ◽  
Author(s):  
Mustaqim ◽  
Berkah Fajar ◽  
Tony Suryo Utomo ◽  
S. H. Winoto
2019 ◽  
Vol 25 (7) ◽  
pp. 1-20
Author(s):  
Yasser Abdul Lateef Ghani ◽  
Abdul Hadi N. Khalifa

A time series analysis can help to observe the behavior of the system and specify the system faults. In addition, it also helps to explain the various energy flows in the system and further aid in reducing the thermodynamic losses. The intelligent supervisory LabVIEW software can monitor the incoming data from the system by using Arduino microcontroller and calculates the important parameters. Energy, exergy, and anergy analysis present in this paper to investigate the system performance as well as its components. To accomplish this, a 4-ton vertical split air conditioner based on vapor compression refrigeration cycle charged with refrigerant R-22 was modified for experimental analysis. The results showed that during 5400 secs of experimental study, the system shut down once by the software for 5 min. The volumetric and isentropic efficiencies of the compressor were 79.85 % and 64.48 % respectively. The maximum entropy generation was due to the compressor of 3.4 W/K while the maximum anergy was due to the condenser of 1.39 kW. The exergy efficiencies of the compressor, condenser, and the evaporator were 73.57, 40.18, and 47.45 % respectively. The system and Carnot COP were 2.53 and 4.9 respectively. The exergy efficiency of the air conditioning system was 48.7 %.  


2020 ◽  
Vol 15 (3) ◽  
pp. 398-408
Author(s):  
I Ouelhazi ◽  
Y Ezzaalouni ◽  
L Kairouani

Abstract From the last few years, the use of efficient ejector in refrigeration systems has been paid a lot of attention. In this article a description of a refrigeration system that combines a basic vapor compression refrigeration cycle with an ejector cooling cycle is presented. A one-dimensional mathematical model is developed using the flow governing thermodynamic equations based on a constant area ejector flow model. The model includes effects of friction at the constant-area mixing chamber. The current model is based on the NIST-REFPROP database for refrigerant property calculations. The model has basically been used to determine the effect of the ejector geometry and operating conditions on the performance of the whole refrigeration system. The results show that the proposed model predicts ejector performance, entrainment ratio and the coefficient of performance of the system and their sensitivity to evaporating and generating temperature of the cascade refrigeration cycle. The simulated performance has been then compared with the available experimental data from the literature for validation.


2007 ◽  
Vol 259 (2) ◽  
pp. 195-200 ◽  
Author(s):  
S. Figueroa-Gerstenmaier ◽  
M. Francova ◽  
M. Kowalski ◽  
M. Lisal ◽  
I. Nezbeda ◽  
...  

2019 ◽  
Vol 130 ◽  
pp. 01007
Author(s):  
Ekadewi Anggraini Handoyo ◽  
Andriono Slamet ◽  
Muhammad Danang Birowosuto

Garden by The Bay in Singapore is the world’s largest coolest conservatories. Although it is located in tropics and uses so many glasses, its electricity consumption is as much as a commercial building. The key to this low consumption is in air cooling technology. Air used for cooling the conservatories is dehumidified first using liquid desiccants before cooled. The same technology was implemented to a single-split air conditioner (AC) that works on a vapor-compression refrigeration cycle. The experiments were conducted in a room with opened and closed door. Instead of using a liquid desiccant, the experiment used a solid desiccant, i.e., silica gel which thickness was 6 mm and 8 mm with density equals to 1.27 gr cm–3. From the experiment, it is found that: (i) the thicker the silica gel, the higher outlet air temperature from silica gel, (ii) less condensate will be produced when the silica gel used is thicker, (iii) silica gel is suitable for reducing humidity of outdoor/fresh air, and (iv) the electricity consumption saving for inserting 8 mm silica gel is only 4 % when the door is closed and 31 % when the door is opened.


2019 ◽  
Vol 18 (2) ◽  
pp. 19
Author(s):  
L. S. Santana ◽  
J. Castro ◽  
L. M. Pereira

Vapor-compression refrigeration systems require a significant amount of electrical energy. Therefore, there is a need for finding efficient ways of operating this equipment, reducing their energy consumption. The use of heat exchangers between the suction line and the liquid line can produce a better performance of the thermodynamic cycle, as well as reduce it. The present work aims at an experimental analysis of the suction/liquid heat exchanger present in a freezer running with refrigerant fluid R-134a. Three different scenarios were used in order to evaluate the thermal performance of the refrigeration cycle. The first scenario was the conventional freezer set up to collect the required data for further comparison. Moreover, the second and third scenarios were introduced with a 20 cm and 40 cm suction/liquid heat exchanger, respectively, into the system. From the experiments, it was observed that the heat exchange does not significantly affect the coefficient of performance (COP) of the freezer. It was concluded from this work that the best scenario analyzed was the 20 cm suction/liquid heat exchanger where most of the thermodynamic properties were improved, one of them being the isentropic efficiency.


2006 ◽  
Author(s):  
Ali Kilicarslan ◽  
Norbert Mu¨ller

The performance comparison of water as a refrigerant (R718) with some prevailing refrigerants including R717, R290, R134a, R12, R22, and R152a is presented. A computer program simulating an actual vapor compression refrigeration cycle including subcooling was developed to calculate the coefficient of performances (COPs) for the different refrigerants. Evaporator temperatures above which water yields a better COP over the other refrigerants are investigated for subcooling case. The effect of degree of subcooling on the COPs is elaborated. For most of the refrigerants (R290, R134a, R12, R22, and R152a) the COP increases by around one percent (1%) per one Kelvin (1K) subcooling, while the COP for R718 and R717 increases by around 0.2 % and 0.5 % per one Kelvin (1K) subcooling. At constant evaporator temperature, increasing the degree of subcooling results in decrease of the relative COP gain of R718. R718 gives the highest relative COP increase at constant condenser temperature and polytropic efficiency. The effect of polytropic efficiency on the performance is also investigated. It is observed that the evaporator temperature range at which R718 presents a better COP than other refrigerants increases with increasing values of polytropic compressor efficiency if the degree of subcooling is kept constant.


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