Effect of capillary tube on the performance of a simple vapour compression refrigeration system
TL;DR: In this article, the effect of capillary tube geometry on the performance of refrigeration systems was studied using both physical models and mathematical modeling concepts, and the parameters stated above can be further optimized in order to enhance the performance.
Abstract: It is essential to study the effect of capillary tube geometry on the performance of refrigeration systems. The literature review focuses on the effect that geometrical parameters like capillary tube length, bore diameter, coil pitch, number of twist and twisted angle have on the pressure drop, coefficient of performance (COP) and mass flow rate of the system. These parameters can be further studied using physical models and mathematical modeling concepts. The parameters stated above can be further optimized in order to enhance the performance of the refrigeration system.
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TL;DR: In this paper, the effect of the configuration and the capillary tube diameter on the overall performance of a simple vapour compression refrigeration system was studied, and the experimental results revealed that the mass flow rate is maximum for the straight configuration and is least for the helical coiled configuration.
Abstract: The study of the expansion device in the simple vapour compression refrigeration system is necessary in order to understand the parameters which can enhance the overall performance of the system. The experimental study was done on the capillary tubes of 31 gauge, 36 gauge and 40 gauge and each test section was studied with three distinct configurations i.e. helical coiled, straight coiled and serpentine coiled configuration. The effect of the configuration and the capillary tube diameter on the overall performance of the system was studied. The findings of the experimental study revealed that the mass flow rate is maximum for the straight configuration and is least for the helical coiled configuration. The refrigeration effect was found to be maximum for the helical coiled configuration and was found to be least for straight coiled configuration. The compressor work was found to reduce as the load was increased on the system. Decreasing the capillary tube diameter increased the mass flow rate in the system and decreased the refrigeration effect produced.
9 citations
TL;DR: In this article, the effects of the relevant parameters on the flow characteristic of R134a and R-22 flowing through adiabatic helical capillary tubes were experimentally studied.
Abstract: Capillary tubes are used as expansion device in low capacity refrigeration machines like domestic refrigerators and window type air conditioners. The advantages of the capillary tube over other expansion devices are simple, inexpensive and cause compressor to start at low torque as the pressure across the capillary tube equalize during the off-cycle. The flow characteristics of refrigerants through capillary tubes have been studied extensively in past six decades, both experimentally and analytically, most of these studies mainly focused on straight capillary tubes. In this thesis, the effects of the relevant parameters on the flow characteristic of R134a and R-22 flowing through adiabatic helical capillary tubes were experimentally studied. The capillary tubes' diameter, coil diameter, and parameters relating to flow conditions such as inlet pressures and degree of sub cooling were the major parameters investigated. In this thesis, the CFD analysis is to determine the heat transfer rate, pressure drop, velocity, mass flow rate and heat transfer coefficient for the fluids R134A and R-22 with different tube and coil diameters. Thermal analysis is to determine the temperature distribution and heat flux for copper and aluminum as tube materials.3D modeling is done pro-engineer and analysis is done in ANSYS software.
2 citations
28 Mar 2021
TL;DR: In this paper, the effect of capillary tube on the performance of VCR system is discussed, and the results of straight and helical type of Capillary tubes are studied.
Abstract: Vapor Compression refrigeration system is most commonly available system in day to day life from home to malls in India. It is necessary to improve the performance of system. The study is mainly focus on the improvement of performance. Out of different parameter, the literature review covers the effect of capillary tube on the performance of system. It covers the experimental and numerical study on effect of capillary tube. The results of straight and helical type of capillary tubes are studied. The study also covers the CFD analysis for the different length and diameters of capillary tubes and find out the optimize size.
2 citations
Dissertation•
04 Nov 2009
1 citations
01 Jan 2021
TL;DR: In this article, the domestic refrigerator compressor is interconnected with separate indoor unit of air conditioner and one more capillary tube is augmented with the existing refrigeration unit with indoor unit.
Abstract: Human comfort demand is raised day to day due to climate change, global warming and other environmental issues. Conventional air conditioners provide the human comfort; however, other side it consumes high electricity. So, main objective of the study is to reduce the power consumption. In this study, the domestic refrigerator compressor is interconnected with separate indoor unit of air conditioner. In addition, also one more capillary tube is augmented with the existing refrigeration unit with air conditioner indoor unit. An attempt has been made to investigate the performance parameters for both cases with four different coiling cabinet volumes of 44.4, 3.41, 2.25 and 1.5 m3. The results showed that more refrigeration effect is achieved with augmented one capillary tube in second case condition and the temperature and relative humidity have obtained as 23 °C and 50%, respectively. The power consumption compared to same capacity of existing air conditioner is obtained with 1/3rd times of power for small cooling cabinet area.
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TL;DR: In this paper, a comparison between four different refrigerants and finding out the most suitable one for miniature refrigerator is presented and it is found that NH3 gives the highest COP but because of its drawbacks like corrosive nature, fouling smell and highly toxic nature R134a is selected for the system.
Abstract: Recently in most of the studies mesoscale vapour compression refrigerator is integrated in high power microelectronic packaging and it offers a new cooling solution. Thermodynamic efficiency of such system depends on its operating temperatures. However, important practical issues like system design, sizing, cost, safety, reliability etc. depends on the type of refrigerant selected for given application. Now a days, global warming and ozone layer depletion are the prior issues to be considered while selecting the refrigerant. This work presents a comparison between four refrigerants and finding out the most suitable one for miniature refrigerator. In this work it is found that NH3 gives the highest COP but because of its drawbacks like corrosive nature, fouling smell and highly toxic nature R134a is selected for the system. Nomenclature Q Heat (W) W Power input (W) h Specific enthalpy (kJ/kg) T Temperature (0C) COP Coefficient of performance RE Refrigerating effect Greek Symbols η efficiency Subscripts C compressor c condenser e evaporator Introduction In recent years the development of power electronic devices [1] has led to many thermal issues. Air cooling technology has been in use for cooling of electronic devices since many years. But now a days liquid cooling is also attracting increasing interest as it is more effective than air cooling so it becomes necessary to develop a new technique which will serve the purpose. From the study of various alternatives such as Heat pipe, Liquid immersion, Thermoelectric, VCR and Jet impingement [2], the vapour compression system is found to be most effective for dissipating heat[3,4,5]. For developing such a small size refrigerator it is necessary to select the type of refrigerant to be used before designing the system [6]. There is no general rule governing the selection of refrigerants. There are of course five basic criteria thermo physical properties, technical aspects, economic aspects, safety and environment factors. Increasing concern about climate change has resulted in the developments of efficient and energy conserving refrigerants. New refrigerants are developed keeping in mind its effect on Ozone Depletion potentail (ODP) and Global Warming Potential (GWP) [7]. Considering the contribution to climate change it is important to select the refrigerant considering their performance merits and properties. Hence in this investigation a comparative study of four different refrigerants is done. Table-1 shows different properties and applications of refrigerants. Table-1 Properties and applications of various refrigerants. Sr. No. Refrigerant Boiling Point Critical Temperature Properties Applications 1 Ammonia (NH3)R717 -33 0C 1330C Penetrating smell, Non-flammable but Explosive, efficient, Attacks copper, No ODP and GWP, Highly toxic. Large industrial plants. Since it attacks copper, used in open type reciprocating or screw compressors and steel pipes 2 R12 (CCl2F2) -30 0C 1120C Has little odour, Colourless, Non-flammable, stable and Noncorrosive, Has ODP and GWP Small plants with reciprocating compressors, used in domestic and commercial refrigeration. 3 R22 (CHClF2) -40.8 0C 960C Colourless, Non-flammable, Noncorrosive and stable, Has ODP and GWP Packaged air conditioning unit where size and economy of equipment are important. 4 R134a (CH2FCF3) -260C Colourless, Non-flammable, Noncorrosive Nontoxic and stable, GWP-1300 Centrifugal and high speed screw compressor, widely used automobile A/C. Effect of refrigerant type on COP
3 citations
"Effect of capillary tube on the per..." refers methods in this paper
...M.M.Tayde et al. (2013) compared the performance of a miniature vapour compression refrigeration system with four different refrigerants namely NH3, R12, R22 and R134a....
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Dissertation•
04 Nov 2009
1 citations
"Effect of capillary tube on the per..." refers background in this paper
...Akash Deep Singh (2009) developed a mathematical model for adiabatic capillary tube....
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