An experimental study of the Effect of capillary tube diameter and configuration on the performance of a simple vapour compression refrigeration system (original) (raw)
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Effect of capillary tube on the performance of a simple vapour compression refrigeration system
IOSR Journal of Mechanical and Civil Engineering, 2014
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.
The study of the expansion device in simple vapor compression refrigeration system is necessary in order to understand the parameters which can enhance the overall performance of system. 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. The parameters stated above can be further optimized in order to enhance the performance of the refrigeration system. The present work is focused on the influence of tube diameter, tube length, coil pitch, and inlet condition on mass flow rate of refrigerant through helical coil capillary tube and also on investigation about the Coefficient of Performance (COP) of the system due to coiling effect of capillary tube. The use of helical capillary tube reduces the space for the refrigeration system which is the need for more compact refrigeration system in the current trend.
2019
A comprehensive review of the literature on the flow of different refrigerants through the capillary tubes of different geometries and different diameter viz. spiral, straight and helical coiled capillary tube, and 1.12mm, 1.4mm, 1.52mm diameter of capillary tube and R134a and mixture of R134a+hydrocarbon with 28:72 by mass refrigerant has been discussed in this paper. In this paper presents in chronological order the numerical and experimental investigations systematically under different condition. Flow aspects like mass flow rate C.O.P, pressure ratio through the capillary tube have been discussed. Furthermore, comparison of R134a and mixture of R134a + hydrocarbon have also been discussed. In this paper, we have found the best diameter for R134a and for the mixture, and we have also discussed the different geometry of the capillary tube. The paper provides key information about the range of input parameters viz. tube diameter, coil pitch and coil diameter, inlet pressure, and co...
IJRASET, 2021
The capillary tube is commonly employed in refrigerant flow control systems. As a result, the capillary tube's performance is optimal for good refrigerant flow. Many scholars concluded performance utilising experimental, theoretical, and analysis-based methods. This paper examines the flow analysis of a refrigerant within a capillary tube under adiabatic flow circumstances. For a given mass flow rate, the suggested model can predict flow characteristics in adiabatic capillary tubes. In the current work, R-134a refrigerant has been replaced by R600a refrigerant as a working fluid inside the capillary tube, and the capillary tube design has been modified by altering length and diameter, which were obtained from reputable literature. The analysis is carried out using the ANSYS CFX 16.2 software. The results show that utilising a small diameter and a long length (R-600a refrigerant flow) is superior to the present helical capillary tube. The most appropriate helical coiled design with a diameter of 0.8 mm and a length of 3 m is proposed.
The present review is concerned with the study of the effect of different expansion devices with refrigerant R22, R12, R407C, and R744 on the vapour compression refrigeration system. This paper is concerned with an overview of the project, the fundamental physics underlying the operation of fixed and variable expansion devices which includes capillary tube, thermostatic expansion valve, constant expansion device, Multi ejector expansion, and summarizes results of the analyses performed to compare them. For conducting the experimental verification with different expansion devices and R22, R12, R407C, R744 as refrigerant small test rig is used by many researchers. The experimental analysis conducted by various researchers for small capacity refrigeration systems are selected to study the performance characteristics of capacity of cooling, power required by the compressor, refrigerant mass flow rate and the coefficient of performance (COP) of the vapour compression refrigeration system with respect to different expansion devices like thermostatic expansion valve, Constant expansion valve and capillary tube.
The Effect of Capillary Tube Length & Diameter on Compressor Performance of Refrigeration System
African Journal of Advanced Pure and Applied Sciences (AJAPAS) , 2024
As the name suggests, the compressor is a device that compresses and raises the pressure of the refrigerant vapor coming from the evaporator, resulting in a saturation level that is higher than that of the chilled medium. As a result, the compressor needs to be powered by the actuator or main engine. The compressor can be referred to as a heat pump since it transfers heat from a low-temperature medium (the evaporator) to a high-temperature medium (the condenser). To determine how the capillary tube's width and length affected the compressor's performance in the refrigeration system, a basic refrigeration system was put together and used in this study. Three distinct lengths of capillary tubes were used, which are ((3m, 2m, 1m)) and two different diameters, which are (2.0mm, 2.2mm). Among the results obtained, the best performance coefficient and equivalent to the size of the compressor used were achieved when using the length ((1m)) and diameter ((2.0mm)) for the capillary tube, where the performance coefficient was ((6.8)).
A vapour compression refrigeration system uses a refrigerant which circulates in an airtight sealed circuit.. The refrigerant which circulated through the system, undergoes a number of changes in its state while passing through various components of the system. Each such change in the state of vapour is known as a process. The processes repeat in the same order of operation that forms a cycle. Performance of a simple vapour compression refrigeration cycle experiment was successfully carried out by incorporating the nozzle in the cycle. Additional pressure drop in the nozzle helped to achieve higher performance of the vapour compression refrigeration system. Graphs have been drawn to determine the variation of C.O.P with reduction in length of capillary. Has the nozzle angle increases from 10 0 to 14 0 , the COP increases and decreases thereafter. The 14 0 convergent angle nozzles are the optimum in getting higher COP of 3.61%. The refrigeration effect is increased by 7.16% and observed a reduction of 2.6% in compression work.
The behavior of performance parameters of a simple vapour compression refrigeration system were studied while its working under transient conditions occurred during cooling of a fixed mass of brine from initial room temperature to sub-zero refrigeration temperature. The effects of different lengths of capillary tube over these characteristics have also been investigated. It was concluded that with the constantly falling temperature over evaporator, refilling of it with more and more liquid refrigerant causes multifold increase in heat transfer coefficient which helps in maintaining refrigeration rate at falling temperature. Larger capillary tube decreases the tendency of refilling of evaporator but offers less 'evaporator temperature' effective in lower range of refrigeration temperature. Shorter capillary tube ensures higher COP initially but which deteriorates at a faster rate in lower temperature range. Capillary tube length must be optimized for maximum overall average COP of the system for the complete specified cooling job.
2010
In this work, the performance of alternative refrigerants in adiabatic capillary tube was investigated experimentally in a vapour compression refrigeration system. The mass flow rate was determined at a series of condensing temperatures, degree of sub-cooling and at various lengths of capillary tube. The average mass flow rate of R152a and R134a were 1.2 % lower and 1.9 % higher than that of R12 respectively, at the same operating conditions. The coefficient of performance (COP) obtained using R134a and R152a refrigerants were very close to that of R12 with only 2.6% and 1.3 % reduction respectively, while the COPs obtained using R23, R32 and R143a were significantly very low. The performance obtained in a refrigeration system differs among individual selected alternative refrigerants. The differences are larger for R143a, R32 and R23, and the deviation from the performance of R12 is in that order, while the differences are smaller or negligible for R134a and R152a. The best overall performance is obtained using R152a.
Materials Today: Proceedings, 2020
The primary role of expansion devices in Vapour Compression Refrigeration System (VCRS) are dropping the pressure, temperature and regulates the mass flow rate of refrigerant gas concerning with evaporator load conditions. Also, proper selection of expansion devices helps to control the degree of super heat to protect the compressor from liquid slugging. The performance of the vapour compression system partially depends on the expansion devices. The different predictions such as theoretical, experimental and simulation which are carried out by various researchers on basis of design, development and selection of the expansion devices concerning with different flow conditions. The present study is describes the performance of different expansion devices involving various refrigerants gases like as R134a, hydrocarbon LPG, R600a, and R22 etc. It is also discussed with proper understanding about the recent development of various expansion devices using for different refrigerant gases.