Simulation of the Effects of a Non-Adiabatic Capillary Tube on Refrigeration Cycle
01 Jan 2008-
Abstract: The simulation of refrigeration cycle is important since the experimental approach is too costly and time-consuming. The present simulation focuses on the effect of capillary tube-suction line heat exchangers (CT-SLHX), which are widely used in small vapor compression refrigeration systems. The simulation of steady states is based on fundamental conservation equations of mass and energy. These equations are solved simultaneously through iterative process. The non-adiabatic capillary tube model is based on homogeneous two-phase model. This model is used to understand the refrigerant flow behavior inside the non-adiabatic capillary tubes. The simulation results show that both of the location and length of heat exchange section influence the coefficient of performance (COP). These results can be used in either design calculation of capillary tube length for refrigeration cycle or effect of suction line heat exchanging on refrigeration cycle.
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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.
5 citations
Cites methods from "Simulation of the Effects of a Non-..."
...Sanggoon Park et al. (2008) simulated the effects of a non adiabatic capillary tube on refrigeration cycle....
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TL;DR: In this paper, a homogenous mathematical model to simulate capillary tube-suction line heat exchanger (CT-SL HX) based on the fundamentals of conservations of mass, momentum and energy was developed.
Abstract: The present research is to develop a homogenous mathematical model to simulate capillary tube-suction line heat exchanger (CT-SL HX) based on the fundamentals of conservations of mass, momentum and...
4 citations
Cites background from "Simulation of the Effects of a Non-..."
...Consequently, a higher cooling capacity is expected and a higher coefficient of performance (COP) is anticipated [3], [4]....
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TL;DR: In this paper, a variable temperature insert has been developed in-house as a cryogenic thermometer calibration facility, which includes a temperature sensor and wires heat-intercept in the 2.2 K-325 K temperature range.
Abstract: A prototype of a variable temperature insert has been developed in-house as a cryogenic thermometer calibration facility. It was commissioned in fulfilment of the very stringent requirements of the temperature control of the cryogenic system. The calibration facility is designed for calibrating industrial cryogenic thermometers that include a temperature sensor and the wires heat-intercept in the 2.2 K–325 K temperature range. The isothermal section of the calibration block onto which the thermometers are mounted is weakly linked with the temperature control zone mounted with cooling capillary coil and cryogenic heater. The connecting wires of the thermometer are thermally anchored with the support of the temperature insert. The calibration procedure begins once the temperature of the support is stabilized. Homogeneity of the calibration block's temperature is established both by simulation and by cross-comparison of two calibrated sensors. The absolute uncertainty present in temperature measurement is calculated and found comparable with the measured uncertainty at different temperature points. Measured data is presented in comparison to the standard thermometers at fixed points and it is possible to infer that the absolute accuracy achieved is better than ±0.5% of the reading in comparison to the fixed point temperature. The design and development of simpler, low cost equipment, and approach to analysis of the calibration results are discussed further in this paper, so that it can be easily devised by other researchers.
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References
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26 Dec 1962
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1,433 citations
TL;DR: In this paper, the authors derived analytical expressions for bubble radii and growth rates in an analysis of surface boiling at high heat transfer rates and showed that the product of bubble radius and radial velocity is a constant.
Abstract: Analytical expressions for bubble radii and growth rates derived by the authors are applied in an analysis of surface boiling at high heat transfer rates. It is shown that the product of bubble radius and radial velocity is a constant, independent of the bubble radius. This circumstance permits the formulation of a Reynolds number for the flow in the thin superheated liquid layer adjacent to the heating surface. The result of the analysis is then applied to maximal heat transfer rates in pool boiling.
559 citations
TL;DR: In this article, a model for the prediction of the local frictional pressure drop of two-phase flows during vaporization of R-12 in capillary tubes is presented, with a relative error of about 15%.
Abstract: The local frictional pressure drop during vaporization of R-12 along capillary tubes is experimentally investigated. A model for the prediction of the local frictional pressure drop of two-phase flows during vaporization of R-12 in capillary tubes is presented. This model agrees with the experimental data to within a relative error of about 15%.
320 citations