• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.255-262
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• 2008

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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.3
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• pp.131-139
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• 2009

The simulation of refrigeration cycle is important since the experimental approach is costly and time-consuming. The present paper focuses on the simulation of a refrigeration cycle equipped with a capillary tube-suction line heat exchanger(SLHX), which is widely used in small vapor compression refrigeration systems. The present simulation is based on fundamental conservation equations of mass, momentum, and energy. These equations are solved through an iterative process. The non-adiabatic capillary tube model is based on homogeneous two-phase flow model. This model is used to understand the refrigerant flow behavior inside the non-adiabatic capillary tube. The simulation results show that both of the location and length of heat exchange section influence the coefficient of performance (COP).

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.8
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• pp.1144-1151
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• 2009

Refrigeration systems can be incorporated with non-adiabatic capillary tubes to improve their efficiency. The non-adiabatic capillary tube is constructed by joining the capillary tube with suction pipe to allow heat transfer between them, which is called capillary tube-suction line heat exchanger(SLHX). There are various joining methods and they may influence the characteristics of the refrigeration cycle. The present work aims to analyze the effect of widely-used two joining methods on the refrigeration cycle. The results show that soldered SLHX has much less thermal resistance than tapered SLHX but slightly outperforms in terms of coefficient of performance(COP) and cooling capacity. The soldered SLHX increased COP and cooling capacity of a refrigerator by 5.09% and 14.77% while the tapered SLHX did by 5.05% and 14.75%, respectively.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.263-270
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• 2008

The capillary tube/suction line heat exchanger (SLHX) is widely used in small refrigeration systems. The refrigerant flowing in the SLHX experiences frictional and accelerational head losses, flashing, and heat transfer simultaneously. The simulation of refrigerant flow through SLHX is important since this will help engineers analyze and optimize the SLHX incorporated in a refrigeration system. The present SLHX model is based on conservation equations of mass, momentum and energy. Also a meta-stable model is included. All these equations are solved simultaneously. In this paper, HFC-134a refrigerant flow through a non-adiabatic capillary tube is simulated. The simulation results are discussed but not validated against experimental measurements yet.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.550-555
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• 2009

The present simulation focuses on the effect of the shape of capillary tube-suction line heat exchangers(SLHX), The results in the three cases of the SLHX types show that both of the location and length of heat exchange section influence the coefficient of performance(COP) and cooling capacity. Simulation shows the COP may be improved by 4.6% and the cooling capacity may be improved by 13.6% in the Lateral type.

• Journal of Mechanical Science and Technology
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• v.17 no.10
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• pp.1507-1519
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• 2003

The two-phase flow patterns for both non-loop and loop type oscillating capillary tube heat pipes (OCHPs) were presented in this study. The detailed flow patterns were recorded by a high-speed digital camera for each experimental condition to understand exactly the operation mechanism of the OCHP. The design and operation conditions of the OCHP such as turn number, working fluid, and heat flux were varied. The experimental results showed that the representative flow pattern in the evaporating section of the OCHP was the oscillation of liquid slugs and vapor plugs based on the generation and growth of bubbles by nucleate boiling. As the oscillation of liquid slugs and vapor plugs was very speedy, the flow pattern changed from the capillary slug flow to a pseudo slug flow near the annular flow. The flow of short vapor-liquid slug-train units was the flow pattern in the adiabatic section. In the condensing section, it was the oscillation of liquid slugs and vapor plugs and the circulation of working fluid. The oscillation flow in the loop type OCHP was more active than that in the non-loop type OCHP due to the circulation of working fluid in the OCHP. When the turn number of the OCHP was increased, the oscillation and circulation of working fluid was more active as well as forming the oscillation wave of long liquid slugs and vapor plugs in the OCHP. The oscillation flow of R-142b as the working fluid was more active than that of ethanol and the high efficiency of the heat transfer performance of R -142b was achieved.