Comparative investigations of the condensation of R134a and R404A refrigerants in pipe minichannels

Bohdal, T.; Charun, H.; Sikora, Małgorzata

doi:10.1016/j.ijheatmasstransfer.2011.01.005

Cited by 157 publications

(44 citation statements)

References 32 publications

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“…For the same valueṁ = const flowing to the multiport, value of the average heat transfer coefficient, α a , is growing when the process takes place in a single minichannel, and for multiport MULTI-4 is also higher than for the MULTI-8. It is interesting to compare the characteristics of condensation process obtained according to the type of a refrigerant [7]. Figures 9 and 10 show a example characteristics for MULTI-4 and MULTI-8.…”

Section: Analysis Of Experimental Resultsmentioning

confidence: 99%

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Condensation of refrigerant R407C in multiport minichannel section

Bohdal¹,

Charun²,

Sikora³

2016

Archives of Thermodynamics

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Analysis of the state of-the-art in research of refrigerant condensation in miniature heat exchangers, so-called multiports, was made. Results of refrigerant R407C condensation in a mini condenser made in the form of two bundles of tubular minichannels from stainless steel with an inside diameter 0.64 mm and length 100 mm have been presented. Two exchangers consisted of four minichannels and 8 minichannels have been investigated. The values of average heat transfer coefficient and frictional pressure drops throughout the condensation process were designated. The impact of the vapor quality of refrigerant and the mass flux density on the intensity of heat transfer and flow resistance were illustrated. A comparative analysis of test results for various refrigerants in both mini heat exchangers were made.

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Section: Analysis Of Experimental Resultsmentioning

confidence: 99%

“…2, and external appearance in Fig.3 [6,7]. The basic element of the test stand was a operating distance (1), along with the testing mini heat exchanger.…”

Section: Testing Facilitymentioning

confidence: 99%

Condensation of refrigerant R407C in multiport minichannel section

Bohdal¹,

Charun²,

Sikora³

2016

Archives of Thermodynamics

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“…al. [22] correlation and haraguchi et al [23] Table 2 shows mean deviation and accuracy of the nine correlations for the condensation Table 1. Experimental data sources for condensation heat transfer Table 2.…”

Section: Comparative Study Of Chtc For Film Condensationmentioning

confidence: 99%

A Comparative Study of Refrigerant Side Condensing Heat Transfer Coefficient for Horizontal Mini Channel

Parekh

Patel

Tailor

2018

MATEC Web of Conferences

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Abstract. Heat exchanger developments are driven by increase in energetic efficiency and emission reduction. To reach the required standards, new systems are required based on mini-channels along with macro channels also. Mini-channels can be described as tubes with one or more ports extruded in aluminium or any other material like copper, steel etc. with hydraulic diameter in the range of 0.2 to 3 mm. Its use in refrigeration systems became a reality; thanks to the human ability to make micro-scale systems. Some heat exchanger enterprises have some models developed specially for their use in automotive sector, cooling sector and industrial refrigeration without having knowledge of how these reduced geometries affect the most important parameters such as pressure drop and the heat transfer coefficient. To overcome this, an exhaustive literature review of the last two decades has been performed to determinate the state of the research. Among all the publications, several models have been reviewed to check the predicting capacities of them as most of them were developed for macro channels along with single port mini-channel tubes. This work presents a comparative study of existing heat transfer correlations for horizontal flow through mini-channels. Present work total 317 experimental results of condensation heat transfer coefficient obtained from several published literatures and also various condensation heat transfer correlations are reviewed for horizontal flow through mini-channels. Results of condensation heat transfer coefficient obtained for various correlations are compared with the experimental results. Among all correlations used the Bohdalet's correlation gives value of condensation heat transfer coefficient closer to experimental results and has a mean relative deviation (MRD) of 5.4 % whereas mean absolute relative deviation (MARD) of 20.72%.Hence in present work the effort has been made to find better model to predict the condensation heat transfer coefficient which can fit the experimental data with least MRD and MARD.

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“…As can be seem from (3) the friction factors in two phase flow are summed up in a geometrical manner. The first term on the right hand side of (3) can be determined from the definition of the twophase flow multiplier (1). Pressure drop in the two-phase flow without bubble generation can also be considered as a pressure drop in the equivalent flow of a fluid flowing with velocity w TP.…”

Section: Dissipation Based Model For Pressure Drop Calculationsmentioning

confidence: 99%

Pressure Drop of HFE7000 and HFE7100 in Flow Condensation in Minichannels With Account of Non-Adiabatic Effects

Mikielewicz

Andrzejczyk

Mikielewicz

2014

MATEC Web of Conferences

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Abstract. Flow boiling and flow condensation are often regarded as two opposite or symmetrical phenomena involving the change of phase. There is a temptation to describe both these phenomena with one only correlation. From amongst the structures present in flow boiling and flow condensation at least the annular flow structure seems to be mostly appropriate to the common modeling. However, the shear stress acting between vapor phase and liquid phase is not the same in the respective cases, i.e. flow boiling and flow condensation. Most of modeling of heat transfer in case of condensation inside channels relates the heat transfer coefficient to the friction coefficient. All existing approaches are either the empirical fits to experimental data or form an attempt to combine two major influences to heat transfer, namely the convective flow boiling without bubble generation and nucleate boiling. In the paper the authors present investigations of flow condensation with the use of the HFE7100 and HFE 7000 as a working fluids and their own condensation model inside tubes with account of non-adiabatic effects. The model will be confronted with own data for a new fluid HFE7000 and HFE 7100.

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Comparative investigations of the condensation of R134a and R404A refrigerants in pipe minichannels

Cited by 157 publications

References 32 publications

Condensation of refrigerant R407C in multiport minichannel section

Condensation of refrigerant R407C in multiport minichannel section

A Comparative Study of Refrigerant Side Condensing Heat Transfer Coefficient for Horizontal Mini Channel

Pressure Drop of HFE7000 and HFE7100 in Flow Condensation in Minichannels With Account of Non-Adiabatic Effects

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