Comparison of parallel- and counter-flow circuiting in an industrial evaporator under frosting conditions

Aljuwayhel, Nawaf F.; Reindl, Douglas T.; Klein, S.A.; Nellis, Gregory

doi:10.1016/j.ijrefrig.2007.04.009

Cited by 13 publications

(7 citation statements)

References 4 publications

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“…They distinguished three stages in frost build up, which they related to the capacity and COP of the heat pump. They found that performance declined rapidly in the third stage during which a fluffy frost layer was formed, particularly when the outdoor temperature was near 0 o C. Last but not least is the work reported by (Aljuwayhel et al, 2008) about frost build up on a real size evaporator in an industrial refrigeration ammonia system operating below -34 o C. In-situ measurements of temperatures, flow rates and humidity were gathered to assess capacity degradation as a result of frost. Capacity losses as high as 26%, were recorded after 42 hours of operation.…”

Section: Methodsmentioning

confidence: 99%

Numerical Modeling and Experimentation on Evaporator Coils for Refrigeration in Dry and Frosting Operational Conditions

Aidoun¹,

Ouzzane²,

Bendaoud³

2011

Two Phase Flow, Phase Change and Numerical Modeling

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Section: Methodsmentioning

confidence: 99%

Numerical Modeling and Experimentation on Evaporator Coils for Refrigeration in Dry and Frosting Operational Conditions

Aidoun¹,

Ouzzane²,

Bendaoud³

2011

Two Phase Flow, Phase Change and Numerical Modeling

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“…For the presented work, Eq. 1a, proposed by Aljuwayhel (Aljuwayhel et al, 2007), was used as starting point to measure frost growth. The author considered frost growth as a continuous process; hence, this work accounts for relative humidity only during the time, both, compressor and evaporator fan are on.…”

Section: Frost Modellingmentioning

confidence: 99%

Experimental assessment and semi empirical estimation of frost accretion—A case study on a spine-finned inverted-V tube array evaporator

Carvajal-Mariscal

León-Ruiz²,

Belman-Flores³

et al. 2023

Front. Mech. Eng.

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Present work focuses on frost accretion in a spine-finned inverted-V tube array evaporator. An experimental evaluation was performed using a standard issue, vertical top-mount, 18 cubic feet, 0.5 m3, refrigerator. Evaporator temperature distribution, inner airflow velocity, and relative humidity were measured to account for convective phenomena influencing frost distribution. Frost formation and accretion on the surface of the evaporator were visualized using thermal and microscopic imagery. The images were processed using a machine vision algorithm to measure frost thickness. Complementarily, frost density and vapor mass transfer were computed using available correlations. An estimation function was derived from the compiled data using a semi empirical approach, i.e., direct measurements and thermophysical substance properties. The resulting mathematical expression estimated the frost accretion rate within an error expectancy, RMSE, of 0.1479 and displayed a goodness-of-fit, R-Squared, of 0.9029. Based on these results, semi empirical estimation, is proposed as a viable approach to construct adequate limits for new predictions, vis-à-vis evaporator performance, ultimately reducing appliance energy consumption via implementing more effective control strategies regarding internal defrosting.

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“…However, this geometry modification may be difficult to realize without adding substantial complexity in manufacturing process. (Aljuwayhel et al, 2007) developed a heat exchanger frost accumulation model to simulate the performance of counter-flow and parallel-flow circuitry evaporators under frosting conditions. They validated the model by testing the counter-flow circuitry evaporator.…”

Section: Introductionmentioning

confidence: 99%

Tube-fin Heat Exchanger Circuitry Optimization For Improved Performance Under Frosting Conditions

Qiao

Aute

2019

Linköping Electronic Conference Proceedings

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Frost accumulation on tube-fin heat exchanger leads to reduction in evaporator capacity and deteriorates cycle efficiency. The conventional counter-flow heat exchanger circuitry has the disadvantage that more frost tends to accumulate in the first few banks exposed to the incoming air. This frost concentration makes the air side flow resistance increase rapidly, thus reduces the air flow rate and evaporator capacity under constant fan power. In this paper, a novel integer permutation based Genetic Algorithm is used to obtain optimal circuitry design with improved HX performance under frosting conditions. A dynamic HX model with the capability to account for non-uniform frost growth on a fan-supplied coil is used to assess the performance of optimal circuitry. The case study shows that the proposed circuitry design approach yields better circuitry with larger HX capacity, more uniform frost distribution, less air flow path blockage, and therefore longer evaporator operation time between defrost operations.

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Comparison of parallel- and counter-flow circuiting in an industrial evaporator under frosting conditions

Cited by 13 publications

References 4 publications

Numerical Modeling and Experimentation on Evaporator Coils for Refrigeration in Dry and Frosting Operational Conditions

Numerical Modeling and Experimentation on Evaporator Coils for Refrigeration in Dry and Frosting Operational Conditions

Experimental assessment and semi empirical estimation of frost accretion—A case study on a spine-finned inverted-V tube array evaporator

Tube-fin Heat Exchanger Circuitry Optimization For Improved Performance Under Frosting Conditions

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