Free convection on a refrigerator’s condenser

Orzechowski, T.; Stokowiec, Katarzyna

doi:10.1051/epjconf/20146702089

Cited by 4 publications

(3 citation statements)

References 18 publications

(20 reference statements)

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“…The proposed MC design is extremely close in its characteristics to the design of air-cooled condensers with natural air circulation. The total heat transfer coefficients obtained in this study from the surface of a minichannel condenser are consistent with the data for air-cooled condensers [26]. The total heat transfer coefficient MC of the proposed design in the limiting case at night could theoretically reach 17.6 W•m -2 •°С -1 at a temperature difference of 15 °С.…”

Section: Comparison Of Characteristics Of Mini-channel Condenser and ...supporting

confidence: 86%

Condensation heat removal due to the combined impact of natural convection and radiative cooling

Tsoy

Granovskiy

Nurakhmetov

et al. 2023

EEJET

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The work examines the heat exchange characteristics of a condenser in which heat removal of the refrigerant condensation occurs due to natural convection and radiation cooling. The heat exchanger is designed to reduce energy costs for the removal of condensation heat. Unlike traditional air cooling condensers, it uses radiation cooling, a method of heat removal based on its transmission in the form of infrared radiation through the planet’s atmosphere into the surrounding outer space. A method for calculating the thickness of the radiating plate has been developed. To minimize material consumption and cost, the distance between the tubes is reduced to 40 mm, and the thickness of the aluminum radiating plate is reduced to 0.32 mm. The inner diameter of the coolant channels is 1 mm. For the experimental study of the condenser, an experimental stand working on R134a refrigerant was developed. Theoretical and experimental studies of heat transfer have been carried out. The heat transfer coefficient of the heat exchanger, reduced to the area of the radiating surface, was from 10.3±1.36 to 18.7±2.47 W·m–2·°C–1, when the condensation temperature was 12.8...21.9 °С higher than the temperature of atmospheric air. The operability of the condenser is shown both during the day and at night, in the presence of precipitation in the form of rain and snow, and a high level of cloudiness. The material capacity and filling of the refrigerant in the condenser are comparable to the characteristics of air-cooled condensers with forced air circulation. At the same time, it does not consume electricity. It can be used in stationary refrigeration systems (in data processing centers, commercial refrigeration equipment, air conditioners) to increase their energy efficiency

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Section: Comparison Of Characteristics Of Mini-channel Condenser and ...supporting

confidence: 86%

Condensation heat removal due to the combined impact of natural convection and radiative cooling

Tsoy

Granovskiy

Nurakhmetov

et al. 2023

EEJET

View full text Add to dashboard Cite

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“…In order to select the PCM suitable for the required system it is necessary to learn the thermal features of the substance chosen such as heat capacity, phase change heat and melting temperature [10]. Phase change materials are diverse.…”

Section: Introductionmentioning

confidence: 99%

Quasi-stationary phase change heat transfer on a fin

Orzechowski

Stokowiec

2016

EPJ Web of Conferences

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Abstract. The paper presents heat transfer research basing on a long fin with a circular cross-section. Its basis is welded to the pipe where the hot liquid paraffin, having a temperature of 70oC at the inflow, is pumped. The analyzed element is a recurrent part of a refrigeration's condenser, which is immersed in a paraffin. The temperature of the inflowing liquid is higher than the temperature of the melting process for paraffin, which allows the paraffin to liquify. The temperature at the basis of the rib changes and it is assumed that the heat transfer is quasi-stationary. On this basis the estimation of the mean value of heat transfer coefficient was conducted. The unsteady thermal field of the investigated system was registered with an infrared camera V50 produced by a Polish company Vigo System. This device is equipped with a microbolometric detector with 384 × 288 elements and the single pixel size 25 × 25 ȝm. Their thermal resolution is lower than 70 mK at a temperature of 30 o C. The camera operates at 7,5 ÷ 14 μm long-wave infrared radiation range. For a typical lens 35 mm the special resolution is 0.7 mrad. The result of the calculations is mean heat transfer coefficient for the considered time series. It is equal to 50 W m -2 K -1 and 47 W m -2 K -1 on the left and right side of the fin, respectively. The distance between the experimental data and the curve approximating the temperature distribution was assessed with the standard deviation, Sd = 0.04 K.

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“…They are installed directly beneath the road surface to maintain a constant, positive temperature of asphalt. Such solutions take advantage of geothermal energy available throughout the year [11], which can be accumulated to cover the peak demand [12].…”

Section: Introductionmentioning

confidence: 99%

Passive heating of the ground surface

Tyburczyk

2016

EPJ Web of Conferences

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Abstract. The phenomenon of phase change is one of the most important contemporary issues of thermal engineering. In particular, this applies to all kinds of heat exchanger systems, which should achieve the highest possible efficiency while reducing investment and operating costs. Some of these systems are heat pipes or thermosyphons, which, among others, are used for the heat transfer, temperature stabilization and the regulation of heat flux density. Additionally, they are passive systems, and therefore do not require an external power supply. Heat pipes can be used to stabilize the surface temperature of roads and driveways. Large heat tubes can be applied for heating the surface of bridges and overpasses, which become icy in unfavorable climatic conditions. The paper presents research on the test facility, whose main component is a long vertical copper fin. The temperature at the base of the fin was kept constant for a given series of measurements. Heat receiving fluid was ethanol at atmospheric pressure. The measurement methodology and the results of investigations were discussed. The surface temperature distribution was measured with the infrared camera, and on this basis the local values of heat flow and the heat transfer coefficient were determined. The results were presented as boiling curves for both the fin with the smooth surface and the one covered with a metal capillary-porous structure. The results obtained are useful in the design of heat exchangers, including passive heating of the ground.

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Free convection on a refrigerator’s condenser

Cited by 4 publications

References 18 publications

Condensation heat removal due to the combined impact of natural convection and radiative cooling

Condensation heat removal due to the combined impact of natural convection and radiative cooling

Quasi-stationary phase change heat transfer on a fin

Passive heating of the ground surface

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