Experimental Investigation of Compact Evaporators for Ultralow Temperature Refrigeration of Microprocessors

Wadell, Robert P.; Joshi, Yogendra; Fedorov, Andrei G.

doi:10.1115/1.2753919

Cited by 9 publications

(5 citation statements)

References 20 publications

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“…Wadell (2005) yüksek lisans tezinde yüksek sıcaklık çevriminde R134a, düşük sıcaklık çevriminde R508B olacak şekilde tasarlanan iki kademeli bir soğutma sistemi üzerinde çalışmıştır. Sistemin R508B buharlaştırıcısına buharlaşma sıcaklığı -86°C ve -79°C; kütlesel debisi (0.833-1.167)x10-3 kg/s olacak şekilde akışkan göndermiş ve sonuçları incelemiştir.…”

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Numerical Investigation of The Effects of Subcooling and Superheating on The System Performance of a Two Stage Refrigeration System Working in Ultra Low Temperatures

Yılmaz¹,

Sınar²,

Özyurt³

et al. 2017

AKU-J. Sci. Eng.

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Soğutma sistemleri çalışılmak istenen soğutma sıcaklığına bağlı olarak çeşitli kategorilere ayrılmaktadır.-50°C ve-100°C sıcaklık aralığında gerçekleştirilen soğutma işlemleri ultra düşük sıcaklık uygulaması sınıfına girmektedir. Soğutma sistemleri; kompresör sıkıştırma oranı, dış hava sıcaklıkları ve kullanılan akışkan özellikleriyle sınırlandırıldığından dolayı bu sıcaklık değerlerini tek kademeli bir soğutma sistemiyle elde edebilmek çok zordur. Bu sebeple iki kademeli soğutma sistemleri kullanılmaktadır. Bu sistemlerin yüksek sıcaklık çevrimlerinde R134a, R404A ve R507A gibi akışkanlar; düşük sıcaklık çevriminde ise R23, R503 ve R508B gibi akışkanlar kullanılabilmektedir. Bu çalışmada, yüksek sıcaklık çevriminde R404A; düşük sıcaklık çevriminde ise R508B akışkanının kullanıldığı iki kademeli bir soğutma sistemi termodinamik olarak incelenmiştir. EES (Engineering Equation Solver) yazılımı kullanılarak ultra düşük oda sıcaklıklarında çalışan bir soğutma sistemine ait ekipmanların enerji ve ekserji analizi yapılmış ve sonuçlar irdelenmiştir. Gerçekleştirilen çalışmada kaskat ısı değiştiricisindeki buharlaşma sıcaklığının artışı sistem performansını arttırmakta kaskat ısı değiştiricisindeki sıcaklık farkının artışının ise performans değerini azalttığı görülmüştür. Sistem performansının ise-30 o C ile-35 o C arasındaki kaskat ısı değiştirici buharlaşma sıcaklığında azami değerine ulaştığı sonucuna varılmıştır.

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Numerical Investigation of The Effects of Subcooling and Superheating on The System Performance of a Two Stage Refrigeration System Working in Ultra Low Temperatures

Yılmaz¹,

Sınar²,

Özyurt³

et al. 2017

AKU-J. Sci. Eng.

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“…Various refrigeration cooling schemes have been suggested to achieve this objective [2], [3]. Of those, vapor compression systems have attracted the most attention because of their relatively high cooling capacity at temperature of interest [4]- [7].…”

Section: A Application Of Refrigeration Coolingmentioning

confidence: 99%

Low-Temperature Two-Phase Microchannel Cooling for High-Heat-Flux Thermal Management of Defense Electronics

Lee¹,

Mudawar²

2009

IEEE Trans. Comp. Packag. Technol.

138

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For a given heat sink thermal resistance and ambient temperature, the temperature of an electronic device rises fairly linearly with increasing device heat flux. This relationship is especially problematic for defense electronics, where heat dissipation is projected to exceed 1000 W cm 2 in the near future. Direct and indirect low-temperature refrigeration cooling facilitate appreciable reduction in the temperature of both coolant and device. This paper explores the benefits of cooling the device using direct and indirect refrigeration cooling systems. In the direct cooling system, a microchannel heat sink serves as an evaporator in a conventional vapor compression cycle using R134a as working fluid. In the indirect cooling system, HFE 7100 is used to cool the heat sink in a primary pumped liquid loop that rejects heat to a secondary refrigeration loop. Two drastically different flow behaviors are observed in these systems. Because of compressor performance constraints, mostly high void fraction two-phase patterns are encountered in the R134a system, dominated by saturated boiling. On the other hand, the indirect refrigeration cooling system facilitates highly subcooled boiling inside the heat sink. Both systems are shown to provide important cooling benefits, but the indirect cooling system is far more effective at dissipating high heat fluxes. Tests with this system yielded cooling heat fluxes as high as 840 W cm 2 without incurring critical heat flux (CHF). Results from both systems are combined to construct an overall map of performance trends relative to mass velocity, subcooling, pressure, and surface tension. Extreme conditions of near-saturated flow, low mass velocity, and low pressure produce "micro" behavior, where macrochannel flow pattern maps simply fail to apply, instabilities are prominent, and CHF is quite low. One the other hand, systems with high mass velocity, high subcooling, and high pressure are far more stable and yield very high CHF values; two-phase flow in these systems follows the fluid flow and heat transfer behavior as well as the flow pattern maps of macrochannels.Index Terms-Electronics cooling, high heat flux, microchannel flow, phase change. NOMENCLATUREAspect ratio of microchannel. Boiling number. Specific heat.

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“…One of the main objectives sought with this type of system is reaching lower evaporation temperatures than single-stage systems. In this sense, Coggins [66], based on previous work by Wadell [67], developed a two-stage cascade refrigeration system using R508B and R404A for cooling of high-performance microprocessors; however, the system was relatively large at 60,000 cm 3 . It was found that the cooling capacity of the system was 40 W, sufficient to maintain the chip at −61 • C.…”

Section: Modifications To the Basic Vapor Compression Cyclementioning

confidence: 99%

A Review of Small-Scale Vapor Compression Refrigeration Technologies

Silva-Romero,

Belman-Flores,

Aceves

2024

Applied Sciences

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The study and development of miniature refrigeration and climate conditioning systems based on vapor compression for small-scale applications have received wide interest in recent years due to their advantages compared with other available technologies, both active and passive. This paper identifies different applications and areas of opportunity, including electronic components and personal cooling, where small-scale vapor compression refrigeration systems are anticipated to play a key role in technological development. This paper presents the current state of the art, including applications, component designs, operating conditions, experiments, published results, etc. to describe the current status of small-scale vapor compression refrigeration and illustrate a perspective for the future of this technology.

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Experimental Investigation of Compact Evaporators for Ultralow Temperature Refrigeration of Microprocessors

Cited by 9 publications

References 20 publications

Numerical Investigation of The Effects of Subcooling and Superheating on The System Performance of a Two Stage Refrigeration System Working in Ultra Low Temperatures

Numerical Investigation of The Effects of Subcooling and Superheating on The System Performance of a Two Stage Refrigeration System Working in Ultra Low Temperatures

Low-Temperature Two-Phase Microchannel Cooling for High-Heat-Flux Thermal Management of Defense Electronics

A Review of Small-Scale Vapor Compression Refrigeration Technologies

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