Designing a mesoscale vapor-compression refrigerator for cooling high-power microelectronics

Abstract

A mesoscale vapor-compression refrigerator is defined here as one that is -5 cm or smller in size. Such a refrigerator could then be integrated in high-power microelectronics packaging, and thus offer a new cooling solution. To begin the process of designing such a small-scale vapor-compression refrigerator, a comparison of three different refrigerants was carried out, revealing that ammonia ("3) leads to the most efficient refrigerator. From there, a review and discussion of five types of compressors shows that a scroll compressor appears to be the most promising candidate for miniaturizing down to the -5 cm size. This information was used to design three realistic vapor-compression refrigerators-for heat loads of 100, 200, and 300W-using commercially-available scroll compressors and easily -fabricated heat exchangers.These design calculations demonstrate that, for a 100-W vapor-compression refrigerator, an air-cooled condenser can be made as small as almost 5 cm on a side, but that the compressor is still about 15 cm in its maximum dimensions. Thus, it is suggested that future research work concentrate on miniaturizing the compressor, to allow the entire system to tit within the -5 cm size limit.

Experimental Investigation of a Miniature-Scale Refrigeration System for Electronics Cooling

“…A mesoscale vapor-compression refrigerator was analyzed in Phelan and Swanson [8], with the term mesoscale denoting a system of 5 cm 3 in total volume or smaller. Different refrigerants were considered in an effort to maximize the COP.…”

“…A miniature-scale refrigeration system [8], with the term miniature-scale denoting a system in which the heat exchangers have a maximum height of 45 mm (1-U rack) and the compressor has a maximum volume of 1000 cm 3 , has been designed, constructed and tested. The components of the miniature-scale refrigeration system were prototyped and/or selected from commercially available components to fit into the space available in a personal computer.…”

Review and Comparative Analysis of Studies on Saturated Flow Boiling in Small Channels

“…In particular, as will be evident from the detailed review of the literature presented here, very limited attention has been directed towards details of the influence of thermodynamic vapor quality on the heat transfer coefficient in microchannels. Knowledge of the flow boiling heat transfer coefficient as a function of vapor quality is essential in applications such as vapor compression-based refrigeration, which has been shown to be an effective means for cooling electronics [21][22][23]. All of the refrigerant liquid stream goes through a change of phase to the vapor state in such systems.…”

Refrigerant flow boiling heat transfer in parallel microchannels as a function of local vapor quality

“…In contrast, refrigeration with vapor compression systems [12,13,14] has received less attention even though it has been shown to be an effective means for lowering the coolant temperature, and therefore, maintaining acceptable device temperatures when dissipating high heat fluxes. The primary advantages of small-scale vapor compression systems are the possibility of achieving fluid temperatures below ambient, a lower freezing point compared to water, and compatibility with electronic circuits in case of leakage due to their higher dielectric strength.…”