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Collin Coolidge

Bio: Collin Coolidge is an academic researcher from University of Colorado Boulder. The author has contributed to research in topics: Gas compressor & Heat spreader. The author has an hindex of 4, co-authored 6 publications receiving 59 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors developed flexible thermal ground planes (TGPs) with an ultra-thin thickness of 0.5 mm using copper-cladded polyimide as the encasing material, woven copper mesh as a wick, and electroplated copper pillars to support a vapor core.
Abstract: Thermal ground planes (TGPs) are passive thermal management devices that utilize the latent heat associated with phase change to achieve high effective thermal conductance, similar to heat pipes. In this paper, we develop flexible TGPs with an ultra-thin thickness of 0.5 mm using copper-cladded polyimide as the encasing material, woven copper mesh as a wick, and electroplated copper pillars to support a vapor core. The lowest thermal resistance of one TGP is characterized to be only 1/3 that of an equivalently sized copper heat spreader. The effects of size scaling of evaporator and condenser, and overall TGP sizes on the thermal resistances of TGPs are experimentally characterized. A simple series thermal resistance model, which accounts for vapor core thermal resistance, is developed to predict the measured results. This experimentally validated model can be used for the design of TGPs with varying sizes of evaporator and condenser, and overall size. [2015-0032]

50 citations

Journal ArticleDOI
TL;DR: In this article, a micro gas compressor is constructed by MEMS-based check valves coupled to a Kapton membrane driven by a mechanically amplified piezoelectric actuator.
Abstract: This study describes the fabrication, assembly, and testing of a micro gas compressor. The compressor is formed by MEMS-based check valves coupled to a Kapton membrane driven by a mechanically amplified piezoelectric actuator. The valves are surface machined on a silicon substrate using polyimide as the structural material and copper as the sacrificial material. This design allows valves with low leak rates, low compressor dead volume, and the high compressible volume required to generate the pressure levels required of numerous applications including cryogenic cooling. The assembled compressor is tested with voltages over the range of 25–180 V and frequencies over the range of 25–700 Hz. A maximum pressure ratio of 4.3:1 is found when the actuator provides a maximum displacement of 156 μm, while the maximum flow-rate through the compressor of 51 standard cubic cm per minute (sccm) is observed when the compressor is operating at its resonant frequency.

11 citations

Patent
17 Sep 2015
TL;DR: In this paper, a thermal ground plane (TGP) is defined, and a TGP may include a first planar substrate member configured to enclose a working fluid, a second planar sub-surface member configured for enclosing the working fluid; a plurality of wicking structures disposed on the first substrate; and one or more planar spacers on the second sub-sub-surface.
Abstract: A thermal ground plane (TGP) is disclosed. A TGP may include a first planar substrate member configured to enclose a working fluid; a second planar substrate member configured to enclose the working fluid; a plurality of wicking structures disposed on the first planar substrate; and one or more planar spacers disposed on the second planar substrate. The first planar substrate and the second planar substrate are may be hermetically sealed.

8 citations

Patent
14 Sep 2015
TL;DR: In this article, the authors described a heat spreader with a first layer having a thickness less than about 300 microns, a plurality of pillars disposed on the first layer and arrayed in a pattern, where each of the plurality had a height of less than 100 microns.
Abstract: Embodiments described in this disclosure include a heat spreader. The heat spreader may include a first layer having a thickness less than about 300 microns; a plurality of pillars disposed on the first layer and arrayed in a pattern, wherein each of the plurality of pillars have a height of less than 100 microns; a second layer having a thickness of less than 200 microns, wherein a portion of the first layer and a portion of the second layer are sealed together; and a vacuum chamber formed between the first layer and the second layer and within which the plurality of pillars are disposed.

7 citations

Proceedings ArticleDOI
16 Jul 2013
TL;DR: In this paper, a micro-compressor was developed which uses MEMS-based check valves coupled to a membrane, which is actuated with a mechanically amplified piezoelectric amplifier.
Abstract: A number of small electronic devices benefit from micro-scale low temperature operation. Recently we have developed micro cryogenic coolers (MCCs) using a low-pressure, mixed-refrigerant Joule-Thomson cycle. The cryocoolers utilizes a MEMS-enabled gas compressor coupled to a micro cold stage. Two cold stages have been developed: one which uses a fiber-enabled heat exchanger assembled to a micro-machined throttling valve, and another which uses a MEMS-based heat exchanger. A microcompressor has been developed which uses MEMS-based check valves coupled to a membrane, which is actuated with a mechanically amplified piezoelectric amplifier. The compressor measures a volume 15 mL, can generate a pressure ratio of 6:1 and a maximum flow-rate of 60 standard mL/min. The complete cryocooler has reached low temperatures of 177 K, although temperature instability has been an issue, due to 2-phase flow through the micro-channels. This paper will cover the development and testing of the micro cryogenic cooler, as well as an analysis of the micro channel flow. A proper understanding of the micro-channel flow allows us to design refrigerant mixtures to improve the cooling power, and modify the cooler to eliminate temperature instabilities.Copyright © 2013 by ASME

1 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a comprehensive review of the recent developments and applications of ultra-thin micro heat pipe (UTHP) for thermal management of electronics is presented, and the challenges affecting the development and application of UTHPs are outlined, and recommendations for future research are presented.

245 citations

Journal ArticleDOI
TL;DR: A comprehensive review on recent developments and advances in different types of MEMS-based micro heat pipes and emerging polymer flexible heat pipes is presented in this paper, starting from a brief introduction of basic concept, structure characteristics, and advantages over conventional heat pipes.

90 citations

Journal ArticleDOI
TL;DR: In this article, a novel vapour-liquid channel-separated ultra-thin (0.4mm-thick) vapour chamber fabricated via etching and diffusion bonding was designed for cooling electronic devices.

80 citations

Journal ArticleDOI
TL;DR: Li et al. as mentioned in this paper presented an ultra-thin flat heat pipe (UTFHP) with a total thickness of 0.95mm and an inner height of 0.55mm, which provided strong capillary force as well as low flow resistance for the working fluid.

65 citations

Journal ArticleDOI
TL;DR: In this paper, a biporous condenser-side wick design is proposed that facilitates a thicker vapor core, and thereby reduces the condenser surface peak-to-mean temperature difference by 37% relative to a monolithic wick structure.

63 citations