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Copper MicroGroove is a small diameter coil technology for modern air conditioning and refrigeration systems.〔Microgroove: The Microgroove advantage; http://www.microgroove.net/〕 Small diameter coils have better rates of heat transfer than conventional sized condenser and evaporator coils with round copper tubes and aluminium or copper fin that have been the standard in the HVAC industry for many years. Small diameter coils can withstand the higher pressures required by the new generation of environmentally friendlier refrigerants. They have lower material costs because they require less refrigerant, fin, and coil materials. And they enable the design of smaller and lighter high-efficiency air conditioners and refrigerators because the evaporators and condensers coils are smaller and lighter. Two small diameter coil technologies are currently available for air conditioning and refrigeration products: copper MicroGroove, a technology developed by the International Copper Association (ICA);〔Microgroove: The Microgroove advantage; http://www.microgroove.net/〕 and brazed aluminium microchannel.〔Q&A: Microchannel air-cooled condenser; Heatcraft Worldwide Refrigeration; April 2011; http://www.heatcraftrpd.com/landing/2011/air-cooled-condenser/res/pdfs/H-ACCMCX-QA.pdf〕 A third technology, copper micro-channel, developed by Ohio University in conjunction with ICA, is not yet commercially available although the technology to manufacture these tubes has been developed.〔Copper micro-channel tube for HVAC applications; Ohio University Technology Transfer Office; http://www.ohio.edu/research/tto/upload/Kraft-06032-Tech-brief.pdf〕 The performance advantages of copper over aluminium as a heat transfer material include greater heat exchange, better long-term durability and resistance to corrosion, lower cost of maintenance, and copper’s antimicrobial benefits. A unique highlight of MicroGroove technology is that heat transfer is enhanced by grooving the inside surface of the tube. This increases the surface to volume ratio, mixes the refrigerant, and homogenizes refrigerant temperatures across the tube.〔FAQs: Thirty Questions with Answers about Economical, Eco-friendly Copper Tubes for Air Conditioner Applications; http://www.microgroove.net/sites/default/files/overview-ica-questions-and-answers-qa30.pdf〕〔Microgroove Brochure: http://www.microgroove.net/sites/default/files/microgroove-brochure-game-changer.pdf〕〔Microgroove™ Update Newsletter: Volume 1, Issue 2, August 2011: http://www.microgroove.net/sites/default/files/4315_microgroove_newsletter_august_2.pdf〕 Tubes with MicroGroove technology can be made with copper or aluminium. Copper fins are an attractive alternative to aluminium due to the better corrosion resistance of copper and other benefits.〔Microgroove Brochure: http://www.microgroove.net/sites/default/files/microgroove-brochure-game-changer.pdf〕 ==Design== To use smaller tubes instead of conventional sized tubes in air conditioners, heat exchangers must be redesigned. This includes redesigning the fin and tube circuits.〔Principle of Designing Fin-and-Tube Heat Exchanger With Smaller Tubes for Air Conditioner Wei Wu, Guoliang Ding, Yongxin Zheng, Yifeng Gao, Ji Song; International Refrigeration and Air Conditioning Conference at Purdue, July 16–19, 2012 http://www.conftool.com/2012Purdue/index.php?page=browseSessions&abstracts=show&mode=list&search=2223〕 Design optimization requires the use of computational fluid dynamics to analyze airflow around the tubes and fins, as well as computer simulations of refrigerant flow and temperatures inside the tubes. This is important because the overall heat transfer coefficient of a coil is a function of the convection of the refrigerant inside the tube to the tube wall, conduction through the tube wall, and dissipation through the fins.〔Microgroove Brochure: http://www.microgroove.net/sites/default/files/microgroove-brochure-game-changer.pdf〕 Engineering considerations for using Microgroove include: 1) determining the best ratio of transverse tube pitch to longitudinal tube pitch by fin efficiency analysis; 2) optimizing transverse and longitudinal tube pitch by performance analysis and material cost; 3) optimizing fin pattern by comparing performances of fins with different patterns through computational fluid dynamics-based simulations; 4) testing the performance of heat exchangers with smaller diameter tubes; and 5) developing empiric equations for predicting performance of heat exchangers with smaller diameter tubes.〔New Research Underscores Best Practices in Coil Design; Microgroove™ Update Newsletter: Volume 2, Issue 3, June 2012; http://www.microgroove.net/sites/default/files/microgroove_nl_june2012b.pdf〕 Published experiments on MicroGroove coil performance and energy efficiency take into account the effects of fin spacing and fin design, tube diameter, and tube circuitry.〔G.L. Ding et al. (YEAR), 23rd IIR International Congress of Refrigeration, Prague, August 23–26.〕 Tube circuitry is substantially different than for conventional coils. Coils should be optimized with respect to the number of paths between the inlet and outlet manifolds. Typically, smaller diameter tubes require more paths of shorter lengths. Published research on tube circuitry〔Wei-kun Ding et al. (Xi’an and ICA) "Development of Small-diameter Tube Heat Exchanger: Circuit Design and Performance Simulation," presented at the Conference on Thermal and Environmental Issues in Energy Systems, Sorrento, Italy, May 2010 (CTEI-ES 2010)〕 and fin design for heat exchangers made with 4 mm tubes〔Ju-fang Fan et al.; "Development of Small-diameter Tube Heat Exchanger: Fin Design and Performance Research," presented at CTEI-ES 2010〕 are available. Research on a heat exchanger redesign with 5-mm diameter tubes demonstrated a 5% greater heat exchange capacity than that of the same size heat exchanger with 7-mm diameter tubes. Also, the refrigerant charge of the 5-mm diameter tubes was less than the 7-mm diameter tubes.〔Principle of Designing Fin-and-Tube Heat Exchanger With Smaller Tubes for Air Conditioner; Wei Wu, Guoliang Ding, Yongxin Zheng, Yifeng Gao, Ji Song; International Refrigeration and Air Conditioning Conference at Purdue, July 16–19, 2012; http://www.conftool.com/2012Purdue/index.php?page=browseSessions&abstracts=show&mode=list&search=2223〕 In China, Chigo, Gree, and Kelon are producing air conditioners with coils that have 5-mm diameter tubes.〔Cool Technology: Small copper tubes make a big impact on air conditioner efficiency; MachineDesign.com; August 23, 2012; http://machinedesign.com/article/cool-technology-small-copper-tubes-make-a-big-impact-on-air-conditioner-efficiency-0823?page=0%2C3〕 A variety of fin designs have been developed for use with small-diameter copper tubes. The performance of slotted and louvered fin designs have been evaluated and compared as a function of various fin dimensions. Simulations have been used to optimize fin design performance.〔Ju-fang Fan, Wei-kun Ding, Wen-quan Tao, Wenson Zheng, Frank Gao, and Kerry Song; Development of small-diameter tube heat exchanger: Fin design and performance research.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Copper MicroGroove」の詳細全文を読む スポンサード リンク
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