与二氧化碳相比，臭氧和氢氟碳化合物（HFCs）的潜在环境损耗是可以忽略不计的。到目前为止，还没有研究典型AC/HP设备中二氧化碳的超临界传热和压降数据。这些数据对于设计用于二氧化碳的热泵和空调设备至关重要。本研究的目标是:为热泵和空气的典型热流量和质量流量范围内的二氧化碳管内气体冷却生成基本的局部超临界传热和流体流动数据- 调节热交换器，量化强化表面管道的影响，以及冷冻油对超临界传热系数和压降的影响。1997年7月-1997年5月由加州大学流体传输研究所主办

Carbon dioxide (R-744) is a naturally occurring substance which is environmentally benign with no ozone depletion potential and negligible global warming potential if compared to CFCs and HFCs. The supercritical heat transfer and pressure drop data for carbon dioxide in typical AC/HP equipment have not been investigated so far. This data is essential in order to design heat pump and air-conditioning equipment to be used with carbon dioxide. The objectives of this research are: to generate basic local supercritical heat transfer and fluid flow data for in-tube gas cooling of carbon dioxide for heat and mass flux ranges typical of heat pump and air-conditioning heat exchangers and, to quantify the effects of enhanced surface tubing and the effect of refrigeration oils on supercritical heat transfer coefficients, and pressure drop.Principal Investigator: Eckhard Groll, Purdue UniversityConducted: May 1997- July 1999Sponsored by: TC 1.3, Heat Transfer and Fluid Flow