| 摘要 |
PROBLEM TO BE SOLVED: To provide an inner helically-grooved heat transfer pipe for an evaporator not increasing pressure loss even when a carbon dioxide refrigerant including refrigerating machine oil is used, and having superior evaporating heat-transferring performance. SOLUTION: In this inner helically-grooved heat transfer pipe 21 for the evaporator, provided with a spiral groove 22 on its inner face, an outer diameter is 3-7 mm, a height h of a fin is 0.14-0.27 mm, further a helix angleθis 2-25 degrees, when carbon dioxide including refrigerating machine oil of 0.1-1.5 mass% is used as the refrigerant, or a cross-sectional area S of the groove part is 0.020-0.053 mm<SP>2</SP>when carbon dioxide including refrigerating machine oil of 1.5-5.0 mass%, non-inclusive of 1.5, is used as the refrigerant. COPYRIGHT: (C)2006,JPO&NCIPI
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