研制了一种特殊的传热管和由传热管构成的换热器。热交换器是一台额定功率为30000 kcal/h（34900 W）的热水器，用于住宅供暖和热水供应。该管是由直径为30 mm的外管和与外管内表面热接触并具有椭圆形横截面形状的内管构成的同心双管。热水供应用水和住宅供暖用水通过两条路径流动，分别由内管和外管构成。水由煤油的燃烧气体加热。热交换器芯长300毫米，宽300毫米，高100毫米。 得到以下结果:（1）换热器总热效率为85%。（2） 两条路径之一的积水温度较低。引用:ASHRAE交易，第87卷，第一部分，伊利诺伊州芝加哥

A special heat transfer tube and a heat exchanger constructed of tubes have been developed. The heat exchanger is a 30000 kcal/h (34900 W) rating water heater for residential heating and hot water supply. The tube is a concentric double tube constructed from an outer tube, whose diameter is 30 mm, and an inner tube, which is thermally contacted with the inner surface of the outer tube and has an elliptical cross-section shape. Water for hot water supply and for residential heating flows in two paths, respectively constituted from an inner tube and an outer tube. The water is heated by combustion gases of kerosene. The heat exchanger core is 300 mm long, 300 mm wide and 100 mm high. The following results were obtained:(1) Overall heat exchanger thermal efficiency was 85%.(2) Stagnant water temperature in one of the two paths is low.