试验在一个无人居住的研究室中进行，以量化回流管道改造对变速燃气热泵（GHP）加热和冷却性能的影响。最初的回风管道系统由大多数楼层回风室组成，回风室与地下室的未隔热金属板管道相连，回风温度约为70华氏度。安装了一个隔热中央回流管，并在两个冷却季节和一个加热季节测试了四种回流系统配置。（1） 非绝缘低回流配电系统（2）带金属板延伸的配电系统，以提供高回流（3）带低回流的绝缘中央回流管道系统（4）带高回流的绝缘中央回流管道系统。 每小时收集能源消耗、供暖和制冷输出以及空间条件数据。使用多元线性回归法分离回流管道系统选项的影响。回风管系统的变化对GHP的加热性能没有显著影响。在制冷季节，能耗大幅降低。据预测，在芝加哥的一个典型年份，冷却季节的能源节约将高达燃气消耗量的21%和电力消耗量的17%。关键词:热泵、燃气机热泵、性能、住房、美国、管道、供暖、空间供暖、冷却、隔热、变速电机、能耗、冷却季节、燃气消耗、电力消耗。 引文:研讨会，ASHRAE交易1993，第99卷，pt。1.

Tests were conducted in an unoccupied research house to quantify the effects of return ductwork modifications on heating and cooling performance of a variable-speed gas heat pump (GHP). The original return duct system, consisting in most rooms of floor-level returns connected to uninsulated sheet metal ducts in the basement, was returning air at around 70 deg.F in cooling. An insulated central return duct was installed, and four return system configurations were tested during two cooling seasons and one heating season. (1) uninsulated, distribution system with low returns (2) distributed system with sheet metal extensions to provide high returns (3) insulated, central return duct system with low return (4) insulated, central return duct system with high return. Energy consumption, heating and cooling output, and space condition data were collected on an hourly basis. The effects of the return duct system options were isolated using multiple linear regression. The return duct system changes had no significant effects on the heating performance of the GHP. The modifications provided substantial reductions in energy consumption during the cooling season. Cooling season energy savings of up to 21% of the gas consumption and 17% of the electricity consumption were predicted for a typical year in Chicago.KEYWORDS: heat pumps, gas engine heat pumps, performance, housing, USA, ducts, heating, space heating, cooling, thermal insulation, variable speed motors, energy consumption, cooling season, gas consumption, electricity consumption.