大多数美国家庭使用天然气供暖，尤其是在中西部和东北部。对于这些家庭来说，80%以上是由热空气炉加热的，热空气炉的效率从80%到98%不等。最近，更高效的“冷凝”模式(≥ 90%已经饱和了市场，尤其是在北部各州，不断变化的联邦标准将进一步推动“冷凝效率”加热设备的采用。目前，除“冷凝”模式外，没有更高效的燃气机组。展望未来，一种新兴的燃气热泵将继续向高效燃气供暖的方向发展。作者回顾了用于空间供暖的住宅规模燃气热泵（GHP）的最新开发和演示结果，包括实验室和现场评估的结果。现场评估包括在提供空间供暖的商业建筑上安装的装置，以及提供空间和水供暖的住宅。 GHP基于单效吸收循环，并使用有利于大规模生产的组件进行设计。GHP具有巨大的节能潜力，预计在47°F时的AFUE为140%，可以代表家庭供暖的转变，为最终用户和效率倡导者带来挑战和机遇。作为热泵，GHP的输出容量和效率受运行条件（例如室外温度）的影响，虽然由于吸收循环的性质，这些影响小于典型蒸汽压缩热泵，但它们与传统的气体加热设备有很大不同。此外，还有基础设施方面的考虑，例如GHP通常需要户外安装，从而将燃烧过程转移到户外，这从通风和燃烧安全的角度来看是有益的，但也需要与冻结相关的安装成本- 容许间接循环回路。除了回顾与传统气体加热设备相比的这些挑战和机遇外，作者还概述了GHP的发展，包括性能目标、GHP设计和受控实验室条件下的原型性能。引文:2017年冬季会议，内华达州拉斯维加斯，会议论文

The majority of U.S. homes are heated by natural gas, particularly in the Midwest and Northeast. For these homes, over 80% are heated by warm-air furnaces which range in efficiency from 80% to 98% AFUE. Recently, higher efficiency "condensing" models (≥ 90%) have saturated the market, particularly in Northern states, and shifting federal standards will further drive adoption of "condensing efficiency" heating equipment. Currently, there are no higher efficiency gas units beyond the "condensing" models. Looking ahead, an emerging class of gas-fired heat pumps could continue this drive towards high-efficiency gas heating. The authors review findings from a recent development and demonstration of a residential-scale gas heat pump (GHP) for space heating, including results from laboratory and field evaluations. The field evaluations include an installation on a commercial building where space heating is provided and a residence where space and water heating is provided. The GHP is based on the single-effect absorption cycle and is designed using components that favor mass-production. With a large potential for energy savings, a projected AFUE of 140% at 47°F, the GHP can represent a shift in home heating that present both challenges and opportunities for the end users and efficiency advocates alike. As a heat pump, the GHP output capacity and efficiency are affected by operating conditions (e.g. outdoor temperature) and while these effects are smaller than on typical vapor compression heat pumps due to the nature of the absorption cycle, they differ greatly from conventional gas heating equipment. Also there are infrastructure considerations, such as that GHPs typically require outdoor installation which shifts the combustion process outdoors, a benefit from a venting and combustion safety perspective, but also require the installation cost associated with a freeze-tolerant indirect hydronic loop. In addition to reviewing these challenges and opportunities in comparison to conventional gas heating equipment, the authors provide an overview of the GHP development, including performance goals, GHP design, and prototype performance under controlled laboratory conditions.