为了实现住宅建筑的低能耗运行，先进的热水技术至关重要。本文探讨了一台189升（50加仑）热泵热水器（HPWH）在马里兰州盖瑟斯堡净零能耗测试住宅中的全年性能，该热水器作为一台带有303升（80加仑）储水箱的主动间接太阳能热水器的辅助装置，在2013年7月至2014年6月期间，这些系统受制于一个四口之家的典型用水计划。我们研究了进水温度对HPWH整体系统性能系数（COPsys）的影响以及机组的空间调节影响，因为这些因素可能会因太阳能热水器满足热水需求的程度而发生很大变化。 现场测试表明，已安装的HPWH在当年使用了1104 kWh，其功率因数为1.41，在12个月的测试期间未达到制造商报告的2.33的能量因数（EF）。这种差异很大程度上是因为，与唯一的热水器相比，该装置提供的热水负荷要小得多。考虑到远离电阻储水式热水器的监管趋势，例如美国的现行标准要求储水量大于208 L（55 gal）的电热水器EFs大于1.9，因此对这种独特配置的HPWH进行研究是有价值的。引用:2016年冬季会议，佛罗里达州奥兰多，会议论文

In the effort to achieve low-energy operation of residential buildings, advanced water heating technologies are vitally important. This paper explores the year-long performance of a 189 L (50 gal) heat pump water heater (HPWH) serving as an auxiliary unit to an active, indirect solar thermal water heater with a 303 L (80 gal) storage tank in a net-zero energy test home located in Gaithersburg, MD, USA. Thesystems were subjected to a representative water use schedule for a virtual family of four between July 2013 and June 2014. We investigate the effect of inlet water temperature on the overallsystem Coefficient of Performance (COPsys) of the HPWH and the unit's space conditioning impact, as these factors can vary substantially depending on the extent to which hot water demand is met by the solar thermal water heater. Field testing showed that the installed HPWH used 1104 kWh in the year and had a COPsysof 1.41, not reaching the manufacturer's reported Energy Factor (EF) of 2.33 over the course of the 12-month testing period. The difference was largely due to the fact that the hot water load delivered by the unit was much less than if it were the sole water heater. The study of a HPWH in this unique configuration is valuable considering regulatory trends away from electric resistance storage water heaters, such as current standards in the United States that require EFs greater than 1.9 for electric water heaters with storage volumes greater than 208 L (55 gal).