Heat pump water heaters are highly efficient hot water supply systems that effectively utilize the heat of outdoor air via heat pump technology. Many studies have been conducted to optimize the design and operation of heat pump water heaters from the perspective of climate change mitigation. Air-source heat pump water heaters, which absorb heat from the outdoor air and emit cold exhaust, can also be expected to alleviate the urban heat island effect; however, this has not been studied extensively. To estimate the impact of cold exhaust on building-scale climate, we conducted a multipoint measurement of the outdoor thermal environment around a low-rise apartment building equipped with air-source heat pump water heaters, in both summer and winter. Observations showed a substantial cooling effect that decreased air temperatures by 1 °C within the site boundary on summer nights when multiple heat pump water heaters operated concurrently. The analysis revealed that the sensitivity of the ambient temperatures to cold exhaust depends strongly on local atmospheric conditions. The most influential factor was the wind direction: the sensitivity increased significantly when the exhaust outlet location was at the lee side of the building. Naturally, the wind speed also affected the sensitivity, which tended to be higher when the wind speed was lower. The convective stability near the ground surface, however, showed no significant influence over the sensitivity.

热泵热水器是一种高效的热水供应系统，通过热泵技术有效利用室外空气的热量。许多研究从减缓气候变化的角度来优化热泵热水器的设计和运行。空气源热泵热水器从室外空气中吸收热量并排出冷气，也有望缓解城市热岛效应；然而，这尚未得到广泛研究。为了估计冷排风对建筑尺度气候的影响，我们在夏季和冬季对配备空气源热泵热水器的低层公寓楼周围的室外热环境进行了多点测量。观察结果表明，当多个热泵热水器同时运行时，夏夜现场边界内的空气温度降低了 1°C，产生了显着的冷却效果。分析表明，环境温度对冷排气的敏感性在很大程度上取决于当地的大气条件。影响最大的因素是风向：当排气口位置在建筑物的背风侧时，灵敏度显着增加。当然，风速也会影响灵敏度，风速越低灵敏度越高。然而，地表附近的对流稳定性对灵敏度没有显着影响。分析表明，环境温度对冷排气的敏感性在很大程度上取决于当地的大气条件。影响最大的因素是风向：当排气口位置在建筑物的背风侧时，灵敏度显着增加。当然，风速也会影响灵敏度，风速越低灵敏度越高。然而，地表附近的对流稳定性对灵敏度没有显着影响。分析表明，环境温度对冷排气的敏感性在很大程度上取决于当地的大气条件。影响最大的因素是风向：当排气口位置在建筑物的背风侧时，灵敏度显着增加。当然，风速也会影响灵敏度，风速越低灵敏度越高。然而，地表附近的对流稳定性对灵敏度没有显着影响。当风速较低时，它往往会更高。然而，地表附近的对流稳定性对灵敏度没有显着影响。当风速较低时，它往往会更高。然而，地表附近的对流稳定性对灵敏度没有显着影响。