大型住宅无水箱电阻热水器的高功率要求对电力系统配电线路、变压器、断路器和其他设备的影响是电力公司和建筑商都关心的问题。本研究旨在分析大型（28 kW）住宅无水箱电热水器与住宅应用中4.5kW储水式（水箱式）热水器的电力需求的可能性和最坏情况，并与给定配电线路上的住户数量进行比较。这项工作开发了方法，以估计无水箱和水箱式热水器最可能（统计上最可能）和3西格玛（统计上不可能，但理论上可能）最坏情况下的多样化电力需求，作为家庭数量的函数。正如预期的那样，单户家庭的热水用电需求峰值与热水器的最大额定功率相对应。 然而，随着更多家庭的增加，热水使用的时间多样性迅速增加，导致随着配电系统中家庭数量的增加，大型无水箱电热水器的多样化电力需求从最大值迅速下降。即使只有少数（2到10）户家庭使用特定的配电系统，可能的无水箱热水器多样化电力需求也仅略高于水箱式机组，并且随着更多家庭的增加，其继续下降。重要的是，这项工作使用三种完全不同的方法计算各种电力需求估计，结果表明，有多种分析技术都能得出相同的结论——即28千瓦无水箱电热水器的多样化电力需求迅速下降到接近4.5千瓦储能电热水器的水平，即使只考虑少数家庭。 引文:ASHRAE Transactions，第123卷，pt。2

The impact of the high power requirements of large residential tankless electric resistance water heaters on electric system distribution wiring, transformers, breakers, and other equipment is of concern for both electric utilities and builders. This study was undertaken to analyzehowprobable and worstcase diversified electrical demand of large (28 kW) residential tankless electric water heaters compares to that of 4.5kWstorage (tank-type) water heaters in residential applications as a function of the number of households on a given electrical distribution circuit.This work developed methods to estimate both most likely (most statistically probable) and 3-sigma (statistically improbable but theoretically possible) worst-case diversified electrical demand for both tankless and tank-type water heaters as a function of the number of households. As expected, single households experience peak water heating electrical demands that correspond to the maximum power rating of the water heaters. However, time diversity of hot-water use increases rapidly as more households are added, resulting in diversified electrical demand of large tankless electric water heaters dropping rapidly from maximum values as the number of households on an electrical distribution system increases. Probable tankless water heater diversified electrical demand drops to levels only slightly higher than for tank-type units when even only a few (2 to 10) households are on a given distribution system, and it continues to drop even further as more households are added.Importantly, this work computes diversified electrical demand estimates using three totally different methods, showing that there are multiple analysis techniques that all lead to the same conclusions--namely that diversified electrical demand of 28 kW tankless electric water heaters rapidly drops to levels near to that of 4.5 kW storage electric water heaters when even only small numbers of households are considered.