为了确定所需设备的尺寸，HVAC设计工程师必须能够确定地估计从各种热源添加到环境中的能量，以及通过房间内的各种散热器损失的能量。热量可以从几个来源增加，比如教室或办公室里有很多人，通过窗户的太阳辐射，以及白炽灯房间照明。水槽可以由冬天的外门和窗户组成，也可以由全年基本保持恒温的地下室地板或墙壁组成。通过仔细估计热量的获取或损失，HVAC设备不会因容量不足而尺寸过小，也不会因容量过大而导致成本高昂的未利用过剩容量。 建筑和工业厂房将电力用于许多用途，如照明、驱动机动设备、HVAC以及整个结构的能量传输和分配。所有这些电气设备都构成了总热负荷。估算废热总量是确定建筑所需加热和制冷设备规模的必要部分。直到最近，设计工程师估算电气设备废热的主要信息来源是鲁宾（1979）的论文。在这一广泛使用的文件中，变压器、配电设备、电机、开关设备和电力电缆（仅举几例）的废热值在表中列出了室内设备常见的一系列设备尺寸。 鲁宾提交的数据来自希科克（1978）提交的论文和其他未指明的制造商。希科克在论文发表时曾为通用电气工作，他说，“数据是关于通用电气产品的。”无论是希科克的论文还是鲁宾的论文，都没有讨论测量过程或测量不确定度。鲁宾公布数据的动机是帮助暖通空调设计工程师。希科克在论文中的动机是帮助工厂工程师确定可以提高效率的工厂位置。希科克的动机很容易理解，因为两次石油禁运带来的能源价格冲击使提高现有工厂、建筑和工厂的效率成为降低生产成本的首选。 McDonald和Hickok（1985年）后来合著了Hickok 1978年论文的更新，其中包含了许多相同的数据。这些文件提供的信息是有日期的。自20世纪70年代石油禁运以来，许多电气设备制造商都在努力提高产品的效率。与此同时，电力电子和计算机控制的进步使1970年的设备中反映的许多技术过时。自鲁宾发表其著作以来发生的另一个变化是，适用于各种电力设备的制造标准已多次重新发布和更新。这些标准可以提供测量设备中功率损耗的细节，而这些设备原本可能不存在。 此外，标准可能会规定进行测量的最大不确定度水平，声称遵守标准的制造商报告的任何数据都可能被视为可靠的。因此，有必要更新鲁宾提供的30年前的信息。White和Pahwa（2003a）报告了为提供新的、最新的设备热损失数据以及与部件负荷对应的损失信息而开展的工作。该项目的一个结果是发布了一份用于估算环境热增益的拟议设计指南。White、Pahwa和Cruz（2004a）报告了工作范围，White、Pahwa和Cruz（2004b）报告了设计指南的概要。White等人的工作取得了很大进展。 RP-1104是开发准确估算室内配电设备废热方法的开端。这项工作的目的是继续RP-1104中启动的工作。下一节概述了工作范围。在几种情况下，RP-1395中执行的工作与原始范围不同。以下章节也将讨论这些例外情况。在导言部分之后，将介绍调查结果。

In order to size the required equipment, the HVAC design engineer must be able to estimate with certainty the amount of energy added to the environment from various heat sources and lost through various heat sinks located in a room. Heat could be added from several sources such as the presence of many people in a classroom or office, solar radiation through windows, and incandescent room lighting. A sink could consist of outside doors and windows in winter or a basement floor or wall that remains at an essentially constant temperature throughout the year. By closely estimating the heat gain or loss, the HVAC equipment will not be undersized with insufficient capacity or oversized with costly unutilized excess capability.Building and industrial plants make use of electrical power for many uses such as lighting, driving motorized devices, HVAC, and energy transmission and distribution throughout the structure. All of this electrical equipment contributes to the total heat load. Estimating the total amount of rejected heat is a necessary part of sizing the heating and refrigeration equipment required for the building.Until recently, the primary source of information available to the design engineer for estimating the electrical equipment rejected heat is the paper by Rubin (1979). In this well used document, the rejected heat values for transformers, power distribution equipment, motors, switchgear, and power cables, to name a few, were presented in tables for a range of equipment sizes common to indoor equipment. The data presented by Rubin was obtained from the paper presented by Hickok (1978) and from other, unspecified manufacturers. Hickok, who worked for GE at the publication time of his paper, states, "The data are on General Electric products." At no point in either Hickok's paper or in Rubin's paper is there a discussion of measurement procedure or measurement uncertainty. Rubin's motivation for publishing the data was to aid the HVAC design engineer. Hickok's motivation in his paper was to aid the factory engineer in identifying plant locations where efficiency could be improved. Hickok's motivation is easy to appreciate since the energy price shocks provided by two oil embargoes made increasing efficiency of existing plants, buildings, and factories the first choice in reducing the costs of production. McDonald and Hickok (1985) later co-authored an update of Hickok's 1978 paper with much of the same data.The information provided by these papers is dated. Since the oil embargoes of the 1970s, many electrical equipment manufacturers have taken pains to increase the efficiency of their products.At the same time, advances in power electronics and computer control have made much of the technology reflected in the 1970 equipment obsolete. Another change that has occurred since Rubin published his work is that the manufacturing standards that apply to the various items of power equipment have been re-issued and updated several times. These standards could provide details for measuring the power loss in the equipment where, perhaps, originally none existed.Also, the standards might specify a maximum level of uncertainty for performing the measurements and any data reported by a manufacturer claiming to follow the standard could be deemed reliable. Thus, there is a need to update the 30 years old information presented by Rubin.White and Pahwa (2003a) reported on work undertaken to provide new, up-to-date equipment heat loss data as well as information on losses corresponding to part loads. A result of this project was the issuance of a proposed design guide for estimating the environmental heat gain. The scope of the work was reported in White, Pahwa, and Cruz (2004a) while a synopsis of the design guide was reported in White, Pahwa, and Cruz (2004b). While good strides were completed in the work of White et al., RP-1104 was a beginning in the development of accurate ways of estimating the rejected heat of indoor electrical distribution equipment.The purpose of this work is to continue the effort initiated in RP-1104. The scope of the work is outlined in the following section. In several situations, the worked performed in RP-1395 differed from the original scope. These exceptions are also discussed in the following section. Following the introductory section, the results of the investigation are presented.