准确确定冷负荷对于正确确定空调设备的尺寸非常重要。建筑材料隔热性能的改善和建筑围护结构系统的最新进展降低了来自外部来源的建筑冷负荷。然而，由于增加了各种办公室和实验室设备（如微型计算机、显示器、打印机、复印机、扫描仪、投影仪、微波炉、培养箱等），内部冷负荷源的数量有所增加。在本文中，评估了典型的办公室和实验室设备，如台式计算机（带有奔腾和486DX2-33处理器）、显示器、复印机、激光打印机和生物培养箱，以确定这些设备的总热增益以及辐射热增益和对流热增益之间的分配。 此外，使用两个具有明确辐射热损失特性的标准对象，一个加热平板和一个加热球体来验证测量和数据简化程序的准确性。即使在连续运行的情况下，经过测试的办公设备的总热增益也明显低于铭牌额定值。实际功耗为铭牌额定值的14%至36%。因此，在估算空调设备尺寸的总热增益时，使用设备铭牌额定值时必须小心。办公设备的辐射热负荷和对流热负荷之间的分配也是影响冷负荷计算的一个重要因素。热增益的对流部分是瞬时负荷，因为它通过自然或强制对流无延迟地添加到室内空气中，而热增益的辐射部分被室内表面吸收并随时间消散。 总热增益的辐射部分从激光打印机的最小11%到培养箱的最大57%不等。加热表面的辐射部分热增益较高，约为60%。研究了在没有复杂环境室的情况下，使用扫描辐射计方法进行现场测量的可能性。检查的因素包括室内空气温度、空气运动、壁温不均匀和室内空气温度波动的影响。不均匀壁温似乎是最重要的房间相关因素检查。温度高于房间其余部分约10°F（6°C）的一面墙使被测项目的辐射热增益降低约27%。 与正常的室内空气运动一样，室内空气温度的影响不大。波动的室温几乎没有影响。这些结论是基于本项目测试中使用的典型办公空间条件得出的。然而，肯定还有其他可能的房间条件会对辐射热损失产生更大的影响。因此，本文给出的结论不应适用于极端条件。单位:双引文:研讨会，ASHRAE交易，1998年，第104卷，pt。1A，旧金山

An accurate determination of the cooling load is important in the proper sizing of air-conditioning equipment. Improvements on the thermal insulation characteristics of building materials and recent advances in building envelope systems have reduced the building cooling load from external sources. However, the number of internal cooling load sources have increased due to the addition of various office and laboratory equipment (e.g., microcomputer, monitor, printer, copier, scanner, overhead projector, microwave oven, incubator, etc.).In this article, typical office and laboratory equipment such as desktop computers (with a Pentium and a 486DX2-33 processor), monitors, a copier, a laser printer, and a biological incubator are evaluated to determine the total heat gain and the split between radiant and convective heat gain from these items. In addition, two standard objects with well-defined radiant heat loss characteristics, a heated flat slab, and a heated sphere are used to verify the accuracy of measurement and data reduction procedures.The total heat gain from tested office equipment was significantly less than the name plate ratings even when operated continuously. The actual power consumption ranged from 14% to 36% of the name plate ratings. Thus, care must be taken when using equipment nameplate ratings in estimating total heat gain for air-conditioning equipment sizing.The split between the radiant and convective heat load from the office equipment is also an important factor affecting the cooling load calculations. The convective portion of the heat gain is an instantaneous load since it is added to room air by natural or forced convection without time delay, whereas the radiant portion of the heat gain is absorbed by the room surfaces and dissipated over time. The radiant portion of the total heat gain ranged from a minimum of 11% for the laser printer to a maximum of 57% for the incubator. The radiant portion of heat gain from the heated surfaces was higher at about 60%.The potential for using the scanning radiometer method for field measurements where sophisticated environmental chambers are not available was examined. Factors examined included the effect of room air temperature, air motion, nonuniform wall temperature, and fluctuating room air temperature. Nonuniform wall temperature appeared to be the most important of the room-related factors examined. One wall at a temperature of approximately 10°F (6 °C) above the rest of the room decreased the radiant heat gain of the measured items by approximately 27%. Room air temperature had only a modest impact as did normal room air motion. Fluctuating room air temperature had very little effect. These conclusions are based on the conditions used for the tests in this project that are typical of office space conditions. However, there certainly are other possible room conditions that would impact the radiant heat loss more drastically. Thus, the conclusions presented herein should not be applied to extreme conditions.Units: Dual