屋顶单元（RTU）等成套暖通空调设备通常使用省煤器提供新鲜的室外通风空气，并排出陈旧的建筑空气。新鲜空气进气口和排气罩通常彼此非常靠近，排气罩通常位于进气罩正下方。在这种布置中，在各种工作条件下，一部分排气可重新进入进气。该项目确定了各种风速和风向、RTU设计和周围结构的建筑排气再培训范围。 在两个安装位置的三个屋顶暖通空调机组上收集了实验数据。其中一个装置有一个10吨（35千瓦）的RTU和一个8英尺（2.44米）高的壁障，可以位于排气/进气罩的前面，或装置的一侧，距离为5英尺（1.52米）、10英尺（3.05米）或15英尺（4.57米）。第二个装置有两个相同的15吨（53千瓦）RTU，相距16.8英尺（5.12米），分别测量每个装置以及从一个装置的排气口到另一个装置的进气口的再培训。 六氟化硫（SF6）用于以已知速率增加排气排放，监测设备每小时以10分钟的间隔测量进气口中的SF6再吸入量。在大约一个月的时间内收集了每种不同配置的数据。对单台机组和双台机组进行了计算流体力学建模，与数据吻合较好。单位:双引文:ASHRAE交易，第113卷，第。2.

Packaged HVAC equipment such as rooftop units (RTUs) often use economizers to supply fresh outdoor ventilation air and to exhaust stale building air. The fresh-air intake and the exhaust hoods are typically located very close to one another, often with the exhaust hood directly below the intake hood. In this arrangement, a portion of the exhaust air may be reentrained into the intake air under various operating conditions.This project determined the extent of reentrainment of building exhaust for a variety of wind speeds and directions, RTU designs, and surrounding structures. Experimental data were collected on three packaged rooftop HVAC units at two installation locations. One installation had one 10 ton (35 kW) RTU and an 8 ft (2.44 m) high wall obstruction that could be located either in front of the exhaust/intake hoods or at one side of the unit at distances of 5 ft (1.52 m), 10 ft (3.05 m), or 15 ft (4.57 m). The second installation had two identical 15 ton (53 kW) RTUs located 16.8 ft (5.12 m) apart, and their reentrainments were measured for each unit independently as well as from one unit’s exhaust to the other’s intake. Sulfur hexafluoride (SF6) was used to spike the exhaust air discharges at a known rate, and monitoring equipment measured the amount of SF6reentrainment in the air intakes at ten-minute intervals every hour. Data were collected for each different configuration over a period of approximately one month. Computational fluid dynamics modeling was performed on both the single unit and the twin units, and fairly good agreement with the data was achieved.Units: Dual