真的需要回头客吗？如何正确控制回程风扇？这是关于可变风量（VAV）系统的两个最常见问题。这些问题的答案因个人偏好和经验而异。一些设计师几乎总是使用回风机，而另一些设计师几乎从不使用回风机。有些人甚至难以区分返程球迷和救援球迷。本文不会试图对上述问题提供具体答案，但会指出实际工作中出现的问题以及为纠正这些问题而采取的步骤。这些项目的控制方法不一样，至少在一种情况下，正确的解决方案是消除回风机。 本文希望指出解决方案，帮助读者解决类似问题，并指出新项目设计中需要避免的潜在问题。单位:双引文:研讨会，ASHRAE交易，1988年，第94卷，pt。德克萨斯州达拉斯1号

Are return fans really needed? How do you properly control return fans? These are two of the most frequently asked questions regarding variable air volume (VAV) systems. The answer you get to these questions varies with a person’s personal preference and experience. Some designers almost always use a return fan, others almost never. Some people even have difficulty differentiating between return fans and relief fans. This paper will not attempt to provide specific answers to the above questions, but it will point out problems that have occurred on actual jobs and the steps that were taken to correct the problems. The control methods on these projects were not the same, and, in at least one case, the proper solution would be to eliminate the return fan. This paper will hopefully point out solutions that may help readers with projects that bare similar problems, and point out potential problem areas to be avoided in design of new projects.Units: Dual