Anemostat variable volume reset control how to#

zone percentage is say 45%, that you would oversize min. it's good if your maximum zone percentage is say 33% and average percentage is 30%. You should base your calculation on zones that have largest percent of outdoor air (in relation to supply air), and increase minimum outdoor air setting of other zones (proportionally).

air is 30% of the supply air, in others it can be 15% or 45%. in practice it is mostly not possible, as some zones' min.

Anemostat variable volume reset control how to#

The one practical problem mentioned by jazzerman is how to achieve what all vav boxes receive exact amount of minimum outdoor air. You reasoning in initial post seems completely valid for me. RE: Sizing a pre-heat coil with a vav system. You might find that a certain few VAV boxes are causing the AHU sytem vent rate to need to be way higher, and if increase those box mins, you can reduce the AHU vent rate.Īnother thought - if you have many interior zones they might be in cooling year round, rather than heating, and your system desing day heating AHU system cfm might be more than sum of heating mins. Ultimately it involves balancing your VAV box mins versus the AHU min oa rate. An air measuring station is then used in the MIN OA section and the min OA damper modulated to maintain the min OA setting.Ĭheck out ASHRAE 62.1 ventilation rate procedure first. One design that I have done (custom air handler though, not packaged RTU) once I figured out what my minimum outside air is through the 62.1 vent rate procedure was to use a separate minimum OA ventilation duct and modulating damper (separate from the OA economizer damper). You should probably check out ASHRAE 62.1 (if you haven't already) which has a process to calculate the minimum outside air that a VAV air system should use. No, you have valid thoughts Re: ventilation and VAV reheat systems. Wayne RE: Sizing a pre-heat coil with a vav system. Would i assume it's going to see 3,950 of 9 degree air and size the pre-heat for that condition?Īny help? Am i making this harder than it needs to be? 30% of the maximum is 2,850 but i need 3950 to maintain my ventilation.

at 9 degrees at that point?įor example, RTU-2 has a maximum airflow of 9,500 cfm and an o.a. So, would i hvae to size the coil for 100% of my o.a. is more than the minimum 30% airflow, so i would have to have 100% o.a. So, i would not have the maximum airflow across the coil, mixed with the return air from the unit. My question is, if you take a cold morning at design heating conditions, 9 degrees F, i am assuming (and that's not always a good thing) my boxes are going to be at the minimum setting, roughly 30% of my total cfm for cooling. In trying to size the pre-heat coil, my intent is maintain a minimum discharge air from the unit around 55 degrees F and do heating in the spaces with reheat coils in the vav boxes. The system will consist of rooftop units with chilled water coils and pre-heat coils, chillers, boiler, pumps etc, with vav boxes serving the classrooms and offices. Annual Review of Psychology, 66, 825-852.I am working on a 4 story science and mathmatics building for a local college. Advances in mediation analysis: A survey and synthesis of new developments. Journal of personality and social psychology, 51(6), 1173. The moderator–mediator variable distinction in social psychological research: Conceptual, strategic, and statistical considerations. However, if they are, for the 'required' (or better say 'desirable') relationships between IVs and mediator/moderator - see the appropriate methodological literature.ģ. If controls are not part of your mediation/moderation test, then you shouldn't worry much about them. Typically, controls come from literature (or sometimes from common sense. All assumptions of your estimator pertain to your controls in the model (e.g., there should be no multicollinearity between IVs, etc.)Ģ. Let me clarify - two dependent variables - means you have two separate (univariate) models or are you talking about a multivariate model? Now, answering your questions:ġ. Make sure you build on the appropriate literature. Testing for mediated moderation is quite complex, as it requires both strong theoretical grounds and robust empirical support.