#946 airRef (new) vs ahuRef (old)

Eric Loew Thu 16 Sep 2021


My team has been looking at a question regarding airRef (new) vs ahuRef (old).

In this example (https://project-haystack.org/example/alpha/a-0013), which is admittedly old, we see the use of airRef for a discharge-fan-equip to point to the associated ahu.

However, a fan is not an "air-input", so this is not really a valid use of the "airRef" tag (and for those using SkySpark, we get a lint warning).

Previously, we used ahuRef for these cases, and it worked well. However, since "ahuRef" was deprecated to be "airRef", this usage does not really apply (and hence the lint warning in SkySpark).

So, the question becomes, what "Ref" tag does appropriately apply in this case, other than the simple "equipRef", if any.

Brian Frank Thu 16 Sep 2021

I think you can easily make the case that fan and damper should be both an air-input and air-output. This would allow you to use those relationships to order equipment within an air flow (which was discussed previously).

But when I started to get into that earlier this year was when I ran into the problems with how to do it with valves and pumps correctly without exploding all the fluid types. That led to the proposal in 937. Although I'm not positive that 937 fully solves the problem for fluid flows, so we may need to continue to refine that until it handles that use case.

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