How to Model Chilled Beams in eQUEST

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How to Model Chilled Beams

In this tutorial, we’re going to cover how to set up an active chilled beam system in eQUEST. eQUEST does not have a chilled beam system as a pre-set system type, so we’re just going to set up some type of system that we get a chiller in the model, and we’re going to end up using an induction unit. We’re just going to select anything here, because we need to move to detailed mode. Finish — we’ll go into detailed mode. Pull up this render. The whole point of selecting that system type was just to get a chilled water loop.

We’re going to go to the water side HVAC tab. What we have to do is we have to create a circulation loop. Just right-click at the project — typically we could do this elsewhere. Create circulation loop. Forgot to move into detailed data edit. We could also right-click on the Chilled Water Loop and create another circulation loop. We’ll crate it from scratch. 

It’s going to be a chilled water circulation loop type. We get this screen — we probably should have given it a name. We’ll call it Chilled Beam Chilled Water Loop. The loop type is chilled water. The loop subtype is actually going to be secondary. We have to say the primary loop is just going to be the chilled water loop. Some source of chilled water. One thing that may happen, you may need to select this twice — get the page to refresh, and we get this additional field here. So, we have the sizing option as secondary, the design temperature is typically something like 54, of course that can vary. The design Delta T is 8 degrees. We’d also want to put in the pipe head, or some sort of pipe sizing. We’ll put in 30 feet of head for the pipe. 

So the primary loop is the chilled water loop, and there’s this percent transient to primary. If we assume that the loop Delta T is 12 degrees and the second loop delta T is 8, we have 67 percent, or two-thirds. 67 percent, for the transient to primary. That’s all there is to setting up this secondary loop. 

From here we have to set up the Air-Side system. So if you go to the Air-Side HVAC module, I had selected some VAV systems, but we can change that. First thing we do here is change the type to Induction Unit. We’ll give this a name — Induction Unit. 

In theory, you could set up different systems in the wizard so that you don’t have to do it this way, but we have to enter the fields anyway. So for the fans, under the flow parameters, there’s an induction ratio. The induction ration equals the ratio of the induction air, the room air, or the secondary air, to the ratio of the primary air, which could be ventilation. We’re going to assume that’s something at a 4:1. We’ll go ahead and select the outdoor air tab. We’re going to set a Dual Enthalpy economizer. Then we just have to set the cooling decks, so we go to the cooling tab. 

The Cooling Zone Entering Minimum Supply Temperature — this is going to be 60 degrees. For the Cooling Cold Deck Minimum Leaving Temperature, we also set that as 60 degrees. Now here’s where this gets somewhat fun and we can have some variance depending on your design, but so far so good. We have the cooling control, and that’s going to be scheduled. We’re just going to select the placeholder, here. That’s going to be scheduled. 

Basically, the trick here is that we have to set up three seasons. We have our winter temperature, our spring month temperature, and our summer temperatures, and that is going to depend on your climate, of course. I’m going to assume some sort of Northeast climate. Naturally, you can make this more complex than what I’m going to do. 

Let’s go to Schedules > Daily Schedules > Create Day Schedule. I’m going to call this “CB Clg SAT Sch Swing” — this is going to be a temperature schedule.