The Smart Growth Blog

What's in a heat rejection fluid?

Written by Geoff Brown | Mar 2, 2023

In this episode of FAQ with AGIQ, we're touching on how to get heat out of your building, and what's in a heat reduction fluid.


Episode Transcription:

In today's FAQ with AGIQ, we're going to talk about how to get heat out of your building, and what's in a heat reduction fluid. So traditionally with air conditioners, the primary way of getting heat out of your building has been through a condenser or a condensing unit where refrigerant travels outside. It phase changes in that condenser and rejects its heat.

And that's a very efficient way to do things. It's a single transition process, so it's a very efficient way to do that. But there are some pretty significant considerations that make it challenging in this market. The simplest of which is air conditioners are generally not designed to air condition in the winter. It's not a condition that your average home air conditioner or light commercial air conditioner ever sees. An office building doesn't need air conditioning in the winter, generally speaking.

So what happens is you end up with a refrigeration system that's really just not tuned to having a very cold condenser, and you can end up with low ambient concerns. You guys have all heard about low ambient concerns and what that means to you. One of the other ways to reject heat is to use an intermediate fluid of some kind - water with a cooling tower, a glycol solution with a dry cooler or fluid cooler.


AGronomic IQ Dry Cooler Technology

There's a bunch of different options out there, but basically what the what that intermediate fluid does is it allows your refrigeration system to be isolated from the outdoor condition. So when it's super hot outside, you've got the ability to potentially do a phase change with something like a fluid cooler or a close up cooling tower. And when it's super cold outside, you don't need to expose your refrigeration circuit to that cooling fluid.

That cooling fluid is a secondary loop, and that allows for efficient operation at virtually any outdoor condition. It also has the advantage of vastly reducing your future refrigerant liability. You can imagine that if you're running refrigerant lines hundreds of feet out of your building, you've got to have refrigerant in those lines and it's a pure volumetric consideration. So, the  larger your refrigeration system is, the more refrigerant you need - and refrigerant is expensive and refrigerants go out of style.

You know, we're in the midst of a global warming potential reduction in refrigerant that's going to force a refrigerant trenches transition over the next three years and then over the next seven. Both of those are going to be very expensive in the future for maintenance. Even today, something like R22 is going for north of $100 a pound.

So, if you've got a refrigeration system that can reduce your overall for your overall refrigerant charge by means of a secondary fluid, you can avoid a huge potential future liability when you're maintaining that system down the road. A lot of considerations here, but in general terms, I'm a big proponent of a secondary heat exchange fluid. It makes a lot of sense, It's very flexible. It increases your reliability in terms of low ambient or high ambient, and it reduces your future liability from a maintenance perspective.

I think it's a no brainer.

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