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Member Post posted an update
@Member Post
“I’m going to install two YLAA155 air cooled chillers for process cooling using 45% DowTherm SR1. Standard evaporator flow is 2.2gpm/Ton. Is there a need for a correction factor with glycol?Has anyone used heat recovery option with a YLAA? The manual says it can recover up to 85% of heat and up to 145°.
I was wondering about using it as a heating/preheat for a makeup air unit.
KSEA120 chiller Pic for attention. Not a YLAA but at same customer.”
Member Post, Member Post and Member Post3 Comments-
45%….dang they are running that temp quite low. That’s a heavy mix and definitely yes there is a correction factor with glycol. Hopefully your pumps are sized correctly for use with glycol
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@jasonjohnsonhvac agreed
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You can backup the target flow with correction factors for sure.
If you select a standard unit Rated to ANSI standards with water, there will be a glycol correction factor for the evaporator heat exchanger. You can get close with the published data from Dowtherm. It will account for the pressure drop increase, and also the reduction in heat transfer at various temperature ranges. You will also need to verify with the evaporator manufacturer. (See screenshot i included).
You should have this accounted for in the selection of the equipment. Most suppliers software have the ability to enter your desired specification into their system and size it accordingly.
All of that said, Bill Wren is correct in saying to get the stamp of approval to eliminate any possibility of damaging a customer relationship.
BTUs out = BTU’s in x 1.25 (approximately). The biggest change on a machine with a high concentration of glycol running in cooling mode is the evaporator / pump selection. You don’t want spend a bunch of extra money to get a machine thats oversized when it really just needed a different evaporator / pump selection. There are also other bells and whistles the OEM might require depending on what your design cooling temps are, and what your doing in cooling VS heating mode.
Even if you do all of the math, and work with the rep 1 on 1 to get you the correct selection and data sheet. I would pay an engineer an hour before you order it to look it over and put their stamp on it.
Its cheap insurance. Protect your reputation.
Dow publishes their own literature as well you can look up. we have a guide we made on correction factors that we can send you if you want. Let me know
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