Plate Heat Exchanger For Hydro Coil?

Rizz861

I was wondering what your thoughts are on adding a flat plate heat exchanger to a hydro coil in an attic to prevent freezing? The heat exchanger would be inside the condition space and piped into the attic for the hydro coil.

I know the whole system could be filled with glycol, but I would be interested in learning about how the setup I just mentioned would work as I don't have much experience dealing with flat plate heat exchangers.

My thought would be the loop for that hydro coil zone gets tied into one side of the heat exchanger, and another loop with glycol and a circulator pump gets tied to the hydro coil. Is that the gist of it?

How do you go about sizing the flat plate heat exchanger? How would you go about sizing the circulator pump for the glycol loop? And what sort of control wiring/relay would facilitate the glycol pump? Would that be a Taco SR501 relay that pulls line voltage from the air handler and the R & W land on the air handler to activate it?

Also, is there any sort of special piping necessary to accomplish this other than a means to isolate and purge?

I apologize for the newbie question, but I know you guys on here are awesome and I'd really appreciate your thoughts.

Thanks!

DCContrarian

I'm trying to understand what you're trying to do. You want to heat the attic? Is it inside the building envelope (unvented) or outside (vented)? Do you have insulation?

Flat plate heat exchangers are tricky, you have to have a circulator on both sides and they have to be matched, the amount of heat transferred is going to be limited by whichever side has the lowest rate. Taco makes ones that are an integrated unit with both circulators and control logic but they're expensive, around $1500.

hot_rod

You want to protect a hydro coil in the attic to prevent freezing, perhaps during a power outage?

Plate HX are commonly used to separate flows. For snowmelt, dhw, at risk piping etc

Plenty of free software programs to do the sizing

This journal takes you through the steps to manually or electronically size one, plate size flow calcs and pump selection

https://idronics.caleffi.com/magazine/29-heat-exchangers-hydronic-and-plumbing-systems

Big Ed_4

Why not glycol the whole system , just pump in the correct type for your system …