Plate heat exchanger

Donniejr

so, I’m adding a zone of heat to a second floor bath. The piping will run through below freezing areas, so I’ll need to antifreeze. I don’t want to antifreeze the entire system. I thought of adding a plate exchanger to that one dedicated zone so I only have to antifreeze the one zone. I’ll need a circulator on the boiler side to heat the plate exchanger and another circulator on the zone side to heat the baseboard. My idea to run both circulators off an SR501 controlled by just the one thermostat. Does anyone have any better suggestions or ideas? Thank you

hot_rod

On the glycol side you want an air purger, pressure gauge, relief valve and expansion tank also

Maybe an Axiom fill tank

jumper

I presume a brazed one? Gasketed likes constant temperatures.

Also you can think about filters for both sides. Not easy to clean brazed plate exchanger.

I'd just get an electric heater for that bathroom.

Alan (California Radiant) Forbes

Heat tape on the exposed piping?

Donniejr

Hot Rod, those things I hadn't considered. However, it makes sense where it will be a closed loop. My brain was thinking that the main zone (only one zone in this entire building!!) had the extrol, air scoop, etc. So, now my supply side of the plate exchanger will have the air scoop, circulator, valves, etc. While the return will have valves, relief valve, drain, gauge, etc. In regards to the circulators and wiring. I was planning to use an SR501. There will be a circulator on the glycol side for the baseboard and a circulator on the boiler side to circulate to the plate exchanger. When wiring the SR, can I just place both circulators on the same terminals so both pumps run at the same time? Otherwise, I'd probably have to run like a Honeywell L4006 to maintain plate exchanger heat. In regards to the Axiom fill tank, I was planning to place a tee between the 911S and the boiler. I hate glycol, but having to use it requires maintenance. So, annually I was planning to test and add, replace, etc. If I go the route of the Axiom fill tank, it would have water with glycol. If not used, would it be a waste? Or were you thinking of using water only? Thank you very much for your help!

Donniejr

Thank you Jumper for responding. Yes, I was considering a brazed plate exchanger like the TB models from Taco or perhaps the Bell & Gossett model. This is my first experience with plate exchangers. In the past I've use sidearms, but nothing like the plate exchangers. You mentioned using filters. Is there one you prefer? I've considered electric baseboard. However, our utility company has crammed rates so far down our throats I don't dare to go that route. Thank you for your help.

Donniejr

Thank you Alan for the response. I was planning to use 3/4" Uponor Wirsbo to run the supply and return. I'm not sure heat tape can be used. The supply to the baseboard and return will be approximately 6' in length total between the two pipes that will be exposed to freezing temperatures. Gotta love old houses. Thanks again

Kaos

This falls into that category where you look at the BOM cost of the hydronic bits VS resistance floor heat and your ROI is measured in decades.

I would install some resistance mats on a nice thermostat that only runs the heat when you'll be using the bathroom and for freeze protection the rest of the time. The operating cost of this will be pretty small and none of the complications of dealing with frozen pipes or glycol.

EBEBRATT-Ed

@Donniejr

You can certainly do the job with hydronic hot water heat. You will need 2 circulators an expansion tank, air eliminators a heat exchanger, glycol and all the piping and wiring and controls.

For me the cost of the above would be prohibitive just to heat a bathroom.

I agree with @jumper above. Some electric baseboards or a wall mounted electric heater with a fan will keep the bathroom toasty

JMHO

DCContrarian

I'd be looking for a route for the pipes that goes through only conditioned space.

Donniejr

Thank you everyone. I really appreciate the help and ideas.

jumper

https://forum.heatinghelp.com/discussion/comment/1813285#Comment_1813285

My advice is to avoid plate heat exchanger. You need pumps that will maintain high velocity to delay fouling. Those pumps also consume electricity. Try to find a small low wattage oil filled electric heater. If you don't have room then install a ceiling height radiant heater. Far simpler than your project.

hot_rod

I had a Myson electric towel bar in a small bathroom. It worked great for a quick warm up.

However if you completely cover it with clothes or towels, you don't get much heat to the space.

If it is a small floor space, a wall mounted towel bar may be a nice option, compared to a space heater. These are designed for safe operation in wet, humid rooms also.

But if you go with a hydronic solution don't fear plate HXers and shop e-bay for good prices. In a clean closed loop system they will not need much if any maintenance.

Plates used on DHW systems do need occasional deliming.

https://www.caleffi.com/sites/default/files/media/external-file/Idronics_29_NA_Heat%20exchangers%20in%20hydronic%20and%20plumbing%20systems.pdf

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Donniejr

Thank you Hot Rod. The info you included was extremely helpful.