Options to adding DHW to a closed loop system.

[Flexia]

I have been thinking about adding a DHW to my garage build. Its not a necessity but would be nice. My idea is to have the heating system be the primary system and add a heat exchanger on to pull heat off my heating system to have warm water. I don't need DHW all the time so thats why I would make it the secondary system. I plan to put a flow switch on the DHW line that would trigger a pump on the heating loop so I would have circulation to the exhanger. Is this a feasible option?

 

[anthony666]

I have been thinking about adding a DHW to my garage build. Its not a necessity but would be nice. My idea is to have the heating system be the primary system and add a heat exchanger on to pull heat off my heating system to have warm water. I don't need DHW all the time so thats why I would make it the secondary system. I plan to put a flow switch on the DHW line that would trigger a pump on the heating loop so I would have circulation to the exhanger. Is this a feasible option?

yes .. very feasible .. do it all the time

flow switch to tt on the boiler .. tube and shell heat exchanger on the hot primary leg and let it short cycle back into the boiler .. the only question is delivery temp .. if you run your dhw at floor temp its not gonna be very hot .. if you run the boiler at dhw the slab will break up .. unless of course you got a fancy boiler that does a separate delivery temp when it gets a dhw call, those bad boys arent cheap

 

[Flexia]

Yeah I understand it won't be hot. But I basically want warm water to wash cars with and can't justify a combi boiler for the limited time I'll use it. I think this would be the perfect option. Now I just need to figure a heat source.

Slapped X on Tapatalk

 

[LS6 Tommy]

Sounds like a decent plan if you're not looking for really hot water. BTW, I don't recommend you use hot (or even above like warm) water to wash a car outside on a truly cold day unless you like your local auto glass installer...


Tommy

 

[Jackfre]

Not sure of your lay-out, house to garage, but perhaps it would be better to simply run a bit of pex from your home water heater to a hose bib on the garage side. I have to say that is one of the things I like about my tankless water heater. When I wash the dog or the car I just set the control to 98* and that is what it delivers.