Thermal Storage without Heat Exchanger

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

CentralMinn

New Member
Jan 10, 2014
2
Minnesota
I've been designing my boiler system for my new home but am getting stuck on the thermal storage. My question is this; can I use a tank(s) without a heat exchanger by basically running these tanks in-line with the rest of the system allowing the boiler to heat the water directly instead of passively through copper coils? I don't see a problem with this and it seems to be much simpler design but I've seen most people using heat exchangers in tanks. I have access to all the 330 gallon IBC totes I want so I was planning on spray foaming 2 or 3 of them and running them in series (in the bottom, out the top) and in-line with my system. The totes are HDPE and inside steel cages and rated for 230 degree F constant temps. I guess I am hoping to hear that this will work the same as running coils through a tank but the only difference is having a much higher volume in the system. I think this would work great but I want to consult the experts here.
 
Typically boiler systems are pressurized - and the totes couldn't be. Search this forum, there is a huge amount of information here.
 
If I was planning a new build, I'd be hard pressed to justify an OWB for it. Would be down there on my list at least.


I agree. I think one of the selling points of an OWB is that it more easily added on to an existing house. If I was building new I would plan to have my heating system must more integrated into the house.

K
 
If I was planning a new build, I'd be hard pressed to justify an OWB for it. Would be down there on my list at least.

I 100% agree, the more I think about it, it really does not make sense to put a heating appliance outside of the building envelope.

Keeping 200 gallons of boiler water at 185F in the outside air at -25F in an OWB.
That's a 210F temperature difference.

There is no way you gone get a lot of heat inside the house.

The heat wants to go where it is the coldest, ... well that's what I remember from my physics teacher, correct me if I'm wrong.

A little fiberglass insulation or so around the OWB is not gone make much of a difference.
 
Whatever storage you put in, you'll want to avoid oxygenating the water, since this will corrode your boiler pipes. If you have A closed boiler loop with heat exchangers in the tank, then the tank can be open to the atmosphere. If you want to circulate the tank water directly through the boiler, then you'll have to close off the tank to the atmosphere and add an expansion tank to accommodate roughly 4% expansion of the water from 70deg to 185deg. Thus the system will become somewhat pressurized.
 
Status
Not open for further replies.