Series or Parallel connection for non-pressurized storage

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Space Cadet

New Member
Jan 23, 2008
5
St. Louis
I have a 500 gallon tank I am wanting to use for non-pressurized heat storage on my pressurized system. My question is, should I plumb the heat exchanger in series with my loop or parallel? Supply or return side of the boiler? Thanks!
 
Welcome to the Boiler Room, Space Cadet. What kind of boiler do you have?

There are many different ways to pipe up a storage tank and hx, but I would set it up so that the supply water from your boiler could be switched to flow directly to either the hx on the tank or your heating zones, depending on where the heat is needed the most. You can do that with a three-way zone valve, a manual (ball) valve, or some other control strategy. Basically, when your house needs heat, you should be able to bypass the tank. When the house is satisfied and the boiler is still putting out heat, you want to be able to divert the water flow to the tank.
 
Thanks for the replies. Sorry for the long post, but I thought a little more information probably wouldn't hurt.

My boiler is very similar to this, I think mine may be a 2nd revision..The only noticeable difference is the door; mine is round, the one in the link is square on sides and bottom.

https://www.hearth.com/econtent/index.php/wiki/Furnace_Works_Boiler

It's old. It can be a smoke dragon sometimes. It's installed outside, and will soon (weather permitting) have a small shed around it. It burns pretty clean if it's not idling, but it won't make heat after 4 hours when the load is high. My overall system efficiency is pretty low right now, especially because of the loss to the outside air (boiler is uninsulated). Boiler is 140KBTU, Forced Air HX @ 80KBTU, heats my garage/workshop and an attached 2 room apartment (Separate stove for the house right now). Wood is usually free for me and in good supply.

Problem is, the whole system only holds 15 gallons. Firebox is 5.3 cu/ft. When outside temp drops below 30, I can barely get 4 hours on a load of wood. The fire is still burning, but not making enough heat.

I figure with the storage tank, I will be able to burn nice and clean at full throttle, at the same time getting more than 4 hours of heat between "servicing". This installation is a work in progress. I am sure once the shed is completed, and boiler is insulated, efficiency will go up.
 
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