Question about: Simplest Pressurized Storage System Design

[sgschwend]

I like you design, but I don't see why the zone circulator pump would not circulate the fluid through the boiler too (when the boiler is cold and the storage is hot). I would think the fluid would flow based on the line resistance.

Tlhanks for the help

Steve

 

[Nofossil]

I like you design, but I don't see why the zone circulator pump would not circulate the fluid through the boiler too (when the boiler is cold and the storage is hot). I would think the fluid would flow based on the line resistance.

Tlhanks for the help

Steve

You're right that it could induce 'ghost flow' through the boiler. In the schematic as drawn, the orientation of the tees above and below storage is intended to encourage flow through storage, and the expectation is that the storage plumbing is large diameter such that there is virtually no head loss across storage. There are check valves in the boiler circs that provide some resistance to ghost flow, and a flo-check valve could be installed in the line between the boiler outlets and storage to further ensure that here is no ghost flow.

In some variants of this design, the boiler loop and the zone loop each connect independently to the top and bottom of storage. This guarantees that there will be no ghost flow at the cost of getting a bit of mixing in storage when you might want to just be heating the zones.

There is also a possibility that the oil might end up heating storage a bit if the zone demand is low. I've attached a variant that prevents this problem as well as a second variant that's plumbed with independent storage connections.