Looking for input on design idea

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mpilihp

Feeling the Heat
Apr 22, 2008
438
Coastal ME
Hello all I am trying to come up with a solution to allow doing three things, see diagram below:

First having separate control for heating my indirect DHW tank via wood boiler or oil boiler once I add storage. Currently (without storage) when no zones call for heat the return path for the wood boiler (WB) is through the indirect DHW tank so when the WB circ is running and not heating the house its charging the indirect DHW tank which has a 3way valve to temper its output. The aqustat on the tank is set to 125deg and controls the oil boiler minimizing it coming on, pretty much to never when we are running the WB.

Second - allow charging the indirect DHW tank to say 170deg. To do this there are two zone valves, A and B and an aqustat (set to 165) on the output side of the indirect dhw tanks heat zone. When the aqustat is below 165d it will Open Zv a and close Zv B causing unused WB heated water to flow through the indirect dhw tank to heat it. Once the aqustat reaches 165d it will close zv A and open Zv B stopping the heating of the indirect DHW tank and send the unused heated water onto the storage tank. This setup will preventing the cooling wb water from cooling the indirect DHW tank. The aqustat will cycle allowing heat water to intermittently keep flowing through the dhw tank all the time insuring it is always hot at the end of the WB firing.

Third - Allow charging the storage tank to the highest value. Again values of the aqustats temps probably will need to be adjusted. So when the indirect DHW tank is satisfied (heat loop temp at output above 165) Zone valve A will close and zone valve B will open. This will cause the flow of WB water to go through the storage tank zone. If the temp of the tank is below 165deg aqustat on storage tank will open Zv C and allow all water to flow through tank, once the tank reaches 165deg that zone valve will close and cause all water to flow through the 3way diverter valve. This valve will only allow water above say 170deg into the storage tank causing the colder water to bypass the tank and return to the WB to be reheated quicker and not bleed heat outof the storage tank.

Does this sound possible/plausable?

Is there a more efficient cheaper way hardware wise to do this?

Can a diverter valve function as I show it? Configured to allow only water above a certain temp through one output?

http://i103.photobucket.com/albums/m132/mjenphil/WoodBoiler/indirect-dhw-and-storage-design.jpg

Thanks
 
Bump

Any thoughts on this guys?

Thanks

~ Phil
 
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