Vie$$man Dual Coil Vitocell 100-B used for DHW & boiler buffer tank?

billyboy

I have a New Dual coil Vitocell 100-B

I'm thinking of using top coil for radiant heating system?
I may need a circulator between DHW port and RT port to increase heat transfer into the top coil?

See:
http://www.viessmann-shop.lv/u…
pg. 6

RT port is the DHW re-circulation return into tank at about the middle of the top coil

top coil = .9M2 = 9.7Ft2

top coil with 26KW boiler input (26,643 btu/h) at 80*C will raise 638 liters/h (168 g/h) from 10*C -> 45*C (35*C increase = 63*F)

168 x 8.3 x 63 = 87,847 btu/h

My system requirement is small @ 24MBH @ -20*F

The circulator from DHW to RT would only create circulation within the top 1/3 of tank, not out to fixtures.
This flow around the top coil will increase heat transfer into coil.

This is the benefit: The Vitocell 100-B will act as a buffer tank for boiler and provide DHW.

Here is my plan, Burnham RV3 CI boiler will heat tank via bottom coil, under control of tank aquastat.

At my high altitude (8,800') this will create long efficient burn cycles.

My DHW will be provided by the 79 gal. contained in tank.
My 4 zone system can sip heat out of tank as required by thermostats.

As I only need about 1/3 as much heat out as what the top coil could put into tank, I think it's possible.
Have U ever heard of someone trying this?

Thanks BBP

billyboy

I found this thread:
http://forum.heatinghelp.com/discussion/comment/972759#Comment_972759

From 3rd post by Mark Eatherton

"Have you looked into some of the med large dual coil tanks like ... Amtrol has? They've got a 119 gallon dual walled dual coiled tank that works great if you can keep it from getting limed up, and I have a solution for that.

Thinking about dropping one of them into my house. Top coil is for space heating interface."

billyboy

and this thread:
http://forum.heatinghelp.com/discussion/111839/intigrating-solar-hydronic-floor-and-on-demand-heater

1st post by ALH:
"Use a dual coil 80gal DHW pre-heat tank for storage. Connect the heating system to the upper coil, solar to the lower coil."

billyboy

See Caleffi Idronics #3

http://www.caleffi.com/sites/default/files/coll_attach_file/idronics_3_0.pdf

pg26 diagram

billyboy

"The upper coil can also
extract
heat from the tank’s
water for use in space heating. With the boiler and its
circulator off, the tank circulator moves hot water from
the upper coil into the HydroLink. It is then distributed
to the active space-heating circuits."