Town Garage/ Coal Boiler Project

 
ScottB
Member
Posts: 46
Joined: Wed. Nov. 01, 2017 2:53 pm
Stoker Coal Boiler: Van Wert VA 400 DF
Coal Size/Type: Buck
Other Heating: Jotul wood stove

Post by ScottB » Mon. Dec. 11, 2017 8:37 am

Rob- Very helpful explanations of pickup and performance/cost trade offs when deciding on water temp an radiation surface area.

Pacowy- My mistake, pickup was allowed for in step 4.

CapeCoaler- Good suggestion on contacting Uponor regarding this specific application. They should know of implementations similar to ours.
I had initially used the same air infiltration assumptions as used in the Uponor's Complete Design Assistance Manual (CDAM) examples, .35 air exchanges per hour, when computing heat loss in the new garage section, assuming the application of perimeter floor radiant heating. This resulted in what I now think was an unrealistically low heat loss value for that garage section, and the total combined building heat low values that I mentioned in a previous post ( 280k to 340k btu/hr). Setting the # of air exchanges to 1.2 for the new garage, pushes the air infiltration losses alone to ~200k btu/hr, and a total combined building heat loss to just under 500K. At this level, the Van Wert VA2400 seems to be the only single boiler in this range that I know of, with the Van Wert VA4000 or AHS 1000 also easily able to meet the load requirement. My codes person is advising me not to use a single 1M or greater input BTU boiler if possible, due to EPA rules. I am starting to think that the two boiler option has to be seriously considered due to availability. Rob's suggestion of exercising our oil furnace during extra high heat load days also may play a role in this implementation.

Overall, as soon as I gain confidence in the air infiltration numbers for the garage sections, heat exchange in old garage and radiant design in new garage can be defined to work back to boiler sizing. At this point I am comfortable with the office portion since my numbers match up well with the currently installed propane heating capacity.


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