Help to decide multiple choice for Air Distribution!!!
Help to decide multiple choice for Air Distribution!!!
(OP)
I have a warehouse building in this space:
L= 108.75 FT
W= 80 FT
H Wall= 19 FT
H Susp. Roof = 10 FT
Area Floor= 8700SFT
Vol. Fan Level= 165300 CFT
Vol. Susp. Roof= 43500 CFT
Space below 14' Temp. = 55-65F
Space Above 14' Temp. = 65-71F
Differential Temp. = 10F
Hot Water Supply = 160F
Hot Water Return = 150F
Boiler = 160F
We are losing Heat from floor to 14'. Our Return Air Louver is at on top at 22'H and our Supply Duct is at approx. 20'H. Apparently there is a short circulation due to stratification and shorter cycle. There are several options:
A) Lower the Return Air Louver to about 3'H above floor, and increase Boiler Capacity since Boiler only operates at 160F while Design indicates 180F.
B) Purchase 2 new Fans at 16' blades @ cost = $4000 ea. from Big Ass Fans to de-stratify.
C) Rearrange Air Distribution by lowering diffusers to about 3-5' and lower the Return Air Louver to about 3'H above floor.
I think option A) is the best but I don't know if Energy cost to crank boiler up to 20F would be the energy cost issues. Please consult. Thank you!
L= 108.75 FT
W= 80 FT
H Wall= 19 FT
H Susp. Roof = 10 FT
Area Floor= 8700SFT
Vol. Fan Level= 165300 CFT
Vol. Susp. Roof= 43500 CFT
Space below 14' Temp. = 55-65F
Space Above 14' Temp. = 65-71F
Differential Temp. = 10F
Hot Water Supply = 160F
Hot Water Return = 150F
Boiler = 160F
We are losing Heat from floor to 14'. Our Return Air Louver is at on top at 22'H and our Supply Duct is at approx. 20'H. Apparently there is a short circulation due to stratification and shorter cycle. There are several options:
A) Lower the Return Air Louver to about 3'H above floor, and increase Boiler Capacity since Boiler only operates at 160F while Design indicates 180F.
B) Purchase 2 new Fans at 16' blades @ cost = $4000 ea. from Big Ass Fans to de-stratify.
C) Rearrange Air Distribution by lowering diffusers to about 3-5' and lower the Return Air Louver to about 3'H above floor.
I think option A) is the best but I don't know if Energy cost to crank boiler up to 20F would be the energy cost issues. Please consult. Thank you!





RE: Help to decide multiple choice for Air Distribution!!!
The anti-stratification fans are perhaps the cheapest way to go. Rather than two huge "Big Ass" fans at $4,000 what about 6 or 8 of the commercial grade fans at $100 each?
Diffusers are not designed to get air (or heat) down. They are specifically designed to move the air, horizontally, across a ceiling (typically) such that the air hugs the ceiling (the so called Coanda effect) and entrains room air into the primary airstream and hence does not create drafts. Since you don't have a ceiling you won't quite get the full effect but either way, for the most part diffusers distribute air horizontally which is not what you want. Install some grilles or diffusers which are specifically designed (and adjustable) to squirt the air down (nozzles?).
Dropping the RA grille(s) to low level would also help a lot.
RE: Help to decide multiple choice for Air Distribution!!!
RE: Help to decide multiple choice for Air Distribution!!!
RE: Help to decide multiple choice for Air Distribution!!!
You mention increasing the boiler capacity and increasing the discharge water temperature to 180, that will only work if you also maintain the return temperature at 150 by increasing flow, adding/changing the pump.
If you do that, you'd want to take a look at all of the coils and heat exchangers on the loop to see what 180/150 will do with them.
RE: Help to decide multiple choice for Air Distribution!!!
I figure out the problem was residue in the fire tube. Sensors at the pilot tube. We fix that and it seems to work alright. Thank you so much. I am ready to post my next question on necessary to use the plate heat exchanger, if you have time, please help.