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A/C CALCS FOR COMMERCIAL
smoore
Member Posts: 28
Does anyone have a quick formula to size a/c for commercial applictions. I would like to use this for a quick quote and then a detailed heat loss/gain if I get the job.
thanks
thanks
0
Comments
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A/C calcs
You might try contacting mecahnical engineering firms in your aera and ask if they have a A/C average guess as to square foot loads you might use for your guess. offering to pay for the guess A/C load calc may help. It comes under the consultation idea. Most of those guys have done a lot of that, and may be willing to give up their idea for a small fee. In the mean time keep a record of all your calcs and make your own quickie guess calculator
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EVEN
Even for a quick quote, loads in commercial vary so widely based on what the space is used for I'm not sure how far I'd trust them. You could do a very simple Manual J (even though it is for residential) and try to throw in people & appliance loads then follow up with a good Manual N if you get the job.0 -
AMEN
And don't forget lighting! Easily thousands of watts of incandescent (typically halogen) lighting in a not particularly large retail space where products (not boxes) are shown.0 -
Very rough
Rule of thumb for here in Michigan. 1 ton per 400 sq ft. plus 150 btu's per person, plus wattage of lighting. (wattage X 3.1 = btu's)
Again this is very rough and can be high as easily as low. Either way you are burned because the customer will hold you to your first "guesstimate" 9 times out of 10. Take the time to do it right.0 -
Be Careful
Almost every commercial building has some sort of ventilation. Usually by code 20 cfm per person, plus any mechanical exhaust.
This can throw off calcs in a big way very fast.
Just 1,000 CFM's of ventilation can increase a heat gain by almost 2 tons, and thats just to cover 50 people.
kf
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calcs
400 cfm per ton is used a lot in N.E. but its only a rule.
depends on the space,to much internal gain to guess,computers,coolers, kit areas have refrig,ect.
Jewelry stores will kill you with lighting loads 3.41BTU'sper watt.people as much as 300 BTU's per person, fresh are requirements.Solar gain....good luck
steve0 -
commercial load calculation
HVAC Equations, Data and Rules of Thumb By Arthur A. Bell Jr. is a great source for a quick estimate. Amazon.com for about $60.000 -
load calc
for new construction 2x6 walls 500 sq. feet per ton. for existing marginal insulation lots of windows 375 sq. feet per ton.0 -
News?
So did you get the job?
What factor did you use for capacity?
What part of the world is the project in?0
This discussion has been closed.
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