the 2 to 2.5 times cooling load in Atlanta is based on "Refrigeration & Air Conditioning Technology 5th ed"
I'm sure they're smarter than anyone on this post(execpt me).
I also be my salary is well over 3 times yours abby :)
Abby,
almost everyday.
If a 3 ton HP can provide 24k btu/hr of heat on a 10 degree day, the rest has to be made up in auxillary heat.
Think about it -- during the Summer the difference between ambient and indoor is around 20 degrees -- what is the difference between 70 degrees indoor & a cold...
RossABQ,
GM offered me an Engineering Mgmt positon that was in charge of the manufacturing engineering & tool/diemaking dept for 125k with a Bachelors in 2000 -- but I had proven mgmt & engineering background.
gepman,
That's oldschool. I was a maintenance machinist for Wyman-Gordon(Fortune 400 firm) back in 79 and I got paid union wage of 37k doing maintenance on Absorption Chillers.
Engineers always were underpaid.
NASA rocks in that you start at G 13, but your making 100k within 10 years with a...
Forgot to mention another rule of thumb:
Heating load in the Southeast is approximently 2.5 times cooling load. So if you assume 3 tons for 1800sf home in Atlanta, assume your heating load will be around 90k btu/hr.
Rules of thumbs are just a guideline -- they're nice to compare your...
Depends whether it's Ashville or Wilmington -- be careful that you select proper sequencing of the strip heat and capacity.
Contractors in NW Florida use 600sf/ton, so if your east of the hills, I quess around 700sf/ton without doing a load calculation.
I use a Fluke 52 II with bead probes -- awesome field thermometer.
Cold ambient will slow response, that's why you have to keep the unit in an insulated case when taking LT & MT refrigerant superheats.
ChrisConley,
well they don't call it "architorture" at GT for nothing.
The biggest complaint I see from PEs & Goverment Inspectors is that the architects draw up plans that show a poor understanding of HVACR principles -- duct routing, etc.
I like the idea that architects take the liability...
omg -- I gave the gentleman a 10% parameter that PE's use --it's just a guideline.
I just wanted to state that I think Autocad's MEP software sucks, but it's what architects & engineers seem to use.
gepman,
No I can't without researching.
But I would suggest Igresson verify & persue the possibilities -- I'm confident a 3 ton 2 stage comp with VSD fans will offer this gentleman what he's looking for for certification.
He just has to be diligent in his verification & reasoning,
With a VSD HP, it is better to size for 3 ton.
The 3 ton VSD HP will not only draw the same current as the 2.5 ton HP at lower capacities but also offer higer heat load capacity at lower temperatures.
CountOlaf,
I assumed the poster used Autocad's MEP(mechanical/electrical/plumbing) software in his design venture and not about mechanical/electrical/plumbing design.
Wouldn't be surprised tlhoo uses Autocad MEP.
I'm hearing around 10% from licensed PE's.
I'm not too excited about using MEP -- very poor parametric modeler and export to CAE programs, but it doesn't make sense to go against the grain with Architects, etc.
To summarize that paper:
The only time flex came close to galv steel was fully extended and there was considerable loses when at 94% efficiency, which is extremely rare (i've never seen it) in the field.
Expect to see flex duct losses approaching 50% compared to galv metal; in addition, expect...
Condensing temps for lower seer units based on ARI standards:
7 to 10.5 seer -- 25 to 30 deg
10.5 to 11.9 seer -- 20 to 25 deg
12 & up seer -- 15 to 20 deg.
These are the numbers I use in the field in engineering & contracting for diagnosing hvacr problems.
Very difficult to get below 15...
