Heating and cool loads analyse

[chunky2k]

Good morning, 

i have an HVAC question regarding the Analyze in Revit

as i click on the analyse, choose for example (school or uni), then choose the "location" ( i choose Abu dhabi on the search)

but when i see the weather, i find the option as the "dry bulb" and theses number

as far as i know these options are done in cooling water "chiller" 

what am looing for is to do the calculation for the Ducted units (FCU) and the package units, (Gas R22) units

and when the result came out to life, it was not as expected

in UAE in a nominal calculation for a room of (7X7.2) we got in a normal result of cooling of 50.4 TMBH and since it is a class room we can add extra tonnage to that, for example we make it 60 TMBH, the 60 TMBH give us around 2000 CFM

but in the program it gave me the result of 1246 CFM, which i guess it is very low, and for sure this is done for the Chiller calculations

do you know how can i make the calculations for DX system (Ducted and package units)

best regards

[HVAC-Novice]

I don't know what to do with your specific problem. But in general Revit gives very rudimentary values and isn't really good in dealing with specific equipment.

I also noticed many errors in the R-values of assemblies in Revit. I wouldn't trust it beyond schematic design. For actual HVAC load and design you should use a software that is dedicated to that, like Trane Trace. You can export the spaces as gbXML and import into Trace or other software to get the room dimensions.

In Trace you also get detailed reports to check. It happens so easily that one thing is wrong and all numbers are off and Revit doesn't give you the tools to analyze that. You also will need the block load, not just add the single zone loads.

Revit is really great, but you need to know its limitations and load calculations are very limited for actual design. Schematic design, yes.

Also how do you analyze if you rather have chilled water temp of 40°F or 44°F, if you pit chillers in series or parallel, if you oversize DX coils, etc.... this all only can be done with a dedicated software.

I didn't check if 2014 improved in that area, but I didn't hear of that. Trust me, once Revit can do all that I'm the first one to cancel subscription on the other software.