Good Morning, eQUESTers,
I'm working on my design case model. Here's my ATTN report:
**WARNING**********************************************************************
SYSTEM EL1 Sys1 (PSZ) (G.NNW1) may have inadequate cooling capability
Check COOLING-CAPACITY and MIN-SUPPLY-T for consistency
**WARNING**********************************************************************
SYSTEM EL1 Sys2 (PSZ) (G.WSW2) may have inadequate cooling capability
Check COOLING-CAPACITY and MIN-SUPPLY-T for consistency
**WARNING**********************************************************************
SYSTEM EL1 Sys3 (PSZ) (G.N3) may have inadequate cooling capability
Check COOLING-CAPACITY and MIN-SUPPLY-T for consistency
**WARNING**********************************************************************
SYSTEM EL1 Sys4 (PSZ) (G.S4) may have inadequate cooling capability
Check COOLING-CAPACITY and MIN-SUPPLY-T for consistency
**WARNING**********************************************************************
SYSTEM EL1 Sys5 (PSZ) (G.N5) may have inadequate cooling capability
Check COOLING-CAPACITY and MIN-SUPPLY-T for consistency
**WARNING**********************************************************************
SYSTEM EL1 Sys6 (PSZ) (G.E6) may have inadequate cooling capability
Check COOLING-CAPACITY and MIN-SUPPLY-T for consistency
**WARNING**********************************************************************
SYSTEM EL1 Sys7 (PSZ) (G.C7) has zero outside air for design calculations
This last one I can answer as this system is a R/A only computer room cooler. For the others:
COOLING-CAPACITY comes directly from the HVAC designer and is the capacity of the installed units. I've tried adjusting MIN-SUPPLY-T from 55 to 50 (and this seems to jive with information the coil manufacturer provides) to get a larger delta-T and it only seemed to make things worse somehow. Minimum OSA is 20%, but again, this is a design condition. These units do have enthalpy-controlled economizers.
I'm also getting WAY too many hours outside of throttling range - 15%. My baseline model only has a 3%. I'm way out of whack with Appendix G requirements.
Any suggestions as to settings to modify to clear these? Thank you!
MARK DARRALL, AIA, LEED AP BD+C, NCARB
