[EnergyPlus_Support] Re: Warning Message: air volume flow per cooling capacity out of range

["bcmcgr" <bcmcgr@xxxxxxxxx>]

That's what I'm finding as well.

Do either of you know if LEED will accept my model with the Proposed case's heating and cooling capacities being autosized?

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "James V Dirkes II, PE" <jim@...> wrote:
>
> Brendan,
> 
>  
> 
> E+ has limits for flow / Watt which show up in the .err file.  I think they
> vary a bit depending on the coil, but generally flow / Watt must be:
> 
>  
> 
> >0.00004027 and <0.00006041
> 
>  
> 
> The Building Performance Team
> James V. Dirkes II, P.E., LEED AP
> 1631 Acacia Drive NW
> Grand Rapids, MI 49504
> 616 450 8653
> 
>  
> 
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of bcmcgr
> Sent: Thursday, February 10, 2011 9:26 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Re: Warning Message: air volume flow per
> cooling capacity out of range
> 
>  
> 
>   
> 
> Thank you both for your prompt help. It is definitely appreciated.
> 
> Can either of you explain to me how you "ensure that the maximum supply flow
> is changed accordingly". I can definitely change the max to design
> conditions but I'm not sure how to do this in either E+ or DB.
> 
> Thanks again.
> 
> Brendan
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com> , "James V Dirkes II, PE"
> <jim@> wrote:
> >
> > Dear Brendan,
> > 
> > 
> > 
> > The airflow / watt warning is a common one for me, also, for manually
> sized
> > systems.
> > 
> > 
> > 
> > I have not tried it yet, but the E+ Help desk suggested that I put two
> coils
> > in series to eliminate the warning. This effectively will leave the
> airflow
> > the same but cuts the coil capacity in half for each coil. it might work!
> > 
> > 
> > 
> > p.s., This fix will probably not significantly affect your results unless
> > you have accurate part load curve information for your coils. If you DO
> > have that information, you may be able to cobble some part load
> coefficients
> > (different for each coil) that will do the trick.
> > 
> > 
> > 
> > The Building Performance Team
> > James V. Dirkes II, P.E., LEED AP
> > 1631 Acacia Drive NW
> > Grand Rapids, MI 49504
> > 616 450 8653
> > 
> > 
> > 
> > From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com> 
> > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com> ] On Behalf Of bcmcgr
> > Sent: Wednesday, February 09, 2011 2:15 PM
> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com> 
> > Subject: [EnergyPlus_Support] Warning Message: air volume flow per cooling
> > capacity out of range
> > 
> > 
> > 
> > 
> > 
> > "Rated air volume flow rate per watt of rated total cooling capacity is
> out
> > of range."
> > 
> > I'm working on a LEED project using Design Builder and my Proposed model
> > gets the above "Severe Error" when the model is run in E+. I can get
> around
> > this by having Design Builder "autosize" my HVAC system but then when I
> > check the HVAC system sizing output from E+ my sizes (capacities) are much
> > less than the actual design. 
> > 
> > It's important to note here that I'm modeling the minimum ventilation
> > (outside air) per ASHRAE 62.1 (ie per person and per area) which is much
> > smaller than the capabilities of the system. 
> > 
> > Has anyone encountered this in the past? Should I just submit the model as
> > if it's autosized? 
> > 
> > And, of course, I'm being rushed to submit by Friday. Any help on this is
> > much appreciated.
> > 
> > Thanks in advance. 
> > 
> > Brendan
> >
>




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