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



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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