[EnergyPlus_Support] Re: ASHRAE Equipment Capacity Sizing Factors - Different for Heating and Cooling

["jeannieboef" <jeannieboef@xxxxxxxxx>]

James, your second method was the one I was most likely to use as supporting a conservative deviation, i.e. 1.15 for heating instead of 1.25 is easy enough to document for LEED certification purposes.

Like you say, just oversizing the chiller or boiler is the obvious, but one should then oversize coils, fans and so on as well. By hand this is realistically only possible for very simple building models, and I suspect these two methods are the ones that have been used in the past.

Has anybody written an EMS to do this?

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "James V Dirkes II, PE" <jim@...> wrote:
>
> Dear Jeannie,
> 
>  
> 
> For v5,  I do it manually after getting the simulation to run by looking in
> the output for the E+ calculated sizes.  I like to use the HVACSizingSummary
> Report to find the autosized capacity, then manually size the equipment with
> the desired additional capacity.
> 
>  
> 
> Remember that when you manually size one piece of equipment, it often
> affects other equipment.  E.g.,  Sizing the chiller affects the pump, coils
> and air loops.  I have not spent much time trying to figure this out, so to
> be safe I generally autosize everything or manually size everything.  I know
> you CAN mix manual and auto sizing, but you can get problems from doing so
> also.
> 
>  
> 
> A possible shortcut is to make the Sizing:Parameters SizingFactor = 1.15
> (which affects both heating and cooling).  If the unmet load hours are below
> the maximum threshold at 1.15, I sometimes don�t bother changing the heating
> factor to 1.25
> 
>  
> 
> p.s., I am delighted to hear that v6 can do this automatically!  Thanks E+!
> 
>  
> 
> 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 Linda Lawrie
> Sent: Thursday, September 30, 2010 10:14 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: Re: [EnergyPlus_Support] ASHRAE Equipment Capacity Sizing Factors -
> Different for Heating and Cooling
> 
>  
> 
>   
> 
> one waits until V6 is released.
> 
> At 08:11 AM 9/30/2010, jeannieboef wrote:
> 
> Sizing:System, Sizing:Zone and Sizing:Parameters don't differentiat the
> sizing factor for heating (1.25) and cooling (1.15)...how does one go about
> this?
>




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