RE: [EnergyPlus_Support] Re: Heating degree days and cooling degree days

["Crawley, Drury" <Drury.Crawley@xxxxxxxxxx>]

ASHRAE Standard 90.1 uses a base of 10C for cooling degree days.  That is often the point at which a commercial building requires some sort of cooling because of internal loads such as computers or other equipment.  This cooling can be either by natural means -- natural ventilation, economizer -- or by cooling equipment.

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From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of rahmiandarini
Sent: Thursday, October 22, 2009 4:42 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: Heating degree days and cooling degree days

 

Yes, I know that.
But, why, for cooling, EP uses 'base' of 10°C?
Does it means that when the outside air temperature is 15°C, then cooling is required??

Thanks

--- In EnergyPlus_Support@yahoogroups.com, Don Shirey <shirey@...> wrote:
>
> Notice that the "base" is different (18.3C vs 18C vs 10C).
>
>
> rahmiandarini wrote:
> > Hi,
> >
> > I have question regarding weather data of DRYCOLD.TMY, provided for simulation of case 600, ANSI/ASHRAE Standard 140-2004.
> > I have converted the weather so that i can use the simulation in DesignBuilder & EnergyPlus.
> > When I checked the documentatio of ANSI/ASHRAE Standard, it is mentioned :
> > Heating degree-days (Base 18.3°C) : 3636.2°C - days
> > Cooling degree-days (Base 18.3°C) : 487.1°C - days
> >
> > and in the DesignBuilder
> >
> > Heating degree-days (Base 18°C) : 3379.2°C - days
> > Cooling degree-days (Base 10°C) : 1446°C - days
> >
> > and my question is that, what does it means, and why those values are difference as they're originally from the same data.
> >
> > Thanks,
> > Rahmi
> >
>

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