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

Thanks Linda and Drury,

I've done the simulation using DesignBuilder,and then exported the IDF file to EnergyPlus. Both gives the same results.

When you (or other people?) did simulation of Case 600 (which is available as reference), did you also find that there are differences in the heating and cooling degree days?

Thanks.
Rahmi

--- In EnergyPlus_Support@yahoogroups.com, Linda Lawrie <linda@...> wrote:
>
> We looked at this a long time ago. (2002? or earlier)
>
> And the values from Drycold.tmy to Drycold.epw
> were the same. (Actually I'm thinking the
> original drycold.tmy might have been in English
> units or needed conversion for some fields --
> whenever that happens, things can start to get
> round off errors). Or maybe not -- I do remember
> that the first attempt at conversion was from the
> tmy file to BLAST and then to EPW. That introduced some errors.
>
> Later we got the original tmy file and made the conversion.
>
> Don't forget that to compare results you may want
> to run EnergyPlus at the hour timestep rather than a 15 minute timestep.
>
> At 12:05 PM 10/22/2009, Crawley, Drury wrote:
>
>
> >The DRYCOLD.TMY should be a direct translation
> >to DRYCOLD.EPW. We only convert units where required, not the data.
> >
> >
> >----------
> >From: EnergyPlus_Support@yahoogroups.com
> >[mailto:EnergyPlus_Support@yahoogroups.com] On Behalf Of rahmiandarini
> >Sent: Thursday, October 22, 2009 1:54 PM
> >To: EnergyPlus_Support@yahoogroups.com
> >Subject: [EnergyPlus_Support] Re: Heating degree days and cooling degree days
> >
> >
> >
> >Sorry, I forgot my next question...
> >
> >When there are differences between DRYCOLD.TMY
> >and DRYCOLD.EPW, then when I simulate CASE 600,
> >it means I compare the same case but different weather data?
> >If yes, I conclude that this difference in
> >weather data is one of the factor that make my
> >results different from the reference (what's EP
> >developers have been done/provided in the literature)
> >
> >Thanks again,
> >Rahmi
> >
> >--- In
> ><mailto:EnergyPlus_Support%40yahoogroups.com>EnergyPlus_Support@yahoogroups.com,
> >"rahmiandarini" <rahmiandarini@> wrote:
> > >
> > > OK Drury,
> > >
> > > Thanks a lot for this answer.
> > > I need more clarification, the DRYCOLD.TMY is
> > provided also by ASHRAE, but why they put different 'base'? (18.3°C and 10°C)
> > >
> > > Thanks
> > > Rahmi
> > >
> > > --- In
> > <mailto:EnergyPlus_Support%40yahoogroups.com>EnergyPlus_Support@yahoogroups.com,
> > "Crawley, Drury" <Drury.Crawley@> wrote:
> > > >
> > > > 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.
> > > >
> > > > ________________________________
> > > >
> > > > From:
> > <mailto:EnergyPlus_Support%40yahoogroups.com>EnergyPlus_Support@yahoogroups.com
> > [mailto:EnergyPlus_Support@yahoogroups.com] On Behalf Of rahmiandarini
> > > > Sent: Thursday, October 22, 2009 4:42 AM
> > > > To:
> > <mailto:EnergyPlus_Support%40yahoogroups.com>EnergyPlus_Support@yahoogroups.com
> > > > 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
> > <mailto:EnergyPlus_Support%40yahoogroups.com>EnergyPlus_Support@yahoogroups.com
> > <mailto:EnergyPlus_Support%40yahoogroups.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
> > > > > >
> > > > >
> > > >
> > >
> >
> >
> >
> >
>