[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[EnergyPlus_Support] Re: winter design day

Jerry,

Without checking E+ docs, but using my experience......
A "design day" is a "worst case" condition.  For winter, that means a sustained cold period with no sun and no internal heat (e.g., lights or PCs).  Using a zero degree daily range is a fairly normal approach to those criteria.
A practical example in Michigan, where I'm from, would be an extended weekend (say, Christmas) when the temps drop very low and stay there for hours on end.  The sun, as is usual in MI, doesn't shine.  (Of course it could also be night time.  We're why light therapy got popular.
In that instance, the heating system is all you've got; it better be big enough!

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Jerry McManus" <jerrymcm@...> wrote:
>
> Hi Folks,
> 
> I'm new to EnergyPlus, and a total noob when it comes to HVAC, so please be gentle!  Here's my first newbie question:
> 
> While learning about design days I was confused by the fact that all of the winter design days in the example weather data have a 0 daily temperature range modifier.  Searching the input\output reference yielded this note:
> 
> "Note that usual Winter design conditions are for very cloudy days (clearness = 0), and low temperatures (temperature range=0)."
> 
> Unfortunately no explanation is given why low temperatures should have 0 for the daily temperature range...?  This is one of those things that is probably obvious to an HVAC pro, but it's not at all clear to me why a winter design day should not bother with highs and lows in the temperature range.
> 
> Any help will be greatly appreciated.  Thanks!
>




------------------------------------

The primary EnergyPlus web site is found at:
http://www.energyplus.gov

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/

Attachments are not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/join
    (Yahoo! ID required)

<*> To change settings via email:
    mailto:EnergyPlus_Support-digest@xxxxxxxxxxxxxxx 
    mailto:EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
    EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/