Re: [EnergyPlus_Support] Re: Site:WeatherStation profiles.

Thank you for your feedback.
I could NOT set in the Site:HeightVariation object the field called Wind Speed Profile Boundary Layer Thickness to 0. I got the following error:
** Severe ** Out of range value Numeric Field#2 (Wind Speed Profile Boundary Layer Thickness), value=0.00000, range={>0.0}, in SITE:HEIGHTVARIATION

I set it to 470 like in the Site:WeatherStation object, results are similar with and without Site:HeightVariation.

Jose

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Griffith, Brent" <brent.griffith@...> wrote:
>
> I depends if your z values for the model geometry are relative to the roof of the 6 story building or to the ground. The weather station is really at a height of 2 m plus 6 stories.
>
> It sounds like you may want to just turn off the profile model so the model uses the direct values from the weather station. In the Site:HeightVariation object, set the fields called Wind Speed Profile Boundary Layer Thickness and Air Temperature Gradient Coefficient to zero.
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of joselecastro
> Sent: Friday, April 19, 2013 1:11 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Re: Site:WeatherStation profiles.
>
>
>
> But standard conditions are:
> - Air temperature is measured at 1.5m
> - Wind speed is measured at 10m above ground
> - Weather station is in a flat, open field with little protection form the wind.
>
> If I do not include Site:WeatherStation, Energy Plus will understand that the wind speed is at 10m when in fact it is at 2m, and that weather station is in open field with little protection when it is in the city and a bit protected.
>
> And for the moment I use the the default exponent and boundary layer thickness for city.
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx <mailto:EnergyPlus_Support%40yahoogroups.com>, Joe Huang <YJHuang@<mailto:YJHuang@>> wrote:
> >
> > The only purpose of the wind profile exponent is to adjust the wind speeds to that at the
> > actual building site. If you have a weather station right at the site and are using those
> > measured wind speeds, I don't see the benefit of making any adjustments, unless there's a
> > significant difference in height between your weather station and model building. Lastly,
> > keep in mind that these exponential wind profiles are gross generalizations of typical
> > conditions. For a specific site, especially one in an urban setting as yours, it may not
> > apply at all for a small height difference as 2 m.
> >
> > Please excuse me if I'm misunderstood what you're trying to do.
> >
> > Joe
> >
> > Joe Huang
> > White Box Technologies, Inc.
> > 346 Rheem Blvd., Suite 108D
> > Moraga CA 94556
> > yjhuang@
> > www.whiteboxtechnologies.com<http://www.whiteboxtechnologies.com>
> > (o) (925)388-0265
> > (c) (510)928-2683
> > "building energy simulations at your fingertips"
> >
> >
> > On 4/17/2013 9:28 PM, joselecastro wrote:
> > >
> > >
> > > Thank you for your reply Joe.
> > > Yes, with city or urban exponent and boundary layer thickness I got similar results, I
> > > think not with open country but it is not the case.
> > > Like my weather station is 2m height in the city I may use Site:WeatherStation, because
> > > standard conditions are wind speed is measured at 10m and in a flat open field with
> > > little protection from the wind.
> > >
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx <mailto:EnergyPlus_Support%40yahoogroups.com> <mailto:EnergyPlus_Support%40yahoogroups.com>,
> > > Joe Huang <YJHuang@> wrote:
> > > >
> > > > If you are using the wind speeds from your weather station that's nearby and has the same
> > > > elevation, the wind speed profile exponent and boundary layer thickness have no effect,
> > > > although you could still input them if you want. These only come into effect when the
> > > > elevation of your site differs substantially from that of the weather station.
> > > >
> > > > Joe
> > > >
> > > > Joe Huang
> > > > White Box Technologies, Inc.
> > > > 346 Rheem Blvd., Suite 108D
> > > > Moraga CA 94556
> > > > yjhuang@
> > > > www.whiteboxtechnologies.com<http://www.whiteboxtechnologies.com>
> > > > (o) (925)388-0265
> > > > (c) (510)928-2683
> > > > "building energy simulations at your fingertips"
> > > >
> > > >
> > > > On 4/16/2013 10:12 PM, joselecastro wrote:
> > > > >
> > > > > Hi All,
> > > > >
> > > > > I built a small scale building on the roof of a six story building. My weather station
> > > > > is located near the small scale building. I need to use Site:WeatherStation to compare
> > > > > simulations and measurements.
> > > > >
> > > > > Like it is located in the city, should I use 0.33 as wind speed profile exponent and
> > > 460
> > > > > as wind speed profile boundary layer thickness ?
> > > > >
> > > > > Does anyone have experience using a weather station and simulating?
> > > > >
> > > > > Thank you very much,
> > > > > Jose
> > > > >
> > > > >
> > > >
> > >
> > >
> >
>