Re: [EnergyPlus_Support] Re: Weather file of College Station

Hello Mr Cris;

As the DNI decrease, the diffuse increase. So I checked the weather data & find that is the case, so many thanks for the explaination, this expalins for me why the DNI is lower in June than in January. Appreciated so much'

But still there is a point!

Why June still have minimum global ( DNI & diffuse) than May & July. There is a drop in the total solar radiation in June specifically. As the month before it & the month after it both have higher global radiation.

Monthly Statistics for Solar Radiation (Direct Normal, Diffuse, Global Horizontal) Wh/mÂ²
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Direct Avg 4311 4089 4543 4656 4756 3564 4865 4942 4264 2758 2725 4440

Direct Max 8349 7801 8952 10104 8570 7584 8939 8220 7941 7467 7124 7395
Day 19 23 28 21 19 20 26 9 6 16 9 30

Diffuse Avg 928 1376 1665 1831 2703 2531 2756 2191 1876 1541 1076 985

Global Avg 2893 3584 4493 5028 6127 5182 6199 5724 4671 3096 2408 2938

I wonder if there is an explaination for that

Thank you very much

Eman Tora

From: Chris Gueymard <chris@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sent: Fri, November 6, 2009 1:25:25 PM
Subject: [EnergyPlus_Support] Re: Weather file of College Station - Texas

Units are obviously Wh/m2 per day on a monthly-average basis.

The reason why DNI is lower in summer there (as at many other locations)
is because of a higher turbidity, higher humidity, and higher cloudiness.

Chris

>
> Hello
>
>
> To find the direct normal solar radiation for
> College Station, TX, I went to the following web site:
> http://www.eere. energy.gov/ buildings/ energyplus/ cfm/weather_ data.cfm
> Then, I chose the country, the state, the city
> then clicked on the Stat tab and get solar data. Here is what I got:
> Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
>
> 4311 4089 4543 4656 4756 3564 4865 4942 4264 2758 2725 4440
>
> I have a question:The trend for the DNI does not seem to make much sense to me. How can June
> be 3564 and January be higher 4311.
> Your input will be greatly appreciated.
> Many thanks.
> E. Tora
>

--
Chris A. Gueymard, PhD
Solar Consulting Services
P.O. Box 392
Colebrook, NH 03576, USA
Tel. (603) 237-8550
Fax (603) 237-5314
http://www.solarcon sultingservices. com

Re: [EnergyPlus_Support] Re: Weather file of College Station - Texas