[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [EnergyPlus_Support] EXTENDED DOUBT: reg:indian weather data
I am writing to the group as it may contain some useful information for other users too.
For MRM model, you may look into a book "Solar radiation and daylioght models" by T Muneer (Architectural Press).
TRY and TMY are different. I had explained in previous mail that hour by hour values cannot be compared as weather data sets were developed using long- term statistical properties of the available time seeries.
The data given in Mani's books is basd on measured data between 1930 and 1960, and moreover the radiation data in Mani's book is also modeled. For your information, solar radiation is measured in India by the Meteorological Department only at about a dozen locations, and that too is not easily available. The radiation data therefore has to be modeled. I emphasise once again that it makes no sense to compare hour by hour data from two different sources as both are statistically modeled data sets.
I hope this takes care of your doubts. But feel free to ask as and when more doubts come up.
Best regards,
Anil Misra
RAJ KUMAR <srajk76@xxxxxxxxx> wrote:
dear sir,
Thanks for clarifying my doubt, i have some more doubt in weather data
are TMY and TRY, same terminology or different?. Did the data has been formulated based on steps given in TMY2 manual?. Could you please explain about MRM model or give me some reference?. Is The solar radiation data provided, instantaneous or average?.
Because I have taken monthly mean hourly radiation from EPW and compared with Solar radiation handbook by Mani, it is not matching.
There will be variation, I accept.But say for 0700 HRS (LST) in january, if the radiation given in handbook is 40 KWhr/m^2 and 100 in EPW. This makes as to think, why? . The data given in Mani handbook is average Solar radiation.
At the same, time, if I take average Solar radiation on hourly basis, it matches with handbook data having 10-20% variation.
Regards,
Rajkumar.S
A Misra <lesolarch@xxxxxxxxx> wrote:
The Indian weather data was sent to EnergyPlus in form of Typical Reference Years (TRYs) which were generated from actual measured data series from 1981 to 1992 (except radiation which was synthesized on the basis on MRM model). EP later converted the data to EPW format. The development of TRYs is based on long term statistical averages of Dry-Bulb temperatures. During this process there is no control on the year from which data has been extracted. This decision was made automatically by the statistical averages. I would suggest that data must be accepted as statistical representative of long- term characteristics of weather at the particular site/location. Therefore the data cannot be compared with any actual measured data for a particular day or hour at a given location.
I would be happy to answer further quereis on this matter, if any.
Best regards,
Anil Misra
New Delhi, India
---------------------------------
Relax. Yahoo! Mail virus scanning helps detect nasty viruses!
[Non-text portions of this message have been removed]
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.idf and press the "search" button.
SPONSORED LINKS
Medical software program Cad software program Email software program Wedding program software Backup software program Anti virus software program
---------------------------------
YAHOO! GROUPS LINKS
Visit your group "EnergyPlus_Support" on the web.
To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
---------------------------------
---------------------------------
Yahoo! Mail
Use Photomail to share photos without annoying attachments.
[Non-text portions of this message have been removed]
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.idf and press the "search" button.
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/EnergyPlus_Support/
<*> 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/