using monitored solar radiation data

[katerinaF]

I am using a file with hourly solar radiation values of one month (I got this from five minute measured data at the site) from Southampton (uk). I formated the file to the format that the PVsyst needs (ASCII text file) and I used the tools/import ASCII meteo file facility to import the data. (I tried to attach the file that I used in this e-mail but it does not allow me to do so-why?). The conversion is succesful, but I am geting the message:

"The meteo values are shifted by 81 minutes by respect to the Time defined in the time zone of your site. Please redefine the record time label in the format protocol, or adjust the time zone of the reference site."

I tried (I think) all these. I changed the time shft to 30 minutes in the time label in the format protocole and I still had the same message when I tried the conversion again. Then I changed the time zone of the "geographic site"/open in the software and I still had the same message. Then I changed the time zone and the time shift in the file with the monitored data that I wanted to import (time zone zero now and time shift 30). It still shows me the same message (do they have to be chcanged in the file as well?).

Could you please help me with this?

Many thanks,

K.

The fle is as shown below in the extract.

#Measured data

#Sitename; Southampton

#Country; UK

#Data Source; Lancaster Building STAR facility

#Timestep; Hour

#Year; 2001

#Latitude; 50.95

#Longitude; 1.36

#Altitude; 3

#Time Zone; 0

#Time Shift; 30

#Plane tilt; 50

#Plane azimuth; 0

#Albedo; 0.2

Year Month Day HHMM Tamb GHI

C Whs/m2

2001 1 1 0 -99 0

2001 1 1 1 -99 0

2001 1 1 2 -99 0

2001 1 1 3 -99 0

2001 1 1 4 -99 0.004166667

2001 1 1 5 -99 0.09375

2001 1 1 6 -99 2.74875

2001 1 1 7 -99 33.9865

2001 1 1 8 -99 103.07

2001 1 1 9 -99 113.8235

2001 1 1 10 -99 69.93333333

2001 1 1 11 -99 40.83733333

2001 1 1 12 -99 28.24133333

2001 1 1 13 -99 8.364666667

2001 1 1 14 -99 2.45675

2001 1 1 15 -99 0.029166667

2001 1 1 16 -99 0

2001 1 1 17 -99 0.016666667

2001 1 1 18 -99 0

2001 1 1 19 -99 0.001666667

2001 1 1 20 -99 0

2001 1 1 21 -99 0

2001 1 1 22 -99 0

2001 1 1 23 -99 0

2001 1 2 0 -99 0.004166667

2001 1 2 1 -99 0

2001 1 2 2 -99 0.00375

2001 1 2 3 -99 0

2001 1 2 4 -99 0

2001 1 2 5 -99 0.1725

2001 1 2 6 -99 3.2315

2001 1 2 7 -99 6.23875

2001 1 2 8 -99 38.40816667

2001 1 2 9 -99 85.44441667

2001 1 2 10 -99 87.39666667

2001 1 2 11 -99 59.32933333

2001 1 2 12 -99 48.01033333

2001 1 2 13 -99 23.45666667

2001 1 2 14 -99 2.994

2001 1 2 15 -99 0.04375

[André Mermoud]

There is necessarily a combination of Time zone definition and time shift which should match the internal time of PVsyst. This is defined as the beginning of the interval (8:00 means the period of 8:00 to 9:00).

If you have constructed an hourly file from 5 min data, you can define the hours in this way, and therefore the time shift should be 0 (you have put 30 min).

You can also change the time stamps of you data (i.e. just shift the column of hours by one hour - i.e. one cell).

You have specified GHI (Global Horizontal) irradiances, when you have defined a plane of 50° tilt: is your irradiance measured with a solarimeter in this plane ? In this case you shoud define GPI (Global plane Irradiance, or POA), and not GHI, so that PVsyst understands that this is an irradiance oin a tilted plane.

But this is not the best suited tool for importing your data: the "standard format" of PVsyst is meant for representing a full year of clean data (i.e. from "official" database").

You should use "Tools" / "Import ASCII meteo files" instead, which accepts almost any format of data.

When in this tool you press F1 for getting the procedure.

This tool will accept your 5-minutes data as such, and gather them into hourly data in a clean way.

It will also create a file just matching your data (i.e. one month, up to one day, accepting holes, an so on), without the necessity of defining dummy values.

And as you don't avail of temperatures, it will manage the generation of temperatures, on the basis of externally specified monthly values.

Please carefully read the Help "Geographical and Meteorological data > Import of hourly data ASCII files" and "Geographical and Meteorological data > Import of custom hourly data ASCII files > Conversion protocol".

[katerinaF]

Thanks for the reply. I am refering again to the same topic.

I used "Tools" / "Import ASCII meteo files" and I used the five minute data files for the PVsyst to gather them into hourly data in a clean way as suggested.

I have two questions:

1) In this case my five minute file has data of horizontal radiation. In the "Characteristics of meteo hourly files window I choose the parameters Horiz Global and Global Tilted plane and I click on the "Table" to see the values, then I click on the "Change plane" tab and I set the inlcination at 50 degrees. My question is: the values shown on the table for the parameter "Global Tilted plane" do they come from the conversion of my ON MY OWN imported values of the horizontal radiation to the 50 degrees tilted values?

2)I now import a different file where I have 5 minute measured data on 50 degrees tilted plane. Before asking for the conversion, I set the plane to be 50 degrees. Again, after the converrsion, I choose the parameters Horiz Global and Global Tilted plane and I click on the "Table" to see the values. Then, if I click on the "Change plane" tab, I notice that the setting shown there is 30 degrees although I had set it to 50 degrees for the conversion as I mentioned before. My question is: In order to see my converted imported file into hourly data on the 50 degrees inclination do I have to change this setting to 50 there?

thanks,

k