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RE: [EnergyPlus_Support] About Meteonorm and EPW files
Daniel,
We can run some experiments if you like. In Meteonorm there are two options for Temperature (1961-1990 or 1996-2005) and two for Solar Radiation (1981-1990 or 1981-2000). Other options include selecting a different radiation model (Perez, Hay, Gueymard, or Skarveit/Osleth), Radiation model (Default-hour, Minute, Clear Sky Radiation), Temperature model (Default-hour or 10-year extreme-hour). You can also set the monthly values to the minimum, mean or maximum values.
For the files that are posted on the E+ YahooGroup, we use: Temperature (1996-2005), Solar Radiation (1981-2000), Radiation Model (Perez), Radiation model (default-hour), Temperature model (default-hour), and the monthly values are left to mean.
The EPWs from the US are generally TMY2 files with a period of record of 1961-1990. There is work under way to use the last 15 years of data to create new US files but it has not started yet. For the EPW files in Mexico, these are IWEC, which roughly have a period of record of 1982-1999--the only data available at the time. ASHRAE is working on a project to create 2500+ new weather files using a period of record of 1982-2006. That should be done later this year.
Contact me directly if you want me to create some variations on the Meteonorm files.
Dru
________________________________
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Daniel Solís
Sent: Wednesday, January 23, 2008 1:14 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] About Meteonorm and EPW files
Hi E+
In the AAA_ReadMeFirst.txt says "Meteonorm extrapolates hourly data
from statistical data for a location. Where statistical data aren't
available, Meteonorm interpolates from other nearby sites".
In México, I found only 3 EPW files, so I downloaded those created by
meteonorm, and then compared the .stat with the "normales
meteorológicas", which are files that contain statistical data for
many cities in the country (average, maximum and minimum temperatures
averaged over 30 years and presented month by month; main cities also
have relative humidity and other stuff). It seemed logical to me that
metenorm uses the data available via the "normales" (since IT IS "the
statistical data for a location") and so the average temperature
should be the same in both files, but I found very important
discrepancies.
For easy, I compare the 12 average temperatures and write the
minimum and maximum (with their respective months).
Also, the coordinates didn't ever match, not even with the 3 EPW
files, ¿why all files are related to stations that don't appear as
belonging to the "national meteorological service"? I compared with
the closest "normales", which still should have similar average
temperatures.
For the Meteonorm Files:
CHIHUAHUA - Meteonorm
Location: {N 28° 42'} {W 105° 57'} 1360m above sea level
Average Temperature - Minimum: 10.4ºC December
Average Temperature - Maximum: 28.3ºC June
CHIHUAHUA - "Normal Meteorológica"
Location: {N 28° 39'00''} {W 106° 05'00''} 1430m above sea level
Average Temperature - Minimum: 9.8ºC January
Average Temperature - Maximum: 26.6ºC June
______
CUERNAVACA - Meteonorm
Location: {N 18° 54'} {W 99° 15'} 1560m above sea level
Average Temperature - Minimum: 21.2ºC January
Average Temperature - Maximum: 26.9ºC May
CUERNAVACA - "Normal Meteorológica"
Location: {N 18° 40'36''} {W 99° 05'06''} 1300m above sea level
Average Temperature - Minimum: 18.6ºC January
Average Temperature - Maximum: 23.5ºC May
______
MONTERREY - Meteonorm
Location: {N 25° 52'} {W 100° 11'} 512m above sea level
Average Temperature - Minimum: 14.4ºC January
Average Temperature - Maximum: 28.2ºC July
MONTERREY - "Normal Meteorológica"
Location: {N 25° 40'57''} {W 100° 16'01''} 495m above sea level
Average Temperature - Minimum: 14.4ºC January
Average Temperature - Maximum: 28.2ºC July and August
______
TORREÓN - Meteonorm
Location: {N 25° 31'} {W 103° 26'} 1124m above sea level
Average Temperature - Minimum: 15.1ºC December
Average Temperature - Maximum: 29.4ºC June
TORREÓN - "Normal Meteorológica"
Location: {N 25° 31'11''} {W 103° 24'57''} 1123m above sea level
Average Temperature - Minimum: 14.4ºC January
Average Temperature - Maximum: 27.9ºC June
_ _ _ _ _ _ _
For the 3 EPW files:
ACAPULCO - EPW
Location: {N 16° 46'} {W 99° 45'} 5m above sea level
Average Temperature - Minimum: 26.2ºC January
Average Temperature - Maximum: 28.4ºC July
ACAPULCO - "Normal Meteorológica"
Location: {N 16° 51'59''} {W 99° 54'20''} 20m above sea level
Average Temperature - Minimum: 26.8ºC January
Average Temperature - Maximum: 28.7ºC July
_______
CIUDAD DE MÉXICO - EPW
Location: {N 19° 25'} {W 99° 4'} 2234m above sea level
Average Temperature - Minimum: 13.6ºC December
Average Temperature - Maximum: 19.1ºC May
CIUDAD DE MÉXICO (Del. Venustiano Carranza) - "Normal Meteorológica"
Location: {N 18° 40'36''} {W 99° 05'06''} 1300m above sea level
Average Temperature - Minimum: 15.0ºC January
Average Temperature - Maximum: 21.1ºC May
_______
VERACRUZ - EPW
Location: {N 19° 12'} {W 96° 7'} 14m above sea level
Average Temperature - Minimum: 21.1ºC January
Average Temperature - Maximum: 27.6ºC May
VERACRUZ (El Tejar) - "Normal Meteorológica"
Location: {N 19° 04'02''} {W 96° 09'30''} 10m above sea level
Average Temperature - Minimum: 20.9ºC January
Average Temperature - Maximum: 28.2ºC May
_ _ _ _ _ _ _
Also, I compare the "Normal Meteorológica" for Mexicali with EPW file
for El Centro, California and "Normal Meteorológica" for Nuevo Laredo
with EPW file for Laredo, Texas. The mexican cities and the american
cities are separated only for a few km and usually in research are
taken as if they had the same climate (so, using the american EPW
files).
EL CENTRO, CALIFORNIA - EPW
Location: {N 32° 47'} {W 115° 35'} 9m above sea level
Average Temperature - Minimum: 11.6ºC January
Average Temperature - Maximum: 35.2ºC July
MEXICALI - "Normal Meteorológica"
Location: {N 32° 39'54''} {W 115° 27'21''} 4m above sea level
Average Temperature - Minimum: 13.0ºC December
Average Temperature - Maximum: 33.9ºC July
_________
LAREDO, TEXAS - EPW
Location: {N 27° 31'} {W 99° 27'} 152m above sea level
Average Temperature - Minimum: 13.8ºC January
Average Temperature - Maximum: 30.5ºC July
MEXICALI - "Normal Meteorológica"
Location: {N 27° 29'44''} {W 99° 29'25''} 128m above sea level
Average Temperature - Minimum: 12.1ºC January
Average Temperature - Maximum: 30.9ºC August
I think there are too high diferences in the average temperatures (I
don't want to think about the extrem maximum and minimum). It doesn't
make any sense to me that
1) Very close locations have very diferent climates (if it happens,
everybody should be using locally (really locally) measured
temperatures, or all their results are completely invalid, since 1ºC
is too much for an AC or a confort measure).
2) Meteonorm isn't using the data available by the meteorological
service of Mexico. What is it using if not???
I'm starting a research for various mexican cities (hot-dry) and I'm
confused about if I can relativily trust in Meteonorm, EPW (in
american counterpart cities) and/or 'Normales' files.
Maybe (still, theoretically, should't change too much), Meteonorm and
EPW are taking old 'normales' (for 1950-1980) and not the 'new' ones
(1970-2000).
DO YOU THINK IT WOULD BE USEFUL, IF I TAKE THE TEMPERATURES
OF 'NORMALES METEOROLÓGICAS' FILES AND WITH THE HELP OF AN ALGORITHM
AND A COMPUTER, CREATE HOURLY TEMPERATURES THAT MATCH AND THEN
REPLACE THE VALUES IN METEONORM AND EPW FILES??? These new files
would have all other data, so I don't have to create one, but
could 'correct' temperatures to have a more precise file (having
faith that the national metereological service works as it should and
their data is the most locally exact).
Atte.
Daniel Solís
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