Typical meteorological year
Encyclopedia
A typical meteorological year (TMY) is a collation of selected weather
data for a specific location, generated from a data bank much longer than a year in duration. It is specially selected so that it presents the range of weather phenomena for the location in question, while still giving annual averages that are consistent with the long-term averages for the location in question.
TMY data is frequently used in building simulation
, in order to assess the expected heating and cooling costs for the design of the building. It is also used by designers of solar energy systems including solar domestic hot water systems and large scale solar thermal power plants.
The first TMY collection was based on 229 locations in the US and was collected between 1948 and 1980. The second edition of the TMY is called "TMY 2". It is based on 239 stations collecting data between 1961 and 1990. The TMY2 data include Precipitable water column
(precipitable moisture), which is important in predicting radiative cooling
. The third, and latest TMY collection was based on data for 1020 locations in the USA including Guam, Puerto Rico, and US Virgin Islands, derived from a 1976-2005 period of record where available, and a 1991-2005 period of record for all other locations.
The TMY3s are data sets of hourly values of solar radiation and meteorological elements for a 1-year period. Their intended use is for computer simulations of solar energy conversion systems and building systems to facilitate performance comparisons of different system types, configurations, and locations in the United States and its territories. Because they represent typical rather than extreme conditions, they are not suited for designing systems to meet the worst-case conditions occurring at a location. The source data are available for download from the National Renewable Energy Laboratory.
The commercial software TRNSYS
and PV*SOL support simulations using TMY data. Currently, it provides a limited set of TMY data for free with its demonstration version. TMY data specific for your location will usually need to be paid for, however. On the other hand, an advanced, comprehensive, and free simulation package developed under funding from the US Department of Energy called EnergyPlus also reads TMY3 data files, and a large number of these are available at no cost from their website.
Weather
Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate...
data for a specific location, generated from a data bank much longer than a year in duration. It is specially selected so that it presents the range of weather phenomena for the location in question, while still giving annual averages that are consistent with the long-term averages for the location in question.
TMY data is frequently used in building simulation
Computer simulation
A computer simulation, a computer model, or a computational model is a computer program, or network of computers, that attempts to simulate an abstract model of a particular system...
, in order to assess the expected heating and cooling costs for the design of the building. It is also used by designers of solar energy systems including solar domestic hot water systems and large scale solar thermal power plants.
The first TMY collection was based on 229 locations in the US and was collected between 1948 and 1980. The second edition of the TMY is called "TMY 2". It is based on 239 stations collecting data between 1961 and 1990. The TMY2 data include Precipitable water column
Precipitable water column
Precipitable water is the depth of the amount of water in a column of the atmosphere if all the water in that column were precipitated as rain. As a depth, the precipitable water is measured in millimeters or inches.- Measurement :...
(precipitable moisture), which is important in predicting radiative cooling
Radiative cooling
Radiative cooling is the process by which a body loses heat by thermal radiation.- Earth's energy budget :In the case of the earth-atmosphere system it refers to the process by which long-wave radiation is emitted to balance the absorption of short-wave energy from the sun.The exact process by...
. The third, and latest TMY collection was based on data for 1020 locations in the USA including Guam, Puerto Rico, and US Virgin Islands, derived from a 1976-2005 period of record where available, and a 1991-2005 period of record for all other locations.
The TMY3s are data sets of hourly values of solar radiation and meteorological elements for a 1-year period. Their intended use is for computer simulations of solar energy conversion systems and building systems to facilitate performance comparisons of different system types, configurations, and locations in the United States and its territories. Because they represent typical rather than extreme conditions, they are not suited for designing systems to meet the worst-case conditions occurring at a location. The source data are available for download from the National Renewable Energy Laboratory.
The commercial software TRNSYS
TRNSYS
TRNSYS is a simulation program primarily used in the fields of renewable energy engineering and building simulation for passive as well as active solar design. TRNSYS is a commercial software package developed at the University of Wisconsin...
and PV*SOL support simulations using TMY data. Currently, it provides a limited set of TMY data for free with its demonstration version. TMY data specific for your location will usually need to be paid for, however. On the other hand, an advanced, comprehensive, and free simulation package developed under funding from the US Department of Energy called EnergyPlus also reads TMY3 data files, and a large number of these are available at no cost from their website.