Climate Analysis Workshop for weather files

Understanding Weather Files and Visualizing Data
Using Computerized Tools
Climate Analysis
RESULTS
LOADS
GEOMETRY
Harvard Graduate School of Design
Diego Ibarra, M.Arch, MDesS, Doctoral Student. Sustainable Design.
Digital Workshops Series

‰ Weather Files (EPW, WEA, etc)
‰ Overview of the Weather Tool
‰ Overview of Climate Consultant 4
‰ Demo: Visualization of EPW’s using
Weather Tool
‰ Demo: Editing EPW’s using Excel
Agenda
Diego Ibarra

Diego Ibarra
Context: All Environmental Design starts with a
comprehensive Climate Analysis.
1
2
3
4
Orientations Daylight CFD
Solar rays Energy use LCA

Sustainable Design…
It all starts by analyzing the local
environmental conditions….
Diego Ibarra

Different GUIs for visualizing
Weather Data
OVERVIEW
Weather Files
(i.e. Energy Plus Weather Files
EPW)
Graphical User Interfaces
Other..
Weather Data
(EPW)

‰ A TMY is a data set of hourly values of solar radiation and meteorological
elements for a 1-year period.
‰ It consists of months selected from individual years and concatenated to form
a complete year. Because of the selection criteria, TMYs are not appropriate
for simulations of wind energy conversion systems.
‰ A TMY provides a standard for hourly data for solar radiation and other
meteorological elements that permit performance comparisons of system
types and configurations for one or more locations.
‰ A TMY in not necessarily a good indicator of conditions over the next year, or
even the next 5 years. Rather, it represents conditions judged to be typical
over a long period of time, such as 30 years. Because they represent typical
rather than extreme conditions, they are not suited for designing systems and
their components to meet the worst-case conditions occurring at a location.
(User's Manual for TMY2s)
Fundamentals: Typical Meteorological Year -
A Description
Diego Ibarra

‰ TMY data sets derived from the 1953 - 1975 National Climatic
Data Center (NCDC), for 26 stations.
‰ TMY2 data sets derived from the 1961-1990 National Solar
Radiation Data Base (NSRDB), for 239 stations.
‰ TMY3 data sets derived from the 1961-1990 and 1991-2005
National Solar Radiation Data Base (NSRDB), for 1020
stations.
NOTE: TMY, TMY2 and TMY3 data sets cannot be used interchangeably because of differences in time (solar
versus local), formats, elements, and units. Unless they are revised, programs designed for TMY data will not
work with TMY2 data.
All illuminance and luminance values for all TMY3 stations from January 2 to 31 should be multiplied by 100
to obtain the correct units of Lux and Candela per square meter. NREL will be posting a corrected data set in
the near future (older TMY3s).
Weather Data Sets
Diego Ibarra

‰ WEA: Weather Data File
‰ EPW: Energy Plus Weather Data files
‰ IWEC (Data set: new International
Weather for Energy Calculations format
from ASHRAE)
Weather Files
Diego Ibarra

International Weather for Energy Calculations (IWEC)
The IWEC are the result of ASHRAE Research Project 1015 by Numerical Logics and
Bodycote Materials Testing Canada for ASHRAE Technical Committee 4.2
Weather Information. The IWEC data files are 'typical' weather files suitable for
use with building energy simulation programs for 227 locations outside the USA
and Canada. All 227 locations in the IWEC data set are available for download in
EnergyPlus weather format.
The files are derived from up to 18 years of DATSAV3 hourly weather data originally
archived at the U. S. National Climatic Data Center. The weather data is
supplemented by solar radiation estimated on an hourly basis from earth-sun
geometry and hourly weather elements, particularly cloud amount information.
The IWEC CD-ROM is available from ASHRAE. The reference for the IWEC is:
ASHRAE. 2001. International Weather for Energy Calculations (IWEC Weather Files)
Users Manual and CD-ROM, Atlanta: ASHRAE
Weather Files
Diego Ibarra

‰ Global Irradiation is the amount of energy striking a horizontal surface
during the hour.
‰ Direct Beam Irradiation gives the irradiation striking a plate perpendicular
to the sun's rays but does not include diffuse radiation.
‰ Dry Bulb Temperature and Wind Speed are averaged over the hour.
‰ The Wet Bulb Temperature is the temperature shown by a thermometer
bulb surrounded by a damp wick. The WBT varies from the dry bulb
temperature according to the amount of evaporation and thus the humidity.
‰ Wind Direction shows the compass points from which the wind is coming.
Usually measured at 10mts high at an unobstructed location (airports).
‰ Cloud Cover is a visual estimate of the proportion of cloud covering the sky.
In this case it is in eights so 0 is no cloud and 8 is full cloud cover.
Weather Files
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‰ Hourly temperatures
‰ Solar radiation (global and direct)
‰ Humidity
‰ Wind (direction and speed)
‰ Cloud cover
Weather Files summary…
Diego Ibarra

‰ The Weather Tool uses its own proprietary .WEA file
format, also used by all Square One products.
‰ File sizes were once an issue…. some ASCII weather files
are “larger”, such as the TMY2 format for example,
weighing in at over 1.2Meg. The WEA file comes in at
139K, stores roughly the same data and compresses
down to less than 55K.
‰ It DOES NOT store the same number of data validation
flags as EPWs, however this is not necessary for the uses
to which it is put in a weather visualization tool. Be sure
in the future to run energy simulations with EPW files.
WeatherTool File Format: .WEA
Diego Ibarra

‰ Weather data for more than 2100 locations are now
available in EnergyPlus weather format — 1042
locations in the USA, 71 locations in Canada, and
more than 1000 locations in 100 other countries
throughout the world. (Compiled from TMY, TMY2,
TMY3, and other international data sets).
EPW: U.S. Department of Energy
Diego Ibarra

Downloading EPW’s
Diego Ibarra

Each file is named using the ISO standard three-letter country abbreviation (i.e. CUB for
Cuba), followed by the location name, World Meteorological Organization designation
(WMO) and the source format (CTZ2, CWEC, CityUHK, CSWD, CTYW, ETMY, IGDG, IMGW,
IMS, INETI, ISHRAE, ITMY, IWEC, KISR, NIWA, RMY, SWEC, SWERA, or TMY3). Thus,
CUB_Havana.782240_IWEC.epw — is the EnergyPlus weather file (EPW) from the
ASHRAE International Weather for Energy Calculations (IWEC) data for Havana, Cuba,
WMO 782240.
There are three files associated with each location: EnergyPlus weather files (EPW), a
summary report on the data (STAT), and a compressed file (ZIP) which contains the EPW,
STAT, and DDY (design conditions) files for the location. Note: all IWEC files only have
STAT and ZIP files.
Viewing Instructions
You can view the individual EPW and STAT files by clicking on one of the buttons above.
Download Instructions
For a specific location, you can download either Individual weather data files (EPW
format) or a data summary report (STAT format). File sizes range from 0.9 - 1.4 MB.
Or a ZIP file containing both weather data and summary report, EPW, and STAT formats.
Files sizes range from 190 - 250 KB.
EPW: U.S. Department of Energy
Diego Ibarra

‰ The Weather Tool is a
visualization and analysis
program for hourly climate
data. It recognizes a wide
range of international
weather file formats.
Weather Tool (Originally Square One bought by Autodesk…)
Graphical User Interface
Diego Ibarra

‰ Very user friendly Graphical User Interface. If you are
using ECOTECT, it comes with the suite. Maintains a
design expression of a report or presentation.
‰ Flashy visualizations: loved by architects and great
impact on clients.
‰ Easier to identify SOME patterns and subtle details that
characterize each different climate. (Solar)
‰ Thresholds are less customizable and less detailed.
‰ No available detailed technical information about the
passive strategies criteria (black box).
Weather Tool- Benefits
Diego Ibarra

‰ No available detailed technical information about
the passive strategies criteria (black box).
‰ USE MAINLY TO DERIVE GENERAL CLIMATIC
CONDITIONS or TO CARRY OUT CLIMATE
COMPARISONS. (Relative Differences)
‰ For detailed quantitative analysis the use of
Climate Consultant is suggested.
Weather Tool- Benefits
Diego Ibarra

Diego Ibarra
Stereographic Chart
Shifting the curve to the left
1
2
3
4
Boston: June

Diego Ibarra
Stereographic Chart
1
2
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4
Boston: October

Diego Ibarra
Stereographic Chart
1
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4
Boston: December

Diego Ibarra
Stereographic Chart
1
2
3
4
Boston: March

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Stereographic Chart
1
2
3
4
Boston: All year

Diego Ibarra
Stereographic Chart
1
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4
Boston: All year plan view

Diego Ibarra
Stereographic Chart
1
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4
Boston: view in Weather Tool

Diego Ibarra
Stereographic Chart
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4
How to read the chart…

Diego Ibarra
Stereographic Chart: azimuth angles
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3
4
130°

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Stereographic Chart: Altitude Lines
1
2 129°
Degrees°

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Stereographic Chart: Date Lines
1
2 July
Months
Dec

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Stereographic Chart: Hour Lines
1
9:00am
Hours

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Stereographic Chart
1
2
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4
Or just read….

Diego Ibarra
Psychrometric Chart
1
2
3
4
How to read the chart…

Diego Ibarra
Psychrometric Chart: temperature axis
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4
Temperature (C° - F°)

Diego Ibarra
Psychrometric Chart: temperature lines
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4
Temperature (C° - F°)

Diego Ibarra
Psychrometric Chart: absolute humidity axis
1
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4
Absolute Humidity
W
(g/kga)

Diego Ibarra
Psychrometric Chart. Absolute humidity lines
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4
Temperature
W
(g/kga)

Diego Ibarra
Psychrometric Chart: dew point line
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Dew point

Diego Ibarra
1
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Dew point
(condensation)
30 C°
35
g/kga

Diego Ibarra
1
2
3
4
Dew point
(condensation)
20 C°
15
g/kga

Diego Ibarra
Psychrometric Chart: relative humidity idea
30 C°
50 %
75 %
25 %
100 %
0 %

Diego Ibarra
Psychrometric Chart: Relative Humidity lines
1
2
Relative Humidity Lines
Connecting the lines at each
specific temperature
50 %
75 %
25 %

Diego Ibarra
Psychrometric Chart: WBT (wet bulb temp.)
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2
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4
More air mixture
information hidden
in the graph…

Diego Ibarra
Psychrometric Chart: Enthalpy
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4
More air mixture
information hidden
in the graph…
Joules/Kg of dry air
(20.000-110.000)

Diego Ibarra
Psychrometric Chart: Specific Volume
1
2
3
4
More air mixture
information hidden
in the graph…
m3/Kg of dry air

Diego Ibarra
Psychrometric Chart
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Comfort Zone

Diego Ibarra
Weather Tool
Weather file directory

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Weather Tool
Data Categories

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Weather Tool
Data visualization

Diego Ibarra
Analysis Techniques: Climate Comparison
ABU DHABI:
Average Dry Bulb Temperature
Max: 43° C
BOSTON:
Average Dry Bulb Temperature
Max: 20 ° C

Diego Ibarra
Analysis Techniques: Climate Comparison
ABU DHABI :
Direct Solar Radiation
Max. aprox: 900 W/m2
BOSTON:
Direct Solar Radiation
Max. aprox: 500 W/m2

Diego Ibarra
Sun position 22 October 8:30pm -117.3º, 26.7º
Sun position 19 November 12:00pm -177.8º, 46.3º
Sun position 22 October 4:30pm -103.8º, 21.5º
South : 956 kWh/m2/a
East : 778 kWh/m2/a
-132 Degrees:
1,083 kWh/m2/a
North : 343 kWh/m2/a
Analysis Techniques: Absolute values

‰ Developed by the Department of
Architecture and Urban Design.
University of California, Los
Angeles.
‰ Graphically displays climate data
in either metric or imperial units
in dozens of ways useful to
architects.
Climate Consultant 4
Graphical User Interface
Diego Ibarra

‰ Easier to identify unique patterns and subtle details that
characterize each different climate.
‰ Thresholds and comfort zones are more flexible.
‰ In contrast to The Weather Tool, detailed technical
information about the passive strategies criteria is
documented and freely available.
Climate Consultant 4 - Benefits
Diego Ibarra

‰ The “Wind Wheel” graphics shows velocity and
direction correlated with temperature and
humidity, and can be animated hourly or daily or
monthly.
‰ The psychrometric analysis recommends the most
appropriate passive design strategies as outlined
in Givoni’s Man Climate and Architecture.
‰ Climate Consultant is written in Java and runs on
both Windows and Mac OS X computers.
Diego Ibarra

Diego Ibarra

‰ It now calculates a set of the top 20 Design Guidelines
based on your unique climate and the passive design
strategies you selected on the Psychrometric Chart.
‰ Each Guideline has a sketch illustrating how it applies. The
Guidelines and their accompanying sketches were based in
part on Watson and Labs Climatic Building Design, and on
Loftness,.et.al, Regional Guidelines for Building Passive
Energy Conserving Homes.
Diego Ibarra
Top 20 Passive Design Guidelines

GSD 6413 – ZED WORKSHOP – RESEARCH NAME
18 SEP 2009
* source: Energy center of Wisconsin
Diego Ibarra
Selecting Passive Strategies
must take into account the building typology/use

‰ Vista users sometimes have installation problems. In the
current version, the C:Program Files has a stringent
security mechanism that has resulted in many complaints.
Users cannot explicitly create files in this directory hierarchy.
Vista 7 may allow users to lower this level of security. Here
is a workaround. When you install the program, explicitly
change the target directory to C:CC4 in order to bypass the
C:Program Files security restriction then the installation
should finish without error.
Windows VISTA installation issues
Diego Ibarra

‰ For more information download the technical paper for Climate
Consultant:
“Climate Consultant 3.0: A Tool for Visualizing Building Energy
Implications of Climates” Murray Milne, Robin Liggett, and Rashed
Al-Shaali, Proceedings of the American Solar Energy Association
Conference, Cleveland, Ohio, July, 2007.
http://www2.aud.ucla.edu/energy-design-tools/papers.html
‰ Developers: Professor Murray Milne
Department of Architecture and Urban Design
University of California, Los Angeles
Los Angeles, California 90095-1467
milne@ucla.edu
Technical Paper – Climate Consultant
Diego Ibarra

Demo…
Diego Ibarra
‰ The Weather Tool
‰ Climate Consultant 4
‰ Importing EPW’s
‰ Editing EPW’s in Excel

Questions…
dibarra@gsd.harvard.edu
Diego Ibarra

Climate Analysis Workshop for weather files

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