Hourly Weather Data Report Files

When using the Weather Data Analysis tool (aka Weather Converter) to create a new .epw or .csv file, 3 report files are generated:

 

 

The Weather Converter checks the ASHRAE design condition files to see if a location with a corresponding WMO (World Meteorological Organization) Id can be found, and if so, the relevant ASHRAE design data is included in the reports.

Audit / Log File (.audit)

As an example, the initial portion of an audit file is shown (illustrating the error reporting) under the expanding header below.

 

-Input File Type=EPW, with FileName=C:\Users\AndyT1\AppData\Local\Temp\WeatherDataTempFile 2.epw

-Out of Range Data items will be corrected.

- Start Date/End Date for Weather Source

Start Date=Jan 1; End Date=Dec 31

- Actual Data Years for Monthly Data**

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

2002 2002 2002 2002 2002 2002 2002 2002 2002 2002 2002 2002

- ** Not all weather data sources represent contiguous years.

- ** Monthly data values may come from different years.

- Days per Month for Monthly Data**

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

31 28 31 30 31 30 31 31 30 31 30 31

- ** Number of days per month seems okay.

- Data Sources should be checked for relevancy to these statistics.

Average Delta DB Change= 0.86°C ; Std Dev= 0.87°C

Average Delta DP Change= 0.62°C ; Std Dev= 0.73°C

Average Delta Relative Humidity Change= 3.86% ; Std Dev= 3.95%

Average Delta Wind Speed Change= 0.96m/s ; Std Dev= 0.90m/s

Hourly Dry Bulb temperature change trigger = minimum of 12.97°C and 10.°C

12.97°C = calculated trigger based on mean change in dry-bulb temperature and standard deviation shown above

10.°C = trigger set by user

Changes indicated in delta temperatures, details follow.

*****

- Delta DB/DP Range Triggered for Feb 23

- Change in DP=-10.60°C, Hour= 8

*****

- Delta DB/DP Range Triggered for May 5

- Change in DB= 11.10°C, Hour=19

-Output File Type=epw, with FileName=C:\ProgramData\DesignBuilder\Weather Data\USA_IL_CHICAGO-OHARE INTL AP_TMY3.epw

Statistical Report File (.stat)

The .stat file provides a useful summary of the weather data, including:

 

 

In the “reporting” sections of the file, each line contains tab-delimited values , allowing you to easily copy/paste the data into a spreadsheet for further analysis.

 

Statistics for USA_IL_CHICAGO-OHARE INTL AP_TMY3

Location -- Chicago-OHare Intl AP IL USA

{N 41° 58'} {W 87° 55'} {GMT -6.0 Hours}

Elevation -- 201m above sea level

Standard Pressure at Elevation -- 98934Pa

Data Source -- TMY3

WMO Station 725300

- Using Design Conditions from "Climate Design Data 2005 ASHRAE Handbook"

- If the design condition source is ASHRAE, the design conditions are carefully generated

- from a period of record (typically 30 years) to be representative of that location and

- be suitable for use in heating/cooling load calculations. If the source is not ASHRAE,

- please consult the referenced source for the reasoning behind the data.

Design Stat Coldest month HDB 99.6% HDB 99% Hm-DP 99.6% Hm-HR 99.6% Hm-MCDB 99.6% Hm-DP 99% Hm-HR 99% Hm-MCDB 99% CMn-WS .4% CMn-MCDB .4% CMn-WS 1% CMn-MCDB 1% MCWS-99.6%DB PCWD-99.6%DB

Units {} {°C} {°C} {°C} {} {°C} {°C} {} {°C} {m/s} {°C} {m/s} {°C} {m/s} {deg}

Heating 1 -20.6 -17.3 -26.5 0.3 -19.7 -23.2 0.5 -16.8 12.8 -4.7 11.8 -4.1 4.9 270

Design Stat Hottest month HMn-DB Range CDB .4% CMCWB .4% CDB 1% CMCWB 1% CDB 2% CMCWB 2% ECWB .4% EMCDB .4% ECWB 1% EMCDB 1% ECWB 2% EMCDB 2% MCWS-.4%DB PCWD-.4%DB D DP .4% D HR .4% D MCDB .4% D DP 1% D HR 1% D MCDB 1% D DP 2% D HR 2% D MCDB 2% Ent .4% MCDB .4% Ent 1% MCDB 1% Ent 2% MCDB 2%

Units {} {°C} {°C} {°C} {°C} {°C} {°C} {°C} {°C} {°C} {°C} {°C} {°C} {°C} {m/s} {deg} {°C} {} {°C} {°C} {} {°C} {°C} {} {°C} {kJ/kg} {°C} {kJ/kg} {°C} {kJ/kg} {°C}

Cooling 7 10.7 33.2 23.8 31.5 23 29.9 22.1 25.5 31.2 24.5 29.6 23.5 28.1 5.3 230 23.8 19 29 22.8 17.9 27.9 21.9 16.9 26.7 79 31.2 74.9 29.6 70.8 28.1

Design Stat X WS 1% X WS 2.5% X WS 5% X Max WB X Max DB X Min DB Sdev Max DB Sdev Min DB

Units {m/s} {m/s} {m/s} {°C} {°C} {°C} {°C} {°C}

Extremes 11.2 9.9 8.7 28.5 35.7 -24.2 1.7 4.2

If the source hourly weather file WMO station Id is not found in the ASHRAE design conditions database then the design statistics must be calculated from the source hourly data.

 

Statistics for UK_ LONDON HEATHROW AIRPORT _

Location -- London Heathrow Airport - UK

{N 51° 28'} {W 0° 26'} {GMT +0.0 Hours}

Elevation -- 25m above sea level

Standard Pressure at Elevation -- 101025Pa

Data Source -- CIBSE/Met Office

WMO Station *unknown*

- Using Design Conditions calculated from this weather file.

- The following design temperature statistics are calculated based on THIS weather file ONLY

- and may not be representative of a long-term period of record normally used for

- design temperatures. Also, note that dew point temperatures are listed where

- wet-bulb temperatures are normally presented.

Design Stat Coldest Month HDB 99.6% HDB 99%

Units {} {C} {C}

Heating 11 -2.7 -1.4

Design Stat Hottest Month CDB .4% CDB 1% CDB 2% CDP .4% CDP 1% CDP 2%

Units {} {C} {C} {C} {C} {C} {C}

Cooling 7 32.1 30.7 29.3 19.4 18.7 17.9

Design Stat Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Units {m/s} {m/s} {m/s} {m/s} {m/s} {m/s} {m/s} {m/s} {m/s} {m/s} {m/s} {m/s}

Max WS 8.7 8.2 9.8 10.3 7.7 7.2 8.2 9.8 7.7 11.8 12.3 12.9

These are followed by groupings of Monthly temperature data.

 

- Monthly Statistics for Dry Bulb temperatures °C

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Maximum 12.2 14.4 21.1 31.1 30.6 33.3 35.0 31.7 31.7 26.1 21.7 11.1

Day:Hour 21:15 23:10 27:15 15:15 5:13 8:13 19:15 3:14 27:16 21:14 2:13 7:15

Minimum -22.8 -21.7 -7.8 -3.9 1.7 6.7 11.7 11.7 6.7 -0.6 -16.1 -18.3

Day:Hour 7:07 6:05 18:03 4:24 9:05 25:04 3:04 7:01 25:06 24:03 26:07 20:07

Daily Avg -4.6 -2.5 3.8 10.0 15.3 21.1 24.1 21.8 18.1 11.0 4.7 -3.7

- Maximum Dry Bulb temperature of 35.0°C on Jul 19

- Minimum Dry Bulb temperature of -22.8°C on Jan 7

- Average Hourly Statistics for Dry Bulb temperatures °C

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

0:01- 1:00 -6.3 -3.7 2.0 7.8 10.7 17.6 20.7 18.6 14.9 8.5 3.7 -4.9

1:01- 2:00 -6.2 -3.9 1.8 7.6 10.3 17.3 20.3 18.3 14.5 8.2 3.5 -4.8

2:01- 3:00 -6.1 -4.1 1.8 7.6 10.2 17.2 19.9 18.2 14.1 8.0 3.4 -4.9

3:01- 4:00 -6.3 -4.5 1.2 7.2 10.1 16.9 19.7 17.7 13.9 7.8 3.4 -5.2

4:01- 5:00 -6.5 -4.9 1.1 7.0 9.9 16.7 19.5 17.7 13.7 7.8 3.1 -5.3

5:01- 6:00 -6.8 -5.1 0.9 7.0 11.2 17.6 20.7 18.0 13.6 7.5 2.8 -5.6

6:01- 7:00 -6.8 -5.3 1.4 8.1 13.6 19.6 22.4 20.1 15.5 8.1 2.8 -5.7

7:01- 8:00 -6.6 -4.6 2.8 9.3 15.5 21.3 23.7 21.7 17.6 9.9 3.5 -5.4

8:01- 9:00 -5.6 -3.3 4.0 10.2 17.3 22.5 25.0 23.3 19.4 11.8 4.3 -4.5

9:01-10:00 -4.4 -2.1 5.1 10.9 18.7 23.6 26.1 24.6 20.5 13.2 5.5 -3.2

10:01-11:00 -3.5 -1.0 5.9 11.8 19.8 24.4 27.0 25.2 21.4 14.3 6.3 -2.1

11:01-12:00 -2.8 -0.2 6.8 12.3 20.6 24.8 27.8 25.4 22.2 14.9 7.0 -1.5

12:01-13:00 -2.0 0.3 7.2 12.8 21.1 25.2 28.4 25.9 22.8 15.2 7.2 -0.9

13:01-14:00 -1.7 0.4 7.3 13.1 20.9 25.5 28.6 25.7 23.2 15.4 7.4 -0.7

14:01-15:00 -1.6 0.5 7.2 13.0 20.6 25.4 28.5 25.4 22.9 15.3 7.3 -0.7

15:01-16:00 -1.9 0.3 6.8 12.8 20.0 25.1 28.0 25.2 22.5 14.6 6.7 -1.5

16:01-17:00 -2.9 -0.5 6.1 12.4 19.5 24.8 27.3 24.5 21.6 13.3 5.9 -2.5

17:01-18:00 -3.8 -1.4 5.0 11.5 18.1 24.0 26.5 23.8 20.0 11.8 5.3 -3.3

18:01-19:00 -4.5 -2.3 3.9 10.6 16.1 22.3 25.4 22.4 18.6 11.0 4.6 -3.7

19:01-20:00 -4.5 -2.6 3.3 9.9 14.5 20.7 24.0 21.5 17.8 10.4 4.2 -4.0

20:01-21:00 -4.7 -2.9 2.9 9.5 13.3 19.4 23.2 20.6 16.9 9.8 4.2 -4.2

21:01-22:00 -5.0 -2.9 2.6 9.2 12.5 18.8 22.6 20.3 16.5 9.3 4.1 -4.4

22:01-23:00 -5.2 -3.1 2.4 8.9 11.8 18.1 22.0 19.6 15.9 8.7 3.8 -4.5

23:01-24:00 -5.9 -3.4 2.1 8.4 11.4 17.9 21.6 19.0 15.3 8.5 3.7 -5.0

Max Hour 15 15 14 14 13 14 14 13 14 14 14 15

Min Hour 6 7 6 5 5 5 5 5 6 6 7 7

- Monthly Statistics for Extreme temperatures °C

#Days Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Max >= 32 3 8

Max <= 0 14 14 1 4 15

Min <= 0 29 22 20 5 3 13 29

Min <=-18 5 3 2

- Monthly Statistics for Dew Point temperatures °C

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Maximum 6.1 11.1 13.9 18.3 20.6 23.3 25.0 25.6 20.0 13.9 17.2 6.7

Day:Hour 21:17 23:15 28:03 18:09 30:09 8:09 19:17 4:21 6:17 2:19 3:19 1:08

Minimum -28.3 -27.8 -13.3 -8.3 -6.1 -1.1 7.8 7.2 -0.6 -2.8 -20.6 -21.7

Day:Hour 27:06 7:07 5:19 4:09 6:20 25:03 3:11 17:04 30:15 14:19 26:07 30:01

Daily Avg -9.4 -8.2 -1.5 4.0 7.2 13.0 18.7 16.6 12.9 5.0 0.4 -7.6

- Maximum Dew Point temperature of 25.6°C on Aug 4

- Minimum Dew Point temperature of -28.3°C on Jan 27

- Monthly Statistics for Relative Humidity %

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Maximum 100 92 100 100 100 100 100 100 100 93 100 100

Day:Hour 2:18 18:08 13:10 1:16 1:24 8:22 1:17 19:24 9:04 1:24 7:01 1:02

Minimum 35 31 30 24 17 25 36 37 28 32 39 47

Day:Hour 27:14 16:16 21:14 30:13 4:17 3:14 7:12 30:14 27:16 13:13 26:13 11:13

Daily Avg 71 66 71 69 63 62 74 74 75 69 75 75

- Average Hourly Relative Humidity %

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

0:01- 1:00 78 69 76 77 76 70 87 85 90 77 77 79

1:01- 2:00 78 69 76 78 77 72 89 87 91 79 77 79

2:01- 3:00 77 70 76 78 79 72 90 87 92 79 79 80

3:01- 4:00 77 70 77 79 80 74 91 87 92 80 79 81

4:01- 5:00 78 71 78 80 81 76 91 88 92 80 81 81

5:01- 6:00 77 70 81 79 81 76 88 86 92 80 82 82

6:01- 7:00 76 71 80 75 72 72 82 80 86 81 83 82

7:01- 8:00 74 72 76 71 64 68 77 75 76 76 80 81

8:01- 9:00 71 71 72 67 58 65 72 70 69 68 78 78

9:01-10:00 67 70 68 64 54 61 67 64 64 62 73 74

10:01-11:00 64 65 67 61 50 57 63 62 61 57 70 69

11:01-12:00 63 61 63 61 48 55 60 61 58 54 68 68

12:01-13:00 61 60 61 59 47 54 58 59 55 54 66 65

13:01-14:00 60 58 60 59 46 53 57 60 55 53 66 65

14:01-15:00 60 58 60 60 47 52 56 60 55 53 66 64

15:01-16:00 61 58 61 61 48 51 58 61 56 54 68 66

16:01-17:00 65 59 62 62 49 50 61 63 59 59 72 70

17:01-18:00 68 61 66 63 53 51 63 66 65 64 75 74

18:01-19:00 72 65 70 66 57 54 66 71 71 68 76 76

19:01-20:00 72 67 73 70 62 57 71 76 75 70 78 77

20:01-21:00 73 69 73 72 66 60 76 80 80 72 78 76

21:01-22:00 75 70 74 73 71 63 78 81 81 73 75 77

22:01-23:00 75 70 75 74 74 66 82 83 85 76 77 77

23:01-24:00 77 69 76 76 75 68 84 84 87 77 77 77

Max Hour 5 8 6 5 5 6 5 5 5 7 7 6

Min Hour 14 16 14 13 14 17 15 13 14 15 15 15

- Monthly Indicators for Precipitation/Moisture (kPa)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

0.3 0.4 0.6 0.9 1.1 1.7 2.2 2.0 1.5 0.9 0.8 0.4

- Monthly Statistics for Wind Chill/Heat Index temperatures °C **

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Minimum WC -43 -30 -23 -11 -2 3 5 -5 -32 -33

Day:Hour 27:08 5:12 5:05 1:01 8:06 25:04 25:04 16:06 25:23 20:19

Average WC -13 -11 -5 -1 5 6 8 1 -8 -11

Avg Del WC 8 8 8 6 3 1 0 5 8 7

# Hours WC 716 634 635 386 124 7 23 294 460 703

Maximum HI 31 31 39 40 38 30

Day:Hour 18:13 30:16 8:13 19:17 4:15 6:11

Average HI 29 29 30 33 31 28

Avg Del HI 0 1 1 3 2 0

# Hours HI 15 9 76 201 95 16

- **WindChill/HeatIndex Temps -- statistics...only those different from Air Temps

- Monthly Wind Direction % {N=0 or 360,E=90,S=180,W=270}

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

North 11 10 7 14 15 14 15 12 15 9 11 10

NorthEast 1 4 16 12 23 13 12 14 6 4 11 1

East 2 0 8 10 14 6 5 5 4 2 1 0

SouthEast 5 0 7 5 6 9 7 6 7 2 8 4

South 17 15 13 18 12 19 18 12 15 25 23 15

SouthWest 17 19 15 17 3 19 18 19 13 22 8 19

West 23 32 21 11 11 11 16 19 24 19 23 23

NorthWest 24 19 14 13 15 7 10 13 16 16 15 28

- Monthly Statistics for Wind Speed m/s

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Maximum 12.9 12.4 15.4 12.9 12.9 11.3 11.8 9.8 8.8 10.3 12.4 12.9

Day:Hour 21:19 24:17 4:23 24:18 13:13 20:17 4:13 6:11 17:15 16:01 20:12 20:21

Minimum 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Day:Hour 1:17 7:06 4:09 1:08 3:20 1:18 7:04 1:23 5:05 1:14 8:02 2:24

Daily Avg 4.9 5.1 5.5 4.8 3.7 4.9 4.2 3.8 3.4 4.8 5.3 4.3

- Maximum Wind Speed of 15.4 m/s on Mar 4

- Minimum Wind Speed of 0.0 m/s on Jan 1

- Monthly Statistics for Liquid Precipitation mm

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Total 0 0 0 0 0 0 0 0 0 0 0 0

- Monthly Statistics for Albedo

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Average 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100

- Monthly Statistics for Solar Radiation (Direct Normal, Diffuse, Global Horizontal) Wh/m²

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Direct Avg 2335 2737 3146 3668 5014 5205 4829 4194 4004 3268 1880 2211

Direct Max 6874 7472 8929 8384 10148 9706 8814 9321 7925 7690 5672 6563

Day 27 15 15 23 3 24 5 18 4 27 14 5

Diffuse Avg 956 1330 1740 2057 2539 2690 2800 2422 1861 1394 1089 799

Global Avg 1764 2493 3440 4394 5976 6294 6177 5161 4193 2941 1819 1504

- Maximum Direct Normal Solar of 10148 Wh/m² on May 3

- Average Hourly Statistics for Direct Normal Solar Radiation Wh/m²

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

0:01- 1:00 0 0 0 0 0 0 0 0 0 0 0 0

1:01- 2:00 0 0 0 0 0 0 0 0 0 0 0 0

2:01- 3:00 0 0 0 0 0 0 0 0 0 0 0 0

3:01- 4:00 0 0 0 0 0 0 0 0 0 0 0 0

4:01- 5:00 0 0 0 0 6 23 5 0 0 0 0 0

5:01- 6:00 0 0 0 15 132 192 108 59 15 1 0 0

6:01- 7:00 0 3 63 196 283 325 273 227 187 74 4 0

7:01- 8:00 38 81 220 253 377 411 322 321 316 241 80 65

8:01- 9:00 182 188 284 317 432 477 387 360 411 384 211 230

9:01-10:00 268 309 335 349 477 465 412 427 442 408 230 286

10:01-11:00 304 370 384 356 475 494 425 408 440 408 277 327

11:01-12:00 317 343 362 376 475 445 466 415 389 357 285 313

12:01-13:00 333 371 381 346 492 433 503 388 412 376 266 307

13:01-14:00 341 313 363 404 470 428 439 355 396 384 263 276

14:01-15:00 291 307 292 377 412 422 430 338 366 299 164 245

15:01-16:00 206 289 237 295 363 397 381 370 331 237 87 146

16:01-17:00 55 152 176 222 327 307 342 282 223 96 12 15

17:01-18:00 0 11 51 154 224 262 245 191 75 3 0 0

18:01-19:00 0 0 0 9 70 119 89 52 3 0 0 0

19:01-20:00 0 0 0 0 0 6 3 0 0 0 0 0

20:01-21:00 0 0 0 0 0 0 0 0 0 0 0 0

21:01-22:00 0 0 0 0 0 0 0 0 0 0 0 0

22:01-23:00 0 0 0 0 0 0 0 0 0 0 0 0

23:01-24:00 0 0 0 0 0 0 0 0 0 0 0 0

Max Hour* 14 13 11* 14 13 11* 13 10* 10* 10* 12 11*

Min Hour 1 1 1 1 1 1 1 1 1 1 1 1

- Monthly Calculated "undisturbed" Ground Temperatures** °C

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

0.5 m -1.9 -3.1 -1.0 2.2 10.7 17.2 21.6 22.9 20.7 15.6 8.8 2.6

2.0 m 2.4 0.3 0.7 2.5 8.1 13.2 17.3 19.5 19.0 16.2 11.5 6.6

4.0 m 5.9 3.8 3.3 4.0 7.2 10.6 13.8 16.0 16.5 15.2 12.5 9.2

- **These ground temperatures should NOT BE USED in the GroundTemperatures object to compute building floor losses.

- The temperatures for 0.5 m depth can be used for GroundTemperatures:Surface.

- The temperatures for 4.0 m depth can be used for GroundTemperatures:Deep.

- Calculations use a standard soil diffusivity of 2.3225760E-03 {m**2/day}

- Monthly Heating/Cooling Degree Days/Hours

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

HDD base 10C 454 352 197 89 3 0 0 0 0 30 199 424

HDD base 18C 702 575 439 268 104 12 1 2 38 218 398 672

CDD base 10C 0 2 5 87 168 333 438 365 244 60 41 0

CDD base 18C 0 0 0 27 21 105 191 119 42 1 0 0

CDH base 20C 0 0 1 520 703 2077 3409 2029 845 69 7 0

CDH base 23C 0 0 0 258 302 1043 1866 869 320 10 0 0

CDH base 27C 0 0 0 71 47 285 599 155 50 0 0 0

- 1743 annual cooling degree-days (10°C baseline)

- 1748 annual heating degree-days (10°C baseline)

- 506 annual cooling degree-days (18°C baseline)

- 3430 annual heating degree-days (18°C baseline)

- Climate type "Dfa" (Köppen classification)**

- Humid continental (hot summer, cold winter, no dry season, lat. 30-60°N)

- Unbearably humid periods in summer, but passive cooling is possible

- **Note that the Köppen classification shown here is derived algorithmically from the source weather data.

- It may not be indicative of the long term climate for this location.

- Climate type "5A" (ASHRAE Standards 90.1-2004 and 90.2-2004 Climate Zone)**

- Cool - Humid, Probable Köppen classification=Dfa, Humid Continental (Warm Summer)

- **Note that the ASHRAE classification shown here is derived algorithmically from the source weather data.

- It may not be indicative of the long term climate for this location.

- Typical/Extreme Period Determination

- Summer is Jun:Aug

Extreme Summer Week (nearest maximum temperature for summer)

Extreme Hot Week Period selected: Jul 13:Jul 19, Maximum Temp= 35.00°C, Deviation=| 8.451|°C

Typical Summer Week (nearest average temperature for summer)

Typical Week Period selected: Aug 24:Aug 30, Average Temp= 22.35°C, Deviation=| 0.095|°C

- Winter is Dec:Feb

Extreme Winter Week (nearest minimum temperature for winter)

Extreme Cold Week Period selected: Jan 27:Feb 2, Minimum Temp= -22.80°C, Deviation=|12.651|°C

Typical Winter Week (nearest average temperature for winter)

Typical Week Period selected: Dec 22:Dec 28, Average Temp= -3.65°C, Deviation=| 0.123|°C

- Autumn is Sep:Nov

Typical Autumn Week (nearest average temperature for autumn)

Typical Week Period selected: Oct 27:Nov 2, Average Temp= 11.28°C, Deviation=| 0.020|°C

- Spring is Mar:May

Typical Spring Week (nearest average temperature for spring)

Typical Week Period selected: Apr 26:May 2, Average Temp= 9.69°C, Deviation=| 0.357|°C

Design Day Calculations Output (.ddy)

Using the WMO field (or determining it from the WBAN field), the Weather Converter performs table look up in the Design Condition files to see if there are recorded design conditions for the subject location. If the location is found, then design day objects are produced on the resultant design day object (ddy extension) file - ready for inclusion in an EnergyPlus input data file. If no design conditions are located, then the design day object file will still include a location object for inclusion with EnergyPlus. However, statistics using the weather file are displayed to the statistics file - these “can” be used to create your own design day definitions but you should read the warning that is issued and take care if your weather file is only a “single instance” weather data representation.

 

The location objects as well as the design condition objects are constrained by the data source. Some data sources do not have elevation information - thus, a location object from such a source will have an elevation of 0.0. Likewise, the time zone of some locations may not be available from the source data nor other data resources that the weather converter uses. A time zone will be estimated from the standard meridian of the location (determined by the longitude) but it may not be accurate. A user needs to be aware of these limitations when taking the design day files from the weather converter.

 

Note that you can always include a “def” file with this data to assure accuracy regardless of input format limitations.

 

An excerpt of a design day output are shown under the expanding header below. Actual design day objects have been deleted for brevity. Note that with the 2009 ASHRAE HOF climate conditions, a DaylightSavingPeriod object may be included.

 

! The following Location and Design Day data are produced as possible from the indicated data source.

! Wind Speeds follow the indicated design conditions rather than traditional values (6.7 m/s heating, 3.35 m/s cooling)

! No special attempts at re-creating or determining missing data parts (e.g. Wind speed or direction)

! are done. Therefore, you should look at the data and fill in any incorrect values as you desire.

 

Site:Location,

 Chicago-OHare Intl AP_IL_USA Design_Conditions, !- Location Name

     41.98,      !- Latitude {N+ S-}

    -87.92,    !- Longitude {W- E+}

    -6.00,        !- Time Zone Relative to GMT {GMT+/-}

    201.00;   !- Elevation {m}

 

! WMO=725300 Time Zone=NAC: (GMT-06:00) Central Time (US & Canada)

! Data Source=ASHRAE 2005 Annual Design Conditions

RunPeriodControl:DaylightSavingTime,

 1st Sunday in April,    !- StartDate

 Last Sunday in October; !- EndDate

 

! Using Design Conditions from "Climate Design Data 2005 ASHRAE Handbook"

! Chicago-OHare Intl AP_IL_USA Extreme Annual Wind Speeds, 1%=11.2m/s, 2.5%=9.9m/s, 5%=8.7m/s

! Chicago-OHare Intl AP_IL_USA Extreme Annual Temperatures, Max Drybulb=35.7°C Min Drybulb=-24.2°C

 

! Chicago-OHare Intl AP_IL_USA Annual Heating Design Conditions Wind Speed=4.9m/s Wind Dir=270

! Coldest Month=JAN

! Chicago-OHare Intl AP_IL_USA Annual Heating 99.6%, MaxDB=-20.6°C

SizingPeriod:DesignDay,

 Chicago-OHare Intl AP Ann Htg 99.6% Condns DB, !- Name

     -20.6,       !- Maximum Dry-Bulb Temperature {C}

     0.0,        !- Daily Temp Range {C}

     -20.6,      !- Humidity Indicating Conditions at Maximum Dry-Bulb

     98934.,     !- Barometric Pressure {Pa}

     4.9,        !- Wind Speed {m/s} design conditions vs. traditional 6.71 m/s (15 mph)

     270,        !- Wind Direction {Degrees; N=0, S=180}

     0.00,       !- Clearness {0.0 to 1.1}

     0,          !- Rain {0-no,1-yes}

     0,          !- Snow on ground {0-no,1-yes}

     21,         !- Day of Month

     1,          !- Month

 WinterDesignDay,!- Day Type

     0,          !- Daylight Savings Time Indicator

     WetBulb;    !- Humidity Indicating Type

 

!! Chicago-OHare Intl AP_IL_USA Annual Heating 99%, MaxDB=-17.3°C

SizingPeriod:DesignDay,

 Chicago-OHare Intl AP Ann Htg 99% Condns DB, !- Name

     -17.3,      !- Maximum Dry-Bulb Temperature {C}

     0.0,        !- Daily Temp Range {C}

     -17.3,      !- Humidity Indicating Conditions at Maximum Dry-Bulb

     98934.,     !- Barometric Pressure {Pa}

     4.9,        !- Wind Speed {m/s} design conditions vs. traditional 6.71 m/s (15 mph)

     270,        !- Wind Direction {Degrees; N=0, S=180}

     0.00,       !- Clearness {0.0 to 1.1}

     0,          !- Rain {0-no,1-yes}

     0,          !- Snow on ground {0-no,1-yes}

     21,         !- Day of Month

     1,          !- Month

 WinterDesignDay,!- Day Type

     0,          !- Daylight Savings Time Indicator

     WetBulb;    !- Humidity Indicating Type

 

! Chicago-OHare Intl AP_IL_USA Annual Humidification 99.6% Design Conditions DP=>MCDB, DP=-26.5°C

SizingPeriod:DesignDay,

 Chicago-OHare Intl AP Ann Hum_n 99.6% Condns DP=>MCDB, !- Name

     -19.7,      !- Maximum Dry-Bulb Temperature {C}

     0.0,        !- Daily Temp Range {C}

     -26.5,      !- Humidity Indicating Conditions at Maximum Dry-Bulb

     98934.,     !- Barometric Pressure {Pa}

     4.9,        !- Wind Speed {m/s} design conditions vs. traditional 6.71 m/s (15 mph)

     270,        !- Wind Direction {Degrees; N=0, S=180}

     0.00,       !- Clearness {0.0 to 1.1}

     0,          !- Rain {0-no,1-yes}

     0,          !- Snow on ground {0-no,1-yes}

     21,         !- Day of Month

     1,          !- Month

 WinterDesignDay,!- Day Type

     0,          !- Daylight Savings Time Indicator

     DewPoint;   !- Humidity Indicating Type

Design day “definitions” originate in the ASHRAE Handbook of Fundamentals. Prior to 1997, these conditions were described for winter and summer (heating and cooling). They were based on seasonal percentages.

 

EnergyPlus uses the design day object values and creates an entire day of weather data - this is described more fully in the Input Output Reference under the DesignDay object. The weather converter program assigns “SummerDesignDay” and “WinterDesignDay” day types by default - these day types influence “scheduling” of various elements. How to use these effectively is described during the DesignDay and Schedule objects discussions in the EnergyPlus Input Output Reference.

 

Beginning in 1997, and continuing (the latest version was published in 2009), the design condition data is based on annual percentages. In addition, only locations with long-term hourly observations data (on which to form the basis) are included.

[From ASHRAE Handbook of Fundamentals, 2009]

Design data based on dry-bulb temperature represent peak occurrences of the sensible component of ambient outdoor conditions. Design values based on wet-bulb temperature are related to the enthalpy of the outdoor air. Conditions based on dew point relate to the peaks of the humidity ratio. The designer, engineer, or other user must decide which set(s) of conditions and probability of occurrence apply to the design situation under consideration.

 

The 99.6% and 99% Heating conditions are often used in the sizing of heating equipment.

 

The 0.4, 1.0, and 2.0% dry-bulb temperatures and mean coincident wet-bulb temperatures (i.e., DB = >MWB) often represent conditions on hot, mostly sunny days. These are often used in sizing cooling equipment such as chillers or air-conditioning units.

 

Design conditions based on wet-bulb temperatures (i.e., WB = >MDB) represent extremes of the total sensible plus latent heat of outdoor air. This information is useful for cooling towers, evaporative coolers, and fresh air ventilation system design.

 

Design conditions based on dew-point temperatures (i.e., DP = >MDB) are directly related to extremes of humidity ratio, which represent peak moisture loads from the weather. Extreme dew-point conditions may occur on days with moderate dry-bulb temperatures, resulting in high relative humidity. These values are especially useful for humidity control applications, such as desiccant cooling and dehumidification, cooling-based dehumidification, and fresh-air ventilation systems. The values are also used as a check point when analyzing the behavior of cooling systems at part-load conditions, particularly when such systems are used for humidity control as a secondary function. Humidity ratio values are calculated from the corresponding dew-point temperature and the standard pressure at the location’s elevation.

 

The enthalpy design conditions (i.e. Enthalpy = > MDB) gives the annual enthalpy for the cooling season; this is used for calculating cooling loads caused by infiltration and/or ventilation into buildings. Enthalpy represents the total heat content of air (the sum of its sensible and latent energies). Cooling loads can be easily calculated knowing the conditions of both the outdoor ambient and the building’s interior air.