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    Solar Data - Bristol, TN


    Average Climate Conditions
    Solar Radiation Data
    Altitude and Azimuth of the Sun


    Average Climate Conditions
        Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
    Element
    Units                          
    Average Temperature °F 34.0 37.4 47.2 55.2 63.4 71.1 74.4 73.6 67.9 56.7 47.0 38.2 55.5
    Daily Minimum °F 24.3 26.8 35.4 43.0 51.6 59.9 64.1 63.1 56.6 44.2 35.9 28.2 44.4
    Daily Maximum °F 43.7 48.0 58.9 67.4 75.2 82.2 84.6 84.1 79.1 69.1 58.2 48.1 66.6
    Record High °F -21 -5 -2 21 30 38 45 43 34 20 5 -9 -21
    Record Low °F 79 80 85 89 92 97 102 101 100 90 81 78 102
    Heating Degree Days note a 961 773 552 298 121 6 0 0 44 280 540 831 4406
    Cooling Degree Days note a 0 0 0 0 71 189 291 267 131 23 0 0 972
    Average Humidity Ratio note b 0.33% 0.35% 0.47% 0.61% 0.92% 1.22% 1.39% 1.37% 1.12% 0.72% 0.52% 0.39% 0.78%
    Average Wind Speed mph 6.3 6.7 7.1 6.9 5.3 4.7 4.2 3.9 4.2 4.6 5.6 6.0 5.4
    Clearness note c 44% 46% 48% 51% 51% 53% 51% 52% 51% 51% 45% 43% 50%


    Note:
    1. Heating and cooling degree days calculated from 65 degree (F) base.
    2. expressed as pounds moisture per pound of air.
    3. Average atmospheric clarity to solar transmission, expressed as a percentage.

    Source:
  • National Renewable Energy Laboratory, Solar Radiation Data Manual for Buildings.


  • Average Incident Solar Radiation (Btu/sq.ft./day)
      Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
    Horizontal
    Global 690 920 1260 1600 1800 1940 1850 1710 1420 1130 760 610 1310
    Std Deviation 53 74 98 147 129 131 135 84 101 103 69 49 39
    Minimum 560 750 1130 1320 1580 1690 1630 1520 1260 1000 590 530 1240
    Maximum 780 1080 1490 1970 2050 2290 2100 1870 1670 1380 890 730 1400
    Diffuse 360 450 570 680 790 860 850 770 630 460 360 310 590
    North
    Global 220 280 350 430 530 600 560 470 390 300 230 190 380
    Diffuse 220 280 350 430 480 520 510 460 390 300 230 190 360
    East
    Global 440 560 740 900 970 1010 960 910 800 690 480 390 740
    Diffuse 260 330 430 520 580 620 600 560 480 370 280 230 440
    South
    Global 960 1020 1040 920 770 710 730 870 1020 1190 1020 930 930
    Diffuse 350 410 480 520 540 550 550 560 520 460 370 320 470
    West
    Global 450 590 760 910 970 1040 1010 970 840 710 500 410 760
    Diffuse 260 340 430 520 590 630 620 570 490 380 280 230 440


    Average Clear Day Incident Solar Radiation (Btu/sq.ft./day)
      Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
    Horizontal Global 1050 1400 1840 2270 2520 2600 2520 2280 1910 1460 1080 930 1830
    North Global 200 260 330 430 570 680 620 490 370 290 220 190 390
    East Global 760 960 1170 1330 1400 1410 1370 1290 1150 950 760 680 1100
    South Global 1990 1980 1730 1300 960 820 870 1130 1510 1790 1880 1900 1490
    West Global 760 960 1170 1330 1400 1410 1370 1290 1150 950 760 680 1100


    Average Transmitted Solar Radiation (Btu/sq.ft./day)
      Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
    Horizontal
    Unshaded 460 630 890 1160 1310 1410 1350 1240 1020 800 520 400 930
    North
    Unshaded 150 190 240 300 350 390 370 320 270 210 160 130 260
    Shaded 130 170 220 270 320 350 340 290 250 190 140 120 230
    East
    Unshaded 300 400 530 640 690 720 680 640 570 480 330 270 520
    Shaded 280 360 470 570 610 630 600 570 510 440 300 250 460
    South
    Unshaded 710 740 710 590 470 430 450 540 680 850 760 700 640
    Shaded 690 690 580 410 340 350 350 380 520 760 730 680 540
    West
    Unshaded 310 410 540 650 690 740 720 690 600 500 350 280 540
    Shaded 290 370 480 580 610 650 630 610 530 460 320 260 480


    Shading Geometry in Dimensionless Units
    Window

    1

    Horizontal Overhang (h):

    0.434

    Verical Gap (v):

    0.299



    Note:
    • Incident and transmitted radiation values are based on 30-year (1961-1990) averages for each month.
    • For explanation of shading geometry, see solar_shading.asp

    Source:
  • National Renewable Energy Laboratory, Solar Radiation Data Manual for Buildings.


  • Altitude of the Sun
      15-Jan 15-Feb 15-Mar 15-Apr 15-May 15-Jun 15-Jul 15-Aug 15-Sep 15-Oct 15-Nov 15-Dec
    Time of Day
    4:00                        
    5:00       -11.4 -4.8 -2.5 -4.7 -9.4        
    6:00     -8.8 0.6 6.4 8.3 6.2 2.1 -3.0 -8.0    
    7:00 -8.2 -4.1 3.4 12.1 18.0 19.6 17.6 13.7 9.1 4.1 -2.0 -6.9
    8:00 3.0 7.5 15.1 24.1 29.9 31.4 29.4 25.6 21.0 15.3 8.9 3.9
    9:00 12.8 18.2 26.5 35.9 42.0 43.4 41.4 37.6 32.4 25.9 18.5 13.3
    10:00 21.4 27.7 26.8 47.1 53.7 55.3 53.3 49.1 42.8 34.9 26.6 21.2
    11:00 27.9 35.2 45.2 56.6 64.3 66.7 64.5 59.3 51.2 41.5 32.2 27.0
    12:00 31.7 39.8 50.4 62.5 71.5 75.3 73.1 66.2 55.9 44.7 34.8 29.9
    13:00 32.2 40.7 51.1 62.4 70.8 75.2 73.9 66.6 55.3 43.5 33.8 29.6
    14:00 29.3 37.6 47.0 56.3 62.7 66.4 66.1 60.2 49.7 38.4 29.4 26.0
    15:00 23.4 31.3 39.2 46.7 51.8 55.0 55.1 50.2 40.8 30.4 22.3 19.8
    16:00 15.3 22.5 29.3 35.5 40.0 43.1 43.3 38.8 30.1 20.5 13.3 11.5
    17:00 5.8 12.3 18.2 23.7 28.0 31.1 31.2 26.9 18.5 9.5 3.1 2.0
    18:00 -5.1 1.3 6.5 11.7 16.1 19.3 19.4 14.9 6.6 -2.3 -8.4 -9.1
    19:00   -10.8 -5.6 0.3 4.7 8.0 7.9 3.2 -5.6      
    20:00       -11.7 -6.4 -2.8 -3.1 -8.4        


    Azimuth of the Sun
      15-Jan 15-Feb 15-Mar 15-Apr 15-May 15-Jun 15-Jul 15-Aug 15-Sep 15-Oct 15-Nov 15-Dec
    Time of Day
    4:00                        
    5:00       68.6 62.2 58.3 58.7 64.6        
    6:00     86.1 77.9 71.1 67.0 67.7 73.8 84.0 94.7    
    7:00 110.2 102.7 95.0 86.7 79.4 75.0 75.8 82.5 93.0 103.7 111.7 114.0
    8:00 118.9 111.8 104.3 95.7 87.8 82.8 83.9 91.2 102.4 113.3 121.0 122.8
    9:00 128.8 121.9 114.8 106.0 97.1 91.3 92.6 101.0 113.2 124.5 131.7 132.9
    10:00 140.4 134.1 127.6 119.0 109.1 101.9 103.4 113.4 126.9 138.1 144.4 144.6
    11:00 154.0 148.8 144.1 137.5 127.7 118.4 119.8 131.3 145.2 155.0 159.4 158.3
    12:00 169.5 166.3 165.1 164.5 161.0 152.6 151.1 159.7 169.3 174.9 176.1 173.7
    13:00 186.0 185.5 188.9 196.8 205.9 208.7 201.7 196.5 196.0 195.6 193.3 189.5
    14:00 201.9 204.0 211.0 223.5 236.2 242.2 236.6 226.2 218.9 214.1 209.2 204.6
    15:00 216.1 220.0 228.7 241.7 253.2 258.4 254.5 245.0 236.1 229.2 222.9 217.9
    16:00 228.2 233.2 242.3 254.6 264.6 268.9 265.8 257.7 249.0 241.5 234.4 229.3
    17:00 238.5 244.1 253.3 264.8 273.7 277.4 274.7 267.7 259.5 251.7 244.2 239.1
    18:00 247.5 253.6 262.8 273.8 282.0 285.3 282.8 276.5 268.7 260.8 253.0 247.7
    19:00   262.4 271.8 282.7 290.4 293.3 291.0 285.1 277.7      
    20:00       292.0 299.4 302.0 299.7 294.2        


    Get the data in CSV format

    Note:

  • Altitude are listed in degrees above the horizon. Azimuth values are listed in degrees, referenced to East of North.
  • Negative values indicate the sun is below the horizon
  • For further information, see solar_alt-az.asp

  • Source:
  • U.S.Naval Observatory.




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