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Solar Radiation Unit Conversions

download Excel spreadsheet with macro here.
        (this spreadsheet converts between sky cover, sunshine, and solar radiation in any of three units.)

1 BTU = 251.9958 Calorie
1 BTU = 1055.056 Joule
1 BTU = 1055.056 Watt-sec

1 Langley = 1 Cal/cm2
1 Calorie = 4.1868 Joule
1 Watt = 1 Joule/sec
1 Watt-sec = 1 Joule

1 Watt/m2 = 0.085985 Lang/hour       (see Conversion Sequence 1, below)
1 Lang/hour = 11.6300 Watt/m2         (see Conversion Sequence 1, below)

1 Langley = 41868 Joules/m2             (see Conversion Sequence 2, below)
1 Langley = 41868 Watt-sec/m2         (see Conversion Sequence 2, below)

1 Watt/cm2 = 3170 BTU/ft2-hour        (see Conversion Sequence 3, below)
1 Watt/m2 = 0.3170 BTU/ft2-hour       (see Conversion Sequence 3, below)

1 Langley/day = 0.484583 Watt/m2           (see Conversion Sequence 4, below)
1 Langley/day = 0.153613 BTU/ft2-hour     (see Conversion Sequence 4, below)
1 Watt = 3.41216 BTU/hour                     (see Conversion Sequence 5, below)


Conversion details are below, or download a pdf of this entire page here.

Conversion Sequence 1:

solar conversion sequence 1


Conversion Sequence 2:

solar conversion sequence 2


Conversion Sequence 3:

solar conversion sequence 3
 


Conversion Sequence 4:

solar conversion sequence 4


Conversion Sequence 5:

solar conversion sequence 5

.........


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