1 ton of refrigeration = 3.42 KW
1 Btu/(h.ft©÷.¡ÆF) EQUALS 0.00568 kW/(m©÷.K)
1 Btu EQUALS 1055 Joules
One source provides conversion efficiencies of coal, wood, and fuel oil. They report that one ton of anthracite coal produces 25 million BTU or 7,326 KWh of electricity. They also report that 1 gallon of heating oil produces 138,690 BTU or 40.6 KWh. Wood pellets are said to produce 8,500 BTU/pound or 17,000,000 BTU/ton = 4,982 KWh. I am still trying to find the amount of C02 produced by these various forms of energy.
In terms of the effect upon the environment, one needs to put measures into C02 equivalents. C02 is the primary, but not the worst, of the greenhouse gasses. (Methane is said to be 21 times as potent in terms of its greenhouse effect.)
Note the following (from the DOE) "200 milion tons CO2 per year or the equivalent emissions from 40 500 MWe coal-burning power plants in the U.S. equipped with flue gas desulfurization and carbon dioxide scrubbing and compression systems", This implies 20 million KW production capacity = 200 million tons of C02/year or 1 KW annual capacity = 10 tons/year. This is roughly 1 kg of C02/KWH. But this is 11 times the Japanese estimate of 80 grams of C02 produced per KWH -- even counting that 40% of their power is nuclear. The higher estimate is consistent, however, with an estimate derived from nuclear power industry which compares C02 equivalents of coal, oil, gas, nuclear, PV, and wind. (Note that in terms of their greenhouse effect, CH4 is 21 times as potent as C02).
An interesting web page that allows one to estimate C02 equivalents of various sources and uses of power allows us to calculate the C02 equivalent of our house. This conversion program is found at the Forests Absorbing Carbon dioxide Emision (FACE) foundation . This will analyze C02 production equivalents of a variety of activities. Using this calculator, it estimates .63 kg/KHW for electricity production (in the Netherlands). Similarly, 100 therms of natural gas is 500 kg or 5 kg/therm. Since 1 therm is approximately 100,000 BTU = 29.3 KWh, this means that electricity is roughly 3.7 times as C02 intensive as natural gas for the same amount of energy. These are, obviously, tentative estimates and need to be confirmed elsewhere. Another conversion table from the deltaland trust gives comparable values (expressed in pounds of C02 per activity: 11.7 pounds/therm and 1.3 lbs/KWH. These ratios are consistent with the observation that heat production is roughly 3.3 times more efficient than electrical production.
Basic conversions are between BTUs and Kilowatt Hours. One KWH = 3,412 BTU. Natural Gas comes in Cubic Feet but is typically measured in Therms (about 100 Cubic Feet of Gas or 100,000 BTU).
| To Convert From | To | Multiply By |
| h = heat-transfer coefficient : | ||
| Pcu/(hr)(ft2)(¡ÆC) Kg-cal/(hr)(m2)(¡ÆC) G-cal/(sec)(cm2)(¡ÆC) Watts/(cm2)(¡ÆC) Watts/(in2)(¡ÆF) Btu/(hr)(ft2)(¡ÆF) Btu/(hr)(ft2)(¡ÆF) Btu/(hr)(ft2)(¡ÆF) Btu/(hr)(ft2)(¡ÆF) Btu/(hr)(ft2)(¡ÆF) Btu/(hr)(ft2)(¡ÆF) |
Btu/(hr)(ft2)(¡ÆF) Btu/(hr)(ft2)(¡ÆF) Btu/(hr)(ft2)(¡ÆF) Btu/(hr)(ft2)(¡ÆF) Btu/(hr)(ft2)(¡ÆF) Pcu/(hr)(ft2)(¡ÆF) Kg-cal/(hr)(m2)(¡ÆC) G-cal/(sec)(cm2)(¡ÆC) Watts/(cm2)(¡ÆC) Watts/(in2)(¡ÆF) Hp/(ft2)(¡ÆF) |
1 0.2048 7,380 1,760 490 1 4.88 0.0001355 0.000568 0.00204 0.000394 |
| k = thermal conductivity : | ||
| G-cal/(sec)(cm2)(¡ÆC/cm) Watts/(cm2)(¡ÆC/cm) G-cal/(hr)(cm2)(¡ÆC/cm) |
Btu/(hr)(ft2)(¡ÆF/in) Btu/(hr)(ft2)(¡ÆF/in) Btu/(hr)(ft2)(¡ÆF/in) |
2,903.0 694.0 0.8064 |
Return to Index
| To convert from the unit in the first column to the unit in the second, multiply by the conversion factor in the third column.
Example |
| To Convert | To | Multiply By |
| Btu/hr | Horsepower | 0.0003929 |
| Btu/hr | Gram-cal/sec | 0.07 |
| Btu/hr | Foot-pounds/sec | 0.2162 |
| Btu/hr | Watts | 0.2931 |
| Btu/min | Kilowatts | 0.01757 |
| Btu/min | Horsepower | 0.02356 |
| Btu/min | Foot-lbs/sec | 12.96 |
| Btu/min | Watts | 17.57 |
| Foot-pounds/min | Kilowatts | 0.0000226 |
| Foot-pounds/min | Horsepower | 0.0000303 |
| Foot-pounds/min | Kg-calories/min | 0.000324 |
| Foot-pounds/min | Btu/min | 0.001286 |
| Foot-pounds/min | Foot-pounds/sec | 0.01667 |
| Foot-pounds/sec | Horsepower | 0.000818 |
| Foot-pounds/sec | Kilowatts | 0.001356 |
| Foot-pounds/sec | Btu/min | 0.07717 |
| Foot-pounds/sec | Kg-calories/min | 1.01945 |
| Foot-pounds/sec | Btu/hr | 4.6263 |
| Horsepower | Kilowatts | 0.7457 |
| Horsepower | Kg-calories/min | 10.68 |
| Horsepower | Btu/min | 42.44 |
| Horsepower | Foot-lbs/sec | 550 |
| Horsepower | Watts | 745.7 |
| Horsepower | Foot-lbs/min | 33000 |
| Horsepower (boiler) | Kilowatts | 9.803 |
| Horsepower (boiler) | Btu/hr | 33479 |
| Horsepower (metric) | Horsepower | 0.9863 |
| Kilowatts | Horsepower | 1.341 |
| Kilowatts | Kg-calories/min | 14.34 |
| Kilowatts | Btu/min | 56.92 |
| Kilowatts | Foot-lbs/sec | 737.6 |
| Kilowatts | Watts | 1000 |
| Kilowatts | Foot-lbs/min | 44260 |
| Watt (international) | Watt (absolute) | 1.0002 |
| Watts | Kilowatts | 0.001 |
| Watts | Horsepower | 0.001341 |
| Watts | Horsepower (metric) | 0.00136 |
| Watts | Kg-calories/min | 0.01433 |
| Watts | Btu/min | 0.05688 |
| Watts | Foot-lbs/sec | 0.7378 |
| Watts | Btu/hr | 3.4129 |
| Watts | Foot-lbs/min | 44.27 |
| Watts | Erg/sec | 107 |
| Watts (absolute) | Btu (mean)/min | 0.056884 |
| Watts (absolute) | Joules/sec | 1 |
Another useful conversion table is by Salt Lake City Community College. This allows one to convert between metric and more conventional (at least in the US) systems.
For users of Palm Pilots, there is a useful calculator program (Parens) that has many useful conversion factors. Parens and the free version, Parens lite are wonderful utilities for the Palm.
Insulation is reported in R and U units: R units of resistance to heat flow = 1/r Units of heat conductance. Units of R versus 1/R are U . (Walls are reported in R, Windows in U).