Energy related conversion factors
Conversion factors.
Power
1 horsepower = 736 watts
Energy
1 kilocalorie = 4190 joules
1 kilowatthour (kwh) = 3600 kilojoules = 859 kilocalories
1 m3 natural gas = 10 kwh (9,769 kWh)
1 barrel of oil = 1700 kwh
1 calorie (cal) = 4.184 J
1 British Thermal Unit (BTU) = 1055 J
Energy content of some fuels
| 1 kilogram of dry wood | 5,3 kwh | 19,0 mJ |
| 1 kilogram of coal | 8,1 kwh | 29,3 mJ |
| 1 cubic metre of natural gas | 8,8 kwh | 31,7 mJ |
| 1 litre of petrol | 9,1 kwh | 32,6 mJ |
| 1 litre of diesel-oil | 10,0 kwh | 35,9 mJ |
| 1 kilogram of hydrogen | 33,6 kwh | 120,8 mJ |
| 1 kilogram of Uranium 235 | 22,2 million kwh | 80,0 million mJ |
mJ = mega-Joules
Thermal energy content of 1 liter of petrol = 7800 kcal
Enough energy to bring more than 8 buckets of water of 10 liter from room temperature to boiling point.
Mechanical energy in 1 litre of petrol = 9.1 kwh
It takes 1 m3 of petrol to lift a Boeing of 334 ton from ground to 10 km altitude (ignoring horizontal speed, friction, efficiency engines)
1 kilo-calorie (kcal) is enough to lift a cow 1 meter.
Energy conversion
Maximum efficiency of transforming heat into mechanical energy is about 50% (Carnot formula: efficiency = (Thigh – Tlow) / Thigh )
A steam-turbine in a power plant has an efficiency of 45%
Maximum efficiency conversion of mechanical energy into electricity is up to 100%
A generator in a power plant has an efficiency of 95%
Maximum efficiency conversion of electricity into mechanical energy is up to 100%
The electric motor of the “Solar car” has an efficiency of 97%
Energy prices (Netherlands, 2012):
|
energy source |
price per unit |
price per kwh |
|
|
1 litre of petrol = 9,1 kwh |
€ 1,81 |
€ 0,20 |
|
|
1 m3 of natural gas = 8,8 kwh |
€ 0,65 |
€ 0,07 |
|
|
1 kwh electricity from the grid |
€ 0,22 |
€ 0,22 |
Humans:
1 adult male human is a chemical process that generates in rest on average 100 Watt surplus heat.
1 human can produce 100 Watt of useful labour during a longer period of time.
1 wildly dancing human can produce 400 watt of thermal energy.
During short periods of time human athletes can generate up to 800-1000 Watt.
Personal note: man, in his fifties in reasonable physical condition, on a hometrainer, can produce 120 Watt for 30 minutes at pulse 120. Sweating but not exhausted
1 barrel of oil = 8 years of human physical labor
1 kwh = 1 day of hard physical labor
Energy consumption average Dutch household (2.28 persons in 2008):
| electricity | 3560 kwh |
| natural gas | 1625 m3 |
| car | 1444 liter petrol |
Average distance car: 17400 km
Primary energy in power plant: 8900 kwh (efficiency 40%)
Converted into liter gasoline equivalent:
| lighting | 0.4 |
| Fridge, tv, washing, ironing, vacuum cleaning | 2.3 |
| heating, warm water, cooking | 4.3 |
| car | 4.0 |
Total 11.0 liter gasoline equivalent
These four categories in pie diagram:
Solar Energy
DeepResource 