Conversion of Energy units

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Energy Conversion Tables and Information

Conversion Tables	Calorific Values	Emissions
Other Gas Information	Fuel Comparison Information

Pressure	N/m²	bar	mbar	mm wg	kPa/cm²
1 N/m² = 1 Pa =	1	10-5	10-2	0.102*	1.02 x 10-5
1 bar =	105	1	1000	10200*	1.020
1 mbar =	100	10-3	1	10.2*	1.02
1 mm wg* =	9.81	9.81 x 10-5	0.0987*	1	0.0001
10 mm wg* =	1mbar

Heat	kW	W = J/s	MJ/h	kcal/h
1 kW =	1	1000	3.6	860
1 W = 1 J/s =	0.001	1	3.6 x 10-3	0.86
1 MJ/h =	0.2778	277.8	1	238.8
1 kcal/h =	1.163 x 10-3	1.163	4.1868 x 10-3	1
Energy	kWh	MJ	J=Ws	kcal
1 kWh =	1	3.6	6.6 x 106	860
1 MJ =	0.2778	1	106	238.8
1J = 1 Ws =	2.778 x 10-7	10-6	1	2.388 x 10-4
1 kcal=	1.163 x 10-3	4.1868 x 10-6	4.1868 x 103	1

Calorific Value	MJ/m3	kcal/m3	Btu/ft3	Thermie/1
1 MJ/m3 =	1	238.846	26.8392	2.38927 x 10-4
1 kcal/m3 =	0.0041868	1	0.11237	1.00034 x 10-6
1 Btu/ft3 =	0.0372589	8.89915	1	8.90216 x 10-6
1 Thermie/1 =	4.18538 x 103	9.99662 x 105	1.12332 x 105	1
Therms/UK Gal =	2.3208 x 104	5.54314 x 106	6.22884 x 105	5.545

Volume	m3/h	L/h	UK gal/h	ft3/h
1 m3/h =	1	1000	220	35.3147
1 1/min =	0.06	60	0.22	2.119
1 ft3/s =	101.94	101938	2.24238 x 104	3600
1 UK Gal/s =	16.37	16366	3600	4.459 x 10-5

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Calorific Values
Commerical Propane	19,900 Btu/lb net and 21,500 gross.
	11,000 kcal/kg net and 11,900 gross.
Commercial Butane	19,700 Btu/lb net and 21,200 gross.
	10,900 kcal/kg net and 11,800 gross
UK Natural Gas is typically	47.32 MJ/kg net and 52.41 MJ/kg gross.
	34.88 MJ/m3 net and 38.63 MJ/m3 gross.

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Emissions

For natural gas

100ppm NOx at 15%O2 equates to 171 mg/MJ th [netCV] or 205 mg/m3 at 15%O2 [NOx as NO2]

100ppm CO at 15%O2 equates to 104 mg/MJ th [netCV] or 125 mg/m3 at 15%O2

100ppm CH4 at 15%O2 equates to 59 mg/MJ th [netCV] or 71 mg/m3 at 15%O2

Concentration at reference conditions = Measured concentration x [20.9% - (%O2Ref)] ¸ [20.9% - (%O2 actual)]

Note Boilers and furnaces are measured at 3% oxygen and gas turbines at 15% oxygen.

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Other Gas Information
Net to gross heat inputs: the conversion factor varies by furl, for NG it is 1.11 and for Propane is is 1.08.
Thus 60 kW gross NG is about 54kW net.
In addition an appliance at 80% gross efficiency will be about 88% net efficiency.
Limits of Flammability	NG = 4.5 to 15%
	Propane = 2 to 10%
	Butane = 1.8 - 9%
Specific heat of NG is about 1.86 kJ/kG per ºC whilst that of water is about 4.18 kJ/kG per ºC.
Relative Density of NG is about 1.36m3/Kg [0.737 kg/m3] whilst that of air is about 2.26 m3/kg. [SG about 0.6].
100 ft3 NG = 30 kW [30.4] or 1 m3 NG = 10 kW [10.7].
Taking NG as 1040 Btu/ft3 or 38.78 MJ/m3 gross.
Dewpoint of combustion products is	59ºC for NG, 55ºC for LPG.
Theoretical combustion air requirements:	9.76 for NG and 24 to 25 for LPG
Stoichiometric dry flue gas concentration of CO2	11.9% for NG and 13.8 to 14% for LPG.

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Fuel Comparison Information
Fuel Price	Grace C/Gas oil	Grade G oil	Propane
p/litre	p/kWh (p/th)	p/kWh (p/th)	P/kWh (p/th)
8	0.75 (20.94)	0.70 (20.57)	1.14 (33.50)
10	0.94 (27.55)	0.88 (25.71)	1.43 (41.87)
12	1.13 (33.18)	1.05 (30.85)	1.71 (50.25)
14	1.32 (38.71)	1.22 (35.75)	2.00 (58.62)
16	1.50 (43.96)	1.40 (41.03)	2.29 (66.99)
18	1.69 (49.53)	1.57 (46.01)	2.57 (75.37)
20	1.88 (55.10)	1.75 (51.29)	2.86 (83.74)
22	2.07 (60.07)	1.92 (56.27)	3.14 (92.12)

1 therm = 29.31 kWh	1 litre Gas Oil = 10.6 kWh	1 litre Grade G oil = 11.4 kWh
1 litre propane = 7 kWh	1 tonne propane = 19,900kWh

To the best of our ability, the above, the above information is correct but TXFINITY takes no responsibility for errors in its use. If you see an error, please email us

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Conversion of Energy units

Compare energy units used around the world

Energy Conversion Tables and Information