Appendix II

Tables, Conversion Factors

Properties of various fuels

fuel	density	calorific value (kJ/kg)	ignitability	ignition temperature in air (°C)	stoichiometric air/fuel ratio (kg/kg)	methane no.
			(Vol % gas in air)
methane	0.72	50000	5.0...15.0	650	17.2	100
	kg/m³n
LPG	0.54 kg/l	46 000	2.0 . . .9.0	400	15.5	30
propane	2.02	46 300	2.0. . .9.5	470	15.6	35
	kg/m³ n
butane	2.70	45 600	1.5 . . .8.5	365	15.6	10
	kg/m³ n
petrol	0.75 kg/1	43 000	0.6 . . .8.0	220	14.8	-
diesel	0.85 kg/1	42500	0.6 . . .8.5	220	14.5	-
natural	0.83	57500	5.0 . . . 17.0	600	17.0	80
gas	kg/m³ n
biogas1	1.2	18000	5.0. . . 15.0	650	10.2	130
(60% CH4)	kg/m³ n

¹) H₂S content should be at 0.15 Vol % (1500 ppm), but never more than 0.5 Vol % (5000 ppm).

Other useful correlations

- Calorific value of biogas by methane content
100% CH₄: Hu = 36 000 kJ/m³ n = 10 kWh/m³ n
each 10% of CH₄ content in biogas: Hu = 3600 kJ/m³ n = 1 kWh/m³ n

Example:
65% CH₄: Hu = 23 400 kJ/m³n = 6.5 kWh/m³n

- Energy equivalents of biogas

1 kWh biogas =0.1 l diesel fuel =0.11 l petrol
1 m³ n biogas =0.6 l diesel fuel =0.67 l petrol
1 m³ n biogas = 1.5 kWh mechanical energy= 1.3 kWh electrical energy

- Pilot fuel requirement for diesel gas engine (at 20% of consumption in diesel fuel mode): 0.06 1/kWh
- Change (decrease) of engine performance with ambient conditions
- location altitude approx. 1% each 100 m above sea level
- pressure approx. 1% each 10 mbar below design conditions
- temperature approx. 1% each 5 °C above 20 °C
- rel. humidity approx. 2% each 10% above 65%
- Change of ambient pressure with location altitude approx. 10 mbar each 100 m

Metric conversion table:

Energy
	kcal	kWh	kJ	kNm
kcal	1	1.163*10-3	4.187	4.187
kWh	860	1	3600	3600
kJ	0.239	0.278	1	1
kNm	0.239	0.278	1	1

Pressure
	PA	bar	m WG	N/m²
PA	1	10-5	10-4	1
bar	105	1	10	105
mWG	104	0.1		104
N/m²	1	10-5	10-4	1

Power
	kcal/h	kW	kJ/h	HP*
kcal/h	1	1.163*10-3	4.187	1.6*10-3
kW	860	1	3.6*103	1.36
kJ/h	0.239	0.27*10-3	1	0.38*10-3
HP*	633	2.65*103	0.736	1
* 1 HP = 745.70 W, HP metric = 735.49875 W

Factor	Unit	Equivalents
Length:	m	1 m= 0.001 km
	= 100 cm = 1000 mm
Volume:	m³	1 m³= 1000 l
Time:	s	1 min= 60 s,
	1 h = 3600 s,
	1 d= 24 h,
	1a=365 d
Temperature: K	0 ºC = 273 K
	T [K] = 273 [K] + °C

Conversion of Sl units into British/American units

Combined measures can be converted by inserting the appropriate conversion factors into the original expression, e.g.:

BTU/h ft² F = 1055/(3600*0.0929*5/9) = 5 678 W/m² K

Sl (metric) to Brit./Amer.		Brit./Amer. to Sl (metric)
Length
1 cm	= 0.3937 in (inch)	1in	= 2.5400 cm
1 m	= 3.2808 ft	1ft	=12in= 0.3048 m
	= 1.0936 yards	1 yard	= 3ft= 0.9144 m
1 km	= 0.6214 mile (statute)	1 mile (statute)	= 1.60934 km
Area
1 cm²	= 0.1550 sq in	1 sq in	= 6.4516 cm²
1 m²	= 10.7639 sq ft		= 0.000645 m²
	= 1.1960 sq yards	1 sq ft	= 0.0929 m²
1 ha	= 2.471 acres	1 sq yard	= 9 sq ft = 0.836 m²
	= 10000 m²	1 sq mile	= 2.590 km²
		1acre	= 0.4047 ha
Volume
1 cm³	= 0.06102 cu in	1 cu in	= 16.3870 cm³
1 dm³	= 61.024 cu in		= 0.01639 dm³
1 l	= 0.03531 cu ft	1 cu ft	= 28.317 dm³
	= 61.026 cu in	1 cu yard	= 0.7646 m³
	= 0.21998 gal (Brit.)	1 gal (Brit.)	= 4.546 l
	= 0.26428 gal (Am.)	1 gal (Am.)	= 3.785 l
1 m³	= 35.315 cu ft	1 quarter (Brit.)	= 64 gal
	= 1.308 cu yards	.	= 290.9 l
	= 6.299 Petr. barrels	1 Petr. barrel	= 0.15876 m³
			=42gal
1 quart (Am.)	= 2 pints
			= 0.946 dm³
1 bushel (Am.)	= 35.2421
1 bushel (Brit.)	= 36.37 1 = 8 gal
1 Nm³	= 37.97 cu ft	1 cu ft	= 0.02635 Nm³
	(60°F, 30 in moist)	(60°F, 30 in moist)
1 Nm³	= 37.22 cu ft	1 cu ft	= 0.02687 Nm³
	(60°F, 30 in dry)	(60°F, 30 in dry)
Weight, mass, density
1 g	= 0.03527 oz (av)*	1 grain	= 0.0648 g
	= 15.432 grain	1 oz (av)*	= 28.35 g
1 kg	= 2.2046 lb (av)*	1 lb (av)*	= 16 oz
	= 0.0787 quarter (Brit.)		0.4536 kg
			= 7 000 grains
1 t	= 0.984 long tons	1 quarter (Brit.)	= 28 lb = 12.701 kg
	= 1.102 short tons	1 long ton (Brit.)	= 1016 kg
1 kg/m³	= 0.06243 Ib/cu ft	1 short ton (Am.)	= 2000 lb = 907.2 kg
		1 Ib/cu ft	= 16.0185 kg/m³
1 g/kg	= 7.0 grain/lb	1 grain/lb	= 0.1426 g/kg
I g/m³	= 0.437 grain/cu ft	1 grain/cu ft	= 2.2884 g/m³
1 g/m³	= 2.855 ton/sq mile	1 ton/sq mile	= 0.3503 g/m³
1 m³/hm³	= 0.0547 cbf/sq ft	1 cfm/sq ft	= 18.3 m³/hm³

* Avoirdupois (av), the generally accepted series of weight units based on a pound of 16 ounces and an ounce of 16 drams, as opposed to the troy system based on a pound of 12 ounces and an ounce of 20 pennyweights or 480 grains.

Velocity and flow
1 m/s	= 196.85 ft/min	1 ft/min	= 0.508 cm/s
1 km/in	= 0.6214 mph	I mph	= 1.60934 km/in
1 Kn	= 1.852 km/in	1 km/h	= 0.54 Kn
	= 0.514m/s		= 0.278m/s
1 m³/h	= 4.403 gal/min (Am.)	1 gal/min (Am.)	= 0.227 m³/h
	= 3.666 gal/min (Brit.)	1 gal/min (Brit.)	= 0.273 m³/h
1 m³/h	= 0.5886 cu ft/min	1 cu ft/min	= 28 317 1/min
		= 1.700 m³/h
1 kg/in	= 0.0367 Ib/min	1 Ib/min	= 27.216 kg/in
Power
1 W (Watt)	= 3.412 BTU/h	1 BTU/h	= 0.2931 W
1 kW	= 3412 BTU/h	1 HP	= 0.7457 kW
Enthalpy and entropy
1 kJ/m³	= 0.02684 BTU/ft3	1 BTU/ft3	= 37.26 kJ/m³
1 kJ/kg	= 0.43021 BTU/lb	1 BTU/lb	= 2.3244 kJ/kg
1 kJ/K	=0.5266 BTU/F	1 BTU/F	= 1.899 kJ/K
Pressure and force
1 N (Newton)	= 0.2248 lb (f)	1 lb (force)	= 4.448 N
1 N/m²	= 0.0209 Ib/ft2	1 Ib/in (psi)	= 6895 N/in2
(Pascal)			= 68.95 mbar
			= 703.1 mm H2O
1 bar	= 14.504 psi	1 Ib/ft2	= 47.88 N/m²
	= 29.530 in Hg		= 0.4788 mbar
	= 0.987 atm		= 0.0470 mm H2O
1 mbar	= 0.0145 psi	1 in H2O	= 249.08 N/m²
	= 0.0295 in Hg		= 2.4908 mbar
	= 0.4019 in H2O		= 25.4 mm H2O
	= 2.089 lb/ft2	1 in Hg	= 33.864 mbar
1 mm H2O	= 0.0394 in H2O	1 ft H2O	= 29.89 mbar
1 atm	= 14.696 psi	1 atm	= 1.013 bar
1 mm H2O/m	= 1.1993 in H2O/100 ft	1 ft H2O/100 ft	= 98.10 N/m²*m
1 N/m² m	= 0.1223 in H2O/100 ft	1 in H2O/100 ft	= 8.176 N/m²*m
1 mbar/m	= 0.442 psi/100 ft	1 psi/100 ft	= 2.262 mbar/m
Energy
1 J (Joule)	= 0.948 10-3 BTU	1 BTU	= 1.055 kJ
1 kJ	= 0.948 BTU	1 ft lb (force)	= 1.356 J
1 kWh	= 3414.5 BTU	1 HPh	= 2685 kJ
1 MWh	= 34.1297 therms	1 therm	= 0.1055 GJ
		(100 000 BTU)	(29.288 kWh)
Specific heat
1 kJ/kgK	= 0.2388 BTU/lb F	1 BTU/lb F	= 4.187 kJ/kgK
1 kJ/m³K	= 0.0149 BTU/ft3 F	1 BTU/ft3 F	= 67.070 kJ/m³K
Heat
1 kJ/m².	= 0.0881 BTU/ft2	1 BTU/ft2	= 11.357 kJ/m²
1 W/m²	= 0.3170 BTU/h ft2	1 BTU/h ft2	= 3.155 W/m²
1 W/m²K	= 0.1761 BTU/h ft2 F	1 BTU/f ft2 F	= 5.678 W/m²K
1 W/mK	= 0.578 BTU/h ft F	1 BTU/h ft F	= 1.7296 W/mK
	= 6.9348 BTU in/h ft F	1 BTU in/in ft2 F	= 0.1442 W/mK
1 m²K/W	= 5.6786 h ft2 F/BTU	1 h ft2 F/BTU	= 0.1761 m²K/W
1 mK/W	= 1.7296 h ft F/BTU	1 h ft F/BTU	= 0.5782 mK/W
	= 0.1442 BTU in/in ft2 F	1 h ft f/BTU*in	= 6.934 mK/W
Refrigeration
1 kW	= 0.2843 tons of refrigeration	1 ton of refrigeration	= 3.517 kW
Heating
1 kW	= 0.1019 HP (boiler)	1 HP (boiler)	= 9.809 kW
			= (33 475 BTU)
1 kW	= 14.22 EDR (steam)	1 EDR (equivalent
	= 22.74 EDR (water)	direct radiation)	= 70.34 W
	= 3412 BTU/h water	steam	= 43.97 W