25
To select the desired fuel, press the UP or DOWN keys until the desired fuel
appears on the top of the display and then press ENTER. The fuel selection
affects the following parameters: combustion efficiency, carbon dioxide
calculation and display of toxic gases in units other than PPM.
7) TEMPER. UNITS: The UP or DOWN keys toggle between °F (Fahrenheit) and
°C (Celsius). Stack temperature and ambient temperature will be displayed,
printed, and saved in the selected units.
8) MEAS. UNITS: When the cursor is blinking on this line, you can select any of
the following units of measurement for the toxic gases (CO, NO, NO
2
& SO
2
):
• PPM : Parts per million (volumetric)
• MGM : Milligams per cubic meter
• #/B : Lbs. (of pollutant) per million BTU of fuel
• GBH: Grams (of pollutant) per break horsepower-hour
To choose the desired emission units, toggle the UP & DOWN buttons until the
proper units are displayed. Then press the ENTER key. If you select GBH
(grams/brake horsepower-hour) as the desired units, you must not forget to set
the value of the (engine) thermal efficiency also! You can obtain this figure
from the engine's manufacturer specifications. It differs somewhat as a function
of engine type and load factor. (Typically, it is a number between 0.25 and
0.35). The ENERAC's default value is 0.30. If the thermal efficiency is not
known, it may be computed by using the engine's BSFC (brake-specific fuel
consumption-BTU/BHP-HR) as follows:
ENGINE EFFICIENCY = 2547/BSFC
NOTE: Emission units measurements in PPM, MGM, #/B and GBH are carried
out on a dry basis as required by the EPA’s 40CFR75 . (The ENERAC is an
extractive analyzer, whose conditioning system removes most of the water
vapor before the sample reaches the sensors).
NOTE: Values of emissions in #/B and GBH are fuel and CO
2 dependent.
The fuel parameters for certain typical fuels (i.e. the F- factors for anthracite,
etc.) used in the analyzer have been modified to be identical to those specified
in 40CFR60 Appendix A method 19 of the code of federal regulations. Consult
ENERAC, Inc., for details and correction factors.
NOTE: NO and NO
X emissions in #/B or GBH are computed as NO
2
!
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