Tactical Garbage to Energy Refinery (TGER) - Sustainable Biotechnology: Sources of Renewable Energy - page 99

23 May 08

Off Board Power(KW) Diesel Flow (GPH)

60 3

2.5

50

2

40

1.5

30

1

20

0.5

10

0

0 - 0.5

Fig. 9 Example test data (fuel/power over time)

fuel when running at high loads. The specifications for the Kohler 60 kW generator
used on the TGER rates the engine's fuel consumption at 4.6 gallons per hour (gph)
when less than 100% load. 100% load for the Kohler generator set using a 3-phase,
120/240 V 4P8 alternator at prime rating is 54 kW. The TGER maintained 50 kW
of off board power (usable power) for approximately 2 h. During that same time the
engine's diesel fuel consumption was on average 1.5 gph, a diesel fuel savings of
2.76 gph.
Figure 10 illustrates the power efficiency of the TGER. The yellow line rep-
resents all the power consumed by the TGER's subsystems and is referred to as
parasitic power. All remaining power generated by the TGER (50 kW) is available
for use by the customer, and is represented by the light blue line. To determine the
TGER's power efficiency (pink line), we divided the power available to the customer
(light blue line) by the total power generated (dark blue line). The TGER's average
power efficiency was approximately 77.37% during the recorded timeframe.
Figure 11 illustrates the TGER's ability to continue to conserve diesel fuel in
adverse environmental conditions. The generator exceeded the recommended load
of 54 kW and generated 55.5 kW of off board power while consuming only 2.5 gph
of diesel fuel. The most likely cause of the increase in fuel consumption from 1.5
to 2.5 gph was due to foreign debris (i.e. sand and dust) entering the system and
causing the gasifier filters to clog, thereby reducing the amount of syngas supplied
to the engine. This forced the engine to compensate by supplying more diesel fuel
into the engine in order to maintain 55.5 kW of off board power. Even under these
sub-optimal conditions, the TGER was able to conserve 2.23 gph of diesel fuel.
Table 3 shows data taken during field testing on 30 May 08 that was input into
the TGER Energy Conversion Model. The model calculates the percent contribution