11
Figure 4 Pony Pack Auxiliary Power Unit
(Reproduced with permission, Pony Pack,
Inc.)
(Reproduced with permission, Pony Pack,
Inc.)
Figure 3 Espar Heater (Courtesy of Espar Heater Systems)
existing air-conditioning system. APUs are
proven technology. For example, the "Napsac"
from Advanced Thermodynamics Corporation
(ATC) uses an 11-hp, 2-cylinder Detroit Diesel
engine that produces 3.5 kW of AC power at
115 V (ATC undated a). Cab/sleeper heat is
provided by an electric heater mounted in the
unit, and the engine coolant is circulated in the
same unit for additional heat. Another unit by
APC is equipped with a water brake to convert
mechanical (shaft) power to heat (up to
60,000 Btu/h; ATC undated c). A competing
unit, called the Pony Pack, is a 12-V unit (with
inverters available for 110-V needs). It uses a
2-cylinder diesel engine, an alternator, and an
air-conditioning compressor, all within an
proven technology. For example, the "Napsac"
from Advanced Thermodynamics Corporation
(ATC) uses an 11-hp, 2-cylinder Detroit Diesel
engine that produces 3.5 kW of AC power at
115 V (ATC undated a). Cab/sleeper heat is
provided by an electric heater mounted in the
unit, and the engine coolant is circulated in the
same unit for additional heat. Another unit by
APC is equipped with a water brake to convert
mechanical (shaft) power to heat (up to
60,000 Btu/h; ATC undated c). A competing
unit, called the Pony Pack, is a 12-V unit (with
inverters available for 110-V needs). It uses a
2-cylinder diesel engine, an alternator, and an
air-conditioning compressor, all within an
aluminum frame, that has been integrated with
the existing water, fuel, and electrical systems.
This commercial unit, which is available as an
option on some new trucks, keeps the battery
the existing water, fuel, and electrical systems.
This commercial unit, which is available as an
option on some new trucks, keeps the battery
and engine coolant warm and cools the cabin, so drivers avoid start-up problems. Manufacturer's
data on energy consumption and costs for this APU are presented in Appendix A. Actual test
data will be collected from a demonstration fleet of about 10 trucks in Texas (MSR 1999). One
advantage cited for APUs is that they can serve as survival systems in case of truck breakdown in
extreme weather conditions.
data on energy consumption and costs for this APU are presented in Appendix A. Actual test
data will be collected from a demonstration fleet of about 10 trucks in Texas (MSR 1999). One
advantage cited for APUs is that they can serve as survival systems in case of truck breakdown in
extreme weather conditions.
In the future, it might be possible to use a gasoline or diesel-powered solid oxide fuel cell
(SOFC) as the power source in an APU. BMW is currently doing research on an SOFC to replace
a car's battery and alternator (Neff 1999). DOE's Office of Transportation Technologies is
investigating the feasibility of an SOFC as an APU in trucks. No data are available at this early
concept stage.
a car's battery and alternator (Neff 1999). DOE's Office of Transportation Technologies is
investigating the feasibility of an SOFC as an APU in trucks. No data are available at this early
concept stage.