22
Table 6 Baseline Annual Heating/Cooling Energy Use and CO
2
Emissions for 100% Market Penetration by Alternative
Technologies
Technologies
a
Energy Usage
Petroleum
Technology
(10
12
Btu)
(10
3
gal)
CO
2
Emissions
(10
3
tons)
Truck engine idling
107.5
838,140
9,597
Direct-fired heater plus idle cooling
64.7
504,433
5,764
Direct-fired heater plus thermal
storage cooling
storage cooling
10.2
79,197
907
Auxiliary power unit
19.3
150,860
1,727
Truck stop electrification
34.2
2,127
2,504
a
Assumes 458,000 trucks, with 85 days of heating at 10 h/d and 218 d with average
cooling at 4.5 h/d. Electrification assumes electrified truck stops (hot-bunked) to allow
usage by all trucks.
cooling at 4.5 h/d. Electrification assumes electrified truck stops (hot-bunked) to allow
usage by all trucks.
5.2 Summary
Truck engine idling consumes significant amounts of fuel to provide heating in the winter
and cooling in the summer. Many fuel-efficient options are available to provide heating and
cooling without resorting to idling. Promising options include (1) direct-fired heater for
cab/sleeper heating, with or without storage cooling; (2) auxiliary power units; and (3) truck stop
electrification. Along with truck stop electrification, electricity-based devices in the truck (for
example, those supplied by SCS/Frigette) would be needed. Each option has benefits and
drawbacks.
cooling without resorting to idling. Promising options include (1) direct-fired heater for
cab/sleeper heating, with or without storage cooling; (2) auxiliary power units; and (3) truck stop
electrification. Along with truck stop electrification, electricity-based devices in the truck (for
example, those supplied by SCS/Frigette) would be needed. Each option has benefits and
drawbacks.
The direct-fired heater is very efficient (about 80%, compared with only 11
-
15% for truck
idling) because it simply indirectly heats the air that enters the cab/sleeper area. Net energy
conversion efficiency of electrification (33%) is lower than that of the direct-fired heater, and the
market for electrification is limited to the available spaces, but a complete range of services is
provided. Electrification would most likely be successful over heavily traveled routes, where a
trucker could be sure of finding an electrified stop when he or she needed it. Auxiliary power
units are very efficient and they provide all necessary services at any location. A drawback of
direct-fired heaters is that they do not provide air-conditioning or electric power. Another
drawback is that they need electrical power, and so truckers will be concerned that they will not
have enough battery capacity to restart the engine, especially during cold weather. This option
has had limited market penetration in the past. But direct-fired heaters are small and relatively
inexpensive, and thermoelectric power-conversion devices are under development that promise
to help reduce their electricity consumption.
conversion efficiency of electrification (33%) is lower than that of the direct-fired heater, and the
market for electrification is limited to the available spaces, but a complete range of services is
provided. Electrification would most likely be successful over heavily traveled routes, where a
trucker could be sure of finding an electrified stop when he or she needed it. Auxiliary power
units are very efficient and they provide all necessary services at any location. A drawback of
direct-fired heaters is that they do not provide air-conditioning or electric power. Another
drawback is that they need electrical power, and so truckers will be concerned that they will not
have enough battery capacity to restart the engine, especially during cold weather. This option
has had limited market penetration in the past. But direct-fired heaters are small and relatively
inexpensive, and thermoelectric power-conversion devices are under development that promise
to help reduce their electricity consumption.
If typical trucks average 1,830 h of idling annually, eliminating idling and installing and
operating direct-fired heaters during winter would save about 311 million gallons