A barrier to the application of variable-speed components (drives, fans, pumps, and
compressors), which would be much more efficient and would enable new technologies, is the
requirement of a 42-volt electrical system in the truck. That, in turn, would require changing
every system on the truck that uses electricity, including lights, radios, and microprocessors. To
deal with the existing fleet and its 12-v system, in addition to future trucks with a 42-v system,
manufacturers would have to produce components for both voltage levels, and suppliers would
have to stock twice as many parts for many years. Ultimately, the costs of all those changes
would have to be absorbed by the trucking company and offset by the fuel savings.
Other factors that must be considered are operating costs related to weight, reliability, and
durability. If a new device (such as an auxiliary power unit, for example) adds weight to the
truck, there will be an equivalent reduction in payload, which reduces the revenue of the trucker.
Reduction of reliability and durability cannot be tolerated because of the potential added
expenses due to repairs and downtime. Owners must be presented with convincing data on
reliability before they will accept new technology.
While cost is a major concern for any new technology, a number of potentially energy-
saving advanced concepts also face technical barriers. A few examples are as follows:
A fundamental understanding of flow boiling mechanisms will be required to
develop a reliable and effective nucleate-boiling cooling system.
Effects on erosion and wear of components due to particles in nanofluids must
be understood before nanofluid technology will be accepted for improving the
heat-transfer characteristics of coolants and engine oils.
Fouling and pressure-drop issues must be addressed and resolved for the
application of advanced heat exchangers that use carbon foam technology.