For trucks carrying refrigerated loads, both the design and application of the refrigeration unit can have a significant effect on overall fuel usage. Small truck units are sometimes powered directly from the vehicle engine, while large truck and trailer units are powered by a stand-alone independent diesel generator. Simply replacing an older unit with a newer, more fuel-efficient diesel-powered unit will have an impact. Another alternative is to train staff in the efficient use of refrigeration systems to minimise heat loss (e.g. unnecessary and lengthy door opening). Several innovative approaches are under development, such as solar-powered trailers, grid-charged systems, fuel cell systems, hybrid systems and the use of liquid nitrogen technology.
In this area, Australia mostly adopts overseas-developed systems, so the availability of innovative and low-emissions systems depends on international product plans. Local suppliers indicate that power units using alternative power sources do not feature prominently in their current plans; however, efficiency-focused systems are available.
This is a long-term and ongoing opportunity as generators and/or trailers come due for replacement. More innovative technologies are yet to reach the commercialisation stage in Australia but viability depends on the price differential between diesel generation and alternative technology.
Greater fuel efficiency can be achieved by simply replacing old units with newer units, which will in turn reduce emissions. Emerging technologies are claimed to be less noisy, have lower maintenance costs (due to fewer moving parts), and may eventually be emissions free.
Key implementation considerations
Although the purchase of newer units and retro-fitting can be expensive, the capital cost of refrigerated transport equipment may account for less than 50% of its whole-of-life cost when maintenance and other operating expenses are taken into account. There are, however, some physical constraints to substituting diesel-powered units with alternative technology. For example, the trailer roof area limits the available power for solar PV, and the additional weight reduces fuel economy and the amount of cargo that may be carried.
Examples of implementation
Solar-powered refrigeration trailers
This academic report discusses the potential for solar-assisted refrigeration in freight, and notes past successes.
The report’s proposed photovoltaic system is capable of displacing 85% of the diesel used to refrigerate the trailer down to –18°C. The economics of this system are presently unattractive in Australia because diesel is relatively inexpensive compared to the capital outlay for photovoltaic cells.
The situation assessed in the study for Sainsbury’s in the UK is quite different (Section 4.3.3), where diesel fuel costs are higher—at the time of writing over $2.30 per litre—and temperatures are typically less extreme.
For more information, see Bergeron D (2001) Solar Powered Refrigeration for Transport Applications - A Feasibility Study, Final Report (Opens in a new window) PDF 1.1 MB.
This news article discusses the release of a diesel-electric technology-based refrigeration unit for trailers, along with claims of significant savings in operating costs (CCJ Digital 2010).
Carrier Transicold unveiled a new hybrid trailer refrigeration unit featuring next generation technologies. The Vector 6600MT unit provides high refrigeration capacity and delivers up to 20% greater fuel efficiency than its predecessor. By taking advantage of AC power, fuel is conserved, emissions are eliminated, noise is reduced and potential operating savings of 40–70% can be realised.
For more information, see CCJ Digital (2010) Carrier Transicold Introduces New Hybrid Refrigeration.
This news release details the presentation of a nitrogen-powered refrigerated trailer by MaxiTRANS, and the potential economic carbon and operational benefits that it brings.
Eco-Fridge, a liquid nitrogen–powered refrigerated trailer, is claimed to be the most advanced, silent running and emission-free unit for cost-effective temperature-controlled transport.
Capital and operating costs are currently being evaluated in field trials under Australian operating conditions. Indications from other locations are that operational savings compared to conventional refrigeration systems may be achievable.
For more information, see Truck World (2010) EcoFridge – 21st Century Trailer Refrigeration has arrived.
For the full report, see Fuel for Thought – Identifying potential energy efficiency opportunities in the Australian road and rail sectors (opens in a new window) PDF 1.5 MB.