Cool vehicles 08 June 2012

Refrigerated vehicle systems continue to see improvements claimed to reduce fuel use, increase uptime, and improve chill-down and temperature stability. But there's more to this than meets they eye, says Brian Tinham

Any fleet engineer involved in temperature-controlled transport will tell you that there's much more to getting this right than simply choosing a fridge unit capable of doing the job – critical though that is. Other factors include the vehicle construction – in terms of its strength and rigidity, yes, but also its insulation, door openings, aerodynamics and protection against the rigours of real-world operation in and out of docks. Then there are the cool chain telematics, the practical add-ons that help to prevent fridge failures – and, for the fridge units themselves, the all-important breakdown support.

"It's the whole package that needs consideration," pronounces Paul Allera, head of fleet for chilled, frozen and ambient goods distribution specialist Fowler Welch. "There's very little bad equipment out there on the market, but what we're doing is working with manufacturers to reduce overall emissions, fuel usage and noise, while cutting whole life costs – including maintenance and breakdowns."

For Allera, that means looking at several factors – ranging from fridge faring designs capable of meeting the opposing requirements of evaporator cooling versus improving aerodynamics, to providing 'traffic light' readouts for drivers, showing fridge temperatures and fuel remaining. And he talks about improving the design and mounting of systems for trailer soft docking, as well as the usual floor strengthening.

Specifically, though, he makes the point that although vehicle manufacturers are working hard to improve engine efficiency and aerodynamics on everything from tractor units to vans – driven by evolving emissions regulations and the whole industry's thirst for reduced fuel costs – that's not always the case with fridge producers, some of whose units are still powered by Euro 3 diesel engines. Additionally, while many fridge makers now claim significant improvements, most cold chain fleets are tied into their cool-chain trailer telematics, which monitor temperatures and air flows. So it's not necessarily easy to test claims for improvements by changing fridge supplier, even as trailers come up for replacement.

"For example, we used to specify Thermoking and Carrier fridges, linked to Seven Telematics' Transcan temperature recording platform. But, following development work between Thermoking and our vehicle tracking system supplier Cybit a couple of years ago, recent trailer acquisitions have mostly used Thermoking fridges, because their iBox telematics – which links with the trailer DAS system – comes with the package. We didn't need to spec [or pay for] Transcan print units any more: we got trailer temperature profile data for customers over the web," explains Allera.

"But now I want to run trials for six months on a German-built single-compartment trailer to a different spec, along with Carrier Transicold's Vector 1550 fridge, to see if the improvements they claim work out as well as they say they will. However, while we can run with their telematics during the trial – they'll give us a temporary login – if we decide to adopt Carrier, we'll have to go back to buying Transcan telematics, too, until Masternaut [Cybit] complete the development they're currently doing with Carrier for a similar system."

For some, that would be enough to put them off. But as Allera says, he wants to check out the Carrier units, not least so that he can spec two fridge suppliers, if it works out. And part of that is about testing the after-sales story – not only the extended service intervals and claimed better reliability. "I want to know that when there are breakdowns, lead times are as good as they say they are. I also want to know that parts are available quickly – and at sensible prices."

Vehicle construction
The other big issue, however, remains bodybuilding, and improving factors ranging from aerodynamics to weight, robustness, insulation and internal flexibility. That's where sandwich panel construction and bonding methods come in for trailers and box bodies – and insulated GRP moulding designs for van conversions.

Paneltex's group operations manager Howard Charlesworth, who looks after larger refrigerated truck and trailer build, explains that, while there are generally practical limits to the fridge design, its location and aerodynamics (although Paneltex offers its Direct Air), choice of box materials and construction methods remain key to maximising payload and longevity, while minimising cold losses.

"There are many types of foam insulation, but we primarily use Dow's Styrofoam in three- or five-element vacuum sandwich panels with GRP, which is very strong and light," states Charlesworth. "Styrofoam may cost a little more than expanded polystyrene and similar materials, but it has better thermal efficiency."

Those panels make up the walls, the bulkhead and the floor, with aerospace technology bonding for strength, and extra reinforcements in the form of platform cross members, usually fabricated from composite or plywood. That leaves the doors and door seals.

"On today's cold boxes, the only moving parts are the doors, and everyone judges us on those, because they are what prevent the loss of all that expensively generated cold air," comments Charlesworth. "So, like most of this industry, we use the same construction, with rubber perimeter seals and triple-leaf door gaskets... There are also things you can do with transparent strip curtains and triple doors to limit air escape during drop-offs."

As for vans, Dave Evenett, Paneltex and Somers group sales manager, says it's a similar story, except that the issue is generally less around strength – since that's the job of the van shell – and more about the construction of the insulation and sealing systems.

"We mostly convert mid wheelbase, high-roof 3.5-tonne Transits, Crafters and Sprinters, as well as some car-derived vans, using our own press panel kits," explains Evenett. "They're insulated with Styrofoam, and we use a long-lasting wet glass fibre overlay and resin finish to give a complete seal. We also provide glass fibre frameworks and insulation for the door apertures, and patented foam-injected modular doors."

Evenett advises owner-operators and fleet mangers to watch for details, such as ATP type approvals and the relevant insulation values, which vary considerably, according to conversion specialists' approaches. He also draws attention to conversions requiring side doors – making the point that the preferred option is to match the existing van profile and door systems – release button, central locking and light dimmer – without interrupting the CANbus or compromising the vehicle warranty.

Tesco chooses Carrier for 15.65m reefers
One of the UK's first 15.65 metre refrigerated trailers has been delivered to the Tesco fleet, fitted with Carrier Transicold's Vector 1850 MT (multi-temperature) low-noise fridge unit. Another 24 of the triple-compartment Gray & Adams extended length semi-trailers are due for delivery shortly.

"The beauty of this technology is that it is flexible [for] a wide range of trailer specifications, be it single, double-deck or these new longer length trailers," comments John Forster, sales director at Carrier Transicold UK.

He explains that to accommodate the additional 2.05 metre trailer length, Carrier had to modify the refrigeration equipment with a longer wiring loom that connects the nose-mounted unit to the evaporators and temperature sensors. However, he also says that the unit was readily adapted, because of its high capacity and quick pull-down power.

Just as important, the Vector 1850 uses Transicold's E-Drive technology, with an electric motor to drive the compressor and condenser fans in place of the conventional belt-driven diesel engine arrangement.

"The Carrier Transicold UK team has supported us in developing suitable refrigeration options in the past for our single and double-deck trailers so, naturally, we looked to them for this new venture," states Cliff Smith, fleet engineering manager at Tesco.

Cryogenic refrigeration from BOC
Industrial gases specialist BOC has begun trials of an in-transit refrigeration system, dubbed Frostcruise, which, it says, provides an environmentally friendly, efficient and reliable alternative to diesel-powered fridges.

Developed by BOC's parent company Linde Group, it uses the cryogenic effect of liquid nitrogen at -196°C to produce rapid and evenly-distributed temperature drops. Frostcruise does not rely on engines for compressor cooling, so is much quieter and runs independently in the event of a breakdown.

BOC business development manager Cedric Hanson says it comfortably maintains accurate product temperature throughout a truck compartment, even during multiple delivery stops, and offers a much lower carbon footprint than conventional kit.

"Frostcruise represents a major development for the food distribution industry," comments Hanson. "[It] could transform refrigerated transport of chilled and frozen perishable items by road."

MacFood Services, a food processor and distributor to the quick service restaurant industry in Malaysia, has recently taken delivery of a fleet of 14 Frostcruise equipped trucks. "Frostcruise has proven to meet our very demanding specifications on temperature," comments Viktor Sim, deputy managing director. "It has also coped admirably with the demands of maintaining very cold temperatures despite multiple delivery stops ... in extremely hot and humid climate conditions."

Author
Brian Tinham

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