Chiller thrillers

With cheap red diesel left on the shelf, many businesses running temperature-controlled trucks and trailers are moving to all-electric packages for their fridge engines.

Steve Banner reports

Cheap red diesel used to be the lifeblood of fridge engines. Last year saw its demise so far as the road transport industry is concerned – a long-heralded change that has prompted businesses running temperature-controlled trucks and trailers to consider other power sources.

Simply switching to white diesel instead is an option, but an expensive one. Nor does it address the criticism increasingly levelled at diesel donkey engines – that they are a source of NOx, particulate and CO2 emissions.

They also generate noise; bad news if you are attempting to make late-night deliveries to residential locations with slumbering householders in the vicinity.

Electric avenue

Some operators have concluded that the best bet is to move away from diesel fridges and go electric. By doing so, they can tap into an environmentally friendly source of energy.

Delivering supplies to some 1,550 restaurants across the UK, Martin Brower has decided to pursue that route.

It has acquired 24 temperature-controlled Gray & Adams semi-trailers on contract hire from Centurion Truck Rentals, each of which is equipped with a Carrier Transicold Vector eCool system.

A gearbox and generator mounted on the centre axle of the trailer’s tri-axle bogie

SWITCHED energy generated by the axle and brakes, which would otherwise be lost, into electricity. It is stored in an onboard battery and used to power engine-less versions of Carrier Transicold’s Vector HE 19 fridge.

When a trailer is parked it can be connected to a threephase electrical supply using a standard five-pin standby plug, which will recharge the battery in a couple of hours, says Carrier. Generating very little noise, the package is PIEK-compliant, which allows goods to be dropped off out-of-hours without causing a disturbance.

Working out of Martin Brower’s Hemel Hempstead distribution centre, the new trailers are being deployed on delivery routes in and around London. In service seven days a week, they are scheduled to clock up around 87,500 miles each annually.

Says Carrier Transicold’s UK sales and marketing director James Bell: “Vector eCool has been around in Europe for the past 10 years and we’ve been placing units into fleets and on the road for the past couple of years. More and more UK operators are using it.”

European trials

Thermo King has developed a similar package to eCool under the Advancer AxlePower banner in co-operation with BPW. It uses BPW’s ePower axle and can be combined with Thermo King’s Advancer-e electric fridge.

Three trailers employing Advancer AxlePower are now in service in the Netherlands with hauliers working for supermarket chain Albert Heijn. Thermo King hopes to see Advancer AxlePower in operation with at least two transport companies on this side of the North Sea by the end of this year, says UK sales manager Stephen Williams.

He does not deny that kitting out a fleet’s trucks and trailers with all-electric packages is an expensive exercise.

“A lot depends on the exact specification, but as a ballpark figure Advancer AxlePower will cost you €50,000 to €55,000 (£44,500 to £49,000),” he says.

Making such a change saves on the weight of a diesel engine and fuel tank, however, and there is no need to worry about replenishing the tank with costly diesel. The presence of an electric trailer axle has minimal impact on the tractor unit’s fuel consumption, says Williams.

Some operators favour a halfway house that allows diesel units to be retained but run electrically, an approach recommended by Swedish-owned Hultsteins.

It has developed an electro-hydraulic system called Ecogen, which employs a power take-off (PTO) from the truck’s engine to drive a generator that delivers a constant 400V at idling speeds. Using a five-pin plug, the generator can be connected to the motor of virtually every make of refrigeration unit that has an electric standby. The fridge can be mounted on a rigid or a trailer.

The latest version of Ecogen – Ecogen 2 – is fitted to five Mercedes-Benz Actros tractor units operated by nationwide catering supplies specialist Reynolds.

Reynolds’ head of national fleet Steve White estimates that each Ecogen 2 will save at least £5,000 in diesel costs annually. “It’ll take about two or three years to cover the front-end cost of the units,” he predicts.

Ecogen 2 is easier to fit than Ecogen and runs cooler because of the way it has been redesigned, says Hultsteins’ UK MD, Graham Usher. “We’ve changed the hydraulic block, the routing of the pipes and their diameter,” he says. “The capital cost is £15,000 to £16,000. It’s designed for a 12-year working life and only costs around £150 per year to maintain,” he adds. “We offer it at 400V/50Hz but it can also operate at 400V/60Hz, which gives you a 10% to 12% increase in cooling capacity.”

Fitting a PTO costs approximately £1,200 and can be a challenge with some makes and models of tractor, he warns.

Easy bolt-ons

Scanias, Volvos and Renaults all have the necessary timing gear in their engines, says Usher, so a PTO can be bolted on easily. With other brands a PTO may have to be specified when the truck is ordered; retrofitting is likely to involve an extended workshop visit.

If a trailer with a diesel-fired fridge is coupled to a tractor without Ecogen 2, then it can still function. All the operator needs to do is fill the diesel tank and start the engine.

Carrier Transicold offers a rival PTO-powered package called Eco-Drive. Thermo King has one available under the Frigoblock banner that is alternator driven and uses an inverter to deliver a constant voltage.

Hultsteins can also supply Ecofridge, a purely hydraulic refrigeration system. It too depends on an engine PTO, but in this case it is used to run a belt-driven constantflow hydraulic pump, which in turn powers the Hultsteins refrigeration unit.

If the engine is switched off and the vehicle is parked overnight with no power supply it can be plugged into to allow the electric standby to be used. Hopefully the operator will have specified Intelli Start, which starts the engine automatically in order to trigger the fridge unit if the load area’s temperature rises above a certain point, then switches the engine off automatically once the correct temperature has been achieved.

The device includes an immobiliser, designed to prevent a thief from stealing the vehicle even if the engine is ticking over.

An onboard battery pack is another way of keeping a fridge operational while the vehicle is stationary, though not necessarily all night. The one fitted to Advancer AxlePower can keep a parked trailer’s refrigeration system running for up to five hours, says Thermo King.

Run a fridge off a PTO and the truck will burn more fuel. The consumption penalty is modest however, argues Hultsteins. A 6x2 tractor covering 100,000 miles annually at an average 11mpg might consume an extra 572 litres, it contends. Bear in mind, though, that a diesel-powered fridge on a trailer operating for 2,500 hours annually can burn a whopping 7,500 litres of fuel and emit almost 20 tonnes of CO2 per year.

THE SKY’S THE LIMIT

One way of reducing the amount of fuel refrigeration systems consume is to install solar panels on the roof of the truck or trailer’s body, Hultsteins points out. Using the electricity they produce to help power the fridge could save roughly 600 litres per year depending on the size of the vehicle, says the company.

Like truck manufacturers, refrigeration system developers are examining the potential of hydrogen fuel cells. Last September’s IAA Transportation show in Hanover, Germany, saw Carrier unveil a concept package developed in conjunction with Bosch and PowerCell Sweden with a fuel cell at its heart.

An electric power distribution unit is used to convert the DC current provided by the fuel cell into the AC current required by the fridge. The hydrogen tanks can be refilled in about the same time as a diesel tank, says Carrier Transicold, and offer a similar range.

Comments Carrier Transicold vice president and general manager Victor Calvo: “We’re committed to exploring every avenue to reduce emissions and deliver better sustainability for our customers – and hydrogen fuel cell technology is extremely exciting.” n

Northern Ireland’s McBurney Transport Group has come up with another application for solar panels. It is having 146 refrigerated semitrailers fitted with a small 50W panel apiece from Genie Insights.

The trailers all have diesel-powered fridge units. If any of them are parked up for a while, then the panel ensures that the unit’s battery will not go flat, and will always contain sufficient energy to start the diesel motor. McBurney’s opted for the panels after a 12-month trial with one on a trailer that went all over the UK and Ireland, including in bad winter weather with short daylight hours.

Says McBurney fleet manager Sammy Hamill: “We were surprised to see how such a simple and cost-effective solution could provide the answer to the battery-related issues we know are becoming increasingly common in the refrigerated transport industry.”