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Conversions: Keeping it cool with refrigerated vans

Date: Wednesday, April 19, 2023   |   Author: Steve Banner

Electric light commercials are increasingly making their presence felt, with supermarket home delivery fleets deploying them in refrigerated guise in growing numbers. 

Last year saw Asda put its first all-electric model into service. With an insulated body built by Paneltex and a GAH fridge unit, it is based on a Maxus eDeliver 9 and can transport 111 totes – home delivery crates – containing chilled, ambient and frozen goods.

More all-electric models have joined the fleet since then.

Going zero-emission spells no tailpipe emissions, a reduced carbon footprint, and means the operator will not face daily charges imposed by urban clean air zones. Because electric vehicles run quietly out-of-hours deliveries become more feasible, although enough artificial noise must be generated to warn late-night cyclists and other vulnerable road users of their presence.

Basing a refrigerated vehicle on an electric platform imposes particular challenges however, not the least of them the extent to which powering an electric fridge unit will reduce its range.

“If you are on multi-temperature multi-drop work during summer in a big city, then you could find it falls by 20%, and possibly by as much as 30%,” says Paneltex managing director, Chris Berridge. In that sort of environment the fridge has to work that bit harder to ensure the load doesn’t start to defrost, and consumes more energy as a result.

On the face of it, matters should improve in bitterly cold winter weather because the fridge faces less pressure. The driver will need to turn up the in-cab heater and switch all the lights on as it gets dark earlier however, so the range is impacted again.

Berridge believes one of the best ways of ensuring that the fridge runs as efficiently and frugally as possible is to ensure that the cargo area is properly insulated. “The doors should be designed in such a way that drivers are encouraged to close them when they’re making deliveries rather than leaving them wide open,” he adds.

It is a view shared by Sean Clifton, Asda’s senior manager, national fleets and carriers. “Electric vans need more effective insulation and door systems as well as a very robust fridge,” he observes.

Their doors should also be equipped with air curtains rather than strips of tatty-looking PVC to keep the cold air in and heat and dust out, suggest some body builders.

At around £200 for each van door they are fitted to, air curtains are roughly double the price of a PVC strip curtain and can reduce the height of a door aperture by around 100mm. However they do not impose any more of a weight penalty than PVC does.

A big advantage of air curtains, say their advocates, is that they are tamper-proof. The difficulty with PVC strips is that drivers get tired of having to push their way through them – if you wear glasses then you can guarantee that the strips will knock them off your face regularly – so they tie them together to keep them out of the way.

As a consequence they are rendered ineffective.

By contrast, air curtains are easy to walk through, and your glasses will stay in place.

Air curtains draw energy from the battery, but leading supplier Brightech argues that any power loss is more than offset by the improvement in insulation they deliver. They have to be aligned correctly when they are installed though, so they do not keep running when the door is closed.

Up until recently, none of these considerations were as important as they are now, says Berridge. 

“Because diesel engines are so powerful the answer to any concerns about temperature maintenance was simply to fit an oversized fridge unit,” he comments. “These days you have to think differently.

“Remember that the energy density of batteries is two orders of magnitude less than the energy density of diesel fuel,” Berridge remarks.

It is of course possible to fit a separate battery solely to power the fridge rather than rely on the traction batteries. “We’ve looked at doing that, but it adds weight,” he observes.

Minimising weight is vital for home delivery work he adds, even though a government concession allows an electric 3.5-tonner to be uprated to 4.25 tonnes to compensate for the burden imposed by the battery pack, and driven on a car driver’s licence. 

“The home delivery companies are so weight-conscious that they’ll even take out a van’s passenger seat to save a few kilos,” says Stephen Williams, UK sales manager for transport refrigeration giant Thermo King. “They take the view that if their vehicles don’t have the capacity to transport ten more bags of groceries then that’s lost profit.

“They weigh every additional item that is fitted to a van, and installing a separate battery pack is like fitting another fridge so far as weight is concerned,” he adds.

The best approach therefore is to draw power from either the vehicle’s low-voltage or its high-voltage electrical system, says Berridge.

Choosing the former route is easier, but low-voltage fridge motors are not especially efficient, he points out. Going the latter route allows you to install a more-efficient fridge unit, but means you have to overcome a variety of barriers thrown up by vehicle manufacturers who are not notably keen on third parties going anywhere near a light commercial’s high-voltage electrics.

“You have to jump through hoops if you wish to do so,” says Williams.

Doing so may be essential if you are transporting frozen goods. Low-voltage fridges can handle chilled work, but asking them to maintain the temperature of fully-frozen loads is more problematic, says Berridge.

“This is why it is so important for body builders to work in harmony with chassis manufacturers,” he comments.

Paneltex products will be on display at this month’s Commercial Vehicle Show (National Exhibition Centre, Birmingham, 18–20 April). 

The line-up will include a left-hand drive Ford E-Transit capable of transporting chilled and ambient goods with a lightweight body designed for use by a grocery picking centre. On show too will be a right-hand-drive E-Transit able to tackle chilled, frozen and ambient work and intended for home delivery runs direct from a supermarket.

Both vehicles will be fitted with GAH fridge units.

Says Berridge: “At Paneltex we’ve always been interested in electrification and emissions reduction. Each electric vehicle we’ve produced has taken the industry a step closer to zero-emission cold chains.

“I’m really pleased we’re at the forefront of the movement towards greener options.”

One way of saving weight without compromising efficiency is to exclude timber from composite panel construction. It is a route pursued by CoolKit – What Van? Converter of the Year for 2023 – and the average payload of the fridge vans it turns out is up by 5% as a consequence, it reports.

Such a change helps to reduce deforestation. Improving vehicle payloads goes some way towards reducing highway congestion and thus emissions, the business argues, because fewer vans are needed to deliver the same amount of goods.

The UK’s leading producer of refrigerated van conversions, CoolKit can now turn out well over 1,500 conversions annually. Its list of options includes air curtains.

Recent products include an all-electric milk float with a 200-mile range between recharges, using a Maxus eDeliver 3 as a platform. Four of them have gone into service with The Modern Milkman; a far cry from the lead-acid-battery-powered milk floats that were a familiar sight every morning not so long ago.

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