Nitrogen could provide the new alternative for refrigerated transport – Words by Chris Mullett
The NACV Show in Atlanta proved interesting by way of innovation, with companies of all shapes and sizes portraying the move to electric vehicles or the use of hydrogen fuel cells as the next form of fossil-fuel replacement. But one new innovation took the interest of PowerTorque in the form of the latest prototype trailer engineering from American trailer builder Hyundai Translead.
In Australia we know of Hyundai light commercials and passenger cars, but this South Korean parent is also responsible for manufacturing trailers in North America, with Hyundai Translead claiming the lead in the market as the number one manufacturer in terms of volume. So, rather than thinking in terms of the major trailer companies being well known names such as Wabash or Great Dane, it comes as a bit of a surprise to find that this South Korean-owned company outranks the Americans.
Based in San Diego, California, Hyundai Translead offers the full range of trailer design options, from flat tops to dry vans, skeletal chassis designs, dollies and refrigerated vans, with an annual production rate of 65,000 trailers.
Hyundai Translead chief sales officer Stuart James and its national account sales deputy general manager Rusty Swarts combined their enthusiasm to showcase the company’s manufacturing centre in California. They did so by using a virtual reality scenario whereby it’s possible to transport your focus into the centre of the manufacturing facility. Having strapped on the appropriate headgear, the viewer can walk through the production lines, watch the assembly process and gain a rapid understanding of the manufacturing systems and sophistication without leaving their seat on the exhibition stand.
The production facility is hugely impressive, with mass production robotic fabrication taking place on an extensive assembly line unlike anything comparable in the Australian market. The investment and quality of the final assembly indicates just what can be achieved with such high production runs.
Centre stage of the company’s exhibit was a prototype of a 53 ft (16.154 metre) refrigerated trailer built from composite panels in a modular construction process. The sandwich moulded-foam wall construction is 63.5 mm thick, instead of the customary 90 mm, but with high density foam it is claimed to achieve the same thermal efficiency. The interior width at floor level is 2473 mm.
The interior of the fridge van features clean wall surfaces without side posts, rivets or roof bows. Thanks to its modular construction, panels can be repaired quickly and easily in the event of damage by cutting out a damaged section, inserting a replacement section and then applying fibreglass over the repair.
But the real story behind the prototype trailer lies in the association between Hyundai Translead and Air Liquide and the application of nitrogen as the means of chilling the load.
As Stuart James explained, the prototype trailer was the first to feature nitrogen as the means to refrigerate the load, with the potential to radically change from the traditional method of using a stationary engine mounted on the front of the van, running on diesel fuel.
“Nitrogen can reduce the interior temperature of the van within 20 minutes from ambient temperatures down to 1.5 degrees Celsius. The nitrogen is stored in a tank underneath the chassis on the prototype version, but in production units it could equally be stored in a series of tanks mounted on the front wall, in place of a traditional diesel-powered fridge unit,” he said.
The advantage to the operator is that air is not recycled around the interior until it can be cooled. The air entering the van interior is already chilled to the required level on entry and if required, staging different evaporators within the cargo area can create different temperature rated environments.
The nitrogen is stored in the external tanks at a temperature of -195 degrees Celsius and piped through to two evaporators mounted on the front of the trailer. Air passes through the evaporators into the interior already chilled, dramatically cutting the time taken by conventional systems, which can be as much as one hour to achieve the desired temperature. No nitrogen actually enters the cargo area, with the gas exhausting to atmosphere, which is comprised 78 percent nitrogen. The system also has the appeal that it basically maintenance free and the carbon footprint of the trailer is reduced by 90 percent, compared with a traditional freezer (reefer) unit.
The use of nitrogen brings into play some cost savings and major benefits in efficiency. Typical costs in the US of refilling the onboard nitrogen tank are around $US100 ($A145), enough for up to a three-day supply. It is then refilled at the operator’s own nitrogen storage facility. The operating costs are estimated at US $3.30 /hour (AUD $4.81/hour).
From a weight factor the nitrogen tank comes in at around the 450 kg mark and when full of gas this increases to 770 kg. This is a major reduction from a typical diesel engine-powered unit that weighs in at around 910 kg and uses fuel from a 190-litre tank at the rate of 3.5-4.0 litres per hour.
A standard diesel-powered fridge engine mounted on a trailer is said to take up to an hour to pull down the interior temperature. The difference in efficiency here being that the air inside the trailer is being recycled and subsequently chilled, rather than entering the trailer already chilled.
Current specifications of the US product range are obviously different from those current in the Australian market, but with the size and ability of the company to adapt to suit our market, that time of entry might already be under closer consideration.
Hyundai Translead has not yet taken steps to export to the Australian market, but with the economies of scale evident from this leading manufacturer in the North American market it certainly has the capability of following some of the smaller players and making significant inroads.