As you might know, automobile refrigerated trucks are designed for transporting goods that require a specific temperature range. These goods include food products, medicines, flowers, and more. For example, vegetables need a microclimate around +18°C, fresh meat requires temperatures from -1°C to +1°C, and frozen fish needs temperatures ranging from -20°C to -25°C.
For this reason, some refrigerated trucks have their interior divided by fixed or removable partitions, allowing the transport of different products in one unit while maintaining the required temperature in each compartment. These are the so-called multi-temperature refrigerators, which utilize specialized refrigeration units.
What Are They Made Of?
The body of a refrigerated truck is typically constructed from special isothermal sandwich panels designed to maintain the desired temperature inside the van. These panels are most commonly made from polyurethane foam, which boasts a low thermal conductivity of 0.035 W/m² at a density of 60 kg/m2. The panel thickness ranges from 40 to 80 mm, with the joints between panels carefully sealed to prevent unwanted heat loss.
The exterior of the isothermal body is lined with stainless steel or aluminum, while the interior can be lined with aluminum, steel, laminated plywood, special plastic, or other materials.
The floor of the body is also made of polyurethane sandwich panels, with an additional top layer of metal or plywood sheets, or polymer panels. The best material for doors is an aluminum sheet with an insulating layer of plywood or porous plastic.
An air gap around the cargo is crucial to prevent contact with the body lining. To facilitate this, plank walkways about 2.5 cm high are installed on the floor, with grooves in the side walls. It’s very important that the body structure does not have metal parts connecting the outer and inner linings, as these can create thermal bridges that reduce insulation effectiveness. For the same purpose—to prevent cold air from leaking out—the end surfaces of the doors and doorways are given a beveled or conical shape. High-quality rubber gaskets are also used between these surfaces.
Refrigeration Equipment
Different refrigerator models come equipped with refrigeration systems capable of maintaining temperatures inside the body from as low as -20°C to as extreme as -38°C. Notably, some models also double as heating units, capable of maintaining temperatures up to +12°C even when the outside air temperature drops to -20°C. These features make them particularly useful during the cold season and in northern regions for transporting canned goods, drinks, and more.
Most refrigeration equipment in these units is powered by an autonomous internal combustion engine, typically installed on the vehicle or trailer/semi-trailer. This setup is particularly effective for heavy-duty vehicles. For light delivery vehicles, refrigeration units are usually powered by the main engine.
Additionally, refrigerated vehicles equipped with eutectic plates can also be used. These plates are filled with antifreeze and frozen in a special freezer to -30°C at the vehicle fleet’s premises. Once installed in the vehicle’s van, they can reliably maintain this temperature for up to 12 hours, making them ideal for tasks that involve frequent door openings, such as ice cream deliveries within a populated area. In a conventional refrigerated van, the required temperature level is maintained by circulating a refrigerant, typically freon, within a closed circuit inside the cooling unit.
It’s important to note that these refrigeration units can be positioned in different ways on the vehicle. Firstly, they can be mounted above the driver’s cabin, maximizing the body’s capacity. Secondly, they can be placed directly inside the van, which reduces its usable capacity. Lastly, a separate arrangement is possible, where the unit’s condenser is placed outside the body and the evaporator inside the van. For refrigerated units on trailers or semi-trailers, the refrigeration systems are usually installed outside the vehicle, often on the front wall.
New Solutions
Refrigerator manufacturers are constantly innovating to enhance design, efficiency, and environmental friendliness. The European leader in trailer equipment production, Schmitz Cargobull, stands out in the market by producing refrigerators with an in-house refrigeration unit, rather than sourcing it externally. This new-generation unit features a Common Rail diesel engine that boasts a 10% reduction in fuel consumption.
However, Schmitz Cargobull has introduced an even more impressive innovation: the Schmitz S.KOe 600L refrigerated semi-trailer. Unlike other equipment of this type, it is a fully electric model featuring a cutting-edge cooling unit with built-in power electronics, a battery system, and an axial generator—all without producing harmful emissions. Additionally, the cooling unit operates very quietly, making it ideal for urban use during early mornings, late evenings, and at night. Remarkably, it is designed for both cooling and heating the transported goods, with a maximum cooling power of 15,800 W and a heating power of 10,500 W.
On this refrigerated semi-trailer’s chassis, batteries and a special compartment for 36 pallets replace the traditional fuel tank. Despite these modifications, the load capacity remains nearly identical to its diesel counterparts.
Energy recovery occurs during braking and upon reaching certain speeds, extending the refrigerator’s operating time without recharging or reducing the mains’ recharging time.
It’s important to note that this electric refrigerator is fully integrated into the Schmitz Cargobull telematics system, enabling users to access critical data such as battery charge level, remaining range, real-time charging information, and more through the Schmitz Cargobull telematics portal.
Recently, renowned refrigeration unit manufacturer Thermo King unveiled the Advancer model, a groundbreaking product in its lineup. The main distinction of this model lies in its fully variable, high-powered airflow, independent of engine speed. This feature ensures the fastest pulldown and, most importantly, offers the lowest fuel consumption on the market.
For the first time, a 48 V operating voltage system has been implemented on refrigerators. This new, low-voltage motor-generator is known for its economical operation and reliability. This model features new and additional sensors that display information in the proprietary TracKing system, covering fuel consumption, theft alerts, battery charge level, and more. Importantly, it also offers remote temperature control capabilities.Explore a wide selection of refrigerated trucks for cargo transportation on the Autoline website. Our convenient filters will help you choose the most optimal brand and model for your needs.