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Home » Refrigerated transport: the lifeline of the distribution cold chain

Refrigerated transport: the lifeline of the distribution cold chain

Compiled by Eamonn Ryan

Refrigerated transport plays a crucial role in ensuring the safe and efficient movement of products from farm, hoof or ocean to fork.

Serco’s new style dry freight interlink trailers boast a higher-than-the-norm loading volume of 141m3 which directly contributes towards lowering transport costs. Image supplied by Serco

Serco’s new style dry freight interlink trailers boast a higher-than-the-norm loading volume of 141m³ which directly contributes towards lowering transport costs. Image supplied by Serco

Refrigerated transport vehicles are a significant investment for businesses. A full-length refrigerated vehicle, including the mechanical horse, refrigerated trailer and refrigeration unit, can cost R3-million or more. These vehicles require constant operation, as downtime for unloading can be costly. Additionally, maintaining the desired temperature, usually as low as -20°C, requires a significant amount of energy, making energy efficiency a major factor.

As the world becomes increasingly environmentally conscious, the refrigerated transport industry is actively adopting sustainable solutions. Refrigeration technologies now focus on minimising carbon emissions and reducing reliance on harmful refrigerants. The use of renewable energy sources, such as solar power, is gaining traction, further reducing the carbon footprint of refrigerated transport operations. Trucks range from small one-ton bakkies to large trailer trucks and can be configured with various systems including engine-drive systems, systems with a separate diesel engine and electric motor (diesel electric), eutectic systems, cryogenic systems and all-electric systems – creating a range to suit any application.

Clinton Holcroft, CEO of Serco. Image supplied by Serco
Clinton Holcroft, CEO of Serco. Image supplied by Serco

Via continuous research and research and development (R&D) in the mechanics, electronics, insulation factors and body work, technology has drastically improved over the years with newer vehicles being able to be fitted with many advanced options compared to what was available in the past.

The key challenges that face today’s refrigerated trailer fleet operators that led to this technology include:

  • Reducing their environmental footprint to comply with evermore stringent requirements from ordering parties Ensuring the distribution of fresh products in densely populated urban areas where access is limited to low- noise, low-emissions vehicles Retaining flexibility needed to operate either distribution or long haul as required when it comes to refrigerated transport, nearly all containers are equipped with an electric-driven unit that is bolted into the container. These units are powered by an electric system, which is used to deliver the container to a trailer. When the container is moved, a diesel generator is attached to the trailer to power the refrigeration system while travelling on the road. Once the container is placed on a ship and connected to the ship’s power supply, it is plugged into a power supply and remains connected to refrigeration throughout its journey.

However, refrigerated transport always carries the risk of product damage. The product can be damaged by either loss of temperature or by allowing the temperature to go too high or too low. For instance, if fresh produce is frozen, it can be damaged. Similarly, if frozen produce is allowed to thaw due to a malfunctioning refrigeration unit, improper airflow, or being loaded at the wrong temperature, it can also be damaged. Cross-contamination is another way in which products can be damaged during transport. For example, if a vehicle that was improperly cleaned after carrying fish is used to transport other products, everything can end up tasting like fish.

Therefore, it’s important for companies that transport perishable goods to have proper maintenance contracts in place for their refrigeration units. This will help ensure that their products are transported safely and efficiently.

Refrigeration systems with maintenance contracts are available for purchase, similar to service contracts for cars. These concepts have been developed over the years and are widely used. Maintenance is always a crucial aspect of refrigeration systems, and it’s important to ensure that they are functioning correctly before transporting perishable goods.

When transporting frozen products in a refrigerated vehicle, it’s essential to pre-trip the system and ensure that it is functioning correctly. The pre-trip inspection is critical to ensure that the temperature is maintained at the required level (at least -20°C). It can be disastrous to discover any issues with the system while on the road – therefore, it’s essential to conduct a pre-trip inspection before embarking on any journey.


E-commerce is driving new shopping trends, but is the product still in a temperature- controlled state at the destination point? Distributors need to be mindful that refrigerated bodies are designed to maintain temperature, so loading at the correct temperatures is critical as well as control of required temperatures during multiple offloads in a round trip.

Clinton Holcroft, CEO of Serco, says: “The pandemic was the trigger to increase consumers ordering for home deliveries in South Africa. This has seen an explosion of motorcycles and scooters taking to the road with various storage box configurations being fitted for transporting groceries and perishable foods.

Protec dryliner with reinforced rear end. Image supplied by Serco
Protec dryliner with reinforced rear end. Image supplied by Serco

“This is where the purpose-built vehicles with multi-temperature capabilities can come into play. Benefits include preventing food spoilage and keeping the integrity of chilled items intact to prolong shelf life and minimise waste and returns. So, if fresh produce retailers are serious about taking advantage of this trend and offering a quality delivery model, they should gear up with the correct delivery setup to ensure maintained quality of the products.”

Holcroft suggests that while it is convenient for short distances and minimal goods, “it is not ideal for maintaining

cold chains as there is no refrigeration or adequate insulation.”

He notes that from a refrigerated body-manufacturer perspective, it hasn’t been easy for customers to differentiate between the thermal performance of one insulated body versus another, but the difference can make a substantial difference over the life of the body in terms of fuel consumed by the fridge, CO2 emissions and maintaining product at the correct temperature..

Holcroft says: “A simple pull-down test can be done, to compare performance between bodies, but this isn’t always possible or convenient for customers to carry out but would give an indication where significant variances exist. We have done our own informal testing and have discovered up to 50% differences in the time it takes to get to temperature and then to maintain temperature.

This has a direct impact on perishable goods, especially when there are multiple deliveries, which is why we have invested in a state-of- the-art PU foam injection process for manufacturing our insulated panels.” One key difference, he says, is that in Europe transporters of perishable foods are required to obtain an ATP certificate which is an independent rating of the body’s thermal compliance to set standards. This is valid for six years and can be extended by a further three years on retesting. “In South Africa there is no such requirement, so being a voluntary process has not seen much support for clear standards to be set and hence performance can vary significantly. When it comes to food, hygiene and the general cold chain management, implementing formal certification for the transport of perishable goods could potentially raise local standards,” says Holcroft.

On the subject of regulation, he adds: “Particularly in urban areas, noise pollution is becoming a growing issue as transporters look to improve efficiencies and distribute at night or early in the morning to avoid peak traffic. Newer equipment is coming out with enhanced features and accessories to minimise noise pollution.”

Serco builds a wide range of truck bodies and trailers to suit transporters’ unique requirements from long distance to short haul to last mile distribution. “We offer single and multi-temperature solutions, and our range covers one-ton bakkie bodies up to 30 pallet trailers.

“Improving thermal performance directly impacts energy efficiency and running costs. New innovations available include using solar panels to power the refrigeration units and tail lifts to reduce environmental impact,” he adds. “In addition, temperature telematic systems are constantly advancing and can effectively identify problems using early warning systems to improve the cold chain.”


Research and development (R&D) plays a crucial role in the evolution of refrigerated transport, and Transfrig (Valeo Thermal Commercial Vehicles South Africa) has the benefit of also having an R&D office in Germany, at Valeo, allowing for greater information sharing.

Transfrig (Valeo Thermal Commercial Vehicles South Africa) has been building transport refrigeration units since 1980. It manufactures directly for the market and deals with the OEMs, end-users, insulated body builders and motor dealers.

Mark Demartinis, MD of Transfrig (Valeo Thermal Commercial Vehicles South Africa) says: “The European market is ahead of the local market in terms of the disruption effected by electrification and the potential for hydrogen-powered vehicles. The road to electrification is far longer in southern Africa than it is in the developed world.

Understanding the pathway or roadmap to electrification is important. Therefore, many people locally are looking for hybrid solutions that can help reduce carbon emissions. Battery-powered solutions and battery power with some solar are among the hybrid solutions available on the market. “From an R&D point of view, it is important to develop robust systems that are designed for the African environment. Reducing diesel consumption is also a priority, both from an emissions point of view and to monitor the price of diesel as it increases. Emission ‘hunting’ on a permanent basis through various forms can help reduce the load on the unit itself and diesel consumption.

Different systems and configurations are available in transport refrigeration. Demartinis describes the two most common types as: direct drive machines driven off a refrigeration compressor mounted on the vehicle’s crankshaft; while more traditional trucks in the distribution centre (DC) environment use diesel-electric refrigeration operations.

In addition, eutectic systems are a smaller, more niche type of refrigeration equipment that are ultimately used by the majority of ice cream distributors in the country – they are required to be charged overnight and generally run with mains power making them on-road emission-free. It pulls the temperature down to roughly -35°C, giving a box temperature of -30°C. It is a good system; however, it is extremely specific to ice cream because of the weight of eutectic tubes in the roof, though it can be modified slightly to the dairy industry.

“A game changer for us is a liquid nitrogen cryogenic system, developed by Cryofridge and operated under licence by Transfrig. It is completely on-road emission-free and has a fast temperature pull-down as it is not governed by the capacity of the refrigeration unit itself. The risk associated with this system is the supply of liquid nitrogen, for which the national infrastructure of bulk nitrogen storage that is required does not yet exist. The investment is substantial and therefore requires a long-term approach to transport refrigeration. I believe this will happen in tandem with the growing need to reduce carbon emissions. In the meantime, it is satisfactory primarily for shorter trips and is already being used. The use of liquid nitrogen is limited by the availability of liquid nitrogen – if someone established bulk depots of liquid nitrogen in key areas such as Bloemfontein it would open up the possibility of long-distance haulage.”

Transfrig has hundreds of these units running at the moment, with a suitable solution existing for 12 to 14 ton refrigerated trucks as well as 15.5m trailers. They carry 450–950ℓ of liquid nitrogen, with the advantage of liquid nitrogen refrigeration being that because there’s no diesel engine, maintenance is far less than that required on a traditional diesel engine machine, explains Demartinis. “Additionally, the integration of some solar power is used to control the fans, as well as the controls on the machine as well as the tailift.”


The company has a service network of 28 independently-owned dealerships throughout the country and SADC region that services and maintains the equipment, as servicing of the refrigeration unit is arguably even more important than for the truck itself. Refrigerated transport maintenance is of necessity a niche market because it is a combination of trades. Servicing is a complex operation due to it having three critical components: diesel mechanical, refrigeration and auto-electrical. “Combining these skills ensures a holistic approach to maintaining and repairing machines. Solving mechanical problems is indeed as critical as addressing refrigerant leaks or electrical issues, given the challenges posed by African roads. And unfortunately, this is a shrinking body of professionals though our service partners are continuously training up skilled technicians.”

1 and 2: SERCO was assigned by Spartan Truck Hire to build three mobile clinics for use by Shout-It- Now in areas where there is little or no access to medical care and attention in South Africa. Images supplied by Serco

There are a couple of training institutions that specialise in refrigeration, such as ACRA and OTTC. Demartinis says there was a curriculum designed for transport refrigeration, but he notes it did not take off as technicians were required to take off an unreasonable three or four months to attend the training, which is not always viable. “Therefore, we provide in-person and online training with our dealers around the country on a monthly basis. This training focuses on sharing intellectual property, discussing upgrades to the equipment, and hearing issues found in the field.”

“For preventive maintenance, it is recommended to service diesel-electric machines every 500 diesel hours (three or four months) of operation, which is a suitable interval for harsh road conditions in Africa. Regular servicing and belt replacements and attention to gas leaks are vital to prolonging the lifespan of these machines.” The manufacture of a refrigerated vehicle is a tailored activity involving a number of parties: the end user, the chassis supplier, the OEM, insulated body bodybuilder and the refrigeration system manufacturer – each of which must understand the specifications and what the customer is looking for.

“We consider maintenance of the fridge and the body as being equally critical as the maintenance of the diesel engine of the truck. Any damage to the insulated body affects the ability to deliver product. Docking is an aspect which requires ongoing education on best practices in transport refrigeration and maintenance. We spend time educating and working with customers to best understand operations and to get the equipment to perform to the customers expectation,” adds Demartinis.

A number of considerations need to be taken into account when manufacturing: how many hours a truck may wait at a DC unloading during which the products have to be refrigerated. It is for this reason that logistics providers still primarily use diesel electric machines – it ensures refrigeration is continuous no matter the circumstances with no risk to products.

He notes that the growth of online shopping has drastically affected the configuration of much equipment in the industry. There is interest in smaller one-ton and even half-ton vehicles looking to be refrigerated; however, refrigerated scooters are not viable at the moment, ultimately because of the mixed load they carry. “Telemetry is critical in the refrigerated transport industry. It is used to monitor the temperature, humidity, and other environmental factors that can affect the quality of the perishable goods being transported. By using telemetry, companies can ensure that their products are being transported in the right conditions, which can help reduce waste and improve customer satisfaction,” says Demartinis.

NextDrive workshop. Image supplied by Cold Link Africa
NextDrive workshop. Image supplied by Cold Link Africa


In the pursuit of sustainable and energy- efficient solutions, the comparison between solar-powered and traditional refrigeration systems has emerged as a topic of substantial interest.

Warren Hurter, co-founder and technical director of solar refrigeration transport business NextDrive, discusses the efficiency of solar-powered refrigeration in contrast to traditional systems powered by diesel motors. “Such systems boast efficiencies exceeding 90%, compared to traditional engines maxing out at around 25%, in addition, the reduction in moving parts contributes to lower maintenance requirements.” He highlights the significance of batteries and inverters. “While the system design is relatively simple – mirroring a residential setup – the challenge with a transportation system lies in intelligently packaging it in a vehicle with its inherent exposure to rough conditions on roads, as well as to enable remote monitoring, and address safety considerations during accidents. The company imports key hardware components, rigorously testing and proofing them through multiple concepts to ensure quality.”

Pietermaritzburg-based trucking company Yacoob’s Transport has added two new Serco-built dry freight interlinks to its refrigerated vehicle fleet. Image supplied by Serco
Pietermaritzburg-based trucking company Yacoob’s Transport has added two new Serco-built dry freight interlinks to its refrigerated vehicle fleet.  Image supplied by Serco

Ensuring the quality of imported components is a critical aspect of their process. Its approach involves conducting multiple proof of concepts and selecting hardware based on factors like durability, longevity and strength. Suppliers, predominantly from Europe, adhere to international automotive standards, with a minimum five-year warranty as a baseline. The environmental benefits of solar- powered refrigeration systems are unequivocal. The elimination of diesel usage drastically reduces carbon emissions, aligning with the global push for greener practices.

As with any technology, solar-powered refrigeration systems have limitations. Battery sizing, rate constraints, and limited roof space for solar panels in smaller trucks are identified challenges. To address these, NextDrive customises designs to minimise damage risks and optimise efficiency. Hurter acknowledges ongoing technological advancements, emphasising the evolution of battery capacity and solar panel efficiency over the past six years. “We started with 250W (and we now use 420W, as this is what fits well on the trucks) though you get up to 600W now.”

NextDrive collaborates with major roleplayers in refrigerated transport – Transfrig, as well as retailers such as ShopRite, which through Transfrig has integrated solar systems into approximately 90% of its fleet. The company manages around 1 600 trailers for ShopRite, each tailored to unique needs, and recently assisted Checkers to roll out its first fully- electric truck. “Solar systems power critical components, showcasing substantial savings, including an annual saving of close to R60-million in diesel costs alone for ShopRite’s fleet,” explains Hurter.

He notes that on average, customers save 4.8ℓ of diesel each day per trailer, with the return on investment for a typical solar logistics investment being 1.4 years from date of installation, based only on diesel savings. Given the extent of potential savings, he believes all refrigerated transport will ultimately go solar-powered unless physically unfeasible. This is an industry still at the commencement of a growth phase. Regarding competition, Hurter acknowledges emerging players in South Africa-based solar logistics, but considers the current landscape a ‘blue ocean’, and one in which they have a long head- start. However, he anticipates increased interest and competition due to growing tax incentives, making their approach more compelling.

The solar incentive is contained in section 12B of the Income Tax Act, being a 125% deductible on business income tax by investing in solar.

This all means that at the moment, the bulk of NextDrive’s work consists of retrofitting. Consequently, the company specialises in augmenting various refrigeration systems, retrofitting solutions to serve as backups and eventually becoming the primary power source. Hurter says successful proof-of-concept trials with Food Lovers Market

and in collaboration with Transfrig, showcasing the effectiveness of solar panels in powering three-phase (diesel-electric-solar) systems off the grid for a week without diesel usage.

Traditional diesel refrigeration systems are primarily being replaced by silent nitrogen refrigeration systems. Hurter adds that these units have an operating life of up to 12 years with significantly reduced maintenance and operating costs.

A solar and heavy-duty lithium battery system has been designed specifically for the needs of Coca- Cola. The system allows for the double column tail lift to operate independently from the horse, with excess solar power available for pallet jack charging and optional security systems. NextDrive’s in-house manufacturing processes involve design of batteries, assembly and handling all wiring components. While not producing specific solar panels, the company manages wiring components and ensures automotive-rated components for reliability in vehicular applications.

The company envisions a future where technology continues to evolve, making solar-powered solutions increasingly viable. NextDrive’s focus remains on expansion, not only within South Africa but also into Africa and potentially Australia. The company sees a promising horizon for growth beyond regional boundaries, especially as the popularity of sustainable solutions continues to rise.


Thermo King has recently entered a long-term supply agreement with ZF Commercial Vehicle Solutions, a systems supplier to the road transportation industry. As a result of the agreement, Thermo King will combine its expertise in transport refrigeration with ZF’s trailer system data to offer a comprehensive telematics solution covering the complete refrigerated trailer data within one platform.

“By partnering with market leaders and experts in their fields, Thermo King creates unique value propositions for our customers,” said Isil Dedeoglu, vice-president for services and aftermarket at Thermo King Europe, Middle East and Africa (EMEA). “The collaboration with a key industry player like ZF will allow Thermo King to become a one-stop solution provider for customers looking to maximise their operational efficiency by digitising their trailer fleet. This co-operation will give our customers even easier and deeper insight into their fleets and the information they need to further improve their uptime and reliability.”

Hino 500 1627.Image supplied by Serco
Hino 500 1627.Image supplied by Serco

Hjalmar Van Raemdonck, Head of Digital Systems Solutions with ZF’s Commercial Vehicle Solutions division, says: “We are delighted, Thermo King is using ZF technology to further strengthen its offerings to  its customers. For ZF, trusted industry
collaborations, including the one with Thermo King, help create unique scalable value for a broader range of customers and are essential to ZF’s strategy with regards to SCALAR, our fleet orchestration platform.”

The new offering will enable customers to remotely monitor both refrigerated and dry fleets operating Thermo King refrigeration units and access all integrated trailer data through the Thermo King TracKing platform.

Thermo King will use ZF’s new SCALAR Fleet Orchestration Platform, throughout its trailer telematic solutions, to import data from ZF and all other makes of trailer-EBS systems and tyre pressure monitoring systems (TPMS). This new feature will allow Thermo King TracKing customers to leverage multi-brand EBS, odometer, axle-load and TPMS data and further optimise their trailers’ uptime, maintenance and fuel efficiency. With easy access to comprehensive information about the status of their refrigerated trailers via TracKing, customers will be able to act and react to operate more efficiently, avoid unscheduled downtime, reduce fuel consumption and create more sustainable transport. This new digital solution will also support fleets in complying with the Regulation No. 141 of the Economic Commission for Europe of the United Nations (UN/ECE), which requires all new registered trailers to be equipped with TPMS from July 2024.