Reefer Truck

A reefer truck, or refrigerated truck, is a type of vehicle specifically engineered and equipped to transport perishable goods that need to be kept at specific temperatures during transit. The central feature of a reefer truck is its built-in refrigeration system, which can cool down or maintain the cargo space at temperatures ranging from freezing to moderately cool, depending on the requirements of the products being transported.

Reefer trucks are highly insulated to prevent heat exchange between the interior of the truck and the external environment. This insulation ensures that once the desired temperature is achieved within the cargo area, it can be maintained with minimal energy consumption.

Reefer trucks come in various sizes, from large 53-foot trailers pulled by semitrucks, to small vans used for local deliveries. Larger reefer trucks may have the ability to create different temperature zones in different sections of the truck. This allows transportation of multiple types of goods requiring different temperature settings in one trip.

The refrigeration unit on these trucks is typically powered by a separate small diesel engine, although some newer models may use electric refrigeration systems. The refrigeration unit works by removing heat from the interior of the truck and releasing it outside. This is done through a process of evaporation and condensation using a refrigerant.

Reefer trucks are used to transport a variety of products, including fresh and frozen foods, flowers, pharmaceutical products, and any other goods that require a specific temperature range to maintain their quality.

Key takeaways

  • Definition: Reefer trucks are specialized vehicles equipped with refrigeration units to transport perishable goods at controlled temperatures.
  • How it works: The refrigeration unit, often diesel-powered, circulates a refrigerant through a cycle of compression, condensation, expansion, and evaporation to maintain set temperatures.
  • Types: Single-temp, Multi-temp, Cryogenic cooling, Hybrid, and Built-in reefer trucks exist, catering to different transportation needs.
  • Pros and cons: Pros include transport variety, long-distance shipping, business opportunities, and reduced spoilage. Cons are higher costs, increased maintenance, limited load flexibility, and environmental impact.
  • Explore your options: Career opportunities and load boards specific to reefer trucking are available through companies like Roehl, and platforms like Truckstop.

 

How it works

The basic principle behind refrigeration is the removal of heat from an enclosed space to lower and maintain the space's temperature at the desired level. 

The main component of a reefer truck is the refrigeration unit, which is typically located at the front of the trailer. A refrigeration unit is essentially a small diesel engine that operates a compressor, although electric and hybrid options are becoming increasingly common. The compressor circulates refrigerant through a system of condenser coils and evaporator coils.

Refrigeration involves the following steps:

  1. Compression: The refrigeration unit's compressor pressurizes the refrigerant, which raises its temperature. At this point, the refrigerant is in a gaseous state and is hotter than the temperature outside the truck.
  2. Condensation: The hot pressurized refrigerant flows through the condenser coils located outside the insulated cargo area. As the outside air flows over the condenser coils, the refrigerant cools down and condenses into a high-pressure liquid.
  3. Expansion: This high-pressure liquid refrigerant then moves through an expansion valve, where it rapidly expands and cools, becoming a low-temperature, low-pressure gas.
  4. Evaporation: The cold, low-pressure refrigerant then travels through the evaporator coils inside the cargo area. As it evaporates and returns to a gaseous state, it absorbs heat from the cargo area, thereby cooling it down. A fan blows air over the coils and circulates the cooled air throughout the cargo area to maintain a consistent temperature.

This cycle repeats continuously to maintain the set temperature inside the cargo area.

The cargo area of a reefer truck is heavily insulated to minimize the transfer of heat between the outside and the inside. The doors are also well-sealed to prevent warm air from entering when the doors are closed. Modern reefer trucks often include a thermostat and a control unit. 

The control unit allows the driver or operator to set the desired temperature, and the thermostat monitors the temperature inside the cargo area. If the temperature begins to rise above the set level, the control unit activates the refrigeration unit to cool the space back down.

Some advanced reefer units also come with multi-zone cooling capabilities, allowing different sections of the cargo area to be set to different temperatures. This is useful for transporting a variety of goods that each have their own specific temperature requirements. Some reefer trucks also have a standby mode, which allows the refrigeration unit to be powered by electricity when the truck is parked, saving fuel and reducing emissions.

Reefer fuel

Reefer fuel is a crucial component in operating refrigerated trucks, or reefer trucks. While the truck itself runs on diesel fuel, the refrigeration unit has its own separate fuel tank, also typically filled with diesel. This separate fuel source allows the refrigeration unit to operate independently of the truck's engine, providing constant temperature control for the cargo area, regardless of whether the truck is moving or parked.

The reefer fuel powers the compressor in the refrigeration unit, which circulates the refrigerant and removes heat from the cargo area. The use of separate reefer fuel ensures that the refrigeration unit can continue to function and maintain the temperature inside the truck, even when the main engine is turned off during stops or breaks, thus protecting temperature-sensitive goods from spoilage.

Given the importance of maintaining the correct temperature for perishable goods, it's crucial for drivers to ensure the reefer fuel tank is adequately filled. Failure to do so can cause the refrigeration unit to shut down, potentially damaging the goods being transported.

Moreover, the consumption of reefer fuel varies depending on several factors, including the outside temperature, the set temperature inside the cargo area, the condition of the insulation, and the frequency of door openings. With the advent of environmental concerns and advancements in technology, some newer reefer units also offer electric standby capabilities, which can switch the power source from reefer fuel to electricity when the truck is parked, reducing emissions and potentially saving on fuel costs.

Reefer trucks types

Single-temp units

These are the most common type of reefer trucks, and they are designed to maintain a single, consistent temperature throughout the entire cargo area. They are best suited for shipments that consist of a large quantity of the same type of product, such as frozen foods or fresh produce, that all require the same temperature control.

Multi-temp units

These reefer trucks are designed with multiple compartments, each of which can maintain a different temperature. This allows for the simultaneous transport of different types of goods that require different temperature controls. For example, a multi-temp unit could transport frozen meat in one compartment, fresh vegetables in another, and dairy products in yet another, each with their optimal temperatures.

Cryogenic cooling trucks

These are a specialized type of reefer truck designed for extremely temperature-sensitive goods. They use liquid carbon dioxide or liquid nitrogen in a cryogenic system to quickly cool down the cargo area to very low temperatures, sometimes well below freezing. Cryogenic trucks are often used in medical and scientific fields for items such as organs, biological samples, or certain pharmaceuticals.

Hybrid reefer trucks

These are a more recent addition to the variety of reefer trucks available. Hybrid reefer trucks use electric or hybrid power systems to run the refrigeration units. This offers significant fuel savings and reduces carbon emissions, making them a more environmentally friendly option. They can operate in electric mode when driving in urban areas or when parked, reducing noise and air pollution.

Built-in reefer trucks

These trucks have the refrigeration unit built directly into the truck body, rather than being a separate attached trailer. They are typically smaller than trailer-based units and are often used for local deliveries in urban areas where maneuverability is crucial. They are commonly seen in use by grocery stores and food service companies for the delivery of fresh or frozen goods.

Trailer reefer trucks: 

These are large semi trucks with a separate, detachable refrigerated trailer. They are used for long-haul transport of temperature-sensitive goods and can carry a large volume of products. Essentially the backbone of the cold supply chain, they enable the distribution of perishable goods across vast distances.

Pros and cons

Pros

  • Transport variety: Reefer trucks enable the transport of a wide variety of perishable goods, from food items to medical supplies. This allows companies to expand their product range and serve a wider market.
  • Long-distance shipping: By controlling the temperature inside the truck, perishable goods can be transported over long distances without losing their quality. This feature is particularly important for global supply chains.
  • Business opportunities: Because they can transport a wider range of products, reefer trucks can open up new business opportunities for trucking companies, including contracts with businesses in the food service and medical industries.
  • Reduced spoilage: Reefer trucks drastically reduce the chance of goods getting spoiled during transportation. This minimizes losses and increases the overall efficiency of the supply chain.

Cons 

  • Higher costs: Reefer trucks are more expensive to purchase and operate compared to standard trucks. They require more fuel and more maintenance due to their complex refrigeration systems.
  • Increased maintenance: The refrigeration unit in reefer trucks requires regular maintenance and inspections, adding to their operational cost and complexity.
  • Limited load: Goods in reefer trucks need to be loaded and unloaded more quickly than in standard trucks to minimize exposure to outside temperatures. This can limit their flexibility and increase the complexity of logistics planning.
  • Environmental impact: Reefer trucks, especially those using older technology, can have a higher environmental impact due to increased fuel consumption and the use of refrigerants. Hybrid or electric reefer trucks are being developed to mitigate this issue, but they currently have a higher upfront cost.

Explore your options

Now that you've delved into the world of reefer trucks, perhaps you’re considering a career in driving these specialized vehicles. If so, our partners at Roehl are leading carriers in the industry, offering excellent opportunities for driving jobs in the reefer truck segment. They have a strong reputation for both the quality of their service and dedication to their drivers, providing excellent work conditions and competitive compensation.

If you're a driver or owner-operator of a reefer truck seeking to maximize your load and route efficiency, our partner Truckstop offers robust load boards specifically tailored for reefer trucks. Leveraging their services can help you optimize your operations, find lucrative loads, and build a successful, sustainable career in the reefer truck industry. 

By partnering with these industry leaders, you can take full advantage of their expertise, resources, and networks, propelling your reefer truck journey forward.

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