Posted: May 23, 2025
Transport refrigeration systems in refrigerated trucks and reefer vans, play a crucial role in transporting perishable goods. These vehicles are equipped with specialized refrigeration units, insulation and digital thermostats that maintain a consistent temperature, ensuring that items like food, pharmaceuticals, and other temperature-sensitive products remain fresh during transit. Understanding how these systems work can provide valuable insights into their importance in the cold chain.
The Basics of Refrigeration
At its core, refrigeration is a process that removes heat from a designated area to lower its temperature. In mobile reefer vans, this is achieved through a refrigeration cycle that involves four main components: the compressor, condenser, expansion valve, and evaporator.
Compressor:
The cycle begins with the compressor, which is responsible for compressing the refrigerant gas. This gas is typically a chemical compound that can easily change from a gas to a liquid and back again. R-134a refrigerant for fresh set points and R-452A for frozen and multi-temp applications is now the standard refrigerant for truck and trailer units like Thermo King due to its lower Global Warming Potential than some older refrigerants. When the gas is compressed, its pressure and temperature increase.
Condenser:
The high-pressure gas then flows into the condenser, where it releases heat to the outside environment. As it cools down, the gas condenses into a liquid. This process is facilitated by the condenser coils, which are usually located on the exterior of the van.
Expansion Valve:
The liquid refrigerant then passes through an expansion valve, where it experiences a drop in pressure. This sudden decrease in pressure causes the refrigerant to cool rapidly and partially evaporate, turning it into a low-pressure mixture of liquid and gas.
Evaporator:
Finally, the low-pressure refrigerant enters the evaporator, which is located inside the van. Here, it absorbs heat from the interior of the van, causing the refrigerant to evaporate completely back into a gas. This heat absorption cools the air inside the van, maintaining the desired temperature for the goods being transported.
Temperature Control
One of the key features of mobile refrigeration systems is their ability to maintain specific temperature ranges. Many refrigerated vans are equipped with digital thermostats that allow drivers to set and monitor the internal temperature. This is particularly important for transporting temperature sensitive items like vaccines, which require strict temperature control to remain effective.
Power Sources
Refrigerated vans can operate using different power sources. Some are equipped with direct-drive, diesel or electric-powered refrigeration units, while others may use a combination of both. A direct drive refrigeration unit uses the vehicle’s engine to power the compressor, eliminating the need for a separate power source. A diesel drive refrigeration unit uses a built-in diesel engine to power the compressor, ensuring reliable cooling for perishable goods even when parked. Electric units are often preferred for urban deliveries, as they can run on the vehicles 12V power supply or be plugged into a power source when parked, reducing fuel consumption and emissions.
Insulation and Airflow
To enhance the efficiency of the refrigeration system, mobile vans are designed with high-quality insulation. This insulation minimizes heat transfer from the outside environment, helping to maintain the internal temperature. Additionally, proper airflow is essential for effective cooling. Many refrigerated vans are equipped with air chutes and fans that ensure cold air circulates evenly throughout the cargo area, preventing hot spots that could compromise the integrity of the goods.
Portable Refrigeration Alternative
Dedicated refrigerated vans are designed specifically for temperature-sensitive cargo, providing a built-in cooling system that maintains a consistent environment. However, they can be costly and may not always be necessary for smaller loads. Portable refrigeration units like Coldtainer offer flexibility and precise temperature management, making them ideal for varying shipment sizes. Utilizing the same commercial grade refrigeration system, thermostat and insulation in a portable rugged design, they ensure durability in tough conditions, allowing businesses to maintain the cold chain without the need for a dedicated vehicle. This versatility can lead to significant cost savings and increased efficiency than traditional refrigerated van solutions.
The refrigeration system in a reefer truck is a sophisticated mechanism that plays a vital role in the transportation of perishable goods. By understanding how these systems work, we can appreciate their importance in ensuring that products remain safe and fresh from the point of origin to the final destination. As technology continues to advance, we can expect even more efficient and environmentally friendly refrigeration solutions in the future. Thermo King Eastern Canada is an authorized Thermo King and Coldtainer sales, service, and parts dealer with a background deeply embedded in transport temperature control. If you have any questions regarding refrigeration systems for mobile vans, contact Thermo King Eastern Canada with 7 branch locations across eastern Canada to serve you.