What is a Reefer Trailer? - AllCarIndex

What is a Reefer Trailer?

May 03, 2023

Humans are now able to get all the fruits and vegetables from around the world in their nearby supermarkets. What makes this possible is the advent of high-power refrigerators that store these perishables and keep them fresh. 

However, it's not just the refrigerators that help bring food items from various places to the local market. Reefer trailers are an essential part of this process as they help in the transportation of these goods. 

These vehicles are equipped with devices that keep the temperature seeled inside the truck so that the perishable items do not spoil and retain their freshness. But what is a reefer trailer? Let's find out!

What is a Reefer Trailer?

Reefer trailers are refrigerated trucks that carry or move any type of reefer freight. These are usually perishable items such as vegetables, fruits, meat, dairy, and chemicals. 

It is a highly insulated, securely sealed container with a Trailer Refrigeration Unit (TRU) installed on the exterior of the front wall. It helps regulate the temperature inside the trailer and keeps the goods in their original condition.

It is not used to raise or lower the temperature when transporting goods. Instead, maintaining the freight's temperature while it is being loaded is the primary job of a reefer trailer. 

The quality and shelf life of the cargo being transported is maintained and extended by controlling the temperature in the trailer.

How Does a Reefer Trailer Work?

With a small diesel engine and a refrigeration compressor, the Trailer Refrigeration Unit (TRU) is a self-contained refrigeration system equipped in the trailer. 

This device cycles as necessary to maintain the initial temperature in the trailer. A tiny engine drives the compressor, drawing in and compressing the gaseous refrigerant to liquefy and release heat from it.

The condenser takes the liquid from the compressor for heat exchange and fills the tube all the way to the connected fins. These fins cool the outside air that passes through the condenser. 

The well-insulated insides of the reefer ensure that the temperatures remain the same throughout the journey as these processes keep going.

Features of a Reefer Trailer

Reefer trailers come in a variety of sizes and capacities. However, their components remain more or less the same. Here are some of the features of a reefer trailer.

Dimensional and Capacity

- Reefer trailers are generally 48 to 53 feet in length and 8 feet and 1.5 inches wide from the inside.

- A standard reefer trailer height is around 13 feet 6 inches with 8 feet 7 inches internal height.

- A reefer can weigh anywhere between 12,455 pounds to 14,455 pounds. The maximum weight can be up to 65,000 pounds, with a maximum load capacity of 55,000 pounds for a standard reefer trailer.


- A compressor converts the gaseous refrigerant and compresses it to a cool fluid that enters the system as the hot gas leaves.

- A condenser cools the compressed gas with the help of a fan-based cooling system. The pressure within the condenser causes the gas to condense and liquidize. This leaves a high-pressure, normal-temperature liquid behind.

- The expansion valve controls how much refrigerant flows across the whole system. However, the molecules of the refrigerant expand when the valve limits the flow, creating a cold low-pressure liquid.

- The evaporator in the reefer converts the cold, low-pressure liquid into a low-pressure, low-temperature gas. Drawing air from the cargo compartment at room temperature and directing it over the evaporator coils and fins allows the air to move freely throughout the trailer.

- Reefers also ensure proper air circulation throughout the trailer with the help of air delivery chutes or metal channels.

- Foam insulation and airtight doors, along with insulated walls of the trailers, maintained the temperature inside throughout the entire trip.


Reefer trailers help in the transportation of perishable goods to and from various places, keeping them fresh all the way. These trailers are well-insulated, which keeps the temperature under control. This prevents the spoiling of perishable items, helping with their easy transportation.