Refrigerated transport is a way of transporting goods in specially designed, temperature-controlled vehicles.

Perishable goods such as food, pharmaceuticals, flowers and medical products transported in vans, lorries and trailers, are required to be kept at a certain temperature to prevent them from deteriorating and losing value.

Equipment installed to these vehicles to control the temperature are called transport refrigeration systems. Their function is to remove unwanted heat from the storage area to maintain a set temperature. For some frozen products this could be as low as -25 to -30 degrees centigrade.

Known as TRUs, Transport Refrigeration Units are climate-controlled containers that keep the cargo at a regulated temperature, whether the truck engine is running or not. Traditionally, most TRUs have been diesel-powered but due to air quality concerns and the green agenda, hybrid and electric options such as FRIGOBLOCK are growing in popularity.

In a standard refrigeration system, the aim is to remove heat from the air in the space surrounding the stored product and then release it outside of the storage space. This is achieved by causing a liquid refrigerant to change state from a liquid to a gas within the storage space, and thereby absorbing heat from the air in the space during this process.

The absorbed heat is then carried within the gas to the outside of the storage space, where it is condensed back to a liquid and in the process gives up its heat to the atmosphere. This cycle is repeated continuously to achieve the desired temperature within the storage space.

Most transport refrigeration systems are used for the carriage of frozen or chilled food and beverage products. An important feature of most transport refrigeration systems is the ability to operate at a range of temperature levels for certain products. See the most conventional temperature ranges below.

Different products demand different temperatures while in transit. An optimal transport temperature is product-specific calling for a wide variety of temperature settings, but five temperature standards are among the most common:

• Deep freeze: -25C to -30C is the coldest temperature range that most conventional refrigerated units can maintain – usually for seafood and ice cream.
• Frozen: -10C to -20C – used for frozen meat and bakery products.
• Chilled: 2C to 4C – the standard temperature for refrigerated transport – used for fruit, veg and fresh meat.
• Pharmaceutical: 2C to 8C.
• Banana: (12C to 14C) Believe it or not, as one the world’s most produced fruit, the banana has its very own temperature setting to control ripening during shipping. Other tropical fruits are best transported in this range too.

In order to keep machinery working as efficiently as possible regular maintenance is very important. The cargo carried in refrigerated vehicles is often very high value and it is crucial to ensure the equipment is working correctly to protect the product on board.

A transport refrigeration engineer will install and commission systems on vehicles and trailers, provide regular servicing and respond to breakdowns. It’s an important role in keeping the country’s supply moving.