AFCCC, Featured

Effectiveness of Refrigeration Power

effectiveness of refrigeration power

The Forgotten Feature of Thermal Efficiency, the effectiveness of refrigeration power is dicussed by Mark Mitchell, Chairman, Australian Food Cold Chain Council (AFCCC).

In the world of truck and trailer refrigerated body benchmarking, a lot of time is spent worrying about the K value or ‘Coefficient of Insulative Effectiveness’. This is of course, important, as is any measurement or standard that confirms the thermal quality of a transport asset.

The diagram below explains it well. If a body is built properly using the highest quality materials and techniques, the K value is lower, and the body will reject more of the outside heat from entering the refrigerated space.

This is all great, but all too often the second part is forgotten, which is the effectiveness of the refrigeration system in combination with the quality of the refrigerated body to achieve an efficient outcome.

The refrigeration system must have enough capacity to overcome the heat leakage of the trailer or truck body and the additional heat load imposed from such things as infiltration, product load, deterioration of the insulation material, and equipment load such from fans and lights. 

All the good work of building a great trailer body can go out the window with the wrong choice of refrigeration, and conversely the work of a good refrigeration system could all be in vain if connected to a thermally inefficient or faulty body. 

A struggling refrigeration system means that the system needs to continuously operate to cope with the heat load, which results in significantly higher power and fuel consumption. Additionally, temperature sensitive goods such as dairy and meat could be affected and wasted in the absence of proper performance. 

In addition to testing for airtightness and heat leakage, the Australian Standard AS4982 sets out requirements of refrigeration performance by measuring the time taken to reduce the temperature in a body, and the system’s ability to hold this temperature over time. For a body to achieve a freezer classification (Class C), the system must start at 38°C and reach -18°C within eight hours and hold this temperature for an additional four hours with an additional heat load of 35 percent added. 

effectiveness of refrigeration power
Effectiveness of refrigeration power

This requirement establishes the very important partnership between the refrigeration system and the body of the vehicle. It is the only true way of determining if a truck body or refrigerated trailer is fit for the purpose and the temperature requirement it is built for.

Effectiveness of refrigeration power

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