The bulk of high-value perishable food product is delivered to market in transport refrigeration units (TRUs), which are rigid, thermally insulated boxes equipped with a cold energy supply system, commonly an auxiliary diesel engine coupled to a compressor unit. There are over 4 million diesel powered transport refrigeration units in operation worldwide. Each one consumes 2,600 gallons of fuel and emits 32 tonnes of greenhouse gases (GHG) and particulate matter annually. Industry analysts expect the number of units to exceed 9 million by 2025.
The operational demands on transport refrigeration systems, which are a central feature of the cold chain, are much more severe than for any other refrigeration system. The equipment must operate in variable climactic conditions and harsh operating environments, while carrying diverse loads of high value perishable goods that must reach their destination without any loss of quality. This is simply unattainable in many regions of the world and creates food safety and security issues that are leading to significant post production food wastage.
According to the UN Food and Agriculture Organization, global food wastage, caused in part by weak links in the cold chain, exceeds 1.3 billion tonnes annually. That is equal to USD$2.5 trillion or 30% of total production annually. In some countries that figure exceeds 40%. Meanwhile 17% of the world’s population live at near-starvation levels. Current estimates have the global population increasing to over 9 billion by 2050 with much of the growth occurring in developing countries. Increasing food production to meet that demand, using present production and transport techniques, will have profoundly negative consequences on the environment. Producing more food is not the solution to the looming food security crisis. Reducing food wastage is!
Nothing preserves food quality and value retention as effectively as refrigeration. Natural refrigerants have been in use for over 200 years, but the return to natural refrigerants by the cold chain industry has only recently begun. Carbon dioxide (CO2) is the one natural refrigerant that has found broad favour across that industry.
Carbon dioxide is a natural, non-toxic, non-flammable substance with an ozone depletion potential of zero and a global warming potential (GWP) of 1. Synthetic refrigerant GWPs range from 675 to 14,000. CO2 can be easily recovered from industrial gas emissions for use as a natural refrigerant, thereby relieving the cold chain industry’s dependence on synthetic refrigerants and fossil fuels. It is a simple solution to a complex problem.