Hot and cold

Blowing hot and cold (Day 235)

Hot and coldChemical engineers are responsible for much the world’s economic output in the form of goods and services consumed by industry and consumers.

In numbers, the world’s Gross Domestic Product (GDP) looks something like this: £48,000,000,000,000 (US$75,000,000,000,000).

From a chemical engineering perspective, once those goods have left the factory gate or disappeared down a pipe, there might be a tendency to forget the enormous skill and energy to get these products to market – in the right condition.

The challenge is particularly acute for the distribution of food in countries with large and growing populations and has been highlighted recently by the University of Birmingham in the UK.

They estimate that £4.4 billion (US$6.7 billion) of fruit and vegetables in India is wasted annually during the distribution process. They suggest all this waste could be eliminated with investment into a sustainable cold chain of refrigerated warehousing and transport.

The problem is not just confined to food.

India is the world’s third largest pharmaceutical producer and estimates suggest almost 20 per cent of temperature sensitive healthcare products arrive damaged or degraded because of a broken cold chain, including 25 per cent of vaccines.

refrigerated trailerPutting investment to one side there’s also an environmental aspect to consider.

For example, the diesel-powered transport refrigeration unit (TRU), the workhorse of the global cold chain, consumes up to 20 per cent of the truck’s fuel, but also emits 29 times as much particulate matter (PM) and six times as much nitrogen oxide (NOx) as a modern propulsion engine.

The good news is that the University of Birmingham is developing radically new technological solutions for cold storage and utilisation.

Their work includes novel cold storage materials and manufacture technologies that are easier to use, more cost effective and deliver a better performance. Much of this work is undertaken by the Birmingham Energy Institute (BEI) at the University.

One solution to this problem is to use the vast amounts of cold lost to the environment, especially during the regasification of liquefied natural gas (LNG).

LNG is natural gas ‘packaged’ in cold, which is then thrown away when the gas is ‘unpacked’. This cold can be recycled to produce cheap, low-carbon liquid air and provide zero-emission cooling and power in a wide range of static and mobile applications.

Liquid air can also be produced from ‘wrong time’ renewable energy, such as surplus wind power produced at night when demand is low.

Liquid nitrogen, which can be used in the same way as liquid air, is already widely available in India and the industry has 3,500 tonnes per day of spare production capacity.

This would be enough in principle to cool some 17,000 refrigerated vehicles, twice the size of India’s current refrigerated truck fleet, and equal to the estimated immediate unmet demand.

In 2015, the BEI will lead a ‘Commission on Cold’ to investigate solutions to deliver sustainable cooling and power and you can find out more about the University of Birmingham’s work in this field in their report called The prospects for liquid
air cold chains in India.

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