Inside the Dearman zero-emission transport refrigeration system – Nick Owen

2017-05-22T16:47:30+00:00April 28th, 2015|Viewpoints|

Transport refrigeration is a technology that we all rely on. The perishables we buy in supermarkets – meat, fish, dairy, fruit and vegetables – are all kept fresh by fleets of refrigerated trucks. Without these trucks, not only food but also medicines and vaccines that need to be kept cold would perish.

Demand for refrigerated transport is also rising rapidly. More food and more medicine is being kept cold, and is reaching more people around the world, because there are more chilled trucks on the road. That’s a good thing. But the problem is – keeping things cool can be very polluting.

Diesel powered, transport refrigeration units, which keep refrigerated trucks cold, are poorly regulated and disproportionately dirty. In fact, diesel refrigeration units emit up to 29 times the particulate matter and six times the NOx of a modern Euro 6 truck engine.

But Dearman is bringing a ‘clean cold’ zero-emission alternative to market. The innovative Dearman transport refrigeration system is powered by liquid nitrogen, but how does the system work?

Liquid nitrogen is pumped through a heat exchanger inside the truck, where it acts like a heat sink, cooling the compartment down. The nitrogen – now a gas, but still quite cold – is fed into the Dearman engine where it mixes with warm water and expands rapidly, generating power. This power is used to drive a conventional refrigeration cycle, which cools the compartment further.

The Dearman refrigeration system uses the liquid nitrogen to generate both electrical power and further cooling, meaning it is far more efficient than systems that use the nitrogen for cooling on its own.

What’s exciting about the Dearman system is that it’s zero-emission – the only thing coming out of the exhaust is cold nitrogen, which is simply absorbed back into the atmosphere.

Dearman’s transport refrigeration system is also not only cleaner than current technology, but it will also be cheaper, offering payback in around a year. It’s an economically and environmentally viable technology, benefiting both operators, the environment, and ultimately you and me.

The Dearman system went into on-vehicle trials a few weeks ago. The first data sets are encouraging and it is performing well. We are making rapid progress in making this revolutionary clean cold technology a reality.

If in the coming decades there are going to be millions more refrigerated trucks on the road, supporting the growing global population and ensuring that less food gets wasted, it’s vitally important that we make them as sustainable as possible. Dearman is engineering technology to achieve that goal.