‘Clean cold’ technologies breakthrough at motor industry awards

26 November 2014

The urgent need to develop sustainable transport refrigeration systems has been recognised for the first time by a prestigious motor industry competition. Two of the six companies on the shortlist of the 2014 SMMT Award for Automotive Innovation announced last night are developing innovative cooling technologies to reduce the impact of the highly polluting secondary diesel engines used on most refrigerated trucks today. With investment in cold logistics booming around the world, it is a timely recognition of the inevitable damage to the environment and human health if the exponential growth in diesel refrigeration goes unchecked, and of the arrival of a potentially £multi-billion market in ‘clean cold’ technologies.

The diesel powered Transport Refrigeration Unit (TRU) is the trucking industry’s big challenge. While truck propulsion engines are tightly regulated in the EU and increasingly clean, the secondary ‘donkey engines’ used to power TRUs on many trucks and all articulated trailers are effectively unregulated and emit grossly disproportionate amounts of toxic air pollution. Over the course of a year, a modern trailer TRU emits six times as much nitrogen dioxide (NOx) and 29 times as much particulate matter (PM) as the Euro VI propulsion engine pulling it around. This kind of pollution is estimated to cause 29,000 premature deaths in Britain each year[i], over 400,000 across the EU[ii], and 600,000 in India in 2010 alone.[iii] Refrigeration also accounts for around 20% of a truck’s diesel consumption and CO2 emissions.

The two companies are working to reduce the impact of TRUs: Carrier Transicold, part of the US giant United Technologies, has developed a diesel-fuelled system incorporating CO2 in place of conventional synthetic refrigerants, now being trialled by Sainsbury’s. The Dearman Engine Company, a British start-up, received Highly Commended status in last night’s awards and is developing a zero-emission engine to completely replace incumbent diesel fuelled transport refrigeration systems. Dearman’s highly efficient refrigeration system extracts both cooling and power from the phase-change expansion of liquid air or liquid nitrogen – two bangs for your buck. The system is based on a novel piston engine invented by Peter Dearman in his garden shed in Bishop’s Stortford, and would repay its investment in under three months.

The Dearman Engine Company is working on the first application of the engine with Hubbard Products Ltd, to drive the motor in a transport refrigeration unit (TRU). Part of the worldwide Zanotti group, Hubbard Products Ltd is the UK’s principal designer, manufacturer and supplier of refrigeration systems and units and the leaders in refrigeration for commercial vehicles and refrigerated vans. The technology will be undergoing on-vehicle trials in December at MIRA (formerly the Motor Industry Research Association), which will be followed by commercial trials in 2015 and the manufacture of the first engines in 2016.

Hubbard’s Managing Director, Pat Maughan, said: “Hubbard, after many years of refining designs, has realised that near-term future requirements cannot be achieved with existing available components and technologies. Hubbard has engaged jointly with Dearman to develop a transport refrigeration system that will be the paradigm shift to economic clean cold on the highway.”

Air pollution is rising rapidly up the political agenda in Europe, where the European Commission has started enforcement action against the UK for persistently breaking legal limits on emissions of nitrogen dioxide, which could eventually result in fines of €300 million per year.[iv] A separate ruling by the European Court of Justice in November 2014 also obliges the government to clean up Britain’s air pollution, and applies equally to other EU member states.[v]

Because diesel TRUs are so polluting, the impact of even a modest fleet of Dearman units could be huge. A recent report from the Liquid Air Energy Network (LAEN)[vi] found that a projected fleet of just 13,000 Dearman liquid air refrigerated trailers would reduce NOx emissions by the same amount as taking 80,000 Euro VI trucks or 1.2 million Euro VI diesel cars off the road. It would be the PM equivalent of removing 367,000 such trucks from service – more than three times the entire UK articulated truck fleet today – or 2.2 million Euro VI diesel cars.

The implications of this technology are global. In the UK, online food shopping is growing fast, with the market set to double in value over the next five years to £13 billion according to market researchers IGD. If the additional refrigerated vehicles needed to deliver all this food are not made more eco-friendly, the environmental and health impacts in urban areas could be serious.

The Dearman engine can also offer global benefits, particularly in rapidly industrialising countries where the cold chain is not yet fully established such as India. Here, up to 50 per cent of perishable food is lost before ever reaching a plate because cold chains are rudimentary or non-existent. By using this technology these countries can leapfrog the wasteful and polluting ways of the developed nations.

In many cases innovative fuel-efficient technologies tend to be significantly more expensive than established ones, but the Dearman engine breaks this orthodoxy. As well as being simple, cheap to build and low maintenance, many of the parts needed to make it are readily available in the UK. The engine’s production also offers huge implications for UK Plc. The LAEN report found that production of the Dearman engine could deliver more than 2000 jobs by the early 2020s.

Toby Peters, Dearman’s Senior Group Managing Director and newly-appointed Visiting Professor of Power and Cold Economy at the Birmingham Energy Institute, said: “At the moment cold is treated very much as the ‘Cinderella’ of the environmental debate. But the good news is that there are many promising opportunities for doing cold better and we are delighted that the judges have recognised the Dearman engine and the importance of this sector in the awards. We look forward to proving the value of this technology over the coming months and demonstrating the impact it could have on a better cold chain worldwide.”


[i] R (on the application of ClientEarth) (Appellant) v The Secretary of State for the Environment, Food and Rural Affairs (Respondent),The Supreme Court, 1st May 2013, https://www.supremecourt.uk/decided-cases/docs/UKSC_2012_0179_Judgment.pdf

[ii] Europe’s cities still suffering from harmful air pollution, European Environment Agency, http://www.eea.europa.eu/media/newsreleases/europes-cities-still-suffering-from.

[iii] Air Pollution – A Global Dilema, Gazasia


[iv]R (on the application of ClientEarth) (Appellant) v The Secretary of State for the Environment, Food and Rural Affairs (Respondent),The Supreme Court, 1st May 2013, https://www.supremecourt.uk/decided-cases/docs/UKSC_2012_0179_Judgment.pdf

[v] The Court clarifies Member States’ obligations as regards respecting the limit values for nitrogen dioxide, Court of Justice of the European Union, 19th November 2014, http://curia.europa.eu/jcms/upload/docs/application/pdf/2014-11/cp140153en.pdf; EU Court rules UK government must clean up dangerous air pollution, The Guardian, 19th November 2014, J Vidal, http://www.theguardian.com/environment/2014/nov/19/eu-court-rules-uk-government-must-clean-up-dangerous-air-pollution

[vi] Liquid air on the highway, Liquid Air Energy Network, June 2014, http://media.wix.com/ugd/96e3a4_77f216b9c280408fbfd431a0c8dcd810.pdf

For more information, please contact:-

Caroline Holmes – Automotive PR


Martin Hayes – Automotive PR


+44 (0) 20 7952 1070

Notes to editors:

Cold chain growth

- The growth in global demand for all forms of cooling to 2030 could equate to three times the current generating capacity of the UK.

- The global cold chain is expected to grow 16% per year.

- The rapidly emerging markets in Asia and South America are seeing 25%+ year-on-year growth.

- India projects it needs to spend more than $15 billion on its cold chain over the next five years.

What is liquid air?

Air turns to liquid when refrigerated to -196C, and can be conveniently stored in insulated but unpressurised vessels. Exposure to heat (including ambient) causes rapid re-gasification and a 710-fold expansion in volume. This expansion creates pressure, which can be used to drive an engine piston, and also gives off cold, which can be used to provide refrigeration or air conditioning. Engines running on liquid air (or liquid nitrogen, which is already widely available) are zero emission at the point of use, and can be zero carbon depending on the source of electricity used to make it.

What is the Dearman engine?

Although liquid air cars were first built more than a century ago, the novelty of Peter Dearman’s invention lies in the use of a heat exchange fluid (water and glycol) that promotes extremely rapid rates of heat transfer inside the engine rather than in an external heat exchanger. The Dearman engine is constructed almost entirely from the components of a conventional piston engine, requires little maintenance and has a light environmental impact.

The Dearman engine could be used in a number of configurations: on its own, as the ‘prime mover’ or principal engine of a zero emissions vehicle (ZEV); combined with an internal combustion engine (ICE) to form a ‘heat hybrid’; or as a power-and-refrigeration unit.

Why is Dearman engine refrigeration so efficient?

Vehicle manufacturers and industrial gas producers have begun to offer vehicle refrigeration for trucks and trailers based on the evaporation of liquid nitrogen, but these systems do not extract any power from the evaporation process. The Dearman engine is far more efficient because it extracts both cold and shaft power from the same unit of liquid air or nitrogen. First the cryogen is vaporised in a heat exchanger in the refrigeration compartment, so cooling it down; then the high pressure gas is used to drive the Dearman engine, whose shaft power can be used to drive a conventional refrigeration compressor or for auxiliary power. The Dearman system therefore delivers two bangs for one buck.

Why does vehicle refrigeration matter?

Transport refrigeration today is overwhelmingly powered by diesel. The Transport Refrigeration Unit is a compressor driven either from the vehicle’s main engine, or on larger trucks and trailers by a secondary unit known as a ‘donkey’ engine. Either way, refrigeration can consume as much as 20% of a refrigerated vehicle’s fuel, causing CO2 emissions of almost 50 tonnes per vehicle per year from refrigeration alone.

Donkey engines are currently unregulated, which means they typically emit far higher levels of nitrogen NOx and PM than a modern truck propulsion engine (Euro VI). An analysis of regulatory standards suggests that a trailer refrigerator engine emits six times as much NOx and 29 times as much PM than a Euro VI truck engine. These emissions cause respiratory illnesses and 29,000 premature deaths in the UK each year.

Proposals to strengthen the regulations governing Non Road Mobile Machinery (NRMM Stage 5) are expected to be adopted by the European Commission (EC) this year, and may come into force by 2019-2021, but will make essentially no difference to the emissions of NOx and PM from transport refrigeration units.


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