Sainsbury’s has become the first company to introduce a refrigerated delivery truck cooled by a liquid nitrogen powered engine (earlier post), which will eliminate all emissions associated with refrigeration. Supplied by cooling technology specialist Dearman and its partners, the zero-emission cooling unit replaces the traditional diesel engine used to chill the vehicle and will significantly cut emissions.
During the three-month trial, the vehicle will save up to 1.6 tonnes of carbon dioxide; the equivalent of driving more than 14,500 km in a modern family car. The trial will also save 37 kg of NOx and 2 kg of particulate matter, compared to a similar diesel system. The truck will operate from Sainsbury’s Waltham Point depot, delivering chilled goods to stores in the London area.
Based on the Dearman Engine, the new system harnesses the rapid expansion of liquid nitrogen to deliver zero-emission power and cooling.
The Dearman Engine operates by the vaporization and expansion of cryogenic fluids. Ambient or low grade waste heat is used as an energy source with the cryogen providing both the working fluid and heat sink. The Dearman Engine process involves the heat being introduced to the cryogenic fluid through direct contact heat exchange with a heat exchange fluid (HEF) inside the engine.
Traditionally many refrigerated trucks require two diesel engines, one to power the vehicle and one for the refrigeration unit. By replacing the latter, Dearman believes that a more sustainable solution for refrigeration may soon be widely adopted.
In addition to being a cleaner method of refrigeration, the new engine has been designed with safety in mind. Unlike traditional fuels such as diesel, liquid nitrogen (LIN) is a non-flammable substance, which is used extensively in industry and food preparation and is transported safely on the UK’s road network. It has been provided, along with the refueling infrastructure, by Air Products.
The Dearman Engine is the basis for a suite of zero-emission power and cooling technologies being developed by the company, which have applications across transport and the built environment.
The development and deployment of this technology has been made possible by Dearman’s partners: Hubbard Products (earlier post); Dawsonrentals and Air Products. Hubbard has provided world leading expertise and operational support, contributing their own refrigeration technology and systems integration. Dawsonrentals has provided use of a state-of-the-art refrigerated vehicle and has supported project coordination. Air Products has contributed expertise in cryogenics while supplying the liquid nitrogen and refueling infrastructure.
The trial is the latest in a series of innovations from Sainsbury’s as the retailer works towards its commitment to reduce absolute carbon emissions by 30% between 2005 and 2020. Following a trial in 2013, it became the first company in the world to use CO2 as a natural refrigerant and has now taken on three trucks with cooling fueled by this method.
Earlier this year the company introduced R-452A as a cooling agent in its transport and announced that all new fridges would run on this. R-452A is recognized as a cleaner cooling agent and will help reduce emissions by 45%, compared to the R404A more commonly used. Assessment of the success of the trial will be considered, along with operational cost on any potential for roll out of the technology.