Starbucks and Marks & Spencer are testing delivery fleets equipped with a refrigeration system that generates zero emissions compared with 63.4 kilograms per day for an equivalent diesel-mechanical unit.
The refrigeration system uses liquid nitrogen at -196 degrees Celsius to indirectly chill the truck compartment. The refrigeration unit operates at around 97 percent thermal efficiency, meaning most of the available capacity of the liquid nitrogen is captured with as little as 3 percent escaping into the atmosphere.
The delivery freezer trucks, called FrostCruise, is not reliant on the vehicle engine running to maintain the cooling process. Existing diesel operated refrigeration systems often require drivers to leave their vehicles running while dropping off goods or after off-loading. In some operations, drivers restock stores during the evening, using more fuel and producing noise and emissions in urban environments, Linde says.
The technology used in the freezer delivery trucks has been awarded the UK Noise Abatement Society’s quiet delivery certificate because it operates in near silence.
Several other retail stores are testing refrigeration systems that produce fewer emissions and are more energy efficient.
Plug Power received $500,000 earlier this month from the New York State Energy Research and Development Authority (NYSERDA) to evaluate replacing diesel generators with hydrogen fuel cells for powering transport refrigeration units on trailers hauled by trucks that deliver perishable goods.
In September, UK grocery chain Sainsbury’s announced it was working with transport refrigeration specialist Carrier Transicold to test what it says is the world’s first naturally refrigerated trailer to transport chilled and frozen goods. The CO2-refrigerated unit trial is part of the retailer’s review of its transport refrigeration gas as it aims to reduce its carbon footprint, which includes converting its stores to natural refrigeration by 2030.