Nisa intends to install NatureFridge cryogenic refrigeration units on all its replacement trucks at its Harlow depot, says Jonathan Stowe, Distribution Director, Nisa.
Nisa has trialled two vehicles using NatureFridge: a Volvo 26t rigid with a Solomon Slipstream body and an 11-m tandem axle Gray and Adams refrigerated trailer. Both are multi-temperature with longitudinal lanes used for deliveries to Nisa independent retailers. The vehicles will remain in service following the trials.
The vehicles use a cryogenic refrigeration system powered by liquid nitrogen.
"The main benefit of using Naturefridge for Nisa relates to product integrity", says Stowe. "As a multi-drop operator, during the summer months it is particularly challenging to maintain vehicle chamber temperature when the doors are being opened pretty much every half hour.
"Mechanical refrigeration really struggles to maintain integrity in these conditions. However, the NatureFridge system can pull the temperatures straight back down and therefore give us greater control over delivering a first class product to our customers.
"Other benefits relate to the lack of blast chilling that can adversely affect sensitive products, and the feedback from our members is that the product is ‘fresher’ and in better condition than that being delivered by mechanical refrigeration vehicles," Stowe says.
Fuel costs for NatureFridge and traditional diesel fridges are about the same, he says. "The cost benefit arises from much lower maintenance costs each year. However, part of our work with Naturefridge resulted in a modification to reduce nitrogen consumption. During hot spells the Naturefridge system works continuously, but we now have a setting outside of hot weather that allows the Naturefridge to ‘cycle’ in a similar way to a mechanical fridge and this allows a significant reduction in nitrogen used."
Low noise is an important consideration for Nisa because a large number of stores are in highly residential areas. "The Naturefridge system being totally silent is very valuable to us – and was a key feature of our night-time deliveries in London during the 2012 Olympics," he says.
"Equally important is the environmental benefit that the Naturefridge system emits zero CO2 emissions and therefore is an important part of our corporate social responsibility improvement plan."
The trials have shown that total life costs of the Naturefridge system are identical to a mechanical fridge with the slight increase in capital cost being off-set by lower maintenance charges. "The benefits are not only product integrity and silent running but also the reliability of the system. With so few moving parts there is very little to go wrong with the Naturefridge system which gives it a distinct advantage over a mechanical unit," says Stowe.
NatureFridge, sold in the UK by M1 Transport Refrigeration, is an upgraded version of the EcoFridge system first developed in 2001. NatureFridge is a refinement, borne from the various trials carried out over the last five years.
A typical rigid system with 650-litre nitrogen tank storing gas at 1.5-bar will last up to 26-hours between filling depending on the load temperature and outside temperature. A 950-litre trailer system will last up to 39-hours between fills. For mixed frozen and chilled loads with frequent door openings the consumption rate will be higher as is the case with any refrigeration system.
"Depending on running hours, natureFridge offers users a saving of around 25-tonnes of CO2 per trailer per year. And that also means a significant fuel saving. Every hour a typical diesel-powered trailer refrigeration unit consumes about 3-4 litres of diesel and emits around 10.52kg of CO2. NatureFridge eliminates all that," says Liam Olliff, Managing Director, M1 Transport Refrigeration.