Milk is a staple product, but maintaining temperature from processing plant to retail shelf remains a persistent challenge across the cold chain. In most cases, transport relies on diesel-powered refrigeration units, adding both cost and emissions to distribution.
Work underway at the University of Auckland is exploring an alternative approach that shifts the focus from active refrigeration to stored thermal energy.
Emeritus Professor Mohammed Farid, from the University of Auckland’s Faculty of Engineering and Design, says the system is designed to maintain stable temperatures during transport without relying on continuous mechanical cooling.
“Phase change materials can store and release thermal energy, allowing us to keep products within a narrow temperature range during distribution,” Farid says.
The portable system uses panels filled with phase change materials, combined with fans and a temperature controller, to maintain milk at 4–5°C, the range required to preserve quality and shelf life.
Farid says the unit is designed to operate under real delivery conditions.
“The unit is loaded into trucks alongside product, and the fans operate under a controller to distribute cool air evenly throughout the load.”
That becomes particularly relevant in multi-stop delivery runs, where frequent door openings introduce warm air into the vehicle.
“The phase change materials help absorb heat when doors are opened and reduce temperature fluctuations during the day,” Farid says.
The technology has been developed through PhaseFoam and is currently being trialled with ELS Distribution, a Takanini-based operator delivering Fonterra milk across New Zealand. Trials over the summer period have been used to test performance under higher ambient temperatures.
Farid says the goal is to match the performance of conventional systems while reducing emissions.
“The aim is to achieve the same level of cooling performance as diesel-powered systems, but without the associated fuel use.”
Alongside transport trials, the concept has also been tested in smaller-scale applications, including chilled storage using produce to monitor spoilage through carbon dioxide levels.
While developed around dairy distribution, the same approach is applicable across temperature-controlled manufacturing and logistics, including chilled food, pharmaceuticals and chemical handling.
Farid says the system is intended to integrate into existing operations.
“The objective is to provide a solution that can be integrated into existing operations while improving efficiency and reducing energy demand.”
Temperature control remains a core requirement across production and distribution, particularly where energy use, cost and product integrity are involved.