Energy-efficient refrigeration wins engineering award

5 September 2001

Keeping food fresh for up to a year in the Antarctic is harder than it might seem, but an innovation by a member of the Australian Antarctic Division's engineering group has made it that much easier, as well as more energy-efficient.

A new 'Coldpump' cold-store system now in use at Mawson station, 5462 km southwest of Hobart, has been given a 2001 Tasmanian 'excellence award' by the Institution of Engineers Australia.

The 'Coldpump' system meets the challenge of keeping the food at a precise temperature and humidity - thereby maintaining its taste and freshness - while cutting energy use to only about a 20th of that needed by the previous system - seven kilowatts a day compared with 134 kilowatts a day.

Food storage is a critical aspect of maintaining year-round stations in Antarctica. With ship visits to stations impossible for up to nine months through the non-summer period, food must be kept for a very long time. At this time of year, outside temperatures fall to well below zero.

AAD technical officer Murray Price was faced with the challenge of developing storage conditions that maintained the taste of food towards the end of the storage period while reducing the demand on energy.

Murray knew that perishable foods can be stored safely for long periods only at precise temperatures and at a high relative humidity. Putting aside conventional refrigeration compressors and gas, he looked for a system that could draw directly on cold outside conditions to keep stored food cool without drying it out.

The new system comprises external panel radiators and a system of pipework, pumps and valves which expose coolant (a glycol-water mix) to the low external temperatures then delivers it to fan-coil units inside the coldstore to precisely regulate the internal temperature.

On the occasions when external temperatures rise too high to maintain the desired storage temperature, a standard compressor-driven refrigeration plant is brought into play.