Energy-efficient refrigeration wins engineering award

Keeping food fresh in the Antarctic is harder than it might seem, but an invention by Australian Antarctic Division engineers has made it that much easier while making the refrigeration process more energy-efficient.

A new 'Coldpump' cold-store system now in use at Mawson station, 5462km southwest of Hobart, has been given the top award in its category in the Institution of Engineers Australia's Tasmanian Engineering Excellence Awards for 2001.

The Coldpump system has markedly improved the taste and freshness of vegetables, fruit and dairy products kept in storage for long periods.

Food storage is a critical aspect of maintaining year-round stations in Antarctica. With ship visits to stations suspended 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 engineer Murray Price was faced with the challenge of developing storage conditions that improved the taste of food towards the end of the storage period while reducing the demand on energy. Energy to drive refrigeration plants is currently provided by diesel-powered generators - to be largely replaced in a few years by wind-generated power.

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 air to cool stored food.

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

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