Fruit Logistica 2020

•••9••• Innovationen Cooling without electricity Student research could help keeping produce fresh in remote places T he key to the functioning of this simple, inexpensive sys- tem is a special kind of insulation, made of a polyethylene foam called an aerogel. This lightweight material, which looks and feels a bit like marshmallow, blocks and reflects the visible rays of sun- light so that they don’t penetrate through it. But it’s highly transpar- ent to the infrared rays that carry heat, allowing them to pass freely outward. A new system is described in a pa- per by MIT graduate student Arny Leroy, professor of mechanical engineering and department head Evelyn Wang, and seven oth- ers at MIT and at the Pontifical Catholic University of Chile. The system is a device, which has no moving parts, and it works by a process called radiative cooling. It blocks incoming sunlight to keep from heating it up, and at the same time efficiently radiates in- frared light – which is essentially heat – that passes straight out into the sky and into space, cool- ing the device significantly be- low the ambient air temperature. “Such a system could be used, for example, as a way to keep veg- etables and fruit from spoiling, potentially doubling the time the produce could remain fresh, in re- mote places where reliable power for refrigeration is not available,” Leroy explains. Radiative cooling is simply the main process that most hot ob- jects use to cool down. They emit midrange infrared radiation, which carries the heat energy from the object straight off into space because air is highly trans- parent to infrared light. The new device is based on a concept that Wang and others demonstrated a year ago, which also used ra- diative cooling but employed a physical barrier, a narrow strip of metal, to shade the device from direct sunlight to prevent it from heating up. That device worked, but it provided less than half the amount of cooling power that the new system achieves. Keeping produce fresh without reliable electricity is often a challenge. Photo: Dan Meyers FRUIT LOGISTICA 2020 5.–7. Februar Berlin, Deutschland Hub27, Stand F-11 GLOBALG.A.P. News Update 6. Februar, 12:30–13:30 Uhr Halle 6.3 (Pressecenter), Raum B GLOBALG.A.P. Reception 6. Februar, 13:30–14:30 Uhr. an unserem Stand www.globalgap.org/events