Young inventor's solar-powered fridge changes lives in Africa
February 13, 2009 Solar powered devices aren’t new – you can recharge your iPod and laptop in the most remote locations, stay in a solar-powered resort and buy any number of ‘cool’ gadgets - but English student Emily Cummins has developed a way of using the sun’s power to help impoverished communities in Africa. Her eco-friendly, sustainable fridge is based on a simple principle: it uses the sun’s rays to evaporate water, which in turn keeps the contents cool.
The cylindrical fridge, so shaped as it has fewer areas where bacteria can build-up, can store perishable items for several days at a temperature of 43 ºF /6 ºC (a second generation fridge that maintains an even lower temperature and is more energy efficient is in development).
Emily spent five months living in a township in Namibia during her Gap Year, testing the fridge, looking at available materials within the community and showing local people how to make their own fridges.
The fridge is made using two cylinders, one inside the other. The inner cylinder is made of metal while the outer cylinder can be made from any solid material with holes drilled in the side, enabling communities to recycle and use local, sustainable resources. The space between the cylinders is packed with sand, wool or soil, and then water is added. As the sun warms the mixture the water evaporates cooling the inner cylinder. Fresh water is added to the mixture as needed.
While the fridge helps people keep their perishables such as meat and milk cold, it could also be used to carry valuable medical supplies in hot climates.
Australian ingenuity came up with a similar idea back in the tough gold rush days in the 1890s when necessity was the mother of invention. The Coolgardie Safe used the same principles of heat transfer and water evaporation to keep food cool in the harsh Australian climate and was still used up until the mid 1900s.
Emily is no stranger to ingenuity and inventing; from the day her grandfather, an engineer, gave her a present of a hammer at the age of four she spent hours making things from seemingly random bits and pieces.From those early beginnings she went on to design a toothpaste dispenser for people with arthritis and a water carrier that won a Sustainable Design Award.
At this awards ceremony Emily heard a speaker talk about the effects of global warming: it got her thinking about how to reduce the amount of fossil fuels being burnt and how she could make a difference. Her research showed that the fridge is the main appliance that people could not, or did not want, to live without so she began working on her prototype for a sustainable version.
Her entrepreneurial spirit has not gone unnoticed. At just 21 Emily has won numerous awards for creativity, innovation and sustainability including British Female Innovator of the Year 2007 and the Technology Woman of the Future Award. She was appointed Women of Achievement Ambassador - 2007-2008 and in November last year became one of the Future 100 Entrepreneurs of the Year. She also speaks at conferences and events encouraging and inspiring other young people to bring their ideas to life.
Emily is currently studying Business Management at the University of Leeds in the UK while continuing to work on sustainable technology projects.
It’s a powerful combination and one that will hopefully enable her to make an even bigger difference to the world.
For more information about Emily take a look at her website and blog.
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The design is more refined, elegant and effective.
Simple physics tells us EVAPORATION PRODUCES COOLING. Based on this principle several models of POORMAN\'S FRIDGE with concentric mud jars were made by many in the past. Also simple covering of gunny bag (made of Jute) and keeping it wet on a container keeps the contents cool. Traditionally people carry water in canvas bags while travelling. Canvas bags have pores. Here again the principle is evaporation produces cooling. I made an AIR-CUM Water cooler by suspending two canvas bags at a distance of two feet and putting a table fan / pedestal fan behind it. This way the room gets cooled and also the water inside the canvas bags. One can takeout water in canvas bags for drinking purposes and filling the bags with fresh water. If one wants more cooled water, one can have many bags (about 10) suspended in a semi-circular way and putting the table fan/pedestal fan in oscillatory motion. These way small hotels in villages can get cooled drinking water at an affordable price. Of course this system works in less humid areas.
Dr.A.Jagadeesh Nellore (AP), India