4 learners from Levana Primary School in Lavender Hill have been selected to participate in the semi-finals of the annual ESKOM eta Awards to be held in Johannesburg today..
Through this competition Eskom rewards excellence in the field of energy efficiency. (eta) is the Greek symbol for efficiency, hence the name of the Awards. The purpose of the eta Awards is to reward exceptional effort in the more efficient use of energy by individuals, students, companies or other institutions.
The grade 7 learners submitted their entry – a project about Alternative Methods of Passive Refrigeration – in the group category for Young Designers: specifically for school-going learners who created, designed or developed innovative efficient energy applications. This could be creating new, innovative products, reducing energy consumption and creating awareness about energy efficiency at school or in their communities.
The eager group of learners, along with their co-ordinator, Rene Swart, from the ESKOM/WESSA (Wildlife and Environmental Society of South Africa) Energy and Sustainability Programme, initiated the project in May 2013. Once learners understood that at any time they used electricity they were contributing to climate change, they decided to investigate the different ways in which we consumed energy. They decided that the two appliances we could ‘not live without’ were a refrigerator and stove and it was here that the eager team decided to begin their investigation into Refrigeration.
The group’s ultimate aim with the project was to draw attention to Alternative Methods of Passive Refrigeration for households that did not have access to electricity or did not have the means to purchase refrigerators, and then compare the different methods highlighted to determine which was the most efficient in terms keeping perishable foods fresh for longer. Passive Refrigeration means to make use of alternative methods to keep our food from spoiling without using any electricity whatsoever. They also wanted to determine exactly how much electrical energy was being expended on keeping our fresh food fresh!
The project objectives were to:
Calculate the electrical consumption of an average household refrigerator – according to their investigations it was found that a single average fridge consumes approximately 690 kWh per year – this equates to about R607.00 per year – just to run our fridge!
Learners also wanted to determine the environmental impact of fridge use and therefore also calculated the carbon footprint.
The promising young scientists sought to compare 4 different methods of alternative refrigeration and determine which was the most efficient in terms of keeping perishable foods fresh for longer.
The designs they developed and investigated were: A pot-in-pot Evaporative Cooler, using two clay pots, one inside the other with a layer of wet sand between them.
- An Evaporative Box Fridge – using wet hessian to cover a shelf-system.
- A Radiant Cooler using infrared radiation at night to make ice blocks to use in their Cooler Box.
- Cooling by burying the food in a sealed box in cold ground that is shaded from the sun.
Perishable foodstuffs were placed in all four the devices and daily temperatures inside the ‘fridges’ were recorded and compared. At the end of their investigations learners had to evaluate their findings and determine which method was the most efficient in keeping the produce fresh for the longest time.
Those of us connected to the electricity supply grid have access to every modern, low cost convenience conceivable. Yet those not connected to the grid often have to make do with alternatives. This lack of access to grid electricity in remote regions seriously limits rural communities’ access to modern technology, hindering their development and forcing them to rely heavily on unsustainable resources.
Utilizing alternate or passive methods of refrigeration for food will be considerably more cost effective in terms of saving money on electricity as well as doing our part to conserve resources.
Ignorance is one of the greatest sources of energy waste in homes and we want to promote the importance of maintaining refrigerators correctly in order to encourage energy efficiency and address ways of reducing our energy consumption by becoming good environmental stewards.
We wish these 4 bright, burgeoning young innovators the best of luck with their presentations in Johannesburg!
(contribution by Ivor Nober, principal of Levana primary school)