Nobody can deny that a wave of innovation is sweeping over Uganda. First there was the electric car, waste management systems, and incubator, among others and now there is a solar-powered cooker. The solar cooker was unveiled last week at this year’s annual general technology innovation exhibition organised by the College of Engineering, Design, Art and Technology (CEDAT), Makerere University. Solar technology is not a new phenomenon.
According to Chris Keenan, a blogger at Clean Technica based in the US, using solar cookers is one of the energy sources used in ancient times by the Romans.
“They used mirrors and glass that didn’t just give light to their homes and bathhouses, but also enabled them to create ovens, he says.
Major cities of Rome were often crowded and wood for fires was sometimes hard to get. The citizens took the Greek idea of using glass to magnify heat and applied it for use as an oven. Since then, the technology has progressed and the use of solar cookers has spread worldwide.
In his report, Keenan further adds that using a microwave oven is more eco-friendly than a regular oven, but expresses concerns about the safety of the metals in the ovens.
“…This is not so with solar cookers and when it comes to food taste, microwaves can alter food taste unlike a normal oven.” The preservation element is one of the reasons why chefs prefer using solar cookers.
But in Uganda, the appreciation for solar cookers is to address an energy crisis as a large percentage of the population depends on biomass which has led to depletion of trees.
The five innovators who are graduates of quantitative economics say their innovation relies purely on sun rays and is not dependent on a solar panel.
Dan Maire, the group leader, says they decided to pursue the idea of making a solar cooker last year. Asked if this was a random innovation, Maire says his motivation to develop an energy saving tool started four years ago.
“I got interest to develop energy saving technology for rural communities in 2012 when I was a Senior Six student at St Paul’s College, Mbale. I was a member of the education club and teachers used to encourage us in develpoing business skills. Other members and I participated in a skill innovation competition where we assembled boxes with aluminum foil which we used to boil eggs for the judges. We emerged victorious and the school rewarded us with Shs500,000. I also received a golden-embroidered certificate because I was the brain behind the innovation,” he explained.
Realizing that he had the potential, Maire continued to research on how to develop better energy saving cooker. And his efforts paid off last year.
In 2015, Maire and his colleagues searched for companies that support innovations related to energy on the Internet. They zeroed down on a company called Blazing Tube Solar appliance based in the US.
They wrote a proposal to John Grandinetti, the director of the company, seeking for materials they could use to assemble solar cookers.
The group also conducted a market study for cookers free from gas emissions in Karamoja, Lango and Acholi sub-regions as well as West Nile. Realizing the great relief solar cookers would present to the people in the sampled areas, Maire and his team took a leap.
“We sent prescriptions of the materials we needed and Mr Grandinetti connected us to the person in charge of such consignments and the company shipped the materials to Mombasa but my family had to raise $2,800 (about Shs9.6 m) for transportation from Mombasa to Kampala.”
With everything needed in place, the group went on to assemble 80 units of solar cookers in July. The merchandise is in their stores in Bukoto, a Kampala suburb.
The solar cooker contains a cook box where the cooking saucepan is placed. Inside the cook box there is a provision for storing six litres of cooking oil to help in generating heat from the sunlight while cooking. The cooking oil which acts as transfer fluid can be used for a period of one year before it is replaced.
There is a vacuum tube connected to the cook box extending through to the stand where reflector sheets are constructed on the sides to attract sun rays.
The stand contains plastic piece of sheet which can be rolled over the standing frame to regulate the flow of heat.
Dr Henry Alinaitwe, the Principal CEDAT, said it is through science, technology and innovations that countries are now growing, giving example of China where 2.5 million engineers graduate every year compared to Makerere University’s 200 engineers.
He said initiatives such as solar cookers are good for the environment because they help solve the challenge of deforestation
“Where trees have been cut down and sold as cooking fuel and charcoal production leads to deforestation which in turn has caused radical change in weather pattern. We see regular food shortages and famines, extended drought and flooding and many villages lacking trees for firewood, solar energy is the best substitute,” he noted.
Before you set the cooker ready for cooking, the stand containing the reflector must be positioned to face the direction where the sun is rising or setting to get the sun rays for absorption. Then it has to be pre-heated for 90 minutes to enable stability of the heat ratio.
There is back up heat supply which is assembled beneath the cooker where brickets or charcoal is put in case someone is cooking when there is no sunlight. On the unit, there is a thermometer attached for purposes of measuring the temperature which should not exceed 75 degrees Celsius.
Each unit cost $360 (about Shs1,242,000) to assemble a price that would be on the high end for the intended people.
Maire says his team is not focusing on selling these units to individuals but rather interested in partnering with organisations such as Food and Agriculture Organization, World Food Programme and other development partners who are willing to enter into a contract with them in order to assemble the cookers for rural communities who are dependent on firewood as source of energy.The group has approached UNDP to partner with them but they have been asked to register as a non-governmental organization to make their operations formal which they are in the process of doing.
“If communities can form village associations in a bid to purchase these units which can be used as a group it will be better. Another target group is schools that cook for large number of students. This is because apparently the size is bulky and we are right now trying to come up with potable sizes which can be used at household level,’ he noted.
It is important to encourage students and graduates alike to come up with initiatives that help address the challenge faced by communities in accessing sources of energy for cooking with the major one being use of biofuel. Support can be given through linking the innovators to easily accessible markets for their innovations.
Similarly, alternatives such as use of solar cookers should be embraced by communities because it provides clean energy and more so accessing energy from the sun is less costly compared to purchasing charcoal and firewood.
How does solar cooking work?
What it entails. Solar cooking is done by means of the suns UV rays.
A solar cooker lets the UV light rays in and then converts them to longer infrared light rays that cannot escape. Infrared radiation has the right energy to make the water, fat and protein molecules in food vibrate vigorously and heat up.
Big puzzle. It is not the sun’s heat that cooks the food, nor is it the outside ambient temperature, though this can somewhat affect the rate or time required to cook, but rather it is the suns rays that are converted to heat energy that cook the food; and this heat energy is then retained by the pot and the food by the means of a covering or lid.
Tracking the sun. For maximum efficiency it is necessary to “track” the sun, or in other words adjust your solar cooker so that it is directly towards the sun in order to be able to better concentrate and absorb the suns rays.
This does not mean that you must continually stand beside the solar cooker the whole cooking period.But it can mean adjusting the angle and direction every so often or every set period, such as every one to two hours
Changes. Cooking can be accomplished as well on days when the clouds are high and thin, but it may slow things down a bit, and one would be wise to start a little earlier than usual.
Variations. Long, slow moderate solar cooking, such as with stew, chili, veggies etc. will do fine under less than bright skies if you allow more time.
Baking on the other hand will take longer and the temperatures will not be as optimum as could be, thus resulting in mixed outcomes with your baked goods.