At primary school Rainbow4kids a solar collector was constructed to heat up water and reduce the energy cost and the kitchen and cooking process were optimized.


The Rainbow4kids primary school is situated in Ukunda, Kenya and educates over 350 pupils. The population of Ukunda is mostly underprivileged and often has difficulties providing food for their children. Therefore the school offers the pupils two proper meals a day prepared by the combustion of fire wood. Since the cooking installation has a low efficiency, it requires a large amount of firewood causing the energy costs to rise through the roof. Besides the financial consequences it also has an impact on the environment. In addition big and heavy cooking pots are being used which are very difficult to handle. During the cooking process, the kitchen fills up with smoke and the the temperature rises making working very unpleasant.

Since this project is quite extensive it was divided into two parts with on one hand the durable energy installation to heat the water and on the other hand the optimization of the cooking process and the kitchen.

Solar collector

After a thorough study for the best energy solution, engineering students Jason Serdons and Sven Bonhomme decided on a solar trough. However once on site in Ukunda the situation forced them to change plans and opt for a solar collector instead. This installation is less complicated and doesn’t need an electronic control system.

A solar thermal collector utilizes the sun’s energy and convert it into heat. The installation constructed in Ukunda consists of solar panels with a grid structured netwerk filled with glycerine and a heat exchanger inside a water tank. The sun’s rays heat the glycerine inside the netwerk that is pumped to the heat exchanger where it transfers the heat to the water inside the tank. The solar collector was realised with local materials in cooperation with local contractors. The heated water (up to 65 °C) is directly used in the kitchen which decreases the energy cost by 25 % (or 500 euro per year).

Read all about their Kenyan adventure on their blog.

Optimization kitchen and burning process

After installing the solar collector, Sven and Jason passed the torch to students Pieterjan Oudebrouckx and Simon Wauters to optimize the cooking process and the kitchen. At that point they had already performed a literature study to design a new efficient, sustainable and ergonomic furnace. This consisted out of a rocket stove principle using wood as fuel and two separated cookers, one single and one double cylinder type. Once in Ukunda they looked for locally available materials, adapted the design and constructed the furnace. They also installed a crane to lift the heavy cooking pots improving the ergonomics of the kitchen staf. Additionally the temperature in the kitchen doesn’t rise so much anymore and it is smoke free.  Tests showed a decrease in the usage of wood by 38 % (or 570 euro per year).