Shpogy Secondary SchoolResearch work in English Authors: Laura Lāčauniece, Jānis Stupelis The Adviser of the Research Work: Eva Vovka Shpogy, 2013
The aim:• To make a solar cooker from recycled materials at school.The tasks:• To collaborate with the Comenius partners and share the experience on the issue mentioned in the aim of the research work.• To collect theoretical information about a solar cooker;• To make the solar cooker;• To test it;• To compare our solar cooker with the cookers of our Comenius partners;• To summarize the results of the research work and present the results.Methods: work with literary resources,observation, research, analyses, comparison
Theoretical PartThe sun is one of the humanitys most important tool forsurvival. It gives off unlimited amounts of light and heat.Natural and simple technologies like solar cookers canreduce or even replace fossil fuels, they do not producewaste. Moreover, materials to build it can mostly be foundfrom recycled sources which makes it even moresustainable.A solar cooker is a device which uses the energy ofdirect sunlight to heat, cook or pasteurize food or drink.
Panel cookers.• This cooker works by means of a parabolic reflector, which concentrates the rays of the sun on the pan and heats it. It is possible to reach high temperatures and, consequently, besides cooking, it is also possible to bake and fry.• The only task for the cook is to rotate the cooker about every 20 min in order to orientate it towards the solar rays. It is because of the earth’s rotation.• These are in use in refugee camps around the world.
Box cookers• It was first built by Horace de Saussure in 1767; Later Augustin Mouchout developed the idea of solar cooking.• 90–150 °C temperature can be reached. For best results clear sunny days are necessary.• It has a glass or Plexiglas cover, this cover is like a greenhouse window- it lets the sunlight in but does not let infrared radiation out. This type cookers also have a reflector which increases the amount of energy the cooker receives. This device exploits solar energy to cook food or just heat it.
Parabolic cookerThe first parabolic solar cooker was developed in the 1950sby M L Ghai at the National Physical Laboratory (NPL) inDelhi, India. These ovens are usually made having a concave disks thatfocus the light onto the bottom of a pot. They cook foodabout as fast as on a conventional stove. Since theconcentrated sunlight shines directly on the bottom of apot, the pot heats up and cooks very quickly.Widely used in China.
Practical part • Panel cooker: cooker • To make a solar cooker we need a shiny surface to reflect and concentrate the Sun’s energy. We took an aluminum bowl.• We had few sunny days in winter. We could not make a real solar cooker by using solar power as an alternative we took a lamp
ExperimentIn 20 min the cooker reached 35 °C temperature and chocolate started to melt. In 40 min the cooker reached 70 °C temperature and candle started to melt.
ConclusionThe research work is based on Comenius activity- sustainableor renewable energy resources. Science teacher Dr Rajinderfrom Germany gave a lecture how to make a solar cooker andten countries made the cookers. He wanted to tell us thatrenewable energy is important and beneficial:•Environmental benefits;•Energy for next generations;•Workplaces and the economy;•Energy security.Unfortunately the survey carried out proves that in Latvia wehave poor awareness of sustainable energy resources. It isstrongly recommended to assess the priorities and to thinkabout the future.