User:Insight.121212/sandbox

Home Made, Cheap Solar Cooker
Goa is still very beautiful except for a few places where some people want to make lots of money whatever the cost. They have forgotten why tourists come to Goa in the first place. Some parts of our lovely sand beaches have more rubbish than sand. Used packaging & glass bottles thrown along the road sides make beautiful Goa look so dirty. Many people have built houses in rice fields & dug wells supplying swimming pool water to hotels. Dumping plastics, rubber & other waste is creating a mess & huge health problem. Burning them sends harmful smoke & gasses into the atmosphere where it forms a blanket around the earth trapping heat that is melting the polar ice. This will raise sea levels & could drown us some day. Along with cutting of trees for firewood, buildings or mining all this is harming the whole eco-system. The only way to save our environment is to recycle things with sustainable energy. Tetrapac cartons from juice, milk etc are now being recycled into corrugated roofing sheets. Old clothes & sugarcane juice waste are turned into paper. Glass bottles or plastic packaging can be melted & remoulded. If we all get together to collect & dispose our waste correctly we can have a clean, healthy & beautiful habitat for all living things.

The Bible says God has given man power over everything on earth which gives us the responsibility to look after it. Man being at the top will be in big trouble after he has destroyed everything under him. By not taking care of our environment we are slowly but surely killing every living thing along with ourselves. Birds & animals not only look much better live in nature than on TV but also have a very important part in the eco-cycle. Snakes eat frogs & rats that destroy our crops but rats also control worm population. Frogs eat larvae, mosquitoes & insects that spread diseases like malaria & damage crops. Even the annoying crows help clear dead rats & food waste thrown around by irresponsible people. It is important to learn which animals are dangerous to us but as even the dangerous ones have a role in nature we should call the forest dept. to relocate them instead of killing every snake we see. Wild animals are very shy & avoid humans unless we destroy their habitat or build houses in their territory. If we kill animals like snakes, frogs, it upsets the balance in nature causing all kinds of trouble for humans.

Fossil fuel is limited so it will get more expensive & finally run out hence we should use it carefully and try to use other types of energy. Hilly areas can use wind energy to generate electricity. Goa has plenty of sunlight so gadgets like solar lanterns, cookers and water heaters work very well almost the whole year. We can buy fancy looking expensive ones or learn how they work & use our imagination to redesign & make them our self which can be cheaper, more efficient & environment friendly. Mother Nature can support us for years to come only if we give her a hand. Our future on earth depends on the way we treat the environment today. Therefore children should be even more eager than adults to see that our lovely blue planet does not end up like the other barren inhospitable planets in our solar system.

Science is my favorite and I love making things I imagine or improving designs using local eco-friendly materials as my parents always stress this. Last year my classmates & I made a battery powered telegraph transmitter/receiver for my school science fair & even studied the ‘Morse Code’ to demonstrate this. This year we had a choice of projects including a biogas plant – too messy, wind powered generator - too big to carry, papier-mâché model of excretory system – too time consuming etc…. and a solar box cooker. I thought it would be great to make something actually useable instead of a show piece. None of my classmates had chosen it so mine would be unique. I discussed with my parents about making it & visited Goa Energy Development Agency (GEDA) to find out how one works. We saw a metal & glass model available with subsidy but still quite expensive.

From the internet I learned that a French-Swiss scientist Horace de Saussure built the first solar cooker in 1767. The basic principle is that its fuel - the direct and reflected sun light energy enters through its transparent top. When this light is absorbed by the black cooking dishes it is converted to heat that is retained by ‘the green-house effect’ inside the cooker. Black surfaces absorb light energy quicker & thin metal heats faster. Therefore food cooks best in black, shallow, thin metal dishes.

I realised this need not be an elaborate factory-built apparatus but easily home-made with cheap, eco-friendly materials & still be just as efficient. With my younger brother helping to hold things, cut cellotape etc., I built a working, recyclable, bio-degradable solar box cooker from a cardboard carton, cellophane, kitchen foil, rice husk & cello tape altogether costing under Rs. 50/- (excluding cooking dishes). At home we cooked quiche, veg. pulao & chicken xacuti solely by sunlight.

As this was my Std.X science project, I set up the cooker in school when we started at 08.15 am to cook cheese mushroom quiche for a demo. It was such a hit that I was requested to bring the cooker back for three days & students brought ingredients to cook quiche, noodles & bread pudding that we enjoyed at recess

About a month later I read a front page article in the 'O Heraldo' dated 4th Nov. '12 about housewives waiting months for their booked solar cookers. On 11th Nov. 2012, ‘The Navhind Times’ said "the North Goa MP, Mr Shripad Naik, said that energy conservation is the need of the hour and children should make every effort to save energy.” This made me decide that everyone should be made aware that it is simple & cheap to make a cooker themselves instead of waiting for a factory built one. Working on free, clean, abundant energy it saves money, fossil fuel & the environment. In fact it could help avoid the confusion I see daily at the LPG dealer near my house!

Some important facts about solar cooking:

Room temperature - 27°C Most germs die - 49°C Water pasteurisation - 65°C Food pasteurization - 71°C Food cooks - 82°C Water boils - 100°C The normal internal temperature range in a solar box cooker is 82°C - 135°C

It saves time & money - A solar cooker is cheap to make & works on free sunshine. Dishes are easy to clean as food does not stick or get burned. Food cooks unattended while you do other work. It is safe & healthy - There is no danger from fire or smoke to irritate your eyes. Food is cooked at 82ºC - 121ºC which is ideal for retaining nutrition and flavour. Food, water & surgical instruments can be pasteurized even in emergency situations. It saves trees & soil - Where people have no alternative to wood fueled cooking, efforts to protect trees fail. Soil erosion & low rainfall quickly follow and farmers can no longer use the land for crops. In sunny climates solar cooking can save one ton of wood per year per household!

It solves three of the world’s most pressing problems: Scarce, expensive fuel - according to the United Nations, people in some countries spend 30-50% of income on cooking fuel & 1/3 of the world population suffers acute fuel shortage. Water borne diseases - according to the World Health Organisation waterborne diseases kill 50,000 people per day worldwide as 80% of illnesses are spread through contaminated water. Pollution - smoke & toxic gasses are released while burning fossil fuels leading to global warming.

India, Africa and China are the world’s leading users of parabolic & box cookers. Box cookers are most popular as multiple dishes can be cooked together, water pasteurized and instruments sterilized. Solar cookers cook food slowly ensuring more nutritious food. Regular use can save each household 3 to 4 LPG cylinders per year.



About 525,000 Indian homes use solar cookers, second largest number in Asia. The Ministry of Non-Conventional Energy Sources established in 1982 promotes solar cookers by offering subsidies. The world’s largest solar cooking systems are installed at Tirumala, Tirupathi and Saibaba Ashram at Shirdi in Maharashtra. 73 parabolic dishes use sun-rays to generate steam to cook for 50,000 devotees daily saving nearly 100,000 kg of cooking gas annually. Linked to boilers, it works for some time even without sunlight. The temple reduces carbon dioxide emissions by 1.2 tonnes per day and sells its emission reduction credits earning the shrine Rs. 17 lakh a year.

Joshua Jude Vaz,

Donvaddo, Saligao.