Clean alternatives to firewood cooking stoves | Sunday Observer

Clean alternatives to firewood cooking stoves

11 November, 2018
Cookers on display
Cookers on display

Most people are shocked to discover the dangers associated with cooking with firewood and the number of deaths attributed to this.

Seggy Segaran, a Sri Lankan born engineer and business owner who has resided in the UK for the past 40 years has researched and designed a cooker which, he hopes will replace the firewood cooking stove.

“My wife and I have been experimenting with Solar and Haybox cookers over the past few years with the intention of spreading their use in Sri Lanka and other countries.

These cookers reduce the use of firewood or LPG gas thus saving money for the users and bypassing increases in the price of fuel. If firewood is being used then the use of these cookers will reduce smoke inhalation and resulting harm to health, as well as reduce deforestation,” he said.

“Solar and Haybox cookers are being manufactured in Moratuwa by the Emace Foundation for distribution to low income families. Solar cookers use the power of the sun to cook food directly. The heat from the sun is trapped in an insulated box behind a sheet of glass. Additional reflectors can be used to collect heat from a larger area. The food is cooked in a black pot which converts the radiated energy from the sun into heat. A black metal sheet at the base of the cooker is used to retain the heat,” Segaran said.

He further explained that a Haybox Cooker is basically an insulated box in which you place your partly cooked food. “The heat energy held in the pot and the food completes the cooking process without any external heat input. Haybox cookers are so called because the early versions used hay as insulation. It is also referred to as fireless cooking or retained heat cooking. Various forms of Haybox cookers are used widely in the developing world to cut down on the use of firewood. This saves the time spent in gathering fuel and helps reduce deforestation. Conservative estimates of fuel saving vary from 30 – 50 %,” he said.

Solar cookers and Haybox cookers can be used instead of a firewood cook stove, to achieve a clean cooking target and minimise Indoor Air Pollution (IAP). “This was a by-product of our research into ‘low impact cooking’. My wife Jane and I have been researching cooking techniques that use less energy and less wood, to help reduce de-forestation and we found out about the impact of cooking smoke on people’s health. This is a priority area for the UN as well. It is also of concern to the Bill & Melinda Gates Foundation,” says Segaran.

Explaining the benefits of Solar and Haybox cookers, he said that these techniques have been around for many decades. “It helps reduce IAP, deforestation and saves money. What we have done is build prototypes we cooked with these to find out more about them and to build them cheaply. We have been doing this since 2013. Solar cookers can be used during the dry season and are very good for cooking rice, potatoes and eggs.

People may also need to use firewood for their other curries and to make rotti or fry, but less of it. Haybox cookers can be used all year round. You still need to cook the food but for only half the time that you would normally need. So both of these cookers allow the person cooking to use less wood, and produce less smoke,” he said. “The EMACE Foundation, Moratuwa has built solar cookers before and introduced them.

This is a small scale grass roots venture. This means we can move very fast. When too many people are involved it is difficult to make quick decisions. The EMACE Foundation already has experience in Solar Cooking. We introduced the concept of Haybox Cookers and provided some funding to build each type locally in Sri Lanka. These have been built and EMACE are just starting the process of distributing them,” Segaran said.

Segaran said that the Government organisations are sometimes hampered by bureaucracy and react very slowly. “Often people wait for solutions from the government when there is much that can be done by individuals. The media could help a lot in publicising this issue of harmful cooking and promoting solutions directly to the people without waiting for government action. I would like to promote the use of Solar Cookers and Haybox Cookers in Sri Lanka.

We can also publish designs so that they can be built locally. I would also like to link up with suitable organisations in Sri Lanka that would help me with this project,” he added. “There are many benefits of cooking by using the power of the sun. Conventional cooking requires the use of fossil fuels such as wood, charcoal or kerosene. As well as costing money this depletes the Earth’s natural resources as well as adding to pollution and greenhouse gases. Solar cooking is free, and does not produce any pollution.

With Solar cooking one does not have to stand over the saucepan constantly stirring and making sure that the food does not burn. Once the food is prepared and is cooking, you can leave it until it is cooked, giving yourself more free time. Less water is used with solar cooking and more nutrients are retained as everything is cooked in a closed container at a lower temperature. Cooking over a fire can lead to health problems due to inhalation of smoke. There is no risk of this with solar cooking,” he said.

Segaran said that there are different types of solar cookers in use such as Box cooker, Parabolic cooker and panel cooker. “A box cooker is simply a well insulated box with a glass cover. The glass allows solar radiation in but does not allow the reflected radiation out - thus trapping heat in the box. With time, the temperature inside the box increases to more than 100 deg C (Celsius(C) allowing one to cook food inside. These are easy to make but will take a longer time to cook the food,” he said.

“The Parabolic cooker uses a parabola shaped reflector to concentrate the sun on to a small area, thus reaching temperatures of more than 200 deg C. Whereas the Box and Panel Cookers work like an oven, the Parabolic cookers allow “top of the stove” dishes to be prepared. However, they do need aligning to the sun every few minutes to maintain the temperature.

Panel cookers use elements from the Box and Parabolic cooker. The reflectors concentrate the suns radiation on to a small area like the Parabolic Cooker but do not have to be realigned every few minutes. Instead of an insulated box an oven roasting bag is used to trap the heat around a black cooking pot. Panel Cookers are extremely cheap to make but only work well in tropical climates,” he said.


Using the Solar Box Cooker

This design of Solar Cooker works like an oven. This will require a change of habit when one is accustomed to cooking on a fire. However, the time and money saved in buying firewood or kerosene will make this worthwhile.

The Solar Box Cooker is great for cooking a meal of Rice and Lentils. Here is a step by step guide to preparing a simple lunchtime meal for two to three people.

1. Soak a cup of lentils in water overnight.

2. Around 9 a.m. place the cooker in the sun with an oven thermometer inside. Assemble the reflector panels (2 or 4 as required) and make sure the door is closed. Leave the oven to warm up. (We need the oven to reach a temperature of more than 100 degrees C before we can start cooking).

3. Start preparing the food around 10 a.m. Take an onion, a few tomatoes and a sweet pepper. Chop finely and put in a black pan. Add a few cloves of garlic, salt and turmeric for flavour. Drain the water from the lentils and add to the pan and add half a cup of water. Mix well.

4. Wait till the oven has reached a temperature of more than 100 deg C. Put a lid on the saucepan and place in the oven.

5. Wash a cup of rice thoroughly and add to a black pan and add a cup of water. Cooking in a Solar Oven needs less water than when cooking on a fire.

6. Put a lid on the saucepan and place alongside the lentils.

7. After about an hour and a half both rice and lentils should be perfectly cooked and ready to eat.