Solar cookers are a renewable and sustainable technology that utilizes the sun’s energy for cooking food without any electricity or fuel. This article provides a comprehensive overview of solar cooker working, types, benefits, costs, usage tips and the future outlook of this green cooking solution.
How Do Solar Cookers Work?
A solar cooker basically consists of an insulated box with a reflective lid or mirror that focuses sunlight into the box. The box converts sunlight into heat energy that cooks the food inside.
Some key principles:
- The insulated box minimizes heat loss
- Reflectors concentrate solar radiation through refraction
- Dark surfaces inside absorb and retain heat
- Transparent glass/plastic allow light in but trap heat
- Food cooks from the trapped solar heat
As long as sunlight is available, a solar cooker can generate temperatures of 150°C to 300°C to cook, bake or pasteurize food. No fuels or electricity required!
Types of Solar Cooker Designs
There are 3 main types of solar cooker designs:
This is the most common and simple design. It consists of an insulated wooden or cardboard box with a glass or plastic lid. Inside is a dark tray to absorb heat. Reflectors are placed around to concentrate sunlight into the box.
It has a similar working but uses reflective panels to direct sunlight towards a cooking pot rather than an insulated box. The pot is placed in a glass-covered chamber or can be suspended above reflectors.
It uses a parabolic dish reflector that focuses sunlight along a focal point. The cooking pot is placed at this point above the dish where concentrated solar energy heats it up rapidly.
Benefits of Using Solar Cookers
Solar cookers offer several benefits that make them an attractive sustainable cooking option:
- Zero emissions – Does not produce any greenhouse gases or smoke
- Renewable – Uses endless free energy from the sun
- Fuel/electricity savings – No costs for LPG, biogas or electricity for cooking
- Low maintenance – Very few moving parts and minimal operating costs
- Safety – No risks associated with open flames, gas cylinders, indoor air pollution etc.
- Portability – Compact cookers can be easily moved and require only sunlight to function
- Empowerment – Provides energy access for cooking without dependence on fuels
Cost of Buying a Solar Cooker in India
The cost of solar cookers in India varies from ₹1,500 for a small box-type cooker to ₹15,000 for a larger parabolic cooker.
- Basic box cooker – ₹1500 to ₹3000
- Foldable suitcase cooker – ₹3000 to ₹5000
- Panel cookers with pots – ₹4000 to ₹7000
- Large parabolic cookers – ₹10,000 to ₹15,000
Govt. subsidies under MNRE schemes provide up to 30% discount on solar cooker purchases.
Tips for Effective Use of Solar Cookers
Here are some usage tips to cook food efficiently using solar cookers:
- Place cooker in direct sunlight and angle reflector towards sun
- Preheat for 30 minutes prior to cooking
- Cut food into smaller pieces to cook faster
- Use dark, shallow vessels with tight lids
- Avoid opening lids frequently
- Cook in batches for larger quantities
- Soak grains, pulses overnight for faster cooking
- Track peak sunshine hours for maximum heat
- Use backup cooking if sunlight is inadequate
Limitations and Challenges
Despite the benefits, solar cooker use has some limitations:
- Dependent on sunny weather
- Slow cooking times
- Difficulty cooking for large groups
- Limited to heating, roasting, baking only
- Need backup cooker on cloudy days
- Not feasible for evening cooking
- Higher cost compared to stoves
Ongoing innovations to improve efficiency and convenience will help overcome these challenges.
Future Outlook and Trends
Here are some emerging trends that will shape future adoption of solar cookers:
- Use of phase change materials to extend cooking after sunset
- Hybrid cookers with electric/biogas backup heating
- Use of heat pipes, vacuum tubes to increase heat retention
- Lightweight portable designs
- IoT integration for remote monitoring and control
- Community solar cooker installations
- Pay-as-you-go business models for rural usage
- Government promotions and carbon credits to drive uptake
Solar cooking holds enormous potential as a clean cooking solution for remote, rural households as well as urban households looking to save on LPG costs and emissions. Their use is poised to grow manifold over the next decade if product improvements continue and awareness spreads.
Solar cookers provide a zero-emissions, renewable method of cooking powered by the sun. Although relatively high upfront cost and dependence on weather remain barriers, solar cooking offers benefits like fuel/electricity savings, safety, empowerment and sustainability. Advancements and government support are expanding global adoption. For households seeking a green cooking solution, solar cookers present a promising option.
top 10 frequently asked questions about solar cookers
1. What are the different types of solar cookers available?
The main types of solar cookers are box cooker, panel cooker and parabolic cooker. Box cookers use an insulated box with reflectors, panel cookers use reflective panels, and parabolic cookers use a dish reflector.
2. How much does a solar cooker cost in India?
Basic solar cookers cost between ₹1,500 to ₹3,000 in India. Higher end models like parabolic cookers can cost ₹10,000 to ₹15,000. There are also mid-range options like panel and foldable suitcase cookers priced from ₹4,000 to ₹7,000.
3. What can you cook in a solar cooker?
Solar cookers can be used for cooking rice, dal, vegetables, eggs, baking cakes, roasting nuts, steaming idlis etc. Foods that require deep frying cannot be prepared.
4. How long does solar cooking take?
Cooking in a solar cooker takes 1.5 to 2 times longer than traditional stoves. Foods cook slower in the 200°C to 300°C temperature range. Pre-soaking grains and pulses reduces cooking time.
5. Can solar cookers work in cloudy weather?
Solar cookers work best in direct sunlight. Cookers will work on cloudy days but at lower temperatures resulting in very slow cooking. Back-up cooking options should be planned for cloudy periods.
6. Are solar cookers safe to use?
Yes, solar cookers are very safe to use since there is no open flame or risk of burns. The box and pots remain cool from outside allowing safe handling.
7. What are the benefits of using a solar cooker?
Benefits include zero emissions, no fuel costs, portability, safety, empowerment and sustainability. Solar cooking reduces indoor air pollution and saves on LPG expenses.
8. Do solar cookers require maintenance?
Solar cookers require very minimal maintenance except occasional cleaning of the glass and reflector. They have no recurring costs unlike LPG cylinders.
9. Can solar cooking be done in the evening?
No, solar cooking is only possible when direct sunlight is available and is not feasible in the evenings after sunset. Backup cooking options should be planned for evening meals.
10. Are there government subsidies available for solar cookers in India?
Yes, MNRE provides a 30% subsidy on the purchase of solar cookers under its National Programme on Solar Cookers.