Explain the principles and working of solar cooker. Also highlight its features over conventional cooker.

A solar cooker harnesses the energy of sunlight to cook food without the need for conventional fuels such as gas or electricity. The principle of a solar cooker is based on the conversion of solar radiation into heat energy, which is then used for cooking. Here's how a solar cooker works:

Principle:

1. Solar Concentration: Solar cookers utilize reflective surfaces or concentrators to focus sunlight onto a cooking vessel or cooking area. These concentrators may consist of reflective panels, mirrors, or parabolic troughs, which redirect and concentrate sunlight onto the cooking surface.

2. Absorption of Solar Energy: The cooking vessel or cooking area absorbs the concentrated solar energy, converting it into heat. The material of the vessel or cooking surface should be dark and opaque to maximize absorption of solar radiation.

3. Heat Transfer: Once absorbed, the solar energy heats the cooking vessel and the food inside through conduction. The trapped heat gradually raises the temperature inside the cooking vessel, allowing food to cook over time.

Working:

1. Preparation: Food is prepared and placed inside a cooking vessel, such as a pot or tray, along with any required seasonings or ingredients.

2. Placement: The cooking vessel is then placed inside the solar cooker, which is positioned in direct sunlight. The cooker is adjusted or oriented to maximize exposure to sunlight throughout the day.

3. Solar Cooking: As sunlight strikes the reflective surfaces or concentrators, it is focused onto the cooking vessel, generating heat. The trapped heat cooks the food inside the vessel at temperatures sufficient for boiling, steaming, or slow cooking, depending on the design of the solar cooker and the cooking duration.

4. Monitoring: Solar cooking typically requires longer cooking times compared to conventional methods, so periodic monitoring may be necessary to ensure that food is cooked evenly and to the desired level of doneness.

Features over Conventional Cookers:

1. Environmentally Friendly: Solar cookers use renewable solar energy, reducing reliance on non-renewable fuels and minimizing greenhouse gas emissions associated with conventional cooking methods.

2. Cost Savings: Solar cookers eliminate the need for purchasing fuel, such as gas, charcoal, or electricity, resulting in long-term cost savings for users, especially in regions where fuel costs are high or access to conventional energy sources is limited.

3. Health Benefits: Solar cooking eliminates exposure to indoor air pollution from burning solid fuels, which can cause respiratory illnesses and other health problems, particularly in households without proper ventilation.

4. Safety: Solar cookers operate without open flames or hot surfaces, reducing the risk of burns, fires, and accidents associated with conventional cooking methods.

5. Suitability for Off-Grid Areas: Solar cookers are ideal for off-grid or remote areas with limited access to electricity or gas infrastructure, providing a sustainable and reliable cooking solution for communities in rural or developing regions.

Overall, solar cookers offer a clean, sustainable, and cost-effective alternative to conventional cooking methods, making them valuable tools for promoting energy access, environmental sustainability, and public health worldwide.