The design factor is one of the most important criteria for the solar funnel. Generally Line Concentrated Solar Cooker does not require any tracking mechanism. In order to prevent tracking mechanism in solar funnel, the design is in such a manner that the maximum sunrays are impinging on the reflecting surface of the Line Concentrated Solar Cooker all the time. This line concentrated solar cooker has been designed in such a way that minimum of at least 35 percent of the area of the cooker is exposed to the sunlight by 8:00 AM and maximum by 100 percentage by noon. The design based on this criterion gave us a good result leading to heating effect from morning to evening. As the time goes on increasing the area covered on
the Line Concentrated Solar Cooker by the sunlight increases up to afternoon. As the sun sets the area covered on the cooker, by the sunlight starts to decrease thus decreasing the effect of the cooker by evening. It has been calculated that for a family of four members, at least half meter square of area (minimum of 35% area of the cooker) has to be exposed to the sunlight all the time. That is starting from 8:00 AM to 4:00 PM. Hence a Solar Cooker was designed with the total area of 1.66 square meter out of which 0.585 square meter area will be exposed to the sunlight by 8:00 AM and gradually increasing by noon. The top diameter, bottom diameter, height of the Solar Cooker was found to be 138 cm, 43 cm, and 33 cm respectively. In order to find the area exposed to the sunlight at different times, the following data like latitude, longitude, declination, hour angle, altitude angle and incident angle were calculated for each hour for concern latitude and longitude. For the geological location where the experiment is to be conducted, the latitude and longitude were found to be 10.8 0 north and 78.28 0 east respectively. The declination angle was found as 5 = 11.403 0. The corresponding Altitude angle, Hour angle, Incident angle for different time period were calculated and tabulated as follows:

From the above tabulation, it can be found that the altitude angle goes on increasing from morning 8:00 AM to noon and then decreases. Similarly, the incident angle of the solar rays on the solar cooker decreases up to noon and then increases. This ultimately indicates that concentration of the sunlight is increasing until noon and then decreasing. The following table shows the percentage of area exposed to the sun at various time starting from morning 8:00AM to evening 5:00PM.

This area of exposure to the sun was determined theoretically. But in order to prove that the values which got theoretically as calculated above is correct, the area exposure to the sun was determined practically by keeping the Line Concentrated Solar Cooker exposed to the sun. On conducting this experiment, the values correlated with the actual theoretical values approximately. The values got on conducting practical experiment is as follows:

When the above two graph were merged together, all the points from both the graph were fitting to the curve approximately.

The solar cooker with the above dimensions looks as follows:

43 cm

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