Solar Cooker


Group Members:

Jose Samperio
2nd year business administration major concentrating in finance and accounting. I currently own and operate a local longboarding business in SLO. I also like to play the piano, stay active, and explore new places.

Neel Kogali
2nd year mechanical engineering major

Gabe Pregadio
5th year general engineering major

Katie Sones
2nd year Graphic Communication major and Media Arts, Society, and Technology minor. I’m the secretary of the Film Production Society, and interested in music, history, typography, calligraphy, and industrial design.

Ebrahim Feghhi
1st Year Physics major. I’m currently involved with the Cal Poly Entrepreneurship Club and interested in Online Education. I enjoy doing Jiu Jitsu and reading books.

The Problem: The Smithsonian has stated that “some 3 billion people use rudimentary stoves that burn wood, dried dung, or coal”. Kirk Smith, a professor of global environmental health at UC Berkeley, concluded that having an open fire in your kitchen is equivalent to burning 400 cigarettes per hour (

That is a scary statistic. Our group firmly believes that everyone should have access to a clean way to cook their meals.

Our Goal: For this project, our group hopes to gain a deeper understanding of the solutions available for cleaner cooking. Specifically, we would like to focus on solar cookers that concentrate sunlight. We will be remaking Ian Davison’s solar cooker in the hopes of improving it.

Through this process we hope to gain a deeper understanding of how solar cookers work and how feasible they are for people to use them.

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January 26, 2016:

  • We are currently exploring our options to determine what insulating materials to use
  • We are also researching solar concentrators to figure out the flaws and successes of prior designs


  • Our solar concentrator is going to be based on this prior design
  • We want to make ours more efficient

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  • The heliostat uses two photoresistors and a comparator hooked up to a motor that turns the mirror based on the sun’s position throughout the day. The heliostat’s mirror reflects sunlight onto the parabolic concentrator, which concentrates the sunlight into a more direct beam at the focus of the parabola, and reflects it to the spot where we have set up the pot. The concentrated sunlight heats the pot for cooking.

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  • Because our main goal is to cook, heating the pot is of utmost importance. To make sure as much of the light from the concentrator gets to the pot as possible, we’re adding more insulation around the pot itself. Although we’re using bent cardboard and aluminum foil for our prototype, we will most likely replace this with something sturdier.

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February 10, 2016:

  • We dug a hole to position our half parabola tool
  • We then positioned our tool at 35.3 degrees using cinder blocks.
    • We used this angle because it is parallel to the earth’s axis, and the rotational axis of the heliostat must be parallel to the earth’s axis to properly reflect the right amount of sunlight. With the sunlight being reflected at that angle, the paraboloid used to make the shape of the concentrator must be positioned at the same angle to collect the heliostat’s reflected sunlight.
  • Finished lab by outlining the hole with cob


February 15, 2016:

  • Tragedy has struck – night winds blew the solar reflector,
  • The moment was placed on two bolts that were spaced less than five inches apart
  • This resulted in significant damage to the mirror and the wooden base.
  • Change in direction for our project – now focusing on support for the heliostat.



February 23, 2016

  • Constructed a new base for the heliostat, later to be attached to the green pole
  • Plan to implement a long steel pole and rectangular wooden piece along base for additional support
  • The wooden structure below will be buried under the dirt.


February 23, 2016:

  • Katie drills holes into a rectangular wooden piece
  • She wants to attach this to the base to add support


February 26, 2016:

  • Focusing on building strong enough base to hold up mirror
  • We await our first test run in boiling water!

March 1, 2016:

  • Our team captain, Katie, showing of her prowess after digging the hole for the base of the heliostat.


Ian explains the circuit to us. We bought comparators, a relay, and various cables for it to work properly.

  • After we re-assembled the heliostat, we put the mirror back on the ground to prevent further damage


March 8, 2016:

  • Using a compass, we made sure that the heliostat was facing the right direction since this is vital to the success of the mirror.


March 9, 2016:

  • doing some more digging to bury the heliostat!


March 10, 2016:

  • In order to ensure we installed everything properly, we met up with Ian one more time. Ian gave us great tips!
  • After this, our mirror reflected light successfully onto the concentrator.
  • The mirror survived heavy rain because of the newly implemented base.


We learned a lot about how solar cookers work throughout this process. In trying to install this technology, we got new knowledge on how the various aspects of this solar cooker works. We were good test subjects for the usability of the solar cooker as we had no prior knowledge of how it worked. Trying to install and use the solar cooker resulted in us breaking it and having to put it back together. The solar cooker broke because it fell down in the wind, so we decided to add support to the base in the form of a 2-by-4 and piece of metal pipe perpendicular to the face of the heliostat’s mirror. With these added to the bottom, the heliostat doesn’t have to be buried as deep and is more resistant to wind. This is helpful because we learned that digging a deep hole might not always be easy depending on what kind of soil there is, and high-speed winds have the potential to completely take out the solar cooker, which would mean no cooking until it’s fixed. Fixing the mirror may not be an easy process for everyone. The added supports make the solar cooker easier to maintain. We also added reflective material around the stand for the pot to insulate it and keep light from escaping. Overall, we believe this solar cooker is a great idea. However, we also believe that it would not be very sustainable in a third world country. Although it successfully captures sunlight to cook food, it is much to big, expensive and complex for a 3rd world country to successfully implement into their society.