Project data

Parabolic solar cookers are designed to utilize the sun's vast supply of energy to do what we all need to do from time to time, cook food! Instead of cranking up the gas oven or turning on an electric stove, we can harness the sun's energy to focus light to generate enough heat to make food, or even distill water.

This project was originally inspired by Bart Orlando in Spring of 2018, for a class project in Appropiate Technology Course at Cal Poly Humboldt.

## Problem statement

The objective of this project was to make a solar cooker with Bart Orlando as the client. The idea of solar cookers has been around for quite some time now. One of the biggest appeals of solar cookers is that there are no indoor air quality health effects associated with the use of them. This appeal has inspired people like Bart Orlando to try to to produce solar cookers at a scale that could be implemented into developing countries to combat carbon intensive wood burning cook stoves and other cooking methods that produce greenhouse gases as a by product.

## Project Evaluation Criteria

The following Criteria will be used to assess the success of this project. These criteria were chosen based on the suggestions of the project coordinator as well as the diligent students who are working on the catchment system. The scale (1-10) represents the importance level of meeting the constraint of each listed criteria.

Criteria Constraints Weight (1-10)
Safety Must be located in an area that makes it so that has no potential fire hazard. Must be equipped with adequate protective gear such as sunglasses, gloves and a tarp. 10
Maintainability Must be easy to clean and have adequate supplies to prevent scratching of the mirrors. 4
Aesthetics Must be pleasing to the eye and look professional 4
Storability Must have the option to break down the solar cooker in order to be able to store the solar cooker in a reasonably small area. 7
Efficiency Must be able to boil water on a completely sunny day and also light a 2 by 4 beam on fire. 10
Usability Must be able to give brief instructions on how to use the solar cooker. 7
Portability Must be able to fit in the back of a the average sized pickup truck. 8
Cost Must not exceed budget 9

## Literature Review

This is a review of the available literature pertinent to the a specific project.

### Solar Cooker Basics

The more reflective the material used for a solar cooker's surface, the more energy from the sun will be converted directly to the focal point to generate heat. True mirrors have the highest potential of converting light into heat. Reflective aluminum is another great material to use that will be about 95% efficient. However, the material is only one aspect of the cooker. Forming the correct shape so that all the energy is directed to one point is an essential aspect of the solar cooker.

### Parabolas and Paraboloids

The three dimensional parabola, the paraboloid, is the most efficient shape for solar cookers. Unlike box solar ovens, the parabolic shape has a central focal point where any light that hits the parabola’s walls will reflect into it. Using sunlight, the heat, along with the light, will reflect into that focal point and warm that spot. The cooking container should be located at the focal point so the maximum amount of heat will be used for cooking. With the general equation for a parabola being:

${\displaystyle y=x^{2}}$

the focal point can be found by taking a point on the curve, (x, y) and putting it into the equation:

${\displaystyle a=x^{2}/4y}$

with the variable, a as the focus (Stein, 1999).[1]

### Humboldt County Weather

The amount of clear days in Humboldt County is the major inconvenience with local solar cooking. Arcata has around 78 completely clear days per year with the most during September and October and a monthly average of 6.5 clear days (Western Regional Climate Center). Although most days are not completely clear, there are still partly cloudy days where it will clear up long enough to cook something around midday to early afternoon. This inconvenience of weather in Humboldt County became one of our projects largest obstacles. [2]

## Project goals

Describe project goals here.

To make a numbered list use the pound sign:

1. Build solar cooker
2. Stay within budget
3. Boil 1 liter of water

## Design

### Materials and Tools

 4 ft in diameter old aluminum satellite dish 3 sheets of 2ft by 4ft reflective aluminum sheet metal Cast iron pot 80 bolts and nuts 3 10ft wood poles 50ft of 550 cord Guitar stand 2 sawhorses Angle grinder 2 drills with metal drill bits Chisel File Protective eye gear Dust mask Gloves ear plugs Close toed shoes

## Budget

This budget is an estimation of the monetary costs anticipated in the construction of a parabolic solar cooker.

Quantity Material Source Cost (\$) Total (\$)
3 2x4 Mirrored Aluminum Sheets Lonny Donation Free
1 Box of 100 1/2" Hex Bolts Ace Hardware 10.00 10.00
1 Box of 100 1/2" Hex Nuts Ace Hardware 8.00 8.00
1 Box of Aluminum Foil Safeway 3.25 3.25
1 Cast Iron Cook Pot Clay's Garage Donation Free
1 Guitar Stand Jay's Place Donation Free
1 Butcher Paper Engineering Lab Donation Free
1 4' Satellite Dish Arcata Scrap Yard 60.00 60.00
Total Cost \$81.25

## Conclusions

From an appropriate technology stance, solar cookers are not very ideal for the Pacific Northwest Region. The reason for this is that the amount of sunlight in a given day is typically very limited as it is generally mostly overcast. This exactly happened when we tested our solar cooker. We tested the cooker at 1:00pm on May 6, 2018 with it being sixty degrees and partly cloudy. Once we put our liter of water we were testing with into the cast iron pot we were able to get the water to 123.5 degrees Fahrenheit. This was only a couple of minutes into our testing when the sun we had over head in the sky became covered up by heavy cloud coverage. Cloud coverage like we experienced when testing with our solar cooker impedes the ability for solar energy in the form of sunlight to reach the solar cooker and generate enough heat to boil water.

## Next steps

• Further develop stand design and cast iron pot holder.
• Expand testing data by cooking different foods in climatically diverse conditions.
• Find a home for the solar cooker or deliver to Bart Orlando.

## References

1. “Parabolic Basket and Tin Can Solar Cooker.” Conventional Farming - Appropedia: The Sustainability Wiki, ENGR 305 , 23 June 2017, www.appropedia.org/Parabolic_basket_and_tin_can_solar_cooker..
2. “Parabolic Basket and Tin Can Solar Cooker.” Conventional Farming - Appropedia: The Sustainability Wiki, ENGR 305 , 23 June 2017, www.appropedia.org/Parabolic_basket_and_tin_can_solar_cooker..

## Contact details

• Jay Nutt - jcn5@humboldt.edu
• Clay Smeback - wcs62@humboldt.edu
• Roger Hess - rwh202@humboldt.edu
Page data
Type Project mirrored aluminum sheets, guitar stand, satellite dish SDG09 Industry innovation and infrastructure 2018 CC-BY-SA-3.0 English (en) 325 "Bart parabolic solar cooker 2018". Appropedia. 2018. Retrieved December 9, 2022.
Cookies help us deliver our services. By using our services, you agree to our use of cookies.