Abstract
The goal is to create an efficient way for cooking using photovoltaics and thermal treatment. The examples have been limited since there has been so much focus on using a solar concentrator cook stoves and improved combustion stoves like the rocket stoves we learned about in class.
This new technology has been summarized in the examples presented below.
Our goal is to create an efficient way of cooking using photovoltaics and insulation in order to eliminate the smoke in houses that is caused from indoor cooking. We strive to design a solar cooker that will be effective at accommodating the “boil and simmer” method of cooking practiced in developing countries such as boiling water to cook meals. This provides a familiar way to cook, so people will be more willing to use the solar cooker since it is not a change in habit.
Through researching previous quarters in UNIV 392, Aid Africa and other examples of solar cooking in Ghana and Uganda, we were able to design a solar cooker that is able to cook raw dried beans and lentils in under 3 hours.
Sources
(1) http://www.hindawi.com/journals/isrn/2013/746189/
(2) **Collaborative Development of Ultra Efficient Photovoltaic Solar Cooking:** Supplementary Information
Context
We are using a 100W photovoltaic panel to heat a 14 ohm burner modified to 3.8 ohms, so that we can receive a maximum power transfer. We had the options of either reducing the amount of resistance by a fourth from the burner or we could add three burners to satisfy the amount of power that we have from the 100 watt solar panel. We decided that the best way was to reduce the resistance. To do this we needed to actually cut the heating element in half.
Surrounding the burner, we have cob covering the hay. The cob has a dual purpose; it keeps loose straw from the hay bale from falling onto the burner as well as insulating the surrounding hay to keep if from catching fire if the burner gets too hot for some reason.
We attached a Arduino controls in order to control the temperature and turn the burner off once it reaches a certain temperature. The extra power generated from the solar panel will connect to a 5 volt battery in order to be able to connect to a USB cable where one can charge a phone or device.
Other Publications
From the research done by Smita B. Joshi and A.R. Jani we have the following information to apply to our design:
The Photo-Thermo solar cooker is a photovoltaic and thermal hybridized solar cooker. It is connected to a 12 volt 40 ampere-hour battery. This battery will be charged by a solar panel of 75 watt. To decide the minimum requirement of wattage for cooking, we operated the cooker with a power supply.
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There has also been an experiment done in the
Summer of 2015
from Cal Poly on the same type of technology. This is their experimental trial:
Experimental Trial:
As a proof of concept, we cooked ~ 2 kg chicken with ~ 1.6 kg of vegetables in a 5-gallon prototype using a 100 W heating element. As seen in figure 4, Poultry’s minimum safe internal temperature of 74°C (165°F) was reached in about 2 hours. After 5 hours, the chicken’s internal temperature was over 100 °C and the air temperature inside the steel drum was 111°C (232°F). The chicken was thoroughly cooked, as were the vegetables inside the chicken. The theoretical time necessary to heat 3.6 kg of water from 20.5°C to 100°C is almost 3 hours 20 min, roughly consistent with our experimental results allowing for some heat loss through conduction and boiling.
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We found the the time it took for this experiment to take place was much longer than we expect our audience to use. Using this data, hopefully we can brainstorm ways to make the cooking time faster and more efficient.
Materials Needed
HEATING SYSTEM
Hay Bales [4]
Pot
Cob [Sand | Clay | Straw]
Electric Burner [1]
PV SYSTEM
100 watt PV Panel [1]
10 AMG Wire
Signal Wire [3ft]
TEMPERATURE CONTROL
Arduino [1]
Thermal Couple [1]
On/Off Switch [1]
SunPath Research
<http://www.sunearthtools.com/dp/tools/pos_sun.php>
Based off this information and the fact that our panel is 26″ long, we need to place our panel at a max height of 21″ at 12:00pm order to have maximum sunlight hitting the solar panel.
Straw Bale Insulation
https://en.wikibooks.org/wiki/Straw_Bale_Construction/Characteristics/Insulation
Videos
GoSun has a portable solar cooker that we are aspiring to achieve eventually in future renditions. This would also be more relevant in affluent markets. GoSun is made from high quality materials using modern manufacturing techniques. Our solar cooker does the opposite, utilizing the materials we had available to us and the combined expertise of five undergraduate college students. One of the biggest things that we do differently is use extensive insulation. We do not draw enough power from our small solar panel to get the heating element very hot or raise the temperature very quickly, so minimizing heat loss to the atmosphere is of the utmost importance.
http://www.gosunstove.com/