Building a Solar Oven in Costa Rica

Posted: April 24, 2012

Name: Ana Contessa Aguilar
Position: Intern
Program: Sustainable Development Studies, Costa Rica
SFS Alum: Costa Rica Summer ’11

 

Sun is the main source of energy for Earth, and here in Atenas, during the dry season, we are lucky to have it shining strong and bright every day. The problem is, like in lot of other places around the world, we do not take advantage of such a resource. People use fuels or wood to produce the energy they need, which leads to several environmental problems, but there is a simple answer to help ease some of these problems. Following the Center’s sustainable development theme and goals, we decided to take advantage of this valuable resource and build a solar oven and dryer.

 

 

 

 

 

 

 

The use of solar ovens and dryers can be found throughout the world, especially in the tropics where sun availability is most abundant. A search on the Internet can lead you to many designs; however, in our case, protection from insects was something that had to be seriously taken into consideration for our design in order to preserve the food. Most of the designs were open structures or had open areas that would allow air to circulate through them – if we decided on one of these, our food, especially fruit, would probably be covered with ants in less than a minute.

I decided to build a structure that would be totally closed.  It would have glass which would allow the sunlight to go through, and at the same time protect the food from insects.  As I looked through the designs, I also thought about the amount of space we would need to cook or dry food. We wanted both processes (cooking and drying food) to take place at the same time, and we also wanted to use our materials in the most efficient way.  Therefore, I decided to build both an oven and dryer in the same structure. Half of it would cook the food; the other half would dry the fruit.

Building the oven/dryer was a fun and exciting learning process. Working with Guillermo, one of our farm staff members, I learned to determine which materials would work the best as well as how to work and cut wood and metal. First we built a wooden structure with plywood and then, covered the inside with zinc sheets which capture the heat.  After building the structure, we painted it with black paint in order to increase its ability to capture and retain heat, thus increasing the temperature of the oven.

Unfortunately, our students (busy bees) were not able to be part of this process due to their busy schedules.  Fortunately, now that the oven is finished they have learned to use it, and they get to enjoy the delicious dry fruit.  They are also involved in deciding what new fruit we can try to dry. Some of the fruits we have dried are: bananas, ripe plantains, pineapple, and green mango.  The drying of the food usually takes a day and a half, but the end product lasts less than a day! The students love the dry food and eat it non-stop!