CETC-Ottawa Promoting Innovative Solar Energy Technology for Energy Savings in Crop Drying

A Costa Rica solar coffee-drying project at Coopeldos R.L. in Tilaran is the latest project to make use of innovative Solarwall® technology, which was developed with support from Natural Resources Canada (NRCan). The installation of this new solar thermal system to dry coffee is the largest of its kind in Central America.

The project involved the installation of 850 m² of Solarwall® panels on the roof of the Tilaran plant. Intake fans draw in warmed air from perforated panels to dry the coffee beans. The Solarwall® technology is 40% more efficient and cost 25% less than conventional solar products.

The key to this particular type of collector is an industrial-grade siding/cladding that is perforated with many small holes at a pitch of 2-4 cm. Air passes through the holes in the collector, picking up heat before it is drawn into the furnace to provide preheated air to the dryer. Efficiencies are typically high because the collector operates close to the outside air temperature.

The Tilaran site is one of six test sites (others in Panama, China and India) that will reduce CO₂ emissions by 1,000 tonnes a year by displacing fossil fuels. Other benefits to coffee producers include saving energy and reducing deforestation.

There are many advantages to this type of crop drying method including:

• this system creates no pollution
• the solarwall is an all metal construction, ensuring a long system life
• the fan system is the only moving part, making this a low maintenance system
• low cost and easy installation
• works as a heat exchanger at night to recover waster heat from the dryers

This $1.5M project has been supported by contributions from TEAM ($582,750) and the Sustainable Built Environment group of NRCan ($175,000). It is gaining a lot of media attention. One example of the assorted media coverage received for this project was CETC Project Leader Doug McClenahan's interview by Katherine Stanley of The Tico Times (Central America's Leading English-Language Newspaper) on the benefits of solar-dried coffee.

"Coffee is dried at around 60 degrees Celsius, a fairly low temperature compared to many other crops," McClenahan said. "Solar collectors can be very efficient and low-cost at that temperature."

"With enough funds for six to eight test sites and one under way in Panama, NRCan wanted to undertake a project with a cooperative in a country with a reputation for premium coffee," McClenahan said. "Costa Rica was an obvious choice." The organization visited several coffee processing plants and chose Coopeldos, which stood out because of its strong organization and history of using "clean technologies", he added.

What does the road ahead hold for this innovative solar coffee-drying technology?

"We're going to monitor each one of these demonstrations, including the Coopeldos project for at least a full growing season," McClenahan said. "We hope to then present the results to the coffee industry."

CETC-Ottawa will continue to be a key participant in the fostering of opportunities for this innovative Canadian technology by building and expanding relationships with industry and international organizations.