In addition to being environmentally friendly is a versatile modular concept application.

At the request of an agro-food company, researchers at CIATEQ (Advanced Technology Center) in Mexico, designed a flat solar collector for the drying of food products such as fruits and vegetables, which can achieve air temperatures up to 77 °C.

While the solar collector required to the Research Center had to replace gas consumption to power a steam generator, the final development not only uses friendly energy for the environment, it can also result in lower costs in making and operation once the manufacturing process is optimized.

Dr. Agustin Escamilla Martinez, leader of the project, told us that the idea arised between CIATEQ and the company Maquinaria Jersa, with the support of the National Council of Science and Technology (Conacyt).

The solar collector developed is of the watertight air type, which is divided into two parts: the first is exposed to the sun and is protected by a glass on top of a kind of container where housed air does not move; in the second part, the bottom is protected by corrugated aluminum painted matte black.

"This air that doesn’t move is heated through the glass by the sun, and the heat generated is transferred through the corrugated sheet if aluminum at the bottom; it has an inlet through which ambient air circulates in a motion similar to a coil, thus longer residence time is achieved, later exciting trough the sides.

"The solar collector heats air while it passes through its interior, and applying techniques of computational fluid dynamics drawbacks in the design were discarded, optimizing the energy balance for the equipment," explains Dr. Escamilla.

He adds that among the tests carried out for the company a series connection of collectors were made, since air increased its temperature when passing a collector, three in series were placed, and what was obtained was air discharged into the drying tunnel 20 degrees hotter than the circulating in the environment, in a flow of 26 cubic meters of air per minute.

In field tests, the arrangement in series reached a power of 7.1 kilowatts, an increase in temperature of 44 degrees Celsius, and an efficiency of 40 percent. The CIATEQ researcher explains that with the above results both the design and simulation were validated.

"Importantly, we reach maximum temperatures of 77 degrees, because if we applied more heat to the product it would degrade and lose quality," explains Dr. Escamilla.

Finally, he points out that the development was installed in the pilot plant of the company that hired the development, where four sets of three solar collectors were placed.

"This concept can be applied to any situation where the heating of air not exceeding 80 degrees Celsius is required, based on an energy diagnosis of the application site," he concluded. (Agencia ID)