Jun 2 2016
Scientists at CIATEQ (Advanced Technology Center) in Mexico have developed a flat solar collector that utilizes solar energy to dehydrate food products, like fruits and vegetables. Developed at the behest of an agro-food company, the system is designed to attain air temperatures as high as 77°C. This latest development could be a major benefit to the food industry.
Solar collector
Although the solar collector had to substitute gas usage to drive a steam generator, the ultimate development not only utilizes eco-friendly energy but is also projected to reduce development and operation costs as soon as the production process has been optimized. Besides being environmentally friendly, the solar collector provides a flexible and modular concept application.
Dr. Agustin Escamilla Martinez, the project head, informed that the concept originated between the company Maquinaria Jersa and CIATEQ, with support from the National Council of Science and Technology (Conacyt).
The scientists designed a watertight air type solar collector system, which has two parts. The first part is exposed to the sun rays and is shielded by a protective glass on top of a container in which the contained air remains immobile, and the second part forms the base, which is shielded 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.
Dr. Agustin Escamilla Martinez, Project Head, CIATEQ
He added that among the various tests performed for the company, a set of solar collectors were developed. Three solar collectors in series were also placed because while passing a collector, air increases its temperature. It was observed that air, which was discharged inside the drying tunnel, was 20 degrees hotter when compared to the circulating air in the environment, in a flow of 26 m3 of air per minute.
With respect to the field tests, the arrangement of the solar collectors in series achieved a 7.1 kW power, an efficiency of 40% and an increased temperature of 44oC. Dr. Escamilla elaborated that both the design and simulation were corroborated with the above results.
Importantly, we reach maximum temperatures of 77 degrees, because if we applied more heat to the product, it would degrade and lose quality.
Dr. Agustin Escamilla Martinez, Project Head, CIATEQ
The CIATEQ researcher also informed that the solar collectors have been installed at the pilot plant of the company, which commissioned the work. In fact, four sets of three solar collectors have been set up at the facility,
"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.