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Quad Series

  Expandable Commercial Dryers

This economical line of commercial dryers is conveniently expandable by simply adding modules of the Quad solar air collectors and the respective drying rack capacity. This series also allows the choice of rooftop installation of the solar air collectors to feed hot air directly down into a suitable small building where the drying racks are installed in any capacity. Alternatively these collectors can be mounted on the ground directly beside the wall of the small building housing the drying racks.


Each group of four solar air collectors is matched to 2 fans, ductwork and a cabinet of 24 drying racks, so that approximately 50 - 60 KG of wet fruit can be dried at one time. By simply adding modules this can be multiplied depending on the capacity required.

The intent is to allow projects to build their own cabinets inside their building or in a dedicated shed, while the critical components are supplied, including: Solar air collectors and stands, fans, ductwork, controls, and optionally the aluminum racks.


A typical cabinet is shown here with a 24 rack capacity, matched to the single Quad solar air collector. For single installations, the cabinet can be placed directly under the air collectors. For larger projects it is recommended that a small building house the drying racks and cabinets.  Example: For a project with a 3 x Quad series capacity, a building of about 10 sq. meters is enough to house the drying cabinets with a capacity of 72 racks and  about 150 – 200 kg “wet” food drying capacity. A sturdy building with a flat roof, would allow the three quad group to be roof-mounted to take advantage of the downwards hot airflow coming out of the manifold at the bottom of the solar air collectors.



This SolarFlex Quad system, like the “Small Farm” model,  employs the high-performance horizontal airflow method through the cabinets and drying racks. This method, though slightly more complex, has been scientifically  proven to be superior to typical vertical airflow systems. Horizontal airflow allows the drying air to sweep across the surface of the food (including the “boundary layer”) which is much more efficient than pushing up air against the bottom of the food.




To maximize airflow efficiency, the Quad series draws air downwards through the collectors to allow the hot air outlet ducts to be directed into the cabinets and the building either from the rooftop installation or from the ground. The photo shows the manifold, ducts, and fans coming off the Quad collectors, and the control panel.



At left is a typical installation of three Quad collectors on the ground and below they are shown on the roof of the same building.



This sketch shows approximate size of the small building and interior space required for three Quad series collectors and their respective cabinets in the building.



Projects requiring specific configurations of 3 or more Quad dryer combinations will be provided with drawings and material specifications to allow them to prepare their own building, including drying cabinets. Turnkey packages including solar air collectors, fans, controls stands and ductwork can be supplied. Approximate price is $4,500. per complete Quad unit including cabinet and racks.