Solar Tunnel Drying App
User guide for operating the solar tunnel drying App

1. Introduction 

Solar drying is one of the most effective ways of reducing post-harvesting losses in Africa. Realizing the immense potential presented by the dryers, agricultural practitioners are doing their part to ensure the technology serves its purposes. Agricultural engineers around the world are coming up with improved designs of the structures. Other climate change actors like Dr. Munang are showcasing the technology through initiatives such as Innovative volunteerism. In keeping with these excellent examples from field actors, the developers, and engineers at decided to develop this App to ensure solar drying serves its purpose of reducing post-harvesting losses in Africa.

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2. Justification for the App

From our experience, we gathered that the collector area, tray area, and the number of chimneys to use are the main factors that affect the performance of Tunnel dryers in Africa. These elements have to be designed following thermodynamics equations, which are beyond the scope of some users of the dryers. To circumvent this problem, we inserted the equations in an excel sheet that was used to develop this Application. The Application allows users to enter the volume of products they intend to dry, moisture contents, ambient temperature, and the wind speed in their area. The App will then make the necessary calculations and output the collector area, tray area, and the number of chimneys to use in your tunnel dryer.

 Acces the App here 

3. Using the App

To use the App, one needs to insert the necessary variables, namely the mass of product to dry, the initial moisture content at harvest, final moisture content, wind velocity, and ambient temperature. The App will then generate the Collector Area, Number of chimneys, and Surface Area of the drying bed to adopt when constructing your tunnel dryer in the first row of output. The subsequent rows show the technical calculations that led to the output.

Access the App here 

4. Scope

The App was designed to work with tunnel dryers and may not be effective in other types of dryers. It was also designed to work with Cassava products. However, it can work just as fine with other products, given the equations of design are largely the same. Nevertheless, we encourage users to share their designs for review by our engineers before adoption for best results.


5. Terms

Initial mass of material to dry: this variable denotes the mass of the product that one intends to dry in the tunnel dryer

Initial and final moisture content: This denotes the crop's moisture content at harvest and the targeted moisture content for storage. A quick internet search of the moisture contents of various crops can yield this information reasonably quickly

Wind velocity: This is the speed of wind in m/s in the project area. Again, a quick internet search of the wind speed in a given area will readily give this information.

Ambient Temperature: This is the room temperature in the project area. Like the other variables, a quick internet search should reveal this information.

Collector area: This is the area of the solar absorbent material to use in the tunnel dryer. Since the figure is close to the floor area, one can use it to come up with the appropriate dimensions of the floor of the tunnel dryer.

Number of chimneys: This refers to the number of chimneys to insert on top of the tunnel dryer.

Surface Area of drying bed: This refers to the total surface area of the drying beds to use in the tunnel dryer.


Solar Drying - Part 1
Introduction to Solar Drying
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