Solar Dryers (PA Technology)

Last modified by Franz Schreier on 2015-01-27. This is a wiki so please feel free to update information by clicking on "Edit with form". | Printable version

Name of technology example:		Type
Solar Dryers		☐ Energy Efficiency ☑ Renewable Energy ☐ Alternative Methodology

Description

Solar dryers are devices that use solar energy to dry substances, especially food. There are two general types of solar dryers: Direct and indirect.

Direct solar dryers expose the substance to be dehydrated to direct sunlight. They have a black absorbing surface which collects the light and converts it to heat; the substance to be dried is placed directly on this surface. These driers may have enclosures, glass covers and/or vents to in order to increase efficiency.

In indirect solar dryers, the black surface heats incoming air, rather than directly heating the substance to be dried. This heated air is then passed over the substance and exits through a chimney, taking moisture from the substance with it. Dependency from sun radiation can be reduced by combination with other available heat sources.

(Source: http://en.wikipedia.org/wiki/Solar_dryer)

Technology for the Application of

☑ Solar	☐ Biomass	☐ Biofuel
☐ Biogas	☐ Wind	☐ Geo-Thermal
☐ Hydro	☐ Energy Efficiency
☐ Other: /

Primarily Relevant for the following Agricultural Value Chain Steps

☐ Mechanization	☐ Efficiency of Operation	☑ Processing
☐ Transportation	☐ Controlled Atmosphere	☐ Controlled Temperature
☐ Mechanical Sorting	☑ Preservation
☐ Other: /

Primarily Relevant for the following Agricultural Value Chain Activities

☐ Grinding	☐ Hauling and conveying	☐ Sorting
☐ Seedbed Preparation	☐ Milling	☐ Tearing
☐ Planting	☐ Washing	☐ Mixing
☐ Pumping	☐ Heating	☑ Drying
☐ Irrigation	☐ Cooling	☐ Animal feeding
☐ Fertilizing	☐ Venting	☐ Animal health and Welfare
☐ Pest Management	☐ Lighting	☐ Packing and branding
☐ Cutting	☐ Sanitation
☐ Other: /

Primarily Implemented in the following Commodity Groups

☑ Cereals	☑ Fruits and vegetables	☐ Nuts and berries
☐ Forage	☐ Dairy products	☐ Meat products
☐ Oil Seeds	☑ Roots and Tubers	☐ Eggs
☑ Pulses	☑ Fiber Crops	☐ Forestry
☐ Sugars	☐ Stimulants	☑ Spices
☐ Other: /

Region & Country of
Development

N/A

☐ Africa
☐ South Asia
☐ East Asia & The Pacific
☐ Europe & Central Asia
☐ Latin America & The Caribbean
☐ Middle East & North Africa
☐ North America
☐ N/A: /

Region & Country of
Current Deployment

N/A

☐ Africa
☐ South Asia
☐ East Asia & The Pacific
☐ Europe & Central Asia
☐ Latin America & The Caribbean
☐ Middle East & North Africa
☐ North America
☐ N/A: /

Region & Country of
Potential Deployment

Worldwide

☑ Africa
☑ South Asia
☑ East Asia & The Pacific
☑ Europe & Central Asia
☑ Latin America & The Caribbean
☑ Middle East & North Africa
☑ North America
☐ N/A: /

Manufacturers

Many manufacturers in many countries; high quality technologies see for example www.cona.at or www.grammer-solar.com; Many low cost solutions are locally available.

Economics

Increases independency from fuels; In many cases an economic way to dry food;

Technology Development Level

Low to high depending on size, purpose and source. So far, ETFE film as cover material has not yet been used. Implementing ETFE film to some of the existing systems might be an easy way to increase the efficiency of the device and to reduce material cost and provide longer life time - especially for the simple versions.

Required Maintenance Technical Level

Low to medium, depending on the system;

Required Infrastructure for Deployment

Plain ground;

Required Resources during manufacture

Glass, transparent plastics, metal, timber;

Required Resources during operation

In some cases electricity for the operation of ventilators;

Deployment
Level

Deployment Capability and Potential

High;

Requirements for Deployment

Developing a standard well performing solar dryer with longlasting materials (like ETFE), efficient ventilation supplied with photovoltaics, spread knowledge;

Relevance for Autonomy and Food Security

High - reduces dependency on fuels, improves the present situation (avoids transport losses, avoids contamination of food when in-approriate spots are used to dry food, provides the option to produce high quality dry products and to open new markets for the users);

Environment Impacts (emissions)

None;

Conformity with Bio- Cybernetic System Rules

100%

Additional information / Comments

No comments.

Internal Reference

Additional Links

http://en.wikipedia.org/wiki/Solar_dryer

http://intranet.eng.unsw.edu.au/node/608

http://www.builditsolar.com/Projects/Cooking/cooking.htm#Drying

https://practicalaction.org/a-simple-solar-dryer