Solar Tunnel Dryer Type "Hohenheim"


Solar drying has been practised for conservation of foods for centuries. Utilization of the sun is more actual than ever. The solar tunnel dryer type "Hohenheim" unites simple construction, use of renewable energy and aesy handling. This dryer is particularly apt for production of high quality products in agricultural enterprises. As a cooperaitve development of the Institute for Agricultural Engineering in the Tropics and Subtropics of Hohenheim University and Innotech, solar tunnel dryers are in commercial operation in more than 100 countries all over the world.





Effective conservation of fruit, vegetable, herbs, medical plants and spices

Conservation by apropriate technology is the key to successful enterprise. Whereas in the European Community approximately five percent of agricultural goods become spoiled, the amount in the tropics and subtropics rises up to 70 percent. The lack of storage facilities and little developed infrastructure hamper small producers from market entry. Seasonal surplus due harvest can not be traded and on the regional markets the prices persist at low level. As an alternative the processing of dryed products of high quality present itself. Harvest turns into storable and tradable goods for a long term. Expenditure on transportation decreases whereas benefit from additional processing remains at the producer. Stored goods are a regular source of income and diminish the dependance on seasonal harvest. Hygienic processing is the assumption for the production of high quality products. Even familiy enterprises get the chance to set on the market.





Technical Data

The solar Tunnel dryer in it's standard version is apt for drying of nearly all agricultural produce under various climatical conditions.

Lenght: 18 m
Width: 2 m
Collector area: 16 m²
Drying area: 20 m²
Air flow rate: 400-1200 m³/h
Air temperature: 30- 80 °C
Power requirement: 20- 40 W
Drive of fans: Solarpaneel
Set up: approx. 1 Day
Delivery extense: all parts, incl. replacement cover
Thermal energy gain from solar radiation: up to 60 kWh/ Tag (approx. 15 kg firewood)


Operating units

The solar tunnel dryer is used in more than 100 countries, e.g. in:



Simple technology meets high utilization

The appropriate construction guarantees easy installation as well as transportation. Without any reconstruction the dryer is suitabe for fruits, vegetables, spices and medical plants. Even under adverse weather conditions the operation of the dryer is reliable. Seasonal overproduction as well as over- and undersizes are processed to valuable goods. The applicants of solar tunnel dryers are agricultural enterprises, familiy run farms and developing organisations which demonstrate improved technology. With good results the dryer was also operated by women groups in developing countries to contribute to familiar income. Also an increasing number of organic farmers use the ecological advantages of the solar tunnel dryer for the production of their high-value crops