Commercial Solar Dryers

Grekkon Limited is the largest supplier of commercial solar dryers for agricultural products in east Africa.  These are drying units that work on solar strength. Our commercial low cost solar dryers design is according to the product, location, and drying volume per session. This passive or active solar dryers for fruits and vegetables is fixed or portable as the user needs it

Solar dried mango slices

Types of Solar Dehydrators in Kenya

Grekkon limited designs and constructs both passive/ natural circulation, and active/ forced circulation solar dryers. The passive solar dryers have no additional mechanical input, while the active dryers do. Additional mechanical inputs are;  a biomass heating unit, or solar powered exhaust and extraction fans, and synchronizers. These enhance drying time by 30% to 100% compared to passive drying. Attached biomass heating units allow for night time drying, or on cloudy/ rainy days.

Components of our Solar Dryers

• Light UV treated translucent polythene paper to allow heat and light. The paper also has anti-drip treatment to prevent dew formation which causes moulds to form on food
• Heavy UV treated geomembrane to conserve heat
• Steel bars galvanized with food-grade aluminum or zinc for food safety
• UV treated heavy gauge netting to prevent insect pests from entering

Below are 2 videos: The first one is of a farmer in Homa-bay county, western Kenya using a community passive/ natural circulation solar dryer to add value to banana produce. The second one is of a mango processor in Taita Taveta county at the county’s coast with an active/ forced circulation dryer. Both solar dryers are by Grekkon Limited.

Video 1.

Video 2.

Our solar dryers for fruits and vegetables have shelves at different levels depending on the volume or weight of food crops to dry per session.

Solar Dryer Working Principle

What is the working principle of a solar dryer?

1. Passive/ Natural Circulation Commercial Solar Dryer

Grekkon Limited solar dryers work in the following steps;

i. Capture & collect the sun’s heat

ii. Create a ‘greenhouse effect’ which causes moisture loss from the produce

iii. Air coming into the dryer exits with this moisture from the vent

2 Active/ Forced Circulation Commercial Solar Dryer

In addition to what takes place in the passive solar drying unit, the fans force in hot air from outside, and force out hotter air combined with moisture from inside the dryer. At night or on cloudy/ rainy days, the biomass unit supplies the drying heat.

Pros and cons of a solar dryer

1. Speed of drying. Food dries four to five times faster.
2. Quality. As the sun’s UV rays do not get into direct contact with the drying food, its, color, taste, scent, and nutritional value is unaffected
3. Cleanliness. The food is free from dust, sand, or other external contaminants
4. No pests. Insect, bird, or mammalian pests have no access to food in the dryer, so no attack occurs
5. It is more expensive to build and maintain than open-air drying

Solar dried chilli peppers

Commercial solar dryers FAQs

III. What does a solar dryer do?

Grekkon Limited’s solar dryers reduce the moisture content to less than 12% in these products;

• Plantation crops; coffee, rice, cassava
• Vegetables; tomato, onion, garlic, brassicas, hot peppers
• Cereals; sorghum, and millet
• Herbs; moringa, mint, rosemary
• Oil crops; groundnuts, sunflower, macadamia, cashew nuts
• Others; mushrooms, fish, beef, mutton

IV. How do you dry vegetables with solar?

• Wash the vegetables to remove all dirt
• Ensure there are no insect pests present
• Remove any diseased parts or produce
• Cut or grind them into smaller pieces to increase the drying surface area

Place them in the solar dryer holding trays

Dry cassava chips

V. What is the most popular use of solar dryers?

To dry fruits ,  mushrooms, vegetables, herbs, spices, coffee, cassava, banana and fish. Banana and cassava are further processed into food flour

VI. What are the main applications of a solar dryer?

Besides vegetables and fruits, commercial solar dryers in Kenya  are for fish,  root crops and mushroom drying. Commonly dried foods in Kenya through our solar dryers are:

i. Banana, cassava, pumpkin, millet, and sorgum to make food flour. Dried cassava is also processed for industrial starch manufacture

ii. Moringa as a medicinal herb

iii. Tomato, capsicum, traditional vegetbles, kales, and spinach  as vegetable nutrients

iv.  Mango, papaya, as dried fruits for snacking

v.  Omena which is the silver cyprinid fish for both human consumption, and as additive to animal feed

vi. Coffee so that it’s suitable for milling. Coffee solar dryers are the largest, each holding over 5 tons of berries per  drying session