Updated on January 5, 2024


Created on August 27, 2015

Zero Emission Fridge for Rural Africa (ZEFRA)

Upcoming Update

The Zero Emission Fridge for Rural Africa is a cooling silo built using bamboo and clay, with a vermin control system for storing grains.

Tested By
  • HELVETAS Swiss Intercooperation
Content Partners


Product Description

Zero Emission Fridge for Rural Africa (ZEFRA) also known as Silo Tehetere is a seed storage silo built with local materials. It supports subsistence farmers in Mozambique to sustain food security through reduction of post-harvest losses. Furthermore, the silo helps the farmer families to adapt to climate change that is extending the drought-caused October-to-January ‘hunger period’.

Target SDGs

SDG 2: Zero Hunger

Market Suggested Retail Price


Target Users (Target Impact Group)

Household, Community, Small and Medium-sized Enterprises

Distributors / Implementing Organizations

HELVETAS Swiss Intercooperation

Manufacturing/Building Method

Individually built by farmers with support/ instruction from HELVETAS Interview with representative

Intellectural Property Type

Trade Secret

User Provision Model

The ZEFRA construction relies on existing local knowledge/expertise. Users are responsible for procurement of necessary construction materials. Helvetas Mozambique is available to provide support.

Distributions to Date Status

More than 800 were built and used in 2010 in Mozambique, each of them benefiting an average of 10 families.

Materials of construction

Weaved bamboo structure covered with clay on both sides

Grain storage duration

4 months

Holding Temperature (°C)


Protection from insect entry


Storage capacity (kg)


Temperature control


Design Specifications

The basic design of the ZEFRA is a weaved bamboo structure covered with clay on both sides. The clay case of the silo seals the seeds in an almost hermetic chamber and improves the effect of the organic, herbal repellents, which is used to inhibit insects such as the granary weevil. It stands on a base that incorporates vermin traps to protect the grain from rats and mice. The ZEFRA is installed under a simple shelter to maintain cool, dry and constant conditions.

Product Schematics

Technical Support

Together with the local NGO AMA (associação do meio ambiente) Helvetas Mozambique provides training courses for post-harvest techniques including the construction of silos Tethere, climate mitigation, post-harvest, seed-bank management, leadership and conflict management. Interview with representative

Replacement Components

ZEFRA construction materials include bamboo and clay and can be replaced based on local availability.



Manufacturer Specified Performance Parameters

The product is designed to reduce post-harvest losses and establish seed banks that store sufficient seed reserves.

Vetted Performance Status



There are no known safety risks linked to the use of this product

Complementary Technical Systems


Academic Research and References

George, M. L., 2011, Effective grain storage for better livelihoods of African farmers project: Completion report June 2008 to February 2011.

Tefera, T., Kanampiu, F., De Groote, H., Hellin, J., Mugo, S., Kimenju, S., Beyene, Y., Boddupalli, P. M., Shiferaw B. and Banziger, M., 2011, The metal silo: An effective grain storage technology for reducing post-harvest insect and pathogen losses in maize while improving smallholder farmers’ food security in developing countries. Crop protection, 30(3), pp 240-245.

Compliance with regulations


Other Information

This video shows the construction of ZEFRA HELVETAS Swiss Intercooperation The basic design of the ZEFRA This Animated Video showing the schematics of ZEFRA  

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