A mass-heater supplemented greenhouse dryer is shown to be an adaptable technology to post-harvest preservation problems in developing countries. Inadequate harvest preservation in these countries often leads to a cycle of bumper harvest and production cutbacks, famine, inability of famers to get their harvest to the market, low quality of exports, and low agro-processing. Drying is a preservation technique that is readily adaptable for developing countries, and the earliest form of this method, open air drying, is still predominant. Rigorous designs are not always possible or economical, but the greenhouse dryer will always outperform open air drying irrespective of the quality of its design. Greenhouse dryer design parameters are identified, and guidelines for optimizing performance are provided. Mass-heaters based on rocket or top-lit-up-draft heaters, fueled by agricultural wastes, are proposed as supplementary heat sources when the sun is not available at night or during cloudy periods

Concentrated Solar Thermal (CST) is a proven renewable energy technology that harnesses solar irradiation in its most primitive form. This technology with roots in ancient history is growing at a fast pace in recent times. Developing countries could use CST to solve fundamental human-needs challenges, such as for the substitution of fuelwood and the treatment of water for household use. This paper proposes a conceptual design for a standardized modular CST for these applications in developing countries. A modular-designed parabolic CST with an aperture area of 7.5 m2 is adequate to provide enough solar thermal energy to replace the fuelwood need (5 tons/yr) or to pasteurize the minimum daily water requirement (2500 liters) for a household. Critical parameters of the CST are discussed and an affordable solid thermal storage is recommended to be used as a backup when sunlight is unavailable. A funding program that includes in-country resources and external funding will be needed to sustain the development and wide spread adaptation of this technology.