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Main indicators evaluating the performance of Solar Dryers

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Author Affiliations

  • 1Laboratoire d’Énergétique et de Mécanique Appliquée (LEMA), École Polytechnique d’Abomey-Calavi (EPAC), Benin
  • 2Takaz-Eng, 01 BP 2197, Cotonou, Bénin
  • 3Laboratoire d’Énergétique et de Mécanique Appliquée (LEMA), École Polytechnique d’Abomey-Calavi (EPAC), Benin
  • 4Biomechanics and Bioengineering, University of Technology of Compiegne, Compiegne, France and Laboratory of Innovative Technologies, University of Picardie Jules Verne, Compiegne, France and Diasporeines Africa Association, Paris, France

Res. J. Engineering Sci., Volume 15, Issue (2), Pages 21-35, May,26 (2026)

Abstract

This article presents a concise review of thirty (30) key performance indicators used to evaluate and optimize the efficiency of solar dryers during the design phase. Solar dryers play a crucial role in food preservation, food safety, and the promotion of sustainable practices. By examining these indicators, the study provides a solid basis for the design, optimization, and assessment of sustainable solar drying systems. The identified indicators are classified according to their relevance in energy, exergy, environmental, and economic analyses. From an energy perspective, drying energy efficiency (η_d) is the most commonly used parameter. At the environmental level, CO₂ emissions dominate performance assessment, while the discounted payback period (PBP) is the most widely applied economic indicator. However, the study emphasizes that relying on a combination of indicators leads to more robust decision-making. For example, in agro-food processing units, both the discounted payback period and net present value are critical economic metrics. Furthermore, the review highlights the exergo-economic indicator (Rex) as essential for optimal solar dryer design. This parameter integrates technical and economic considerations and identifies potential performance improvements at the component level. Consequently, minimizing Rexshould be a primary objective in solar dryer design.

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