Solar box cooker dehydration of culinary leaves: Leaf morphometrics and relative humidity endpoint detection

Victor J.  Law; James F.  Lalor; Jenny  Magnes; Denis Pius Dowling

doi:10.59400/esc4098

Solar box cooker dehydration of culinary leaves: Leaf morphometrics and relative humidity endpoint detection

Victor J. Law
School of Mechanical and Materials Engineering, University College Dublin, D04 V1W8 Dublin, Ireland
James F. Lalor
School of Mechanical Engineering, Technological University Dublin, D01 K822 Dublin, Ireland
Jenny Magnes
Physics and Astronomy Department, Vassar College, New York, NY 12604, USA
Denis Pius Dowling
School of Mechanical and Materials Engineering, University College Dublin, D04 V1W8 Dublin, Ireland

Article ID: 4098

DOI: https://doi.org/10.59400/esc4098

Keywords: direct solar dehydrator, leaf dehydration, endpoint detection

Abstract

Open solar dehydration has been used traditionally to remove moisture from culinary leaves in order to preserve their medicinal and nutritional qualities. This paper investigates the performance of a converted family-size (27 L) solar box cooker for solar dehydration of culinary leaves (Bay, Sweet, and Greek Basil and Common Sage). The investigation was carried out over the three month period from May to July 2025, on the island of Crete. The chosen leaves vary in their in vivo water content and leaf-blade morphology. The leaves are vertically triple-stacked within the dehydrator, and a green agricultural shadow-mesh cover is used to prevent direct solar irradiance damage. By performing solar dehydration during the day, leaf dehydration stress characteristics are identified. Solar dehydration parameters reported are: air temperature, relative humidity as a function of process time, leaf mass pre- and post-dehydration, and leaf water stress outcome in terms of visually observed leaf morphological changes (leaf rolling score and leaf shrinkage). For the top frame within the unloaded dehydrator, the relative humidity baseline follows a 4th-order polynomial time series 0D-model, with a extreme end behavior equilibrating to 8% relative humidity. Leaf-loaded studies reveal leaf water moisture is injected into the dehydrator, thereby linearizing the unloaded dehydration curve. Over a 3 to 7.5 h period of sunlight exposure, the top frame leave average a weight loss of 4.0 to 4.5 g per hour. For the partially sun blocked leaves on the middle and bottom frames, a supervised endpoint model is used, required adding approximately 1 hour to account for the longer drying time.

Published

2026-03-25

How to Cite

Law, V. J., Lalor, J. F., Magnes, J., & Dowling, D. P. (2026). Solar box cooker dehydration of culinary leaves: Leaf morphometrics and relative humidity endpoint detection. Energy Storage and Conversion, 4(1). https://doi.org/10.59400/esc4098

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Vol. 4 No. 1 (2026)

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Article

This work is licensed under a Creative Commons Attribution 4.0 International License.

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