Solar box recovery of mixed-wax candle fragments and reuse on the island of Crete

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

doi:10.59400/esc4099

Solar box recovery of mixed-wax candle fragments and reuse on the island of Crete

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 P. Dowling
School of Mechanical and Materials Engineering, University College Dublin, D04 V1W8 Dublin, Ireland

Article ID: 4099

DOI: https://doi.org/10.59400/esc4099

Keywords: solar box cooker, candle wax, wax recovery, wax re-casting, thermodynamics

Abstract

This paper investigates the proof of principle of small-scale off-grid solar thermal batch recovery of candle wax on the island of Crete in astronomical winter season, where the Sun’s irradiance is in the range of 820–940 W×m⁻². The investigation was carried out based on the recovery of unconsumed mixed petroleum-based paraffin and plant-based soy and palm-wax (250 g each) candle fragments and their re-casting into new 50–60 g blended-wax candles. Based on a converted family size (27 L) solar box cooker the investigation is conducted during the spring equinox of March 2025 and the winter solstice in December 2025. The solar box cooker conversion extends its functionality from simple food cooking and culinary leaf dehydration to the circular economy of mixed-wax fragments recovery and reuse thereby increasing the cost-benefits of the cooker. Sensible heat measurements and latent heat of fusion calculations for the solar wax recovery process are explored; in terms of solar box cooker energy conversion to applied power (W, or J.s⁻¹) into the wax phase-change process, wax energy budget (J), and wax energy density (J.g⁻¹). The challenge in sourcing pre-used temporary and permanent molds is explored along with solar heated water used for releasing of the blended wax From a circular economy perspective, the off-grid solar box cooker design allows future scaling-out to a possible 1 kg of mixed-wax recovery, when solar processing is performed at, or around, the time of the summer solstice where solar irradiance is strongest (typically, 1,020 W×m⁻²) and increased available daylight hours allow a third, and possibly a fourth 250 g of mixed-wax to be recovered and re-cast.

Published

2026-03-18

How to Cite

Law, V. J., Lalor, J. F., Magnes, J., & Dowling, D. P. (2026). Solar box recovery of mixed-wax candle fragments and reuse on the island of Crete. Energy Storage and Conversion, 4(1). https://doi.org/10.59400/esc4099

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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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