Title : Solar box recovery of mixed-wax candle fragments and their reuse on the island of Crete
Abstract:
This paper investigates proof-of-principle of small-scale free solar energy batch (2 x 250 g) recovery of unconsumed mixed (petroleum-based paraffin and bioparaffins)-wax candle fragments and its re-casting into new 50-60 g blended-wax pillar candles. Based on a converted family size (27 litres) solar box cooker the investigation is performed during the spring equinox of March 2025 and the winter solstice month of December 2025 on island of Crete. During this period the Sun’s irradiance is in the range of 820 to 940 W-cm-2. The solar box cooker conversion extends its function from a simple food cooking and culinary leaf dehydration into the circular economy of mixed-wax fragments recovery and reuse. This approach therefore increases the cost-benefits of the cooker. Sensible heat measurements and leant heat of fusion calculations for the solar wax recovery process is explored; in terms of solar box cooker energy conversion into applied power (J.s-1) into the wax phase-change process, wax energy budget (J), and wax energy density (J.g-1). From a circular economy view-point, the challenge in sourcing second-hand temporary and permanent molds, and the release of the blended wax from its temporary mold using solar box cooker heated water is exemplified. The solar box cooker design allows future scaling-out, rather than scaling-up, 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, 1020 W-cm-2) and increased available daylight hours allow a third, and possibly a fourth 250 g of mixed-wax to be recovered and re-cast.
