Improvement of Efficiency and Environmental Impact of a Low-Cost Food Dehydrator

Energy use and carbon emissions are important factors in food industry and in food dehydration in particular. A low-cost, small-scale dehydrator was tested to determine the impact of ventilation waste heat recovery (VHR) on its en- ergy efficiency and carbon footprint. Cilantro, an important cash crop, was dried under three ventilation conditions while product moisture loss and energy use in the dehydrator were recorded. The ventilation conditions were: without VHR, with VHR, and with VHR and exhaust recirculation. Coefficient of performance (COP) for dehydrator operation under each operating condition was 0.135, 0.187, and 0.194 respectively. Tonnes of carbon dioxide equivalent produced when operating the dehydrator were 20.0, 13.1, and 18.0 for the same conditions. COP of the dehydrator increased 39% when a VHR system was added and carbon emissions equivalent was reduced by 35%. Product drying time was also reduced when the VHR system was added to the dehydrator, increasing the amount of production time available.