Abstract
The chill-on-demand system is a technology designed to provide cooled products on demand, thereby avoiding any requirement for chilled storage. It uses the cooling effect provided by the endothermic desorption of carbon dioxide previously adsorbed onto a bed of activated carbon contained in an inner component of the self-chilling product. This has the potential to be applied to any type of product that needs to be cold at the point of consumption. The principles of life cycle engineering have been utilized to evaluate the overall environmental performance of one possible application of this technology: a self-chilling beverage can, with a steel outer can to contain the beverage and an inner aluminium can to contain the adsorbent. The primary aim of this research is to devise a way to ensure that the self-chilling can supplies the best cooling performance with minimal global environmental impact. First, the adsorption/desorption process as a means of cooling was investigated, together with its application to the specific case of carbon dioxide adsorbed on a bed of activated carbon obtained from coconut shells. A specific experimental activity was designed and supported by the implementation of a transient heat exchange model. Next, the potential environmental impacts of the product were evaluated by using a Life Cycle Assessment tool. The analysis considered all the life cycle stages of a self-chilling can: from the manufacture of each part of the beverage container, to its utilization and end-of-life management. The results, compared with those of a conventional beverage can, highlight the importance of using activated carbon derived from biomass and locating its production in countries with a low carbon-intensity electricity supply. More substantial environmental and technical improvements would depend on finding adsorbents with much larger capacity, and developing a system with very high rates of recovery and re-use.