From biomass residue to solar thermal energy: the potential of bagasse as a heat storage material

Abstract

Solar energy is an ecofriendly potential alternative to nonrenewable sources of energy, which are becoming increasingly scarce. Issues with the use of solar energy, such as temporal variations in the intensity of sunlight, could be solved by storing solar energy. This work introduces the concept of using waste as a sustainable material for energy storage. Sugarcane crop is a potential feedstock for the agro-industry in Egypt. However, while sugarcane is a source of both ethanol and sugar, extracting these substances from sugarcane results in a significant amount of solid biomass waste, known as “bagasse”. This investigation demonstrates that sugarcane bagasse, which is produced in increasingly large quantities each year, could be employed in a cost-efficient method of storing solar energy. In this study, the bagasse was modified using facile chemical and thermal treatments and then examined using XRD (X-ray diffractometry) and SEM (scanning electron microscopy), which revealed the presence of quartz. An inexpensive solar energy storage material was then created by impregnating paraffin wax with the treated bagasse using an ultrasonic technique. This composite material showed excellent form-stable phase-change behaviour that allowed it to absorb large amounts of solar energy, especially around solar noon, and store that energy in the form of heat. The composite was found to store 72 kJ/min of heat, as compared to only 7 kJ/min for pure paraffin. Thus, this study suggests that a composite material capable of enhanced solar energy storage can be created from industrial waste, permitting an environmentally integrated approach to storing green energy.