Towards Whole Day Thermoelectric Energy Scavenging from Solar Using Carbon Based Photothermal Nanofluid

Abstract

Direct energy harvesting using thermoelectric energy conversion of large amounts of low-grade thermal energy into electricity is a promising sustainable green technology. Solar thermal energy systems, specifically solar hot water household heating or storage systems, are commonly considered to be the most cost-effective alternatives to fossil fuel hot water heating systems. However, many hybrid systems found in the literature are still unable to generate electricity efficiently at night, when family users consume the most. This research demonstrates electrical energy scavenging from solar heat by using a thermoelectric generator that is driven by water-based carbon nanofluid as heat storage. Furthermore, a sensible heat storage medium is tested using nanofluids such as water, graphite, graphene oxide and carbon nanotubes. This study shows successful proof of concept of carbon nanotube as the best light-absorbing carbon material that has been tested and is capable of powering up a 2 Mohm light device during the night and sustaining it for a minimum of 4 h using 1 L volume of nanofluid without emitting any greenhouse gases.