Sustainable thermoelectric energy harvesting in fly ash bamboo fiber reinforced concrete for smart infrastructure

Abstract

Concrete is widely used in infrastructure, and its waste heat recovery for thermoelectric power generation holds remarkable potential for energy utilization. However, optimizing the thermal conductivity of concrete to enhance thermoelectric conversion efficiency remains a critical challenge. This study investigates C40 concrete modified with bamboo fibers and fly ash, evaluating the thermal conductivity and heat transfer characteristics of different concrete types. On the basis of the findings, thermoelectric generator (TEG) modules were embedded at the concrete interface, and three composite concrete structures were developed: fly ash-plain reinforced concrete, fly ash-bamboo fiber reinforced concrete, and plain-bamboo fiber reinforced concrete. The mechanical properties and electrical output of these structures were tested, and finite element simulations were conducted to assess the effects of ground temperature, relative humidity, and wind speed on thermoelectric generation efficiency. Experimental results showed that fly ash-plain reinforced concrete exhibited the highest compressive strength, while bamboo fiber reinforced concrete demonstrated superior tensile strength, highlighting the toughening effect of bamboo fibers and the micro-filling effect of fly ash. Bamboo fiber reinforced concrete had the lowest thermal conductivity coefficient, reducing it by 68.8 % compared with plain concrete, thus exhibiting excellent thermal insulation performance. The “plain-bamboo fiber concrete” structure was found to maximize the temperature gradient, thereby enhancing thermoelectric conversion efficiency. Simulation analysis further revealed that ground temperature is the dominant factor affecting thermoelectric performance. This study elucidates the relationship between the thermal properties of concrete and thermoelectric generation efficiency, providing theoretical support for renewable energy utilization and the design of smart, sustainable infrastructure. Future work will focus on scaling up the system for real-world applications and integrating phase-change materials to improve thermal regulation further.