A new study by researchers at University of Limerick has revealed a sustainable method of efficiently converting waste heat into electricity using Irish wood products, while minimising costs and environmental impact.
The groundbreaking study, led by researchers at UL in collaboration with colleagues at the University of Valencia, has demonstrated a method of generating electricity using low-grade heat recovered from lignin-derived membranes.
Lignin, typically overlooked, is a sustainable byproduct derived from wood in paper and pulp production.
The study shows that these membranes can convert waste heat into electricity by utilising the movement of charged atoms (ions) within the material.
This is a significant advancement as previous studies had only demonstrated this technology using cellulose from natural wood, and the new UL research has successfully applied it to lignin from waste wood - contributing to a more circular and sustainable economy as a result.
Low-grade heat refers to waste heat generated at temperatures below 200 degrees Celsius. In industrial processes, 66% of the waste heat falls into this category, highlighting the potential of this breakthrough for developing sustainable heat-to-electricity applications.
The NXTGENWOOD study, which was funded by the Department of Agriculture, Food, and the Marine, has been published in the Journal of Advanced Functional Materials.
Professor Maurice N Collins, Professor of Materials Science in UL’s School of Engineering and Principal Investigator at the Bernal Institute who supervised the study, explained: “Low-grade heat comes from various sources like waste heat in industries, heat losses in insulating systems, ocean thermal gradients, biomass fermentation, and solar heat.
“Despite its potential, utilising low-grade thermal energy in energy harvesting applications has been challenging due to the lack of cost-effective technologies.
“Our research explores the use of ionic thermoelectric membranes made from lignin, an underutilised by-product in the paper and pulp industry, offering a sustainable solution.”
Lead author Muhammad Muddasar, a NXTGENWOOD PhD student based at the Bernal Institute, explained: “We have developed the first lignin-based membrane for ionic thermoelectric energy harvesting.
“Our membrane is lightweight, easy to synthesise, and biocompatible, making it suitable for various applications, including thermal energy harvesting, temperature sensing, and biomedical sensors for health monitoring.”
The UL researcher’s work on the NXTGENWOOD project comes under the umbrella of the Science Federation Ireland-funded Centre for Advanced Materials and BioEngineering Research (AMBER). The project is dedicated to developing new value-added applications from Irish wood.
Professor Collins added of the environmental potential of the research taking place at UL: “While there is still room for further development in heat-to-electricity conversion applications, the study demonstrates that abundantly available lignin can successfully contribute to low-grade thermal energy harvesting, especially in scenarios where sustainability and cost-effectiveness are crucial.”