One of the most significant engineering and societal challenges of today is the continued availability of clean energy with minimal environmental penalties. The current energy landscape is dominated by fossil fuel combustion, which releases waste heat and carbon dioxide into the atmosphere. This leads to significant environmental consequences that are worsening each year.
Heat-driven energy systems have the potential to address these concerns effectively and offer additional advantages, such as durability, flexibility and energy-efficiency. Funded by the U.S. Department of Energy and National Science Foundation, my Adsorption and Energy Technology Laboratory at Florida Tech focuses on designing and demonstrating a portfolio of these heat-driven energy conversion and storage systems.
The central theme in my research is an energy transport phenomenon called “adsorption.” It’s a process of preferential attraction in which low-density gaseous molecules, such as those making up carbon dioxide (CO2), cling to a high-density solid surface. This phenomenon can be controlled by either the temperature of the solid or the pressure of the gas. The existing embodiments of these adsorption systems, however, suffer in performance and scalability. They use easy-to-fabricate packed adsorbent beds (like silica gel sachets in medicine jars), that limit heat and mass transport.
“The central theme in my research is an energy transport phenomenon called ‘adsorption.’ It’s a process of preferential attraction in which low-density gaseous molecules, such as those making up carbon dioxide (CO2), cling at a high density onto a solid surface.”
– darshan pahinkar, Assistant professor, mechanical engineering
These two issues can be solved using adsorbent-coated channels, which provide excellent heat and mass transfer characteristics. Such designs eliminate the flow resistance because dedicated flow passages and thin adsorbent layers result in rapid heat and mass exchange, unlike in clunkier adsorbent blocks.
I have demonstrated that this geometry can improve the adsorption-based CO2 separation system capacity by up to two orders of magnitude while maintaining the purity, recovery factors and energy requirement of existing systems. Analogous design can also make very compact heat-driven refrigeration, cooling and heat storage systems.
Thin and porous adsorbent coatings are required to materialize these designs. Our lab has created a portfolio of adsorbent coating techniques that are well-calibrated for void volumes, gas uptake (water and CO2), strength and durability. These techniques, including dipcoating, capillary insertion, photopolymer resin curing and yeast engineering, are diverse in terms of approach.
We are also studying the rheology of these complex adsorbent slurries for further refining these manufacturing techniques. These techniques have yielded excellent results in creating spongy and robust adsorbent coatings on the walls of channels. We are also involved in engineering the surface of these coatings to make them hydrophobic for seamless interactions with liquid water.
Our lab has incorporated these techniques to explore removal of carbon dioxide from post-combustion and industrial gaseous waste in an energy-efficient and spatially competitive manner. We have also demonstrated a cooling system that uses resin-cured adsorbent coatings. This system uses heat to circulate refrigerant water in one minute and provide cooling for more than five minutes without using any electricity. This cooling system can be highly competitive in the mainstream HVAC landscape.
With an interdisciplinary approach involving materials, chemical and mechanical engineering, we hope to generate decentralized solutions to mitigate environmental concerns.
Darshan G. Pahinkar is an assistant professor in the mechanical and civil engineering department. He is the director of the Adsorption and Energy Technology Laboratory, and his research is focused on devising heat-driven energy systems.
This piece was featured in the spring 2025 edition of Florida Tech Magazine.
