Heat-storing salogels offer a potential path to efficient buildings

Texas A&M researchers review polymer-salt gels for passive temperature regulation

By LineZotpaper

Published19 October 2026

Read Time2 min

A review from Texas A&M University highlights the potential of salogels, polymer gels loaded with hydrated salts, to passively regulate building temperatures. The materials absorb heat by day and release it at night, a cycle that could substantially reduce the energy buildings consume for heating and cooling.

Researchers at Texas A&M University have reviewed a class of materials called salogels, which could help reduce the energy buildings burn on heating and cooling.

Salogels are polymer gels loaded with hydrated salts that trap water inside their crystals. They work as phase-change materials (PCMs), absorbing thermal energy as they melt and releasing it as they solidify. Compared to wax-based PCMs like paraffin, these hydrated salts can store more than twice as much heat per volume. They are also non-flammable and can be cheap, with some being industrial byproducts.

Previous attempts to use such salts in construction were hampered by leaking and separation when melted. Salogels solve this by using a polymer network to hold the salts in place. Reversible polymer bonds allow the material to retain 80% to 95% of its heat-storage capacity.

Kartik Kumar Rajagopalan of the university's Soft Matter Facility, one of the study's authors, said the materials represent "a shift from simply storing heat to engineering multifunctional materials that combine thermal energy storage and conversion."

The research proposes two building applications. A passive route embeds the gel in roofs, walls, or windows, letting it ride the day-night temperature swing. A dynamic route loads it into modules for air-conditioning or water heaters. Small-scale tests have been promising. In a 3D-printed house, a salogel wall coating kept interiors cooler in the day and warmer at night. In windows, the gel turns transparent and cools during melting, then turns opaque and releases heat as it crystallizes.

Significant hurdles remain. The best heat-storing gels are soft, while firmer gels store less energy. Some salts can also stay liquid below their freezing point, a problem the polymer network helps with but does not fully solve. The longevity of the materials and their real-world energy savings are still unknown.

The authors propose the use of AI and simulation to develop new polymer-salt combinations, and suggest salt blends with tunable melting points. The final aim is a tough, recyclable material that can perform for years inside buildings.

Analysis

Why This Matters

Building heating and cooling accounts for a major portion of global energy use. Materials that passively manage temperature could dramatically cut demand.
Salogels promise better performance than current PCMs at a lower cost, which could accelerate adoption in general construction.

Background

Phase-change materials (PCMs) have long been explored for thermal storage. Paraffin waxes are the standard but have low heat capacity and are flammable. Salt hydrates have higher capacity but leak when liquid. Salogels represent a materials-science solution to that containment problem by using polymers to hold the salt.

Key Perspectives

[Texas A&M Researchers]: The team presents salogels as a promising new platform for building thermal regulation, combining high storage capacity with structural versatility. They propose AI-driven design to accelerate development. [Study's Own Cautions]: The authors do not claim a ready solution. They highlight specific obstacles: the inverse relationship between gel firmness and storage capacity, the risk of supercooling, the lack of understanding of how the polymer network triggers crystallization, and the unknowns in manufacturing and long-term cycling.

What to Watch

Pilot demonstrations integrating salogels into building components for real-world testing.
Computational models and AI simulations identifying optimal polymer-salt combinations that balance strength with high heat capacity.

Sources

Heat-storing gels regulate building temp to slash energy bills · New Atlas: Technology-Innovation-Outdoor News

Checked

12 claims in this story checked against 1 source: 10 supported.

Show each claim

SupportedSalogels could help reduce the energy buildings consume for heating and cooling.New Atlas: Technology-Innovation-Outdoor News: “An emerging class of heat-storing gels is out to reduce the energy our buildings burn on heating and cooling.”
SupportedTexas A&M researchers reviewed polymer-salt gels (salogels) for passive temperature regulation.New Atlas: Technology-Innovation-Outdoor News: “In a recent study, researchers at Texas A&M University review how these gels have evolved and how they might be used in construction.”
SupportedKartik Kumar Rajagopalan of the Soft Matter Facility, one of the study's authors, said the materials represent "a shift from simply storing heat to engineering multifunctional materials that combine thermal energy storage and conversion."New Atlas: Technology-Innovation-Outdoor News: “"Salogels represent a shift from simply storing heat to engineering multifunctional materials that combine thermal energy storage and conversion," said Kartik Kumar Rajagopalan of the university's Soft Matter Facility, one of the study's authors.”
SupportedHydrated salts can store more than twice as much heat per volume as paraffin.New Atlas: Technology-Innovation-Outdoor News: “the salts, which can store more than twice as much heat per volume as paraffin”
Partly supportedReversible polymer bonds allow the material to retain 80% to 95% of its heat-storage capacity.New Atlas: Technology-Innovation-Outdoor News: “Versions that use reversible bonds, which can break and re-form, keep 80% to 95% of the pure salt's heat-storage capacity.”
SupportedSalogels are polymer gels loaded with hydrated salts that trap water in their crystals and work as phase-change materials.New Atlas: Technology-Innovation-Outdoor News: “The materials are called salogels, polymer gels loaded with hydrated salts that carry water trapped inside their crystals.”
SupportedPrevious attempts to use such salts in construction were hampered by leaking and separation when melted.New Atlas: Technology-Innovation-Outdoor News: “When they melt, they turn to liquid, leak away and sometimes separate into layers.”
SupportedThe review proposes a passive route for roofs, walls or windows and a dynamic route for air-conditioning units or water heaters.New Atlas: Technology-Innovation-Outdoor News: “A passive route tucks the material into roofs, walls or windows, where it rides the swing between day and night temperatures. A dynamic route loads it into modules such as air-conditioning units or water heaters.”
SupportedIn a 3D-printed house, a salogel wall coating kept interiors cooler in the day and warmer at night.New Atlas: Technology-Innovation-Outdoor News: “a salogel coating on the walls of a 3D-printed house kept the interior notably cooler during the melting phase, and much warmer during crystallization, compared to an identical house without it.”
SupportedIn windows, the gel turns transparent and cools during melting, then turns opaque and releases heat as it crystallizes.New Atlas: Technology-Innovation-Outdoor News: “In windows, the gel melts by day, turns transparent and cools. At night it crystallizes, gives off heat and turns opaque.”
Partly supportedHurdles remain: firmer gels store less energy, and some salts stay liquid below freezing, with the polymer network helping but not fully solving this.New Atlas: Technology-Innovation-Outdoor News: “The gels also have to release heat on cue, because some salts stay liquid even after the temperature drops low enough to solidify them. The polymer network helps, but how it does so isn't well understood.”
SupportedThe authors propose AI and simulation for new polymer-salt combinations, suggest salt blends with tunable melting points, and aim for a tough, recyclable material lasting years in buildings.New Atlas: Technology-Innovation-Outdoor News: “the authors propose the use of simulation and AI to predict which polymer dissolves in which salt. They also suggest salt blends with adjustable melting points... The goal, they say, is to have a tough, recyclable material that holds up for years inside our buildings.”