Researchers develop sustainable strategy to manipulate interfacial heat transfer for eco-friendly cooling applications

Researchers on the Faculty of Engineering of the Hong Kong College of Science and Expertise (HKUST) have developed a sustainable and controllable technique to control interfacial warmth switch, paving the best way for bettering the efficiency of eco-friendly cooling in varied functions reminiscent of electronics, buildings and photo voltaic panels.

The workforce’s analysis work, titled “Direct Observation of Tunable Thermal Conductance at Solid/Porous Cystalline Solid Interfaces Induced by Water Adsorbates,” was just lately published in Nature Communications. Led by Prof. Zhou, the workforce included his Ph.D. college students Wang Guang, Fan Hongzhao, and Li Jiawang, in addition to Affiliate Head of the Division of Mechanical and Aerospace Engineering at HKUST Prof. Li Zhigang.

As demand for efficient cooling options continues to develop as a result of rising world temperature, scientists worldwide have been actively exploring energy-saving cooling applied sciences which might be simpler. In comparison with lively cooling, which completely will depend on energy consumption to function, passive cooling depends on pure processes and design rules to cut back warmth and preserve a cushty temperature with low or no vitality consumption. This method has subsequently generated large curiosity amongst researchers because of its eco-friendly nature and zero-electricity attribute.

One rising discipline of examine is passive cooling utilizing metal-organic frameworks (MOFs), that are porous supplies that may seize water vapor from the air and be used to extend vitality effectivity in room temperature house cooling functions.

Nonetheless, MOFs sometimes exhibit low thermal conductivitymaking them poor thermal conductors. Furthermore, the presence of adsorbed water molecules in MOFs additional reduces their efficient thermal conductivity. This limitation leaves little room for manipulating the intrinsic thermal transport properties of MOFs to boost their cooling efficiency.

To deal with the problem, researchers worldwide have turned their consideration to the interfacial warmth dissipation between MOFs and the supplies they arrive into contact with. Numerous approaches, together with the usage of adhesion layers, nanostructures, chemical modification, and self-assembled monolayers, have been employed to boost the interfacial thermal conductance (ITC). Nonetheless, synthesizing or fabricating buffer layers with exact atomic management is a difficult job, limiting the potential functions of those strategies.

Of their pioneering work, the analysis workforce led by Prof. Zhou Yanguang from the Division of Mechanical and Aerospace Engineering at HKUST launched a sustainable and controllable technique to control interfacial warmth switch between the contacted substrate and typical MOFs by using a water adsorption course of.

Via complete frequency-domain thermoreflectance (FDTR) measurements and molecular dynamics (MD) simulations, they’ve demonstrated a outstanding enchancment in ITC between the contacted substrate and MOFs. The ITC was elevated from 5.3 MW/m²Ok to 37.5 MW/m²Ok, representing an enhancement of roughly 7.1 occasions. Efficient enhancements are additionally noticed in different Au/MOF methods.

The analysis workforce attributes this enchancment to the formation of dense water channels facilitated by the adsorbed water molecules inside MOFs. These channels function extra thermal pathways, considerably enhancing thermal vitality switch throughout the interfaces.

Additional evaluation utilizing the frequency area direct decomposition technique developed by the workforce discovered that the adsorbed water not solely prompts the high-frequency vibrations, but additionally will increase the overlap of vibrational density of states between the substrate and MOF which boosts the thermal vitality dissipation from the substrate to MOF, highlighting the bridge impact of the adsorbed water molecules.

“This innovative study not only provides new insights into thermal transport across MOFs and other materials, but also holds great promise for enhancing the performance of cooling applications involving MOFs. By leveraging the water adsorption process, our team has achieved a breakthrough in manipulating interfacial heat transfer, paving the way for more efficient cooling technologies,” stated Prof. Zhou.