The effect of surface entropy on the heat of non-wetting liquid intrusion into nanopores

On-demand access to renewable and environmentally friendly energy sources is critical to address current and future energy needs. To achieve this, the development of new mechanisms of efficient thermal energy storage (TES) is important to improve the overall energy storage capacity. Demonstrated here is the ideal concept that the thermal effect of developing a solid−liquid interface between a non-wetting liquid and hydrophobic nanoporous material can store heat to supplement current TES technologies. The fundamental macroscopic property of a liquid’s surface entropy and its relationship to its solid surface are one of the keys to predict the magnitude of the thermal effect by the development of the liquid−solid interface in a nanoscale nvironment driven through applied pressure. Demonstrated here is this correlation of these properties with the direct measurement of the thermal effect of non-wetting liquids intruding into hydrophobic nanoporous materials. It is shown that the model can resonably predict the heat of intrusion into rigid mesoporous silica and some microporous zeolite when the temperature dependence of the contact angle is applied. Conversely, intrusion into flexible microporous metal−organic frameworks requires further improvement. The reported results with further development have the potential to lead to the development of a new supplementary method and mechanim for TES

Energy consumption determination of the heat storage device based on the phase change material depending on the temperature ranges

The work concerns determining the energy performance of the heat storage device based on the phase change material for the solar dish Stirling unit. Experimental studies were performed with the heat storage material, made of the eutectic metal alloy Mg-51%Zn. The energy characteristics are determined by mathematical analysis of theexperimental data and simulation of the process of cooling the heat storage

Exceptionally large and controlled effect of negative thermal expansion in porous heterogeneous lyophobic systems.

International audienceNegative thermal expansion (NTE) is the process in which a system decreases its size upon heating and increases it upon cooling. NTE effect is unusual and useful for a great number of practical applications in the fields of electronics, medicine, mechanics, etc. In this work, NTE effect is experimentally investigated for three porous Heterogeneous Lyophobic Systems (HLS), associating water and two grafted mesoporous silicas or the microporous metal–organic framework ZIF-8. Considerable NTE effect, more than 1 order of magnitude higher than best-known materials, is observed for these systems. Additionally, it is demonstrated that for HLS, the temperature range in which NTE takes place is easily controlled by basic characteristics of the porous solid such as pore size distribution

Turning Molecular Springs into Nano-Shock Absorbers: The Effect of Macroscopic Morphology and Crystal Size on the Dynamic Hysteresis of Water Intrusion-Extrusion into-from Hydrophobic Nanopores.

Funder: Engineering and Physical Sciences Research CouncilControlling the pressure at which liquids intrude (wet) and extrude (dry) a nanopore is of paramount importance for a broad range of applications, such as energy conversion, catalysis, chromatography, separation, ionic channels, and many more. To tune these characteristics, one typically acts on the chemical nature of the system or pore size. In this work, we propose an alternative route for controlling both intrusion and extrusion pressures via proper arrangement of the grains of the nanoporous material. To prove the concept, dynamic intrusion-extrusion cycles for powdered and monolithic ZIF-8 metal-organic framework were conducted by means of water porosimetry and in operando neutron scattering. We report a drastic increase in intrusion-extrusion dynamic hysteresis when going from a fine powder to a dense monolith configuration, transforming an intermediate performance of the ZIF-8 + water system (poor molecular spring) into a desirable shock-absorber with more than 1 order of magnitude enhancement of dissipated energy per cycle. The obtained results are supported by MD simulations and pave the way for an alternative methodology of tuning intrusion-extrusion pressure using a macroscopic arrangement of nanoporous material