Wei Cai

The incorporation of phase change material (PCM) can enhance wall thermal performance and indoor thermal comfort, but practical applications still face challenges related to high costs and potential leakage issues. In this study, a novel dual-biomass-based shape-stabilized PCM (Bio-SSPCM) was proposed, wherein waste cooking fat and waste reed straw were, respectively, incorporated as the PCM substance and supporting material. The waste fat (lard) consisted of both saturated and unsaturated fatty acid glycerides, exhibiting a melting point about 21.2–41.1 °C and a melting enthalpy value of 40 J/g. Reed straw was carbonized to form a sustainable porous biochar supporting matrix, which was used for the vacuum adsorption of waste fat. The results demonstrate that the as-prepared dual-Bio-SSPCM exhibited excellent thermal performance, characterized by a latent heat capacity of 25.4 J/g. With the addition of 4 wt% of expanded graphite (EG), the thermal conductivity of the composite PCM reached 1.132 W/(m·K), which was 5.4 times higher than that of the primary lard. The thermal properties of the Bio-SSPCM were characterized using an analog T-history method. The results demonstrated that the dual-Bio-SSPCM exhibited exceptional and rapid heat storage and exothermic capabilities. The dual-Bio-SSPCM, prepared from waste cooking fat and reed straw, can be considered as environmentally friendly construction material for energy storage in line with the principles of the circular economy.

Phase change emulsions (PCMEs) are always identified as potential working fluids that could be used to reduce circulating pump energy consumption in chill water air conditioning systems. But how PCME behaves in a fin-and-tube heat exchanger is still unclear, which limited the application of such material. The paper focused on experimental studies of performance of a novel PCME, named as PCE-10, in a fin-and-tube heat exchanger. The research analyzed heat transfer and flow behavior in fin-and-tube heat exchangers and the experimental results are compared with numerical studies published. Both studies showed that PCE-10 had its advantages as a cold storage medium, as PCE-10 did help to improve the heat transfer rate of heat exchanger by factor of 1.1–1.3 at the same flow rate compared with water.

This work focuses on computing the homogenized elastic properties of rocks from 3D micro-computed-tomography (micro-CT) scanned images. The accurate computation of homogenized properties of rocks, archetypal random media, requires both resolution of intricate underlying microstructure and large field of view, resulting in huge micro-CT images. Homogenization entails solving the local elasticity problem computationally which can be prohibitively expensive for a huge image. To mitigate this problem, we use a renormalization method inspired scheme, the hierarchical homogenization method, where a large image is partitioned into smaller subimages. The individual subimages are separately homogenized using periodic boundary conditions, and then assembled into a much smaller intermediate image. The intermediate image is again homogenized, subject to the periodic boundary condition, to find the final homogenized elastic constant of the original image. An FFT-based elasticity solver is used to solve the associated periodic elasticity problem. The error in the homogenized elastic constant is empirically shown to follow a power law scaling with exponent -1 with respect to the subimage size across all five microstructures of rocks. We further show that the inclusion of surrounding materials during the homogenization of the small subimages reduces error in the final homogenized elastic moduli while still respecting the power law with the exponent of -1. This power law scaling is then exploited to determine a better approximation of the large heterogeneous microstructures based on Richardson extrapolation

Supramolecular interaction is a kind of intermolecular interaction with molecular recognition ability. Based on molecular recognition, the design, synthesis, and assembly of novel supramolecular functional materials will provide theoretical guidance and new application systems for analytical science. It has made great contributions to the common development of life sciences, materials sciences, and environmental sciences. This article aims at the application of supramolecular nanomaterial adsorbents in indoor volatile organic pollutants control in hot and humid regions. This article sets up three experimental groups and a control group. The experimental group is to apply supramolecular nanomaterial adsorbents to Northeast China. Among the volatile organic pollutants in cold regions, the experimental group 2 applied the supramolecular nanomaterial adsorbents to indoor volatile organic pollutants in the humid and hot regions of the south. The experimental three groups of supramolecular nanomaterial adsorbents were applied in temperate environments. The control group applied general materials to study the effect of purification, considered purification time, efficiency, and economic benefits, and used mathematical statistics and mathematical analysis to classify and analyze and use big data. Use these methods to fit the data. Experimental data shows that the application of supramolecular nanomaterial adsorbents in indoor volatile organic pollutants control in hot and humid areas has a good effect and can effectively achieve the purpose of purifying organic pollutants. Experimental data shows that the application of supramolecular nanomaterial adsorbents in indoor volatile organic pollutants control in hot and humid areas has a broad application prospect. Its purification efficiency of organic pollutants has increased by about 23.5% and its economic efficiency has increased by about 21.3%. The application plays a guiding rolein the purification of volatile organic pollutants.