Bio-PCM Panels Composed of Renewable Materials Interact with Solar Heating Systems for Building Thermal Insulation

This article aims to present the feasibility of storing thermal energy in buildings for solar water heating while maintaining the comfort environment for residential buildings.Our contribution is the creation of insulating composite panels made of bio-based phase change materials(bio-PCM is all from coconut oil),cement and renewable materials(treated wood fiber and organic clay).The inclusion of wood fibers improved the thermal properties;a simple 2%increase of wood fiber decreased the heat conductivity by approximately 23.42%.The issues of bio-PCM leakage in the cement mortar and a roughly 56.5%reduction in thermal conductivity with bio-PCM stability in composite panels can be resolved by treating wood fibers with an adjuvant by impregnating them in bio-PCM in the presence of the treated clay generated.Clay and wood fiber were treated with adjuvants that are both biological and environmentally acceptable,as confirmed by FTIR spectroscopy.The heat transfer bench(DIDATEK)showed a decrease in thermal conductivity.By using differential scanning calorimetric(DSC)analysis,the investigation of thermal stability and enthalpy during two heating cycles of pure bio-PCM and composite bio-PCM was validated.The novel renewable material was used to create composite panels for the trial prototype,which took the shape of a component attached to the solar heating system,33.57%less heat was lost,according to the heat transfer research.The outcomes demonstrated the possibility of replacing traditional electric water heating in residential buildings with solar water heating systems.

Effects of Cationic Surfactant on Fresh and Hardened Properties of Cement-Based Mortar

The objective of this study is to analyze the effects of using surfactant(CTAB)and cellulose nanofibers(NFC)as an admixture in cement mortars.We examined composite properties as porosity,compression energy,thermal conductivity and hydration.The results showed that with the addition of 0.7%by weight of NFC per emulsion in the presence of a cationic surfactant(CTAB).The new material produced presented a dry porosity between 4.7%and 4.4%,compressive strength between 9.8 and 22.9 MPa,and thermal conductivity between 0.95 and 2.25 W·m^(−1)·K^(−1).Thus we show better mechanical and thermal performance than that traditional Portland cement mortar with a density similar.In addition,the mortar made by emulsion of ordinary portland cement,cellulose nanofiber and organophilic clay(OC)treated with cetyltrimethylammonium bromide(CTAB)obtained has good resistance under high temperature and water,as well as excellent thermal insulation performance under high temperature and humidity conditions.This study verified that the presence of NFC promotes hydration,leading to the production of more calcium silicate and portlandite gel.

Stabilization and Evaluation of Modified Nanofiber Flour Wood on the Properties of Cement-Baszd Mortar

The influence of nanofiberwood on the properties of the fresh condition of cement based mortars is not known in detail,despite recent advances in nanocellulose technology and it is related composite materials.Nanofiber wood from industrial waste,produced by high-pressure homogenization,was used as cement partial replacement for cement paste at a content ranging from 0%to 2%by weight of cement.The effect of the nanofiber wood content on the porosity,the compressive strength and the degree of hydration of the cement was investigated.Results have shown an improvement in the compressive strength by more than 50%with 1%of added fiber wood.The chemical modification of nanofibers wood by grafting of chains alkyls in their surfaces can reduce the quantity of water absorbed by the sample.The addition of an anionic additive(SDBS)in the water of mixing improves of more the surface of samples by minimizing the size of pores by emulsion effect,from where the absorption of water reduces.The degree of hydration of the cement has increased with the cellulose content containing nanofibrils.The analyze revealed that the presence of nanofiber wood favored the hydration of the cement by producing more calcium silicate gel and portlandite,probably the main reason for this improvement in compressive strength.

Influence and Dispersion of Nanofiber of Wood Modified on Properties of Cement Based Mortars

Wood nanofibers from industrial waste have been used as polymeric material to reinforce the cement paste to a content of up to 2%by weight of cement.The effect of the wood nanofibre content on the porosity,the compressive strength and the degree of hydration of the cement was studied.The results showed an improvement in compressive strength of over 50%with 1%of added fiberwood.Chemical modification of nanofiber wood by grafting alkyl chains to their surface can reduce the amount of water absorbed by the sample.Addition of an anionic additive(SDBS)to the mixing water improves the surface of the samples more and more by minimizing the pore size by emulsion effect,hence the water absorption decreases.The degree of hydration of the cement increased with the cellulose content containing nanofibrils.The analysis revealed that the presence of nanofibers favored the hydration of the cement by producing more calcium silicate gel and portlandite,probably the main reason for this improvement in compressive strength.

Some Advances in Applications of Lattice Boltzmann Method for Complex Thermal Flows

Over the past two decades,there have been enormous advances in lattice Boltzmann(LB)numerical simulation and modelling.The lattice Boltzmann method has become a practical and promising tool for many fluid problems.A majority of recent studies have relied on numerical computations of isothermal flows.However,much less efforts have been devoted to complex thermal flows,such as flows in porous media subjected to external magnetic force,flows with temperature-dependent properties.In this paper,an overview is made based on some accomplishments in these numerical endeavours.Along with the paper’s sections,the state-of-the-art trend and the LBM advances in modelling and in computational aspects for specific classes of problems of major interest will be fully touched on.Concluding remarks are given and the axis of our future studies will be traced.