Thermal Performance Analysis of Plaster Reinforced with Raffia Vinifera Particles for Use as Insulating Materials in Building

The present study focuses on the formulation of new composite consisting of plaster and raffia vinifera particle (RVP) with the purpose to reducing energy consumption. The aim of this study is to test this new compound as an insulating eco-material in building in a tropical climate. The composites samples were developed by mixing plaster with raffia vinifera particles (RVP) using three different sizes (1.6 mm, 2.5 mm and 4 mm). The effects of four different RVP incorporations rates (i.e., 0wt%, 5wt%;10wt%;15wt%) on physical, thermal, mechanicals properties of the composites were investigated. In addition, the use of the raffia vinifera particles and plaster based composite material as building envelopes thermal insulation material is studied by the habitable cell thermal behavior instrumentation. The results indicate that the incorporation of raffia vinifera particle leads to improve the new composite physical, mechanical and thermal properties. And the parametric analysis reveals that the sampling rate and the size of raffia vinifera particles are the most decisive factor to impact these properties, and to decreases in the thermal conductivity which leads to an improvement to the thermal resistance and energy savings. The best improvement of plaster composite was obtained at the raffia vinifera particles size between 2.5 and 4.0 mm loading of 5wt% (C95P5R) with a good ratio of thermo-physical-mechanical properties. Additionally, the habitable cell experimental thermal behavior, with the new raffia vinifera particles and plaster-based composite as thermal insulating material for building walls, gives an average damping of 4°C and 5.8°C in the insulated house interior environment respectively for cold and hot cases compared to the outside environment and the uninsulated house interior environment. The current study highlights that this mixture gives the new composite thermal insulation properties applicable in the eco-construction of habitats in tropical environments.

Research on thermal insulation materials properties under HTHP conditions for deep oil and gas reservoir rock ITP-Coring

Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability,resulting in distorted resource assessments.The development of in situ temperaturepreserved coring(ITP-Coring)technology for deep reservoir rock is urgent,and thermal insulation materials are key.Therefore,hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials)were proposed as thermal insulation materials.The materials properties under coupled hightemperature and high-pressure(HTHP)conditions were tested.The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased;additionally,increasing temperature accelerated the process.High temperatures directly caused the thermal conductivity of the materials to increase;additionally,the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity.High temperatures weakened the matrix,and high pressures destroyed the HGM,which resulted in a decrease in the tensile mechanical properties of the materials.The materials entered the high elastic state at 150℃,and the mechanical properties were weakened more obviously,while the pressure led to a significant effect when the water absorption was above 10%.Meanwhile,the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86%at 100℃ and 100 MPa,respectively,which meet the application requirements of the self-designed coring device.Finally,K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100℃ and 100 MPa.To further improve the materials properties,the interface layer and EP matrix should be optimized.The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.

Research for Optimizing Porosity of Porous Thermal-insulating Materials

With the energy crisis and ecological environment deterioration, porous thermal-insulating materials become an advanced research hotspot, and the influence of pore distribution cannot be ignored. The mathematical model is established basing on the heat transfor theory, regarding the minimum heat flux density as the objective function, the constant total porosity as a constraint condition, using the BFGS method to optimize the pore distribution. The results show that when the heat flux is the minimum, in the case of the fixed total porosity, the high temperature zone has high porosity, the low temperature zone has low porosity; the maximal fluctuating amplitude of porosity between the adjacent discrete points has great impact on the thermal insulating performanee, the greater the fluctuating amplitude, the better the thermal insulating ability. After calculating the temperature field of the corresponding physical model, it can be found that the temperature gradient is non-uniform, the temperature gradient of the high temperature zone is steep, and that of the low temperature zone is gentle. These results have guiding significance for preparation of porous thermal-insulating materials.

Research on non-steam-cured and non-fired fly-ash thermal insulating materials

A thermal insulating material is synthesized via a non-steam-cured and non-fired route by using fly-ash, sorel cement and hydrogen peroxide solution as raw material. Properties such as apparent density, compressive strength, bending strength, thermal conductivity, water resistance, and thermal tolerance of this matrial are studied, some influencing factors on its performance discussed. This material has an apparent density of 360 kg/m^3, a compressive strength of 1.86 MPa, a thermal conduction coefficient of 0.072 W/（m·K）, a softening coefficient of 0.55, and a thermal tolerant temperature of 300 ℃. Test results show that this material is light in weight, of high strength, and good thermal insulation. In addition, neither steam-curing nor sintering is needed in producing it. Further more, large amount of fly ash is used in this material, making it a low cost and environment-friendly building material.

Preparation of Nanoporous Thermal Insulating Materials and Their Application as Ladle Linings

The nanoporous thermal insulating material was prepared by using fumed silica,SiC powder and glass fiber as starting materials,the appropriate thickness of the nanoporous thermal insulating material lined in ladle was discussed by the simulation method,and the effect of its application as ladle lining was investigated.The results show that the thermal conductivity of the nanoporous thermal insulating material prepared in composition of fumed silica： SiC powder： glass fiber =75： 20：5 （in mass） is 0.023 W · m^-1 · K^-1 at 1 000 ℃,the appropriate thickness of the nanoporous thermal insulating material lined in ladle is ≤ 5 mm and the average temperature of the ladle outside surface when lined with the nanoporous thermal insulating material is 95 ℃ lower than that with the ordinary thermal insulating material.

Thermally insulating and fire-retardant bio-mimic structural composites with a negative Poisson's ratio for battery protection

Battery safety has attracted considerable attention worldwide due to the rapid development of wearable electronics and the steady increase in the production and use of electric vehicles.As battery failures are often associated with mechanical-thermal coupled behaviors,protective shielding materials with excellent mechanical robustness and flame-retardant properties are highly desired to mitigate thermal runaway.However,most of the thermal insulating materials are not strong enough to protect batteries from mechanical abuse,which is one of the most critical scenarios with catastrophic consequences.Here,inspired by wood,we have developed an effective approach to engineer a hierarchical nanocomposite via self-assembly of calcium silicate hydrate and polyvinyl alcohol polymer chains(referred as CSH wood).The versatile protective material CSH wood demonstrates an unprecedented combination of light weight(0.018 g cm-3),high stiffness(204 MPa in the axial direction),negative Poisson's ratio(-0.15),remarkable toughness(6.67×105 J m-3),superior thermal insulation(0.0204 W m-1 K-1 in the radial direction),and excellent fire retardancy(UL94-V0).When applied as a protective cover or a protective layer within battery packages,the tough CSH wood can resist high-impact load and block heat diffusion to block or delay the spread of fire,therefore significantly reducing the risk of property damage or bodily injuries caused by battery explosions.This work provides new pathways for fabricating advanced thermal insulating materials with large scalability and demonstrates great potential for the protection of electronic devices.

Porous high-entropy rare-earth phosphate(REPO_(4),RE=La,Sm,Eu,Ce,Pr and Gd)ceramics with excellent thermal insulation performance via pore structure tailoring

Thermal insulation materials play an increasingly important role in protecting mechanical parts functioning at high temperatures.In this study,a new porous high-entropy(La_(1/6)Ce_(1/6)Pr_(1/6)Sm_(1/6)Eu_(1/6)Gd_(1/6))PO_(4)(HE(6RE_(1/6))PO_(4))ceramics was prepared by combining the high-entropy method with the pore-forming agent method and the effect of different starch contents(0–60vol%)on this ceramic properties was systematically investigated.The results show that the porous HE(6RE_(1/6))PO_(4)ceramics with 60vol%starch exhibit the lowest thermal conductivity of 0.061 W·m^(-1)·K^(-1)at room temperature and good pore structure stability with a linear shrinkage of approximately1.67%.Moreover,the effect of large regular spherical pores(>10μm)on its thermal insulation performance was discussed,and an optimal thermal conductivity prediction model was screened.The superior properties of the prepared porous HE(6RE_(1/6))PO_(4)ceramics allow them to be promising insulation materials in the future.

Effects of Al_(2)O_(3)-SiO_(2) Raw Material Types on Properties of Anorthite Based Insulation Refractories

To optimize their Al_(2)O_(3)-SiO_(2) raw materials,anorthite based insulation refractories were prepared by the in-situ sintering process combined with the foaming method after sintering at 1350℃for 3 h,using green and pollution-free kaolin,kyanite,andalusite and sillimanite as Al_(2)O_(3)-SiO_(2) raw materials,respectively,and industrial CaCO_(3) as the CaO source.Effects of Al_(2)O_(3)-SiO_(2) raw material types on the physical properties,phase composition and microstructure were investigated.The results are as follows.All samples prepared by different Al_(2)O_(3)-SiO_(2) raw materials have hexagonal flake anorthite and a small amount of mullite and corundum.Their bulk density and thermal conductivity decrease in the order of using kaolin,andalusite,kyanite and sillimanite as the Al_(2)O_(3)-SiO_(2) raw material,but their apparent porosity increases.Moreover,in the sample with kaolin,the bonding between anorthite crystals on the pore walls is closer than that of the other samples,which is conducive to increasing the cold crushing strength.The bonding between anorthite crystals on pore walls gradually decreases in the order of using kyanite,andalusite and sillimanite as the Al_(2)O_(3)-SiO_(2) raw material,thus their cold crushing strength decreases accordingly.In comprehensive consideration,the properties of the sample from kyanite are the optimal.Its apparent porosity,thermal conductivity and cold crushing strength are 84.6%,0.141 W·m^(-1)·K^(-1) and 1.89 MPa,respectively.

Numerical and experimental evaluation for density-related thermal insulation capability of entangled porous metallic wire material

Entangled porous metallic wire material(EPMWM)has the potential as a thermal insulation material in defence and engineering.In order to optimize its thermophysical properties at the design stage,it is of great significance to reveal the thermal response mechanism of EPMWM based on its complex structural effects.In the present work,virtual manufacturing technology(VMT)was developed to restore the physics-based 3D model of EPMWM.On this basis,the transient thermal analysis is carried out to explore the contact-relevant thermal behavior of EPMWM,and then the spiral unit containing unique structural information are further extracted and counted.In particular,the thermal resistance network is numerically constructed based on the spiral unit through the thermoelectric analogy method to accurately predict the effective thermal conductivity(ETC)of EPMWM.Finally,the thermal diffusivity and specific heat of the samples were obtained by the laser thermal analyzer to calculate the ETC and thermal insulation factor of interest.The results show that the ETC of EPMWM increases with increasing temperature or reducing density under the experimental conditions.The numerical prediction is consistent with the experimental result and the average error is less than 4%.

Analysis of the Performances of a New Type of Alumina Nanocomposite Structural Material Designed for the Thermal Insulation of High-Rise Buildings

The sol-gel method is used to prepare a new nano-alumina aerogel structure and the thermal properties of this nanomaterial are investigated comprehensively using electron microscope scanning,thermal analysis,X-ray and infrared spectrometer analysis methods.It is found that the composite aerogel alumina material has a multi-level porous nano-network structure.When employed for the thermal insulation of high-rise buildings,the alumina nanocomposite aerogel material can lead to effective energy savings in winter.However,it has almost no energy-saving effect on buildings where energy is consumed for cooling in summer.

Preparation and Properties of TiO2-Coated Hollow Glass Microspheres as Thermal Insulation Materials for Energy-Saving Buildings

A hollow glass microsphere(HGM)/TiO2 composite hollow sphere was successfully prepared via a simple precipitation method.The TiO2 coating layers grew on the surface of the HGMs that range from 20 to 50μm in diameter as nanoparticles with the formation of the SiO Ti bonds.The growth mechanism accounting for the formation of the TiO2 nanolayers was proposed.The morphology,composition,thermal insulation properties,and visible-near infrared(VIS-NIR)refl ectance of the HGMs/TiO2 composite hollow spheres were characterized.The VIS-NIR reflectance of the HGMs/TiO2 composite hollow spheres increased by more than 30%compared to raw HGMs.The thermal conductivity of the particles is 0.058 W/(m K).The result indicates that the VIS-NIR reflectance of the composite hollow spheres is strongly influenced by the coating of TiO2.The composite hollow spheres were used as the main functional filler to prepare the organic-inorganic composite coatings.The glass substrates coated by the organic-inorganic coatings had lower thermal conductivity and higher near infrared reflectivity.Therefore,the HGMs/TiO2 composite hollow spheres can reflect most of the solar energy and effectively keep out the heat as a thermal insulation coating for energy-saving constructions.

Preparation of Ultra-light Xonotlite Thermal Insulation Material Using Carbide Slag

Using carbide slag as the calcareous materials, xonotlite thermal insulation material was successfully prepared via dynamic hydrothermal synthesis. The experimental results show that the xonotlite thermal insulation material is made up of large numbers of ＂chestnut bur shape＂ particles. Optimum conditions of calcination temperature of carbide slag, synthesis reaction temperature and time, stirring rate, CaO/SiO2 mol ratio, water/solid weight ratio, amount of fiberglass, molding pressures, dryness temperatures and the presence of dispersant （glycol and polyvinyl alcohol） favor the preparation of xonotlite thermal insulation material. The evaluation of xonotlite thermal insulation material reveals that the product is ultra-light and excellent in physical performances. Such a little amount of impurities in carbide slag has no effect on the phase, morphology, stability at high temperature and physical performances of products.

Carbon foams prepared from coal tar pitch for building thermal insulation material with low cost

A new approach is provided to resolve the large-scale applications of coal tar pitch. Carbon foams with uniform pore size are prepared at the foaming pressure of normal pressure using coal tar pitch as raw materials. The physical and chemical performance of high softening point pitch(HSPP) can be regulated by vacuumizing owing to the cooperation of vacuumizing and polycondensation. Results indicate that the optimum softening point and weight ratio of quinoline insoluble are about 292℃ and 65.7%, respectively. And the optimum viscosity of HSPP during the foaming process is distributed in the range of 1000-10000 Pa·s. The resultant carbon foam exhibits excellent performance, such as uniform pore structure, high compressive strength(4.7 MPa), low thermal conductivity(0.07 W·m^(-1) ·K^(-1)), specially, it cannot be fired under the high temperature of 1200 ℃.Thus, this kind of carbon foam is a potential candidate for thermal insulation material applied in energy saving building.

High-stability temperature control and frequency-domain analysis of sandwich-like insulation design based on phase change materials for satellite thermal management

High-stability thermal management is critical for the measurements of high sensitivity for temperature, but also challenging because any small thermal disturbances could lead to unacceptable temperature fluctuations. The present work delivers a design for passive temperature control, customized for a component in the satellites for gravitational wave detection. A novel sandwichlike structure is proposed with the configurations of proper materials, consisting of a layer of insulation material and two layers of nanocomposite phase change materials, bringing an integration of heat insulation and absorption/storage. Its performance is examined using an improved thermal network model and the revised transfer function method(TFM). The basic results of the two methods are validated by present COMSOL simulations and available numerical and experimental data in the literature. An effective reduction of temperature fluctuation is achieved to the scale of 0.1 K, even under two thermal disturbances from different directions: a radiative heat flux of 20 W m~(-2)(inside) and a temperature fluctuation of about 20 K(outside). Moreover,the TFM is employed to analyze the effects of the frequency of thermal disturbance: excellent damping performance is obtained for over 3.2 mHz and the underlying mechanism is discussed. Overall, the present design is expected to be combined with active temperature control to explore more possible ways for temperature control with higher stability.

Effect of Pyrophyllite Addition on Properties of Lightweight Insulation Refractory Materials

To solve the problem of over-high density of lightweight insulation refractory bricks prepared with fly ash, new lightweight insulation refractory materials with density 〈 0. 89 g · cm^-3 were .synthesized using pyrophyl-lite, .fly ash, and Suzhou clay as the main starting materials and saw dast as the pore forming substance, and controlling the addition of the pyrophyllite （20%, 30% , and 40% by mass ） and the treating temperature （1 250, 1 300, 1 350, and 1 400 ℃ ）. The synthesized materials were characterized by the XRD, SEM and the thermal conductivity measuring in.strument. The results show at pyrophyllite addition of 30% and treat temperature of l 400 ℃ , the material can achieve linear shrinkage of 6. 6%, apparent porosity of 57%, bulk density of 0. 75 g · cm^-3, compressive strength of 2.7 MPa, and thermal conductivity at 350 ℃ of 0. 152 -0. 216 W·（ m·K）^-1.This indicates that the pyrophyllite decomposition at high temperatures forms mullite and amorphous quartz introducing volume expansion, which counteracts some shrinkage at high temperatures. So it is feasible to use pyrophyllite, fly ash waste and clay to prepare lightweight insulation refractory materials.

Light Weight Insulating Material Prepared from Rice Husk

Pakistan is at 12th number in the rank of rice production countries. Along with the production of 4,500 thousand metric tons of rice enormous quantity of rice husk is left as waste. Light weight thermal insulating material was prepared from rice husk. Epoxy resin was used as a binder and was mixed with rice husk to give it strength, the sample was compressed at 7000 psi to produce cylindrical shape block. The thermal conductivity of the sample A, B, C and D of thickness 1, 2, 3 and 4 cm respectively was measured 0.0241, 0.0240, 0.239 and 0.0219 watts/m-k, which was lower than the common mortar by 51.74%, therefore it could be used in buildings and roof as an insulating material. This would be a suitable alternative which would not only save energy but also solve the environmental disposal problems as well. The results are very promising and we hope insulation material prepared would be useable in hot climate regions like Pakistan in buildings to prevent heat transfer.

Hollow glass microspheres/silicone rubber composite materials toward materials for high performance deep in-situ temperaturepreserved coring

Deep petroleum resources are stored under high temperature and pressure conditions,with the temperature having a significant influence on the properties of rocks.Deep in-situ temperature-preserved coring(ITP-coring)devices were developed to assess deep petroleum reserves accurately.Herein,hollow glass microspheres(HGMs)/silicone rubber(SR)composites that exhibit excellent thermal insulation properties were prepared as thermal insulation materials for deep ITP-coring devices.The mechanism and process of heat transfer in the composites were explored,as well as their other properties.The results show that the HGMs exhibit good compatibility with the SR matrix.When the volume fraction of the HGMs is increased to 50%,the density of the HGMs/SR composites is reduced from 0.97 to 0.56 g/cm^(3).The HGMs filler introduces large voids into the composites,reducing their thermal conductivity to 0.11 W/m·K.The addition of HGMs into the composites further enhances the thermal stability of the SR,wherein the higher the HGMs filler content,the better the thermal stability of the composites.HGMs significantly enhance the mechanical strength of the SR.HGMs increase the compressive strength of the composites by 828%and the tensile strength by 164%.Overall,HGMs improve the thermal insulation,pressure resistance,and thermal stability of HGMs/SR composites.

Experimental study on the influence of temperature and humidity on the thermal conductivity of building insulation materials

At present,thermal conductivity is usually taken as a constant value in the calculation of building energy con-sumption and load.However,in the actual use of building materials,they are exposed to the environment with continuously changing temperature and relative humidity.The thermal conductivity of materials will inevitably change with temperature and humidity,leading to deviations in the estimation of energy consumption in the building.Therefore,in this study,variations in the thermal conductivity of eight common building insulation materials(glass wool,rock wool,silica aerogel blanket,expanded polystyrene,extruded polystyrene,phenolic foam,foam ceramic and foam glass)with temperature(in the range of 20-60°C)and relative humidity(in the range of 0-100%)were studied by experimental methods.The results show that the thermal conductivity of these common building insulation materials increased approximately linearly with increasing temperature with maxi-mum growth rates from 3.9 to 22.7%in the examined temperature range.Due to the structural characteristics of materials,the increasing thermal conductivity of different materials varies depending on the relative humidity.The maximum growth rates of thermal conductivity with humidity ranged from 8.2 to 186.7%.In addition,the principles of selection of building insulation materials in different humidity regions were given.The research re-sults of this paper aim to provide basic data for the accurate value of thermal conductivity of building insulation materials and for the calculation of energy consumption.

Research on Construction Process of EPS in the Thermal Insulation Building

In order to improve the efficiency of EPS integral thermal insulation building design and optimize the construction process of insulation construction, this paper uses experiment parts and simulation form to design the thermal insulation construction process, and evaluates the effect of heat preservation. Based on the finite element theory this paper designs adding process of insulation material EPS in the thermal insulation layer, and establishes the radiation heat conduction model of EPS material, finally obtains the solid heat conduction equation. Finally this paper uses ANSYS software to do simulation on the strength and temperature of EPS construction, and evaluates the quality of construction works, which provides technical reference for the design of integrated thermal insulation buildings.

Influence of materials’hygric properties on the hygrothermal performance of internal thermal insulation composite systems

Internal thermal insulation composite system(ITICS)can be an important measure for the energy-saving retrofitting of buildings.However,ITICS may cause harmful effects on the hygrothermal performance of building envelopes.This work investigated the influence of the materials’hygric properties on the hygrothermal perfor-mance of a typical ITICS in different climate conditions in China.Two base wall materials,the traditional concrete and a new type aerated concrete,were tested and compared for their hygric properties firstly.The influence of the hygroscopicity of exterior plasters,the permeability of insulation materials and the climate conditions were then analyzed with WUFI simulations.The hygrothermal performance was evaluated with consideration of the total water content(TWC)of the walls and the moisture flux strength,the relative humidity(RH)and the mould growth risk at the interface between the base wall and the insulation layer(B-I interface).The numerical analysis implies that the TWC of internal insulated walls depends mainly on the hygroscopicity of exterior plaster and the wind-driven rain intensity.The upper limits for the water absorption coefficient of exterior plasters used in Bei-jing,Shanghai and Fuzhou are 1e-9,1e-10,1e-10 m^(2)/s respectively.When such limits are guaranteed,a vapour tight system created by using insulation materials with a large vapour resistance factor or adding a vapour barrier can improve the hygrothermal performance of ITICS,especially for concrete walls in cold climate.