Thermal Insulation Of Buildings Research Articles

Building Thermal Insulation Performance and economic benefits

Three different insulating scenarios were investigated using Energy-plus software, to study the effect of using expanded polystyrene boards on building energy consumption at the Libyan Center for Solar Energy Research and Studies. The three insulation scenarios with different polystyrene insulation thicknesses and densities were investigated. Polystyrene total cost, Payback period, total and net money saving using insulation, as well as the percentage gain were calculated for each case in the three investigated scenarios for 50 years. The most money saving scenarios after 50 years is by insulating the building roof and external walls with an average insulation thickness of 7 cm, reaching about 78000 L.D and a tariff of 0.9261 L.D /kWh. While the least money saving is the roof scenario with an insulation thickness of 2.5 cm, reaching more than 29000 L.D and the same tariff. The highest percentage gain values are 76 %, 103 % and1090 % at the roof scenario, 2.5 cm insulation thickness and energy tariffs of 0.15 L.D /kWh, 0.1732 L.D/kWh and 0.9261 L.D/kWh, respectively. While the lowest percentage gain values are about 17.5 %, 35.7 % and 725 % at the wall scenario 10 cm insulation thickness and energy tariffs of 0.15 L.D/kWh, 0.1732 L.D/kWh and 0.9261 L.D/kWh, respectively. the payback period of total insulation cost is significantly dependent on insulation thickness and energy tariff. These results show that low energy tariff (current energy tariff) values economically are not cost effective regarding the payback period. Consequently, prices do not motivate residents to save energy with the use of thermal insulation unless actual energy prices are considered.

Changes in properties of thermal insulations under certain environmental effects

AbstractSaving energy and reducing greenhouse gas emissions is a priority for the construction sector. Heating of buildings requires the burning of fossil fuels, which can be significantly reduced by insulating the building envelope. Nowadays, the thermal insulation of buildings is essential. There are several important, well-known data about most thermal insulation materials, but there is only negligible information about the change of their properties under installation conditions or if they are already exposed to additional stresses due to structural failures and damages. This study aimed to examine the changes in properties of three common thermal insulation materials when installed in a flat roof or facade and exposed to excess moisture due to the damage of waterproofing or façade and/or when exposed to direct strong sunlight.

Historical Evolution and Current Developments in Building Thermal Insulation Materials—A Review

The European Climate Law mandates a 55% reduction in CO2 emissions by 2030, intending to achieve climate neutrality by 2050. To meet these targets, there is a strong focus on reducing energy consumption in buildings, particularly for heating and cooling, which are the primary drivers of energy use and greenhouse gas emissions. As a result, the demand for energy-efficient and sustainable buildings is increasing, and thermal insulation plays a crucial role in minimizing energy consumption for both winter heating and summer cooling. This review explores the historical development of thermal insulation materials, beginning with natural options such as straw, wool, and clay, progressing to materials like cork, asbestos, and mineral wool, and culminating in synthetic insulators such as fiberglass and polystyrene. The review also examines innovative materials like polyurethane foam, vacuum insulation panels, and cement foams enhanced with phase change materials. Additionally, it highlights the renewed interest in environmentally friendly materials like cellulose, hemp, and sheep wool. The current challenges in developing sustainable, high-performance building solutions are discussed, including the implementation of the 6R principles for insulating materials. Finally, the review not only traces the historical evolution of insulation materials but also provides various classifications and summarizes emerging aspects in the field.

The synergistic sintering of ultra-lightweight ceramsite from molybdenum ore tailings, iron ore tailings and waste glass powders: Properties and formation mechanism

Molybdenum ore tailings, iron ore tailings and waste glass powders are important industrial solid wastes, mainly composed of silicate minerals and quartz, which are expected to become alternative resources for inorganic non-metal industrial materials. In this paper, the ultra-lightweight ceramsite was prepared by the synergistic sintering of molybdenum ore tailings, iron ore tailings and waste glass powders according to their characteristics of silicate minerals. The physical and mechanical properties were investigated when the sintering temperature was between 1100 and 1140 °C. The evolution of mineral phases and formation mechanism of pore structure during sintering were studied by XRD, FT-IR, SEM, TG-DSC and HSM. The results showed that in the sintering process, the waste glass powders and the pargasite in iron ore tailings first melted to produce the initial liquid phases. Then the anorthoclase and the quartz in molybdenum ore tailings melted to produce a large amount of liquid phases. These liquid phases covered the gas generated by the oxidation of SiC, thus forming a rich pore structure. At the same time, the [Si2O64−] and Ca2+, Mg2+ in the liquid phases derived from quartz and pargasite melting recrystallized to form diopside, which was conducive to the improvement of mechanical properties of ceramsite. When the raw material ratio of molybdenum ore tailings, iron ore tailings and waste glass powders was 6:2:2 and the sintering temperature was 1120 °C, the pore structure of the ceramsite as prepared was uniform and rich and mostly closed. The density was low and the mechanical propertities were excellent. It has a good application prospect in the field of building thermal insulation and sound insulation.

Compliance to building thermal envelope insulation requirements based on theory of planned behavior (TPB) and procedural justice theory (PJT)

The construction industry plays a crucial role in achieving sustainable development, particularly in the context of energy conservation. addressing the building's optimized energy efficiency is essential, as it accounts for a significant portion of global energy consumption. While many countries have implemented policies related to building energy conservation, the lack of compliance with relevant regulations remains a challenge. However, voluntary self-regulated compliance can be encouraged through flexible approaches that leverage normative influence and equitable governance attributes within the regulatory system. This study evaluates the building contractors' intention to comply with the Building Thermal Envelope Insulation Requirements (BTE-IR), a critical energy conservation measure for buildings. An integrative model combining the Procedural Justice Theory (PJT) and the Theory of Planned Behavior (TPB) was developed to quantitatively investigate individual and social factors influencing compliance with BTE-IR. The study analyzed a sample of 214 Iranian building contractors using Partial Least Squares Structural Equations Modeling (PLS-SEM). The core findings revealed that subjective norms (β = 0.330, p < 0.01) and perceived behavioral control (β = 0.337, p < 0.01) significantly influence intention to comply with BTE-IR. Additionally, the study explored the moderating effects of job satisfaction, job commitment, years of experience, project experience and marital status on the relationships between variables in the research model. These findings can inform construction industry policymakers in developing optimized strategies for self-regulated compliance with BTE-IR and legitimizing the regulatory system for enforcing sustainable practices.

OPTIMIZATION OF HEAT CONSUMPTION IN CENTRAL HEATING SYSTEMS AT COMMERCIAL FACILITIES

Rising energy prices and stricter environmental regulations are exacerbating the problem of inefficient heat consumption in the commercial sector. Central heating systems of office buildings, shopping malls, and industrial complexes are often characterized by excessive thermal energy consumption, which leads to significant economic losses and a negative impact on the natural environment. The purpose of the study is to study the directions and trends of optimization in the field under consideration (taking into account modern technological capabilities, and economic factors). There are disagreements in the professional community about the priority of measures to improve energy efficiency: some experts prefer improving the thermal insulation of buildings, others — the introduction of intelligent control systems, and others — the integration of renewable energy sources. The present study demonstrates that the greatest effect is achieved with a systematic approach combining various initiatives. The conclusion is formulated that in the current conditions and the future, a comprehensive application of modern thermal insulation materials, highly efficient heating equipment, intelligent management mechanisms, and alternative energy sources is required. The article is of interest to engineers-designers of heating systems, energy managers of commercial facilities, specialists in energy efficiency of buildings, and heads of companies interested in optimizing operating costs and improving the environmental friendliness of their real estate.

Change in the Properties of Expanded Polystyrene Exposed to Solar Radiation in Real Aging Conditions

Although polystyrene materials with added graphite are actively used for the thermal insulation of buildings, there are serious problems with the detachment and warping of these materials under the influence of solar radiation. However, no systematic studies have yet been carried out on the aging of polystyrene under exposure to solar radiation. The article presents research aimed at determining changes in the thermal conductivity, compressive stress, tensile strength, and water absorption of expanded polystyrene with the addition of graphite, exposed to direct solar radiation under in situ conditions. For this purpose, expanded polystyrene (EPS) with the addition of graphite (gray EPS) and expanded polystyrene made of composite panels (gray EPS and white EPS) were exposed to direct solar radiation under in situ conditions. A third sample (reference), which was entirely white polystyrene (without the addition of graphite), was included in the tests. The results showed that expanded polystyrene with the addition of graphite degraded under the influence of direct solar radiation but improved its strength properties. Expanded polystyrene made of composite improved its compressive strength properties by nearly 11 kPa (18%), and expanded polystyrene with the addition of graphite improved its compressive strength properties by 0.4 kPa (0.5%). And the tensile strength for composite-made expanded polystyrene increased by 7 kPa (9%), and that for expanded polystyrene with the addition of graphite increased by 26 kPa (37%). At the same time, water absorption for expanded polystyrene made of composite also increased by 0.06 kg/m2 (60%), and that for expanded polystyrene with the addition of graphite increased by 0.04 kg/m2 (44%).

New robust multi-criteria decision-making framework for thermal insulation of buildings under conflicting stakeholder interests

The choice of thermal insulation technology for existing building retrofit can be a complex multi-criteria decision-making (MCDM) problem characterized by multiple stakeholders with conflicting interests. The conflicting interests of the building owners and the policymakers could negatively influence the adoption of low-carbon energy retrofit measures by building possessors, slowing down the progress toward sustainable development. The investigation of this issue is, therefore, crucial to support more informed decisions and offer policymakers useful insights to develop future economic incentives for energy refurbishment of buildings. Most of the existing MCDM studies on the subject do not emphasize the differences among different stakeholders nor consider the outcomes' robustness. To overcome this gap, this paper integrates multi-stakeholder analyses and robustness assessments to provide broad-spectrum and reliable results. An innovative robust MCDM framework for building thermal insulation under conflicting stakeholder interests is proposed and tested on a real case study building (located in Southern Italy) using building dynamic energy simulation. Several alternatives of thermal insulation are evaluated under environmental, energy, and economic key performance indicators (KPIs). The Analytic Hierarchy Process is used to define criteria weights for conflicting decision-makers representing collectivity (policymakers) and private interests. TOPSIS, VIKOR, WASPAS, and MULTIMOORA methods are integrated to perform initial rankings of the alternatives. A rank similarity analysis is performed to evaluate the consensus between MCDM methods, and an ensemble ranking is obtained for each decision-maker using an approach based on the half-quadratic theory. A Confidence Index and a Trust Level are used to evaluate the agreement among the MCDM approaches, verifying the reliability of the final ensemble ranking. The robustness of the framework is attained by complying with well-established literature guidance. The hybrid MCDM analysis showed that porous materials like expanded clay and expanded perlite lead to better results under the KPIs investigated. The worst performances are attained by vacuum insulation panels and aerogel, mainly due to high values of embodied CO2 emissions and long payback periods. Insights upon the performance of different thermal insulating alternatives are also highlighted by the study and a stakeholder comparative analysis demonstrates that global rankings obtained for the different decision-makers show some similarities, but also important deviations, and a full compromise solution is not achieved.

Pre-treatment and its effect on the thermal conductivity of natural lignocellulosic rice straw stubble waste boards: Analysis vis a vis potential for the civil engineering applications

Once built, the residential or commercial building must maintain a temperature suitable for human comfort. Presently, according to an estimate, building energy consumption contributes about 40 % to global greenhouse gas (GHG) emissions. Thus, it is necessary to develop building materials that not only have low or zero carbon footprints during their production stage but also provide thermal insulation for buildings amidst variable climates. Among such materials, the use of straw waste boards can not only offer an opportunity to reduce the use of GHG-intensive materials but also provide excellent thermal insulation. The objective of the present work is to fabricate, characterize, and evaluate the thermal conductivity of composite boards made from rice (Oryza sativa) straw. The effect of water and alkali pre-treatment is also evaluated. Three different mass fractions (Mf) with 50 %, 60 %, and 70 % of straw by weight are considered, and three different matrix materials, viz., Polyethylene (PE), Polylactic acid (PLA), and epoxy resin, have been used. Among these, the epoxy matrix is found to be most suitable owing to its uniform dispersion, which leads to superior adhesion in the straw laminates. Subsequent morphological characterization techniques, such as energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD), have been employed to evaluate the physicochemical structure changes of straw fibre and fibre boards. The microstructural characterization revealed that the alkali and water pre-treatment have a pronounced effect on the morphological properties of straw and composite boards. Thermal conductivity has been measured using the experimental setup based on the guarded hot plate method, and the lowest conductivity of heat is recorded in the order of 0.023 W/mK. The present research work attempts to demonstrate the development of a novel product using rice straw waste that can potentially replace/reduce the usage of EPS (Expanded Polystyrene) for building construction applications in the near future.

Technology for Protecting Building Envelopes in Construction Using Magnetron Sputtering

The global environmental agenda is aimed at saving energy resources in all areas of human activity. An important condition for energy saving and increasing energy efficiency is the thermal protection of buildings and structures of all types. Currently, when designing and constructing buildings, structurally oriented solutions are needed to provide conditions for the implementation of modern innovative technologies. At the same time, when producing new thermal insulation (heat-protective) materials, it is necessary to take into account such important issues as environmental friendliness and ensuring a comfortable microclimate. Issues of indoor air exchange are extremely important, especially during the spread of new viral infections. Thermal insulation (thermal protection) of buildings must ensure air circulation, that is, be vapor permeable. Polyester material has this property. Modern technologies make it possible to impart heat-reflecting properties to such materials by applying metallized nanolayers or their compounds to their surface. Among the methods for applying such layers, a special place is occupied by the magnetron sputtering method, which is used in the technology of applying protective coatings to the surface of products made from roll and sheet materials. With the development of applied technological research in the chemical industry, many substances (compounds) were invented, some of which gained such popularity that they began to be used in the production of a huge number of materials, including in the construction industry. One of these substances was polyester as a high-molecular compound, which became widely used in many areas of industry. Polyester material is often combined with other man-made or natural fibers. Among them: cotton, linen, wool, polyamide. As a result, we obtain a canvas (materials) with new characteristics, adding new unique properties, such as strength and wear resistance, does not fade in the sun, and does not require special care. Polyester fabric is used for suspended ceilings and in building materials. Its high density of 250 kg per cubic meter allows this to be done. By combining the production of polyester and cotton, the material acquires the properties of breathability, hygroscopicity and low thermal conductivity. The purpose of this article is to describe the technology of the ion-plasma processing method of combined linen materials with possible application in the construction industry.

Life cycle assessment of aerogels: a critical review

Over the past decade, the increasing emphasis on sustainable material production has brought aerogel technology to the forefront of scientific and industrial research. Aerogels are known for their extraordinary properties, such as high porosity and low density, which make them suitable for a wide range of applications from thermal insulation in buildings to drug delivery systems. This review systematically investigates the sustainability of aerogel production by analyzing the environmental impacts identified in recent life cycle assessments (LCAs). It examines studies on aerogel production using different precursors, solvents, and energy-intensive production methods, especially drying techniques, providing a comprehensive analysis of the environmental footprints and highlighting several hotspots. The review particularly focuses on identifying the disparities in LCA methodologies and the results obtained, which are crucial for crafting a roadmap toward more sustainable aerogel production. The findings emphasize the need for standardized functional units and lifecycle phases that reflect the specific applications of aerogels, thus enabling more accurate comparisons and assessments. The review concludes with a discussion of the critical gaps in current LCA studies of aerogels. It also offers sustainability recommendations based on identified hotspots, advocating for improvements in aerogel production techniques that minimize environmental impacts, enhance material efficiency, and reduce waste. By addressing these gaps, this paper aims to foster a deeper understanding of aerogel sustainability and encourage the development of more environmentally friendly practices in aerogel production and application.Graphical

Development of a vibration-damping, sound-insulating, and heat-insulating porous sphere foam system and its application in green buildings

With the development of green buildings, people pay more attention to the quality of the indoor sound environment. The air sound insulation performance of floors and exterior walls plays a key role in today's green buildings. The thermal performance of the enclosure structure's floor and exterior wall heat transfer resistance is an important factor in reducing building carbon emissions in green buildings. The aim of this paper is to study the efficiency of the acoustic and thermal insulation of a foaming system with porous carbon balls and the combination of different structural ways of construction boards and external walls. The acoustic and thermal parameters of different sound insulation and thermal insulation systems designed with porous carbon sphere foam and inserted into the floors and exterior walls are compared to highlight the optimal structure. The theoretical and experimental tests showed that to improve the sound insulation performance of the floor, a sound insulation system needs to be placed on the surface of the floor in contact with the impact object and inlaid in the vertical gap in contact with the floor and the wall. Furthermore, it has been determined that the surface of the foam particle acoustic ball with micropores has good sound absorption performance. Finally, the high-quality building thermal insulation material with low thermal conductivity in any combination with the floor slabs and the external wall structure improves the thermal insulation performance.

Modelling and measurements of heat transfer coefficient in classroom experiments

Thermal insulation of buildings is important because it has both ecological and social impacts. Most often, it is characterized by the so-called U-value. Heat transfer through walls includes conduction, convection, and thermal radiation. This leads to complex measurements and calculations for assessing the effectiveness of different insulating materials, and the usual methods are not suitable for classroom experiments. We propose a simple method for measuring the U-values of varied materials used in everyday life that can be performed in the classroom. It is based on measuring the temperature inside and outside a box, and the power, released by a resistance coil inside the box.

Building a sustainable future: Exploring the nexus between climate awareness and thermal insulation choices in new home construction

Climate change is considered a major threat to the environment and society as a whole. Reducing building energy consumption through the use of thermal insulation is one way of combating climate change. This study examines the impact of climate change awareness on the pre-construction decision of Lebanese homeowners to use thermal insulation in their new homes. A model building consisting of a typical 160 m2 single-family home was used and its thermal loads were calculated in two cases: insulated and uninsulated case, in three different locations in Lebanon: Beirut, Chtaura, and Bcharre-Arz. The thermal loads were calculated using two methods: the degree-days empirical method, and the Hourly Analysis Program software numerical method. The computations showed energy reduction ranging between 23% in the coastal region to 52% in high mountains when thermal insulation of thickness 5 cm was used. The investment payback period ranged from 4.3 years in the coastal region to 1.5 years in the high mountains. A survey addressed to 100 respondents was used to understand how Lebanese homeowners’ decision to use thermal insulation was affected by knowledge of the obtained results. The survey results showed that climate change awareness has a high impact on this decision; however, the cost seems to play an important role in the owners’ final decision on whether or not to use thermal insulation. Spreading awareness about climate change and the payback periods of building thermal insulation will increase its use since the number of respondents refusing to use thermal insulation drastically decreased after being informed about its payback period.

Experimental study on chemical and thermomechanical properties of concrete incorporating Washingtonia robusta fibres

The aim of this work is to provide a new composite material for applications in the thermal insulation of buildings. The composite was made with mortar reinforced with natural fibres extracted from the petiole of the Washington robusta (WR) palm tree. The fibres used were first chemically characterised by energy-dispersive X-ray spectroscopy, scanning electron microscopy, X-ray and infrared diffractometry spectroscopies alongside tensile testing to discover their morphological structure. Afterwards, the fibres were incorporated into mortar with mass percentages varying from 0 to 4% to determine experimentally the thermomechanical properties of the manufactured samples. The chemical findings indicated that WR fibres are rich in cellulose, hemicellulose and lignin, and possess a high crystallinity index, which enhances the mechanical properties and durability of the composite. The density obtained for the composite W2RC4% is 1305 kg/m3 and less than 2000 kg/m3; this composite can thus be classified as a lightweight concrete according to the standard NF EN 206 + A2/CN (2022). The thermal conductivity and thermal effusivity dropped by about 60% and 42%, respectively. Moreover, the WR reduces the compressive strength (76%) and the flexural strength (36%) to minimum values, respectively, of 5.9 MPa and 3.8 MPa. These values meet the mechanical requirements of lightweight concretes (&gt; 3.5 MPa).

Analysis of the Cooperation of a Compressor Heat Pump with a PV System

The decarbonization of heating systems is one of the present political and legislative directions of the European Union and its Member States. The main activities concern the energy performance of buildings and energy efficiency. The mentioned UE directives are the basis for the financial support of high-emission fossil fuel thermal energy source replacement with emission-free ones, in particular heat pumps. Other aspects are the support of PV installations and the thermal insulation of buildings. 85% of EU buildings were built before 2000, and among those, 75% have poor energy performance. Therefore, a significant number of buildings have only high-temperature wall radiators, and this was a motivation to prepare this article. The main innovation of this research was a new theoretical design of a high-temperature heat pump based on ecological refrigerants. The presented solution allows wall radiators to receive a hot water supply with temperatures of up to 85 °C during external temperatures of up to −20 °C. Typical heat pumps do not have these kinds of parameters, so the authors decided to verify the possibility of operating this device in such a wide temperature range. Another important aspect was the analysis of PV support. Finally, this paper investigates the possibility of heating an energy-efficient house with the newly designed high-temperature heat pump. Depending on the location in Poland, i.e., Suwałki, Warsaw, and Wrocław, the total electric energy supplied to the compressors was 2538–3364 kWh. The energy provided by the PV to supply power to the compressors is 482–570 kWh. The achieved PV energy self-consumption is 16.9–19.0%. The Seasonal Coefficient of Performance (SCOP) of the heat pump is 1.825–2.038 without PV and 2.515–2.970 with PV.

Physico-mechanical, thermal insulation properties, and microstructure of geopolymer foam concrete containing sawdust ash and egg shell

Recently, energy conservation through building thermal insulation has gained significant importance in solving sustainability-related issues. In this context, this study investigates the potential for manufacturing geopolymer foam concrete (GFC) containing eggshell powder (ESP) and sawdust ash (SDA) using aluminium (Al) powder as a foaming agent. The role of Al-powder percentages on the mechanical and thermal properties of GFC was thoroughly investigated. The effect of ESP and SDA incorporation as partial replacements of precursors (from 0 to 20 %) on the thermal properties, durability, and microstructure of GFCs were also discussed. The experimental findings demonstrate that the bulk density and compressive strength of GFC with different Al-powder contents ranged between 1928 and 1798 kg/m3 and 17.45 and 9.37 MPa, respectively. The SEM images and MIP tests show that foams with different numbers of micro- and macropores are formed in GFCs. The ESP-based GFC had an apparent porosity range of 13.09 %–10.29 % and a bulk density range of 1823 to 1713 kg/m3. The SDA-based GFC had an apparent porosity range of 14.21 %–12.96 % and a bulk density range of 1834 to 1807.8 kg/m3. It was found that the 10 % ESP and 5 %, SDA mixtures enhanced the strength by 16.54 % and 4.45 %, respectively, compared to the control mix. The thermal conductivity, thermal diffusivity, and specific heat of 10 % ESP-mixture and 5 % SDA-mixture were 1.237 and 1.167 W/(mK), 0.795 and 0.922 mm2/S, and 1.556 and 1.266 MJ/m3K, respectively. Finally, the residual strength and microstructure investigations demonstrate that ESP-based GFCs have more stability than SDA-based GFCs and the control mix when subjected to elevated temperatures.

Moisture absorption and desorption characteristics and prediction model analysis of building thermal insulation materials

Understanding the isothermal moisture absorption and desorption characteristics of building thermal insulation materials and how they affect thermal conductivity, is curial for accurate building thermal design and energy-saving calculation. In this paper, five types of building thermal insulation materials are selected for investigation. First, the variation trend of the equilibrium mass moisture content of materials in different moisture absorption and desorption stages is studied employing the saturated salt solution method and the constant temperature and humidity box method, and the effect of temperature on the moisture absorption and desorption processes is evaluated. Additionally, the applicable model of the material in the moisture absorption and desorption process is obtained through a fitting analysis of the experimental data. Finally, the influence of the material’s moisture absorption and desorption characteristics on the thermal conductivity is analyzed using the transient thermal conductivity test method. The results highlight that there is a need to consider the moisture absorption and desorption processes to accurately determine the wet material thermal conductivity, and the hysteresis effect of the material in the moisture absorption and desorption processes is directly related to its microstructure and the relative humidity at the initial moisture desorption. At a temperature of 25 oC, the autoclaved aerated concrete exhibits its highest hysteresis rate of thermal conductivity during the moisture desorption process of third stage, reaching 13.2%.

Fabrication of Porous Anorthite Ceramic Insulation Using Solid Wastes.

Porous anorthite (CaAl2Si2O8) ceramics, suitable for thermal insulation in buildings, were obtained using waste seashells as a source of CaO, kaolin as a source of Al2O3 and SiO2 and banana peel as a pore former. Changing the volume of banana peel as well as the processing temperature was found to be an effective approach to control the thermo-mechanical properties of the obtained anorthite ceramics. The sintering of powder compacts containing up to 30 wt% banana peel at temperatures ranging from 1100 to 1200 °C resulted in anorthite ceramics possessing up to 45% open porosity, a compressive strength between 13 and 92 MPa, a bulk density between 1.87 and 2.62 g/cm3 and thermal conductivity between 0.097 and 3.5 W/mK. It was shown that waste materials such as seashells and banana peel can be used to obtain cost-effective thermal insulation in buildings.

Pore structure characterization and effective thermal conductivity modeling of fibrous building thermal insulation materials based on X-ray tomography

The existing structural characterization methods of building materials as well as thermal conductivity calculation models can not be directly applied when considering fibrous building thermal insulation materials with intricate skeletons. In this study, rock wool is considered the research object, and the X-ray tomography method is used to characterize the pore structure and extract structural parameters. Based on the actual pore morphology of the material, the pores in the representative elementary volume (REV) are reasonably assumed to be cubic. Additionally, considering the contact thermal resistance of fibers and the randomness of pore distribution, the curved pattern of heat conduction pathway with the ever-changing diameter is reasonably simplified into a series-parallel form of the curved heat chain with the same diameter. On this basis, the fractal models of effective thermal conductivity are established in horizontal and vertical directions. Finally, a modified formula for the effective thermal conductivity calculation of fiber thermal insulation materials is proposed, taking into account the influence of fiber orientation on the material thermal conductivity. It was shown that the relative deviation between the calculated correction value and the experimental value of the effective thermal conductivity is all less than 16.13%.