Insulation Requirements Research Articles

Comparative Analysis on the Characteristics of Liquid Lead and Lead–Bismuth Eutectic as Coolants for Fast Reactors

With the increasing global demand for sustainable energy, the importance of advanced nuclear technologies, such as fourth-generation reactors, has become increasingly prominent. Fourth-generation reactors often use non-water coolants, among which liquid lead and lead–bismuth eutectics (LBEs) are highly promising, making lead-cooled fast reactors (LFRs) a popular area of research internationally. On the basis of extensive analysis and comparison conducted previously, this article summarizes and analyzes the advantages, problems, and differences in lead and LBE as LFR coolants. Overall, both lead and LBE have excellent neutronic characteristics, good heat transfer performance, and chemical inertness, and make LFRs highly efficient in nuclear fuel utilization, inherently safe, and relatively simplified in design. However, both of them corrode materials severely and produce highly toxic 210Po, which are the problems that need to be considered for further engineering development. Moreover, LBE has a lower melting point, which allows a wider temperature range and lower insulation requirements in its design, making it easier to achieve engineering and miniaturization under the same conditions. Lead has a lower cost, is less corrosive to materials, and produces less 210Po, which makes it a more ideal coolant for future development.

Decoding Carbon Footprints: How U.S. Climate Zones Shape Building Emissions

The construction industry accounts for over 40% of carbon emissions in the United States, with embodied carbon—emissions associated with building materials and construction processes—remaining underexplored, particularly regarding the impact of location and climate. This study addresses this gap by investigating the influence of different climate zones on the embodied carbon emissions of residential buildings. Using Building Information Modeling (BIM), 3D models were developed based on the 2021 International Energy Conservation Code (IECC) and International Residential Code (IRC). A lifecycle assessment (LCA) was conducted using Environmental Product Declarations (EPDs) to evaluate the embodied carbon of building materials during the product stage. The findings reveal that buildings in colder climates exhibit higher embodied carbon emissions, ranging from 25,768 kgCO2e in Zone 1 to 40,129 kgCO2e in Zone 8, due to increased insulation requirements. Exterior walls and roofs were identified as significant contributors, comprising up to 34% of total emissions. Sensitivity analysis further indicates that the window-to-wall ratio and interior wall design substantially affect embodied carbon, with baseline emissions around 170 kgCO2e/m2 in warm areas and 255 kgCO2e/m2 in cold areas. These results establish a baseline for lifecycle embodied carbon values across different climate zones in the United States and align with international standards. This study provides valuable insights for policymakers and designers, offering data to inform effective carbon reduction strategies and optimize building designs for sustainability.

Design and thermal performance analysis of self-insulation concrete compound blocks

More than 60% of energy losses occur through the building envelope. Exterior wall insulation technology is widely used for wall insulation, but it is prone to cracking, falling off, and causing fires. Self-insulation concrete compound blocks (SIB) have attracted considerable attention in recent years for meeting building energy efficiency standards without the need for external insulation treatment. In this study, the shale ceramsite concrete (SCC) was prepared as the base material for the blocks through the orthogonal test and range analysis. In accordance with the insulation requirements of residential building walls, 12 types of self-insulation concrete compound blocks (SIB) were designed. The heat transfer process of these blocks was simulated and analyzed using Ansys Workbench, enabling a comparison of the thermal conductivity effects resulting from different hole distribution schemes in the insulation blocks. The simulated values were compared with the theoretical calculations, and the simulated results were in good agreement with the theoretical calculations. The results showed that TZ-12 exhibited the optimal hole configuration with a heat transfer coefficient of 0.5 W/(m2·K), which was 38.3% lower than that of the external insulation block TZ-9. Additionally, TZ-12 demonstrated the average compressive strength of 8.28 MPa and the minimum compressive strength of 7.45 MPa, meeting the requirements for MU7.5 strength grade and also satisfying the requirement of not less than MU5.0 when self-insulation blocks were used for external walls. The simulated heat flux rate of the self-insulation concrete compound block wall (SIBW) was 15.4 W, and its heat transfer coefficient was 0.56 W/(m2·K), which was 29.1% lower than that of the external thermal insulation wall (ETIW), meeting the design standard for achieving the 65% energy saving in residential buildings situated in regions with hot summers and cold winters.

Effect of Triple Glass Layers on the Thermal Performance of Windows

This study introduces the application of software simulations to evaluate the performance of triple-pane glass windows to meet the requirements for energy-efficient thermal insulation. Using Therm 7.8.55 and Window 7.8.55 software, structural and physical heat transfer models for various single-frame plastic windows were developed. Numerical simulation methods were employed to calculate and analyse the impact of the number of glass layers on the windows' thermal performance, including the heat transfer coefficient and solar heat gain coefficient, to elucidate the energy-saving mechanisms. These simulations examined the physical properties of single-frame triple-glazed plastic windows, such as wind pressure resistance, airtightness, watertightness, and potential condensation on the inner surface. The results indicate that, under identical conditions, the heat transfer coefficient of single-frame triple-glazed plastic windows is reduced by 7.08%, and the solar heat gain coefficient is decreased by 4.18% compared to single-frame double-glazed plastic windows. Additionally, these windows' physical and economic performance meets the necessary standards. Furthermore, incorporating new materials such as Low-E glass can further enhance the thermal performance of the windows, significantly contributing to the reduction of overall building energy consumption.

Thermal and mechanical analysis of thermal break structure in balcony with basalt fiber reinforced polymer

Thermal break structure is an effective design to reduce building energy consumption in balcony. The traditional stainless-steel bars or other FRP components reinforced thermal break structures can't enable both mechanical performance and thermal insulation concurrently because these materials are difficult to have low thermal conductivity and high mechanical properties at the same time. This paper proposes to use basalt fiber reinforced polymer (BFRP) to construct the thermal break structure due to the high load-bearing capacity and thermal insultation of BFRP. The thermal performance of the structure is systematically verified through three-dimensional simulation. Influence of thermal break widths, loading point positions, shear reinforcement forms and reinforcement types on the mechanical properties of the structure is investigated. The results show that BFRP can significantly reduce the linear heat transfer transmittance while ensuring structural mechanical properties. A larger thermal break width leads to the low load-bearing capacity of the structure. Lower BFRP compressive reinforcements need enough diameter to provide compressive strength and shear reinforcement forms can significantly increase the mechanical properties of the thermal break. Upper tensile reinforcements can be selected depending on the stiffness and insulation requirements in practical engineering. Based on experimental results, force transfer mechanism is analyzed and the rationality of the structural design is identified. The maximum length of the cantilever slab without shear reinforcement forms is approximately 2.94 m when meets the serviceability limit state. The results suggest that newly designed BFRP thermal break structure can effectively solve thermal bridge problems in balcony.

Honeycomb Molding - Forming Thermoplastic Sandwich Structures for Interior Applications

Trains play an important role in the sustainable mobility of the future. The changes in the market are reflected in the number of newly approved series by the German Federal Railway Authority (EBA); 226 new designs and redesigns of train cars were approved for use on German rails in 2019. Phenol-formaldehyde resins are used extensively specifically for railcar interiors. However, phenol-formaldehyde resins release carcinogenic vapors during and even after production if not completely sealed. As a result, European production standards and requirements have been increased, making the material less economical and increasingly difficult to enter the market. Further bans aimed at lower formaldehyde release limits are currently being considered by the European Union's Committee for Risk Assessment (RAC) and Committee for Socioeconomic Analysis (SEAC). In order to develop and design alternative materials, it is important to meet the requirements for stiffness, light weight, insulation and sustainability simultaneously. This research aim is therefore to develop a new class of material for interior components with improved stiffness, lower weight, lower CO2 footprint and no health hazards. The approach is to develop advanced composite sandwich panels that retain the ability to be molded into complex structures for interior applications. This is done through a thermoplastic honeycomb core structure that is manufactured directly from sheet material and fiber reinforced organo-sheets as the outer layers. The base matrix for all layers is kept uniform for better recyclability and consists of polycarbonate (PC) with sufficient flame retardant properties to provide an environmentally friendly alternative to existing phenolic resin and aramid epoxy honeycomb solutions while still complying with the security norms.

Research on assessing and enhancing indoor thermal and air conditions within typical elementary school classrooms in southern China

The thermal design of buildings in hot summer and cold winter regions must meet the requirements of thermal insulation in summer and heat preservation in winter. As a vital component of national compulsory education, primary schools must create a good indoor thermal environment for classrooms, which is particularly important for students. Due to the lack of construction standards and limited research on Chinese regions with hot summers and cold winters, policymakers have no comprehensive and efficient approach to creating optimal indoor thermal conditions in primary school classrooms. Therefore, based on the climate conditions of hot summer and cold winter areas, this study conducted field surveys in primary and secondary schools in hot summer and cold winter areas, summarized and analyzed the current situation of the surveyed classrooms and users' subjective evaluation of the indoor thermal environment of classrooms, and summarized the current hot summer and cold winter conditions. Problems in classrooms in primary and secondary schools in the region are clarified, and the research direction of construction strategies is clarified. The study found that most of the school hours in summer and winter were in a poor indoor thermal environment without refrigeration equipment. This study adjusted the school leaving time to 17:20 in summer and 17:00 in winter by adjusting the school leaving time to reduce the time of adverse thermal environment.

Application of Experimental Studies of Humidity and Temperature in the Time Domain to Determine the Physical Characteristics of a Perlite Concrete Partition

These days, the use of natural materials is required for sustainable and consequently plus-, zero- and low-energy construction. One of the main objectives of this research was to demonstrate that pelite concrete block masonry can be a structural and thermal insulation material. In order to determine the actual thermal insulation parameters of the building partition, in situ experimental research was carried out in real conditions, taking into account the temperature distribution at different heights of the partition. Empirical measurements were made at five designated heights of the partition with temperature and humidity parameters varying over time. The described experiment was intended to verify the technical parameters of perlite concrete in terms of its thermal insulation properties as a construction material used for vertical partitions. It was shown on the basis of the results obtained that the masonry made of perlite concrete blocks with dimensions of 24 × 24.5 × 37.5 cm laid on the mounting foam can be treated as a building element that meets both the structural and thermal insulation requirements of vertical single-layer partitions. However, it is important for the material to work in a dry environment, since, as shown, a wet perlite block has twice the thermal conductivity coefficient. The results of the measurements were confirmed, for they were known from the physics of buildings, the general principles of the formation of heat and the moisture flow in the analysed masonry of a perlite block. Illustrating this regularity is shown from the course of temperature and moisture in the walls. The proposed new building material is an alternative to walls with a layer of thermal insulation made of materials such as polystyrene or wool and fits into the concept of sustainable construction, acting against climate change, reducing building operating costs, improving living and working conditions as well as fulfilling international obligations regarding environmental goals.

Superhydrophobic foamed concrete based on response surface method: Mix design and its potential application in roofing systems

This study employs the response surface method to optimize the mixture design of superhydrophobic foamed concrete. The study investigates the influence of calcium stearate (CS, dosage 1 %∼5 %), polydimethylsiloxane (PDMS, dosage 2 %∼8 %), and hydroxypropyl methylcellulose (HPMC, dosage 0.05 %∼0.2 %) on various properties of foamed concrete, including density, compressive strength, contact angle, and water absorption. Additionally, the research explores the application of superhydrophobic foamed concrete in integrated roofing systems and assesses its thermal and structural performance through finite element analysis. Results reveal that foamed concrete achieves a contact angle greater than 150° when formulated with a mix ratio of CS (3 %), PDMS (8 %), and HPMC (0.05 %), or CS (3 %), PDMS (5 %), and HPMC (0.125 %). A negative linear correlation between the heat transfer coefficient and the thickness of foamed concrete is found. Furthermore, the heat transfer coefficient is inversely related to the spacing between the concave and convex drainage boards. Specifically, for a toe spacing of 50 mm and foamed concrete thickness exceeding 70 mm, the heat transfer coefficient of the roof measures 0.788 W/(m²·K). When the roof thickness increases from 70 mm to 100 mm, the roof heat transfer coefficient drops to 0.69 W/(m2∙K). When the toe spacing is increased from 50 mm to 60 mm, the heat transfer coefficient of the roof drops sharply to about 0.66 W/(m2∙K) at the thickness of 50 mm. The insulation requirements for the roof are satisfactorily met to 0.8 W/(m²·K). Under applied roof loads, the maximum von Mises stress experienced by the integrated roof is 0.6 MPa at a toe spacing of 50 mm. With the increase of the roof thickness, the maximum value of the DAMAGEC damage coefficient gradually decreases from 0.3 to 0.17. The maximum damage position has always been at the weak position of the four corners, which is consistent with the actual use status. The research findings on superhydrophobic foamed concrete have significant theoretical and engineering application value. Moreover, the construction of an "insulation/hydrophobic integrated" roof system demonstrates the feasibility of an integrated roof system and the potential for insulation/hydrophobic integration in roof system construction.

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.

Ventilation and windows in The Netherlands

The Dutch Building decree gives rules for the ventilation and sound insulation of facades. In the standards a lot of possibilities are described to fulfil these requirements. In this paper the most frequently used methods are described. It also became clear that in the course of the last 40 years some methods for natural ventilation are not in use any more for newbuilt dwellings because of problems with insect-nuisance and housebreaking. Therefore special ventilation grids and muffles are in use to fulfil the requirements both for ventilation and sound insulation of facades. In that case open windows play no role in case of ventilation but only when people want to get fresh air in a short time by opening windows on both sides of the dwelling. In that case there are no requirements for sound insulation of facades. In this paper the fulfilling of the sound insulation of facades and ventilation are described .

Resonant frequencies of multi-layer building constructions: Estimation by measurement of acceleration amplitudes

The Austrian building regulation requirements for impact sound insulation are based on the weighted standardized impact sound pressure level as single-number specification. In recent years, it has become apparent that not only the single-number specification, but the extended frequency range and frequency characteristics of impact sound insulation of constructions can have noticeable influence on the perceived acoustic performance of a construction. Therefore, the Austrian Classification Standard ÖNORM B 8115-5: 2021-04 includes extended requirements on impact sound insulation. It provides two ways for verification of the sound insulation classes A to C. One way is the verification via the resonance frequency of multi-layer constructions. However, there exist as yet no standardized measurement methods for the estimation of the resonance frequency of multi-layer building constructions. In response, in course of this study a new measurement method for the estimation of the resonance frequencies of multi-layer constructions was developed. For this development acceleration measurements were carried out on both surfaces of particularly double-layer building constructions, that were excited with a rubber hammer. From these measurement results, in conjunction with an analytical model, it was possible to derive a measurement method for estimating the resonant frequency via the frequency characteristics of the acceleration amplitudes.

Extending the frequency range of ISO 717-2 - a look at options and issues

In 2019, the Norwegian Standard NS 8175, which defines requirements for sound insulation in Norwegian buildings, was revised to include low frequency spectrum adaption terms for new dwellings. This change affects the applicability of measurements of weighted improvement of impact sound insulation, delta Lw, as the spectrum for calculating delta Lw, given in ISO 717-2, is limited downwards to 100 Hz. For a floating floor construction, this means that floors with a resonance frequency well below 100 Hz, and correspondingly a relatively high delta Lw, will be overrated in the sense that the measured delta Lw will be unaffected by the poor low frequency performance of the floating floor. To properly address this increased focus on low frequencies, an extended range spectrum is needed. In the work leading to this paper, a selection of extended range values for the reference heavyweight floor have been suggested, starting with a linear extrapolation of the values given in ISO 717-2. Data from laboratory measurements of delta Lw for floating floors have then been used to investigate the suitability of the suggested values. The results are summarised and discussed in this paper.

ETICS measurements and prediction - Verification and validation of a predictive model for the improvement of airborne sound insulation of thick external linings

The increasing demand of the reduction of carbon emissions and the consumption of energy resources due to the construction sector leads to the concept of Zero-Energy buildings. It is therefore crucial ensuring technical and engineering compatibility between future advancements in energy efficiency and sound insulation. The sound insulation requirements for residential buildings are mandatory in Italian Regulations, tested on-site after construction completion. A noteworthy challenge is the potential synergy between specifications for energy efficiency and the sound insulation properties in building materials. This paper deals with the validation of the prediction model for the improvement of airborne sound insulation due to thick external linings, particularly materials used in ETICS (External Thermal Insulation System), based on mechanical properties of involved materials. Standard ISO 9052-1 for the determination of dynamic stiffness is intended for materials used under floating floors in dwellings. However, based on the methods of this standard, it is possible to perform measurements (with both hammer and shaker) even on thick linings materials, and use the results for the implementation of computational models for the predictions of airborne sound insulation improvement, as a function of frequency, with good accuracy.

Are single number ratings for sound insulation requirements still up-to-date?

In general, soundproofing requirements are given in form of a single number rating. Individual values are therefore singular, i.e. precise, so that no uncertainties are taken into account when checking the quality by measurement or calculation. A better description of the quality of sound insulation would be the formation of classes. In Europe requirements are mainly expressed as a weighted apparent sound reduction index R'w, or by specifying a certain weighted standard sound level difference DnT,w. Both quantities describe a quality that is not necessarily equivalent. The numerical comparison of the requirements is therefore not or only approximately possible. In light of this consideration requirements should be given therefore by classes. In this paper, the difference between a single number rating and a class rating is discussed.

Research on insulation design of 10 kV medium-voltage cascaded energy storage system

Abstract The insulation design of a medium-voltage cascaded energy storage system is very important due to its direct access to the AC medium-voltage network. This paper focuses on improving the reliability and safety of the system operation, and realizes the insulation design of a 10 kV medium-voltage cascaded energy storage system through the selection of insulation materials and structural innovation. In the structure, high insulation sheet molding plastic was used to suspend the battery. The ultra-low conductivity coolant was used to enhance the insulation performance between battery modules. The stability and practicability of the insulation structure are demonstrated by effective test methods. The research shows that the medium voltage insulation design meets the insulation requirements of the 10 kV voltage class, and has high industrial practical value for the project of medium voltage cascaded energy storage system.

Thermodynamic modelling of low fill levels in cryogenic storage tanks for application to liquid hydrogen maritime transport

One of the key challenges in transporting liquid hydrogen (LH2) in bulk onboard carriers is the requirement for high performance insulation to reduce the heat transfer and cargo boil-off losses. After unloading their cargo, carriers on the return voyage may retain a small amount of liquid (heel) to keep tanks relatively cold, as well as to chill down to the tanks prior to cargo loading. Therefore, there is an aim to reduce net heat transfer into the tank while minimising the required volume of heel. While practices are relatively mature in the liquefied natural gas (LNG) industry, it is not clear how this may differ for future LH2 carriage. In this study, a new analytical, lumped-mass model was proposed to predict vapour stratification and tank warm-up. A 40,000 m3 double-walled LH2 spherical tank was considered with vacuum perlite and polyurethane foam (PUF) insulation, and the effects of tank pressurisation and fill level on cumulative heat gain were investigated. The model pointed to key differences between the two insulation types. Heat gain in the vacuum perlite tank was not predicted to be sensitive to changes in fill level, while heat gain in PUF tank was predicted to be less sensitive to pressurisation. In each case, pressurisation was predicted to enable reductions in heel boil-off which offset any associated increase in cumulative heat gain. In comparing LNG and LH2, the model pointed to a slower thermal response of the LH2 tanks. Consequently, the increase in inner shell temperature was not expected to lead to significant reductions in environmental heat transfer into the tank. The findings of this study point to potential operational differences in the management of LNG and LH2 heel during the ballast voyage as well as considerations for vacuum insulated tanks.

Thermal Energy Storage in Concrete by Encapsulation of a Nano-Additivated Phase Change Material in Lightweight Aggregates.

This work discusses the applicability of lightweight aggregate-encapsulated n-octadecane with 1.0 wt.% of Cu nanoparticles, for enhanced thermal comfort in buildings by providing thermal energy storage functionality to no-fines concrete. A straightforward two-step procedure (impregnation and occlusion) for the encapsulation of the nano-additivated phase change material in lightweight aggregates is presented. Encapsulation efficiencies of 30-40% are achieved. Phase change behavior is consistent across cycles. Cu nanoparticles provide nucleation points for phase change and increase the rate of progression of phase change fronts due to the enhancement in the effective thermal conductivity of n-octadecane. The effective thermal conductivity of the composites remains like that of regular lightweight aggregates and can still fulfil thermal insulation requirements. The thermal response of no-fines concrete blocks prepared with these new aggregates is also studied. Under artificial sunlight, with a standard 1000 W·m-2 irradiance and AM1.5G filter, concrete samples with the epoxy-coated aggregate-encapsulated n-octadecane-based dispersion of Cu nanoparticles (with a phase change material content below 8% of the total concrete mass) can effectively maintain a significant 5 °C difference between irradiated and non-irradiated sides of the block for ca. 30 min.

Experimental and numerical study on the shear performance of stainless steel-GFRP connectors for use in precast concrete sandwich panels

Precast Concrete Sandwich Panel (PCSP) is composed of concrete load-bearing panels, thermal insulation panels, and decorative panels, which are assembled through connectors, integrating load-bearing, thermal insulation, and decorative functions. The connector bears the main shear force between the wall panels, and the shear resistance and insulation performance of the connector largely determine the mechanical stability and insulation effect of the wall panels, which is a key component in PCSPs. The current common practice is to cross assemble stainless steel insulation (SSI) connectors and Glass-Fiber-Reinforced Plastic (GFRP) connectors into PCSPs, which can reduce building energy consumption and save resources while meeting strength and insulation requirements. A large-scale pull-out test on a PCSP with intersecting SSI-GFRP connectors was conducted in this paper. The damage process and damage pattern of PCSP were observed and the shear performance of SSI-GFRP connectors was analyzed. Secondly, a numerical analysis model of the test PCSP was built using ABAQUS finite element software and its validity was verified through the test data. In addition, parameters such as connector diameter, connector number ratio and concrete strength were analyzed for their effect on the shear performance of SSI-GFRP connectors and it was found that connector diameter and connector number ratio had a significant effect. Finally, it is found that there are some differences between the classical theory for calculating the shear performance of SSI-GFRP connectors and the actual results. A theoretical correction factor (ζ) is given to improve the accuracy of the calculation of the classical theory, and its influencing factors and changing rules are investigated.

Double-panel metamaterial with multi-resonator for broadband sound insulation

Currently, double-layer panels are usually filled with damping and sound-absorbing materials, which can effectively reduce the intensity of sound waves and enhance the sound insulation capability in the mid to low frequency range. Although this method can improve the peak and valley values in sound insulation to a certain extent, it still struggles to meet stricter design standards and requirements. This paper proposes a double-layer metamaterial plate with multi-resonator (DLMPMR) to fulfill sound insulation requirements through modifications to the double-layer plate structure. Firstly, the mathematical model pertaining to the sound insulation of DLMPMR is derived utilizing on the transfer matrix method and subsequently verified by the finite element analysis approach. Secondly, the influence mechanism of diverse structural parameters on the sound insulation performance of DLMPMR is studied. It is explored that the sound transmission loss (STL) of DLMPMR can be improved by adjusting the structural parameters to enhance the resonance of the structure across a broader frequency range and shifting the resonance frequencies to lower ranges. Finally, the sound insulation capability of the structure is verified through the reverberant fully anechoic chamber. The results demonstrate that the structure exhibits acoustic performance surpassing the mass law in the range of 220-5000 Hz. The proposed metamaterial, owing to the light weight and thinness, demonstrates promising potential for various applications in noise control engineering.