Insulation Techniques Research Articles

Valve design considerations in liquid hydrogen systems to prevent failure

Hydrogen has potential as an alternative source of energy (energy carrier) because it can be converted, stored, and used efficiently, with a wide range of applications. It can be created from renewable energy sources and can thus serve as storage of renewable energy like wind- and sun-power. It shall be noted that Hydrogen liquefies at -252.9 °C, so cryogenic systems and sophisticated insulation techniques are necessary. Control of the flow has always been carried out by valve assemblies in processing plants. The proper design of industrial valves in every industry, including hydrogen systems, can significantly improve the safety and reliability of the valves specifically, as well as the plant as a whole. An overview of various previous studies is presented in this paper, discussing important design concepts for cryogenic valves. The main research question is to determine what are the main design considerations for valves used in liquid hydrogen systems, to minimize the risk of leakage from the valves to ensure required safety. In this study, different aspects of valve design for liquid hydrogen are examined, such as selection of steel materials, steel wall thickness calculations, stem design, sealing material selection, fire-safe design, cavity over-pressure protection, and body and bonnet extension.

Mathematical Modeling of Wax Deposition in Field-Scale Crude Oil Pipeline Systems

The formation of solid wax crystals, which interlock and form a gel-like layer on the inner wall of the crude oil pipeline, influences the transportation of waxy crude oil. The deposited layer grows continuously and hardens during the oil transportation, reducing the effective inside diameter of the crude oil pipeline and the flow rate. In extreme cases, the deposited layer may block the crude oil pipeline leading to a loss of production and capital investment. In this paper, wax deposition from multiphase flow in field-scale oil pipeline transport systems has been studied. The novelty of this work is to develop a mathematical model that incorporates water-in-oil emulsions, wax precipitation kinetics, molecular diffusion, and shear dispersion to enable accurate predictions of both the wax deposit growth rate and aging of the deposit. The coupled nonlinear partial differential equations governing the flow are discretized in time by a second-order semi-implicit time discretization scheme based on the Adams-Bashforth and Crank-Nicolson methods, which completely decouples the computation of the governing equations. The resulting temporal schemes are discretized in space by the bivariate spectral collocation method based on Chebyshev-Gauss-Lobatto grid points and simulated in MATLAB software to obtain the profiles of the flow variables. The simulation results are presented in graphical and in tabular forms and discussed. This study found that the deposit thickness is directly proportional to the Reynolds number and inversely proportional to the mass Grashof number, Schmidt number, and Weber number. Deposit aging is rampant during the early stages of wax deposition, after which it stabilizes at a specific value as time elapses. A deposition model to predict the wax deposit thickness and aging is proposed in this study. The findings of this study will help in making informed decisions on the planning of pigging operations, thermal insulation, and other remediation techniques to be applied in controlling wax deposition in field-scale crude oil pipeline systems.

The Effectiveness of a Simulation Model of Thermal Insulation in Building Materials Using Cellulose Extracted from Agricultural Waste in Baghdad

This study found that one of the constructive, necessary, beneficial, most effective, and cost-effective ways to meet the great challenge of rising energy prices is to develop and improve energy quality and efficiency. The process of improving the quality of energy and its means has been carried out in many buildings and around the world. It was found that the thermal insulation process in buildings and educational facilities has become the primary tool for improving energy efficiency, enabling us to improve and develop the internal thermal environment quality processes recommended for users (student - teacher). An excellent and essential empirical study has been conducted to calculate the fundamental values ​​of thermal conductivity coefficient for different types of cement mortar, including the different concentrations of cellulosic fibers. And in our study, those cellulosic fibers obtained from sugarcane and sugarcane residues (agricultural waste materials) were used. The percentage is 10%; 20% and 30% of cellulose fibers were added to the cement mixtures. Then the differences are measured, specifically in the physical properties (heat capacity, density, and thermal conductivity coefficient) for 28 days. The Design-Builder program also implemented a precise simulation of the thermal loads of the external envelope of the educational building that is exposed to direct sunlight before and after the insulation process. It was found that with the use of thermal insulation material (meaning the cellulosic fiber technology) mixed with the cement mortar layer of the educational building, the given value of the heat transfer coefficient W/m2 Kelvin decreased by 47.2%. Accordingly, this contributed significantly to a significant and very significant saving in the values ​​of electrical energy consumption by 11.9% for cooling and heating operations and to reducing dangerous carbon dioxide emissions by 52.2%. The simulation has shown that applying thermal insulation techniques to all buildings and educational facilities is highly recommended to save a large consumption in the value of electrical energy and the costs of waste materials and to ensure integrated protection for the ecosystem.

Air Cavity Building Walls: A Discussion on the Opportunity of Filling Insulation to Support Energy Performance Improvement Strategies

The paper intends to discuss the use of cavity wall insulation in existing buildings for energy improvement. Cavity walls are widely spread throughout the EU, typically in buildings from the 20th century, which are recognized as the subject of urgent and deep energy renovation interventions. Their main characteristic is an empty air cavity between two layers of building materials (typically brick, stone, or concrete). Filling the empty air cavity with insulating materials reduces energy loss by transmission through opaque envelope surfaces, and therefore, it represents a cheap solution to obtain a significant reduction in building energy consumption. Various aspects should be carefully evaluated for the effectiveness of this type of intervention: The first step is knowing the materials’ behavior depending on their thermal and hygrometric parameters (conductivity and transmittance, thermal bridge transmittance, vapor permeability, and resistance to vapor diffusion). Some indications on limits or reference/target values are usually given by national/regional laws and EU Directives. The filling insulation could lead to collateral problems (thermal bridges, risk of vapor condensation inside walls, etc.). To help understand the relevance and the impact of this insulation technique, an example of the assessments of a common cavity wall type is presented. The analyses highlight the usefulness of an organized and systematic database on building envelope features to set targeted energy-saving actions. Public administrations could base their strategies on this information to promote the reduction of energy consumption on a large scale with efficient and economically sustainable interventions. In the absence of more specific databases, the Energy Performance Certificates (EPC) data consulting could help develop thermal insulation strategies at a regional/national level. In particular, the diffusion of cavity walls can be obtained as a function of wall surface and cavity thickness for estimating the energy saving potential, economic impact, and general feasibility of systematic insulation-filling actions. An example of this kind of database analysis is discussed and carried out on a regional scale to explain how it could represent a useful approach to evaluate potential energy-saving interventions. The sample building stock provides suggestions on the possibility to extend the considerations on a larger scale to help set systematic energy-saving strategies.

Contamination Level Monitoring Techniques for High-Voltage Insulators: A Review

Insulators are considered one of the most significant parts of power systems which can affect the overall performance of high-voltage (HV) transmission lines and substations. High-voltage (HV) insulators are critical for the successful operation of HV overhead transmission lines, and a failure in any insulator due to contamination can lead to flashover voltage, which will cause a power outage. However, the electrical performance of HV insulators is highly environment sensitive. The main cause of these flashovers in the industrial, agricultural, desert, and coastal areas, is the insulator contamination caused by unfavorable climatic conditions such as dew, fog, or rain. Therefore, the purpose of this work is to review the different methods adopted to identify the contamination level on high-voltage insulators. Several methods have been developed to observe and measure the contamination level on HV insulators, such as leakage current, partial disgorgement, and images with the help of different techniques. Various techniques have been discussed alongside their advantages and disadvantages on the basis of the published research work in the last decade. The major high-voltage insulator contamination level classification techniques discussed include machine learning, fuzzy logic, neuro–fuzzy interface, detrended fluctuation analysis (DFA), and other methods. The contamination level data will aid the scheduling of the extensive and costly substation insulator, and live line washing performed using high-pressured water. As a result, considerable benefits in terms of improved power system reliability and maintenance cost savings will be realized. This paper provides an overview of the different signal processing and machine-learning methods adopted to identify the contamination level on high-voltage insulators. Various methods are studied, and the advantages and disadvantages of each method are discussed. The comprehensive review of the islanding methods will provide power utilities and researchers with a reference and guideline to select the best method to be used for contamination level identification based on their effectiveness and economic feasibility.

Experimental study on the thermal performances of a non-pump-driven thermo-activated building system based on flat-plate heat pipe array

• A non-pump-driven thermo-activated building system based on FPHPs is proposed. • Effects of tilt angles and heat loads on FPHP are experimentally investigated. • Preliminary performances of the FPHP-embedded wall are experimentally investigated. • The optimal tilt angle of FPHP is not a fixed value for building integration. • The measured U d is 0.19 and −0.08 W/m 2 °C when Ths is 25 and 35 °C, respectively. As a burgeoning active thermal insulation technique, the pipe-embedded building system has attracted particular attention from architects and engineers. A novel pipe-embedded building system based on flat-plate heat pipe (FPHP) is proposed to solve the inherent issues like operation energy consumption and façade integration. The experimental investigation is firstly conducted on an FPHP prototype to explore its thermal response characteristics at different tilt angles and heat loads and then performed on an FPHP-embedded composite wall to explore the preliminary thermal performances. Results showed that the length of the condensation section with uniform temperature distribution accounted for at least 88.9% when the heat load was smaller than 3000 W/m 2 , which verified the feasibility of using FPHP to complete the heat charging process. The tilt angle had a significant influence on the thermal resistances, startup behavior, and effective thermal conductivity of FPHP, and the optimal tilt angle could be reduced for load reduction mode, while this value could be increased for supplementary heating mode. When the heat source temperature is 25 and 35 °C, the equivalent heat transfer coefficient value of the FPHP-embedded wall under test conditions is 0.19 and −0.08 W/m 2 ·°C, respectively. Meanwhile, the corresponding heat loss reduction rate could reach 62.7% and 116.4%, respectively. Overall, the results evidenced the effectiveness of FPHP-embedded building systems, which could also contribute to its system design, operation control, and further investigation.

Low-cost DIY thermal upgrades for overheating mitigation in slum houses in Latin America & Caribbean

Over one billion of the world’s population live in slum houses (SHs), mostly self-built. Due to their poor construction and lack of mechanical cooling in hot regions, SHs are particularly vulnerable to overheating and ongoing climate change. This paper presents the overheating mitigation results of four selected DIY low-cost roof upgrades for a typical SH in Latin America & the Caribbean (LAC) to allow residents self-improvement. This study evaluates two insulation techniques and two natural ventilation devices, namely: a recycled Tetra Pak insulation board (TI), a radiant barrier, a cylindrical chimney, and a solar chimney, using a combination of experimental and numerical approaches that allow for increased reliability of the results, and widespread assessment of the impacts of the proposed strategies in several LAC locations under current and predicted future climates (2050). The results appointed the TI insulation combined with scheduled natural ventilation, as the most effective mitigation strategy, for less than 1€/m2, reaching a maximum improvement in the hottest cities of 3.1 °C of indoor operative temperature with an increased effect up to 3.3 °C in the 2050 scenario. Finally, this overheating mitigation solution is presented with an instruction manual to build and install it as an affordable SH upgrade.

Ensuring the seismic resistance of a building using a geotechnical seismic insulating screen

This paper considers the issue related to the protection of buildings and structures against seismic influences and the prevention, exclusion, or reduction of seismic hazards. The catastrophic destruction of modern «earthquake-resistant» buildings in Turkey and Taiwan has shown that existing methods of strengthening and reinforcing structures are not perfect and require further study. Analysis of existing approaches to ensuring seismic resistance showed that seismic insulation and seismic suppression systems still do not have a scientific and technical justification for the effectiveness of their operation from the point of view of ensuring the stability of structures. The estimation-dynamic models of the «base-seismic insulation-structure» system developed to date do not always make it possible to simulate the joint work of their interaction during an earthquake and account for the transformation of the seismic impact on the structure. An alternative technique has been devised, a geotechnical seismic insulation screen, as a seismic insulation system that reduces the intensity of seismic loads on the structure and ensures its seismic resistance. In a specific example, the effectiveness of this seismic insulation system is confirmed. This seismic insulation technique in the form of damper screens is characterized by reliability and manufacturability in ensuring the seismic resistance of objects under construction. The results of computational and experimental modeling of the interaction of an earthquake-insulated structure with a ground base found that the values of axial forces and bending moments in a building with a seismic insulating screen are less than in a building without seismic insulation by 30‒40 %. The geotechnical seismic insulation screen makes it possible to advance the development of new seismic insulation techniques and determine their effectiveness. This technique will also be effective when strengthening the base and seismic insulation systems of historical monuments, protecting them against seismic and dynamic influences.

Optimal positioning of phase change material and insulation through numerical investigations to reduce cooling loads in office buildings

Thermal comfort is inevitable in maintaining the healthy mood of the building occupants and hence increases their productivity. The main objective of this work is to identify the optimal positioning of Phase Change Material (PCM)/insulation techniques with respect to the building envelopes to enhance the thermal performance, thereby recommending effective techniques to reduce the cooling load demand of an office building located under different climates in India. Building models by integrating PCM and insulation layers at various locations of the building envelopes were developed using DesignBuilder software and investigated for summer conditions. The results were compared with that of the basic building. It is concluded that the buildings integrated with PCM or insulation at the outer walls exhibited comfortable indoor temperatures than those integrated at the innermost walls, irrespective of the building location. The selection of PCM and insulation for any location is to be made depending upon the average external temperatures of that specific location for effective and enhanced performance. Based upon the average external temperatures, appropriate techniques were recommended for buildings in different climates. Compared to basic building, the recommended buildings yielded a cooling load reduction of 64%, 61%, 57%, 63%, and 58/59% for Bangalore, Delhi, Jodhpur, Pune, and Guwahati.

Investigation of Intelligent Substation Inspection Robot by Using Mobile Data

Substation equipment inspection is essential for the power industry. The expansion of the smart grid scale improves the transmission capacity and enhances the likelihood of power plant facilities failure. To ensure the safety of the electric power supply, it is essential to inspect substation equipment. Metal commercial equipment can be traversed by remote inspection robots equipped with magnetic wheels. It is possible to use robots like this to examine equipment and pipelines remotely. In many cases, these gadgets are able to scale vertical surfaces and even traverse obstacles with a variety of shapes. Finally, researchers in the field of robotics have indicated that challenges such as restricted onboard battery capacity, undependable line fault detection, electrical insulation, power mechanism, and advanced control techniques for outer wind disruption are highly promising research areas. To build an unmanned, intelligent, and succeeded substation, the substation progressively implements inspection robots instead of physical exertion. Hence, in this paper, the mobile-based Intelligent Tracking Framework (MITF) has been proposed using inspection robots. This inspection robot is autonomous and can be used for various tracking tools: visual, infrared, and partial charge–discharge camera. The robot is integrated with a camera and thermal infrared imager sensors that have been collectively designated as workload. These inspection sensors are used to detect environmental parameters such as reading meters, evaluation thermoelectric temperature. The accurate localization of working loads and the inspection robot electromagnetic interference within substations have been resolved. This mobile robot delivers innovative monitoring and precise detection for the unmanned substation and smart substation. The suggested approach’s effectiveness is verified through experiment results based on the electrical equipment of the substation. The experimental outcome of the proposed method boosts the Meter Reading Analysis (94.19%), Transmission Capacity Analysis (98.5%), Workload Analysis (98.9%), Temperature Analysis (97.6%), and Safety Analysis (95.41%).

Thermal insulation and mechanical characteristics of cement mortar reinforced with mineral wool and rice straw fibers

Building insulation is an essential requirement for buildings located in areas of varying temperature conditions. However, the conventional building insulation techniques accrue high cost and consume resources. This work aimed to evaluate the use of mineral wool and rice straw to improve Portland cement mortar's thermal insulating properties. Samples of 40x40x160 mm mortar were produced with cement and sand, but varying mineral wool and rice straw constituents from 0 to 50% in weight. Water absorption, flexural and compressive strengths, thermal conductivity were performed in samples with and without mineral wool and rice straw addition. The microstructure of mortars was analyzed using scanning electron microscopy (SEM). It was observed that reinforcing mortars with mineral wool and rice straw fibers yielded a significant drop in the mortar's thermal conductivity, improving their insulative abilities. Although the addition of fibers, in turn, deferred the mechanical performance in some mixes, however, it was not too significant or below workable standards. The performed tests prove the feasibility of adopting the selected fibers for insulating Portland cement mortars.

Evaluation of environmental and economic implications of a cold‐weather aquaponic food production system using life cycle assessment and economic analysis

AbstractAquaponics, in which fish and plants are grown in a symbiotic closed‐loop industrial metabolism, are promising test beds to implement industrial ecology in food production at a commercial scale. These systems have the potential to enhance the environmental and economic performance of aquaculture systems by reducing the overall burden on natural ecosystems (i.e., reducing resource and emission‐based impacts per unit of food produced). To holistically evaluate the environmental and economic implications of aquaponics, specifically in a cold‐weather climate, Life Cycle Assessment (LCA) and Economic Analysis (EA) were performed on a Midwestern United States aquaponic system, using data from 3 years of annual operation cycles with varying fish species production; tilapia, conventional walleye, and hybrid walleye. For the LCA, environmental impacts were quantified using 10 midpoint indicators. Assessments indicated that 1‐kg production of live‐weight tilapia, conventional walleye, and hybrid walleye resulted in 20.2‐13.8‐11.7 kg CO2‐eq, 23.0‐7.8‐3.9 g N‐eq, and 0.2‐0.3‐0.4 kg SO2‐eq, consecutively, using the investigated system. The most sensitive parameters for environmental impacts were heat, aquafeed, electricity, and infrastructure (in all scenarios). For EA, benefit to cost ratios (BCRs) and three other widely used indices were analyzed for production cycles. The BCRs were 0.47, 1.16, and 1.75 for tilapia, conventional walleye, and hybrid walleye, respectively (using a 10% discount rate and a 20‐year horizon), highlighting the necessity of optimizing both cash inflows (e.g., energy costs) and outflows (plant and fish revenues) to achieve practical enhancement of return on investments. The major cost contributors were infrastructure, labor, and heat (contributing to >89% of total costs for all cycles). Suggested steps for in‐effect improvement of the investigated aquaponic system's environmental and economic favorability include heat and infrastructure optimization by (a) applying effective heating strategies (e.g., advanced insulation techniques), and (b) expanding the system's operational lifespan (e.g., prevention of waste accumulation).

The impact of efficient insulation on thermal performance of building elements in hot arid region

The application of thermal insulation technique for buildings in hot arid region still under development and requires investigation for many aspects, especially those related to the individual elements of the construction. The present study investigates the impact of efficient insulation on the thermal performance of the following construction elements: wall, roof and foundation. The techniques used for the insulation have followed the Passive House criteria. The study introduces many benefits for passive design of the building in extreme hot climate. The work has done experimentally in Kirkuk, Iraq for two building models; one is efficiently insulated and the other is traditional. The data, which are collected in summer time, show reduction in indoor temperature of the efficient model by 8 °C in average comparing to that of traditional one. Measurements show stability in the internal wall temperatures for efficient model with an average temperature of 33 °C comparing to 42 °C for traditional one. Similarly, the insulated roof radiates less heat into the indoor than that of traditional model. Furthermore, the effect of both efficient insulated roof and canopy shading reduces the temperature of internal surface temperature of the roof by 12 °C comparing to the traditional model. A local simulation program based on ASHRAE relations has shown an energy saving in the cooling load up to 70%.

Improving thermal performance of existing uninsulated R.C. domes through passive cooling measures using polyurethane foam in double skin layer in hot climate.

Thermal insulation is a significant issue of building sustainability. Facades and roofs represent the exterior envelop of buildings. One of the weakest points in roof insulation is dome. Most of the domes in Saudi Arabia are thermally uninsulated due to the absence of practical insulation techniques. This paper concerns solving the problem of thermally uninsulated R.C. domes. A selected zone in Al-wali district in Makkah has around 68 thermally uninsulated R.C. domes made of 150 mm R.C. dome roof, 25 mm mortar layer with acrylic thermal emulsion paint from outside, and 3 mm gypsum plastering from inside. This construction has low thermal resistivity value (U-value = 10.3627 W/m2K) exceeding region code of 0.31 W/m2K. Three options were tested on three similar uninsulated domes. Firstly, creating 50 mm foam concrete layer covered by light acrylic ceramic microspheres-based for weather protection, an option that has been widely used by most owners. Secondly, creating 75 mm polyurethane foam layer covered by acrylic ceramic microspheres-based paint, an option that has difficulty in external cladding, maintenance, and aesthetic value. Thirdly, creating double-skin layer reinforced by 220 mm vertical steel bars, consisting of 75 mm polyurethane foam with an external cladding of 6 mm ceramic tiles, an option suggested by this paper based on most owners' preferences since it controls heat transfer and allows external cladding. Difference in temperature (ΔT) between inside and outside the three treated domes were reported using surface infrared laser thermometer. Option 1 was practical and economical, but ineffective (U-value =2.5445 W/m2K, ΔT= 5.8 ֯C). Options 2& 3 were almost similar, both were effective and satisfy area code (U-value =0.2949, 0.2920 W/m2K, ΔT= 14.3, 14.8 ֯C respectively).

A pathway towards healthy and naturally ventilated indoor built environment through phase change material and insulation techniques for office buildings in India

The thermal comfort of occupants is a necessary requirement for any building. The present pandemic demands us to opt for natural ventilation over air-conditioned spaces to reduce the spread of the infection. This work aims to prevent air-conditioner usage in a commercial building in India during daytime office hours while simultaneously enhancing the thermal comfort of the building occupants through natural ventilation/Phase Change Material (PCM)/insulation techniques. Four building configurations, such as Building A (conventional building with no PCM and no insulation), Building B (building-integrated with PCM), Building C (building-integrated with insulation) and Building D (building-integrated with PCM and insulation) were analysed for various locations using DesignBuilder software. From the results, it is understood that insulation integration is recommended for locations with average nighttime temperatures greater than 27°C, while PCM integration is recommended for locations with an average nighttime temperature less than 27°C during the summer season. Also, nighttime cooling of the building through an air-conditioner is necessary for all locations during summer to maintain adequate thermal comfort with natural ventilation in the daytime. Finally, an appropriate PCM/insulation technique is recommended for an office building located in each location that falls under each type of climate. Hence, the selection of PCM/insulation technique is to be made based on the specific site conditions.

Energy and Environmental Evaluation of Retrofitting Facades for Zero Energy Buildings: The Case of an Office Building in Greece

Energy and environmental targets are expressed clearly by the EU policies setting ambitious goals for 2030 and 2050 considering energy intensive sectors such as buildings. Pursuing high energy performance with the least environmental impact of a building, along with ensuring the well-being of the occupants, is the ultimate goal of an institutional framework that addresses energy efficiency and environmental sustainability. Part of this effort is the improvement of the building envelope’s thermal performance, along with the respective one of HVAC systems, as those determine thee energy performance of buildings in their use phase. Main scope of the paper is to evaluate and analyse different scenarios considering the retrofitting of facades as part of the refurbishment towards Zero and Positive Energy Buildings, but also in connection with the strive for Net Zero Energy, Net Zero Cost Energy and Net Zero Emissions goals. The paper also discusses energy and environmental evaluation of refurbishing an office building in Greece, examining the performance of different envelope construction typologies and alternative insulation scenarios. These scenarios include state of the art insulation techniques, but also innovative design elements such as the use of different final coating materials for ventilated façades like the use of phase-changing materials (PCMs). The results of the assessment undertaken are used to rate the construction solutions by means of energy and environmental parameters proving the environmental impact of concrete and insulation materials in construction phase but also the reduced primary energy consumption and thus the CO2 emissions in the life cycle of the building. Considering the environmental evaluation, the carbon footprint analysis was used according to Greenhouse Gas Protocol focusing mainly on CO2 emissions, which is the main emission target of EU policies. The impact assessment followed demonstrated that the most significant impact categories are global warming, acidification and eutrophication.

Coupling methods and optimal use of modern anti-seismic insulation systems at building and bridge construction structures

The construction industry has recorded an unprecedented advance in recent years, especially in the world recent developed countries and this involves the increasing development of insulation techniques against the effects of seismic actions that can threaten the structure integrity at a certain time. Most recent achievements in terms of structure insulation systems are successfully used within building and bridge structures in order to ensure the optimal stability level during a potential earthquake, which allows ensuring a proper safety level both for operation and in terms of investments protection. the protection methods of the structures are directed in two directions, namely in achieving the insulation at the base of the structure by strategically positioning the systems at the base of the structure while the second direction is directed at seismic energy consumption or energy dissipation by using dissipative systems mounted on frames the resistance structure of the building. By combining the action of the two types of mechanical systems, good results can be obtained regarding the behaviour of the structure isolated by the earthquake. The paper presents constructive aspects of the mechanical systems used for the seismic insulation of both building and bridge structures and their functional role in the whole structure to which they are mounted. Through the experimental tests made are highlighted the better results in terms of acceleration for the structure isolated with the composed system. Are emphasized in this manner the protective system role in ensuring an improved behaviour for the structure where is mounted at seismic dynamic motions that can occur in time.

Evaluating the Impact of Indoor Insulation on Historic Buildings: A Multilevel Approach Involving Heat and Moisture Simulations

The energy refurbishment of historic buildings is a complex task for building envelope designers who need to carefully consider building conservation guidelines and principles. In most cases, external wall insulation techniques can determine an unacceptable alteration of the historical value of a building. For this reason, internal wall insulation techniques have been used widely in the last few decades. Nevertheless, dealing with internal wall insulation requires a complex design to avoid the risk of condensation and moisture-related pathologies. Moreover, an internal wall insulation may have a relevant impact on indoor comfort conditions. In this paper, the Monastery of Santa Maria de Monfero in Galicia (Spain) has been adopted as a building case study to compare different technological solutions based on: (i) an insulating plaster layer, (ii) dry counter wall systems. In the first step, heat and moisture transfer simulations of the wall components were performed to analyze the hygrothermal behavior of the different alternatives considering two different climate conditions. In a second step, a simulation of the whole building was performed to analyze the impact of the retrofitting strategies on the indoor climate and on the building heating and cooling demand. The obtained results show that the counter wall solution leads to higher energy savings during the heating season in the colder winter climate. However, the use of insulating thermal plaster could also be a viable solution since they lead to several advantages in summer because of their higher thermal inertia. Therefore, the selection of the most appropriate insulation technique has to be evaluated carefully considering the outdoor/indoor climate and using a case-by-case approach.

Effect of Three Different Cooling and Insulation Techniques on Pulp Chamber Temperature during Direct Temporization with Polymethyl methacrylate-based Resin

This in vitro study evaluates and compares the changes in pulp chamber temperature during direct fabrication of provisional restorations in maxillary central incisors after using three different cooling techniques. Total of 60 samples of maxillary central incisors along with their putty indices were divided into four groups (one control and three experimental) and were prepared using a surveyor cum milling machine. Teeth were sectioned 2 mm below cementoenamel junction and a K-type thermocouple wire was inserted in the tooth and secured at the pulpal roof using amalgam. Putty index filled with DPI tooth molding resin material [polymethyl methacrylate (PMMA)] was placed on the tooth and temperature changes per 5 seconds were recorded by temperature indicating device for the control, on-off, precooled putty, and dentin bonding agent (DBA) group. The highest mean obtained was of the control (11.04°C), followed by DBA group (9.53°C), precooled putty group (6.67°C), and on-off group (1.94°C). Precooled putty index group took maximum time to reach the baseline temperature (847.5 seconds). On-off technique is the most effective method to reduce the intrapulpal temperature during polymerization, as compared to the other techniques used in the study. Retardation in the polymerization process was seen in precooled putty group, which may make this technique clinically inadvisable. Thermal protection of pulp must always be considered during direct fabrication of provisional restoration when a PMMA-based resin is used. By using on-off technique, not only the thermal insult to the pulp can be effectively minimized but also the harmful effects of residual monomer (poor marginal fit and pulpal irritation) can be eliminated.

Analysis of Multistoried RCC Building with Shear Wall and Outrigger using ETABS Software

During earthquakes, a large number of buildings are destroyed due to the cause of lateral forces and increased load capacity in the structural element, and this is caused by winds, earthquakes and uneven settlement of cargo. The least damage and well-being a healthy level of construction is a necessary requirement for tall buildings. To reduce the impact of damage on all high structures, it may consist of basic insulation techniques and sliding walls, and so on. Buildings are used to increase design performance and limit damage to landslide walls. On tall buildings to prevent earthquake loads, reinforced concrete walls are used as supporting elements. Reinforced concrete structures are mainly implemented in engineering practice in different situations and different applications. Many researchers turn to the effectiveness of sliding walls with boundary conditions based on different types of reinforcement alignment. This document consists of modeling different models for the shear wall housing and the hood system.