Selection Of Insulation Materials Research Articles

Determination of Appropriate Overhead Line Insulator in Sumatra due to Contamination Severity

Insulator is one of the important equipment to support electrical power delivery which flow through the transmission line. Considering its very important role, the selection of insulators must be certainly based on deep analysis so that the insulator we choose works properly. There are several standards that can be used in selecting isolators, but in this paper the standards that will be used for case study analysis are IEC and IEEE standards. Case studies that will be used for the selection of insulators are for Sumatra that located in Indonesia which is a tropical country and certainly has special environmental characteristics that can influence the selection parameters of an insulator. There are several parameters that are commonly used in selecting overhead isolators those are power frequency voltage, environmental condition (contamination), switching over voltage, and lightning over voltage. Using environmental condition, it is found that the pollution category of Sumatra area is heavy, which influence the selection of insulation material.

Electric Field and Energy Losses of Rounded Superconducting/Ferromagnetic Heterostructures at Self-Field Conditions

The ac losses induced by an alternating transport current in type-II superconductors is a well-known phenomenon, which still attracts much attention because of its intrinsic relevance for the proper development of practical applications. In the case of single core superconducting cables of cylindrical cross-section, it is possible to find exact analytical solutions at self field conditions, and it has been believed for nearly two decades that the use of an ideal soft ferromagnetic sheath with negligible magnetization losses will not affect the electromagnetic properties of the superconducting wire, and on the contrary due to the shielding magnetic properties of the ferromagnet, the total ac losses of the SC wire have to be reduced or as maximum they must be equal to the one for the bare superconductor at self-field conditions, what contraries the experimental evidences that show a non-negligible increase on the ac losses. In this paper, we explain the physical nature of this mysterious increase in the ac losses for rounded superconducting/ferromagnetic heterostrutures, which for the sake of generality, has been solved within the critical state theory, and a magnetic multipolar expansion that enables the direct coupling of the magnetostatic properties of the superconductor and an ideal soft ferromagnet. A significant increase in the transient electric field during excitation period has been observed, which might have utter implications on the adequate selection of insulation materials for superconducting/ferromagnetic heterostructures.

Dielectric Losses in Dry-Type Insulation of Medium-Voltage Power Electronic Converters

Newly available medium-voltage (MV) silicon carbide (SiC) transistors are setting new limits for the design space of MV converters. Unprecedented blocking voltages, higher switching frequencies, higher commutation speeds, lower losses, and high temperature operation can be reached, which, however, create new challenges for the electrical insulation. In particular, the dielectric losses can become significant for MV converters operated at higher switching frequencies. Moreover, the evaluation of the dielectric losses is a key element for assessing the insulation stress and for insulation diagnostics. Therefore, this paper analyzes the modeling and the computation of dielectric losses with pulsewidth modulated (PWM) voltages. After a review of the dielectric loss mechanisms occurring in polymeric insulation materials, scalable analytical expressions are proposed for the losses produced by PWM voltages. Afterward, the dielectric losses of a medium-frequency (MF) transformer, employed in a 25 kW MV dc-dc converter (7 kV-400 V) operated at 48 kHz, are analyzed and measured in detail. With epoxy resin, the insulation losses represent a significant share, i.e., up to 17%, of the total transformer losses. As shown, the transformer performance can be significantly improved with silicone elastomer insulation. Finally, design guidelines are provided for the selection of insulation materials.

Energy saving and optimum insulation thicknesses in building upgrading

Heat pumps are classified as ecologically friendly heat-generating devices and are one of the most suitable solutions for improving energy efficiency in buildings. Systems based on such solutions replace conventional sources very well. Household sector is one of the major energy consumers, where energy is used mainly for space heating and providing hot water. To increase renewable energy consumption levels, it is necessary to take decisive actions aimed at energy modernization of existing buildings. Particular emphasis must be put on the use of renewable energy sources. A wide selection of insulation materials is available on the market, however proper technologies are required to apply those materials, especially for historical buildings. Therefore, while planning investment, a question must be answered what type of material should be used, and what costs that will generate. The paper presents simple methodology for calculating the optimal insulation thickness so that the costs of the thermo-modernization would be covered by savings in heating expenses, when bank loan for the project is available at fixed interest rate.

Nonlinear benefit-cost optimization-based selection of insulation material and window type: A case study in Turkey

In this study, we maximize the energy savings of a hypothetical household by choosing an optimal insulation material with its optimal thickness and also the optimal window type. We develop a nonlinear mixed integer optimization model that maximizes the net present value of the benefits obtained by insulation over the lifespan of the house. Savings are calculated based on the gains from the electricity usage for air conditioning during cooling-required days and the fuel usage for heaters in heating-required days. The heat transfer calculations consider conductive, convective, and radiative components simultaneously. The optimization model takes the climate conditions of the region where the house is located, the consumer's desired indoor temperature, and the properties of the insulation options; then, it returns a combination of selected insulation materials with its optimum thickness and window type as output. We applied the optimization model developed to hypothetical houses in four different climatic regions of Turkey for different lifespans. For all reasonable lifespans, the model choses stonewool as the ideal insulation material. For high interest rates, single windows or double-glazed windows are preferable, but as the interest rate decreases and the net present value of the energy-savings increases, the model prefers triple-glazed windows as the ideal material. Erzurum, a city in climatic region 4, characterized by very cold winters and cool summers, was found to require the highest optimum insulation thickness, and the economic return resulting from the above-mentioned energy-saving actions was also found to be the highest in the case of Erzurum. In all the regions, the energy-saving investments were found to be feasible via applying the feasibility assessment techniques of net present value and payback period. The model developed in this study is applicable to any household as long as the required input data are available.

Geometric effect in a vertical stack-up metal-insulator-metal tunnel diode

The geometric effect was investigated in a vertically designed metal-insulator-metal (MIM) tunnel diode for which a narrow tunneling distance can be controlled easily and reliably, with the goal of enhancing rectifying efficiency, based on the angle of a pointed shape electrode and various thicknesses of insulator material. Although MIM tunneling diodes can provide ultra- high working speeds (>THz), the very low contrast ratio between forward and reverse currents results in poor rectifying efficiency. An asymmetric geometry design with two metal electrodes can be an effective approach for enhancing the contrast ratio between the tunneling currents. Using a sharp electrode with a pointed shape, it was determined that the rectifying efficiency and tunneling probability could be increased impressively depending on the angle of the pointed shape of the electrode. Moreover, the selection of insulation material was also important for improving efficiency. Although the band gap of Al2O3 is larger than that of HfO2, the rectifying efficiency was significantly improved by blocking reverse current well. In general, large band gap insulator materials are inappropriate for a tunneling device, due to the low tunneling current. However, in our approach, since the issue of low tunneling probability is compensated by the sharp tip structure, the larger band gap insulator produced better rectifying efficiency with the appropriate current density. The results of this study demonstrated that geometric design could be a possible solution to increase rectifying efficiency. If the geometric effect in the tunneling diode structures will be optimized more, it can improve the applicability of vertical stack-up MIM tunnel diode to THz switching devices, tunneling transistors and ultra-high speed electronics.

Optimum Insulation Thickness for the Exterior Walls of Buildings in Turkey Based on Different Materials, Energy Sources and Climate Regions

Thermal insulation improves the strength and longevity of buildings by reducing energy consumption, and as a related result, improved energy use. The selection of insulation material is governed by important parameters, including the average outdoor air temperature, the thermal conductivity of the buildings and the cost of the insulation material. Increases in the thickness of the insulation material will gradually decrease the energy consumption for heating; however, the insulation thickness has an optimum value that minimises the total investment cost, and determination of this optimum value is critical for economic analysis. In this paper, a life-cycle cost analysis is presented to show the optimum insulation thickness, energy savings over a lifetime of 15 years and payback periods for six different fuels and insulation materials for four cities in Turkey selected from climate regions identified by the Turkish Thermal Insulation Standard (TS 825). Mugla (1st region), Kocaeli (2nd region), Ankara (3rd region) and Ardahan (4th region) were selected for analysis of a sandwich-type wall constructed from the following six insulation materials: extruded polystyrene, expanded polystyrene, glass wool, rock wool, polyisocyanurate and polyurethane. The calculations were also made on the basis of six different fuels, such as motorin, natural gas, propane (LPG), electricity, coal (imported), and fuel-oil No. 4. As a consequence, results demonstated that the optimum insulation thickness vary between 2.8 cm and 45.1 cm, with energy savings between 16.4 ₺ /m 2 and 479 ₺ /m 2 , and payback periods fluctuating between 0.078 and 0.860 years, depending on the city, the insulation material, and the cost of fuel.

SELECTION OF THE INSULATION MATERIALS FOR REFURBISHMENT PURPOSES

Refurbishment of the building facades of residential buildings, including insulation, is often considered as the most energy efficient renovation measure with the largest potential. One of the solutions to increase energy efficiency is the selection of the appropriate insulation materials of the external walls. The article proposes the approach for selection of the insulation material based on SAW multiple criteria assessment method. The proposed methodology is applied for the case of insulation material selection in refurbishment of 12-storey building in Vilnius, Lithuania. Research reveals that rock wool outperforms other materials by thermal conductivity, light weigh, water vapour diffusion resistance, highest flammability class, durability and lowest emission of CO2 and is an efficient insulation to be used for sustainable refurbishment solutions.

Selection of Insulation Material for Solar Food Grain Disinfection System by Weighted Property Method

Selection of Insulation Material for Solar Food Grain Disinfection System by Weighted Property Method

Selection of Insulation Materials and Insulation Performance with Consideration of Building Energy when Designing a Building

Building designs should be reviewed from the aspects of both design aesthetics and energy performance. The installation of insulation materials in external walls, roofs, and floors is a basic method that could reduce energy losses from buildings. The purpose of this study is to investigate the types of insulation materials selected as building materials and the insulation performance of each building elements when designing new buildings in South Korea. The insulation performance of the external walls, roofs, and floors of buildings were compared with the insulation criteria of the Energy Saving Design Standards of Buildings in building energy code. The design documents, as well as drawings and building energy saving plan sheets, which are required to be submitted for buildings larger than a certain size in South Korea, were collected. The most widely used insulation material in multi-family housings and non-residential buildings was extruded polystyrene (XPS). The insulation performance of external walls, roofs, and floors were higher than that established by design criteria of building energy code. In particular, the external walls had roughly a 25.5% better insulation performance than the insulation criteria.

Life-cycle assessment and control measures for carbon emissions of typical buildings in China

The construction industry plays an important role in economic and social development, yet it is also a primary source of carbon emissions. Accordingly, owing to global climate change, energy conservation and carbon reduction have become critical issues in the construction industry. However, to date, no established theory has been proposed for the life-cycle carbon assessment of typical buildings in China. To address this, the present study proposes a detailed carbon emission inventory for buildings and divides the life-cycle of a typical building into three stages based on material and energy flow: the materialization stage, the operation stage, and the disposal stage. Additionally, an analytical framework and evaluation indices are established and the proposed methodology is applied to three case studies. The results demonstrate that residential and office buildings with a reinforced concrete block masonry structure could reduce carbon emissions by 38–112 kgCO2/m2 compared with either a reinforced concrete structure or a brick–concrete structure. Although the operation stage appears to contribute approximately 82–86% of the total emissions, the materialization stage is also of considerable importance in alleviating the present environmental pressure. Furthermore, possible measures to control carbon during the materialization stage are proposed and evaluated, including optimization design of building structures based on carbon emissions and the selection of insulation materials. Accordingly, this study provides a standard method for life-cycle carbon assessment of buildings, which will be critical for future low-carbon development.

Assessment of the Methods of Electrical Energy Rationalization in Kuwaiti Mosques using Hourly Analysis Program (HAP)

The energy crisis, especially electricity consumption, is a crisis that plagues the world in general and Kuwait in particular. The Ministry of Electricity and Water in Kuwait (2009) said that the high temperature in the summer months, sometimes reach to 50 degrees Celsius in the shade, leads to increase demand in the air-conditioning loads. The study aims to assess the methods of electrical energy rationalization in Kuwaiti mosques using the simulation software (HAP). Since the mosques are located in separate areas of Kuwait and operate simultaneously, one of the mosques was selected as an example to find the best way to conserve energy. The results showed that, there are several possible ways to reduce the air-conditioning loads. Replacement incandescent bulbs with the energy-saving bulbs, installing programmable thermostat technology and control the infusion rate, lead to energy savings up to 32%, 2.9% and 11.4% respectively. The study also demonstrated the impact of other ways in reducing the rate of consumption, as: area of glass (1.7%), direction of the building (2%), the heat transfer coefficient of the building and the windows (11.4%) and outside color of the building (4.2%). Moreover, the wall color is more influential than roof color and the selection of insulation material and thickness is very important as it reduces cooling load up to 35%. All of these factors may help in lowering the rates of energy consumption in mosques and hence contribute in the reduction of greenhouse gases and pollutants.

Insulation Measurement System Design and Implementation

Insulation measurement system performance influence of insulation material selection formula as well as the material production and quality. This paper introduces the insulation performance measuring system and control theory, and the ablation experiments of main technical parameters and data processing and insulation material performance evaluation standards: adiabatic index, the linear ablation rate, mass loss rate calculation and evaluation.

Building External Wall Thermal Insulation Construction Quality Safety Measures Analysis

The external wall thermal insulation technology in building energy saving is widely used in engineering, but in general it faces some quality security problems, this paper insulation material selection, exterior insulation system and its safety, fire redundancy and external wall construction corresponding measures on the analysis. So as to the engineering quality safety problems have prevention in the role of the external wall thermal insulation technology obtain the considerable development.

Analisis Rugi-Rugi Panas pada Tangki Penyimpan Panas dalam Sistem Pembangkit Listrik Tenaga Matahari

Analysis of heat loss on heat storage tank in solar power generation system is intended to determine the heat loss value during storage. Selection of insulation material, insulation thickness, time of storage and heat storage fluid affects the heat losses. The research was initiated by determining the dimension of the tank and its insulation material, and determining the heat storage time in the tank. Fluid and operating temperature is determined to get the fluid specification to be used as data analysis. The analysis begins with the calculation of storage capacities, followed by making of thermal nets to get the thermal resistance equation which is then used to calculate the heat loss in the tank. The result shows that the heat storage tank with 0.4 m diameter and 0.45 m height and uses ceramic fiber wool insulation with 0.1m thickness gives the value of heat loss of 63.43 W.

A Practical Cost Model for Selecting Nonwoven Insulation Materials

Elementary heat transfer in the range of density, thickness, and temperature normally used for house insulation, has been described experimentally for nonwoven structures. A model relating cost, density, and thermal efficiency of nonwoven insulating materials has been developed to aid in insulation materials selection and optimization of cost. Intrinsic to this system are material specific thermal conductivity slope coefficients readily derived from thermal conductivity versus specific volume plots.

Taking the Pulse of Subsea Trees Design towards Deepwater Application

The challenges facing the subsea production system are becoming increasingly complex with hydrocarbon production moves into deep and even ultra-deep waters. As the most critical equipments, subsea trees need to be designed synchronously against the increasing technology gaps. This paper highlights the common considerations for subsea trees design, especially the horizontal Xmas tree, towards future deepwater application, and the main contents consists of structure design combined with subsea seal technology and the important thermal design in terms of insulation materials selection and application, numerical simulation. Meanwhile, some suggestions and application cases are also included in this paper.

Insulation Materials Selection for Passive Evaporative Cooling Roof in Buildings

The passive evaporative cooling roof in building is an important passive thermal insulation technology with the development of green roof, spraying water roof and storing water roof. For its complexity of heat and moisture transfer process only some sample experiments could be done on some controlling conditions. In this paper on the basis of analyzing the unsteady heat transfer model with the first boundary conditions and by using the integral method based on the concept of thermal boundary layer the critical penetration time, the critical penetration thickness and the temperature attenuation ratio are calculated and analyzed for different materials with different thickness. The research results show that the critical penetration time is gradually attenuated with the increasing of thermal diffusivity. The critical penetration time of being researched materials is lower than one hour when the thickness of materials is 0.1 meter, when the thickness of materials is 0.2 meter the critical penetration time is between 46.83 and 214.55 minutes, when the thickness is 0.3 meter the time is between 105.36 and 482.73 minutes. The sandy soil has the maximal critical penetration time and the critical penetration thickness in all analyzed materials, and the loose sawdust has the minimum critical penetration time and the maximal critical penetration thickness. On the side of temperature attenuation ratio the different material thickness has different attenuation law.

Mechanical Behavior of Syntactic Foams for Deep Sea Thermally Insulated Pipeline

Ultra Deep offshore oil exploitation (down to 3000 meters depth) presents new challenges to offshore engineering and operating companies. Flow assurance and particularly the selection of insulation materials to be applied to pipe lines are of primary importance, and are the focus of much industry interest for deepwater applications. Polymeric and composite materials, particularly syntactic foams, are now widely used for this application, so the understanding of their behavior under extreme conditions is essential. These materials, applied as a thick coating (up to 10-15 cm), are subjected in service to: - high hydrostatic compression (up to 30 MPa) - severe thermal gradients (from 4°C at the outer surface to 150°C at the inner wall), and to high bending and shear stresses during installation. Damageable behavior of syntactic foam under service conditions has been observed previously [1] and may strongly affect the long term reliability of the system (loss of thermal properties).This study is a part of a larger project aiming to model the in-service behavior of these structures. For this purpose it is important to identify the constituent mechanical properties correctly [2, 3]. A series of tests has been developed to address this point, which includes: - hydrostatic compression - shear loading using a modified Arcan fixture This paper will describe the different test methods and present results obtained for different types of syntactic foams.

Polyamide 66 as a cryogenic dielectric

Improvements in superconductor and cryogenic technologies enable novel power apparatus, e.g., cables, transformers, fault current limiters, generators, it etc., with better device characteristics than their conventional counterparts. In these applications electrical insulation materials play an important role in system weight, footprint (size), and voltage level. The trend in the electrical insulation material selection has been to adapt or to employ conventional insulation materials to these new systems. However, at low temperatures, thermal contraction and loss of mechanical strength in many materials make them unsuitable for superconducting power applications. In this paper, a widely used commercial material was characterized as a potential cryogenic dielectric. The material is used in “oven bags” which is a heat-resistant polyamide (nylon) used in cooking (produced by Reynolds ® , Richmond, VA, USA). It is first characterized by Fourier transform infrared and X-ray diffraction techniques and determined to be composed of polyamide 66 (PA66) polymer. Secondly the complex dielectric permittivity and dielectric breakdown strength of the PA66 films are investigated. The dielectric data are then compared with data reported in the literature. A comparison of dielectric strength with a widely used high-temperature superconductor electrical insulation material, polypropylene-laminated paper ( PPLP ™ a product of Sumitomo Electric Industries, Japan), is provided. It is observed that the statistical analysis of the PA66 films yields 1% failure probability at 127 kV mm - 1 ; this value is approximately 46 kV mm - 1 higher than PPLP ™ . Comparison of the mechanical properties of PA and PPLP ™ indicates that PA66 has low storage and loss moduli than PPLP ™ . It is concluded that PA66 may be a good candidate for cryogenic applications. Finally, a summary of dielectric properties of some of the commercial tape insulation materials and various polymers is also provided.