Reflective Insulation Research Articles

원전 설비 열차폐를 위한 반사형 금속단열재의 내진 해석

원전 설비 열차폐를 위한 반사형 금속단열재의 내진 해석

Verification of the thermal insulation properties and determination the optimal position of the reflective thermal insulation layer in the wood based envelope

Abstract To achieve thinner wood based envelope is necessary look for an alternative thermal insulation material, which will have the best possible thermal insulation properties while maintaining affordability. One such material is also reflective thermal insulation layer, but it is necessary to verify the thermal insulation properties and determine the optimal position in the wood based envelope.

Insulation-Affecting Factors of Low-Emissivity Insulation

Low-Emissivity Insulation has enclosed reflective air spaces between aluminum foils that have very low emissivity. The reflective air spaces are composed of optimum-sized air cells, which are enclosed by polyethylene foam. The critical difference between Low-Emissivity Insulation and conventional reflective insulation is the presence of a honeycomb structure formed from polyethylene that serves as the core material. Low-Emissivity Insulation has a foil surface emissivity of 0.04 with enclosed air cells between foils. Its core material is polyethylene foam with 35 times expansion, which is expanded to make air cells. The enclosed air cells with foil reduce convective and radiative heat transfer. To verify the high efficiency of Low-Emissivity Insulation, it was tested by an accredited laboratory designated by the Korean government. Comprehensive thermal transmittance tests were conducted for the Low-Emissivity Insulation of specimens of various thicknesses. The thicknesses of the specimens were 10, 20, 30, 40, 50, 60, 80, and 100mm. Based on the test results, its insulation-affecting factors were investigated using a trial-and-error method.

Hybrid and Reflective Insulation Assemblies for Buildings

Materials with a low thermal emittance surface have been used for many years to create reflective insulations that reduce the rate of heat flow across building envelopes. Reflective insulation technology is now being combined with other energy conserving technologies to optimize overall thermal performance. The basis for the performance of reflective insulations and radiant barriers will be discussed along with the combination of these materials with cellular plastic or mineral fiber insulations to form hybrid insulation assemblies. Calculations of thermal resistance for enclosed reflective air spaces and current field data from Southeast Asia will be presented. These data show that reductions in heat transfer across the building enclosure can be effectively reduced by the use of enclosed reflective air spaces and attic radiant barriers. Reflective technology increases the overall thermal resistance of the building enclosure when used to insulate poured concrete structures.

The Effect of Exterior and Interior Roof Thermal Radiation on Buildings Cooling Energy

Residential buildings in Iraq consume 42% of the country's total electricity production. As residential air-conditioning usage increases, so does the demand on the country's electrical power infrastructure resulting in more frequent power cuts and rolling blackouts. This research investigates the effectiveness of applying a reflective roof, radiant barrier and interior radiation control coating to reduce the space cooling loads of Iraqi houses and in turn electricity demand. Findings from this study's preliminary energy simulations indicate that external roof coatings, internal coatings, and radiant barriers can provide a significant reduction in cooling load compared to the typical roof finishes of Iraqi houses therefore potentially reducing the energy demand on the country's energy infrastructure.

Compare of Experimental and Numerical Evaluation of Structure with Application of Reflective Insulation

Thermal insulation effect of reflective insulation is based on the reflection of thermal radiation. Reflective insulations are mainly used in combination with the non-ventilated air cavity. Proposed paper deals with experimental measurements of the thermal insulation properties of the air cavity surrounded by low-emissivity surfaces and comparison of measured values with calculated values according to the standardized procedures. The beginning for determination of the thermal resistance of air cavity was to conduct several experimental measurements by Hot Box method using heat flow meter. The results show good agreement between measured and calculated data.

Layered composite thermal insulation system for nonvacuum cryogenic applications

A problem common to both space launch applications and cryogenic propulsion test facilities is providing suitable thermal insulation for complex cryogenic piping, tanks, and components that cannot be vacuum-jacketed or otherwise be broad-area-covered. To meet such requirements and provide a practical solution to the problem, a layered composite insulation system has been developed for nonvacuum applications and extreme environmental exposure conditions. Layered composite insulation system for extreme conditions (or LCX) is particularly suited for complex piping or tank systems that are difficult or practically impossible to insulate by conventional means. Consisting of several functional layers, the aerogel blanket-based system can be tailored to specific thermal and mechanical performance requirements. The operational principle of the system is layer-pairs working in combination. Each layer pair is comprised of a primary insulation layer and a compressible radiant barrier layer. Vacuum-jacketed piping systems, whether part of the ground equipment or the flight vehicle, typically include numerous terminations, disconnects, umbilical connections, or branches that must be insulated by nonvacuum means. Broad-area insulation systems, such as spray foam or rigid foam panels, are often the lightweight materials of choice for vehicle tanks, but the plumbing elements, feedthroughs, appurtenances, and structural supports all create “hot spot” areas that are not readily insulated by similar means. Finally, the design layouts of valve control skids used for launch pads and test stands can be nearly impossible to insulate because of their complexity and high density of components and instrumentation. Primary requirements for such nonvacuum thermal insulation systems include the combination of harsh conditions, including full weather exposure, vibration, and structural loads. Further requirements include reliability and the right level of system breathability for thermal cycling. The LCX system is suitable for temperatures from approximately 4K to 400K and can be designed to insulate liquid hydrogen, liquid nitrogen, liquid oxygen, or liquid methane equipment. Laboratory test data for thermal and mechanical performance are presented. Field demonstration cases and examples in operational cryogenic systems are also given.

Reducing Energy Consumption through Innovative Glass Layering Construction with Polyethylene Bubble Wrap at 2<sup>nd</sup> Floor Dean Faculty Room

Reducing energy consumption in buildings has been an important and growing concern in most countries since the Kyoto Protocol was entered into force in 2005. For instance, ITS has set the target reduction of greenhouse gases in building and support act as a legal framework for promoting ECO Campus program. Design concept using glass layering construction with bubble wrap can contribute significantly in reducing the required air conditioning system size so annual energy cost decrease too. The objective of this paper is to present an overview of the basic principles of thermal insulation, the example of building energy modeling using polyethylene insulation materials, and to survey the most commonly used building insulation materials as well as their performance characteristics. A “bubble wrap” with a reflective insulation helps to reduce heat loss by reflecting away up to 97% radiant energy with less than 0.05 emittance. The result from this study is 3% to 6% annual energy savings was cited.

원전 금속단열재의 구조 건전성 강화를 위한 설계 방안

The goal of this paper is to investigate structural integrity factors of RMI(reflective metal insulation) to confirm the design requirements in nuclear power plant. Currently, a glass wool insulation is using now, but it will gradually be replaced with the reflective metal insulation maded by stainless steel plates. The main function of an insulation is to minimize a heat loss of vessel and pipes in RCS(reactor coolant system). It has to maintain structural a integrity in nuclear power plant life duration. In this study, the structural integrity analysis was carried out both multi-plate and outer shell plate by using a static analysis and experimental test. First, inner multi-plate has a self support structure for being air space. Because the effect of total static weight in multi-layer plate is low, a plate collapse possibility is not high. Considering optimum thin plate pressing process, it has to pre-check the basic physical properties. Second, the outer segment thickness and stiffener shape are verified by the numerical static analysis, and sample test for both type of panel and cylindrical pipe model.

Development for cool roof calculator for India

In tropical countries such as India, increasing the roof albedo helps to reduce the heat ingress through the roof. This further reduces air-conditioning energy consumption in conditioned buildings and increases comfort in unconditioned buildings. In order to help users determine the benefits of high albedo roofs under varying conditions, a simple calculator has been developed. Parameters such as location, building type, roof area, and surface properties of the roof are taken as inputs. Annual EnergyPlus simulations are performed for the given parameters and the results are displayed in both graphical and tabular formats. It also calculates the simple payback by comparing a given base case roof albedo with the proposed roof albedo. The calculator can perform comfort simulations for unconditioned buildings and simulates measures including a radiant barrier system and under deck roof insulation. The calculator also runs a parametric simulation between insulation thickness and roof albedo to find an optimum roof insulation thickness based on incremental internal rate of return. This paper presents the features of the cool roof calculator and the type of analysis that can be performed using the cached results.

Comparison of software models for energy savings from cool roofs

A web-based Roof Savings Calculator (RSC) has been deployed for the United States Department of Energy as an industry-consensus tool to help building owners, manufacturers, distributors, contractors and researchers easily run complex roof and attic simulations. RSC simulates multiple roof and attic technologies for side-by-side comparison including reflective roofs, different roof slopes, above sheathing ventilation, radiant barriers, low-emittance roof surfaces, duct location, duct leakage rates, multiple substrate types, and insulation levels. Annual simulations of hour-by-hour, whole-building performance are used to provide estimated annual energy and cost savings from reduced HVAC use.While RSC reported similar cooling savings to other simulation engines, heating penalty varied significantly. RSC results show reduced cool roofing cost-effectiveness, thus mitigating expected economic incentives for this countermeasure to the urban heat island effect. This paper consolidates comparison of RSC's projected energy savings to other simulation engines including DOE-2.1E, AtticSim, Micropas, and EnergyPlus. Also included are comparisons to previous simulation-based studies, analysis of RSC cooling savings and heating penalties, the role of radiative heat exchange in an attic assembly, and changes made for increased accuracy of the duct model. Radiant heat transfer and duct interaction not previously modeled is considered a major contributor to heating penalties.

The Preparation of Fluorocarbon Thermal Insulation Coating with Different Fillers

According to the mechanism of thermal insulation, closed pore perlite, hollow glass microsphere and nanoantimony tin oxide (ATO) powder three different kinds of functional fillers were adopted respectively to prepare obstructive, reflective and radiative thermal insulation coating base on polyvinylidene fluoride emulsion, and how the category and content of functional fillers effect the thermal insulation performance of the fluorocarbon thermal insulation coating (FTIC) was investigate. The test results showed that, all the three functional fillers has an significant effect on the thermal insulation performance of FTIC.

Optimizing roof insulation for roofs with high albedo coating and radiant barriers in India

To make roofs energy efficient, typically two types of techniques are followed: surface treatments (cool roofs, radiant barriers) and thermal property modifications (roof insulation). The interplay between these two techniques has been studied using energy simulations. A single storey, daytime operational, office building of 200m2 area has been simulated for five climatic zones in India. A total of 88 different roof combinations have been studied for each climatic zone. An economic analysis using Internal Rate of Return has been performed to identify a suitable roof insulation thickness for a roof with high albedo, and radiant barrier combination. The incremental benefits in energy savings reduces by adding insulation after a limit. For a roof with albedo of 0.6 and radiant barrier emittance of 0.2, the optimized roof R-value is 0.49m2K/W in hot and dry and composite climates, 0.31m2K/W in warm and humid and temperate climates, and 1.02m2K/W for cold climates.

Evaluation Method for Energy Saving Effect of Reflective Thermal Insulation Coatings

According to the climate and energy saving characteristics in the hot summer and cold winter zone, especially in view of requirements for thermal insulation in summer, reflective thermal insulation coatings (RTIc) are gradually applied in building energy efficiency of exterior envelope. A feasible evaluation method for energy saving effect is very important for acceptance of energy efficient building construction. In this paper, thermal resistance has been used as the evaluation index. The energy efficiency of the reflective thermal insulation coatings was investigated. Four hot boxes were applied contrast test. Based on the qualitative and quantitative analysis of electricity consumption within 36 hours and comparative analysis of heating process simulating sunlight environment, thermal resistance of RTIc can be calculated on the basis of the correlation between power saving rate and thermal resistance so that energy saving effect of RTIc can be quantitatively characterized.

Numerical analysis of hygrothermal performance of reflective insulated roof coatings

The use of thermal insulation in roofing systems has been progressively increased in the last few years especially in emerging market countries to reduce energy consumption due to the more frequent use of air conditioners. However, moisture can meaningfully affect the performance of the roof and cause deterioration of the insulation as well as increasing the risk of mold growth. Therefore, for the prediction of performance and risks in roofing systems, a fully combined heat and mass transport model through roofing systems used in hot and humid climates is needed as it is barely explored in the literature. In this way, a mathematical model considering the combined two-dimensional heat, air and moisture transport through unsaturated roofing systems is presented in this paper. In the porous domain, the differential governing equations are based on driving potentials of temperature, moist air pressure and water vapor pressure gradients, while, in the air domain, a lumped approach is considered for modeling the heat and mass transfer through the cavity between the roof sheet and insulation. Results are presented in terms of heat flux and temperature and moisture content distributions profiles within the porous roofing structure, indicating the impact of moisture adsorption and desorption on the roofing hygrothermal performance due to additional transport mechanisms. The paper shows the importance of using a more complete mathematical model – even when conductive latent loads are negligible due to an impermeable reflective insulation – since the mass transport and phase change mechanisms modify the temperature distribution, which cannot be observed by purely conductive heat transfer models presently used in most building energy simulation tools. The roofing short and long-wave radiation heat transfer processes, including the multi-reflective effect of aluminum foil in the air cavity, are also presented and discussed.

Standardization in Cryogenic Insulation Systems Testing and Performance Data

The close relationship between industrial energy use and cryogenics drives the need for optimized thermal insulation systems. Emerging cryofuels usage is enabled by adequate isolation of the liquid hydrogen or liquefied natural gas from the ambient environment. Thermal performance data for the total insulation system, as rendered, are essential for both engineering designs and cost-benefit decisions involving comparisons among alternatives. These data are obtained through rigorous testing with suitable apparatus and repeatable methods. Properly defined terminology, analysis, and reporting are also vital. Advances in cryogenic insulation test apparatus and methods have led to the recent addition of two new technical standards of ASTM International: C1774 - Standard Guide for Thermal Performance Testing of Cryogenic InsulationSystems and C740 - Standard Guide for Evacuated Reflective Cryogenic Insulation. Among the different techniques described in the new standards is the cylindrical boiloff calorimeter for absolute heat measurement over the full range of vacuum pressure conditions. The details of this apparatus, test method, and data analysis are given. Benchmark thermal performance data, including effective thermal conductivity (ke) and heat flux (q) for the boundary temperatures of 293K and 77K, are given for a number of different multilayer insulation (MLI) systems in comparison with data for other commonly-used insulation systems including perlite powder, fiberglass, polyurethane foam, and aerogels.

Protecting trapped animals from heat exposure: the influence of shading on temperature within small metal box traps

Animal research guidelines recognise that trapped animals can potentially be subjected to heat stress, but recommendations are limited to avoiding exposing traps to weather extremes. Intuitively, shading metal box traps should be beneficial in warm to hot climates. Temperatures inside metal box traps were measured within traps located in direct sunlight concurrently with ones covered with artificial shading. Additionally, comparisons were conducted in continuous shade cast by ground-cover vegetation, and in stippled sunlight under an artificial lattice. Deep continuous shade from vegetation was most effective and able to keep traps within 5°C of ambient. Artificial shading using dark shade cloth could actually elevate trap temperatures above that in uncovered traps when exposed to direct sunshine. Reflective foil insulation cover not only provided rain protection for traps but was the most effective shading method trialled for reducing both the rate at which traps heated after sunrise and the maximum temperature reached during the day when exposed to direct sunshine. The use of foil sleeves can provide an extra level of protection from excessive heat exposure to trapped animals, keeping trap temperatures as much as 15°C lower than unprotected traps.

Preparation and characterization of a reflective and heat insulative coating based on geopolymers

A reflective heat insulation coating was prepared using a geopolymer, which was mainly made of sodium silicate solutions and metakaolin, as the primary film forming material before adding sericite powder, talcum powder, titanium dioxide and hollow glass microspheres as fillers. This coating is a new, environmentally friendly inorganic coating with many capabilities, such as good water-retention, simple spraying, the compacted paint, high durability, dirt resistance, high reflectivity and remarkable heat insulation. The results indicate a titanium dioxide content of approximately 12% yields 6% hollow glass microspheres yielded a reflective heat insulation coating with a reflectivity over 90% and thermal insulation performance (internal and external surface temperature difference) of up to 24°C. These mechanical and insulative properties could achieve the China National Standard (GB/T25261-2010).

Evaluation of the Thermal Resistance of Structure with Reflective Insulation: Measurement under Non-Stationary Boundary Conditions

Some manufacturers of reflective insulation products claim that their relatively thin products have the same thermal insulation properties as common insulation with much times higher thickness. This paper deals with experimental measurements of the thermal insulation properties of real structures with reflective insulation. Several experimental sequences were conducted to determine the thermal resistance of the structure. The evaluation was conducted according to the procedures specified in the international standard (ISO 9869 - 1994). Effect of products (based on the reflection of thermal radiation) on the thermal insulation properties of the structure will be determined by evaluation. This effect will be compared with the effects of common insulation (with the intention of reduce of the heat transfer by the conduction).

Influence of Reflective Insulation Coating on Heat Transfer Characteristics of Composite Thermal Insulation Wall

In the downstream of Yangtze River where there is abundant silt resources, perforated brick which fired by sludge, supplemented by reflective insulation coating to replace the widely used polystyrene insulation materials. It can achieve requirement of A-class fire prevention for heat preservation wall. The heat insulation performance of not painted thermal wall and composite thermal insulation wall painted by reflective insulation coating were compared. Data results show that heat insulation performance of the wall painted is much better than that of the not painted wall.