High Heat Insulation Research Articles

Thermal insulation material based on SiO2 aerogel

SiO2 aerogel is a solid material with three-dimensional network structure, has a very low density and low thermal conductivity, can be used as a kind of high efficient heat preservation and heat insulation material, as well as SiO2 aerogel particles. In this work, we have successfully prepared a mortar with SiO2 aerogel particles. Density, mechanical properties, softening coefficient, autogenous shrinkage, antifreeze performance and thermal conductivity properties were studied when the SiO2 aerogel particles replacement ratio was 10%, 20%, 30%, 40%, 50% and 60%. The mortar based on SiO2 aerogel particles shows a density of ∼1.2g/cm3, a compressive strength and flexural tensile strength of ∼2.15MPa and ∼0.45MPa, a thermal conductivity of ∼0.1524W/m·K at the aerogel content of 60vol.%. And on this basis, the thermal conductivity was focused on study when fiber, air-entraining agent and powder were added into the mortar. The results show that when the dosage was 0.2%, 0.05% and 1% respectively, the thermal conductivity was the lowest (0.0859W/m·K).

PRODUCTION OF AN INSULATION MATERIAL FROM CARPET AND BORON WASTES

Buildings are large consumers of energy in all countries. In regions with harsh climatic conditions, a substantial share of energy goes to heat and cool buildings. This paper reports an investigation of the insulation materials made from mixing carpet wastes with a solution with added crude colemanite ore, one of boron minerals, and a solution with added colemanite wastes from a barrage. A new building insulation material was produced which is name, Halibor. Optimum mixing ratios were determined for mass production and the physical properties of the product were established. In addition, the material produced was compared with similar products used in buildings in terms of physical properties. As a result of the investigations, it was established that the product provides high heat and sound insulation and can be used easily in building and construction industry.

Impact of External Heat Insulation on Drying Process of Autoclaved Aerated Concrete Masonry Constructions

In the time when sustainable construction as well as cost saving on heating and cooling of buildings is one of the most important construction trends, it is important to acknowledge the possibilities of application of construction materials with high heat insulation parameters and the ways in which these parameters can be obtained. Autoclaved aerated concrete (AAC) is a load bearing construction material, which has high heat insulation parameters, although it has one significant disadvantage. If the AAC masonry construction has high moisture content, it loses its heat insulation properties. This is the reason why it is important to detect the humidity distribution throughout the cross section of the masonry elements in order to conduct the drying process of the AAC construction. Therefore, the question about non-destructive detection of humidity distribution throughout the cross section of the material arises. Humidity distribution throughout the cross section of AAC masonry constructions has a significant impact on its heat resistivity properties. Application of electrical impedance spectrometry (EIS) method for determination of humidity distribution throughout the cross section of AAC constructions has been a subject of research recently. The EIS method is an easily applicable non-destructive testing method for detection of the humidity distribution throughout the cross section of a construction. Research on the impact of the external heat insulation layer on the speed of humidity distribution changes is described in this paper.

Optimal Operation of ERV System Installed in the Apartment Houses in South Korea

High air-tightness and high heat-insulation of buildings cause lack of fresh air inside the buildings. Operating the ventilation system in an apartment house may improve the indoor air quality, but may generate the problems, such as high airconditioning load and cold draft. In order to improve the indoor air quality while maintaining pleasant heat environment to a certain level, it is necessary to consume energy for cooling and heating. Energy Recovery Ventilation system (here in after “ERVs”) is the typical way to minimize the consumption of energy. To solve the problem, the installation of ERVs has been made mandatory for new apartment buildings that are constructed in the Republic of Korea. The interest in ERVs has increased recently in that the System is viewed as helping to: 1. Reduce energy costs of heating and cooling apartment buildings, which costs claim a significant portion of apartment building management budgets, and 2. Secure appropriate levels of ventilation in such buildings. Despite the enthusiasm, the lack of efficient implementation of ERVs persists. Based on the rationale, this study realized the optimal operating algorithm for ERVs. The study took actual data on temperature and humidity; operation status on air conditioners and ERVs; electricity consumptions; and PMV. The study analyzed airconditioning ventilation loads and energy-saving effects related thereto according to the optimal operating algorithm for ERVs. The results showed statistically significant figures that contribute to the reduction of loads and energy costs. Implications of the study include: 1. Introducing the optimal ERVs to apartment buildings will likely help the residents and building managers to better respond to changes occurring to the outside environment and to the inside loads being applied to indoor HVAC systems; and 2. Implementation of ERVs would likely help reduce the loads being imposed on the HVAC systems in apartment buildings.

Impact of density and special features of manufacturing process on drying of autoclaved aerated concrete masonry blocks

Autoclaved aerated concrete (AAC) masonry blocks are construction material with high heat insulation parameters. In time of sustainable construction, this material can be used as a load bearing construction material for a range of buildings where it is necessary to obtain high heat insulation parameters of external delimiting constructions. The main problem of autoclaved aerated masonry constructions is the significant influence of relative humidity rate and its gradient on heat resistivity properties of the masonry constructions. Therefore it is important to monitor the drying process of AAC masonry constructions in order to avoid the sealing of moisture inside the masonry by early application of finishing layers on the construction. As there is a variety of manufacturers who offer AAC masonry blocks and the manufacturing process of the blocks slightly differ as well as the ingredients used for the manufacturing of the blocks this research has been done to determine the impact of manufacturing features and density of the blocks on their drying properties. The testing has been performed by non-destructive testing method – electrical impedance spectrometry (EIS) In the paper, there are included results of research of correlation between EIS and moisture content rate in masonry blocks provided by different manufacturers. All used blocks are with similar material density. As a result of the research correlation formulas between saturation rate of the material and EIS measurement result have been established and a graph of humidity migration throughout the cross section of the masonry construction has been determined.

Synthesis of boron nitride nanotubes and their applications

Boron nitride nanotubes (BNNTs) have been increasingly investigated for use in a wide range of applications due to their unique physicochemical properties including high hydrophobicity, heat and electrical insulation, resistance to oxidation, and hydrogen storage capacity. They are also valued for their possible medical and biomedical applications including drug delivery, use in biomaterials, and neutron capture therapy. In this review, BNNT synthesis methods and the surface modification strategies are first discussed, and then their toxicity and application studies are summarized. Finally, a perspective for the future use of these novel materials is discussed.

환기시스템을 갖춘 온돌 성능에 관한 연구

Modern apartment houses are constructed to be relatively airtight with a high heat insulation system to increase the energy efficiency. Such a system has a range of deleterious effects due to the insufficient ventilation. In this study, the ondol system, which is used as a heat source typical of winter in Korea, was set as the default system to evaluate the indoor heat environment according to the ventilation method, the factors of energy reduction by the ventilation system was analyzed. The experimental apparatus was used to simulate the ambient conditions for a certain constant temperature and humidity chamber. The experimental results showed that the supply water temperature higher air volume decreases with increasing supply air temperature in the following order: floor supply/exhaust > total heat exchange supply/exhaust > forced supply/exhaust. Through this study, the applicability of various ventilations could be examined.

高耐熱絶縁電着塗料の塗膜形成制御技術

高耐熱絶縁電着塗料の塗膜形成制御技術

Preparation of Al2O3–ZrO2 nanocomposite films by laser chemical vapour deposition

Alumina (Al2O3)–zirconia (ZrO2) nanocomposite films were prepared by laser chemical vapour deposition. α-Al2O3–ZrO2 and γ-Al2O3–t-ZrO2 nanocomposite films were prepared at 1207 and 1000 K, respectively. In the nanocomposite films, 10-nm-wide t-ZrO2 nanodendrites grew inside the α- or γ-Al2O3 columnar grains. The γ-Al2O3–t-ZrO2 nanocomposite films exhibited high nanoindentation hardness (28.0 GPa) and heat insulation efficiency (4788 J s−1/2 m−2 K−1).

Gasket for refrigerator cabinets with high heat insulation properties

Gasket for refrigerator cabinets with high heat insulation properties

Technical Note: The Contribution of Perlite to the Sound Transmission Loss of Solid Masonry Walls

The sound insulation of solid masonry walls can be improved either by plastering or by changing the constituent materials of the wall blocks. Whilst traditional cement-lime-sand plasters are still in use, plasters containing perlite are preferred, especially in cold climates, due to their high heat insulation characteristics. In this study the contribution of perlite to the sound transmission loss of solid walls is investigated. Two series of measurements were conducted in the laboratory. In the first, perlite was added to the in-laboratory prepared plasters, and in the second perlite was included as an additional constituent to the mixture when casting gypsum blocks. The mean transmission loss of the brick wall was increased by approximately 19 dB when plastered on both sides by plaster containing perlite. When perlite was a constituent of the gypsum wall blocks the average transmission loss was increased by approximately 1 dB.

Analysis of IN-SITU Converted Chrysotile Asbestos Fibers in Sprayed on Fireproofing

A BNL-Grace process has been developed to chemically convert in-situ, the chrysotile fibers of sprayed-on fireproofing products to an unregulated glassy material. The effectiveness of this process has been convincingly demonstrated using Analytical Electron Microscopy and X-Ray Diffraction techniques.Asbestos minerals were used in fireproofing materials because of their excellent physical properties including fire resistance, high tensile strength, heat and electrical insulation, and resistance to acids and alkali. But in 1975 the Environmental Protection Agency began regulating materials containing > 1% asbestos.The new in-situ BNL-Grace process, which uses a foamy solution sprayed directly onto asbestos-containing fireproofing chemically digests essentially all the asbestos fibers, transforming them into harmless materials. After treatment, the fireproofing is no longer a regulated material. The process produces essentially no waste.Our problem was to demonstrate that all of the asbestos was converted and that the remaining materials were no longer regulated. Typical analysis methods use conventional optical and Polarized Light Microscopy (PLM) to measure and observe fibers.

Ein kalorimeter für hochenergetische elektronenstrahlen

Construction details and experimental data are given for a total absorption calorimeter used for electron beams of several hundred MeV and for beam power up to 15 kW. In order to obtain high precision, precautions were taken to obtain very high heat insulation, specially by using a temperature controlled radiation shield. The heat loss of the 700 kg copper block corresponds to less than 10 −3 °C/h. Due to design calculations and confirmed by preliminary comparison tests with other beam monitors we consider the absolute accuracy to be 1% or probably better.