Application Status of Building Energy – saving Glass
Glass insulation principle
The glass can transfer heat, there are two ways, one is the glass transparent nature can combine the solar energy incident with temperature field high temperature zone, to achieve high temperature to low temperature heat radiation conversion; The other way is taking glass as a main material of exterior protected construction, to form a heat flow through the material thermal conductivity. Thus, during the glass processing and manufacturing process, in order to achieve the better insulation, heat insulation, energy saving effect, the glass heat transfer coefficient U and shielding coefficient Se value need be reduced.
Comparison of current building energy saving glass types
Hollow and vacuum glass
Hollow glass is to use 2 ~ 3 layers of glass or laminated glass, each layer of the glass can be evenly divided, there is a lot of inert gas or air drying in the interval cavity, heat transfer coefficient was created in the middle of the gas layer. The conventional hollow glass shading coefficient is high, the insulation effect is not very good, mainly used in the northern cold area as the insulation material. Empty the middle of the plate glass, forming a vacuum layer which can block the heat conduction and convection, as a result, the heat transfer coefficient is much lower than that of hollow glass, thermal insulation performance is superior, and the cost is 4 ~ 6 times of hollow glass.
1.2.2 Heat reflective glass
The surface of this glass has one or more layers of metal oxide film, with a strong reflectivity and light transmission. Shading coefficient is small, and the visible light rate is low, thus it will have an impact on indoor lighting in the future use. There is no big difference in the heat transfer coefficient compared with ordinary glass. The insulation effectis not strong.
1.3Low ~ E glass
Low ~ E glass is a low-emissivity glass, the surface of this glass has a layer or multi-layer metal semiconductor film, near-infrared radiation reflectivity is low, while the far-infrared radiation is higher, with good light transmission and energy saving effect , Low ~ E glass is mainly used in the manufacture of composite insulating glass, the price is higher than conventional glass.
2 Aerogel Insulation Blanket Transparent Insulation Material Building Energy Saving Glass Application
2.1 Aerogel
Aerogel is a kind of three-dimensional network structure composed of colloidal particles or highly polymerized molecules, which is a typical lightweight nano-porous material. In view of the translucent color with lighter weight, also known as “solid smoke”. NASA has developed a new type of aerogel, the density is 2.45kg / m3, which is the world’s lowest density solids.
2.2 The thermal insulation mechanism of aerogel
The thermal conductivity of superinsulation material is lower than that of convective air thermal conductivity. There are two main types, one is vacuum insulation, one is nano-porous insulation material.The former is more difficult to maintain a high vacuum, the latter can reach 70% ~ 88.5%, the gap size is < 40nm, and the size of the network colloid particle is 2-25nm. The thermal infrared radiation in the area of 2 ~ 6um, has a high shielding efficiency because of its shielding function, and the porous grid structure of hea insulation effect. Aerogel thermal conductivity is 0.02 ~ 0.04w / (m • K) at room temperature. Silica aerogels have a very high use temperature limit, it can also have a porous mesh structure at 800 ℃ high temperature , and will not be deformed or burned, with a strong fire function. Thus aerogels can be widely used in energy efficiency buildings because of Thermal insulation materials properties, light transmission performance, noise and heat insulation effect. In the application of granular gel, a new type of silica aerogel transparent glass was developed. Using methyl methacrylate film as aerogel and krypton gas was added to the glass, the total solar transmittance was 38%.
Source: http://www.aerogelinsulationblanket.com/product-news/aerogel-industry-development.html
