[China Glass Network] 1. Introduction China is a major energy consumer, and building energy consumption, industrial energy consumption and transportation energy consumption are the main sources of energy consumption. According to statistics: building energy consumption accounts for about 30% of total energy consumption, which may reach 35% in the next 20 years; in building energy consumption, energy consumption lost through glass doors and windows accounts for all building energy consumption. 2/3, where the heat transfer loss is 1/3. The relevant data shows that the energy lost through the glass accounts for 80% of the energy loss of the door and window. Therefore, improving the energy-saving performance of glass has become the key to realizing building energy efficiency. 2, several terms 2.1, solar spectrum The wavelength of energy radiated by the sun ranges from about 0.15 μm to 4 μm, and concentrates about 97% of the energy in the wavelength range of 0.3 μm to 2.5 μm. The ultraviolet wavelength range is from 280 nm to 380 nm, and its radiant energy accounts for about the total solar radiant energy. 7%; visible light wavelength range is 380nm ~ 780nm, accounting for about 50% of total solar radiation energy; near-infrared light wavelength range is 780nm ~ 2500nm, accounting for about 43% of total solar radiation energy. Only visible light has an effect on building lighting. 2.2, visible light transmittance Tvis The visible light transmittance is a percentage of the ratio of the light intensity of the transmitted glass to the incident light intensity in the visible spectrum (380 nm to 780 nm). Under the condition of maintaining the same low radiation performance, the higher the visible light transmittance of the glass, the better the indoor lighting effect, but the solar heat entering the room will increase accordingly. 2.3, glass shielding coefficient SC According to the standard GB/T2680-94 "visible glass transmittance, direct sunlight transmittance, total solar transmittance, ultraviolet transmittance and the measurement of window glass parameters", the shielding coefficient is defined as: under normal incidence conditions, The ratio of the total solar energy transmittance of the light transmission system to the total solar energy transmittance of standard glass (3 mm thick ordinary transparent flat glass) of the same condition and the same area. The shielding factor of the glazing indicates the degree of attenuation of the heat transmitted by the solar radiation in the absence of other shading measures. 2.4, heat transfer coefficient K The heat transfer coefficient K is an important indicator to measure the thermal insulation performance of glass. It is also called U value in Europe and America. The heat transfer coefficient is the heat transfer amount per unit time through the 1 m2 hollow glass under the condition of stable heat transfer, when the temperature difference between the air on both sides of the glass is 1 ° C, expressed in units of W/(m 2 ·K). The lower the heat transfer coefficient K value, the better the thermal insulation performance of the glass, the less the heat loss, and the more significant the energy saving effect in use. 3. Comparative analysis Insulating glass is an article in which air or an inert gas (such as argon (indicated by A), helium) is sandwiched between two or more sheets of glass, and is evenly spaced and bonded by an effective support. The insulating glass mainly reduces the heat transfer coefficient through the middle gas layer, thereby achieving the effect of heat preservation and energy saving. The commonly used hollow glass has a thickness of 3 mm, 4 mm, 5 mm, 6 mm, 10 mm, 12 mm, etc., and the intermediate gas layer has a thickness of 6 mm, 9 to 12 mm, and 12 to 20 mm. We know that heat loss is achieved by conduction, convection and heat radiation. The currently used insulating glass can effectively prevent the conduction and convection of heat, and play a certain role in energy saving and heat preservation. By using a Lambda950 UV/Vis/NIR spectrophotometer and a Fourier transform infrared spectrometer, ordinary single-piece transparent glass, transparent insulating glass and low-emission (Low-E) coated insulating glass were respectively analyzed by comparing visible light transmittance, The parameters such as the shielding factor are used to analyze the energy-saving performance of the three glasses. 3.1. Energy-saving detection and comparative analysis of ordinary single-piece transparent glass and transparent insulating glass For 6mm ordinary single-chip white glass and 6mm+12Amm+6mm hollow glass, the spectrophotometer and infrared spectrometer are used to test in the wavelength range of 280 nm to 2500 nm of solar spectrum. The obtained parameters are shown in Fig. 1 and Fig. 2. It can be seen from Fig. 1 that the visible light transmittance Tvis of 6 mm ordinary white glass is 0.8797, which is about 88.0%; the value of the shielding coefficient SC is 0.955; the heat transfer coefficient U value (ie, K value) is 5.816; and the visible light reflectance is 8.24. %; direct sunlight transmittance is 79.2%. It can be seen from Fig. 2 that two ordinary white glass with a thickness of 6 mm and a argon gas of 12 mm are sandwiched therebetween, and the visible light transmittance Tvis of the hollow glass is 0.7663, that is, 76.6%; the value of the shielding coefficient SC is 0.815; heat transfer The coefficient U value (i.e., K value) was 2.538; the visible light reflectance was 14.6%; and the direct sunlight transmittance was 62.6%. Compared with ordinary white glass, hollow glass has a thermal conductivity lower than that of glass due to the air or inert gas between two or more sheets of glass, thereby increasing the thermal resistance and reducing the heat transfer coefficient. It can be seen from Fig. 1 and Fig. 2 that the heat transfer coefficient is reduced from 5.816 to 2.538, and the heat transfer coefficient of the insulating glass is only 44% of the single-layer glass, which achieves effective blocking of heat conduction and convection, and obtains good thermal insulation. effect. However, ordinary insulating glass has a high heat radiation and does not have a good effect on the prevention of radiation. It can be seen from Fig. 2 that the shielding coefficient of ordinary insulating glass is as high as 0.815, and the effect on building energy-saving and heat insulation is not prominent. 3.2. Low-Emission (Low-E) coated hollow glass energy-saving detection and analysis The 6mmLow-E+12Amm+6mm hollow glass was tested in the wavelength range of 280 nm to 2500 nm in the solar spectrum using a spectrophotometer and an infrared spectrometer. The obtained parameters are shown in Fig. 3. It can be seen from Fig. 3 that a piece of Low-E glass with a thickness of 6 mm and a piece of ordinary white glass of 6 mm are sandwiched with 12 mm of argon gas, and the obtained visible light transmittance Tvis of the insulating glass is 0.5043, that is, 50.4%; the shielding coefficient SC is The value is 0.548; the heat transfer coefficient U value (ie, K value) is 1.842; the visible light reflectance is 23.2%; the direct sunlight transmittance is 31.0%, which belongs to the sunshade Low-E glass. Compared with ordinary insulating glass, the heat transfer coefficient U value is reduced from 2.538 to 1.842, and a better thermal insulation effect is obtained. The shielding coefficient SC is reduced from 0.815 to 0.548, which effectively prevents solar heat radiation from entering the room, thereby reducing heat loss and exerting the effect of building energy saving. In addition, compared with ordinary insulating glass, the solar reflectance of Low-E insulating glass is increased from 12.9% to 22.9%. Therefore, Low-E glass has a strong reflection effect on long-wave radiation. 4 Conclusion (1) Compared with ordinary white glass, ordinary insulating glass can more effectively achieve the barrier of heat conduction and convection, and obtain good thermal insulation effect. However, its shielding coefficient is relatively high, and the effect on building energy-saving and heat insulation is not very prominent. (2) Low-emission (Low-E) coated hollow glass has better thermal insulation effect than ordinary insulating glass. Moreover, the shielding coefficient is reduced, the solar light reflectance is increased, and the solar heat radiation is effectively prevented from entering the room, thereby reducing heat loss and exerting the effect of building energy conservation. (3) Fully understanding the existing energy-saving glass products, and constantly researching and developing new glass with superior performance is of great significance to the energy conservation of building energy consumption. Smart Casual Shoes,Woodland Casual Shoes,Sparx Casual Shoes,Mens Casual Slip On Shoes Huaying Shoes Co. Ltd , https://www.hyashoes.com