Two key elements of energy-saving windows: window type and energy-saving glass

China's door and window industry is developing along with the rapid economic development. With the continuous development of new materials, the doors and windows industry will develop to high-end, new, multi-functional, multi-variety, and many truly energy-saving types. ICESUN vacuum glass seized this important opportunity in history to develop truly energy saving vacuum glass for doors and windows.

Correctly understand the "energy-saving window"

The energy-saving window is the development direction of our industry. How to recognize the energy-saving window and how to count it as energy-saving must be understood from the three elements of thermodynamic heat conduction: the loss of thermodynamic heat (exchange of heat) and convection, conduction and radiation of heat. Convection is the circulation of hot and cold air flow between the gaps of doors and windows, which causes the convection of gases to drive heat exchange, and the convection of hot and cold air causes the loss of heat. Heat conduction is the transfer of heat by the molecular movement of the material itself. Heat conduction is transferred from one surface of the object to the other. Radiative heat transfer is the direct transmission of energy by rays, ie infrared rays. Regardless of the materials used to make the window, if it can be the most effective blocking and control of the above three kinds of heat exchange, it can be called the best energy-saving window.

Analysis of Two Key Elements of Energy Saving Window

In order to better achieve the blocking of the three kinds of heat exchange and achieve a real energy saving window, we must consider from the following aspects:

Window type is the first element of energy-saving window

Sliding windows are not energy-saving windows. Casement windows and fixed windows are energy-saving windows. First of all, considering the structural design of the window, the structure of the window plays a major role in energy saving. If the sliding window slides back and forth on the sliding rails of the window frame, there will be more space on it, and there will be gaps between the pulleys. The window fans will form a clear convection exchange between them. Convection of hot and cold air will cause large heat loss, convection size, and heat. The size of the loss is proportional to the space above and below the sash. What thermal insulation profiles are used for window frames at this time does not achieve the energy-saving effect. It can be said that whether sliding windows made of aluminum alloy or steel are not qualified as energy-saving windows.

The casement windows, sashes and window frames are generally well-used with good rubber seals. After the window sashes are closed, the sealing rubber battens are pressed tightly. There is almost no gap and it is difficult to form convection. The heat loss of this type of window is mainly glass, sashes and window frame profiles, heat conduction and radiation heat dissipation, this heat dissipation is much less than the convection heat loss, if you can well solve the heat conduction of the above glass and window frame profiles, flat The energy-saving effect of window-opening has obvious advantages over the energy-saving effect of sliding windows. Casement windows can be called “energy-saving windows”.

The fixed window and window frame are embedded in the wall. The glass is directly mounted on the window frame. The glass and window frame are now sealed with a sealant instead of a rubber strip. The four sides of the seal are sealed. If the sealant is tightly sealed, air is difficult to pass through. Sealant forms convection and it is difficult to cause heat loss. The heat conduction of the glass and window frame of the fixed window is the source of the main heat loss. Taking effective measures on the glass can greatly improve the energy saving effect. Structurally, the fixed window is the most energy-efficient window type. In order to ventilate the ventilation, a small upturn-down window is installed on the fixed window, or a small window is fixed on one side of the fixed window, which is specially used as a timing air release.

There are still window tops, various sliding windows up and down, and various types of window types such as outside and inside, but they are all changed within the three types of window types: push, pull, and open.

Glass is the second element of the energy-saving window

In addition to the window structure, the window's maximum thermal and radiation area is glass. The main heat dissipation of glass is by heat conduction and heat radiation. Conduction is the transfer of heat from the inner surface of the glass through the molecular motion of the glass to the outer surface of the glass window. The size of the heat conduction and the conduction velocity, the thickness of the glass, and the thermal conductivity of different glasses are related, and at the same time they are related to the properties of the glass of different properties, and the radiation is related to the glass of different properties.

1. Heat reflective coated glass

It has good controllability to optics, and has good reflection and absorption ability for the wavelength of 0.3-2.5mm of sunlight. It can significantly reduce the transmission of sunlight's radiant energy to the room, maintain a stable indoor temperature, and save energy.

Under normal circumstances, heat-reflective coated glass has been able to meet the needs of general energy-saving windows, such as higher requirements, hollow glass and heat reflective coating hollow glass and low-emissivity coated glass, but all have their own characteristics and different uses.

2. Insulating glass

Hollow glass not only has excellent lighting performance, but also has special advantages such as heat insulation, sound insulation, and anti-frost. Hollow glass has excellent thermal insulation properties, and under certain conditions, its thermal insulation performance is superior to that of general concrete walls. Insulating glass insulation is mainly derived from the air layer sealed between the two layers of glass. The thermal conductivity of this air is 0.028W/MK, and the thermal conductivity of the glass is 0.77W/MK. The sealed insulating glass is thermally conducted on the four sides of the glass with the sealant. The rest of the large area of the glass is thermally dependent on the air layer to increase the thermal resistance. Therefore, the insulating effect of hollow glass can be significantly improved.

3. Vacuum insluating glass

The vacuum degree between the glasses is 10-4 Pa, so the thermal convection no longer exists, the heat conduction is reduced to the limit, and the Low-E layer reflects more than 95% of the infrared radiation. Therefore, the heat between the inner and outer glass plates cannot be exchanged, achieving excellent thermal insulation effect. The Low-E coating in the composite vacuum glass can effectively reflect infrared rays and block the heat out of the window. Just turn on the air conditioner for a short time every day to ensure the cool of the indoor day. It can not only save electricity, but also keep users away from the trouble of air conditioning diseases.

Therefore, energy saving vacuum insulating glass is the best choice as building glass for ultra-low energy consumption buildings.