How to save energy in Windows

China's door and window industry with the rapid development of the economy and forward development. With the continuous advent of new materials, doors and windows industry will be high-end, new, multifunctional, multi-species, a variety of real energy-saving development. Windows and doors seize this historic opportunity to develop truly energy-efficient windows and doors.

Correct understanding of "energy-saving windows"
Energy-saving window is the development direction of our industry, how to recognize energy-saving windows, how to calculate energy-saving, must be from the thermal conduction of three elements: the heat loss of thermodynamics (heat exchange) and heat convection, conduction and radiation to understand. Convection is the circulation of hot and cold air flow in the space between doors and windows, causing the gas to generate convection to drive heat exchange, and the circulation of hot cold air to generate heat loss. Heat conduction is the transfer of heat through the movement of the molecules of the material itself, and the heat conduction passes through the object itself to another opposite surface. Radiant heat transfer is the direct transmission of energy by means of radiation, infrared rays. No matter what material is made of windows, such as the above 3 kinds of heat exchange the most effective blocking and control, can be called the best energy-saving window.

Analysis of two key elements of energy-saving windows
In order to better achieve 3 kinds of heat exchange blocking, to achieve a real energy-saving window, to be considered from the following aspects:
Window type is the first element of energy-saving windows
Sliding window is not energy-saving window, flat window, fixed window is energy-saving window. First of all, from the window structure design considerations, the structure of the window to energy-saving plays a major role. such as sliding window in the window frame slide back and forth, there is a large space, under the gap between the pulley, the sash up and down to form a clear convection exchange, hot cold air convection formation of a large heat loss, convection size, heat loss and the size of the sash up and down space proportional. At this time with what insulation profiles for window frames can not reach the energy-saving effect, it is said that whether aluminum alloy or plastic-made push-pull windows are not qualified to be called energy-saving windows.

Casement window, sash and window frame generally normal with good rubber seal layering, after the casement closed, sealing rubber layering pressure is very tight, almost no gap, it is difficult to form convection. This window type of heat loss is mainly glass, sash and window frame profiles, heat conduction and radiant heat dissipation, this heat dissipation far less than the convection heat loss, if it can be a good solution to the above glass and window frame profile heat conduction, casement window energy saving effect is far more than the sliding window energy saving effect has obvious advantages, flat window can be called "energy-saving

Fixed window, window frame embedded in the wall, glass directly mounted on the window frame, glass and window frame has now used sealant instead of rubber strip seal, contact with the four sides are sealed, such as sealing sealant tight, the air is difficult to form through the sealant convection, it is difficult to cause heat loss. The heat transfer of glass and window frame of fixed window is the source of main heat loss, and effective measures can be taken on the glass to improve the energy saving effect greatly. Structurally speaking, fixed windows are the most energy-efficient window type. In order to ventilate ventilation in the fixed window to open a small upside-down window, or on the side of the fixed window to install a small flat window, dedicated to use as a regular lookout.

Now there are flat hanging, all kinds of sliding windows, as well as various types of external open, internal open and other window type, but are in the push-pull, flat open and fixed three types of windows within the change only.

Glass is the second element of energy-saving windows
In addition to the window structure, the maximum heat conduction and radiation area of the window is glass. The main cooling of the glass depends on heat conduction and heat radiation, conduction is heat from the glass inside the glass through the molecular movement of the heat conduction to the outer surface of the window. The size and conduction speed of the heat conduction, the thickness of the glass, the thermal conductivity of different glass, but also the properties of different properties of the glass, radiation and different properties of the glass.

1. Heat-reflective coated glass
Has better control of the optical performance, the wavelength of 0.3-2.5mm solar light has a good reflection and absorption capacity, can significantly reduce the sun's radiant energy to the indoor transmission, maintain stable indoor temperature, can save energy.

In general, the thermal reflective coating glass has been able to meet the needs of general energy-saving windows, such as higher requirements, as well as insulating glass and heat-reflective coating insulating glass and low-emissivity coated glass, but have its characteristics and different uses.

2. Insulating Glass
Insulating glass not only has excellent daylighting performance, but also has the special advantages of heat insulation, sound insulation, frost-proof and so on. Insulating glass has excellent thermal insulation performance, under certain conditions its thermal insulation performance can be better than the general concrete wall. The insulating capacity of insulating glass mainly comes from the air layer sealed by two layers of glass. The thermal conductivity of the air is 0.028W/MK, and the thermal conductivity of the glass is 0.77W/MK, the sealed insulating glass in addition to the glass four-sided with the sealant heat conduction, the rest of the large area of glass rely on the air layer heat conduction, increase thermal resistance. Therefore, the insulating effect of insulating glass can be improved obviously.

3. Low-emissivity coated glass
Low-emissivity coated glass is also known as (e-poor translation of Lou Yi Glass). According to the production method, can be divided into "online low-E glass" and "off-line low-E glass." Online Low-E glass, that is, in the float glass production line, generally the tin gas directly sprayed to the molten metal surface, with the cooling of the glass, the metal layer becomes a part of the glass, its characteristics, can be used directly in the air, can be tempered, hot bending, can be long-term preservation, its disadvantage is poor thermal performance. Compared to the "off-line" sputtering production of low-E Glass "U" value of nearly half, window glass insulation performance is generally used "U" value to indicate that "U" value and the glass emissivity has a direct relationship, "U" value is lower, the lower the heat transfer through the glass, the better the heat transfer performance of window glass.

Another method, sputtering production of low-E glass (also known as offline Low-E glass), the production method is the metal silver directly by sputtering method plating on the glass surface, its disadvantage is that the silver film layer is very fragile, and easy to generate silver oxide layer, so, it can not be used as ordinary glass, must be made of insulating glass, Can not be long-term preservation and transport before making insulating glass.

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How to save energy in Windows