In winter, the vent is shut down. By the greenhouse effect, the air in inter layer is heated and temperature at internal surface increases, and then energy-saving effects is achieved.

冬季关闭出风口，利用温室效应加热中间层的空气，提高内表面温度，达到节能效果。

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In winter, the vent is shut down. By the greenhouse effect, the air in inter layer is heated and temperature at internal surface increases, and then energy-saving effects is achieved.

冬季关闭出风口，利用温室效应加热中间层的空气，提高内表面温度，达到节能效果。

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