Insulation strips significantly reduce the solar transmittance ratio

Time: 2023-06-25

It is well known that nylon insulation strips can significantly reduce the heat transfer coefficient (U-value) of the whole window, thus reducing the building energy consumption. Is it useless in the hot southern region where cooling is the main requirement and the temperature difference is small?

The performance of g-value and energy consumption is simulated for aluminum casement windows with 14.8mm and 24mm (foam-filled) insulation bars without external shading. To simplify the variables, a glass-to-frame ratio of 75%, a common total solar transmittance ratio of 0.35 for glass gg, and a glass Ug value of 1.8 W/(m².K) were assumed. In either configuration, the solar heat gain Φsf of the window frame is more than three times the temperature difference heat gain ΦTf of the window frame.

In most cases, it is even greater than the whole window heat gain through the temperature difference ΦTw. This indicates that the main function of the insulated window frame in summer areas where cooling is predominant is not to reduce the Uf value, but to reduce the gf through the frame. As the width of the insulating strip increases from 14.8 to about 24 mm, the percentage of decrease in gf value further decreases from 39% to 57% compared to the plain aluminum window, and the whole window g value also decreases to 9% . It shows that the use of high thermal insulating performance window frame can further reduce the solar transmittance ratio of the whole window significantly.

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Insulation strips make your house more comfortable