Reducing edge losses in multilayer curtain type window shutters

One limiting factor in achieving optimum thermal peformance in shutters is air leakage around the shutter edges. A motor driven shutter using multilayer curtains employing a magnetic type edge seal is described. Using a controlled environment chamber the thermal performance of some shutters of this type was measured. Two layer and four layer shutters were tested and found to have thermal resistances of 0.81 m/sup 2/-/sup 0/C/W and 1.22 m/sup 2/-C/W respectively. The two layer shutter performed as well as a similarly sized unit in which the layers were permanently sealed. Although adequate, the four layer unit did not perform as well as expected, likely because of air leakage between cells at the top of the shutter.