| 摘要 |
A solar structure, and more particularly a greenhouse, comprising a framework formed from frame members (20, 20a) and a flexible cover (26) having portions (28) of varying optical density (A, B, C) along its length, and wound between a pair of opposed spools (24) mounted on respective sides of the framework such that the cover is wound from one spool to the opposed spool. The cover is constrained to move over rollers (22) extending longitudinally of the framework, and the edges of the cover are received to move within slots (25) formed in the edges of the frame members. The flexible cover (26) may be formed as panels (A, B and C) having adjacent lengths of material (28) of differing optical densities. The lengths (28) are arranged sequentially along the cover (26) and may be transparent, translucent or opaque. Some of the lengths may have heat insulating and/or heat reflective properties and some may be foraminous to provide regions of different optical density and ventilation. The longitudinal ends (30) of adjacent lengths (28) are joined by a seam. Alternatively the flexible cover (26) may be formed from a single length of material having a different optical density along its length. |
