| 摘要 |
<p>A shield c which rotates around an evacuated solar thermal tube e to provide shading when required, the shield rotates longitudinally around the solar tubing. The shield may be usable to reflect light onto the solar thermal tube when not used to cover the tube. The shield may be activated by a piston connected to the coolant liquid passing through the solar thermal tubing. The shield may be activated to rotate and cover the tube when the temperature reaches a set point. The shield may extend along the whole solar thermal tube or only part thereof. Preferably the shield is reflective to aid in directing light onto the tube when not covering the tube.</p> |
