An apparatus and method for collecting solar energy are provided. The apparatus is a trough-type solar collector having one or more mirrors and lenses for directing solar radiation toward a receiver configured to receive a heat transfer fluid therein. The amount of solar radiation directed toward the receiver can be controlled by adjusting one or more of the mirrors and / or lenses or by adjusting a shade. Thus, the collector can direct different amounts or solar radiation toward the receiver, thereby selectively heating the receiver at different rates, e.g., to preheat the receiver, to heat fluid in the receiver for power generation, or to thaw solidified fluid in the receiver. Subsequently, the heated fluid can be used to generate steam and / or electricity.
An apparatus and method for collecting solar energy are provided. The apparatus is a trough-type solar collector having one or more mirrors and lenses for directing solar radiation toward a receiver configured to receive a heat transfer fluid therein. The amount of solar radiation directed toward the receiver can be controlled by adjusting one or more of the mirrors and / or lenses or by adjusting a shade. Thus, the collector can direct different amounts or solar radiation toward the receiver, thereby selectively heating the receiver at different rates, e.g., to preheat the receiver, to heat fluid in the receiver for power generation, or to thaw solidified fluid in the receiver. Subsequently, the heated fluid can be used to generate steam and / or electricity.
Disclosed is a light-emitting diode drive device that improves the utilization efficiency and power factor of LEDs while maintaining power supply efficiency. Said light-emitting diode drive device is provided with: a rectification circuit (2) that can be connected to an AC power supply and rectifies the AC voltage from said AC power supply into a pulsed voltage; a first LED block (11) comprising a plurality of light-emitting diodes, a second LED block (12) comprising a plurality of light-emitting diodes, and a third LED block (13) comprising a plurality of light-emitting diodes, connected sequentially in series to the output side of the rectification circuit (2); a first switching means that turns a first bypass path (BP1), which bypasses the second LED block (12), on or off on the basis of the amount of power supplied to the first LED block (11); and a second switching means that turns a second bypass path (BP2), which bypasses the third LED block (13), on or off on the basis of the amount of power supplied to the first LED block (11) and the second LED block (12).