Patent Application
20110235328
This disclosure relates to energy harvesting, and more particularly to an energy harvester for a light-emitting diode (“LED”) luminaire.
LEDs have been used in luminaires to provide illumination and act as light-bulb replacements. Heatsinks have been used to dissipate heat from LEDs, because LEDs may become very hot while emitting light.
According to one non-limiting embodiment, a light-emitting diode luminaire includes at least one light-emitting diode and at least one thermoelectric generator in contact with a portion of the luminaire. The at least one thermoelectric generator is operable to harvest energy from heat dissipated by the at least one light-emitting diode. An energy management module is operable to receive energy harvested by the at least one thermoelectric generator.
According to one non-limiting embodiment, a light-emitting diode luminaire includes at least one light-emitting diode. A heatsink is operable to provide a path for heat dissipation away from the at least one light-emitting diode. At least one thermoelectric generator is in contact with a portion of the luminaire and is operable to harvest energy from heat dissipated by the at least one light-emitting diode. An energy management module is operable to receive and store energy harvested by the at least one thermoelectric generator.
According to one non-limiting embodiment, a method of operating a light-emitting diode luminaire includes passing current from a power source through at least one light-emitting diode to emit light, harvesting thermal energy from heat dissipated by the at least one light-emitting diode using at least one thermoelectric generator, and using the harvested thermal energy through an energy management module to provide power to a load.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
A heat sink 18 is operable to provide a path for heat dissipation away from the plurality of LEDs 12. The heat sink includes first planar portion 18a in contact with the PCB 14, includes a second portion 18b transverse to the first portion, and includes a third housing portion 18c. The heatsink housing portion 18c surrounds the plurality of light-emitting diodes 12, the PCB 14 and the heat sink portions 18a-b.
The housing portion 18c includes a plurality of openings 23 through which light from the LEDs 12 may exit the housing. Each opening 23 has an associated optics portion 24 through which the light passes. In one example, each optics portion 24 is located beneath one of the plurality of LEDs 12. The optics portions 24 may include light pipes or light diffusers, for example. A connector 26 is able to detachably connect the luminaire 10 to a power source. In one example the connector 26 receives a DC voltage. In one example the connector 26 receives an AC voltage and performs an AC/DC conversion to provide a DC voltage to the plurality of LEDs 12.
The luminaire 10 includes one or more thermoelectric generators 28 that are in contact with the luminaire 10 and that are operable to harvest energy from heat dissipated by the plurality of LEDs 12. In one example the thermoelectric generators include Peltier devices. Of course, other thermoelectric generators 28 could be used. The thermoelectric generators 28 may be secured to the various heatsink portions 18a-c, for example. The thermoelectric generators 28 are able to harvest the most energy when placed in locations where the device has the largest temperature differential on each side. Therefore, a location such as the heatsink 18 can work well because one side of the generator 28 is secured to a hot surface and the other side of the generator 28 may be exposed to air that is cooler than the hot surface.
An energy storage and management module 30 receives and stores energy received from the thermoelectric generators 28. In one example the energy storage and management module 30 may be stored within the heatsink portion 18b. Of course, this is only an example and other locations would be possible. The energy storage and management module 30 may be used to power sensor 22, which may be a motion sensor, for example. In one example the luminaire 10 is configured to only turn OFF after a certain period of time if the sensor 22 detects no motion. Of course, other types of sensors could be used.
The energy storage and management module 30 may be used to provide at least a portion of the power for the LED control electronics (e.g. control 16) or the LED luminaire 10 itself. In one example the energy storage and management module 30 may omit storage functionality such that the module 30 only controls energy while the thermoelectric generators 28 are harvesting energy, and the module 30 does not provide power when the thermoelectric generators 28 are not harvesting energy.
Although multiple thermoelectric generators 28 and multiple thermoelectric generator 28 locations have been disclosed, it is understood that the disclosed quantity of thermoelectric generators 28 and the disclosed thermoelectric generator 28 locations are only examples. Also, it is understood that the luminaire 10 is only an example and that other LED luminaires could be used.
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
