SMART WIDOW SYSTEM INCLUDING ENERGY STORAGE UNIT AND METHODS OF USING SAME
A method of operating an electrochromic (EC) device includes storing energy generated by the EC device during a change in optical state of the EC device.
1 . A smart window system, comprising:
an electrochromic (EC) device having a bright optical state and a dark optical state;
a DC/DC power converter electrically connected to the EC device and configured to operate in a buck mode and a boost mode; and
an energy storage device electrically connected to the power converter,
wherein:
in the buck mode, the power converter is configured to decrease a voltage provided through the power converter to the EC device; and
in the boost mode, the power converter is configured to increase a voltage provided from the EC device to the energy storage device.
2 . The system of claim 1 , wherein the power converter comprises:
an inductor electrically connected to the EC device; and
a switch configured to control current flow through the inductor.
3 . The system of claim 2 , wherein:
when the switch is in a first position, the energy storage device, the inductor, and the EC device are electrically connected; and
when the switch is in a second position, the inductor and the EC device are electrically connected, and the energy storage device is electrically disconnected from the inductor and the EC device.
4 . The system of claim 2 , wherein in the boost mode, the power converter is configured to use the inductor to:
accumulate current due to photochromic charge generated by UV light striking the EC device; and
use the accumulated current to boost the voltage provided from the EC device to the energy storage device.
5 . The system of claim 2 , wherein:
in the buck mode, the switch is configured to allow current to flow through the inductor in a first direction; and
in the boost mode, the switch is configured to allow the current to flow though the inductor in an opposing second direction.
6 . The system of claim 1 , wherein the energy storage device comprises a battery or a capacitor.
7 . The system of claim 1 , further comprising a power supply configured to provide power to the EC device, the energy storage device, or both the EC device and the energy storage device.
8 . The system of claim 1 , wherein the power supply comprises an independent power supply, a power generation device disposed in or on the smart window system, or both the independent power supply and the power generation device disposed in or on the smart window system.
9 . The system of claim 8 , wherein the power supply comprises the photovoltaic power generation device disposed in or on the smart window system.
10 . The system of claim 1 , wherein the EC device comprises:
a first transparent conductor layer;
a working electrode comprising a nanostructured electrochemically-active material;
a solid state electrolyte layer;
a counter electrode layer; and
a second transparent conductor layer.
11 . A method of operating an electrochromic (EC) device, comprising storing energy generated by the EC device during a change in optical state of the EC device.
12 . The method of claim 11 , wherein the energy is stored in an energy storage device selected from a battery and a capacitor.
13 . The method of claim 11 , wherein the change of optical state of the EC device comprises an intentional change from a dark optical state to a bright optical state of the EC device.
14 . The method of claim 11 , wherein the change of optical state of the EC device comprises photochromic darkening which results in accumulation of photochromic charge in the EC device.
15 . The method of claim 14 , further comprising removing the photochromic charge from the EC device to brighten the EC device and to provide a current to an energy storage device to store the energy.
16 . The method of claim 15 , further comprising determining if the EC device is set into a bright optical state and removing the photochromic charge from the EC device if the EC device is set into the bright optical state.
17 . The method of claim 11 , further comprising:
operating a DC/DC power converter in a buck mode, such that the DC/DC power converter reduces a voltage provided to the EC device; and
operating the DC/DC power converter in a boost mode, such that the DC?DC power converter increases a voltage provided from the EC device to an energy storage device.
18 . The method of claim 17 , wherein the voltage provided from the EC device is provided during a change in the optical state of the EC device.
19 . The method of claim 17 , wherein the voltage provided from the EC device is provided to remove photochromic charge accumulated in the EC device.
20 . The method of claim 17 , wherein the DC/DC power converter comprises an inductor and a switch.
21 . A smart window system, comprising
an electrochromic (EC) device having a bright optical state and a dark optical state;
an energy storage device electrically connected to the power converter; and
a conversion means for increasing a voltage provided to the EC device in a buck mode, and for increasing a voltage provided from the EC device to the energy storage device in a boost mode.