Load control system having an energy savings mode

• US 8,571,719 B2
• Filed: 07/28/2010
• Issued: 10/29/2013
• Est. Priority Date: 07/30/2009
• Status: Active Grant

• Current Assignee: Lutron Technology Company LLC
• Original Assignee: Lutron Electronics Company Incorporated (Lutron Electronics)
• Inventors: Altonen, Gregory, Fricke, William Bryce, Jacoby, Elliot G., Pessina, Michael W., Zaharchuk, Walter S., Spira, Joel S.
• Primary Examiner(s): Ali, Mohammad
• Assistant Examiner(s): WHITTINGTON, ANTHONY T
• Application Number:
  US12/845,070
• Publication Number:
  US 20110029139A1
• Time in Patent Office: 1,189 Days
• Field of Search: 700/287, 160/5, 315/149
• US Class Current: 700/287
• CPC Class Codes: E06B 9/68 Operating devices or mechanisms, e.g. with electric drive
• CPC Class Codes: G05D 23/192 using a modification of the thermal impedance between a source and the load
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A load control system for a building having a heating and cooling system and a window located in a space of the building controls amount of daylight entering the window in order to attempt to reduce the power consumption of the heating and cooling system, and adjusts amount of daylight entering the window if the heating and cooling system is not saving energy. A motorized window treatment of the load control system is operable to move a fabric covering the window in a first direction, and a temperature control device is operable to subsequently determine if the heating and cooling system is consuming more energy than when the fabric was in the initial position. The motorized window treatment then moves the fabric in a second direction opposite the first direction if the heating and cooling system is consuming more energy than when the fabric was in the initial position.

Claims

1. A load control system for use in a building having a heating and cooling system and a window located in a space of the building, the load control system comprising:

a temperature control device for controlling a setpoint temperature of the heating and cooling system to thus control a present temperature in the building; and

a motorized window treatment for controlling a window treatment covering to an initial position between a fully open position in which the window is not covered and a fully-closed position in which the window is covered;

wherein after the motorized window treatment moves the covering in a first direction from the initial position towards the fully open position to allow more sunlight to enter the space when the heating and cooling system is heating the building, the load control system determines if the heating and cooling system is consuming more energy than when the covering was in the initial position; and

wherein if the heating and cooling system is consuming more energy than when the covering was in the initial position, the motorized window treatment moves the covering in a second direction towards the fully-closed position.

2. The load control system of claim 1, wherein the load control system is responsive to a demand response command.

3. The load control system of claim 2, wherein the motorized window treatment moves the covering in the first direction in response to the demand response command when a calculated position of the sun indicates that there is direct sunlight on the window.

4. The load control system of claim 3, wherein the motorized window treatment opens the covering from the initial position to allow more sunlight to enter the space in response to the demand response command when the heating and cooling system is heating the building, the motorized window treatment closing the covering if the heating and cooling system is consuming more energy than when the covering was in the initial position.

5. The load control system of claim 4, wherein, if the heating and cooling system is consuming more energy than when the covering was in the initial position, the motorized window treatment closes the covering to the fully-closed position.

6. The load control system of claim 3, wherein the motorized window treatment closes the covering from the initial position to allow less sunlight to enter the space in response to the demand response command when the heating and cooling system is cooling the building.

7. The load control system of claim 2, wherein the temperature control device, in response to the demand response command, automatically increases the setpoint temperature of the heating and cooling system when the heating and cooling system is presently cooling the building so as to decrease the power consumption of the heating and cooling system, and decreases the setpoint temperature of the heating and cooling system when the heating and cooling system is presently heating the building so as to decrease the power consumption of the heating and cooling system.

8. The load control system of claim 1, wherein the load control system monitors the heating and cooling system for a predetermined time period after the covering is moved from the initial position to determine if the heating and cooling system is consuming more energy than when the covering was in the initial position.

9. The load control system of claim 8, wherein the load control system stores data representative of energy usage information of the heating and cooling system in order to determine if the heating and cooling system is consuming more energy than when the covering was in the initial position.

10. The load control system of claim 9, wherein the data representative of energy usage information of the heating and cooling system comprises values of a duty cycle defining when the heating and cooling system is active and inactive during the predetermined time period, and the load control system monitors when the heating and cooling system is active or inactive to determine values of the duty cycles during the predetermined time period.

11. The load control system of claim 9, wherein the data representative of energy usage information of the heating and cooling system comprises a rate at which the temperature decreases or increases in the space when the heating and cooling system is not actively heating or cooling the space, respectively, during the predetermined time period.

12. The load control system of claim 8, wherein the length of the predetermined time period is approximately one hour.

13. The load control system of claim 1, wherein the temperature control device transmits a request for energy usage information from the heating and cooling system in order to determine if the heating and cooling system is consuming more energy than when the covering was in the initial position.

14. The load control system of claim 1, further comprising:

a lighting control device for controlling the amount of power delivered to the lighting load, the lighting control device decreasing the amount of power delivered to the lighting load in response to the demand response command so as to decrease the power consumption of the lighting load.

15. A method of controlling a motorized window treatment comprising a window treatment covering for a window in a space of the building, the building having a heating and cooling system, the method comprising:

moving the covering to an initial position between a fully open position in which the window is not covered and a fully-closed position in which the window is covered;

subsequently moving the covering from the initial position in a first direction towards a fully open position to allow more sunlight to enter the space;

monitoring the heating and cooling system for a predetermined time period after the fabric covering is moved from the initial position in a first direction;

storing data representative of energy usage information of the heating and cooling system in response to monitoring the heating and cooling system;

determining if the heating and cooling system is consuming more energy than when the covering was in the initial position by using the data representative of energy usage information of the heating and cooling system; and

moving the covering in a second direction opposite the first direction towards the fully-closed position if the heating and cooling system is consuming more energy than when the covering was in the initial position.

16. The method of claim 15, wherein the data representative of energy usage information of the heating and cooling system comprises values of a duty cycle defining when the heating and cooling system is active and inactive during the predetermined time period;

and

wherein monitoring the heating and cooling system comprises monitoring when the heating and cooling system is active or inactive to determine values of the duty cycles during the predetermined time period.

17. The method of claim 15, wherein the data representative of energy usage information of the heating and cooling system comprises a rate at which the temperature decreases or increases in the space when the heating and cooling system is not actively heating or cooling the space, respectively, during the predetermined time period.

18. The method of claim 15, wherein the length of the predetermined time period is approximately one hour.

19. The method of claim 15, further comprising:

receiving a demand response command;

determining a calculated position of the sun; and

determining if the window is receiving direct sunlight in response to the calculated position of the sun;

wherein the covering is moved in the first direction from the initial position in response to receiving the demand response command when there is direct sunlight on the window.

20. The method of claim 19, wherein moving the covering in a first direction comprises opening the covering from the initial position to allow more sunlight to enter the space in response to the demand response command when the heating and cooling system is heating the building, and moving the covering in a second direction comprises closing the covering if the heating and cooling system is consuming more energy than when the covering was in the initial position.

21. The method of claim 15, further comprising:

wherein monitoring the heating and cooling system comprises receiving energy usage information from the heating and cooling system in order to determine if the heating and cooling system is consuming more energy than when the covering was in the initial position.