Load control system having an energy savings mode

A load control system for a building having a heating and cooling system and a window located in a space of the building is operable to control a motorized window treatment in response to a demand response command in order to attempt to reduce the power consumption of the heating and cooling system. When the window may be receiving direct sunlight, the motorized window treatment closes a fabric covering the window when the heating and cooling system is cooling the building, and opens the fabric when the heating and cooling system is heating the building. In addition, when the space is unoccupied and the heating and cooling system is heating the building, the motorized window treatment may open the fabric if the window may be receiving direct sunlight, and may close the fabric if the window may not be receiving direct sunlight.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a load control system for a plurality of electrical loads in a building, and more particularly, to a load control system for controlling the lighting intensities of lighting loads, the positions of motorized window treatments, and the temperature of the building in order to reduce the total power consumption of the load control system.

2. Description of the Related Art

Reducing the total cost of electrical energy is an important goal for many electricity consumers. The customers of an electrical utility company are typically charged for the total amount of energy consumed during a billing period. However, since the electrical utility company must spend money to ensure that its equipment (e.g., an electrical substation) is able to provide energy in all situations, including peak demand periods, many electrical utility companies charge their electricity consumers at rates that are based on the peak power consumption during the billing period, rather than the average power consumption during the billing period. Thus, if an electricity consumer consumes power at a very high rate for only a short period of time, the electricity consumer will face a significant increase in its total power costs.

Therefore, many electricity consumers use a “load shedding” technique to closely monitor and adjust (i.e., reduce) the amount of power presently being consumed by the electrical system. Additionally, the electricity consumers “shed loads”, i.e., turn off some electrical loads, if the total power consumption nears a peak power billing threshold established by the electrical utility. Prior art electrical systems of electricity consumers have included power meters that measure the instantaneous total power being consumed by the system. Accordingly, a building manager of such an electrical system is able to visually monitor the total power being consumed. If the total power consumption nears a billing threshold, the building manager is able to turn off electrical loads to reduce the total power consumption of the electrical system.

Many electrical utility companies offer a “demand response” program to help reduce energy costs for their customers. With a demand response program, the electricity consumers agree to shed loads during peak demand periods in exchange for incentives, such as reduced billing rates or other means of compensation. For example, the electricity utility company may request that a participant in the demand response program shed loads during the afternoon hours of the summer months when demand for power is great. Examples of lighting control systems that are responsive to demand response commands are described in greater detail in commonly-assigned U.S. patent application Ser. No. 11/870,889, filed Oct. 11, 2007, entitled METHOD OF LOAD SHEDDING TO REDUCE THE TOTAL POWER CONSUMPTION OF A LOAD CONTROL SYSTEM, and U.S. Pat. No. 7,747,357, issued Jun. 29, 2010, entitled METHOD OF COMMUNICATING A COMMAND FOR LOAD SHEDDING OF A LOAD CONTROL SYSTEM, the entire disclosures of which are hereby incorporated by reference.

Some prior art lighting control systems have offered a load shedding capability in which the intensities of all lighting loads are reduced by a fixed percentage, e.g., by 25%, in response to an input provided to the system. The input may comprise an actuation of a button on a system keypad by a building manager. Such a lighting control system is described in commonly-assigned U.S. Pat. No. 6,225,760, issued May 1, 2001, entitled FLUORESCENT LAMP DIMMER SYSTEM, the entire disclosure of which is hereby incorporated by reference.

Some prior art load control systems have provided for control of both electrical lighting loads (to control the amount of artificial light in a space) and motorized window treatments (to control the amount of daylight entering the space). Such load control systems have operated to achieve a desired lighting intensity on task surfaces in the space, to maximize the contribution of the daylight provided to the total light illumination in the space (i.e., to provide energy savings), and/or to minimize sun glare in the space. An example of a load control system for control of both electrical lighting loads and motorized window treatments is described in greater detail in commonly-assigned U.S. Pat. No. 7,111,952, issued Sep. 26, 2006, entitled SYSTEM TO CONTROL DAYLIGHT AND ARTIFICIAL ILLUMINATION AND SUN GLARE IN A SPACE, the entire disclosure of which is hereby incorporated by reference.

In addition, prior art heating, ventilation, and air-conditioning (HVAC) control systems for control of the temperature in a building and may operate to minimize energy consumption. However, there exists a need for a single load control system that controls the lighting intensities of lighting loads, the positions of motorized window treatments, and the temperature of the building in order to reduce the total power consumption of the load control system.

SUMMARY OF THE INVENTION

According to an embodiment of the present invention, a load control system for a building having a heating and cooling system and a window located in a space of the building is operable to control a motorized window treatment in response to a demand response command in order to attempt to reduce the power consumption of the heating and cooling system. The motorized window treatment comprises a window treatment fabric for covering the window. The motorized window treatment is operable to move the fabric between a fully-open position in which the window is not covered and a fully-closed position in which the window is covered. The load control system further comprises a temperature control device operable to control a setpoint temperature of the heating and cooling system to thus control a present temperature in the building, and to determine whether the heating and cooling system is heating or cooling the building. When the window may be receiving direct sunlight, the motorized window treatment closes the fabric in response to the demand response command when the heating and cooling system is cooling the building, and opens the fabric in response to the demand response command when the heating and cooling system is heating the building.

In addition, a method of controlling a motorized window treatment comprising a window treatment fabric for covering a window in a space of the building is also described herein. The method comprises: (1) receiving a demand response command; (2) determining if the window may be receiving direct sunlight; (3) determining whether a heating and cooling system is heating or cooling the building; (4) closing the fabric in response to the demand response command when the window may be receiving direct sunlight and the heating and cooling system is cooling the building; and (5) opening the fabric in response to the demand response command when the window may be receiving direct sunlight and the heating and cooling system is heating the building.

According to another embodiment of the present invention, a load control system for a building having a heating and cooling system and a window located in a space of the building is operable to control a motorized window treatment in response to an occupancy sensor in order to attempt to reduce the power consumption of the heating and cooling system. The motorized window treatment comprises a window treatment fabric for covering the window and the occupancy sensor detects whether the space is occupied or unoccupied. The motorized window treatment is operable to move the fabric between a fully-open position in which the window is not covered and a fully-closed position in which the window is covered. The load control system further comprises a temperature control device operable to control a setpoint temperature of the heating and cooling system to thus control a present temperature in the building, and to determine whether the heating and cooling system is heating or cooling the building. When the space is unoccupied and the heating and cooling system is heating the building, the motorized window treatment opens the fabric if the window may be receiving direct sunlight, and closes the fabric if the window may not be receiving direct sunlight.

Further, a method of controlling a motorized window treatment comprising a window treatment fabric for covering a window in a space of the building comprises: (1) detecting whether the space is occupied or unoccupied; (2) determining if the window may be receiving direct sunlight; (3) determining whether a heating and cooling system is heating or cooling the building; (4) opening the fabric when the space is unoccupied, the heating and cooling system is heating the building, and the window may be receiving direct sunlight; and (5) closing the fabric if the space is unoccupied, the heating and cooling system is heating the building, and the window may be receiving direct sunlight.

DETAILED DESCRIPTION OF THE INVENTION

The foregoing summary, as well as the following detailed description of the preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purposes of illustrating the invention, there is shown in the drawings an embodiment that is presently preferred, in which like numerals represent similar parts throughout the several views of the drawings, it being understood, however, that the invention is not limited to the specific methods and instrumentalities disclosed.

FIG. 1is a simplified block diagram of a centralized load control system100that may be installed in a building (such as a commercial building) according to a first embodiment of the present invention. The load control system100comprises a multi-zone lighting control device110that is operable to control the amount of power delivered from an alternating-current (AC) power source (not shown) to one or more lighting loads112for adjusting the intensities of the lighting loads. The lighting load112may be located in a space160(FIG. 2) of the building to thus control the amount of electric light (i.e., artificial light) in the space. The lighting loads112may comprise, for example, incandescent lamps, halogen lamps, gas discharge lamps, fluorescent lamps, compact fluorescent lamps, high-intensity discharge (HID) lamps, magnetic low-voltage (MLV) lighting loads, electronic low-voltage (ELV) lighting loads, light-emitting diode (LED) light sources, hybrid light sources comprising two or more different types of lamps, and any other electrical light sources, or combination thereof, that provide illumination. In addition, the load control system100may comprise additional multi-zone lighting control devices110as well as single-zone lighting control devices, such as, electronic dimming ballasts, LED drivers, and dimmer switches.

The lighting control device110is operable to control a present lighting intensity LPRESof each of the lighting loads112from a minimum lighting intensity LMINto a maximum lighting intensity LMAX. The lighting control device110is operable to “fade” the present lighting intensity LPRES, i.e., control the present lighting intensity from a first lighting intensity to a second lighting intensity over a period of time. Fade rates of a lighting control device are described in greater detail in commonly-assigned U.S. Pat. No. 5,248,919, issued Sep. 29, 1993, entitled LIGHTING CONTROL DEVICE, the entire disclosure of which is hereby incorporated by reference.

The lighting control device110comprises a first set of buttons114, which may be actuated by a user to allow for manual control of the intensities of the lighting loads112, i.e., to allow an occupant to control the intensities of the lighting load112to desired intensity levels LDES. Actuations of the buttons114may cause the lighting control device110to select one or more lighting presets (i.e., “scenes”). The first set of buttons114may also comprise raise and lower buttons for respectively raising and lowering the intensities of all (or a subset) of the lighting loads112in unison. The lighting control device110is connected to a wired communication link116and is operable to transmit and receive digital messages via the communication link. Alternatively, the communication link could comprise a wireless communication link, such as, for example, a radio-frequency (RF) communication link or an infrared (IR) communication link.

The load control system100also comprises one or more daylight control devices, for example, motorized window treatments, such as motorized roller shades120. The motorized roller shades120of the load control system100may be positioned in front of one or more windows for controlling the amount of daylight (i.e., natural light) entering the building. The motorized roller shades120each comprise a flexible shade fabric122rotatably supported by a roller tube124. Each motorized roller shade120is controlled by an electronic drive unit (EDU)126, which may be located inside the roller tube124. The electronic drive unit126may be powered directly from the AC power source or from an external direct-current (DC) power supply (not shown). The electronic drive unit126is operable to rotate the respective roller tube124to move the bottom edge of the shade fabric122to a fully-open position and a fully-closed position, and to any position between the fully-open position and the fully-closed position (e.g., a preset position). Specifically, the motorized roller shades120may be opened to allow more daylight to enter the building and may be closed to allow less daylight to enter the building. In addition, the motorized roller shades120may be controlled to provide additional insulation for the building, e.g., by moving to the fully-closed position to keep the building cool in the summer and warm in the winter. Examples of electronic drive units for motorized roller shades are described in commonly-assigned U.S. Pat. No. 6,497,267, issued Dec. 24, 2002, entitled MOTORIZED WINDOW SHADE WITH ULTRAQUIET MOTOR DRIVE AND ESD PROTECTION, and U.S. Pat. No. 6,983,783, issued Jan. 10, 2006, entitled MOTORIZED SHADE CONTROL SYSTEM, the entire disclosures of which are hereby incorporated by reference.

Alternatively, the motorized roller shades120could comprise tensioned roller shade systems, such that the motorized roller shades120may be mounted in a non-vertical manner, for example, horizontally in a skylight. An example of a tensioned roller shade system that is able to be mounted in a skylights is described in commonly-assigned U.S. patent application Ser. No. 12/061,802, filed Apr. 3, 2008, entitled SELF-CONTAINED TENSIONED ROLLER SHADE SYSTEM, the entire disclosure of which in hereby incorporated by reference. In addition, the daylight control devices of the load control system100could alternatively comprise controllable window glazings (e.g., electrochromic windows), controllable exterior shades, controllable shutters or louvers, or other types of motorized window treatments, such as motorized draperies, roman shades, or blinds. An example of a motorized drapery system is described in commonly-assigned U.S. Pat. No. 6,935,403, issued Aug. 30, 2005, entitled MOTORIZED DRAPERY PULL SYSTEM, the entire disclosure of which in hereby incorporated by reference.

Each of the electronic drive units126is coupled to the communication link116, such that the electronic drive unit may control the position of the respective shade fabric122in response to digital messages received via the communication link. The lighting control device110may comprise a second set of buttons118that provides for control of the motorized roller shades120. The lighting control device110is operable to transmit a digital message to the electronic drive units126in response to actuations of any of the second set of buttons118. The user is able to use the second set of buttons118to open or close the motorized roller shades120, adjust the position of the shade fabric122of the roller shades, or set the roller shades to preset shade positions between the fully open position and the fully closed position.

The load control system100comprise one or more temperature control devices130, which are also coupled to the communication link116, and may be powered, for example, from the AC power source, an external DC power supply, or an internal battery. The temperature control devices130are also coupled to a heating, ventilation, and air-conditioning (HVAC) control system132(i.e., a “heating and cooling” system) via an HVAC communication link134, which may comprise, for example, a network communication link such as an Ethernet link. Each temperature is operable to control the HVAC system132to a cooling mode in which the HVAC system is cooling the building, and to a heating mode in which the HVAC system is heating the building. The temperature control devices130each measure a present temperature TPRESin the building and transmit appropriate digital messages to the HVAC system to thus control the present temperature in the building towards a setpoint temperature TSET. Each temperature control device130may comprise a visual display135for displaying the present temperature TPRESin the building or the setpoint temperature TSET. In addition, each temperature control device130may comprise raise and lower temperature buttons136,138for respectively raising and lowering the setpoint temperature TSETto a desired temperature TDESas specified by the occupant in the building. Each temperature control device130is also operable to adjust the setpoint temperature TSETin response to digital messages received via the communication link116.

The load control system100further comprises one or more controllable electrical receptacles140for control of one or more plug-in electrical loads142, such as, for example, table lamps, floor lamps, printers, fax machines, display monitors, televisions, coffee makers, and water coolers. Each controllable electrical receptacle140receives power from the AC power source and has an electrical output to which a plug of the plug-in electrical load142may be inserted for thus powering the plug-in load. Each controllable electrical receptacle140is operable to turn on and off the connected plug-in electrical load142in response to digital messages received via the communication link. In addition, the controllable electrical receptacles140may be able to control the amount of power delivered to the plug-in electrical load142, e.g., to dim a plug-in lighting load. Additionally, the load control system100could comprise one or more controllable circuit breakers (not shown) for control of electrical loads that are not plugged into electrical receptacles, such as a water heater.

The load control system100may also comprise a controller150, which may be coupled to the communication link116for facilitating control of the lighting control devices110, the motorized roller shades120, the temperature control devices130, and the controllable electrical receptacles140of the load control system100. The controller150is operable to control the lighting control devices110and the motorized roller shades120to control a total light level in the space160(i.e., the sum of the artificial and natural light in the space). The controller150is further operable to control the load control system100to operate in an energy savings mode. Specifically, the controller150is operable to transmit individual digital messages to each of the lighting control devices110, the motorized roller shades120, the temperature control devices130, and the controllable electrical receptacles140to control the intensities of the lighting loads112, the positions of the shade fabrics122, the temperature of the building, and the state of the plug-in electrical loads142, respectively, so as to reduce the total power consumption of the load control system100(as will be described in greater detail below). The controller150may be further operable to monitor the total power consumption of the load control system100.

The load control system100may further comprise an occupancy sensor152for detecting an occupancy condition or a vacancy condition in the space in which the occupancy sensor in mounted, and a daylight sensor154for measuring an ambient light intensity LAMBin the space in which the daylight sensor in mounted. The occupancy sensor152and the daylight sensor154may be coupled to the lighting control device110(as shown inFIG. 1). Alternatively, the occupancy sensor152and the daylight sensor154may be coupled to the communication link116or directly to the controller150.

The controller150is operable to control the lighting control device110, the motorized roller shades120, the temperature control devices130, and the controllable electrical receptacles140in response to an occupancy condition or a vacancy condition detected by the occupancy sensor152, and/or in response to the ambient light intensity LAMBmeasured by the daylight sensor154. For example, the controller150may be operable to turn on the lighting loads112in response to detecting the presence of an occupant in the vicinity of the occupancy sensor152(i.e., an occupancy condition), and to turn off the lighting loads in response to detecting the absence of the occupant (i.e., a vacancy condition). In addition, the controller150may be operable to increase the intensities of the lighting loads112if the ambient light intensity LAMBdetected by the daylight sensor154is less than a setpoint light intensity LSET, and to decrease the intensities of the lighting load if the ambient light intensity LAMBis greater than the setpoint light intensity LSET.

Examples of occupancy sensors are described in greater detail in co-pending, commonly-assigned U.S. patent application Ser. No. 12/203,500, filed Sep. 3, 2008, entitled BATTERY-POWERED OCCUPANCY SENSOR; and U.S. patent application Ser. No. 12/371,027, filed Feb. 13, 2009, entitled METHOD AND APPARATUS FOR CONFIGURING A WIRELESS SENSOR, the entire disclosures of which are hereby incorporated by reference. Examples of daylight sensors are described in greater detail in commonly-assigned U.S. patent application Ser. No. 12/727,923, filed Mar. 19, 2010, entitled METHOD OF CALIBRATING A DAYLIGHT SENSOR; and U.S. patent application Ser. No. 12/727,956, filed Mar. 19, 2010, entitled WIRELESS BATTERY-POWERED DAYLIGHT SENSOR, the entire disclosures of which are hereby incorporated by reference.

The controller150may also be connected to a network communication link156, e.g., an Ethernet link, which may be coupled to a local area network (LAN), such as an intranet, or a wide area network (WAN), such as the Internet. The network communication link156may also comprise a wireless communication link allowing for communication on a wireless LAN. For example, the controller150may be operable to receive a demand response (DR) command (e.g., an “immediate” demand response command) from an electrical utility company as part of a demand response program. In response to receiving an immediate demand response command, the controller150will immediately control the load control system100to reduce the total power consumption of the load control system.

According to alternative embodiments of the present invention, the demand response command may also comprise one of a plurality of demand response levels or a planned demand response command indicating an upcoming planned demand response event as will be describe in greater detail below. While the present invention is described with the controller150connected to the network communication link156for receipt of the demand response commands, the one or more of the lighting control devices110could alternatively be coupled to the network communication link156for control of the lighting loads112, the motorized roller shades120, the temperature control devices130, and the controllable electrical receptacles140in response to the demand response commands.

The controller150may comprise an astronomical time clock for determining the present time of day and year. Alternatively, the controller150could retrieve the present time of the year or day from the Internet via the network communication link156.

To maximize the reduction in the total power consumption of the load control system100, the controller150is operable to control the load control system100differently depending upon whether the HVAC system132is presently heating or cooling. For example, the controller150may increase the setpoint temperatures TSETof each of the temperature control devices130when the HVAC system132is presently cooling and may decrease the setpoint temperatures TSETwhen the HVAC system is presently heating in order to save energy. Alternatively, the controller150could control the setpoint temperature TSETof the temperature control device130differently depending on whether the present time of the year is during a first portion of the year, e.g., the “summer” (i.e., the warmer months of the year), or during a second portion of the year, e.g., the “winter” (i.e., the colder months of the year). As used herein, the “summer” refers to the warmer half of the year, for example, from approximately May 1 to approximately October 31, and the “winter” refers to the colder half of the year, for example, from approximately November 1 to approximately April 30. In addition, the controller150could alternatively control the setpoint temperature TSETof the temperature control device130differently depending on the temperature external to the building.

The controller150may be operable to operate in an “out-of-box” mode of operation immediately after being installed and powered for the first time. Specifically, the controller150may be operable to control the lighting control devices110, the motorized roller shades120, the temperature control devices130, and the controllable electrical receptacles140according to pre-programmed out-of-box settings in response to receiving a demand response command via the network communication link156. For example, in response to receiving the demand response command when in the out-of-box mode, the controller150may dim the lighting loads112by a predetermined percentage ΔLOOB, e.g., by approximately 20% of the present lighting intensity LPRES(such that the lighting loads112consume less power). In addition, the controller150may close all of the motorized roller shades120to provide additional insulation for the building (such that the HVAC system132will consume less power) in response to receiving the demand response command when in the out-of-box mode. Further, the controller150may adjust the setpoint temperatures TSETof the temperature control devices130in response in response to receiving the demand response command when in the out-of-box mode, for example, by increasing the setpoint temperatures TSETof each of the temperature control devices by a predetermined increment ΔTOOB(e.g., approximately 2° F.) when the HVAC system132is presently cooling the building, and decreasing the setpoint temperatures TSETof each of the temperature control devices by the predetermined increment ΔTOOBwhen the HVAC system is presently heating the building, such that the HVAC system will consume less power.

To maximize the reduction in the total power consumption of the load control system100, the controller150may be configured using an advanced programming procedure, such that the controller150operates in a programmed mode (rather than the out-of-box mode). For example, the controller150may be programmed to control the load control system100differently depending upon whether one or more of the windows of the building are receiving direct sunlight as will be described in greater detail below. The load control system100and the controller150may be programmed using, for example, a personal computer (PC) (not shown), having a graphical user interface (GUI) software. The programming information may be stored in a memory in the controller150.

In addition, the controller150or one of the other control devices of the load control system100may be able to provide a visual indication that load control system is operating in the energy savings mode (i.e., in response to a demand response command). For example, the lighting control device110could comprise a visual indicator, such as a light-emitting diode (LED), which may be illuminated when the load control system100is operating in the energy savings mode. An example of a lighting control device for providing a visual indication of an energy savings mode is described in greater detail in commonly-assigned U.S. patent application Ser. No. 12/474,950, filed May 29, 2009, entitled LOAD CONTROL DEVICE HAVING A VISUAL INDICATION OF AN ENERGY SAVINGS MODE, the entire disclosure of which is hereby incorporated by reference.

Alternatively, the load control system100could comprises a visual display, such as an liquid-crystal display (LCD) screen, for providing a visual indication in the load control system100is operating in the energy savings mode and for providing information regarding the total power consumption of the load control system and the amount of energy savings. An example of a visual display for providing energy savings information is described in greater detail in commonly-assigned U.S. patent application Ser. No. 12/044,672, filed Mar. 7, 2008, SYSTEM AND METHOD FOR GRAPHICALLY DISPLAYING ENERGY CONSUMPTION AND SAVINGS, the entire disclosure of which is hereby incorporated by reference.

The controller150is operable to transmit digital messages to the motorized roller shades120to control the amount of sunlight entering the space160of the building to limit a sunlight penetration distance dPENin the space. The controller150comprises an astronomical timeclock and is able to determine a sunrise time tSUNRISEand a sunset time tSUNSETfor a specific day of the year. The controller150transmits commands to the electronic drive units126to automatically control the motorized roller shades120in response to a shade timeclock schedule as will be described in greater detail below. An example of a method of limiting the sunlight penetration distance dPENis a space is described in greater detail in commonly-assigned commonly-assigned U.S. patent application Ser. No. 12/563,786, filed Sep. 21, 2009, entitled METHOD OF AUTOMATICALLY CONTROLLING A MOTORIZED WINDOW TREATMENT WHILE MINIMIZING OCCUPANT DISTRACTIONS, the entire disclosure of which is hereby incorporated by reference.

FIG. 2is a simplified side view of an example of the space160illustrating the sunlight penetration distance dPEN, which is controlled by one of the motorized roller shades120. As shown inFIG. 2, the building comprises a façade164(e.g., one side of a four-sided rectangular building) having a window166for allowing sunlight to enter the space. The space160also comprises a work surface, e.g., a table168, which has a height hWORK. The motorized roller shade120is mounted above the window166, such that the shade fabric122hangs in front of the window, so as to control the amount of daylight (i.e., natural light) that is admitted through the window. The electronic drive unit126rotates the roller tube172to move the shade fabric170between a fully open position (in which the window166is not covered) and a fully closed position (in which the window166is fully covered). Further, the electronic drive unit126may control the position of the shade fabric170to one of a plurality of preset positions between the fully open position and the fully closed position.

The sunlight penetration distance dPENis the distance from the window166and the façade164at which direct sunlight shines into the room. The sunlight penetration distance dPENis a function of a height hWINof the window166and an angle φFof the façade164with respect to true north, as well as a solar elevation angle θSand a solar azimuth angle φS, which define the position of the sun in the sky. The solar elevation angle θSand the solar azimuth angle φSare functions of the present date and time, as well as the position (i.e., the longitude and latitude) of the building in which the space160is located. The solar elevation angle θSis essentially the angle between a line directed towards the sun and a line directed towards the horizon at the position of the building. The solar elevation angle θScan also be thought of as the angle of incidence of the sun's rays on a horizontal surface. The solar azimuth angle φSis the angle formed by the line from the observer to true north and the line from the observer to the sun projected on the ground.

The sunlight penetration distance dPENof direct sunlight onto the table168of the space160(which is measured normal to the surface of the window166) can be determined by considering a triangle formed by the length l of the deepest penetrating ray of light (which is parallel to the path of the ray), the difference between the height hWINof the window166and the height hWORKof the table168, and distance between the table and the wall of the façade164(i.e., the sunlight penetration distance dPEN) as shown in the side view of the window166inFIG. 3A, i.e.,
tan(θS)=(hWIN−hWORK)/l,(Equation 1)
where θSis the solar elevation angle of the sun at a given date and time for a given location (i.e., longitude and latitude) of the building.

If the sun is directly incident upon the window166, a solar azimuth angle φSand the façade angle φF(i.e., with respect to true north) are equal as shown by the top view of the window166inFIG. 3B. Accordingly, the sunlight penetration distance dPENequals the length l of the deepest penetrating ray of light. However, if the façade angle φFis not equal to the solar azimuth angle φS, the sunlight penetration distance dPENis a function of the cosine of the difference between the façade angle φFand the solar azimuth angle φS, i.e.,
dPEN=l·cos(|φF−φS|),  (Equation 2)
as shown by the top view of the window166inFIG. 3C.

As previously mentioned, the solar elevation angle θSand the solar azimuth angle φSdefine the position of the sun in the sky and are functions of the position (i.e., the longitude and latitude) of the building in which the space160is located and the present date and time. The following equations are necessary to approximate the solar elevation angle θSand the solar azimuth angle φS. The equation of time defines essentially the difference in a time as given by a sundial and a time as given by a clock. This difference is due to the obliquity of the Earth's axis of rotation. The equation of time can be approximated by
E=9.87·sin(2B)−7.53·cos(B)−1.5·sin(B),  (Equation 3)
where B=[360°·(NDAY−81)]/364, and NDAYis the present day-number for the year (e.g., NDAYequals one for January 1, NDAYequals two for January 2, and so on).

The solar declination δ is the angle of incidence of the rays of the sun on the equatorial plane of the Earth. If the eccentricity of Earth's orbit around the sun is ignored and the orbit is assumed to be circular, the solar declination is given by:
δ=23.45°·sin [360°/365·(NDAY+284)].  (Equation 4)
The solar hour angle H is the angle between the meridian plane and the plane formed by the Earth's axis and current location of the sun, i.e.,
H(t)={¼[t+E−(4·λ)+(60·tTZ)]}−180°,  (Equation 5)
where t is the present local time of the day, λ is the local longitude, and tTZis the time zone difference (in unit of hours) between the local time t and Greenwich Mean Time (GMT). For example, the time zone difference tTZfor the Eastern Standard Time (EST) zone is −5. The time zone difference tTZcan be determined from the local longitude λ and latitude Φ of the building. For a given solar hour angle H, the local time can be determined by solving Equation 5 for the time t, i.e.,
t=720+4·(H+λ)−(60·tTZ)−E.(Equation 6)
When the solar hour angle H equals zero, the sun is at the highest point in the sky, which is referred to as “solar noon” time tSN, i.e.,
tSN=720+(4·λ)−(60·tTZ)−E.(Equation 7)
A negative solar hour angle H indicates that the sun is east of the meridian plane (i.e., morning), while a positive solar hour angle H indicates that the sun is west of the meridian plane (i.e., afternoon or evening).

The solar elevation angle θSas a function of the present local time t can be calculated using the equation:
θS(t)=sin−1[ cos(H(t))·cos(δ)·cos(Φ)+sin(δ)·sin(Φ)],  (Equation 8)
wherein Φ is the local latitude. The solar azimuth angle θSas a function of the present local time t can be calculated using the equation:
φS(t)=180°·C(t)·cos−1[X(t)/cos(θS(t))],  (Equation 9)
where
X(t)=[ cos(H(t))·cos(δ)·sin(Φ)−sin(δ)·cos(Φ)],  (Equation 10)
and C(t) equals negative one if the present local time t is less than or equal to the solar noon time tSNor one if the present local time t is greater than the solar noon time tSN. The solar azimuth angle φScan also be expressed in terms independent of the solar elevation angle θS, i.e.,
φS(t)=tan−1[−sin(H(t))·cos(δ)/Y(t)],  (Equation 11)
where
Y(t)=[ sin(δ)·cos(Φ)−cos(δ)·sin(Φ)·cos(H(t))].  (Equation 12)
Thus, the solar elevation angle θSand the solar azimuth angle φSare functions of the local longitude λ and latitude Φ and the present local time t and date (i.e., the present day-number NDAY). Using Equations 1 and 2, the sunlight penetration distance can be expressed in terms of the height hWINof the window166, the height hWORKof the table168, the solar elevation angle θS, and the solar solar azimuth angle φS.

According to the first embodiment of the present invention, the motorized roller shades120are controlled such that the sunlight penetration distance dPENis limited to less than a desired maximum sunlight penetration distance dMAXduring all times of the day. For example, the sunlight penetration distance dPENmay be limited such that the sunlight does not shine directly on the table168to prevent sun glare on the table. The desired maximum sunlight penetration distance dMAXmay be entered, for example, using the GUI software of the PC, and may be stored in the memory in the controller150. In addition, the user may also use the GUI software of the computer to enter the local longitude λ and latitude Φ of the building, the façade angle φFfor each façade164of the building, and other related programming information, which may also be stored in the memory of each controller150.

In order to minimize distractions to an occupant of the space160(i.e., due to movements of the motorized roller shades), the controller150controls the motorized roller shades120to ensure that at least a minimum time period TMINexists between any two consecutive movements of the motorized roller shades. The minimum time period TMINthat may exist between any two consecutive movements of the motorized roller shades may be entered using the GUI software of the computer and may be also stored in the memory in the controller150. The user may select different values for the desired maximum sunlight penetration distance dMAXand the minimum time period TMINbetween shade movements for different areas and different groups of motorized roller shades120in the building.

FIG. 4is a simplified flowchart of a timeclock configuration procedure200executed periodically by the controller150of the load control system100to generate a shade timeclock schedule defining the desired operation of the motorized roller shades120of each of the façades164of the building according to the first embodiment of the present invention. For example, the timeclock configuration procedure200may be executed once each day at midnight to generate a new shade timeclock schedule for one or more areas in the building. The shade timeclock schedule is executed between a start time tSTARTand an end time tENDof the present day. During the timeclock configuration procedure200, the controller150first performs an optimal shade position procedure300for determining optimal shade positions POPT(t) of the motorized roller shades120in response to the desired maximum sunlight penetration distance dMAXfor each minute between the start time tSTARTand the end time tENDof the present day. The controller150then executes a timeclock event creation procedure400to generate the events of the shade timeclock schedule in response to the optimal shade positions POPT(t) and the user-selected minimum time period TMINbetween shade movements. The events times of the shade timeclock schedule are spaced apart by multiples of the user-specified minimum time period TMINbetween shade movements. Since the user may select different values for the desired maximum sunlight penetration distance dMAXand the minimum time period TMINbetween shade movements for different areas and different groups of motorized roller shades120in the building, a different shade timeclock schedule may be created and executed for the different areas and different groups of motorized roller shades in the building (i.e., the different façades164of the building).

The shade timeclock schedule is split up into a number of consecutive time intervals, each having a length equal to the minimum time period TMINbetween shade movements. The controller150considers each time interval and determines a position to which the motorized roller shades120should be controlled in order to prevent the sunlight penetration distance dPENfrom exceeding the desired maximum sunlight penetration distance dMAXduring the respective time interval. The controller150creates events in the shade timeclock schedule, each having an event time equal to beginning of respective time interval and a corresponding position equal to the position to which the motorized roller shades104should be controlled in order to prevent the sunlight penetration distance dPENfrom exceeding the desired maximum sunlight penetration distance dMAX. However, the controller150will not create a timeclock event when the determined position of a specific time interval is equal to the determined position of a preceding time interval (as will be described in greater detail below). Therefore, the event times of the shade timeclock schedule are spaced apart by multiples of the user-specified minimum time period TMINbetween shade movements.

FIG. 5is a simplified flowchart of the optimal shade position procedure300, which is executed by the controller150to generate the optimal shade positions POPT(t) for each minute between the start time tSTARTand the end time tENDof the shade timeclock schedule such that the sunlight penetration distance dPENwill not exceed the desired maximum sunlight penetration distance dMAX. The controller150first retrieves the start time tSTARTand the end time tENDof the shade timeclock schedule for the present day at step310. For example, the controller150could use the astronomical timeclock to set the start time tSTARTequal to the sunrise time tSUNRISEfor the present day, and the end time tENDequal to the sunset time tSUNSETfor the present day. Alternatively, the start and end times tSTART, tENDcould be set to arbitrary times, e.g., 6 A.M. and 6 P.M, respectively.

Next, the controller150sets a variable time tVARequal to the start time tSTARTat step312and determines a worst case façade angle φF-WCat the variable time tVARto use when calculating the optimal shade position POPT(t) at the variable time tVAR. Specifically, if the solar azimuth angle φSis within a façade angle tolerance φTOL(e.g., approximately 3°) of the fixed façade angle φFat step314(i.e., if φF−φTOL≦φS≦φF+φTOL), the controller150sets the worst case façade angle φF-WCequal to the solar azimuth angle φSof the façade164at step315. If the solar azimuth angle φSis not within the façade angle tolerance φTOLof the façade angle φFat step314, the controller150then determines if the façade angle φFplus the façade angle tolerance φTOLis closer to the solar azimuth angle φSthan the façade angle φFminus the façade angle tolerance φTOLat step318. If so, the controller150sets the worst case façade angle φF-WCequal to the façade angle φFplus the façade angle tolerance φTOLat step320. If the façade angle φFplus the façade angle tolerance φTOLis not closer to the solar azimuth angle φSthan the façade angle φFminus the façade angle tolerance φTOLat step318, the controller150sets the worst case façade angle φF-WCequal to the façade angle φFminus the façade angle tolerance φTOLat step322.

At step324, the controller150uses Equations 1-12 shown above and the worst case façade angle φF-WCto calculate the optimal shade position POPT(tVAR) that is required in order to limit the sunlight penetration distance dPENto the desired maximum sunlight penetration distance dMAXat the variable time tVAR. At step326, the controller150stores in the memory the optimal shade position POPT(tVAR) determined in step324. If the variable time tVARis not equal to the end time tENDat step328, the controller150increments the variable time tVARby one minute at step330and determines the worst case façade angle φF-WCand the optimal shade position POPT(tVAR) for the new variable time tVARat step324. When the variable time tVARis equal to the end time tENDat step328, the optimal shade position procedure300exits.

Thus, the controller150generates the optimal shade positions POPT(t) between the start time tSTARTand the end time tENDof the shade timeclock schedule using the optimal shade position procedure300.FIG. 6Ashows an example plot of optimal shade positions POPT1(t) of the motorized roller shades120on the west façade of the building on January 1, where the building is located at a longitude λ of approximately 75° W and a latitude Φ of approximately 40° N.FIG. 6Bshows an example plot of optimal shade positions POPT2(t) of the motorized roller shades120on the north façade of the building on June 1.FIG. 6Cshows an example plot of optimal shade positions POPT3(t) of the motorized roller shades120on the south façade of the building on April 1.

FIG. 7is a simplified flowchart of the timeclock event creation procedure400, which is executed by the controller150in order to generate the events of the shade timeclock schedule according to the first embodiment of the present invention. Since the shade timeclock schedule is split up into a number of consecutive time intervals, the timeclock events of the timeclock schedule are spaced between the start time tSTARTand the end time tENDby multiples of the minimum time period TMINbetween shade movements, which is selected by the user. During the timeclock event creation procedure400, the controller150generates controlled shade positions PCNTL(t), which comprise a number of discrete events, i.e., step changes in the position of the motorized roller shades at the specific event times. The controller150uses the controlled shade positions PCNTL(t) to adjust the position of the motorized roller shades during execution of the shade timeclock schedule. The resulting timeclock schedule includes a number of events, which are each characterized by an event time and a corresponding preset shade position.

The controller150uses the controlled shade positions PCNTL(t) to adjust the position of the motorized roller shades120during execution of a timeclock execution procedure900, which will be described in greater detail below with reference toFIG. 13. The timeclock execution procedure900is executed by the controller150periodically (e.g., once every minute) between the start time tSTARTand the end time tENDwhen the shade timeclock schedule is enabled. The shade timeclock schedule may be disabled, such that the timeclock execution procedure900is not executed periodically, when the space160is unoccupied or when the controller150receives an immediate demand command via the network communication link156. At the end of the shade timeclock schedule (i.e., at the end time tEND), the controller150controls the position of the motorized roller shades120to a nighttime position PNIGHT(e.g., the fully-closed position PFC) as will be described in greater detail below with reference toFIG. 13.

FIG. 8Ashows an example plot of controlled shade positions PCNTL1(t) of the motorized roller shades120on the west façade of the building on January 1 according to the first embodiment of the present invention.FIG. 8Bshows an example plot of controlled shade positions PCNTL2(t) of the motorized roller shades120on the north façade of the building on June 1 according to the first embodiment of the present invention.FIG. 8Cshows an example plot of controlled shade positions PCNTL3(t) of the motorized roller shades120on the south façade of the building on April 1 according to the first embodiment of the present invention.

The controller150examines the values of the optimal shade positions POPT(t) during each of the time intervals of the shade timeclock schedule (i.e., the time periods between two consecutive timeclock events) to determine a lowest shade position PLOWduring each of the time intervals. During the timeclock event creation procedure400, the controller150uses two variable times tV1, tV2to define the endpoints of the time interval that the controller is presently examining The controller150uses the variable times tV1, tV2to sequentially step through the events of the shade timeclock schedule, which are spaced apart by the minimum time period TMINaccording to the first embodiment of the present invention. The lowest shade positions PLOWduring the respective time intervals becomes the controlled shade positions PCNTL(t) of the timeclock events, which have event times equal to the beginning of the respective time interval (i.e., the first variable time tV1).

Referring toFIG. 7, the controller150sets the first variable time tV1equal to the start time tSTARTof the shade timeclock schedule at step410. The controller150also initializes a previous shade position PPREVto the nighttime position PNIGHTat step610. If there is enough time left before the end time tENDfor the present timeclock event (i.e., if the first variable time tV1plus the minimum time period TMINis not greater than the end time tEND) at step412, the controller150determines at step414if there is enough time for another timeclock event in the shade timeclock schedule after the present timeclock event. If the first variable time tV1plus two times the minimum time period TMINis not greater than the end time tENDat step414, the controller150sets the second variable time tV2equal to the first variable time tV1plus the minimum time period TMINat step416, such that the controller150will then examine the time interval between the first and second variable times tV1, tV2. If the first variable time tV1plus two times the minimum time period TMINis greater than the end time tENDat step414, the controller150sets the second variable time tV2equal to the end time tENDat step418, such that the controller150will then examine the time interval between the first variable time tV1and the end time tEND.

At step420, the controller150determines the lowest shade position PLOWof the optimal shade positions POPT(t) during the present time interval (i.e., between the first variable time tV1and the second variable time tV2determined at steps416and418). If, at step422, the previous shade position PPREVis not equal to the lowest shade position PLOWduring the present time interval (as determined at step420), the controller150sets the controlled shade position PCNTL(tV1) at the first variable time tV1to be equal to the lowest shade position PLOWof the optimal shade positions POPT(t) during the present time interval at step424. The controller150then stores in memory a timeclock event having the event time tV1and the corresponding controlled position PCNTL(tV1) at step426and sets the previous shade position PPREVequal to the new controlled position PCNTL(tV1) at step428. If, at step422, the previous shade position PPREVis equal to the lowest shade position PLOWduring the present time interval, the controller150does not create a timeclock event at the first variable time tV1. The controller150then begins to examine the next time interval by setting the first variable time tV1equal to the second variable time tV2at step430. The timeclock event creation procedure400loops around such that the controller150determines if there is enough time left before the end time tENDfor the present timeclock event at step412. If the first variable time tV1plus the minimum time period TMINis greater than the end time tENDat step412, the controller enables the shade timeclock schedule at step432and the timeclock event creation procedure400exits.

FIG. 9is a simplified flowchart of a daylighting procedure500, which is executed periodically by the controller150(e.g., once every second) when daylighting (i.e., control of the lighting loads112in response to the ambient light intensity LAMBmeasured by the daylight sensor154) is enabled at step510. When daylighting is not enabled at step510, the daylighting procedure500simply exits. When daylighting is enabled at step510, the controller150causes the daylight sensor154to measure the ambient light intensity LAMBat step512. If the measured ambient light intensity LAMBis less than a setpoint (i.e., target) intensity LSETat step514, the controller150controls the lighting control device110to increase the present lighting intensity LPRESof each of the lighting loads112by a predetermined value ΔLSET(e.g., approximately 1%) at step516and the daylighting procedure500exits. If the measured ambient light intensity LAMBis greater than the setpoint intensity LSETat step518, the controller150decreases the present lighting intensity LPRESof each of the lighting loads112by the predetermined value ΔLSETat step520and the daylighting procedure500exits. If the measured ambient light intensity LAMBis not less than the setpoint intensity LSETat step514and is not greater than the setpoint intensity LSETat step518(i.e., the ambient light intensity LAMBis equal to the setpoint intensity LSET), the daylighting procedure500simply exits without adjusting the present lighting intensity LPRESof each of the lighting loads112.

FIG. 10Ais a simplified flowchart of a demand response message procedure600, which is executed by the controller150in response to receiving an immediate demand response command via the network communication link156at step610. Whenever an immediate demand response command is received at step610, the controller150simply enables a demand response (DR) mode at step612, before the demand response message procedure600exits.

FIG. 10Bis a simplified flowchart of a load control procedure650, which is executed by the controller150periodically, e.g., every minute. If the demand response mode is not enabled at step652, the controller150executes a normal control procedure700for controlling the lighting control devices110, the motorized roller shades120, the temperature control devices130, and the controllable electrical receptacles140during a normal mode of operation, e.g., to maximize the comfort of the occupants of the spaces160of the building. On the other hand, if the demand response mode is enabled at step652(i.e., in response to receiving an immediate demand response command during the demand response message procedure600), the controller150executes a demand response control procedure800for controlling the lighting control devices110, the motorized roller shades120, the temperature control devices130, and the controllable electrical receptacles140to decrease the energy consumption of the load control system100, while maintaining the comfort of the occupants of the spaces160of the building at acceptable levels. During the normal control procedure700and the demand response command procedure800, the controller150controls the lighting control devices110, the motorized roller shades120, the temperature control devices130, and the controllable electrical receptacles140in the different spaces160(or areas) of the building on an area-by-area basis. For example, the controller150may control the lighting control devices110, the motorized roller shades120, the temperature control device130, and the controllable electrical receptacles140in a specific area differently depending upon whether the area is occupied or not.

FIG. 11is a simplified flowchart of the normal control procedure700executed periodically by the controller150when the controller is operating in the normal mode of operation (i.e., every minute). If the area is occupied at step710, the controller150transmits at step712one or more digital messages to the lighting control devices110so as to adjust the intensities of the lighting loads112to the user-specified desired lighting intensity levels LDES(e.g., as determined in response to actuations of the first set of buttons114of the lighting control devices110). At step714, the controller150transmits digital messages to the controllable electrical receptacles140to supply power to all of the plug-in electrical loads142in the area. Next, the controller150transmits a digital message to the temperature control device130at step715to control the setpoint temperature TSETto the user-specified desired temperature TDES(e.g., as determined in response to actuations of the raise and lower temperature buttons136,138of the temperature control device130). Finally, the controller150enables the shade timeclock schedule (as created during the timeclock event creation procedure400) at step716, and the normal control procedure700exits. Accordingly, shortly after the normal control procedure700exits, the timeclock execution procedure900will be executed in order to adjust the positions of the motorized roller shades120to the controlled positions PCNTL(t) determined in the timeclock event creation procedure400. In addition, the timeclock execution procedure900will be executed periodically until the shade timeclock schedule is disabled.

If the area is unoccupied at step710, the controller150turns off the lighting load112in the area at step718and turns off designated (i.e., some) plug-in electrical loads142at step720. For example, the designated plug-in electrical loads142that are turned off in step720may comprise table lamps, floor lamps, printers, fax machines, water heaters, water coolers, and coffee makers. However, other non-designated plug-in electrical loads142are not turned off in step720, such as, personal computers, which remain powered even when the area is unoccupied. If the HVAC system132is presently cooling the building at step722, the controller150increases the setpoint temperature TSETof the temperature control device130by a predetermined increment ΔTNRM—COOL(e.g., approximately 2° F.) at step724, such that the setpoint temperature TSETis controlled to a new setpoint temperature TNEW, i.e.,
TNEW=TSET+ΔTNRM—COOL.  (Equation 13)
The HVAC system132thus consumes less power when the area is unoccupied and the setpoint temperature TSETis increased to the new setpoint temperature TNEW.

The controller150then transmits digital messages to the electronic drive units126of the motorized roller shades120to move all of the shade fabrics122to the fully-closed positions at step726. The controller150also disables the shade timeclock schedule at step726, before the normal control procedure700exits. Since the shade fabrics122will be completely covering the windows, the shade fabrics will block daylight from entering the building and thus the shade fabrics prevent daylight from heating the building. Accordingly, the HVAC system132will consume less power when the motorized roller shades120are closed.

If the HVAC system132is presently heating the building at step722, the controller150decreases the setpoint temperature TSETof the temperature control device130by a predetermined increment ΔTNRM—HEAT(e.g., approximately 2° F.) at step728, such that the setpoint temperature TSETis controlled to the new setpoint temperature TNEW, i.e.,
TNEW=TSET−ΔTNRM—HEAT.  (Equation 14)
Thus, the HVAC system132consumes less power when the area is unoccupied and the setpoint temperature TSETis decreased to the new setpoint temperature TNEWduring the winter months.

Before adjusting the positions of the motorized roller shades120, the controller150first determines at step730if the façade164of the windows in the area may be receiving direct sunlight, e.g., using the Equations 1-12 shown above. If the façade164of the area is not receiving direct sunlight at step730, the controller150causes the electronic drive units126of the motorized roller shades120to move all of the shade fabrics122to the fully-closed positions and disables the shade timeclock schedule at step732, such that the shade fabrics provide additional insulation for the building. Accordingly, the shade fabrics122will prevent some heat loss leaving the building and the HVAC system132may consume less power. However, if the façade164of the area may be receiving direct sunlight at step730, the controller150controls the motorized roller shade120to the fully-open positions disables the shade timeclock schedule at step734in order to take advantage of the potential heat gain through the windows due to the direct sunlight. Rather than using the Equations 1-12 shown above to calculate whether the window may or may not be receiving direct sunlight, the load control system100may alternatively comprise one or more photosensors mounted adjacent the windows in the space to determine if the window is receiving direct sunlight.

FIGS. 12A and 12Bare simplified flowcharts of the demand response control procedure800executed periodically by the controller150when the controller is operating in the demand response mode of operation (i.e., once every minute after a demand response command is received). If the area is not occupied at step810, the controller150turns off the lighting loads112in the area at step812and turns off the designated plug-in electrical loads142at step814. If the HVAC system132is presently cooling the building at step816, the controller150increases the setpoint temperature TSETof each of the temperature control devices130by a predetermined increment ΔTDR—COOL1(e.g., approximately 3° F.) at step818. The controller150then controls the motorized roller shades120to the fully-closed positions and disables the shade timeclock schedule at step820, such that the HVAC system132will consume less power.

If the HVAC system132is presently heating the building at step816, the controller150decreases the setpoint temperatures TSETof each of the temperature control devices130by a predetermined increment ΔTDR—HEAT1(e.g., approximately 3° F.) at step822. If the façade164of the area is not receiving direct sunlight at step824, the controller150moves all of the motorized roller shades120to the fully-closed positions to provide additional insulation for the building and disables the shade timeclock schedule at step826, such that the HVAC system132will consume less power. If the façade164of the area may be receiving direct sunlight at step824, the controller150controls the motorized roller shade120to the fully-open positions at step828in order to take advantage of the potential heat gain through the windows due to the direct sunlight. The controller150also disables the shade timeclock schedule at step828, before the demand response control procedure800exits.

Referring toFIG. 12B, if the area is occupied at step810, the controller150transmits at step830one or more digital messages to the lighting control devices110to lower the present lighting intensities LPRESof each of the lighting loads112by a predetermined percentage ΔLDR(e.g., by approximately 20% of the present lighting intensity LPRES). The lighting control device110fades the present lighting intensity LPRESof each of the lighting loads112over a first fade time period (e.g., approximately thirty seconds) to a new lighting intensity LNEW, i.e.,
LNEW=ΔLDR·LPRES.  (Equation 15)
Accordingly, when operating at the new reduced lighting intensities LNEW, the lighting loads112consume less power. Alternatively, the controller150may decrease the setpoint light intensity LSETof the space160by a predetermined percentage ΔLSET-DRat step830.

Next, the controller150turns off the designated plug-in electrical loads142at step832. If the HVAC system132is presently cooling the building at step834, the controller150increases the setpoint temperatures TSETof each of the temperature control devices130by a predetermined increment ΔTDR—COOL2(e.g., approximately 2° F.) at step836. If the façade164of the area may be receiving direct sunlight at step838, the controller150controls the motorized roller shade120to the fully-closed positions at step840in order to reduce heat rise in the area. If the façade164of the area is not receiving direct sunlight at step838, the controller150enables the shade timeclock schedule at step842, such that the timeclock execution procedure900will be executed periodically to adjust the positions of the motorized roller shades120to the controlled positions PCNTL(t) after the demand response control procedure800exits.

If the HVAC system132is presently heating the building at step834, the controller150decreases the setpoint temperatures TSETof each of the temperature control devices130by a predetermined increment ΔTDR—HEAT2(e.g., approximately 2° F.) at step844. If the façade164of the area is not receiving direct sunlight at step846, the controller150enables the shade timeclock schedule at step848, such that the timeclock execution procedure900will be executed to control the positions of the motorized roller shades120to the controlled positions PCNTL(t) after the demand response control procedure800exits. The controller150then enables daylighting monitoring (DM) at step850by initializing a daylighting monitoring (DM) timer (e.g., to approximately one minute) and starting the timer decreasing in value with respect to time. When the daylighting monitoring timer expires, the controller150will execute a daylighting monitoring (DM) procedure1000if the daylighting procedure500(as shown inFIG. 9) is causing the load control system100to save energy. Specifically, the controller150determines if providing daylight in the area by controlling the motorized roller shades120to the controlled positions PCNTL(t) of the timeclock schedule has resulted in energy savings in the amount of energy consumed by the lighting loads112(as compared to the energy consumed by the lighting loads when the motorized roller shades are fully closed). The daylighting monitoring timer is initialized to an amount of time that is appropriate to allow the lighting control devices110to adjust the intensities of the lighting loads112in response to the ambient light intensity LAMBmeasured by the daylight sensor154. The daylighting monitoring procedure1000will be described in greater detail below with reference toFIG. 14.

If the façade164of the area may be receiving direct sunlight at step846, the controller150executes a modified schedule procedure1100(which will be described in greater detail below with reference toFIG. 15A) to temporarily increase the desired maximum sunlight penetration distance dMAXby a predetermined amount ΔdMAX(e.g., by approximately 50%) and to generate a modified timeclock schedule at the modified maximum sunlight penetration distance dMAX. The controller150then enables the shade timeclock schedule at step852, such that the controller will adjust the positions of the motorized roller shades120to the modified controlled positions PCNTL(t) as determined during the modified schedule procedure1100when the timeclock execution procedure900is executed after the demand response control procedure800exits. Since the desired maximum sunlight penetration dMAXhas been increased, the sunlight will penetrate deeper into the space160using the modified controlled positions PCNTL(t) determined during the modified schedule procedure1100.

Referring back toFIG. 12B, after executing the modified schedule procedure1100, the controller150enables HVAC monitoring at step854by initializing an HVAC monitoring timer (e.g., to approximately one hour) and starting the timer decreasing in value with respect to time. When the HVAC monitoring timer expires, the controller150will execute an HVAC monitoring procedure1150to determine if the modified controlled positions PCNTL(t) of the motorized roller shades120have resulted in energy savings in the amount of energy consumed by the HVAC system132. The HVAC monitoring procedure1150will be described in greater detail below with reference toFIG. 15B. After enabling HVAC monitoring at step854, the demand response control procedure800exits.

As previously mentioned, the load control procedure650is executed periodically by the controller150. During the first execution of the load control procedure650after a change in state of the load control system100(e.g., in response to receiving a demand response command, detecting an occupancy or vacancy condition, or determining that one of the façades164may be receiving direct sunlight or not), the controller150is operable to lower the lighting intensities of the lighting loads112by the predetermined percentage ΔLDR(e.g., at step830) or to adjust the setpoint temperatures TSETof the temperature control devices130by predetermined amounts (e.g., at steps724,728,818,822,836,844). However, during subsequent executions of the load control procedure650, the controller150does not continue lowering the lighting intensity of the lighting loads112by the predetermined percentage ΔLDR(at step830), or adjusting the setpoint temperatures TSETby predetermined amounts (at steps724,728,818,822,836,844). In addition, the controller150only executes the modified schedule procedure1100and enables daylighting monitoring (at step850) or HVAC monitoring (at step854) the first time that the load control procedure650is executed after a change in state of the load control system100.

FIG. 13is a simplified flowchart of the timeclock execution procedure900, which is executed by the controller150periodically, i.e., every minute between the start time tSTARTand the end time tENDof the shade timeclock schedule. Since there may be multiple timeclock schedules for the motorized roller shades120, the controller150may execute the timeclock execution procedure900multiple times, e.g., once for each shade timeclock schedule. During the timeclock execution procedure900, the controller150adjusts the positions of the motorized roller shades120to the controlled positions PCNTL(t) determined in the timeclock event creation procedure400(or alternatively the modified controlled positions PCNTL(t) determined in the modified schedule procedure1100).

In some cases, when the controller150controls the motorized roller shades120to the fully-open positions PFO(i.e., when there is no direct sunlight incident on the façade164), the amount of daylight entering the space160(e.g., due to sky luminance from light reflected off of clouds or other objects) may be unacceptable to a user of the space. Therefore, the controller150is operable to have a visor position PVISORenabled for one or more of the spaces160or façades164of the building. The visor position PVISORdefines the highest position to which the motorized roller shades120will be controlled during the shade timeclock schedule. The visor position PVISORis typically lower than the fully-open position PFO, but may be equal to the fully-open position. The position of the visor position PVISORmay be entered using the GUI software of the PC. In addition, the visor position PVISORmay be enabled and disabled for each of the spaces160or façades164of the building using the GUI software of the PC.

Referring toFIG. 13, if the timeclock schedule is enabled at step910, the controller150determines the time tNEXTof the next timeclock event from the shade timeclock schedule at step912. If the present time tPRES(e.g., determined from the astronomical timeclock) is equal to the next event time tNEXTat step914and the controlled position PCNTL(tNEXT) at the next event time tNEXTis greater than or equal to the visor position PVISORat step916, the controller150sets a new shade position PNEWequal to the visor position PVISORat step918. If the controlled position PCNTL(tNEXT) at the next event time tNEXTis less than the visor position PVISORat step916, the controller150sets the new shade position PNEWequal to the controlled position PCNTL(tNEXT) at the next event time tNEXTat step920. If the present time tPRESis not equal to the next event time tNEXTat step914, the controller150determines the time tPREVof the previous timeclock event from the shade timeclock schedule at step922and sets the new shade position PNEWequal to the controlled position PCNTL(tPREV) at the previous event time tPREVat step924.

After setting the new shade position PNEWat steps918,920,924, the controller150makes a determination as to whether the present time is equal to the end time tENDof the shade timeclock schedule at step926. If the present time tPRESis equal to the end time tENDat step926, the controller150sets the new shade position PNEWto be equal to the nighttime position PNIGHTat step928and disables the timeclock schedule at step930. If the new shade position PNEWis the same as the present shade position PPRESof the motorized roller shades120at step932, the timeclock execution procedure900simply exits without adjusting the positions of the motorized roller shades120. However, if the new shade position PNEWis not equal to the present shade position PPRESof the motorized roller shades120at step932, the controller150adjusts the positions of the motorized roller shades120to the new shade position PNEWat step934and the timeclock execution procedure900exits.

FIG. 14is a simplified flowchart of the daylighting monitoring procedure1000, which is executed by the controller150when the daylighting monitoring timer expires at step1010. As previously mentioned, the daylighting monitoring timer is initialized to an amount of time that is appropriate to allow the lighting control devices110to adjust the intensities of the lighting loads112in response to the ambient light intensity LAMBdetermined by the daylight sensor154. During the daylighting monitoring procedure1000, the controller150first determines at step1012the present intensities of the lighting loads110in the area, which are representative of the amount of power presently being consumed by the lighting loads. The controller150compares these lighting intensities to the lighting intensities of the lighting loads112that would be required if the motorized roller shades120were at the fully-closed positions to determine if the load control system100is presently saving energy as compared to when the motorized roller shades120are fully closed. If the load control system100is presently saving energy at step1014, the controller150maintains the present positions of the motorized roller shades120and the daylighting monitoring procedure1000simply exits. However, if the load control system100is not presently saving energy at step1014, the controller150closes all of the motorized roller shades120in the area to reduce heat loss at step1016, before the daylighting monitoring procedure1000exits.

FIG. 15Ais a simplified flowchart of the modified schedule procedure1100, which is executed by the controller150during the demand response control procedure800when the area is occupied, the HVAC system132is presently heating the building, and there may be direct sunlight shining on the façade164. First, the controller150temporarily increases the desired maximum sunlight penetration distance dMAXby a predetermined percentage ΔdMAX(e.g., by approximately 50%) at step1110, e.g.,
dMAX=(1+ΔdMAX)·dMAX.  (Equation 16)
Next, the controller150executes the optimal shade position procedure300(as shown inFIG. 5) for determining the optimal shade positions POPT(t) of the motorized roller shades120in response to the modified desired maximum sunlight penetration distance dMAX. The controller150then executes the timeclock event creation procedure400to generate the modified controlled positions PCNTL(t) in response to the optimal shade positions POPT(t) determined from the modified desired maximum sunlight penetration distance dMAX. Finally, the modified schedule procedure1100exits.

FIG. 15Bis a simplified flowchart of the HVAC monitoring procedure1150, which is executed by the controller150when the HVAC monitoring timer expires at step1160. The controller150first determines energy usage information from the HVAC system132. For example, the controller150could cause the temperature control device130to transmit a request for energy usage information from the HVAC system132via the HVAC communication link134. Alternatively, the temperature control device130could store data representative of the energy usage information of the HVAC system132. For example, the temperature control device130could monitor when the HVAC system132is active or inactive while operating to heat the building when HVAC monitoring in enabled and determine a heating duty cycle, which is representative of the energy usage information of the HVAC system132. Alternatively, the temperature control device130could monitor the rate at which the temperature in the space160decreases when the HVAC system is not actively heating the space.

Referring back toFIG. 15B, the controller150determines if the HVAC system132is saving energy during the HVAC monitoring at step1164. For example, the controller150could compare the heating duty cycle during HVAC monitoring to the heating duty cycle prior to HVAC monitoring to determine if the HVAC system132is saving energy. If the heating duty cycle during HVAC monitoring is less than the heating duty cycle prior to HVAC monitoring than the HVAC system is saving energy. Alternatively, the controller150could compare the rate at which the present temperature TPRESof the space160decreases when the HVAC system132is not actively heating the space during HVAC monitoring to the rate prior to HVAC monitoring to determine if the HVAC system is saving energy. If the rate at which the present temperature TPRESof the space160decreases when the HVAC system132is not actively heating the space160is less than the rate prior to HVAC monitoring, the HVAC system is saving energy. If the controller150determines that the HVAC system132is saving energy at step1164, the controller150maintains the present positions of the motorized roller shades120and the HVAC monitoring procedure1150simply exits. However, if the HVAC system132is not presently saving energy at step1164, the controller150closes all of the motorized roller shades120in the area to reduce heat loss at step1166, before the HVAC monitoring procedure1150exits. Alternatively, the HVAC monitoring procedure1150could be executed by the temperature control device130.

FIG. 16is a simplified flowchart of a planned demand response procedure1200executed by the controller150of the load control system100according to a second embodiment of the present invention. In response to receiving a planned demand response command, the controller150controls the load control system100to reduce the total power consumption at a predetermined start time tSTARTin the future, for example, at noon on the day after the planned demand response command was received. The controller150is operable to “pre-condition” (i.e., pre-cool or pre-heat) the building before the start time tSTARTof the planned demand response command, such that the HVAC system132will be able to consume less power during the planned demand response event (i.e., after the start time). To pre-condition the building before a planned demand response event, the controller150is operable to pre-cool the building when the HVAC system132is in the cooling mode and will be cooling the building during the present day (e.g., during the summer), and to pre-heat the building when the HVAC system is in heating mode and the will be heating the building during the present day (e.g., during the winter).

Referring toFIG. 16, the planned demand response procedure1200is executed by the controller150when a planned demand response command is received via the network communication link156at step1210. The controller150first determines if the present time of the day is before the predetermined pre-condition time tPRE(e.g., approximately 6 A.M.) at step1212. If so, the controller150enables a pre-condition timeclock event at step1214. The controller150will then execute (in the future at the pre-condition time tPRE) a pre-condition timeclock event procedure1300, which will be described in greater detail below with reference toFIG. 17. If the present time of the day is after the pre-condition time tPREat step1212and the HVAC system132is presently cooling the building at step1216, the controller150decreases the setpoint temperatures TSETof each of the temperature control devices130in the building by a pre-cool temperature increment ΔTPRE-COOL(e.g., approximately 4° F.) at step1218in order to pre-condition the building before the planned demand response event. Specifically, the setpoint temperature TSETof the building is lowered from an initial temperature TINITto a new temperature TNEWto pre-cool the building in preparation for the planned demand response event during which the setpoint temperature will be increased above the initial temperature TINIT(as will be described in greater detail below with reference toFIG. 18).

Referring back toFIG. 16, if the HVAC system132is presently heating the building at step1216, the controller150increases the setpoint temperatures TSETof each of the temperature control devices130in the building by a pre-heat temperature increment ΔTPRE-HEAT(e.g., approximately 4° F.) at step1220. After either enabling the pre-condition timeclock event at step1214or pre-conditioning the building at step1218or step1220, the controller150enables a planned demand response timeclock event at step1222, before the planned demand response procedure1200exits. A planned demand response timeclock event procedure1400will be executed by the controller150at a planned demand response start time tSTART. The planned demand response timeclock event procedure1400will be described in greater detail below with reference toFIG. 18.

FIG. 17is a simplified flowchart of the pre-condition timeclock event procedure1300, which is executed by the controller150at step1310(i.e., at the pre-condition time tPRE). If the pre-condition timeclock event is not enabled at step1312, the pre-condition timeclock event procedure1300simply exits. However, if the pre-condition timeclock event is enabled at step1312and the HVAC system132is presently cooling the building at step1314, the controller150causes each of the temperature control devices130to decrease the setpoint temperatures TSETby the pre-cool temperature increment ΔTPRE-COOL(i.e., approximately 4° F.) at step1316in order to pre-cool the building before the planned demand response event, and the pre-condition timeclock event procedure1300exits. If the HVAC system132is presently heating the building at step1314, the controller150increases the setpoint temperatures TSETof each of the temperature control devices130by the pre-heat temperature increment ΔTPRE-HEAT(e.g., approximately 4° F.) at step1318in order to pre-heat the building before the planned demand response event, and the pre-condition timeclock event procedure1300exits.

FIG. 18is a simplified flowchart of the planned demand response timeclock event procedure1400, which is executed by the controller150at step1410(i.e., at the start time tSTART). If the planned demand response timeclock event is not enabled at step1412, the planned demand response timeclock event procedure1400simply exits. However, if the planned demand response timeclock event is enabled at step1412and the HVAC system132is presently cooling the building at step1414, the controller150causes each of the temperature control devices130to increase the respective setpoint temperature TSETby a temperature increment ΔTPLAN1(i.e., approximately 8° F.) at step1416, such that the new temperature TNEWis greater than the initial temperature TINITof the building before pre-cooling, i.e.,
TNEW=TINIT+(ΔTPLAN1−ΔTPRE-COOL).  (Equation 17)
At step1418, the controller150causes the lighting control devices110to lower each of the present lighting intensities LPRESof the lighting loads112by a predetermined percentage ΔLPLAN1(e.g., by approximately 20% of the present intensity), such that the lighting loads consume less power. At step1420, the controller150causes each of the motorized roller shades120to move the respective shade fabric122to the fully-closed position, before the planned demand response timeclock event procedure1400exits.

If the HVAC system132is presently heating the building at step1414, the controller150decreases the setpoint temperatures TSETof each of the temperature control devices130by a temperature increment ΔTPLAN2(i.e., approximately 8° F.) at step1422, such that the new temperature TNEWis less than the initial temperature TINITof the building before pre-heating, i.e.,
TNEW=TINIT−(ΔTPLAN2−ΔTPRE-HEAT).  (Equation 18)
At step1424, the controller150decreases each of the present lighting intensities LPRESof the lighting loads112connected to the lighting control devices110by a predetermined percentage ΔLPLAN2(e.g., by approximately 20% of the present intensity). At step1426, the controller150moves the respective shade fabric122of each of the motorized roller shades120to the fully-closed position, before the planned demand response timeclock event procedure1400exits.

While the controller150of the load control system100ofFIG. 1receives the demand response command from the electrical utility company via the network communication link156, the load control system could alternatively receive the demand response command through other means. Often, the electrical utility company may not be connected to the load control system100via the Internet (i.e., via the network communication link156). In such situations, a representative of the electrical utility company may contact a building manager of the building in which the load control system100is installed via telephone in order to communicate the specific demand response command. For example, the building manager could actuate one of the buttons114on the lighting control device110in order to input an immediate demand response command to the load control system100. The lighting control device110could then transmit appropriate digital messages to the controller150. Alternatively, the load control system100could also comprise a personal computer or laptop operable to communicate with the controller150. The building manager could use the personal computer to communicate an immediate or a planned demand response command to the controller150. Further, the controller150could include an antenna, such that the building manager could use a wireless cell phone or a wireless personal digital assistant (PDA) to transmit an immediate or a planned demand response command wirelessly to the controller (e.g., via RF signals).

According to a third embodiment of the present invention, the controller150is operable to control the lighting control device110, the motorized roller shades120, the temperature control device130, and the controllable electrical receptacle140according to a plurality of demand response (DR) levels. A demand response level is defined as a combination of predetermined parameters (e.g., lighting intensities, shades positions, temperatures, etc.) for one or more of the loads of the load control system100. The demand response levels provide a number of predetermined levels of energy savings that the load control system100may provide in response to the demand response command. For example, in a specific demand response level, a certain number of lighting loads may be dimmed by a predetermined amount, a certain number of motorized roller shades may be closed, a certain number of plug-in electrical loads142may be turned off, and the setpoint temperature may be adjusted by a certain amount. The demand response level to which the controller150controls the load control system100may be included in the demand response command received from the electrical utility company via the network communication link156. Alternatively, the demand response command received from the electrical utility company may not include a specific demand response level. Rather, the controller150may be operable to select the appropriate demand response level in response to the demand response command transmitted by the electrical utility company.

When the load control system100is programmed to provide multiple demand response levels, each successive demand response level further reduces the total power consumption of the load control system100. For example, the electrical utility company may first transmit a demand response command having demand response level one to provide a first level of energy savings, and then may subsequently transmit demand response commands having demand response levels two, three, and four to further and sequentially reduce the total power consumption of the load control system100. Four example demand response levels are provided in the following table, although additional demand response levels could be provided. As shown in Table 1, the second demand response level causes the load control system100to consume less power than the first demand response level, and so on.

FIGS. 19A and 19Bare simplified flowcharts of a demand response level procedure1500executed by the controller150according to the third embodiment of the present invention. The demand response level procedure1500is executed by the controller150in response to receiving a demand response command including a demand response level via the network communication link156at step1510. If the demand response level of the received demand response command is one at step1512, the controller150lowers the present intensities LPRESof only some of the lighting loads112, for example, only the lighting loads112in the non-working areas of the building (such as, for example, rest rooms, corridors, and public areas) by a first predetermined percentage ΔL1(e.g., approximately 20% of an initial lighting intensity LINIT) at step1514. The controller150then closes the motorized roller shades120in the same non-working areas of the building at step1516. If the HVAC system132is presently cooling the building at step1518, the controller150increases the setpoint temperatures TSETby a first temperature increment ΔT1(e.g., approximately 2° F.) at step1520, and the demand response level procedure1500exits. If the HVAC system132is presently heating the building at step1518, the controller150decreases the setpoint temperatures TSETby the first temperature increment ΔT1at step1522, and the demand response level procedure1500exits.

If the demand response level of the received demand response command is not one at step1512, but is two at step1524, the controller150lowers the present intensities LPRESof all of the lighting loads112in the building, i.e., including the working areas of the building (such as, office spaces and conference rooms) by the first predetermined percentage ΔL1(i.e., approximately 20% of the initial lighting intensity LINIT) at step1526. If the controller150had previously reduced the present intensities LPRESof the lighting loads112in the non-working areas of the building at step1514(i.e., according to the demand response level one), the controller only adjusts the present intensities LPRESof the lighting loads112in the working areas of the building at step1526. At step1528, the controller150then closes the motorized roller shades120in all of the areas of the building. If the HVAC system132is presently cooling the building at step1530, the controller150increases the setpoint temperature TSETby a second temperature increment ΔT2(e.g., approximately 4° F.) at step1532, and the demand response level procedure1500exits. If the controller150had previously increased the setpoint temperatures TSETby the first temperature increment ΔT1at step1520(i.e., according to the demand response level one), the controller150only increases the setpoint temperatures TSETby approximately 2° F. at step1532, (i.e., ΔT2−ΔT1). If the HVAC system132is presently heating the building at step1530, the controller150decreases the setpoint temperature TSETby the second temperature increment ΔT2at step1534, and the demand response level procedure1500exits.

Referring toFIG. 19B, if the demand response level is not two at step1524, but is three at step1536, the controller150lowers the present intensities LPRESof all of the lighting loads112in the building by a second predetermined percentage ΔL2(i.e., approximately 50% of the initial lighting intensity LINIT) at step1538. If the controller150had previously reduced the present intensities LPRESof the lighting loads112in any of the areas of the building at steps1514or1526(i.e., according to the demand response levels one or two), the controller only adjusts the present intensities LPRESof each of the lighting loads112by the necessary amount at step1538. The controller150then closes the motorized roller shades120in all of the areas of the building at step1540(if needed). If the HVAC system132is presently cooling the building at step1542, the controller150increases the setpoint temperature TSETby a third temperature increment ΔT3(e.g., approximately 6° F.) at step1544, and the demand response level procedure1500exits. If the HVAC system132is presently heating the building at step1542, the controller150decreases each of the setpoint temperatures TSETby the third temperature increment ΔT3at step1546, and the demand response level procedure1500exits.

If the demand response level is not three at step1536, but is four at step1548, the controller150lowers the present intensities LPRESof all of the lighting loads112in the building by the second predetermined percentage ΔL2at step1550(if needed) and closes all of the motorized roller shades120at step1552(if needed). At step1554, the controller150transmits digital messages to the electrical receptacles140to turn off the designated plug-in electrical loads142, such as, for example, table lamps, floor lamps, printers, fax machines, water heaters, water coolers, and coffee makers, but leaves some other plug-in loads powered, such as, personal computers. If the HVAC system132is presently cooling the building at step1556, the controller150turns off the HVAC system at step558, and the demand response level procedure1500exits. If the HVAC system132is presently heating the building at step1556, the controller150causes each of the temperature control devices130to decrease the respective setpoint temperature TSETto a minimum temperature TMINat step1560and the demand response level procedure1500exits.

FIG. 20is a simplified block diagram of a distributed load control system that may be installed in a building, such as a residence, according to a fourth embodiment of the present invention. The load control system1600comprises a lighting control device, e.g., a wall-mountable dimmer switch1610, which is coupled to an AC power source1602via a line voltage wiring1604. The dimmer switch1610is operable to adjust the amount of power delivered to the lighting load1612to thus control the present lighting intensity LPRESof the lighting load1612. The dimmer switch1610is also operable to fade the present lighting intensity LPRESbetween two lighting intensities. The dimmer switch1610comprises a control actuator1614for allowing a user to turn the lighting load1612on and off. The dimmer switch1610further comprises an intensity adjustment actuator1616for allowing the user to adjust the present lighting intensity LPRESof the lighting load1612between a minimum lighting intensity LMINand a maximum lighting intensity LMAX. An example of a wall-mountable dimmer switch is described in greater detail in previously-referenced U.S. Pat. No. 5,248,919.

The dimmer switch1610is operable to transmit and receive digital messages via wireless signals, e.g., RF signals1606(i.e., an RF communication link). The dimmer switch1610is operable to adjust the present lighting intensity LPRESof the lighting load1612in response to the digital messages received via the RF signals1606. The dimmer switch1610may also transmit feedback information regarding the amount of power being delivered to the lighting load1610via the digital messages included in the RF signals1606. Examples of RF lighting control systems are described in greater detail in commonly-assigned U.S. Pat. No. 5,905,442, issued on May 18, 1999, entitled METHOD AND APPARATUS FOR CONTROLLING AND DETERMINING THE STATUS OF ELECTRICAL DEVICES FROM REMOTE LOCATIONS, and U.S. patent application Ser. No. 12/033,223, filed Feb. 19, 2008, entitled COMMUNICATION PROTOCOL FOR A RADIO-FREQUENCY LOAD CONTROL SYSTEM, the entire disclosures of which are both hereby incorporated by reference.

The load control system1600comprises a motorized window treatment, e.g., a motorized roller shade1620, which may be positioned in front of a window for controlling the amount of daylight entering the building. The motorized roller shade1620comprises a flexible shade fabric1622rotatably supported by a roller tube1624, and an electronic drive unit (EDU)1626, which may be located inside the roller tube1624. The electronic drive unit1626may be powered by an external transformer (XFMR)1628, which is coupled to the AC power source1602and produces a lower voltage AC supply voltage for the electronic drive unit. The electronic drive unit1626is operable to transmit and receive the RF signals1606, such that the electronic drive unit may control the position of the shade fabric1622in response to digital messages received via the RF signals and may transmit feedback information regarding the position of the shade fabric via the RF signals.

The load control system1600also comprises a temperature control device1630, which is coupled to an HVAC system1632via an HVAC communication link1634, e.g., a digital communication link, such as an Ethernet link. The temperature control device1630measures the present temperature TPRESin the building and transmits appropriate digital messages to the HVAC system1632to thus control the present temperature TPRESin the building towards the setpoint temperature TSET. The temperature control device1630is operable to adjust the setpoint temperature TSETin response to the digital messages received via the RF signals1606. Alternatively, the HVAC communication link1634could comprise a more traditional analog control link for simply turning the HVAC system1632on and off.

FIG. 21Ais an enlarged front view of the temperature control device1630. The temperature control device1630comprises a temperature adjustment actuator1670(e.g., a rocker switch). Actuations of an upper portion1670A of the temperature adjustment actuator1670cause the temperature control device1630to increase the setpoint temperature TSET, while actuations of a lower portion1670B of the temperature adjustment actuator cause the temperature control device to decrease the setpoint temperature TSET. The temperature control device1630further comprises a room temperature visual display1672A and a setpoint temperature visual display1672B, which each comprise linear arrays of light-emitting diodes (LEDs) arranged parallel to each other as shown inFIG. 21A. One of the individual LEDs of the room temperature visual display1672A is illuminated to display the present temperature TPRESof the room in which the temperature control device1630is located, for example, on a linear scale between 60° F. and 80° F. In a similar manner, one of the individual LEDs of the setpoint temperature visual display1672B is illuminated to display the setpoint temperature TSETof the temperature control device1630. The temperature control device1630transmits digital messages to the other control devices of the load control system1600via the RF signals1606in response to actuations of an “eco-saver” actuator1674as will be described below. The temperature control device1630has a cover plate1676, which covers a plurality of operational actuators1678.FIG. 21Bis a front view of the temperature control device1630in which the cover plate1676is open and the operational actuators1678are shown. Actuations of the operational actuators1678adjust the operation of the HVAC system1632, for example, to change between the heating mode and the cooling mode.

Referring back toFIG. 20, the load control system1600may also comprise a wireless temperature sensor1636, which may be mounted remotely in a location away from the temperature control device1630and may also be battery-powered.FIG. 22is an enlarged perspective view of the wireless temperature sensor1636. The wireless temperature sensor1636comprises an internal temperature sensing device (not shown) for measuring the present temperature TPRESin the building at the location away from the temperature control device1630. The wireless temperature sensor1636comprises vents1680, which allow for air flow from the outside of the temperature sensor to the internal temperature sensing device inside the temperature sensor. The vents1680help to improve the accuracy of the measurement of the present temperature TPRESin the room in which the wireless temperature sensor1636is mounted (i.e., of the temperature outside the wireless temperature sensor). The wireless temperature sensor1636further comprises a link button1682and a test button1684for use during setup and configuration of the wireless temperature sensor. The wireless temperature sensor1636is operable to transmit digital messages regarding the measured temperature to the temperature control device1630via the RF signals1606. In response to receiving the RF signals1606from the wireless temperature sensor1636, the temperature control device is operable to update the room temperature visual display1672A to display the present temperature TPRESof the room at the location of the wireless temperature sensor and to control the HVAC system1632, so as to move the present temperature TPRESin the room towards the setpoint temperature TSET.

FIG. 23is a simplified block diagram of the temperature control device1630. The temperature control device1630comprises a controller1690, which may be implemented as, for example, a microprocessor, a microcontroller, a programmable logic device (PLD), an application specific integrated circuit (ASIC), or any suitable processing device. The controller1692is coupled to an HVAC communication circuit1692(e.g., a digital communication circuit, such as an Ethernet communication circuit), which is connected to the HVAC communication link1634to allow the controller to adjust the setpoint temperature TSETof the HVAC system1632. If the HVAC communication circuit1692comprises an analog control link, the HVAC communication circuit1692could simply comprise a switching device for enabling and disabling the HVAC system1632.

The controller1690is operable to determine the present temperature TPRESin the building in response to an internal temperature sensor1694. The controller1690is further coupled to a wireless communication circuit, e.g., an RF transceiver1695, which is coupled to an antenna1696for transmitting and receiving the RF signals1606. The controller1690is operable to determine the present temperature TPRESin the building in response to the RF signals1606received from the wireless temperature sensor1636. Alternatively, the temperature control device1630may simply comprise either one or the other of the internal temperature sensor1694and the RF transceiver1695for determining the present temperature TPRESin the room. Examples of antennas for wall-mounted control devices are described in greater detail in commonly-assigned U.S. Pat. No. 5,982,103, issued Nov. 9, 1999, and U.S. Pat. No. 7,362,285, issued Apr. 22, 2008, both entitled COMPACT RADIO FREQUENCY TRANSMITTING AND RECEIVING ANTENNA AND CONTROL DEVICE EMPLOYING SAME, the entire disclosures of which are hereby incorporated by reference.

The temperature control device1630further comprises to a memory1698for storage of the setpoint temperature TSETand the present temperature TPRESin the building, as well as data representative of the energy usage information of the HVAC system1632. The memory1698may be implemented as an external integrated circuit (IC) or as an internal circuit of the controller1690. The controller1690may be operable to determine the data representative of the energy usage information of the HVAC system1632in a similar manner as the temperature control device130of the first embodiment. For example, the data representative of the energy usage information of the HVAC system1632may comprise values of the duty cycle defining when the HVAC system is active and inactive during a predetermined time period, or the rate at which the present temperature TPRESdecreases or increases in the room when the HVAC system is not actively heating or cooling the space, respectively, during a predetermined time period.

A power supply1699receives power from the line voltage wiring1604and generates a DC supply voltage VCCfor powering the controller1690and other low-voltage circuitry of the temperature control device1630. The controller1690is coupled to the temperature adjustment actuator1670, the eco-saver actuator1674, and the operational actuators1678, such that the controller is operable to adjust the operation of the HVAC system1632in response to actuations of these actuators. The controller1690is coupled to the room temperature visual display1672A and the setpoint temperature visual display1672B for displaying the present temperature TPRESand the setpoint temperature TSET, respectively.

Referring back toFIG. 20, the load control system100further comprises one or more controllable electrical receptacles1640, and plug-in load control devices1642for control of plug-in electrical loads, such as, for example, a table lamp1644, a television1646, a floor lamp, a stereo, or a plug-in air conditioner. The controllable electrical receptacle1640and the plug-in load control device1642are responsive to the digital messages received via the RF signals1606to turn on and off the respective plug-in loads1644,1646. The plug-in load control device1642is adapted to be plugged into a standard electrical receptacle1648. The controllable electrical receptacle1640may comprise a dimmable electrical receptacle including an internal dimming circuit for adjusting the intensity of the lamp1644. Additionally, the load control system1600could comprise one or more controllable circuit breakers (not shown) for control of other switched electrical loads, such as, for example, a water heater. The load control system1600may also comprise additional dimmer switches1610, motorized roller shades1620, temperature control devices1630, controllable electrical receptacles1640, and plug-in load control devices1642.

According to the fourth embodiment of the present invention, the dimmer switch1610, the motorized roller shade1620, the temperature control device1630, and the controllable electrical receptacles1640,1642are each individually responsive to a plurality of demand response levels, i.e., predetermined energy-savings “presets”. The energy-savings presets may be user selectable and may be defined to provide energy savings for different occupancy conditions of the building. For example, the energy-savings presets may comprise a “normal” preset, an “eco-saver” preset, an “away” preset, a “vacation” preset, and a “demand response” preset. Examples of the energy-savings presets are provided in the following table.

When the normal preset is selected, the load control system1600operates as controlled by the occupant of the building, i.e., the normal preset provides no changes to the parameters of the load control system. For example, the lighting loads1612may be controlled to 100%, the motorized roller shades1620may be opened, and the setpoint temperature TSETmay be controlled to any temperature as determined by the occupant. The eco-saver preset provides some energy savings over the normal preset, but still provides a comfortable environment for the occupant. The away preset provides additional energy savings by turning off the lighting loads and some of the plug-in electrical loads when the occupant may be away temporarily away from the building. The vacation preset provides the maximum energy savings of the energy-savings presets shown in Table 2 for times when the occupant may be away from the building for an extended period of time.

The temperature control device1630is operable to increase or decrease the setpoint temperature TSETin response to the mode of the HVAC system1632(i.e., heating or cooling, respectively) as part of the energy-savings presets. The temperature control device1630may comprise a heating and cooling switch for changing between heating and cooling of the building. Alternatively, the temperature control device1630could, as part of the energy-savings presets, adjust the setpoint temperature TSETin response the present time of the year (i.e., the summer or the winter). For example, the lighting control device1610could comprise an astronomical time clock and may transmit digital messages including the present time of the year via the RF signals1606.

The load control system1600may also include a keypad1650to allow for manual selection of the energy-savings presets, specifically, the normal preset, the eco-saver preset, the away preset, and the vacation preset. The keypad1650comprises a plurality of preset buttons1652including, for example, a preset button1652for each of the energy-savings presets that may be selected by the keypad1650. The keypad1650transmits digital messages to the other control devices of the load control system1600via the RF signals1606in response to actuations of the preset buttons1652. The dimmer switch1610, the motorized roller shade1620, the temperature control device1630, the controllable electrical receptacles1640, and the plug-in load control device1642operate as shown in Table 2 in response to the specific energy-savings preset transmitted in the digital messages from the keypad1650. In addition, the eco-saver preset may be selected in response to an actuation of the eco-saver actuator1674on the temperature control device1630. Specifically, the controller1690of the temperature control device1630is operable to transmit a digital message including an eco-saver preset command via the RF transceiver1695in response to an actuation of the eco-saver actuator1674.

The load control system1600may also comprise a smart power meter1660coupled to the line voltage wiring1604. The smart power meter1660is operable to receive demand response commands from the electrical utility company, for example, via the Internet or via RF signals. The smart power meter1660may be operable to wirelessly transmit a digital message including the received demand response command to a demand response orchestrating device1662, which may be, for example, plugged into a standard electrical receptacle1649. In response to receiving a digital message from the smart power meter1660, the demand response orchestrating device1662is operable to subsequently transmit digital messages including, for example, the demand response preset, via the RF signals1606to the dimmer switch1610, the motorized roller shade1620, the temperature control device1630, the controllable electrical receptacle1640, and the plug-in load control device1642. Accordingly, as shown by the example data in Table 1, the dimmer switch1610reduces the present lighting intensity LPRESof the lighting load1612by 20% and the electronic drive units1626move the respective shade fabrics1622to the fully-closed position in response to receiving the demand response command. In response to receiving the utility-company command, the temperature control device1630also increases the setpoint temperature TSETby 2° F. when the HVAC system1632is presently in the cooling mode, and decreases the setpoint temperature TSETby 2° F. when the HVAC system1632is presently in the heating mode. In addition, the demand response orchestrating device1662may comprise one or more buttons1664for selecting the energy-savings presets. Alternatively, the smart power meter1660may be operable to wirelessly transmit digital message directly to the dimmer switch1610, the motorized roller shade1620, the temperature control device1630, the controllable electrical receptacle1640, and the plug-in load control device1642.

The load control system1600may further comprise a wireless occupancy sensor1668. The occupancy sensor1668is operable to wirelessly transmit digital messages to the dimmer switch1610, the motorized roller shade1620, the temperature control device1630, the controllable electrical receptacles1640, and the plug-in load control device1642in response to detecting an occupancy condition or a vacancy condition in the space in which the occupancy sensor in mounted. For example, the dimmer switch1610, the motorized roller shade1620, the temperature control device1630, the controllable electrical receptacles1640, and the plug-in load control device1642operate according to the away preset in response a vacancy condition, and according to the normal preset in response to an occupied condition.

The load control system1600may further comprise a wireless daylight sensor1669for measuring the ambient light intensity LAMBin the room in which the daylight sensor is mounted. The daylight sensor1669is operable to wirelessly transmit digital messages to the dimmer switch1610, the motorized roller shade1620, the temperature control device1630, the controllable electrical receptacles1640, and the plug-in load control device1642in response to the ambient light intensity LAMBin the space in which the daylight sensor in mounted. The motorized roller shade1620may be operable to control the position of the shade fabric1622in response to amount of daylight entering the building through the window as part of the eco-saver preset. In addition, the motorized roller shade1620could control the position of the shade fabric1622in response to the present time of the year and the present time of the day as part of the eco-saver preset.

According to another embodiment of the present invention, after receiving a demand response preset, the temperature control device1630is operable to transmit RF signals1606to the control devices of the load control system1600in response to the data representative of the energy usage information of the HVAC system1632stored in the memory1698. For example, the controller1690of the temperature control device1630may be operable to execute an HVAC monitoring procedure similar to the HVAC monitoring procedure1150shown inFIG. 15Bto control the motorized roller shade1620in dependence upon the data representative of the energy usage information of the HVAC system1632. The controller1690is operable to monitor the operation of the HVAC system1632for the predetermined time period (e.g., approximately one hour) after the motorized roller shade1620moves the shade fabric1622in a first direction from an initial position, and to determine if the HVAC system1632is consuming more energy than when the shade fabric was in the initial position (i.e., if the heating and cooling system is consuming more energy at the end of the predetermined time period than at the beginning of the predetermined time period). The controller1690is then operable to transmit a digital message to the motorized roller shade1620, such that the motorized roller shade moves the shade fabric1622in a second direction opposite the first direction if the HVAC system1632is consuming more energy than when the shade fabric was in the initial position.

Specifically, in response to receiving a demand response preset, the motorized roller shade1620is operable to open the shade fabric1622from the initial position to allow more sunlight to enter the room when the HVAC system1632is heating the building, to thus attempt to warm the room using daylight. If the controller1690of the temperature control device1630then determines that the HVAC system1632is not subsequently saving energy, the controller may transmit a digital message including a command to close the shade fabric1622(e.g., to the fully-closed position) directly to the motorized roller shade1620via the RF transceiver1695. Similarly, when the HVAC system1632is cooling the building, the motorized roller shade1620could close the shade fabric1622from the initial position to allow less sunlight to enter the room, and open the shade fabric (e.g., to the fully-open position) if the HVAC system is not subsequently saving energy. Alternatively, the controller1690of the temperature control device1630could simply transmit the data representative of the energy usage information of the HVAC system1632to the motorized roller shade1620, and the motorized roller shade could response appropriately to the data representative of the energy usage information of the HVAC system.