WO2009053695A1

WO2009053695A1 - A method of reducing power consumption and related apparatus

Info

Publication number: WO2009053695A1
Application number: PCT/GB2008/003587
Authority: WO
Inventors: Matthew James Smith; William Thomas Smith
Original assignee: One Switch Limited
Priority date: 2007-10-23
Filing date: 2008-10-23
Publication date: 2009-04-30

Abstract

A method of reducing the electrical power consumption of at least one electrical appliance within a building, comprising the steps of: connecting at least one receiver unit (130) to the at least one electrical appliance and to a power supply circuit (140), the receiver unit (130) arranged to receive a control signal; connecting a control unit (110) to the power supply circuit (140), the control unit (110) arranged to transmit the control signal; and providing at least one user operable switch (120) connected to the control unit(110); wherein actuation of the switch (120) is arranged to cause the control unit (110) to emit the control signal, wherein, upon receipt of the control signal, the receiver unit (130) is arranged to isolate or reconnect the at least one electrical appliance from or to, respectively, the power supply circuit (140).

Description

A METHOD OF REDUCING POWER CONSUMPTION AND RELATED

APPARATUS

Field of Invention

The invention relates to a method of reducing the power consumption, and in particular the electrical power consumption particularly, but not exclusively, in a building. The invention also provides related apparatus.

Background of Invention

The consumption of electrical power by appliances used in a building or vehicle, such as business premises or domestic dwellings (hereinafter building), car, coach, ship or the like, is ever more important to those parties that wish to reduce the running costs and life expectancy of these appliances, and who are increasing interested in reducing the carbon footprint of their building, whether for altruistic reasons or for the financial rewards that it gives them. As such, there is a drive to reduce the average power consumption of a building.

One problem that has been identified in reducing such power consumption is the power that is wastefully used when an appliance is switched to so-called stand-by mode. When in this mode appliances consume electricity which can be significant. Figures have been produced by the Energy Saving Trust which show that VCRs and DVD player alone produce, per annum, roughly 1 million tonnes of CO₂ between them whilst is stand-by mode. However, such stand-by modes have become convenient for the users of many buildings, and as such it can be undesirable for many such users to manually switch on and off these appliances within a building between the times that they are in use and not in use, such as after the close of an office or during the night in a domestic dwelling. One such system that has been devised to solve this problem is uses an RF signal, emitted from a remote control device, to communicate with an intermediary receiver positioned between an appliance and its power supply, wherein upon receipt of the RF signal the receiver is arranged isolate the appliance. Such systems are however limited in that the RF signals are unable to travel either through walls, or at great distances. In addition, the provision of a further remote control device within a building is undesirable. Such device can be expensive to replace once lost, and require a continued supply of battery power. User apathy towards either replacing the unit when lost, or the batteries once these have been consumed adds to the inconvenience of such a system. It will also be appreciated that use of batteries is in itself environmentally unfriendly.

Summary of the Invention

According to a first aspect of the invention there is provided a method of reducing the electrical power consumption of at least one electrical appliance within a building, comprising the steps of: connecting at least one receiver unit to the at least one electrical appliance and to a power supply circuit, the receiver unit arranged to receive a control signal; connecting a control unit to the power supply circuit, the control unit arranged to transmit the control signal; and providing at least one user operable switch connected to the control unit; wherein actuation of the switch is arranged to cause the control unit to emit the control signal, wherein upon receipt of the control signal by the receiver unit is arranged to isolate the at least one electrical appliance from the power supply circuit.

Such a method is advantageous as it provides a switch that can be used to isolate at least one, and generally a number, of electrical appliances from the power supply circuit to which they are connected. As such it can aid user of the system to reduce his/her power consumption within a building. It will be appreciated that the user operable switch is remote from the receiver unit. The connection between the control unit and the user operable switch implies a data connection which may or may not imply a physical connection.

In one embodiment, the control unit transmits the control signal over the power supply circuit.

Additionally, or alternatively, the control unit is arranged to transmit the control signal to the receiver unit using a wireless protocol, which may be, for example,

WIFI (IEEE 802. HX where X is any of the derivatives), Bluetooth™, WiMAX,

ZigBee, Wireless USB, etc. However, it is conceivable that other wireless technologies might be used. For example, media other than radio waves might be used such as for example, IrDA (Infrared Data Association). Such an arrangement is convenient in environments in which the power supply circuit comprises a three phase power supply circuit across which it can be problematic to use mains borne signalling techniques.

Conveniently, the receiver unit is connected between the at least one electrical appliance and the power supply circuit.

The method may allow a user to re-connect the at least one electrical appliance to the power supply circuit by further actuations of the switch.

The method may provide a plurality of user operable switches, actuation of any one of which causes the control unit to emit the control signal. Providing such a plurality of switches would enable the apparatus operated by the method to be activated from a plurality of locations within a building; i.e. generally each of the switches would generally be provided at a different physical location. Conveniently, there are a plurality of receiver units connected to the power supply circuit and as such a plurality of electrical appliances may be controlled by the method.

Generally, each receiver unit isolates or reconnects power from a power supply terminal, which would generally be an electrical socket. As such each receiver unit may be able to control a plurality of electrical appliances.

The control unit may draw its power from the power supply circuit. Such a method is convenient as it removes the need to separately power the control unit. Alternatively, or additionally, the or each receiver unit may be arranged to draw its power from the power supply circuit.

In some embodiments the user operable switch is powered by a power supply other than the power supply circuit. Such a method is convenient when the switch is being retro fitted to an existing power supply circuit. The method would allow the switch to be provided on a lighting circuit of a power supply circuit, which, as the skilled person will appreciate, does not have power within it when lights connected to that lighting circuit are turned off.

The user operable switch may be battery powered. Alternatively, or additionally, operation of the switch is arranged to generate power to generate a signal to cause the control unit to emit a signal.

The user operable switch may be wirelessly connected to the control unit which provides greater flexibility as to where the switch may be situated. The wireless connection may be provided by a radio wave which are advantageous as they do not require line of sight as would a light wave. Should the user operable switch be wirelessly connected to the control unit it is likely that it will be remote from the control unit. However, it is possible that the user operable switch, whether wirelessly or wired to the control unit, be remote from and/or provided on the control unit. The control unit is believed advantageous in embodiments that have a wireless connection between the user operable switch and the control unit since it may allow a short range wireless protocol to be used between these whilst still being able to communicate with receiver units over a longer distance.

The control signal is conveniently transmitted using a so-called mains borne signalling protocol, such as XlO. This is convenient as it provides a simple way to transmit signals to the electrical appliances that it is desired to isolate which does not require line of site and which is not blocked by walls, etc. as might radio waves, etc.

The method may use an identifier, which may be unique, in communications between the control unit and a receiver unit in order to specify which receiver unit should respond to the control signal. Such an identifier can help to prevent device being operated and/or isolated that it is not desired to operate and/or isolated. Generally each identifier is assigned to a specific receiver unit allowing that unit to be addressed. Thus, the method may provide a method of isolating user selectable receiver units. The user selectable receiver units may not be all of the receiver units that are in communication with the control unit.

The method may be used across a plurality of buildings which share the same power supply circuit. However, each user operable switch will generally be used to address a set of receiver units. Any identifier will generally be unique within the set of receiver units in order that a receiver unit can be addressed as desired.

The method may comprise pairing each receiver unit with a control unit. Such a method is convenient because it provides an easy way to add a receiver unit to the network of receiver units in communication with the control unit.

The power supply circuit may comprise any electrical supply wiring within a building or vehicle, whether intended to carry power to electrical appliances, lighting, etc. It will be appreciated that, in the United Kingdom at least, separate circuits are provided for lighting and power supply and the power supply circuit may comprise either of these.

The method may comprise building a receiver unit into one or more electrical appliances such that when the appliance is connected to the power supply circuit that appliance can be operated by the control signal generated by actuation of the manual switch. Such a method is advantageous as it allows an appliance to be directly connected to the power supply circuit without the need for a receiver unit being positioned between the two. It will be appreciated that a signal present on the power supply circuit is likely to pass into the appliance.

In some embodiments, the receiver unit comprises a discrete unit which is arranged to be plugged into an electrical outlet socket. Such an arrangement provides a flexible system which is easy for a user to install and may be installed with little modification to the building, etc. in which it is to be installed.

The user operable switch may be provided by a physical switch that a user can actuate (i.e. a manually operable switch), by pressing or the like. In other, alternative, or additional, embodiments, the user operable switch may be provided within an alarm system such that setting of the alarm causes the switch to be operated and the control signal sent. Using an alarm to send the control signal might prove advantageous as it would allow the at least one electrical appliance to be isolated from the supply when the alarm is set thereby increasing the safety of the building since the power will be isolated from the at least one appliance when the building is un-occupied (i.e. the alarm set).

The method may re-activate the at least one electrical appliance when the alarm is un-set. Typically, each of the user operable switches comprises a single switch, which may be of similar dimensions to a light switch. The provision of such a switch is advantageous as it makes controlling the at least one electrical apparatus much easier for the user; they have only to press one relatively large switch. In some embodiments, the single switch may be provided in a bank of switches such that only one of that bank provides the user operable switch.

The user operable switch may be mounted on a wall, or other similar building structure. Placing the switch on a vertical surface may be convenient as it may make if less likely for a pet, etc. to activate the switch.

Conveniently, the user operable switch may be fitted in an existing housing (such as a wall box) for a switch.

The user operable switch is conveniently a dedicated switch which can be used to remove and / or restore power to the at least one electrical appliance.

The user operable switch may conveniently be provided within a building utility switch. Such building utility switches include light switches, power outlets, etc. The user operable switch may be provided in addition to a building utility switch at the same location; ie the user operable switch and one or more building utility switches may be provided on the same faceplate.

According to a second aspect of the invention there is provided an electrical appliance isolation system, comprising: a control unit arranged to connect to a power supply circuit, and transmit at least one control signal; at least one receiver unit arranged to connect to an electrical appliance and a power supply circuit, and further arranged to isolate the electrical appliance from a power supply circuit on receipt of the control signal; wherein the control unit is connected to a user operable switch, the activation of which is arranged to cause the control unit to transmit the control signal.

The apparatus of this aspect of the invention may comprise any feature to implement the method of the first aspect of the invention.

In some embodiments of the invention the control unit is arranged to transmit the control signal over the power supply circuit.

Additionally, or alternatively, the control unit is arranged to transmit the control signal using a wireless communication methodology.

According to a third aspect of the invention there is provided a receiver unit arranged to be used in the method of the first aspect of the invention, the receiver unit being arranged to be connected to a power supply circuit and have an electrical appliance connected thereto such that power from the power supply circuit can be supplied to the electrical appliance, the receiver unit comprising a receiver circuit arranged to receive a control signal wherein upon receipt of a control signal the receiver unit is arranged to isolate the power supply circuit from an electrical appliance connected thereto.

According to a fourth aspect of the invention there is provided a kit of parts arranged to provide the method of the first aspect of the invention and comprising a control unit arranged to be connected to a power supply circuit; a receiver unit arranged to be connected to the same power supply circuit as the control unit; and a user operable switch arranged to be connected to the control unit.

According to a fifth aspect of the invention there is provided an electrical appliance incorporating a receiver unit which is arranged to be used in conjunction with the method of the first aspect of the invention. The electrical appliance may be any of the following: a washing machine; a tumble drier; a television set; a VCR (Video Cassette Recorder); a DVD player (whether recordable or not, whether high definition or not); a microwave oven; a games console (such as an XBOX ™, a PLAYSTATION™, etc.); a stereo system; a set top box; a computer, printers, photocopiers, fax. machines, lights, lamps or the like.

Brief Description of the Figures

There now follows by way of example only a detailed description of embodiments of the invention with reference to the accompanying drawings of which:

Figure 1 shows an exemplary schematic of an isolation system according to the present embodiment;

Figure 2 shows a further embodiment of an isolation system;

Figure 3 shows a flowchart outlining how the system of Figure 1 or 2 is used; and

Figure 4 shows a further embodiment.

Detailed Description of the Figures

Figure 1 shows an isolation system 100 according to an embodiment of the present embodiment. The isolation system 100 comprises a control unit 110 and four receiver units 130. It will readily be appreciated that the system may comprise any number of receiver units 130, such as 1, 2, 10, 50, 100, 1000 or any number therebetween. The control unit 110 comprises a switch receiver 111, a network input 114 and a signal emitter circuit 116. Additionally the control unit is arranged such that the signal emitter circuit 116 is able to draw electrical power from the network input 114. The network input 114 is connected to a power supply circuit 140 to which the receiver units 130 are also connected.

The system 100 further comprises a user operable switch 120, which itself comprises a switch generator 113 arranged to generate a signal upon activation of the switch 120. In the embodiment shown the link between the switch 120 and the control unit 110 is a radio link which provides a switch input 112 to the control unit. In the present embodiment the switch 120 is provided by a mechanical push switch. In addition the switch 120 is provided with a bias mechanism, such as a spring, arranged such that when the switch is not being activated (e.g. depressed) by a user, it remains in an open, unpushed position. In this position the switch input 112 remain electrically open.

In the embodiment being described, activation of the switch 120 generates sufficient power to cause the switch generator 113 to emit a radio signal which is received by the switch receiver 111. Such a device is provided by the EnOcean easyfit RCM 240 1- channel switching receiver.

Each receiver unit 130 comprises a network input 114, and further comprises a load input 132; i.e. a connection from a load to the receiver unit 130. Each receiver unit 130 is further provided with signal receiver circuit 134 and an isolating switch 136. In this embodiment the network input 114 is electrically connected to the load input via the isolating switch 136. The signal receiver circuit 134 is arranged to cause the isolating switch 136 to open and close when a control signal is detected at the network input 114. In a similar manner to above, each receiver unit is arranged such that the signal receiver circuit 134 can draw electrical power from the network input 114. Each of the signal emitter circuit 116 and the signal receiving circuit 134 comprise a processor together with associated memory, clock circuitry, etc. However, the signal emitter circuit 116 and/or the signal receiving circuit 134 may alternatively be provided my other electronic means such as programmable logic, discrete components, etc.

The system 100 is arranged to be connected to an existing power supply circuit 140, such as a building power supply circuit. The circuit 140 shown here comprises two power lines 145a, 145b. In the present embodiment one of these lines 145a is a so-called live line, while the other is a so-called neutral line 145b. Such a circuit 140 is indicative of many power supply networks, however it will readily be appreciated that the circuit 140 may comprise only one line 145a (for example in which the body of a vehicle or other metal work provides a neutral line), or that it may comprise more than two power lines 145a, 145b, for example by providing an additional 'earth' line, or potentially three phase wiring. A person skilled in the art will readily be aware of such arrangements.

In the embodiment being described, the existing power supply circuit 140 comprises four supply terminals 150, which are sockets, arranged to accept a standard electrical plug. In such an arrangement an electrical appliance provided with such an electrical plug may be connected to a supply terminal 150, and thus receive electrical power from the circuit 140 when the isolating switch 136 allows electricity to pass. The sockets 150 may or may not have external switches in order to control the supply of electricity from the socket 150. If such an external switch is provided then both of the isolating switch 136 and the external switch should be arranged to allow power to pass in order that an appliance can be supplied with electricity.

The isolating switch 136 is a double pole relay which is arranged to isolate both the live and the neutral connections to the power supply terminals 150 since this provides a greater degree of safety. However, in other embodiments, a single pole relay may be provided which would switch only one of the live 145a or neutral 145b lines. In other embodiments two single pole relays may be provided with one arranged to isolate the neutral line and the other arranged to isolate the live line.

In the present embodiment the network input 114 of the control unit 110 is connected between the live and the neutral lines 145a, 145b of the circuit 140. Such an arrangement allows the control unit 110 to draw electrical power from the circuit 140, which is used to power the signal emitter circuit 116.

Each network input 114 of each receiver unit is also connected between the live and the neutral lines 145a, 145b to the circuit 140. Again such an arrangement allows the receiver unit to draw electrical power from the circuit 140. Additionally, the load input 132 of each receiver unit 130 is connected to a supply terminal 150 of the circuit 140. In effect each receiver unit 130 acts as an intermediary between the supply terminal 150 and the circuit 140. The supply terminal 150 is therefore connected to the circuit 140, via the load input 132, the isolating switch 136 and the network input 112 of a receiver unit 130.

hi the present embodiment, a receiver unit 130 is connected to the supply terminal 150 of all those appliances whose average power consumption it is wished to reduce, such as printers, televisions, washing machines, DVD players, games consoles, etc. The receiver unit may be arranged to replace an existing socket 150 or may be arranged to be plugged into an existing socket. If arranged to be plugged into the socket it may be provided on a length of cable arranged to be plugged into the socket 150 or may be provided in a housing arranged to be received adjacent to the socket 150.

The switch 120 is arranged to be positioned in a user convenient position, such as in a bedroom of a residential dwelling, in proximity to stairs, or in the proximity of an exit of a building or at least in proximity to an exit of a floor of the building. The skilled person will appreciate that a flight of stairs provides an exit to a floor of a building. It will readily be appreciated that the control unit need not be provided at such a point, and may be displaced to an alternative location within the building. In the present embodiment, because the switch 120 wirelessly connects to the control unit 110 the switch need to be positioned within an existing switch of the power supply circuit.

As will be described in relation to Figure 3, when the user wishes to reduce the power consumption of designated appliances he or she activates the switch 120.

Upon such activation 300 (in this embodiment, this is closing of the switch), the switch input 112 is electrically shorted, the switch generator generates 113 which is received by the switch receiver 111 and the signal emitter circuit 116 emits a control signal 302 onto the circuit 140, via the network input 114. The control signal is then transmitted across the circuit 140, 304, using mains borne carrier wave technology and received at the network input 114 of each of the receiver units 130, 306. Upon receipt of the control signal, the signal receiver circuit 134 activates the isolating switch 136, 308, which isolates, 310 the load input 132 from the network input 112, and thus the supply terminal 150 from the circuit 140. This removes power from each electrical appliance connected to a supply terminal 150, which is connected to a receiver unit 130.

In a similar manner, when the user wishes to return power to electrical appliances connected to the supply terminals 150, he or she is able to activate again the switch 120, 300. Upon such activation, the switch input 112 is again electrically shorted and the signal emitter circuit 116 emits 302 a control signal onto the circuit 140, via the network input 114. The control signal is then communicated on the circuit 140, 304 and received at the network input 114 of each of the receiver units 130. Upon receipt 306 of the control signal, the signal receiver circuit 134 activates 308 the isolating switch 136, which connects 310 the load input 132 to the network input 112, and thus the supply terminal 150 to the circuit 140. This in effect re-establishes power to each electrical appliance connected to a supply terminal 150, which is connected to a receiver unit 130. Thus, operation of the switch 120 toggles appliances connected to the supply terminals between a connected and an isolated condition.

In this embodiment, the signal emitter circuit 116 associates an identifier with the control signal which is transmitted across the network. Each of the receiver units 130 is programmed with this identifier and as such responds to the control signal. Use of such an identifier helps to prevent the control signal interfering with receiver units 130 which it is not wished to control.

Figure 2 shows a further embodiment the present invention. Like parts with Figure 1 have been given the same reference numeral but starting with a 2 rather than the 1 used in Figure 1. This embodiment shows a system 200 in which the switch 220 is provided with a receiver selector 218. The switch 220 is connected by a wire (which provides a switch input 212) to the control unit 210. Such an arrangement might be suitable for incorporation into a switch which has both a live and a neutral cable connected thereto.

In addition, each receiver unit 230a-d is provided with a signal receiver circuit 234, which comprises a unique identifier, such as a Media Access Control (MAC) address, or the like. The receiver selector 218 is arranged to allow a user to select, from a plurality of receiver units 230, which units 230 the control signal should activate. The control unit 210 is arranged, upon activation of the switch 120, to emit a control signal on the circuit 140, which comprising information regarding the unique identifiers of those receiver units 230 which are to be activated by the control signal. A person skilled in the art will readily be able to implement such a system.

In this embodiment, the control unit 210 and each of the receiver units 230a to d are retro fitted to switches within an existing wiring circuit within a building. Such switches generally comprise a wall box on which a face plate is attached, with the face plate containing the switch. In this embodiment, the control unit 210 and the receiver units 230a to d is arranged to be positioned between the face plate and the wall box such that a home owner may maintain existing face plates when the system is retro fit.

Embodiments of the invention may also be arranged such that the control unit is additionally provided with a variable delay timer 370. In such embodiments the variable delay timer is used to provide a delay between the time when the switch is activated, and when the control signal is emitted which may be useful in allowing devices to remain on for a period of time; i.e. it allows an electrical appliance to be disconnected from the power supply circuit after a delay. In this embodiment, a variable resistor is provided on the receiver unit 130 such that a user can adjust the resistor in order to set the time delay. In other embodiments, the variable input may be provided by means other than a variable resistor.

In Figure 2 the receiver unit 230b is provided with a power sensor 280. The power sensor 280 is connected to the network input 214 and is arranged to observe the current flowing through this network input. In the present embodiment this is provided by a current transformer together with associated control circuitry which interfaces with the signal receiver circuit 234. The signal receiver circuit 234 is arranged to activate the isolating switch 236 only when there is provided from the power sensor an indication that the power being drawn by the supply terminal is less than a predetermined threshold.

In this arrangement, when the receiving unit 230 receives a control signal indicating that the unit should be switched off, this will only occur when appliance to which that unit is connected is in stand-by mode as indicated by the current being drawn by the appliance. Some embodiments may provide the switch 220 with an additional input which isolates appliances regardless of the current that they are drawing. In an alternative embodiment, the signal receiver circuit may be arranged such that when an appliance is receiving power, it stores the request of the control signal to activate the isolating switch, and continually monitors the power sensor 280 to evaluate when the power drops below a certain threshold. At that time the signal receiving circuit is arranged to activate the isolating switch. Such an arrangement may allow appliances, such as washing machines, dish washers or the like, to be electrically disconnected from the network once the appliances program has finished. In a further embodiment the signal receiving circuit is arranged to activate the isolating switch only after the power consumption has reduced below a predetermined threshold for a predetermine time, such as five minutes. Such an arrangement might be convenient for appliances such as washing machines which are likely to have periods of reduced power consumption as its cycle of operation progresses.

While in the above embodiment, the control unit and each receiver unit is powered from the network, via the network input 114,214, in alternative embodiments, each unit may be power by a battery or the like. The battery may be rechargeable, which may be charged from the network.

The switch 120 may also emit a signal using an acoustic or electromagnetic wave, such as a radio wave which communicates with the control unit 110, as does the EnOcean switch which communicates using a radio wave. Such communication is often referred to as wireless communication. Such a switch provides greater freedom as to the location of the switch 120.

The skilled person will appreciate that switches operating lighting circuits of a power supply circuit do not generally have a neutral wire running to them and as such the wiring to an existing light switch could not provide a network input 114, 214 since no neutral line 145b is present. Thus, it is problematic to retro fit a switch 120 to a lighting circuit. Use of the a switch that communicates wirelessly with the control unit 110 allows the switch 120 to be retrofitted into a lighting circuit switch, or indeed, would allow the switch to be provided remote from any existing power supply circuits.

In embodiments, in which the system is being installed in a new building switches of a lighting circuit of the power supply circuit may be provided in which both a live 145a, 245a and a neutral 145a, 145b and such an arrangement would allow the control unit 120 to be fitted within a switch and to be powered from the power supply circuit.

In some embodiments, the user operable switch may additionally, or alternatively, be provided within an alarm circuit such that when the alarm is set or un-set a control signal is sent to respectively isolate or un-isolate the at least one electrical appliance.

Figure 4 shows a further embodiment the present invention. Like parts with Figure 1 have been given the same reference numeral but starting with a 4 rather than the 1 used in Figure 1.

In this embodiment, each of the receiver units 430 comprises an aerial 438, which may be provided internally or externally of the unit 430, but in the embodiment shown are external thereto. The aerial 438 connects to the signal receiver circuit 434.

Likewise, the control unit 410 also comprises and aerial 442 which is again shown as being external of the control unit 410. However, in other embodiments, the aerial 442 may be provided internally. The aerial 442 is connected to the signal emitter circuit 116. This embodiments operates in a similar manner to those embodiments described previously except that the control signal is not sent via the power supply circuit 440a, 440b. Indeed, it will be seen that there is no connection between the control unit 410 and the power supply circuit 440a, 440b and as such the control unit 410 is supplied with power from a local power source 444, such as a battery or the like.

Thus, when a user presses the user operable switch 420 a switch input 412 is generated and received by the switch receiver 411. Although shown in a wireless manner this could also be by the wired connection as described in relation to Figure 2.

The signal receiver 411 causes the signal emitter circuit 416 to send a signal to the aerial 442 which is transmitted and subsequently received by the aerials 438 of the receiver circuits. The signal received at the aerials 438 is fed to the signal receiver circuit 434 which controls the isolating switch 436 to close or open as described hereinbefore.

The skilled person will appreciate that features described in relation to one embodiment are not necessarily limited to that embodiment and could be moved mutatis mutandis to be used in other embodiments.

Claims

1. A method of reducing the electrical power consumption of at least one electrical appliance within a building, comprising the steps of: connecting at least one receiver unit to the at least one electrical appliance and to a power supply circuit, the receiver unit arranged to receive a control signal; connecting a control unit to the power supply circuit, the control unit arranged to transmit the control signal; and providing at least one user operable switch connected to the control unit; wherein actuation of the switch is arranged to cause the control unit to emit the control signal, wherein, upon receipt of the control signal, the receiver unit is arranged to isolate or reconnect the at least one electrical appliance from or to, respectively, the power supply circuit.

2. A method according to claim 1 which provides the user operable switch within a building utility switch.

3. A method according to claim 1 or 2 in which the user operable switch is provided in proximity to an exit of the building, or at least in proximity to an exit of a floor of a building.

4. A method according to any preceding claim in which the control unit transmits the control signal using a wireless medium to the receiver unit.

5. A method according to any preceding claim in which the user operable switch is wirelessly connected to the control unit.

6. A method according to claim 5 in which the wireless connection is a radio frequency connection.

7. A method according to any preceding claim which powers the user operable switch by a power supply other than the power supply circuit.

8. A method according to claim 7 which powers the user operable switch with a battery

9. A method according to claim 7 in which operation of the switch is arranged to generate power to generate a signal to cause the control unit to emit a signal.

10. A method according to any preceding claim in which the control signal is transmitted using a mains borne signalling protocol across the power supply circuit.

11. A method according to any preceding claim in which an identifier is used in communications between the control unit and a receiver unit to specify which receiver unit should respond to the control signal.

12. A method according to any preceding claim in which the control unit draws its power from the power supply circuit.

13. A method according to any preceding claim in which the or each receiver unit draws its power from the power supply circuit.

14. A method according to any preceding claim in which there are a plurality of receiver units connected to the power supply circuit.

15. A method according to any preceding claim in which there is a plurality of electrical appliances controlled by the method and the control signal causes each of the apparatus to be isolated from or connected to the power supply circuit.

16. A method according to claim 15 which arranges for at least one of the electrical appliances to be disconnected from the power supply circuit after a delay.

17. An electrical appliance isolation system, comprising: a control unit arranged to connect to a power supply circuit, and transmit at least one control signal; at least one receiver unit arranged to connect to an electrical appliance and a power supply connected to the power supply circuit to which the control unit is attached, and further arranged to isolate the electrical appliance from that power supply circuit on receipt of the control signal received from the power supply circuit; wherein the control unit is connected to at least one user operable switch, the activation of which is arranged to cause the control unit to transmit the control signal.

18. An electrical isolation system according to claim 17 comprising a user operable switch which is wirelessly connected to the control unit.

19. An electrical isolation system according to claim 17 or 18 in which the user operable switch is powered by a power supply other than a power supply circuit to which the control unit is arranged to be connected.

20. An electrical isolation system according to claim 19 in which the user operable switch is arranged to generate power as it is operated.

21. A kit of parts, arranged to provide the method of any of claims 1 to 16 including: 1. a control unit arranged to be connected to apower supply circuit;

2. a receiver unit arranged to be connected to the same power supply circuit as the control unit; and

3. at least one, user operable, switch arranged to be connected to the control unit.

22. A receiver unit arranged to be used in the method of any of claims 1 to 16, the receiver unit being arranged to be connected to a power supply circuit and have an electrical appliance connected thereto such that power from the power supply circuit can be supplied to the electrical appliance, the receiver unit comprising a receiver circuit arranged to receive a control signal wherein upon receipt of a control signal the receiver unit is arranged to isolate the power supply circuit from an electrical appliance connected thereto.

23. An electrical appliance incorporating a receiver unit which is arranged to be used in conjunction with the method of any of claims 1 to 16.

24. A method of reducing the electrical power consumption of at least one electrical appliance within a building, comprising the steps of: connecting at least one receiver unit to the at least one electrical appliance and to a power supply circuit, the receiver unit arranged to receive a control signal transmitted along the power supply circuit; connecting a control unit to the power supply circuit, the control unit arranged to transmit the control signal across the power supply circuit; and providing at least one user operable switch at a user convenient position with the building such that it is wirelessly connected to the control unit; wherein actuation of the switch is arranged to cause the control unit to emit the control signal across the power supply circuit, wherein, upon receipt of the control signal, the receiver unit is arranged to isolate or reconnect the at least one electrical appliance from or to, respectively, the power supply circuit.

25. A method according to claim 24 in which the user operable switch is powered by a power source other than the power supply circuit.

26. A method according to any of claims 1 to 16 or 24 or 25 in which the user operable switch is provided on a wall of the building, generally in the vicinity of an exit to the building or at least to a floor of the building.