ENERGY CONTROL SYSTEM

Abstract: An energy control system for the control of energy consumption within an area including detection means for detecting the presence of a person within the area and control means responsive to the output of the detection means to control the energy consumption within the area. The system can also be used as a burglar alarm by turning lighting on if an intruder enters the defined area.

Description: ENERGY CONTROL SYSTEM The present invention relates to energy control systems and more particularly to the control of the use of energy consuming apparatus within a defined area or areas. At present in known systems for use in energy con¬ trol of heating and light apparatus within a defined area a number of different devices are used. To conserve en¬ ergy in heating a room in a building thermostats are used either on individual radiators or a conveniently situated room thermostat may be used. Additionally the heating system is normally on a timer to conserve heat for ex¬ ample at night and over weekends. For lighting control a timing circuit is often used particularly for communal areas such as stairs wherein operation of the timing cir- cuit switches on the light for a few minutes to allow the normal passage through the area. The above known systems suffer from a number of dis¬ advantages. Firstly in respect of the heating of a building the timer is normally set to cover all hours that the building would be occupied. Thus in respect of commercial premises this would cover the period from eight in the morning to eight at night allowing for over¬ time working and for cleaning. Also unless a complex seven day timer is installed the heating will be on all day Saturday and Sunday. Similarly for lighting purposes in large office or school premises the lights tend to be turned on when darkness falls and left on until the night watchman or caretaker turns them off or turned on the morning and left on all day even when not required. it is an object of the present invention to provide an energy control system which reduces energy consumption by automatically controlling the lighting and/or the- heating or the like in a building or part of a building to minimise the energy used whilst ensuring good environ- mental working conditions for employees. The consumption of power by heating and/or lighting or the like will hereinafter for brevity be referred to generally as en¬ ergy consumption. According to the present invention there is provided an energy control system for the control of energy con¬ sumption within an area including detection means for detecting the presence of a person within the area and control means responsive to the output of the detection means to control the energy consumption within the area. Preferably the detection means includes an infrared or microwave sensor or a sensor with combined infrared and microwave detection sensitivity. In a preferred embodiment the control means also includes means for detecting ambient light conditions for switching on lights when a predetermined inadequate low level of lighting is present and for switching off lights when a predetermined adequate higher level of lighting is present. Also preferably the control means includes a temper¬ ature detector which is operative with the control means to switch on the heating in an area only when the temper¬ ature falls below a specified first level and providing that the presence of a person is detected and to switch off the heating when the infrared or microwave sensor does not sense any person in the controlled area. The control means preferably includes a second temp¬ erature detector to maintain the temperature in the con¬ trolled area at a second low level to prevent freezing within the controlled area. Since the lights are, in a preferred embodiment, turned on by the intrusion or presence of a person within a defined area this may be linked to a burglar alarm system and will turn on the lights enabling the intruder to be easily seen. The mere action of switching on the lights may act as a suitable deterrent and an audible or remote alarm may also be given. Embodiments of the present invention will now be described, by way of example with reference to the accom- panying drawings in which:- Figure 1 shows a room equipped with an energy con¬ trol system according to the present invention; Figure 2 shows in block diagrammatic form the cir¬ cuitry of the control box of the energy control system of Figure 1 in greater detail; and Figure 3 shows the circuitry of Figure 2 in greater detail. With reference now to Figure 1, a room or area 10 is depicted by two walls 12, 14 and a floor 16 and ceiling 18. The area is lit by ceiling light fittings 20, 22 preferably of the fluorescent type controlled by a switch 24. The area is heated by, for example, warm air central heating through vents 26 controlled by one or more shut off grills 28. Water filled radiators and valves may be substituted for the warm air heating in known manner. The area 10 may be a workshop, office or hallway and at a suitable vantage point a detector 30 is mounted such that it can detect the presence of a person within the area 10. The detector may be of the microwave type or of the infrared type or may be a combined microwave and in¬ frared detector. The detector will continuously detect the presence and movement of any person within the area 10 as shown by dotted lines 32, 34. An ambient light sensor 36 is situated at a location within area 10 that is chosen such that the ambient light level at this location is representative of the ambient light within the area 10. Thus the sensor 36 should not be situated too close to a window, nor in an obscure corner since both locations would be non representative of the light conditions in the area generally. A room thermostat 40 is mounted on a convenient wall 12 and is used in known manner to monitor the temperature within the room 10. Preferably the thermostat 40 includes a low level second temperature (e.g. 40 F) which is maintained even when the area is not inhabited. The outputs of ambient light sensor 36 are connected to a control box 50 which produces outputs to control switch 24 and grill 28 as explained hereinafter. The thermostat 40 is only enabled when the detector senses the presence of a person in the area. The control box 50 includes circuitry shown in greater detail in Figure 2. Provided the room or area 10 is inhabited then, as ambient light diminishes lighting will be automatically switched on by operation of relay switch 24. This could occur for example during heavy rain or a thunderstorm. Following this event as ambient light increases the lights would be switched off. If the room or area 10 is not inhabited then the lights will not be operated. When the room or area 10 is vacated then if the lights are on they will be switched off after a defined delay period (say ten minutes). The control unit is continuously monitoring such that if an intruder enters the area 10 the lights would immediately be switched on and thus deter entry into this area. If an area contains many obstructions such as a warehouse then an acoustic detector may be used. The acoustic detector can be selectively filtered to ignore any continuous noises e.g. machinery such as air con¬ ditioning fans. Under normal circumstances a timer within the con¬ trol box, which produces the time delay for switching off the lights, is continually reset by detected noise, heat or movement of an inhabitant of the area such that the lights will remain on continuously. The advantages of such a system are that the timers are totally variable thus allowing switch off after very short or long periods of time to suit individual require- ments. If an acoustic infrared or microwave sensor is used then the sensitivity can be preset according to the type of location of the establishment containing area 10. Thus any inherent noise levels or heat sources can be compensated for. A reduction in energy consumption can be achieved even for very short periods for example break periods, lunch periods and intervals between classes in a school. Also between the end of day time classes and the σomm- encement of evening classes. The system when installed in shops and ' warehouses acts as an anti-vandal and/or anti-theft device. In the system of Figure 1 the heating can be con¬ trolled at the same time as the lighting. Thus an output on line 52 to shut off grill 28 can eliminate area 10 from the main heating changing thermostat 40 over to the low temperature standby mode. Alternately if the build¬ ing comprises only area 10 then an output may be sent on line 54 to shut down the heating boiler 56. Thus in a complete system both heating and lighting energy consumption is reduced even during short periods. A more detailed circuit diagram of the control box 50 is shown in Figure 2. The power for the circuitry is obtained from a mains supply (normally 240 volts) 100 which is transformed and rectified in known manner in circuit 102 to give a 12 volt output 104. This 12 volts output is used to power four integrated circuits 106, 108, 110, 112 as shown and the other circuitry comprising first and second relays 114, 116. The first relay 114 is an input sensing relay which is operated by the sensor to give an output when the sen¬ sor senses the presence of a person within the room and this relay provides when actuated an input to first logic circuit 106. The output of logic circuit 106 is fed to the second relay 116 and also to a second logic circuit 108. The output of second logic circuit 108 is fed to a timing circuit 110 the output of which is fed also to relay 116. The integrated circuit 112 is a comparator and the circuit compares the set light level with the present or ambient level sensed by sensor 36. If the ambient light level is too low a signal is sent to logic circuit 106 to attempt to turn the lights and/or heating on by operation of relay 116. This will only occur however if the sensor indicates the presence of a person in the defined area. The second logic integrated circuit 108 is used to instruct the timing circuit 110. If for example the last person leaves the defined area then sensors 30 will att¬ empt via logic circuit 30 to put out the lights and/or turn off the heating. The timer 110 will prevent this for a predetermined time set by the user according to the desired use in order for example for the person to be able to step into an adjoining store room and then move back in to the area within say five minutes. Similarly if the light sensor detects low ambient light and the sensor 30 does not detect any presence within the defined area then the logic circuit 106 will prevent actuation of relay 116 because there will be no requirement for any lighting or heating. The heating may be controlled either directly by relay 116 or by a similar separate relay (not shown) to turn on the heating boiler or a separate set of make con¬ tacts of relay 116 may be used in series with a room thermistor 40. In the latter case if thermistor 40 senses too low a temperature it will attempt to turn on the boiler. If relay 116 is not operated however there will be no continuous connection and the boiler will not operate. If relay 116 is then operated on sensing the entrance of a person the circuit will be completed and the boiler or shut off grills 28 will be activated to provide heat within the area. If a microwave detector is used then this will de¬ tect movement within the defined area. Thus is a person bends down behind an obstacle such as a cabinet for a short period the sensor will be de-activated. However timer circuit 110 will keep the lights on for the pre-set time and therefore there will for most normal circum¬ stances be no premature switching off of the lights. A more detailed circuit diagram of the block diagram of Figure 2 is shown in Figure 3 the significant circuits being identified by the same reference numerals. The circuit values and types for the circuit are as follows:- IC1 (106) CMOS4081 AND GATE LOGIC IC2 (108) COS4803 OR GATE LOGIC IC3 (110) 555 TIMING CIRCUIT IC5 (112) 311 COMPARATOR Rl 4.7 K ohms TIMER VARIATION POTENTIOMETER R2,R3,R5,R6 1 K ohms R4 1 M ohms R7 22 K ohms Dl -D7 IN4148 CO 47 μ F Cl 0.01 μ F C2 220 μ F C3,C4 0.1 jl F RL1,RL2 Radiospares 347-832 (8410) 12 volt DC 205 ohms By controlling the lighting relay 116 can, following actuation of a time switch in a known burglar alarm syst¬ em, be used not only to switch on the lights by also to actuate a burglar alarm. This can be either a local bell or a silent or remote alarm. The burglar can therefore be identified by virtue of the light being turned on and the area within which the burglar is present can be read¬ ily seen. In the case of a shop the shop can be easily identified by the switching on of the shop sign as well as the interior lights.

Claims: CLAIMS 1. An energy control system for the control of energy consumption within an area including detection means for detecting the presence of a person within the area and control means responsive to the output of the detection means to control the energy consumption within the area. 2. An energy control system as claimed in Claim 1 in which the detection means includes an infrared, a micro¬ wave or combined infrared and microwave detector. 3. An energy control system as claimed in Claim 1 or Claim 2 in which the control means includes means for detecting ambient light conditions to switch on lights within the area when a predetermined inadequately low level of lighting is detected and means for switching off the lights in the area when a predetermined adequate higher level of lighting is present. 4. An energy control system as claimed in any preceding claim in which the control means includes a temperature detector which is operative to switch on the heating in the area when the temperature falls below a specific first level providing that the presence of a person is detected and to switch off the heating when the detection means does not sense any person in the controlled area. 5. A burglar alarm system for the detection of intrud¬ ers within an area including detection means for detect- ing the presence of a person within the area and control means responsive to the output of the detection means to turn on the lighting within the area. 6. A burglar alarm system as claimed in Claim 5 in which the control means also actuates an alarm. 7. An energy control system constructed substantially as herein described with reference to the accompanying drawings. 8. A burglar alarm system substantially as described with reference to the accompanying drawings.

Inventors: BIRD WILLIAM DEREK, BIRD, WILLIAM, DEREK
Applicants: ROBOTRONICS LIMITED
Application year: 1985
Main classification: H05B37
IPC codes: G05D23, G08B13, H05B37