FR2765357A1 - AUTOMATIC CONTROL DEVICE FOR TWO ELECTRIC UNITS AND APPLICATION TO A DUAL POWER WATER HEATER - Google Patents

Abstract

This device makes it possible to use an electrical appliance while taking advantage of the privileged ranges of electricity consumption and using only a single power supply line. It comprises, on the one hand, a control logic circuit (13) placed on a single supply line (12P, 12N, 12T) and controlling a first contactor (19) according to the time slots. It also comprises a control terminal block (11) comprising two thermostats contactors (16, 17) each relating to a heating element (2, 3) of the hot water tank (1) and a second contactor (15). feeding the lower heating element (2). The latter is only used during periods of reduced tariff hours, the upper element (3) being used at the request of the user and inhibiting the lower heating element (2). Application to all electrical devices using two electrical consumption units and in particular to storage heating by double power water heaters.

Description

AUTOMATIC MANAGEMENT CONTROL DEVICE

TWO ELECTRICAL UNITS AND

  APPLICATION TO A DOUBLE POWER WATER HEATER

DESCRIPTION

  Field of the Invention The invention relates generally to devices using two electricity consumption units having different operating conditions as a function of external parameters. It relates in particular to dual power water heaters, that is to say using two heating elements in a hot water tank. This type of water heater is used in many industrial and domestic premises, such as private apartments. The particularity of operation of these water heaters is to use the time slots at a reduced rate of electricity consumption to heat all of the water in the tank, in order to reduce the cost of using the water heater in consumption of electricity. PRIOR ART AND PROBLEM POSED With reference to FIG. 1, the traditional double power water heater 1 uses two heating elements which are generally a lower electrical resistance 2 placed in the lower part of a hot water tank 8 and accompanied by a first thermostat 31, and an upper electrical resistance 3 placed in the upper part of this same hot water tank 8 and accompanied by a second thermostat 32. These electrical resistors 2 and 3 are supplied with electricity each by a line of supply respectively 5 and 6. Each line has a circuit breaker 10 placed in the subscriber's electrical panel. The tank 8 is completed by a water inlet pipe 6 opening into the lower part of the tank 8 and a hot water intake pipe 7

  opening into the upper part of this balloon 8.

  The lower resistor 2 is supplied during the hour range at a reduced rate of electrical consumption, that is to say during the night and therefore heats all of the water contained in the tank 8 during this period. However, during the range of hours with a high consumption tariff, namely the day, the mass of hot water initially contained in the tank 8 gradually cools as consumption takes place. The user can therefore feel the need to use the upper resistance 3 to heat the mass of water contained in the upper part of the tank 8, where the inlet of the hot water intake pipe 7 is located. case, it actuates a switch 9 to control the supply of the upper resistance 3. In addition, the consumption of water during the day can prove to be significant and the volume of the tank 8 will therefore be completed by the arrival of cold water, by means of the cold inlet pipe 6. As a result, the overall temperature of the mass of water contained in the tank 8 will probably no longer be sufficient to satisfy the user and the latter will therefore also feel the need to partially heat this mass using the upper resistance 3, by means of the switch 9 to heat the water in the

upper part of the balloon 8.

  A major drawback is that in this type of water heater and the installation attached to it, it is generally very difficult to install a

  second power line to supply the heater

  water. This therefore represents a handicap for the commercial development of this type of product. The object of the present invention is to remedy this

disadvantage.

  In addition, there is no communication or interaction between the two units which are independent of each other. This has the consequence that the two resistive heating elements can operate at the same time and thus cause a

  significant consumption of electricity.

  Summary of the invention For this purpose, the main object of the invention is therefore a device for automatically controlling and managing the power of an electrical appliance which uses two separate units for consuming electrical current from a source. power supply, the first being usable only in a determined time range. It includes: - control means for controlling the operation of the first or second consumption unit in the determined time range, and that of the second consumption unit outside this determined time range defined by a signal time range, as a function of usage demand signals established by measuring an electrical quantity identified and characteristic of the automatic operating needs of the two units and by usage need signal supplied for a contactor usable by a user as a function of these own needs, and - a single power supply line to supply the two units and being controlled

by the control means.

  In the main embodiment of the invention, the control means comprise: - a control circuit placed anywhere, connected to an electrical power source and receiving the first signal for measuring the electrical quantity by the line supply and the second signal by the need-to-use signal, and - control members placed on the one hand on the apparatus and receiving the supply line and on the other hand, on this same supply line. In the application of the device according to the invention to a water heater, the electrical quantity identified from the first signal being an electrical resistance, the control circuit comprises: - an intensity measurement circuit for measuring an intensity on the conductor phase of the power supply line;

  - a heater resistance measurement circuit

  water to measure the resistance of this heater

  water while operating; - a logic circuit for controlling the water heater receiving the measured values of the intensity and of the resistance and receiving a determined time range signal and the need for use signal given by the switch for measuring the resistance of the water heater and order the organs of

order based on measurements.

  In the context of the use of such a control circuit, the control members include: - a first contactor placed on the phase conductor of the supply line; and in a control unit placed on the water heater: - a first thermostat contactor for controlling the first unit which is a heating element; - a second thermostat contactor for controlling the second unit which is also a heating element; - a second contactor for supplying the first heating element; and - a relay supplied by the second second thermostat contactor to inhibit the first heating element when the second thermostat

is requesting.

  In a preferred embodiment of the control circuit, a third contactor is used placed at the input of the resistance measurement circuit to connect or not this latter to the power supply line and make the resistance measurement by injecting a current

  when the first contact is open.

  In this case, the control circuit is advantageously completed by a timing circuit to prevent the first contactor and the third contactor from being supplied simultaneously in transient mode. In order to detect possible failures of the water heater, the control circuit can be equipped with a fault detection circuit connected to the supply line to detect current flows to the first unit of the device and possibly

cut off the power to it.

  List of Figures The invention and its various technical characteristics will be better perceived on reading the

  following description of an embodiment,

  accompanied by figures representing respectively:

  - Figure 1, already described, a diagram of a heater

  water equipped with the device according to the prior art, - Figure 2, a diagram of a water heater equipped with the device according to the invention, - Figure 3, a diagram of the device according to the invention in its main embodiment, and Figure 4 , a diagram of the device according to

the invention in a variant.

  Detailed description of two embodiments of

  the invention With reference to FIG. 2, the control device according to the invention is always used to control a water heater 1. By comparing with FIG. 1, it is easy to see the difference between these two figures, it that is to say the presence of a single -7 supply line 12 for the water heater 1. In fact, the latter has the same hot water tank 8 as that shown in FIG. 1. Only the members have changed. There is a single supply line 12 of a control circuit 13, placed anywhere on the supply line 12 and a control box 11 placed near the water heater and receiving the line d 'power supply 12. This control unit 11 comprises a part of the control members of the water heater, the control circuit 13 comprising the other control members. In this FIG. 2, this control unit 11 has been placed in the lower part of the water heater 1, opposite the lower resistance 2. This is only an example of embodiment, the control unit 11 being able to be placed anywhere on the water heater 1. A secondary control line 14 supplies the upper resistance 3, the control unit directly supplying the

lower resistance 2.

  The control unit 11 is better detailed in FIG. 3. In fact, its main components and the main connections are shown. The secondary power supply 14 of FIG. 2 has disappeared so that the diagram of this control circuit 11 is represented in an enlarged manner, and not on the scale of the water heater.

1 and in particular of his balloon 8.

  The single supply line 12 in FIG. 2 is represented by these three conductors which are a phase conductor 12P, a neutral conductor 12N and

a 12T earth conductor.

  The organs which control the electrical supply of the two heating elements 2 and 3, by means of two terminal blocks, the upper one 30,

  the other lower 29, are as follows.

  A first contactor 19 is placed on the supply line, and in particular on the phase conductor 12P. It is shown here forming part of the control circuit 13 but could be placed elsewhere. The supply of the two heating elements 2 and 3 by this phase conductor 12P is done by two branches of the supply by the phase conductor 12P of the upper heating element 3 on which there are respectively two thermostat switches 16 and 17 On the bypass of the first thermostat switch 16 there is also a relay 18. The latter controls the opening and closing of a second switch 15 placed on a third tap connected to the lower heating element 2 via the terminal block 29. So when the

  first thermostat 31 requires heat,

  that is to say that if the contactor of the first thermostat 16 is closed in the diagram of FIG. 3, the relay 18 can be supplied, provided however that the second thermostat 32 is not a heat requester, that is to say that it does not short-circuit this relay 18 while it is closed. In other words, when the second thermostat contactor 17 relating to the upper heating element 3 is closed, that is to say that the upper heating element 3 operates, the relay 18 keeps the second contactor 15 placed open. on a bypass of the 12P phase conductor

  supplying the lower heating element 2.

  Thus, the operation of the upper heating element 3 has priority over the operation of the lower heating element 2, at the request of the second thermostat 32 relating to the upper heating element 3. If the first thermostat 31 is requesting and the second thermostat 32 is not, i.e. if the first thermostat switch 16 is closed and the second thermostat switch 17 is open, the relay 18 closes the second switch 15 supplying

  thus the lower heating element 2.

  The control circuit 13 comprises an electrical supply box 21 connected to the supply line, and more precisely to the phase 12P and neutral 12N conductors. It also includes a logic control circuit 22 receiving output signals, both from an intensity measurement circuit 23

  and a resistance measurement circuit 24 of the heater

  water. The intensity measurement circuit 23 is placed in shunt on a part of the phase conductor 12P to measure the intensity of the current sent and consumed by the water heater. The resistance measurement circuit 24

  therefore measures the operating resistance of the heater

  water across the 12P and neutral 12N conductors. Indeed, it must be taken into account that the first contactor 19 placed on the phase conductor 12P is systematically open for a determined period of time which corresponds to the hours at high tariff for electricity consumption. It is then impossible to know the possible operating resistance of the water heater without sending current to the terminals of the latter. This is the purpose of the resistance measurement circuit 24 which, via a third contactor 26, injects a current of low intensity into the water heater to measure its resistance. When the first contactor 19 is closed, that is to say during the hours at a reduced rate of electricity consumption, the intensity measurement circuit 23 does its job to measure the

resistance of the water heater.

  To allow control of this first contactor 19 as a function of the time slots, the control logic circuit 22 receives a signal H characteristic of these time slots. It also receives a signal U from a switch not shown and actuated by the user requesting or not an increase in the temperature of the water compared to the temperature usually obtained. This

signal a so-called comfort signal.

  A timing circuit 25 completes the logic control circuit 22 to prevent the first contactor 19 and the third contactor 26 from being supplied simultaneously in transient mode, which

  would fault the operation of the assembly.

  We now propose to explain the

operation of this device.

  The control unit 11 is therefore designed so that the first thermostat switch 16 can only supply the lower heating element 2 if the second thermostat switch 17 is open, that is to say not requesting. Heating the upper heating element 3 therefore has priority over heating the lower element 2. You can never have these two heating elements 2 and 3 in

running at the same time.

  il During the hours of consumption at high tariff, the input of the control logic circuit 22 receiving the signal H is activated. When the input receiving the signal U from the user is activated by a contact on the switch, the control logic circuit 22 must detect a request from the second thermostat 32 associated with the upper heating element 3 to authorize heating. If this second thermostat is in demand, the water heater is supplied, the first contactor 19 being closed. If this second thermostat 32 is not in demand, the water heater is not supplied because the logic control circuit 22 opens the first

contactor 19.

  During the consumption periods of hours at a reduced rate, the water heater is permanently supplied because the control logic circuit 22 keeps the first contactor 19 closed. In the event of simultaneous requests from the two thermostats 31 and 32, the upper heating element 3 is powered as a priority, as explained above. The lower heating element is only supplied when the upper heating element

is more.

  An example of resistance measurement of the water heater will be explained in the following lines. The resistance measurement takes place when the first contactor 19 is open and is carried out by injecting a low direct current, the second contactor 15 being closed. If the first thermostat 31 is the only requester, the logic control circuit measures a resistance for example greater than 4 kQ. If the two thermostats 31 and 32 are not requesting, the logic control circuit therefore measures an infinite resistance. If the second thermostat 32 is requesting, with or without the first thermostat 31 requesting, the control logic circuit 22 measures a resistance of the water heater of the order of Q, ie the resistance of the upper heating element 3 alone. The logic control circuit therefore then decides to switch to current measurement by closing the first contactor 19 and opening the second

contactor 15.

  The current injected into the water heater is therefore measured using the current measurement circuit 23

  connected to a portion of the 12P phase conductor.

  When the second thermostat 32 is requesting, the measured current is of the order of 16 A. If the measured current drops below 10 A, this means that only the first thermostat 31 is requesting and the logic control circuit 22 cut the power by opening the first contactor 19. It then closes the second contactor 15 to proceed

  to a possible future resistance measurement phase.

  The advantages of such an automatic power control and management device are: - the limitation of the power drawn from the electricity distribution network, - the use of a single supply line for the device, and

- optimization of the comfort provided.

  Regarding this last point, it is very interesting to use a circuit allowing

  detect a heater fault or malfunction

  water. Figure 4 shows the same device described in Figure 3 supplemented with a circuit of this type. Indeed, a fault detection circuit 27 is incorporated into the control circuit 13. More precisely, it receives the output of the intensity measurement circuit 23, and the signals H relating to the time ranges and U of the user's wishes . This circuit 27 is a

summing-type circuit.

  In fact, if only the lower heating element 2 no longer works or is broken down, and in the event of poor user drawing, the latter risks not

  quickly detect the heater malfunction

  water. This explains that, in this case, the hot water tank will be heated only at the request of the user using the heating element

higher 3.

  This fault detection circuit 27 therefore counts the passages in hours at a reduced rate. After a certain number N, for example 3 (which would correspond to 3 nights), in such a case,

  circuit 27 emits a signal to completely shut down the heater

  water to the control logic circuit 22. A reset of the control logic circuit is

  possible by general interruption of electrical energy.

  This allows heating to be resumed, in hours at a high rate or in hours at a reduced rate, by means of the upper heating element, while waiting for the entire water heater to be repaired. This fault detection circuit 27 also provides for systematically cutting off the operation of the lower heating element 2 when the upper heating element 3 no longer works. In this case, the hot water tank cools down and the user notices that it does not work after a few hours. A warning lamp can advantageously complete this circuit

failure detection 27.

  In the automatic power control and management device described, that is to say applied to a water heater, the electrical quantity identified and measured is the resistance of the water heater and its heating device, the heating elements being consumption units. One could very well imagine measuring impedances or capacities of other devices, for example motors, heat pumps, etc. This device can therefore have an application

important industrial.

  The preferred application of this device is

  of course the one with double power water heaters.

Claims (7)

  1. Device for automatically controlling and managing the power of an electrical appliance, which uses two separate units for consuming electrical current from a power source, the first consumer unit (2) being usable only in one determined time range defined by a time range signal (H), the device comprising: - control means for controlling the operation of the first (2) or second consumption unit (3) in the time range determined, and that of the second consumption unit (3) outside this determined time range defined by a time range signal (H), as a function of a request for use signal established by measuring an electrical quantity identified and characteristic of the automatic operating needs of the two consumption units (2 and 3) and of a usage need signal (U) coming from a contactor usable by a user in f anointing of these own needs, and - a single power supply line (12N, 12P, 12T) to supply the two units (2 and 3) and being controlled by the control means. 2. Device according to claim 1, characterized in that the control means comprise: - a control circuit (13) placed anywhere, connected to an electrical power source and receiving a first signal for measuring the quantity electric identified by the power supply line (12N, 12P), and the second signal which is the need for use signal (U), and - control elements (11, 19), some being placed on the device to control and receive the power line (12N, 12P, 12T) and others being placed on a conductor   phase (12P) of the power line.   3. Device according to one of claims 1 or   2, the controlled device being a water heater, the electrical quantity identified being an electrical resistance, characterized in that the control circuit (13) comprises: - an intensity measurement circuit (23) for measuring the intensity on the phase conductor (12P) of the supply line, - a resistance measurement circuit (24) for measuring the resistance of the water heater and placed on the supply line (12P, 12N), and - a control logic circuit (22) receiving the measured values from the intensity measurement (23) and resistance measurement (24) circuits, receiving the time range signal (H) and the need for use signal (U ) given by a switch for measuring the resistance of the water heater and controlling the control elements (19, 11) according to measurements. 4. Device according to claim 3, characterized in that the control members comprise: - a first contactor (19) placed on the phase conductor (12P) of the supply line, and in a control unit (11) placed on the water heater: - a first thermostat switch (16) relating to the first consumption unit (2) which is a lower heating element, - a second thermostat switch (17) relating to and controlling the second heating unit consumption (3) which is an upper heating element, - a second contactor (15) to supply the lower heating element (2), and - a relay (18) to inhibit the upper heating element (2) when the contactor second thermostat (17) is requesting.   5. Device according to any one of   claims 3 or 4, characterized in that the circuit   control (13) has a third contactor (26) placed at the input of the resistance measurement circuit (24) to connect or not this one to the supply line (12P, 12N) and make the resistance measurement of the water heater by injecting an electric current when the first contactor (19) is open. 6. Device according to claim 5, characterized in that the control circuits (13) have a timing circuit (25) to prevent the first contactor (19) and the third contactor (26) from being supplied simultaneously in transient mode . 7. Device according to claim 2, characterized in that the control circuit (13) has a fault detection circuit (27) connected to the resistance measurement circuit (23) for detecting   the current flows and cut off the total operation of the latter when one of the two units (2, 3) no longer works.