FR2954476A1 - METHOD AND SYSTEM FOR CONTROLLING A REVERSIBLE HEAT PUMP WITH THERMOELECTRIC MODULES - Google Patents

Abstract

The invention relates to the control of a reversible thermoelectric heat pump which comprises thermoelectric units (41, 42, 43, 44) with a plurality of thermoelectric modules (3) for transferring heat between two circuits of the pump. In particular, it is provided: - to provide a plurality of output connections (S1, S2, S3, S4) of the power supply (10) of the thermoelectric units; - program at least one temperature setpoint; - delivering, by temperature sensors (31), signals representative of characteristic temperatures of the two circuits; adjusting the voltage delivered at each of the output connections, by controlling said power supply, a switching device being configured according to the temperature setpoint and said signals, the configuration of the switching device being selected from a plurality of configurations with up to two levels of supply voltage of the modules (3).

Description

The present invention relates to heating or air-conditioning installations, and relates to a control system of a reversible heat pump of the thermoelectric type, that is to say, a system for controlling a reversible heat pump with thermoelectric modules. ie with thermoelectric modules also called Pelletier effect cells (CEP). The CEP each typically have two faces, one of which is of a first type called "cold" and the other of a second type called "hot", a heat transfer can be exerted from one side to the other depending on the direction of an electric current injected into the cell. It is understood that an inversion of the heat exchange allows a reversible operation of the heat pump, for example to cool a living room in summer by evacuating outward heat. More particularly, the invention relates to a control system of a reversible thermoelectric heat pump having two heat exchange circuits using a heat transfer fluid and a plurality of thermoelectric heat transfer units each comprising a determined number of thermoelectric modules adapted to transfer heat between the two circuits, the control system comprising: a power supply unit for connection to a power source and having a plurality of output connections for delivering a voltage of supply to each of the thermoelectric units; a set of temperature sensors adapted to deliver in particular signals representative of characteristic temperatures of the two heat exchange circuits; and a control device connected to an input device of a set temperature for controlling the power supply of the plurality of thermoelectric units according to said temperature set point and the signals delivered by said set of temperature sensors.

WO 2006/070096, of the same applicant, describes a power supply mode of the CEP, using a rectified AC low voltage rather than a DC voltage. CEPs are electrically connected in series and must be activated with voltages whose value is set to obtain an operating point of the heat pump. The voltage is thus set for a thermoelectric unit, so that an operational performance coefficient (COP) greater than 1 can be obtained. This choice is predetermined according to the expected operating conditions. It is understood that the temperature difference between the cold face and the hot face of the CEP depends on the chosen voltage. However, there is no device of this type currently commercially available. The current applications of thermoelectric modules mainly concern the production of refrigeration for electronic devices or travel refrigerators, that is to say applications where the heat exchange power is much lower than that required for a domestic heating system. typically provides a heat input power of a few kilowatts to 25 kW. Another limiting factor is the real coefficient of performance (COP) which degrades substantially when the operating conditions change and in particular the temperatures of the respective fluids flowing in the two circuits. Also, it is not envisaged this day to reach a COP higher than 4, contrary to the last traditional heat pumps which meet a great commercial success. As a reminder, these traditional heat pumps use a closed circuit in which a refrigerant such as a hydrofluorocarbon undergoes a compression / expansion cycle between a condenser and an evaporator. The object of the present invention is to propose a reversible thermoelectric heat pump control system which allows a better use of the thermoelectric modules. For this purpose, the subject of the present invention is a control system of the aforementioned type, characterized in that the power supply unit comprises a plurality of devices for adjusting the voltage delivered by each of the output connections, said devices an adjusting device comprising switches, at least a portion of the adjusting devices being adapted to deliver a plurality of predetermined voltage levels according to the state of the switches of said adjuster, and in that the controller is connected to the switches and adapted for controlling different switch configurations of the switches to selectively supply at least a portion of the plurality of thermoelectric units, and secondly, selecting the predetermined voltage level supplying the powered thermoelectric units. 35 Thus, it is allowed to adjust the power consumption according to

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representative parameters of heat transfer requirements. The control device advantageously makes it possible to configure the switches of a switching device to increase or lower, or even cut, the power supply of some thermoelectric units that consume the most electricity when the heating or cooling requirements are low. Selecting and adjusting the voltage of the activated thermoelectric units makes it possible to operate their thermoelectric modules (PEC) as close as possible to the ideal operating bridge and thus to increase the overall COP of the heat pump. In case of higher heat transfer requirements, an appropriate control can then be issued by the control device immediately to satisfy the demand: it can be to supply all the thermoelectric units to a maximum power level. and / or supply one or more thermoelectric units of greater power. The system can be particularly simple and responsive through the use of the switching device.

According to one feature, the control device comprises an electronic control unit which comprises: a parameterization module for setting a defined number of predetermined operating points of the heat pump, each operating point corresponding, on the one hand, to a number of thermoelectric modules supplied, and secondly, to a predetermined supply voltage for each of the thermoelectric units supplied; and an algorithm adapted to perform a correlation, as a function of said temperature setpoint and the signals delivered by said set of temperature sensors, between heat transfer requirements and a single operating point, so as to select the operating point which maximizes the coefficient of performance of the heat pump. Thus, servocontrol can be achieved simply and economically, the control device for regulating the ambient temperature of one or more premises by minimizing the number of CEP and / or the supply voltage of these CEP. According to a specific feature, the control device a conversion table for associating with a first of the voltage adjusting devices and a second of the voltage adjusting devices, a determined number of configuration commands that differ between they by at least one, and preferably two, of the following selected parameters: the state, representative of a selection of all or part of a thermoelectric unit, of first switches which are arranged between the electric power source and said first and second voltage control devices; and the state, representative of a selection of a voltage level, of second switches arranged at the first and second voltage control devices. Thus, it is permissible to define in a simple way (via switch positions) a range of operating points to optimize the COP.

According to one feature, the electric power source provides an AC power supply and the adjustment devices comprise: at least one converter with two outputs defined by four terminals, adapted to deliver two predetermined levels of voltage, each much lower than the voltage level of the source electric current; and switches arranged at the output of the converter for providing a predetermined output voltage level resulting from a combination of said two predetermined levels outputted from the converter. By combining voltage levels, it is of course understood that it is one of the following combinations, known either: superposition of voltage levels or selection of only one of the voltage levels. A switch may also be provided upstream of the converter to completely cut the power supply. According to one feature, the adjustment devices comprise a full-wave rectifier bridge and an output defined by two rectifier bridge junctions, at least one of the switches being configurable according to two positions, one of which makes it possible to deliver a first voltage with four terminals. at the output of the converter connected to two junctions of the rectifier bridge, and the other makes it possible to deliver a second voltage higher than the first voltage with only two of the four terminals at the output of the converter connected to two junctions of the rectifier bridge. Thus, it avoids using a continuous power source, which is expensive and bulky, and it can be obtained a rectified alternating low-voltage power supply. In various embodiments of the control system according to the invention, one or more of the following arrangements may also be used: the power supply unit comprises first output connections to power defined in an adjustable manner according to the configuration of the switching device, as well as second output connections with predefined power regardless of the configuration of the switches; the controller includes a conversion table for using either one or more of the first output connections or one or more of the second output connections. It is understood that each of the above provisions contributes to refine the adjustment of the operating point, without complicating the heat transfer part of the thermoelectric heat pump and minimizing the power consumed. The service life of the thermoelectric units and the associated supply units can be further increased by such selective operation as required. According to another particularity, the second output connections are each associated with an inverter device of the direction of the current that can be actuated by the control device. The reversible nature of the power supplied to one or more thermoelectric units, in a simple way, to switch from heating mode to cooling mode. At least for one of these thermoelectric reversal feed units, greater heating power can be provided. The control mode may, as needed, be simplified for one of the cooling or heating modes, for example by providing in the cooling mode to control only the thermoelectric units which are connected to the second output connections. Another object of the present invention is to propose a reversible thermoelectric heat pump whose electrical consumption is better adapted to the real needs in heat transfer. For this purpose, it is proposed a reversible thermoelectric heat pump, comprising two heat exchange circuits using a coolant and a plurality of thermoelectric heat transfer units each comprising a predetermined number of thermoelectric modules adapted to transfer the heat transfer medium. heat between the two circuits, characterized in that it comprises the control system according to the invention. Such a heat pump can be in the form of a device connecting to the urban electrical network and can be directly installed in a building by connecting to an existing central heating system or new forming the first circuit, such as a floor heating system, and a heat exchange system with the external environment forming the second circuit. The exchange system with the outside can be inter alia network type or tank buried in the ground, or exchange system with air or a body of water. According to one feature, a first one of the thermoelectric units comprises two series of thermoelectric modules, each of the two series being powered independently of one another by one of the first output connections of the power supply unit. Thus, a finer control of the power can be obtained in order to obtain an optimum operating point. According to a feature, a first and a second thermoelectric units comprise the same number of thermoelectric modules, the second power supply unit receiving a voltage at least twice the maximum voltage that can be delivered to said first power supply unit . Thus, the second power supply unit can be selected in priority or by default as soon as the need for heat transfer exceeds a threshold, and deactivated in priority or by default when the need for heat transfer is below a threshold inferior. Such a threshold for example takes into account a temperature outside the room heated / refreshed by the heat pump. Of course, it can be provided several second thermoelectric units More generally, it is thus possible to expand the range of operating points that can be obtained without too much use too many thermoelectric units. According to one feature, the reversible thermoelectric heat pump comprises a device for reducing, at at least one of the thermoelectric units, the transfer of heat between the two heat exchange circuits in the heat exchange zone defined between two exchangers of a thermoelectric unit 25 not electrically powered. The device may comprise members reducing or cutting the circulation of heat transfer fluid in the thermoelectric units. Alternatively, an actuator may be provided to modify the thermal conductivity to lower the thermal conductivity of the interface between the heat transfer fluid and the exchange surface, the actuator for example to separate the heat exchange zones of the thermoelectric modules. According to another feature, each of the thermoelectric units comprises: a first exchanger with a circuit part belonging to one of said two circuits; a second exchanger with a circuit part belonging to the other of said two circuits; and at least one valve motor adapted to selectively cut the coolant circulation in said circuit portions of the thermoelectric unit. Thus, it is possible to avoid circulating the heat transfer fluid unnecessarily in circuit parts that are not activated by the control device. Two motor-valves can be provided per thermoelectric unit. The valve motor (s) can thus advantageously form the device for reducing the heat transfer. Another object of the present invention is to propose a method of controlling a reversible thermoelectric heat pump making it possible to adapt the level of electrical consumption to the actual needs in heat transfer.

For this purpose, there is provided a method of controlling a reversible thermoelectric heat pump, in which a heat transfer fluid is circulated in two heat exchange circuits of a reversible thermoelectric heat pump which comprises a plurality of heat exchangers. thermoelectric heat transfer units each comprising a predetermined number of thermoelectric modules adapted to transfer heat between the two circuits, the method comprising the steps of: substantially connecting the heat pump to a source of electric power; supplying from said electric power source said thermoelectric units by at least one power supply unit having a plurality of output connections; enter a temperature setpoint; delivering, by a set of temperature sensors, signals representative of characteristic temperatures of the two heat exchange circuits; and characterized in that it further comprises the steps of: setting, by a plurality of setting devices provided with switches, the voltage delivered by each of the output connections, wherein a plurality of predetermined voltage levels can be delivered at the level of at least a part of the adjusting devices, according to the state of the switches; and controlling the switching patterns of the switches to selectively supply at least a portion of the plurality of thermoelectric units, and secondly, selecting the predetermined voltage level supplying the powered thermoelectric units. According to one particularity of the process, the heat transfer between two exchangers of an electrically unpowered thermoelectric unit is reduced at least in a heating mode of the reversible thermoelectric heat pump. This lowering can be obtained by stopping a circulation of the coolant at one or more of the thermoelectric units, for example those which are not electrically powered. In the heating mode of the heat pump, this minimizes the adverse heat loss by entropy. Indeed, heat is diffused from the fluid flowing in the thermoelectric units not electrically powered to the ambient environment. Other features and advantages of the invention will become apparent from the following description of several embodiments, given by way of non-limiting examples, with reference to the accompanying drawings in which: FIG. 1 is a diagrammatic view of a control system of a reversible heat pump with several thermoelectric units, according to an embodiment of the invention; FIGS. 2 and 3 are diagrams illustrating an example of a thermoelectric unit that can be used in a heat pump according to the invention; Figure 4 shows a step diagram for determining an optimum heating mode; FIG. 5 represents the impact of the choice of the supply voltage of a thermoelectric module in order to obtain a high COP.

In the different figures, the same references designate identical or similar elements. FIG. 1 shows an embodiment of a control system 2 for managing Peltier Effect Cells (PECs) or thermoelectric modules 3 for heat transfer. The control system 2 has a power supply unit 10, corresponding here to a modular system with multiple DC outputs, connected for example to a source of alternating current typically 230V. Several modular systems with multiple DC outputs can also be used. The thermoelectric modules 3 are arranged in groups of six in thermoelectric units 41, 42, 43, 44 respectively which define a heat exchanger system 4 of the heat pump. Of course, the number of thermoelectric modules 3 is not fixed and can be variable, for example and not limited to between two and ten per thermoelectric unit 41, 42, 43, 44. While the thermoelectric units 41, 42 , 43, 44 shown in Figure 1 comprise thermoelectric modules arranged in a single series 30, it should be understood that this assembly is only one option among others. Thus, it is also possible to use, alternatively or in combination with the thermoelectric units 41, 42, 43, 44, thermoelectric modules 3 arranged differently or other kinds of thermoelectric units 40 as illustrated in FIG. thermoelectric unit 40 shown in FIG. 2 differs from the thermoelectric units 41, 42, 43, 44 in that it has two series 30 'of three thermoelectric modules 3, each connected to two similar outputs Sa, Sb of the unit power supply 10 of the heat pump. The number of so-called cold plates may in this case be two per thermoelectric unit 40. At each of the outputs Sa, Sb of the power supply unit 10 may be associated with a rectified low-voltage supply circuit. The power supply unit 10 thus delivers a rectified current in full alternation with an optimized power. The frequency obtained may be of the order of 100 Hz for example. It is understood that each of the thermoelectric units 41, 42, 43, 44 shown in Figure 1 could be replaced by the thermoelectric unit 40 shown in Figure 2, with an adaptation (it may be a simple doubling) of the corresponding rectified low-voltage supply circuit, present in the power supply unit 10. The heat pump uses at least one circulation of a coolant (s) such as water. Referring to Figure 3, the thermoelectric unit 40 comprises a first exchanger 40a and a second exchanger 40b located above the first. The respective heat transfer fluids circulate in channels to ensure heat exchange with the flat outer face of the corresponding exchanger 40a, 40b. The first exchanger 40a has a fluid inlet E1 located on the right side of the thermoelectric unit 40 and an oppositely arranged output 01. The second exchanger 40b has a fluid inlet E2 on the left side and an opposite outlet 02. This second exchanger 40b, with its exchange face facing downwards, may be identical in all respects to the first exchanger 40a. A motor-valve V1 makes it possible to stop the circulation of the first fluid in the first exchanger 40a and a motor-valve V2 makes it possible to stop the circulation of the second fluid in the second exchanger 40b. FIG. 3 thus illustrates the use of motor-valves V1, V2, each adapted to selectively cut the heat-transfer fluid circulation in circuit portions of a thermoelectric unit 40. Naturally, any type of valve can be used, preferably with an organ control of the opening / closing of the valve flap. Here, the motor-valves V1, V2 are each adapted to close the fluid communication with the exchanger 40a, 40b. It is understood that the circulation of the first and second fluids can, however, continue through other parts of a circuit. This can be achieved for example by using motor-valves V1, V2 which interrupt or short circuit only a sinuous circulation in the exchanger 40a, 40b, while a longitudinal or external circulation to the exchanger 40a, 40b is allowed. Although FIG. 3 refers to the example of the thermoelectric unit 40, any one and preferably several of the thermoelectric units 41, 42, 43, 44 may be similarly equipped with at least one valve motor. The advantage of short-circuiting circuit parts formed at the level of the thermoelectric units 40, 41, 42, 43, 44 is to satisfy as closely as possible the specific needs parameterized for the heat pump, with an optimization of the COP, in particular when in a dwelling or similar room equipped with the heat pump, the heat transfer needs vary from one place to another. The motor-valves V1, V2 are closed in particular when there is no particular need for heat transfer by the corresponding heat exchange circuit. The closing of the motor-valves V1, V2 is advantageous in the heating mode of the heat pump, in order to avoid thermal coupling between the faces of the thermoelectric modules 3 that are not powered, and therefore heat exchanges in the opposite direction to those desired. These entropy losses of the exchanger system can thus be avoided.

More generally, the heat pump may be equipped with any means for varying, at one or more of the thermoelectric units 40, 41, 42, 43, 44, a heat transfer coefficient between the two heat exchangers 40a, 40b. In heating mode, a device provided with motor-valves V1, V2 or arranged differently thus makes it possible to modify the heat exchange conditions so as to lower the overall thermal conductivity. In the cooling mode, the entropic effect is favorable since one seeks to evacuate heat from the ambient environment. Therefore, it is possible to use a thermal coupling / decoupling device configured to stop the heat-dissipating hydraulic circulation and / or locally increase the thermal resistance by other known means, in the heating mode, and to circulate the heat transfer fluid. and / or locally lowering the thermal resistance by any other known means, in the cooling mode. The heat pump may be particularly suitable for low temperature heating and cooling applications for the home. The heat pump may be in the form of a housing or apparatus with a front panel control panel (not shown). A control interface 6 and the exchanger system 4 are for example arranged in the housing. The heat pump is typically intended for heating residential or professional premises, but also to cool these premises through the use of thermoelectric modules 3. The thermoelectric heat pump is therefore preferably reversible. Several rooms of a living space can be heated, respectively refreshed, using heat exchange loops connected to the housing. The living quarters in question are typically single-family dwellings ranging from a few-room apartment to a single-family house. The power is typically provided between three and thirty kilowatts of maximum heating power, without the latter value is an upper limit. The circulation of heat transfer fluid (s) is carried out through pipes in thermal contact with the faces of the same type of thermoelectric modules of the same type. It is understood that the heat transfer between the two circuits can be achieved using any suitable heat transfer circuit configuration. Whatever the configuration adopted, the face of the thermoelectric module 3 which pumps heat is typically at a temperature colder than the face which evacuates heat. A set temperature can be entered via a programming module or comparable device of the heat pump, which module is for example connected to the control interface 6 and is part of the control device. The temperature of the face of the thermoelectric module 3 which pumps heat and the set temperature form a pair of parameters that are decisive for obtaining a maximum coefficient of performance (COP). Indeed, there is an optimum DC supply voltage for which a thermoelectric module 3 has a maximum COP. This is valid both in the heating mode and in the cooling mode. In the present case, the supply current is preferably a full-alternating rectified alternating current. To approach the maximum COP, the optimum DC voltage is multiplied by a correction coefficient in order to determine the amplitude of the corresponding AC voltage. For example, for a sinusoidal alternating current, the optimum DC voltage is multiplied by a coefficient equal to I2. The thermal heating requirement is used here as a reference to determine the number of PECs or thermoelectric modules 3 required in the heat pump because this need is greater than that of the cooling thermal requirement, which would result in a smaller and therefore insufficient number of PELs. for heating.

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Referring to Figure 1, there is shown a control diagram of the thermoelectric units 41, 42, 43, 44 of the heat pump. The control system 2 comprises a connection 7 to an electric power source 8 and a power supply unit 10 adapted to supply said thermoelectric units 41, 42, 43, 44 from the electric power source 8. Here, the electric power source 8 provides an AC power supply. In this case, the current source can then be the urban network (at 230 V as is the case in many European countries in particular). Several protection fuses F are provided in the power supply unit 10. The number of thermoelectric modules 3 shown is twenty-four in the example illustrated in FIG. 1, but this number may of course be different, for example greater than to meet the heating power requirements. Here it is intended to choose an operating point adapted to obtain the desired temperature in similar living quarters or premises, the operating point chosen being that which corresponds to the optimal coefficient of performance (COP). In order to optimize this COP coefficient, whatever the point of operation of the heat pump (this operating point varies with the temperature of the heat transfer fluid (s) and the thermal power of heating or cooling), the control system 2 can select from one of a plurality of heating modes obtained by an adjustment of the power supply unit 10. In other words, a wide range of heating modes is provided which can cover the variety of thermal needs in a dwelling or similar room, these modes being distinguishable relative to each other by a different number of active thermoelectric modules 3 and / or a supply voltage U1, U2, U3 , U4 differs across the thermoelectric units 41, 42, 43, 44. In the non-limiting embodiment of Figure 1, the power supply unit 10 has several outgoing connections e S1, S2, S3, S4 for transmitting a supply voltage to each of the thermoelectric units 41, 42, 43, 44. Here to maximize the COP associated with each of the thermoelectric modules 3, it is provided in association with the device 20. The control device comprises an electronic control unit ECU connected to the control interface 6 and making it possible to modify the state of the switches of the switching device 20. The control device and the unit power supply 10 can be formed in respective housings connected to each other.

In the example of FIG. 1, the configuration of the switching device 20 can be modified in various ways while remaining in a heating mode according to, on the one hand, the state of switches C01, CO2, CO3, C04 of selecting the thermoelectric units 41, 42, 43, 44 respectively, and secondly, the state of switches C11, C12, C21, C22 for selecting the supply voltage level in two of the thermoelectric units. In particular for these two thermoelectric units 41, 42, the supply corresponds to a rectified low-voltage alternative. A full wave rectification bridge 51, for example in the form of a diode bridge, is here mounted between the output connection S1 and the two outputs defined by a transformer Ti or analog converter for adjusting the voltage. The transformer Ti makes it possible to deliver a voltage which is a function of the state of the switches 11, 12 of the switch C11. Servo feedback with the C11 switch can be implemented through a collection of information representative of a heating need by the electronic control unit ECU. Here, the information representative of the heating need is for example one or more characteristic temperatures of the two heat exchange circuits and the set temperature. Such a control is for example present for each of the thermoelectric units 41, 42, 43, 44. In the embodiment of FIG. 1, the switching device 20 comprises switches C01, CO2, CO3, C04, C11, C12, C21, C22 each comprising several switches. This kind of switching device 20 is simple to operate because it is not necessary to make a fine and progressive adjustment of the current or voltage delivered. Although the embodiment of Figure 1 provides a switching device 20 adapted to adjust output voltages U1 and U2 by switches C11, C12 each placed on the side of the secondary windings, between a transformer T1, T2 of voltage-down type and full-wave rectification bridge 51, 52 associated, any other suitable configuration can be used. For example, in a less preferred embodiment, the voltage-reducing type transformers T1, T2, or the like, may alternatively or in a complementary manner be provided with switches which are adapted to short-circuit a number of turns of the primary windings. transformer T1, T2. The output connections S3, S4 may each be associated with a current-reversing device, for example located at the output of the transformer 53, 54 respectively associated with the output connection S3, S4. This inverter device can be actuated by the control device. The reversible nature of the power supplied to the thermoelectric units 43, 44 makes it easy to switch from the heating mode to the cooling mode. At least for one of these thermoelectric units 43, 44 with supply reversal, it is possible to provide a greater heating power. Here switches C13, C14 in connection with the electronic control unit ECU are provided to allow the current reversal. The refresh mode may correspond to the closing of the switches 14 of the corresponding switch C13, C14 (the switches 13 being in an open state). Less power can also be obtained by using only one of the outputs S3, S4 to selectively supply one or the other of the thermoelectric units 43, 44. In the example of FIG. 1, to each of the rectifying bridges double alternation 51, 52 corresponds to an output S1, S2 defined by two junctions of the rectifier bridge. The switching device 20 comprises at least one switch C11, C12 configurable according to two positions or modes. One of these modes (11 = 0 and 12 = 1), corresponding to the case of FIG. 1, makes it possible to deliver a first voltage with the four terminals at the output of the transformer T1, T2 or equivalent converter connected to two bridge junctions. 51, 52. The other of these modes (11 = 1 and 12 = 0) makes it possible to deliver a second voltage higher than the first voltage with two of the four terminals at the output of the converter connected to two junctions of the bridge. recovery. With reference to FIG. 1, the converter or converters, here formed by the transformers Ti, T2, have two outputs defined by four terminals. Two predetermined voltage levels, each much lower than the voltage level of the electric power source (8), are delivered at these outputs. In this nonlimiting example, it is the state of the switches C11, C12 of the switching device 20 that select respectively a predetermined output voltage level resulting from a combination between the two predetermined levels delivered by a converter.

FIG. 1 shows a configuration of the switching device 20, in which the electronic control unit ECU controls a power mode which uses only two of the power supply circuits, thanks to the switches C01, CO2. It is understood that from the point of view of the ECU control unit, simple all or nothing commands can be used to parameterize the configuration of the switching device 20. In other words, the pump has a control device adapted to configure the switching device 20 , so as to selectively activate the thermoelectric units 41, 42, 43, 44. In addition, at least one of the thermoelectric units 41, 42, 43, 44 can be supplied with different non-zero voltage levels, taking into account the structure of some of the power supply circuits present in the power supply unit 10. Thus, the control device also makes it possible to select a predetermined voltage level from among several voltage levels. The following example illustrates, in connection with the embodiment of Figure 1, the variety of power modes that can be selected for the heat pump. The ECU electronic control unit of the control device here provides on / off output commands for configuring the respective switches 10, 11, 12 of the power supply circuits associated with the thermoelectric units 41, 42, as well as the respective switches 10, 13, 14 of the power supply circuits associated with the thermoelectric units 41, 42. On-off output controls are also provided by the electronic control unit ECU for setting the status of the motor-valves associated with the thermoelectric units 41, 42 , 43, 44. This state is referenced V in the following table, with V = 1 meaning that the corresponding valve or valves are open.

Uses of two thermoelectric units 41, 42 in six modes of heating power supply

First Unit First Two First Two Two Two Units Units Units Units Units 14A / 35VAC 14A / 35VAC 7A / 70VAC 7A-14A 7A / 70VAC 220VAC 10 1 1 1 1 1 0 11 0 0 1 1 1 0 12 1 1 0 0 0 0 V 1 1 1 1 1 0 Second Unit First Two First Two Two Two Unit Units Unit Units Units 14A / 35VAC 14A / 35VAC 7A / 70VAC 7A-14A 7A / 70VAC 220VAC 10 0 1 0 1 1 0 11 0 0 0 0 1 0 12 0 1 0 1 0 0 V 0 1 0 1 1 0 The two tables above illustrate the selection of the different power modes according to the on-off commands of the electronic control unit ECU. FIG. 1 illustrates the mode of supply in which there are two thermoelectric units 41, 42 which are supplied at 35 VAC / 14 A (see column in bold), while the other two thermoelectric units 43, 44 are not powered. Conversely, in the sixth mode of supply indicated in the tables above, only the thermoelectric units 43, 44 are powered with 220V.

Uses of the last two thermoelectric units 43, 44 in the six heating mode power supply modes Last two units First Two First Two Two two units Unit units Units Units 14A / 35VAC 14A / 35VAC 7A / 70VAC 7A-14A 7A / 70VAC 220VAC 10 0 0 0 0 0 1 13 0 0 0 0 0 1 14 0 0 0 0 0 1 V 0 0 0 0 0 1 It may be noted that an inversion of the supply current is permitted for these two thermoelectric units 43, 44 For example, closing the switches 13 by leaving the switches 14 open can provide a power supply suitable for a heating mode, while the reverse setting provides a refresh mode. Here, the output connections S3, S4 are each associated with an inverter device of the direction of the current that can be actuated by the electronic control unit ECU of the control device. Naturally, such an inverter device may be used for any of the output connections S1, S2, S3, S4 of the power supply unit 10 and may more generally be in any suitable form. The switching device 20 may comprise switches C11, C12 varying the supply voltage level by a factor of two or greater by two at the respective output connections S1, S2. Of course, the feeding modes presented above are only examples that can be completed and / or replaced by other feeding modes. The control device has a conversion table or similar means associating with the pair of first thermoelectric units 41, 42 a determined number of commands which here differ from each other by the following two selected parameters: the state, representative selecting all or part of a thermoelectric unit 41, 42, switches C01, CO2 of the switching device 20 which are arranged between the electric power source 8 of the transformers Ti, T2; and the state, representative of a selection of a voltage level, of the switches C11, C12 of the switching device 20. For the choice of the output controls, the electronic control unit ECU can use different inputs analogical, for example supplied using first temperature sensors 31 and second temperature sensors 32. The first sensors 31 deliver for example signals representative of the characteristic temperatures of the two heat exchange circuits, such as the temperatures of starting and returning of the heat transfer fluid in the emitter circuit, the flow and return temperatures of the coolant in the external circuit. The second temperature sensors 32 make it possible to measure the temperature outside the dwelling or similar room equipped with the heat pump, as well as the ambient temperature of the dwelling. More generally, the set of temperature sensors 31, 32 is provided to provide sufficient information for an estimation of the conditions in which the heat transfer is carried out. The electronic control unit ECU also receives digital on-off inputs in a preferred embodiment, which may correspond to at least one of the following commands: - Control of starting of the heat pump, with example a power up of the PLC (this order is typically manual and given by the user by pressing a button on the front); - Heating mode start command (this order is also typically manual); - Start command of the refresh mode (this order is also typically manual); and - The order of heating or cooling by the room thermostat as a function of the temperature difference between the room temperature and the set point in the dwelling. A CAN converter from the ECU electronic control unit is used to collect the different inputs. The exploitation of the corresponding information can be performed at the electronic control unit ECU of the control device. It is understood that the temperature setpoint (it may be a desired ambient temperature) indicated by the user is taken into account so as to determine the temperature that should be reached in the heat transfer fluid circuits to meet the user's request. The knowledge of the overall heat resistance of the exchanger and preferably the external temperature and the overall thermal resistance of the habitat can allow a correlation between a set temperature set directly by a user and the actual need for heat transfer. Thus, servocontrol of a parameter representative of the heat transfer requirement, for example an average water temperature obtained from the temperatures measured by two of the sensors 31, can be implemented by using a corresponding setpoint parameter. . This setpoint parameter takes into account the setpoint temperature set by the user. In one embodiment of the invention, the difference between the reference parameter and the corresponding parameter estimated in real time is calculated by using the measurements of the sensors 31, 32. An algorithm of the ECU electronic control unit is provided. to perform this calculation and perform a correlation, according to said temperature setpoint and the signals delivered by all the first and second temperature sensors 31, 32, between heat transfer requirements and a single optimum operating point. For this, calculating the deviation from the setpoint parameter allows the room thermostat to deliver the heating or cooling command.

In the example of FIG. 1, which corresponds to a mode of operation by heating using the two thermoelectric units 41, 42, the operating point has thus been determined using the control unit algorithm. ECU electronics to maximize the coefficient of performance of the heat pump. In a nonlimiting manner, the algorithm typically calculates in this case two parameters such as the heating power and the average water temperature of that of the circuits which is heat emitter. This pair of parameters makes it possible, for example by using a correspondence table, to find the number of thermoelectric modules 3 optimal for the need as well as the optimal current for these thermoelectric modules 3. The choice of the power supply mode is then in the configuration that is closest to the optimization parameters thus determined. It is understood that the number of thermoelectric modules 3 in operation can advantageously evolve dynamically to meet a large number of pairs (amount of heat for heating / average temperature of the water of the emitter circuit) and (amount of heat for the cooling / average water temperature of the transmitter circuit). Since this torque varies as a function of time and the design of the overall system integrating the heat pump, the process of determination by the algorithm of the number of thermoelectric modules 3 in operation must be repeated regularly, with a simultaneous determination of the mode of operation. optimal supply of this determined number of modules 3 which satisfies the real need for the minimum power consumption. The electronic control unit ECU shown in FIG. 1 may comprise a parameterization module for setting a defined number of predetermined operating points of the heat pump, so as to define different configurations each in order to better correspond to a specific need. in heat transfer. The operating points are parameterized by the parameterization module as a function, on the one hand, of a number of thermoelectric modules 3 which are activated, and on the other hand of supply voltages each associated with the thermoelectric modules 3 which are enabled.

With reference to FIG. 5, it will be understood that increasing the supply voltage assigned to each thermoelectric module tends to lower the COP. That is why the control device can advantageously configure the switching device 20 so as to select a heating mode with a number of thermoelectric modules 3 sufficient to meet the needs for heat transfer, and to deliver a sufficient supply current just to optimize the COP. For a pair of temperature measurements in the two circuits, there is a single supply current for which a thermoelectric module 3 considered has a maximum COP. In other words, it is possible to associate at such a point of operation a single pair of heat flows for the heat transfer in the two circuits transmitter and receiver of heat. FIG. 5 thus shows that there is an optimum operating point as a function of the power required for the PC heating required for different setpoint temperatures PC (20), PC (25) and PC (30). The corresponding COP curves COP (20), COP (25) and COP (30) are indicated in connection with the ordinate axis on the left in Figure 5. This kind of modeling called "water law" in the case where the heat transfer fluid is water allows to find the optimum supply voltage of the thermoelectric modules 3 according to the power requirements. With reference to FIG. 4, the heat pump can be controlled by proceeding as follows: the heat pump is connected in a preliminary step to the electric power source 8; in a first parameterization step 61, at least one temperature setpoint is programmed; after the measurement step 62, the temperature sensors 31, 32 transmit signals representative of the characteristic temperatures of the two heat exchange circuits; the thermoelectric units 41, 42, 43, 44 are supplied from the electric power source 8 by the power supply unit 10; regulating the voltage delivered at each of the output connections S1, S2, S3, S4 of the power supply unit 10; during a step 63 for determining the heat transfer requirements, the algorithm of the electronic control unit ECU is used and is calculated as a function of the temperature setpoint and the signals delivered by the set of temperature sensors 31 Parameters representative of a heat transfer requirement (which may include heating or cooling power and a characteristic temperature in the emitter circuit of such heating or cooling); in a step 64 implemented by the algorithm of the electronic control unit ECU, the number of thermoelectric modules 3 is determined as well as an optimum supply current of these thermoelectric modules 3; in a selection step 65, selecting a configuration of the switching device 20 as a function of the previous step 64 (i.e. in correspondence with the selected operating point); and the power supply of the thermoelectric units 41, 42, 43, 44 is then controlled by using the supply voltage levels of the thermoelectric modules 3 which make it possible to reach or approach as close as possible to the optimal COP for each of the thermoelectric modules 3.

One of the advantages of the invention is to provide the operator with a means of optimizing the power consumption of the heat pump while using thermoelectric modules 3 which may be identical. The optimization is automated to ensure efficient operation of the heat pump. The speed of response and the flexibility of the control system (2) are also advantages of such a heat pump. The power supply unit 10 may be relatively compact so as to be integrated with a microcontroller in a single control unit of the heat pump. It is understood that the voltage control devices provided in the power supply unit 10 may be in different forms from those shown in Figure 1, to provide several separate voltages, each assigned to one of the thermoelectric units 41, 42, 43, 44. One or more electrical connectors may be provided with control links to enable the power supply unit 10 to be connected to the control device of the heat pump. In this case, the control connections of the electrical connector enable the selective activation of each of the thermoelectric units 41, 42, 43, 44, as well as the selection of the configurations of the switching device 20. It must be obvious to the persons versed in the The present invention allows embodiments in many other specific forms without departing from the scope of the invention as claimed. It is understood in particular that the control system 2 is not limited to the particular examples described with reference to FIGS. 1 and 2 and can use different types of servocontrol means for controlling a switching device 20, depending on signals and or data representative of one or more setpoint temperatures and one or more measured temperatures.

The power supply unit 10 may be in various forms and may have physically separate power supplies and / or be connected to a plurality of power sources. For example, it is possible to use, depending on the operating conditions, at least one current of an urban network and / or the current supplied by additional equipment with photovoltaic cells or converting into electricity an external energy. Furthermore, the thermal coupling / decoupling between the sources supplying the exchangers of the thermoelectric units 41, 42, 43, 44 may be used in a heat pump only in combination with the selective supply of these thermoelectric units 41, 42, 43 , 44. In such an embodiment, the adjustment of the voltage delivered by each of the output connections S1, S2, S3, S4 is therefore optional and can be suppressed. In this case, even in the absence of voltage level adjustment functions, it is advantageous to obtain a heat pump at a lower cost and making it possible to adapt effectively to the needs while approaching a point of operation. optimal: the control device allows a selective setting of the number of thermoelectric modules 3 and activates a suitable configuration of the thermal coupling / decoupling device associated with the thermoelectric units 40, 41, 42, 43, 44.

Claims (14)

REVENDICATIONS1. A control system (2) of a reversible thermoelectric heat pump having two heat exchange circuits using a heat transfer fluid, and a plurality of heat transfer thermoelectric units (40, 41, 42, 43, 44) comprising each a predetermined number of thermoelectric modules (3) adapted to transfer heat between the two circuits, the control system comprising: a power supply unit (10) for connection to a power source (8) and having a plurality of output connections (S1, S2, S3, S4) for supplying a supply voltage to each of the thermoelectric units; a set of temperature sensors (31, 32) adapted to deliver in particular signals representative of characteristic temperatures of the two heat exchange circuits; and a control device (6, ECU) connected to an input device of a set temperature for controlling the power supply of the plurality of thermoelectric units according to said temperature setpoint and the signals delivered by said set temperature sensors (31, 32); characterized in that the power supply unit (10) comprises a plurality of voltage regulating devices provided by each of the output connections (S1, S2, S3, S4), said setting devices comprising switches, at at least a part of the adjusting devices being adapted to deliver a plurality of predetermined voltage levels according to the state of the switches of said adjusting device, and in that the control device is connected to the switches and adapted to control different switching configurations of the switches for on the one hand, selectively supplying at least a portion of the plurality of thermoelectric units (40, 41, 42, 43, 44), and on the other hand, selecting the predetermined voltage level supplying the powered thermoelectric units. 2. Control system according to claim 1, wherein the control device (6, ECU) comprises an electronic control unit (ECU) which comprises: a parameterization module for setting a defined number of predetermined operating points of the heat pump, each operating point corresponding, on the one hand, to a number of thermoelectric modules (3) supplied, and on the other hand, to a predetermined supply voltage for each of the thermoelectric units (40, 41, 42, 43, 44) powered; and an algorithm adapted to perform a correlation, as a function of said temperature setpoint and the signals delivered by said set of temperature sensors (31, 32), between heat transfer requirements and a single operating point, so as to choose the operating point that maximizes the heat pump's coefficient of performance. 3. Control system according to one of claims 1 and 2, wherein the control device (6, ECU) comprises a conversion table for associating with a first of the voltage adjusting devices and a second of the devices for adjusting the voltage, a determined number of configuration commands which differ from each other by at least one, and preferably two, of the following selected parameters: the state, representative of a selection of all or part of a thermoelectric unit, first switches (C01, CO2) which are arranged between the electric power source (8) and said first and second voltage control devices; and the state, representative of a selection of a voltage level, of second switches (C11, C12) arranged at the first and second voltage control devices. 4. Control system according to one of claims 1 to 3, wherein the electric power source (8) provides an AC power supply and said adjusting devices comprise: at least one converter (T1, T2) with two outputs defined by four terminals, adapted to deliver two predetermined voltage levels each much lower than the voltage level of the electric power source (8); and switches (C11, C12) arranged at the output of the converter for providing a predetermined output voltage level resulting from a combination of said two predetermined levels output by the converter. 5. Control system according to claim 4, wherein said adjusting devices comprise a full-wave rectifier bridge (51, 52) and an output defined by two junctions of the rectifier bridge (51, 52), at least one of the switches (C11, C12) being configurable according to two positions, one of which makes it possible to deliver a first voltage by using four terminals at the output of the converter (T1, T2) connected to two junctions of the rectifier bridge (51, 52), and another provides a second higher voltage than the first voltage by using only two of the four terminals at the output of the converter (T1, T2) connected to two junctions of the rectifier bridge (51, 52). The control system according to any one of claims 1 to 5, wherein the power supply unit (10) comprises: first output connections (S1, S2) with power adjustable in an adjustable manner according to the configuration of the switches; and second output connections (S3, S4) with predefined power regardless of the configuration of the switching device (20). A control system according to claim 6, wherein the controller (6, ECU) comprises a conversion table for using either one or more of the first output connections (S1, S2) or one or more second output connections (S3, S4). 8. Control system according to one of claims 6 and 7, wherein the second output connections (S3, S4) are each associated with an inverter device (13, 14) of the direction of the current operable by the control device ( 6, ECU). A reversible thermoelectric heat pump comprising two heat exchange circuits using a heat transfer fluid and a plurality of thermoelectric heat transfer units (40, 41, 42, 43, 44) each comprising a predetermined number of thermoelectric modules. (3) adapted to transfer heat between the two circuits, characterized in that it comprises the control system (2) according to one of claims 1 to 8. The reversible thermoelectric heat pump according to claim 9, wherein a first one of the thermoelectric units (40) comprises two series (30 ') of thermoelectric modules (3), each of the two series being fed independently of one another. by one of the output connections (S1, S2, S3, S4) of the power supply unit. A reversible thermoelectric heat pump according to claim 9 or 10, comprising a device for reducing, at at least one of the thermoelectric units (40, 41, 42, 43, 44), the heat transfer between the two circuits. exchange of heat in the heat exchange zone defined between two exchangers of a thermoelectric unit not electrically powered. The reversible thermoelectric heat pump of claim 11, wherein each of the thermoelectric units (40) comprises: a first exchanger (40a) with a circuit portion belonging to one of said two circuits; a second exchanger (40b) with a circuit portion belonging to the other of said two circuits; and at least one valve motor (V1, V2) adapted to selectively cut the coolant circulation in said circuit portions of the thermoelectric unit, said motor valve forming the heat transfer reduction device. 13. A method of controlling a reversible thermoelectric heat pump, in which a heat transfer fluid is circulated in two heat exchange circuits of a reversible thermoelectric heat pump which comprises a plurality of thermoelectric units (40, 41). , 42, 43, 44) each comprising a predetermined number of thermoelectric modules (3) adapted to transfer heat between the two circuits, the method comprising the steps of essentially: connecting the heat pump to a heat pump; electric power source (8); supplying from said electric power source said thermoelectric units (40, 41, 42, 43, 44) by at least one power supply unit (10) having a plurality of output connections (Si, S2, S3, S4, S5); enter a temperature setpoint; delivering, by a set of temperature sensors (31, 32), signals representative of characteristic temperatures of the two heat exchange circuits; and characterized in that it further comprises the steps of: adjusting, by a plurality of adjusting devices provided with switches, the voltage delivered by each of the output connections (Si, S2, S3, S4), several voltage levels predetermined ones that can be delivered at at least a portion of the adjusters, depending on the state of the switches; and controlling the switching patterns of the switches to selectively supply at least a portion of the plurality of thermoelectric units (40, 41, 42, 43, 44), and secondly select the voltage level predetermined supply to the thermoelectric units supplied. 14. The control method as claimed in claim 13, wherein the heat transfer between two exchangers of a thermoelectric unit (40, 41, 42, 43, 44) which is not electrically powered is reduced, at least in a heating mode of the reversible thermoelectric heat pump, preferably by stopping a circulation of the coolant at said thermoelectric unit not electrically powered.