Device for producing and using a heat transfer fluid in a closed circuit

Abstract

The invention relates to a device for producing and using a heat transfer fluid in a closed circuit according to operating cycles, the device comprising: - a buffer tank (1) comprising two compartments, a recovery compartment (2a) and a storage compartment (2b), separated by a flexible membrane (3); - a consumption unit (7), configured to extract heat or cold from the heat transfer fluid; and - a unit (9) for regenerating the heat transfer fluid, configured to supply heat or cold to the heat transfer fluid, characterised in that the device comprises a control member (10), the control member (10) comprising: - means for obtaining a forecast (11) of the energy requirements of the consumption unit; - search means configured to take the forecast (11) into account and to determine an optimal control strategy for the regeneration unit (9).

Description

[0001] DESCRIPTION

[0002] Title: Device for producing and using a heat transfer fluid in a closed circuit

[0003] Technical field

[0004] The present invention relates to the field of production and use of a heat transfer fluid. More particularly, it relates to a device for optimizing the production of thermal or cooling energy according to consumption needs.

[0005] The invention finds a particularly advantageous application for achieving energy savings.

[0006] Prior art

[0007] When a system uses a heat transfer fluid as a vector for thermal or cooling energy, it is known to use a buffer tank. The buffer tank allows the heat transfer fluid to be stored at a certain "hot" or "cold" temperature, with a view to injecting it into a consumption circuit. The consumption circuit may correspond, for example, to a circuit comprising radiators to heat a home or a circuit comprising heat exchangers to cool a room, for example a cold room.

[0008] The buffer tank therefore allows a temporal decorrelation, at least partial, of the production of the heat transfer fluid and its use.

[0009] After the heat transfer fluid has been used to provide thermal or cooling energy, the thermal power of the heat transfer fluid is reduced. The thermal fluid is then "lukewarm",

[0010] - either because the heat transfer fluid is initially “hot” so that its temperature has decreased after circulation in the consumption circuit,

[0011] - either because the heat transfer fluid is initially “cold” so that its temperature has increased after circulation in the consumption circuit.

[0012] Two solutions are then possible.

[0013] The "warm" heat transfer fluid can be reinjected directly into the buffer tank, which has the disadvantage of reducing the thermal power of the entire heat transfer fluid in the tank, either by reducing the temperature of a "hot" heat transfer fluid, or by increasing the temperature of a "cold" heat transfer fluid.

[0014] Alternatively, thermal power can be reinjected into the "warm" heat transfer fluid, i.e. the "warm" heat transfer fluid can be heated or cooled before being reinjected into the buffer tank. In this case, the "warm" heat transfer fluid can be stored before and / or after heating or cooling in one or more intermediate storage tanks, which has the disadvantage of increasing the size of the installation. In the absence of an intermediate storage tank, the "warm" heat transfer fluid must be heated or cooled at a flow rate equivalent to the outlet flow rate of the buffer tank, which requires significant sizing of the heat transfer fluid regeneration unit. This regeneration unit can typically be a heat pump or a cooling unit.

[0015] In order to provide a solution to these drawbacks, document DE3115988 proposes a buffer tank comprising a flexible membrane, separating a preheated liquid and a hot liquid. However, the solution presented in this document does not allow the energy requirements of the installation to be taken into account, in order to optimally control the inlets and outlets of the buffer tank and the heat transfer fluid regeneration unit.

[0016] Documents US4182489 Al and ITG020100007 Al propose systems comprising tanks with compartments separated by a flexible membrane, but these solutions also do not allow for taking into account the future needs of the system, and therefore do not allow for optimal control.

[0017] The technical problem of the invention is therefore to be able to take into account the forecast needs in thermal or cooling energy to control an installation in an optimal way, which makes it possible to save energy and to use an installation sized as best as possible according to needs.

[0018] Statement of the invention

[0019] The present invention aims to address this technical problem by using a device for producing and using a heat transfer fluid in a closed circuit according to operating cycles, the device comprising:

[0020] - a buffer tank comprising two compartments, a recovery compartment and a storage compartment separated by a flexible membrane, said buffer tank comprising an inlet and an outlet connected to the recovery compartment, and an inlet and an outlet connected to the storage compartment,

[0021] - a fluid consumption circuit, extending between the outlet of the storage compartment and the inlet of the recovery compartment of the buffer tank,

[0022] - at least one unit for consuming calories from said heat transfer fluid, configured to extract, for a predetermined duration less than the duration of an operating cycle, calories or frigories from the heat transfer fluid at the level of the consumption fluid circuit, - a regeneration fluid circuit, extending between the outlet of the recovery compartment and the inlet of the storage compartment of the buffer tank, and

[0023] - at least one controllable heat transfer fluid regeneration unit, configured to provide calories or frigories to the heat transfer fluid at the level of the regeneration fluid circuit.

[0024] This device is particular in that it comprises a control member for said at least one regeneration unit, said control member comprising:

[0025] - means for recovering a forecast of the energy requirements of said at least one consumption unit over time over the entire duration of an operating cycle;

[0026] - search means configured to take into account said forecast and determine an optimal control strategy for said regeneration unit in which the regeneration unit provides the required quantity of energy throughout the duration of the operating cycle; the control member being configured to apply said optimal control strategy to said regeneration unit.

[0027] Thanks to these provisions, the regeneration unit can be controlled in order to meet the needs of the consumption unit, while avoiding consuming more energy than necessary. Energy savings are thus achieved compared to existing systems. In addition, the device, and more specifically the power of the regeneration unit, can be sized by decorrelating the instantaneous power of the needs of the consumption unit in relation to its production, which makes it possible to avoid oversizing and to significantly optimize the installed power in regeneration.

[0028] The search means may be configured to take into account an estimate of the heat losses in the consumption fluid circuit when determining the control strategy, thereby improving the accuracy of the search for the optimal control strategy. In addition, the search means may be configured to take into account an estimate of the heat losses in the regeneration fluid circuit when determining the control strategy, thereby also improving the accuracy of the search for the optimal control strategy.

[0029] The search means can also be configured to take into account an estimate of the heat losses in the storage compartment of the buffer tank when determining the control strategy, this estimate taking into account the storage duration of the heat transfer fluid in the storage compartment, which further improves the accuracy of the search for the optimal control strategy.

[0030] Alternatively or in addition, the search means can be configured to take into account a forecast of changes in the outside temperature when determining the control strategy, which further improves the precision of the search for the optimal control strategy.

[0031] The device for producing and using a heat transfer fluid may include:

[0032] - a first volumetric meter, configured to measure the volume of heat transfer fluid passing through the inlet connected to the recovery compartment, and a second volumetric meter, configured to measure the volume of heat transfer fluid passing through the outlet connected to the recovery compartment, or

[0033] - a first volumetric meter, configured to measure the volume of heat transfer fluid passing through the inlet connected to the storage compartment, and a second volumetric meter, configured to measure the volume of heat transfer fluid passing through the outlet connected to the storage compartment, the control member being able to be configured to deduce from the data from said volumetric meters information on the filling of the recovery and storage compartments, and to take this information into account to apply said optimal control strategy to said regeneration unit, which makes it possible to know precisely the thermal power available in the buffer tank at any time.

[0034] The device for producing and using a heat transfer fluid may comprise a first pressure sensor, configured to measure the pressure within the regeneration compartment, and a second pressure sensor, configured to measure the pressure within the storage compartment, the data relating to the pressure differential being able to be used by the control member to detect the case where one of the compartments is considered empty, and the other compartment is considered full.

[0035] The device for producing and using a heat transfer fluid may comprise at least one temperature sensor configured to measure the temperature of the heat transfer fluid passing through the inlet connected to the recovery compartment, the control member being able to be configured to use the data from said temperature sensor to control the regeneration unit. Indeed, the information on the temperature entering the recovery compartment, combined with the volume data of these compartments, makes it possible to determine the power required to reach a target temperature in the storage compartment.

[0036] The buffer tank may have a cylindrical shape, closed by two domed bottoms, and the flexible membrane may extend from one domed bottom to the other. This arrangement allows each compartment to occupy in turn almost 100% of the total volume of the buffer tank, without the membrane having to have too large a surface area. Indeed, in the prior art, the flexible membranes are arranged perpendicular to the axis of the cylinder, which facilitates the management of the seal between the two compartments, but requires a more flexible membrane with a larger surface area, so that it can alternately fit the domed bottoms of the buffer tank when one of the compartments occupies almost the entire volume of the buffer tank. The movements of these membranes of the prior art are therefore greater, and present higher risks of membrane jamming and generation of dead volume in the buffer tank.

[0037] The membrane may comprise, over all or part of its perimeter, a cavity in which there is a plate capable of matching the internal edges of the buffer tank, the plate being fixed to the buffer tank so as to hold the membrane in position in the buffer tank, which allows the membrane to best match the internal shape of the buffer tank, and thus to obtain a satisfactory seal between the regeneration and storage compartments.

[0038] In the storage compartment, said heat transfer fluid can be in the state of superheated water, which makes it possible to store a large quantity of heat in a restricted volume.

[0039] The buffer tank may comprise two removable shells, and the flexible membrane is fixed between the two shells, which is a simple and effective way of producing a device according to the invention.

[0040] The buffer tank may include at least one position sensor capable of detecting the position of the membrane, which allows more precise control of the device.

[0041] The membrane may not be completely watertight, so that during operation of the device, unless one of the compartments is completely filled, the pressure difference between the recovery and storage compartments is less than 20 millibars.

[0042] The membrane can be configured so that the volume occupied by each compartment is variable over an interval comprising at least between 10 and 90% of the total volume of the buffer tank, which makes it possible to increase the flexibility of use of the device according to the invention.

[0043] The present invention also relates to a method of using a device according to the invention, comprising an operating cycle comprising the following steps:

[0044] - heating the heat transfer fluid in the regeneration circuit and storing the heat transfer fluid in the storage compartment, until a target quantity of heat transfer fluid to be stored is reached, this step being carried out over a first period of time; and

[0045] - sending the heat transfer fluid stored in the storage compartment to the consumption fluid circuit, this step being carried out for a second period of time less than said second period of time.

[0046] Thanks to these provisions, the power required for production can be lower than the power required for consumption, which makes it possible to use a less powerful regeneration unit for identical needs.

[0047] Said method may further comprise the following steps:

[0048] - real-time estimation of the volume of the regeneration and storage compartments by the control unit, taking into account the data from the first volumetric counter and the second volumetric counter,

[0049] - when the data from the first pressure sensor and the second pressure sensor show a pressure differential between the two compartments greater than a certain threshold, updating of the estimates of the volumes of the compartments, a compartment being considered as occupying a certain proportion of the volume of the buffer tank, said proportion being greater than or equal to 95%,

[0050] - real-time control of the regeneration unit by the control unit, using estimated compartment volume data and temperature sensor data.

[0051] Brief description of the drawings

[0052] The present invention and its advantages will appear better in the following description of several embodiments given as non-limiting examples, with reference to the appended drawings, in which:

[0053] [Fig 1] Fig. 1 is a schematic view of a device according to a preferred embodiment of the invention,

[0054] [Fig 2] Fig. 2 is a longitudinal sectional view of the buffer tank of a device according to one embodiment of the invention,

[0055] [Fig 3] Fig. 3 is a cross-sectional view of the buffer tank of Fig. 2, with three different positions of the flexible membrane, and

[0056] [Fig. 4] Fig. 4 is a sectional view of a method of attaching the membrane to the buffer tank according to a particular embodiment of the invention.

[0057] Description of the embodiments

[0058] The device according to the invention, illustrated in a preferred embodiment in fig. 1, makes it possible to produce and use a heat transfer fluid, in a closed circuit, according to operating cycles.

[0059] The heat transfer fluid is, for example, water, or water mixed with one or more additives, making it possible to modify its thermodynamic properties such as its phase change temperatures and / or its mechanical properties such as its viscosity. The choice of heat transfer fluid depends on the type of application, and in particular the temperatures at which it is used. In the device according to the invention, the heat transfer fluid can be used at constant pressure at all points of the device and not vary over time, or its pressure can vary according to the zones of the device and / or over time. The pressure(s) used can be atmospheric pressure, or pressures lower or higher than atmospheric pressure.

[0060] The expression "closed circuit", in the context of the present invention, designates the fact that the majority of the heat transfer fluid regularly flows through the entire circuit. This does not exclude the addition or withdrawal of certain quantities of heat transfer fluid at one or more points in the circuit, to compensate for possible losses, or to adjust the load of heat transfer fluid in the circuit as required.

[0061] The operating cycles of the device according to the invention correspond to cycles of calorie or frigory requirements of the system. These cycles correspond, for example, to the operating cycles of a machine consuming heat or cold, for example a machine requiring a certain quantity of thermal energy every hour for 5 minutes.

[0062] The device according to the invention comprises a buffer tank 1 comprising a recovery compartment 2a, and a storage compartment 2b, separated by a flexible membrane 3.

[0063] The buffer tank 1 has a first inlet 4a and a first outlet 5a, located at the recovery compartment 2a. The first inlet 4a, respectively the first outlet 5a, allows heat transfer fluid to pass between the exterior of the buffer tank 1 and the recovery compartment 2a, without passing through the storage compartment 2b.

[0064] Similarly, the buffer tank 1 has a second inlet 4b, and a second outlet 5b, located at the level of the storage compartment 2b. The second inlet 4b, respectively second outlet 5b, allows heat transfer fluid to pass between the exterior of the buffer tank 1 and the storage compartment 2b, without passing through the recovery compartment 2a.

[0065] The device according to the invention also comprises a consumption fluid circuit 6, extending between the second outlet 5b and the first inlet 4a, that is to say it is configured to transport the heat transfer fluid, from the storage compartment 2b, to the recovery compartment 2a. At the level of the consumption fluid circuit 6, the device according to the invention comprises at least one consumption unit 7. The consumption unit 7 is configured to extract calories or frigories from the heat transfer fluid, for a predetermined duration less than a duration of an operating cycle. This is for example a heat exchanger, controlled to regularly extract the energy necessary for the operation of a machine, or for maintaining at a certain temperature a space or a tank in which a product to be heated is located.

[0066] The device according to the invention also comprises a regeneration fluid circuit 8, extending between the first outlet 5a and the second inlet 4b, that is to say it is configured to transport the heat transfer fluid, from the recovery compartment 2a, to the storage compartment 2b. At the level of the regeneration fluid circuit 8, the device according to the invention comprises at least one regeneration unit 9. The regeneration unit 9 is configured to provide calories or frigories to the heat transfer fluid, so that they can be extracted by the consumption unit 7. The regeneration unit 9 may be a heat pump, a boiler, or any other means adapted to the particular application which is made of the invention.

[0067] The flexible membrane 3 makes it possible to vary the volumes of the recovery 2a and storage 2b compartments, the sum of these volumes being constant and corresponding to the useful volume of the buffer tank 1. Indeed, during an operating cycle of the device, the latter operating in a closed circuit, the maximum occupation of the recovery 2a compartment, respectively of the storage 2b compartment, does not take place at the same time. By taking into consideration the maximum of the sum of the volumes of the two compartments 2a 2b during a cycle, and not the sum of the maximum volumes, it is therefore possible to size the system with a buffer tank 1 of smaller volume.

[0068] The membrane 3 is preferably made of a sewn high-temperature fabric. The shape of the membrane 3 is preferably the shape of the interior of one half of the buffer tank 1, said half preferably being defined relative to a vertical plane, i.e. a plane passing, when the buffer tank 1 has a cylindrical envelope, through the axis of the cylinder.

[0069] The device according to the invention comprises a control member 10 of the regeneration unit 9. In order to optimize the operation of the device, the control member 10 comprises means for recovering a forecast 11 of the energy requirements of the consumption unit 7 over time over the entire duration of an operating cycle. The forecast 11 is for example a computer file in the form of a table, in which, for each subdivision of a cycle, a subdivision corresponding for example to one minute, corresponds to an energy requirement of the consumption unit. These energy requirements can be translated into a supply of heat transfer fluid in the consumption fluid circuit 6 at the level of the consumption unit 7, the heat transfer fluid being brought to a certain temperature and supplied at a certain flow rate.

[0070] The control member can also control one or more valves and / or one or more pumps, located at one location or at different locations of the device according to the invention, for the needs of the application case of the invention.

[0071] For example, we can imagine an operating cycle lasting one hour, in which: - During the first five minutes, the consumer unit 7 needs to be supplied with a heat transfer fluid at a temperature of 120°C, at a flow rate of 80 liters per minute,

[0072] - During the last 55 minutes, consumption unit 7 does not require any energy input.

[0073] From the forecast 11, the control unit 10 uses its research means in order to determine an optimal control strategy for the regeneration unit 9. This optimal control strategy must make it possible to meet the needs listed in the forecast 11 throughout the duration of the operating cycle of the device, while minimizing the energy consumed by the regeneration unit 9.

[0074] In order to improve the accuracy of the search for the optimal strategy, the search means of the control member 10 can take into account certain elements which can influence the temperature of the heat transfer fluid at different locations in the device. It may be chosen to take into account one or more of these elements, individually or in combination, depending on their respective importance in the different cases of use.

[0075] The research means can take into account an estimate of the heat losses in the consumption fluid circuit 6 and / or regeneration 8. These estimates can be determined by calculations, or by one or more test cycles.

[0076] The research means may also take into account an estimate of the heat losses in the storage compartment 2b of the buffer tank 1, this estimate taking into account the storage duration of the heat transfer fluid in the storage compartment 2b. This estimate may be determined by calculations, or by one or more test cycles. The research means may also take into account a forecast of the evolution of the outside temperature 1. This forecast may in particular be used to refine the estimates listed above.

[0077] The device according to the invention makes it possible to store a certain quantity of calories or frigories in the storage compartment 2b, for use by the consumption unit 7. The storage compartment 2b being separated from the recovery compartment 2a by the membrane 3, the warm heat transfer fluid coming from the consumption circuit 6 is not mixed with the hot or cold heat transfer fluid coming from the regeneration circuit 9. This makes it possible to optimize the programming of the device. Thus, if, for example, the consumption unit 7 only needs calories or frigories during certain time intervals of the operating cycle of the device, for example 5 minutes every hour, then the rest of the cycle can be used to constitute the necessary energy stock in the storage compartment 2b.The power of the regeneration unit 9 therefore does not need to be sized according to the maximum power of the consumption unit 7. The power of the regeneration unit can be sized according to the average power of the consumption unit 7 over an operating cycle of the device. This advantage is particularly relevant for heating systems. Indeed, in heating systems of the prior art, the heat transfer fluid is often used in the vapor state. Since vapor is difficult to store, in particular because it occupies a large volume, it is necessary to size the power of the regeneration unit higher than the consumption power, the production having to follow the consumption in real time. In the device according to the invention, the heat transfer fluid of the storage compartment 2b is not, or only very little, mixed with the heat transfer fluid of the recovery compartment 2a.This makes it possible to store the heat transfer fluid in the state of superheated water, the temperature of the heat transfer fluid in the storage compartment 2b being almost equal to the temperature of the heat transfer fluid at the outlet of the regeneration unit 9, and this throughout the consumption of the storage volume 2b, without a thermal mixing front.

[0078] The buffer tank 1 preferably comprises two removable shells, and the flexible membrane 3 is fixed in the buffer tank 1 between the two shells.

[0079] The membrane 3 preferably extends parallel to the largest dimension of the buffer tank 1, in order to limit its movements when the volumes of the compartments 2a, 2b vary.

[0080] The pressure of the two compartments 2a, 2b is preferably equal.

[0081] The membrane 3 is set in motion automatically when the volumes of the compartments 2a, 2b vary, i.e. by the inlets and outlets of heat transfer fluid from the compartments 2a, 2b. The movements of the membrane 3 allow the volume occupied by each compartment 2a, 2b to be variable, for example over an interval comprising at least between 10 and 90% of the total volume of the buffer tank 1, i.e. for example variable between 10 and 90%, or 5 and 95%, or 1 and 99%, etc. The movements of the membrane are illustrated in fig. 3, in which three different positions of the membrane 3A, 3B and 3C are shown.

[0082] As illustrated in Fig. 2, the membrane 3 can for example be connected to the inner surface of the buffer tank 1 by hinges 12. The hinges 12 are preferably fixed to the membrane 3 by means of a fixing plate 13. If the surface of the buffer tank 1 has rounded parts, for example in the case of GRC bottoms, fixed hinge supports 14 can be fixed on these rounded parts. The hinge supports 14 then have a first side 15a, of rounded shape, matching the rounded shape of the inner surface of the buffer tank 1, and a second side 15b, straight, materializing the axis of rotation of the hinges 12, and on which the hinges 12 are fixed. The buffer tank 1 is for example a cylindrical tank, closed by two GRC (Large Radius of Square) bottoms. The buffer tank 1 can then comprise 12 hinges 12, distributed as follows:

[0083] - four hinges 12 fixed directly to the walls of the cylinder, two of which are on each side of the membrane 3,

[0084] - eight hinges 12 fixed two by two on four hinge supports 14, two hinge supports 14 being fixed on each GRC bottom.

[0085] As an alternative to the use of hinges 12, the membrane 3 may comprise a cavity 26 all around its perimeter, or over at least a significant part of its perimeter, as illustrated by way of example in FIG. 4. The cavity 26 is preferably formed by a fold of the membrane 3 on itself. A plate 27, for example metallic, may be arranged in the cavity. This plate is configured to rigidly materialize the perimeter of the membrane 2, and to match the internal shape of the buffer tank 1 at its point of contact with the membrane 3. The membrane 3 may then be fixed to the buffer tank 1 by means of the plate 27, for example by means of threaded rods 28 distributed uniformly around the membrane 3, passing through the plate 27, and bolts 29 cooperating with the threaded rods 28.

[0086] When the buffer tank 1 is a cylindrical tank closed by two domed bottoms, the membrane 3 preferably extends from one domed bottom to the other, along a plane generally parallel to the axis of the tank cylinder.

[0087] The seal between the recovery 2a and storage 2b compartments may not be complete. In particular, it is possible to ensure that the compartments 2a, 2b communicate, in order to be able to use a common air purge 16 in the upper part of the buffer tank 1, and a common drain purge 17 in the lower part of the buffer tank 1. This also has the consequence that the pressures are equal in the two compartments 2a, 2b, which facilitates the control of the device according to the invention.

[0088] As illustrated in Fig. 3, the buffer tank 1 may comprise at least one position sensor 18 capable of detecting the position of the membrane 3. This makes it possible to estimate the volumes occupied by each compartment 2a, 2b, and this information can be transmitted to the control member 10. Different types of sensor can be used: infrared sensor, inductive sensor, etc. A single sensor 18 can be arranged in the center of the membrane 3, or several sensors 18 can be distributed over the surface of the membrane 3. In order to detect the position of the membrane 3, the buffer tank 1 may comprise a tube 19, passing through the interior of the buffer tank 1 in a direction parallel to the movement of the membrane 3. The tube 19 passes through the membrane, preferably in its center, and the membrane comprises a target arranged close to the tube 19. The position sensor 18, by detecting the position of the target 19, can thus detect the position of the membrane 3.Figure 3 illustrates this, with the target shown at three different positions 20A, 20B and 20C, corresponding to membrane positions 3A, 3B and 3C.

[0089] In combination with or as an alternative to the position sensor, the device according to the invention may comprise volumetric meters. A first volumetric meter 21 may be arranged to measure the volume of heat transfer fluid passing through the inlet 4a connected to the recovery compartment 2a, and a second volumetric meter 22 may be arranged to measure the volume of heat transfer fluid passing through the outlet 5a connected to the recovery compartment 2a. Alternatively, the first volumetric meter 21 may be arranged to measure the volume of heat transfer fluid passing through the inlet 4b connected to the storage compartment 2b, and the second volumetric meter 22 may be arranged to measure the volume of heat transfer fluid passing through the outlet 5b connected to the storage compartment 2b.The control member 10 can therefore know at any time the volume of heat transfer fluid included in each of the compartments 2a, 2b and adapt the control of the device accordingly.

[0090] In order to refine the estimation of the filling of the compartments of the device according to the invention, the device may comprise a first pressure sensor 23 configured to measure the pressure within the regeneration compartment 2a, and a second pressure sensor 24 configured to measure the pressure within the storage compartment 2b. The control member is then configured to deduce from the data from said pressure sensors information on the filling of the recovery 2a and storage 2b compartments. More precisely, the movement of the membrane 3 does not modify the pressure within the compartments, and the membrane 3 is not perfectly sealed, the pressure differential between the compartments 2a, 2b is generally low, of the order of a few millibars.However, when one of the compartments 2a, 2b is empty or practically empty, and the other is full or practically full, the pressure increases on the full side and decreases on the empty side under the effect of the discharge pressure of the pumps. The control member can then be configured to consider that one of the compartments is full, or full for example at 95% or more, and the other empty, when the pressure differential between the two compartments is greater than a certain threshold. This threshold is for example chosen between 10 millibars and 100 millibars. This makes it possible to reset the data concerning the volume occupied by each compartment 2a, 2b, and thus to avoid a drift in the measurements based solely on the volumetric meters 21, 22 described above, a drift that is difficult to avoid over time depending on the degree of precision of the measurements of the volumetric meters 21, 22.

[0091] The device according to the invention may also comprise a temperature sensor 25 arranged at the inlet 4a of the regeneration compartment 2a. These data allow the control member 10, by combining them with the volume data of the compartments obtained for example in the manner described above, to determine the thermal power which must be brought into the storage compartment, and therefore to control the regeneration unit 9.

[0092] When the position sensor 18 is used in combination with the volumetric counters, it can in particular be used to reset the value of the volume of the compartments when the membrane 3 reaches an extreme position. Indeed, such an extreme position indicates that one of the compartments 2a, 2b occupies a volume close to 0, it can therefore be considered that the volume of the heat transfer fluid in this compartment is zero or it can be assigned a predetermined low value.

[0093] The device according to the invention can be used according to a method comprising the following steps:

[0094] - heating the heat transfer fluid in the regeneration circuit 8 and storing the heat transfer fluid in the storage compartment 2b, until a target quantity of stored heat transfer fluid is reached, corresponding for example to a volume greater than 50% of the buffer tank, this step being carried out over a first period of time, for example greater than 50% of an operating cycle; and

[0095] - sending the heat transfer fluid stored in the storage compartment 2b to the consumption fluid circuit 6, this step being carried out for a second period of time less than said first period of time, for example less than half of the first period of time.

[0096] The present invention is of course not limited to the embodiments described but extends to any modification and variant obvious to a person skilled in the art within the limits of the appended claims. Furthermore, the technical characteristics of the different embodiments and variants mentioned above may be, in whole or in some cases, combined with each other.

Claims

Claims

1. Device for producing and using a heat transfer fluid in a closed circuit according to operating cycles, the device comprising: - a buffer tank (1) comprising two compartments, a recovery compartment (2a) and a storage compartment (2b) separated by a flexible membrane (3), said buffer tank (1) comprising an inlet (4a) and an outlet (5a) connected to the recovery compartment (2a), and an inlet (4b) and an outlet (5b) connected to the storage compartment (2b), - a consumption fluid circuit (6), extending between the outlet (5b) of the storage compartment (2b) and the inlet (4a) of the recovery compartment (2a) of the buffer tank, - at least one consumption unit (7), configured to extract, for a predetermined duration less than the duration of an operating cycle, calories or frigories from the heat transfer fluid at the level of the consumption fluid circuit (6), - a regeneration fluid circuit (8), extending between the outlet (5a) of the recovery compartment (2a) and the inlet (4b) of the storage compartment (2b) of the buffer tank, and - at least one regeneration unit (9) for the heat transfer fluid, configured to provide calories or frigories to the heat transfer fluid at the level of the regeneration fluid circuit (8), characterized in that the device comprises a control member (10) for said at least one regeneration unit (9), said control member (10) comprising: - means for recovering a forecast (11) of the energy requirements of said at least one consumption unit over time over the entire duration of an operating cycle; - search means configured to take into account said forecast (11) and determine an optimal control strategy for said regeneration unit (9) in which the regeneration unit (9) provides the required quantity of energy throughout throughout the duration of the operating cycle; the control member (10) being configured to apply said optimal control strategy to said regeneration unit (9).

2. Device for producing and using a heat transfer fluid according to claim 1, characterized in that the search means are configured to take into consideration an estimate of the heat losses in the consumption fluid circuit (6) when determining the control strategy.

3. Device for producing and using a heat transfer fluid according to one of claims 1 or 2, characterized in that the search means are configured to take into consideration an estimate of the heat losses in the regeneration fluid circuit (8) when determining the control strategy.

4. Device for producing and using a heat transfer fluid according to one of claims 1 to 3, characterized in that the search means are configured to take into consideration an estimate of the heat losses in the storage compartment (2b) of the buffer tank when determining the control strategy, this estimate taking into account the storage duration of the heat transfer fluid in the storage compartment (2b).

5. Device for producing and using a heat transfer fluid according to one of claims 1 to 4, characterized in that the search means are configured to take into consideration a forecast of the evolution of the outside temperature when determining the control strategy.

6. Device for producing and using a heat transfer fluid according to one of claims 1 to 5, in which the buffer tank (1) has a cylindrical shape, closed by two curved bottoms, and the flexible membrane (3) extends from one curved bottom to the other.

7. Device for producing and using a heat transfer fluid according to one of claims 1 to 6, in which the membrane (3) comprises, over all or part of its perimeter, a cavity (26) in which there is a plate (27) capable of matching the internal edges of the buffer tank (1), the plate being fixed to the buffer tank (1) so as to hold the membrane (3) in position in the buffer tank (1).

8. Device for producing and using a heat transfer fluid according to one of claims 1 to 7, characterized in that the membrane (3) is configured so that the volume occupied by each compartment (2a, 2b) is variable over an interval comprising at least between 10 and 90% of the total volume of the buffer tank (1).

9. Device for producing and using a heat transfer fluid according to one of claims 1 to 8, characterized in that the membrane is not completely sealed, so that during operation of the device, except when one of the compartments (2a, 2b) is completely filled, the pressure difference between the recovery (2a) and storage (2b) compartments is less than 20 millibars.

10. Device for producing and using a heat transfer fluid according to one of claims 1 to 9, characterized in that it comprises: - a first volumetric meter (21), configured to measure the volume of heat transfer fluid passing through the inlet (4a) connected to the recovery compartment (2a), and a second volumetric meter (22), configured to measure the volume of heat transfer fluid passing through the outlet (5a) connected to the recovery compartment (2a), or - a first volumetric meter (21), configured to measure the volume of heat transfer fluid passing through the inlet (4b) connected to the storage compartment (2b), and a second volumetric meter (22), configured to measure the volume of heat transfer fluid passing through the outlet (5b) connected to the storage compartment (2b), and in that the control member is configured to deduce from the data from said volumetric meters information on the filling of the recovery (2a) and storage (2b) compartments, and to take this information into account to apply said optimal control strategy to said regeneration unit (9).

11. Device for producing and using a heat transfer fluid according to claim 10, characterized in that it comprises a first pressure sensor (23) configured to measure the pressure within the regeneration compartment (2a) and a second pressure sensor (24) configured to measure the pressure within the storage compartment (2b), the control member being configured to deduce from the data from said pressure sensors information on the filling of the recovery (2a) and storage (2b) compartments.

12. Device for producing and using a heat transfer fluid according to one of claims 1 to 11, characterized in that it comprises at least one temperature sensor (25) configured to measure the temperature of the heat transfer fluid passing through the inlet (4a) connected to the recovery compartment (2a), the control member being configured to use the data from said temperature sensor (25) to control the regeneration unit (9).

13. Method of using a device according to one of claims 1 to 12, comprising an operating cycle comprising the following steps: - heating of the heat transfer fluid in the regeneration circuit (8) and storage of the heat transfer fluid in the storage compartment (2b), until a target quantity of heat transfer fluid to be stored is reached, this step being carried out over a first period of time; and - sending the heat transfer fluid stored in the storage compartment (2b) to the consumption fluid circuit (6), this step being carried out for a second period of time less than said first period of time.

14. A method of using a device according to claim 13, said device being according to claims 11 and 12, further comprising the following steps: - real-time estimation of the volume of the regeneration (2a) and storage (2b) compartments by the control unit (10), taking into account the data from the first volumetric counter (21) and the second volumetric counter (22), - when the data from the first pressure sensor (23) and the second pressure sensor (24) show a pressure differential between the two compartments (2a, 2b) greater than a certain threshold, updating the estimates of the volumes of the compartments, a compartment being considered as occupying a certain proportion of the volume of the buffer tank (1), said proportion being greater than or equal to 95%, - real-time control of the regeneration unit (9) by the control unit (10), using the estimated volume data of the compartments (2a, 2b), and the data from the temperature sensor (25).

15. Method of using a device according to one of claims 1 to 14, characterized in that in the storage compartment (2b), said heat transfer fluid is at least partly in the state of superheated water.

Images