ES2726876T3 - Fluid system and procedure for the control of a fluid system - Google Patents

Abstract

Procedure for the control of a fluid system (10) having a generator fluid circuit (12) and a consumer fluid circuit (14), the generator fluid circuit (12) having at least one heat pump (16; 28), the consumer fluid circuit (14) presenting at least two secondary fluid circuits (62) connected to a supply conduit (58) and a return conduit (60) of the consumer fluid circuit ( 14) and having respectively at least one cooling device (20), as well as a pump (22), the consumer fluid circuit (14) presenting at least one compensation pump (24), characterized in that the pump Heat is a controlled speed heat pump, the at least one compensation pump being controlled so that the mass flow rate in the consumer fluid circuit (14) remains constant, the at least one compensation pump (24) being controlled. way that the transp mass flow Orthed by the at least one compensation pump (24) increases when the mass flow is reduced in a secondary fluid circuit (62) by means of at least one pump (22) and so that the mass flow carried by the at least a compensation pump (24) is reduced when the mass flow increases in a secondary fluid circuit (62) by means of at least one pump (22), the compensation pump (24) being subsequently connected to the supply ducts of the secondary circuits (62) and previously connecting to the return ducts of the secondary fluid circuits (62).

Description

DESCRIPTION

Fluid system and procedure for the control of a fluid system

A fluid system and a procedure for the control of a fluid system are described. Fluid systems are used, for example, to heat and / or cool buildings or facilities.

In these fluid systems, a central heating or cooling source provides a fluid with a certain temperature and guides the fluid through conduits to consumers that provide cooling or heating by heat transfer or heat absorption through of the fluid. As a general rule, a central supply or circulation pump is arranged for this purpose in a circuit of this type. The feed or circulation pump is used to provide the fluid to consumers and to return the fluid to the heating or cooling source. Occasionally, the fluid supply and evacuation ducts can have different lengths, so that, in addition to a pressure drop for consumers very distant from each other, an increase or decrease in fluid temperature can also occur of the feeding duct. This can be compensated by a variation of the speed of the feed or circulation pump or by a variation of the fluid temperature, resulting in the problem that consumers disposed near the heating or cooling source are fed with pressure too high or too high or too low fluid temperature. To avoid this, according to the state of the art, regulating valves or decentralized pumps are provided. Such a system is described, for example, in DE 102013004106 A1. Document DE 102012023848 A1 describes a procedure and a device to simplify the hydraulic adjustment of pipe networks through which the fluid flows. In a pipe network such as this, a characteristic value measurement is performed for a plurality of consumers connected in parallel to the pipe network. Depending on the determined characteristic values, an adjustment of the power of a generator can then be carried out.

EP 2363668 A1 describes a fluid system and a method for controlling a fluid system according to the preamble of claims 1 and 3.

One of the drawbacks of the systems known to the state of the art is its complex structure. In this case it is necessary to provide a plurality of devices (measurement systems, regulating valves, etc.) to make an adjustment. These systems have drawbacks especially with regard to fluctuations by the generator or the consumer. The systems constantly measure the magnitudes of state, changing the heating or cooling power of a heating or cooling device depending on the measurement results. An additional problem of the known systems lies in the generator device (heating or cooling source), especially if a heat pump is intended to be used. In case of heat pumps a frequent connection and disconnection (impulses) represents a problem. However, in systems with different requirements by consumers to a generator (heat pump) impulses are often produced. Conventional heat pumps for cooling or heating systems generally have two states, namely a connected state and a disconnected state. Preferably, the processes of connection and disconnection of heat pumps should be kept reduced. For this reason, in systems with fluctuations in the consumer fluid circuit it is extremely difficult to reduce the impulses of the heat pumps. As a general rule, it is not possible to avoid frequent impulses.

Regulated speed heat pumps are also known from the state of the art. In the case of a controlled speed heat pump, the heat pump power can be adjusted by changing the speed of a compressor. This means that the outlet temperature can be reduced or increased. In a fluid system with several parallel secondary fluid circuits (branches) on the consumer side (consumer fluid circuit), there is a different temperature before each branch. The different branches respectively have a cooling device and a valve or a speed controlled pump by means of which it is possible to regulate the amount of a fluid supplied and, consequently, the cooling power. As the distance between the cooling devices (cooling point) increases, the inertia of the branch increases. In the worst case, this means that the outlet temperature remains so low that the cooling device cannot be cooled optimally or that the controlled speed pump reduces the speed to such an extent that the controlled speed pump is disconnected. automatically.

In addition, in fluid systems of this type, especially in the case of a fluid system with an inverted heat pump on the generator side, there is a risk that such low fluid is transported that the temperature of the fluid rises to the increase the distance with respect to the cold generator, that is, with respect to the heat pump, as a consequence of the heat input from the outside. Therefore, there is the problem that each branch does not have the same temperature. If the temperature of the fluid is not the same at each branch, the mass flow carried through a first branch is considerably lower than the mass flow carried through a last branch.

The following are general descriptions by way of example that represent the increase in mass flow in the last branch (branch 2) compared to the first branch (branch 1) of a fluid system with a temperature rise of 0.5 K , 1 K and 1.5 K during feeding:

Calculation example for 0.5 Kelvin

Branch 1 Branch 2

Q_0 4 4 kW cp 3.5 3.5 kJ / (kg * K) T (supply) -2 -1.5 ° C T (return) 2 2 ° C

Mass flow 0.29 0.33 kg / s Mass flow 1.03 1.18 mA3 / h

Proportion 12.5%

Calculation example for 1 Kelvin

Branch 1 Branch 2

Q_0 4 4 kW cp 3.5 3.5 kJ / (kg * K) T (supply) -2 -1 ° C T (return) 2 2 ° C

Mass flow 0.29 0.38 kg / s Mass flow 1.03 1.37 mA3 / h

25% proportion

Calculation example for 1.5 Kelvin

Branch 1 Branch 2

Q_0 4 4 kW cp 3.5 3.5 kJ / (kg * K) T (supply) -2 -0.5 ° C T (return) 2 2 ° C

Mass flow 0.29 0.46 kg / s Mass flow 1.03 1.65 mA3 / h

Proportion 37.5%

In relation to the fluid system, Q_0 describes the heat flux, T the temperature and cp the specific heat capacity.

In the examples shown above, branch 2 results in an increase in the mass flow rate of approximately 12.5% compared to the mass flow rate in branch 1 with an increase in the temperature during feeding of 0.5 K, an increase in mass flow rate of approximately 25% with an increase in temperature during feeding of 1 K and an increase in mass flow rate of approximately 37.5% with an increase in temperature during feeding of 1.5 K.

In such a fluid system, an increase in temperature occurs during feeding, that is, in a supply conduit of the consumer fluid circuit, even if the fluid is cooled further through the heat pump of investment to reduce the mass flow in the branches. However, as indicated above, such a cooling of the fluid can occur so that the valve or the pump, which control the supply of fluid in the first branch for the cooling device disposed therein, regulates ( practically) completely the contribution of fluid or the pump is disconnected. In addition, in a system of fluid like this there is the problem that the amount of fluid supplied in a last branch can no longer be provided to the extent necessary for more intense cooling if the temperature of the fluid is not reduced through the heat pump of controlled speed. The reason is that the pump or the valve for the cooling device in the last branch already directs a large mass flow to the cooling device anyway, the pump flow volume or the valve opening position being already in its respective maximum. One possibility of compensating it would be to significantly oversize the pump or valve at least in the last branch. However, this makes no sense for economic reasons. Therefore, a regulation of the fluid circuit through a controlled speed heat pump is not suitable for making safe operation of the cooling devices on the branches or in the secondary fluid circuits of a fluid system, to reduce an increase in temperature during feeding or to operate the heat pump efficiently.

Therefore, the task is to propose a fluid system, as well as a procedure for the control of a fluid system that reduces an increase in temperature along a consumer fluid circuit, which provides safe operation of cooling devices and that optimizes the operation of heat controlled speed pumps.

The task is solved by a procedure with the technical characteristics indicated in claim 1 and by a fluid system with the technical characteristics indicated in claim 3. Advantageous improved variants are indicated in the dependent claims.

In a procedure for the control of a fluid system that solves the aforementioned task and which has at least one heat pump of controlled speed and a consumer fluid circuit coupled to the at least one heat pump of controlled speed, presented the consumer fluid circuit at least two secondary fluid circuits, which are connected to a supply conduit and a return conduit of the consumer fluid circuit and which have at least one cooling device, as well as a pump for the regulating the supply of fluid to at least one cooling device, and presenting the consumer fluid circuit at least one compensation pump, the at least one compensation pump is controlled so that the mass flow rate in the fluid circuit of consumer stay constant.

In this case, the at least one controlled speed heat pump is disposed in a generator fluid circuit or forms the generator fluid circuit. In the case of the at least one controlled speed heat pump, a compressor is started depending on the cooling demand required at that time. That is, the power of the controlled speed heat pump also varies. If a reduced cooling power is needed, the controlled speed heat pump is regulated to a reduced power, and if a high cooling power is required, the controlled speed heat pump is regulated to a high power. For this purpose, the speed of a compressor is increased or reduced. The mass flow rate of the fluid, which is cooled by the at least one controlled speed heat pump, is regulated by means of the compensation pump.

In the process, the mass flow rate is kept constant by the at least one compensation pump, which reduces strong fluctuations during the power consumption of the at least one controlled speed heat pump. If, for example, there were an increase in the mass flow rate in a first secondary fluid circuit, this would result in a fluid system without compensation pump that the cooling device would have a lower cooling power in a second circuit of secondary fluid The at least one compensation pump regulates the total mass flow in the consumer fluid circuit so that it remains fundamentally constant. That is, if a larger mass flow is pumped through at least one of the pumps of the secondary fluid circuits, the proportion of mass flow that is pumped through the at least one compensation pump is correspondingly reduced. Similarly, the mass flow rate of the at least one compensation pump increases if the mass flow rate pumped through at least one of the pumps of the secondary fluid circuits is reduced.

In fluid systems without compensation pump, especially the mass flow rate would fluctuate greatly, since the cooling demand of the cooling devices and, therefore, the amount of fluid guided to the cooling devices vary depending on the demand of refrigeration. In case of a high fluid demand, a correspondingly large mass flow rate would be provided to the cooling devices and the temperature of the fluid in the return or in the return conduit would increase accordingly. Therefore, the power of the controlled speed heat pump would increase, resulting in a reduction of the mass flow rate in the secondary fluid circuits for the cooling devices, since less fluid is required for cooling due to the reduction of the fluid temperature. As a consequence of a reduction in the mass flow rate, for example, the speed of the pumps in the secondary fluid circuits can be reduced to such an extent that the supply of fluid in the secondary fluid circuits is interrupted.

The procedure described here and also the fluid system described below reduce these fluctuations of the mass flow rate, the at least one compensation pump operating in a variable way, in order to keep the total mass flow rate fundamentally constant.

Especially, the at least one compensation pump is regulated according to the at least one heat pump and to the pumps in the secondary fluid circuits, so that in sum the mass flow rate in the consumer fluid circuit is constant.

Another advantage is that it is possible to store the "cold" through the volume in the pipes of the consumer fluid circuit.

A generator fluid circuit and the consumer fluid circuit may respectively have at least one supply duct and a return duct. The parallel secondary fluid circuits can be connected to the supply and return ducts of the generator fluid circuit and the consumer fluid circuit, the input and return ducts of the secondary fluid circuits being connected correspondingly to the input and return ducts of the respective main circuits. To do this, the fluid system has pipe systems in which the fluid is guided. As a fluid for the fluid system, water with a freezing additive (coolant) is used, such as saline water. In this case, saline water can be a mixture of water and glycol.

In the case of a fluid system with only one cooling device and relatively short duct lengths, especially in the consumer fluid circuit, a compensation pump is sufficient for the adjustment of the mass flow rate ratio and for the contribution of the fluid to the cooling device. Various compensation pumps arranged in different positions of the consumer fluid circuit can also be provided. The at least one compensation pump is arranged as a central pump according to the invention between the supply duct and the return duct of the consumer fluid circuit. If the fluid system has several cooling devices, these are arranged in the consumer fluid circuit through the parallel secondary fluid circuits mentioned above. The secondary fluid circuits respectively have at least one cooling device and a pump for the contribution of the fluid to the cooling device. The pump regulates the contribution of the fluid independently of the contribution of the fluid in the supply conduit of the main consumer fluid circuit. The pumps are arranged as decentralized pumps in the consumer fluid circuit. Next, the at least one compensation pump in the main consumer fluid circuit is regulated depending on the cooling needs of the cooling devices, the total mass flow being maintained in the constant consumer fluid circuit. For this, the at least one compensation pump and the cooling device pumps may be speed controlled pumps. If the speed of the pumps for the cooling devices is increased, in order to make a greater cooling power available through the cooling devices, the speed of the at least one compensation pump is correspondingly reduced, being controlled the speed so that, on average, the temperature difference between the feed (supply duct) and the return (return duct) of the main consumer fluid circuit is 4 Kelvin. In addition, the speed of the at least one compensation pump can be regulated so that the heat pump is switched off if the temperature difference drops below 2.5 Kelvin (+/- 0.5 Kelvin).

In case of larger fluid systems, at least two controlled speed heat pumps connected in parallel can be provided. For example, to cool the fluid, two controlled speed heat pumps or only one controlled speed heat pump can be operated simultaneously. One of the two heat pumps of controlled speed can be permanently in operation for the basic feeding, that is, for the reduction of the temperature of the fluid, being able to carry out the reduction of the temperature of the fluid through the heat pumps of controlled speed in a certain range also only with one of the heat controlled speed pumps. For example, a reduction in fluid temperature over a given temperature range is possible (depending on the power of controlled-speed heat pumps).

However, if a significantly greater reduction in fluid temperature is required, at least a second heat pump of controlled speed is connected. If the cooling demand of the cooling devices remains fundamentally constant or is not subject to large fluctuations, the operation of a controlled speed heat pump can be maintained. If there is a greater demand for cooling, the pumps of the cooling devices are regulated accordingly, which means that a greater mass flow flows through the secondary fluid circuits and the compensation pump compensates for the fluctuation for the maintenance of the Mass flow in the consumer fluid circuit. In case of a higher cooling demand, an increase in the temperature of the fluid in the return duct of the consumer fluid circuit may occur. An increase in the fluid temperature can also occur in the supply conduit of the consumer fluid circuit. In this case there is an increase in the temperature difference between the supply duct and the return duct in the consumer fluid circuit. Next, the speed of a first heat pump of controlled speed is increased and / or a second heat pump of controlled speed is put into operation. Then, the second controlled speed heat pump further cools the fluid until the originally predicted and adjusted temperature of the fluid in the supply conduit of the consumer fluid circuit is reached again. In addition, the temperature of the fluid in the return duct of the consumer fluid circuit and in the supply duct of the generator fluid circuit is reduced. If there is a high demand for cooling, it may be necessary to operate the second heat pump with controlled speed for a longer period of time. A higher cooling demand can be detected by the speed of the cooling device pumps, by the control signals of the pumps and / or through a pump data interface. Depending on this information, the speed variation of the controlled speed heat pumps and the connection and disconnection of the first and second controlled heat pumps can be controlled. First, the speed control of the first and second heat pump of controlled speed is carried out, as well as the connection and disconnection of the heat pumps of controlled speed depending on the temperature of the fluid.

Alternatively, in other fluid systems a third speed controlled heat pump may also be operated alternatively or additionally to the second controlled speed heat pump, in order to achieve additional cooling, or the second and third heat pump. Heat of controlled speed can be activated alternately if there is a greater demand for cooling. In a fluid system, more than three heat pumps of controlled speed can also be provided.

The control of the contribution of the fluid to at least one cooling device is carried out by means of the pump assigned to this cooling device. In an ideal case, the contribution of the fluid to the cooling device is constant. The regulation of the fluid in the consumer fluid circuit is carried out by means of the compensation pump that can be configured as a so-called overflow pump.

As described above, the fluid system may have at least two heat pumps of controlled speed, the at least two heat pumps being controlled according to the temperature of the fluid in the generator fluid circuit and / or in the circuit of consumer fluid

In the process, especially the controlled speed heat pump and a controlled speed compensation pump, as well as the controlled speed pumps in the secondary fluid circuits, can keep the fluid temperature fundamentally constant and are not subject to large fluctuations. of temperature as occurs, for example, in fluid systems with conventional heat pumps due to their frequent connection and disconnection.

The fluid system can be operated primarily in a first mode of operation, in which a fundamentally constant mass flow rate is adjusted in the fluid system or in the consumer fluid circuit, maintaining a temperature difference between the feed and the return, and in a second mode of operation, in which the temperature of the fluid is reduced below a theoretical temperature to store the "cold", the temperature difference between the feed and the return below a threshold value can fall .

In a fluid system that solves the aforementioned task and which comprises a generator fluid circuit and a consumer fluid circuit,

- the generator fluid circuit has at least one controlled speed heat pump,

- the consumer fluid circuit has at least two secondary fluid circuits connected respectively to a supply duct and a return duct of the consumer fluid circuit,

- the secondary fluid circuits respectively have at least one cooling device and a pump,

- the consumer fluid circuit has at least one compensation pump, and

- the at least one compensation pump can be controlled so that the mass flow rate in the consumer fluid circuit remains constant.

For this purpose, the at least one compensation pump is disposed between the supply duct and the return duct of the consumer fluid circuit. The control or regulation of the compensation pump is carried out depending on the cooling demand of the at least one cooling device, that is, of the mass flow rate contributed to the cooling device through the cooling device pump, and depending on the power of the at least one controlled speed heat pump.

In order to keep the mass flow rate constant in the consumer fluid circuit, the compensation pump is regulated so that it compensates for these fluctuations, due to the different power requirements of the cooling devices (cooling demand) and, therefore, to the different flow rates of the pumps, to achieve a theoretical fluid flow.

As already indicated at the beginning in relation to the process, the consumer fluid circuit has a plurality of cooling devices and respectively a pump assigned to the cooling devices, the cooling devices and the pumps assigned in fluid circuits being arranged parallel sideways and connecting them to the supply duct and the return duct of the consumer fluid circuit. According to the invention, the consumer fluid circuit has at least two parallel secondary fluid circuits with respectively a pump and a cooling device, the supply conduits of the secondary fluid circuits of the consumer fluid circuit are connected to the supply conduit of the consumer fluid circuit and connecting the return conduits of the secondary fluid circuits to the return conduit of the consumer fluid circuit. Additionally or alternatively, a generator fluid circuit may have at least two parallel secondary fluid circuits with a heat pump of controlled speed, connecting the supply conduits of the secondary fluid circuits of the generator fluid circuit to a supply conduit of the generator fluid circuit and connecting the return conduits of the secondary fluid circuits to a return conduit of the generator fluid circuit.

The fluid system contains a refrigerant housed in the conduits of the consumer fluid system and the generator fluid system. Water can be used as a refrigerant carrier with a freezing agent, especially a so-called saline water comprising a mixture of water and glycol.

The at least one compensation pump, the at least one input pump and / or the at least one pump may be speed controlled pumps. The pumps of controlled speed or regulated speed can be easily modified in terms of their flow and controlled centrally. The at least one compensation pump can be configured as a so-called overflow pump.

At least in the return conduit of the consumer fluid circuit, in the supply conduit of the consumer fluid circuit, in a return conduit of the generator fluid circuit and / or in a supply conduit of the fluid flow circuit of generator can be provided at least one temperature measuring device. The temperature measuring devices serve to measure the temperature of the fluid at various points in the fluid system. Depending on the temperature of the measured fluid, for example, the operation of heat controlled speed pumps can be controlled. For this, reference is made to the temperature dependent procedures described at the beginning.

The cooling devices may be heat exchangers, for example, plate or tube heat exchangers with a blower or a fan.

In the fluid system, the feed temperatures of each branch (secondary fluid circuit) can be adjusted by means of the at least one controlled speed compensation pump (overflow pump).

The fundamental components of the fluid system are the at least one controlled speed heat pump (power adaptation), the at least one compensation pump (overflow pump), the decentralized pump system in the secondary fluid circuits and the Temperature distribution between feed and return to 4 Kelvin if no cold storage is carried out.

In addition, in the case of a connection to two heat pumps of controlled speed, it is possible to also adjust the temperatures before the branches (secondary fluid circuits). If greater cooling power is required, reducing the AT temperature difference to less than 4 Kelvin through the heat exchanger (WT) of the controlled speed heat pump, a three-way valve is opened in the supply duct of the generator fluid circuit (return) of the two controlled speed heat pumps. This valve opens until the desired distribution is adjusted through the WT of the first controlled speed heat pump. In addition, the second controlled speed heat pump operates in a regulated manner. The power of the second heat pump of controlled speed is raised until the theoretical distribution of 4 Kelvin in the second heat pump of controlled speed is also adjusted. If a lower cooling power is needed again, the speed of the second heat pump of controlled speed is reduced until the theoretical distribution is reached. As soon as additional cooling power is no longer required, the second controlled speed heat pump is disconnected and the 3-way valve closes the path to the second controlled speed heat pump.

The fundamental components of this fluid system with two controlled speed heat pumps are two controlled speed heat pumps, which can be adapted in terms of their power, a 3-way valve, the at least one compensation pump (pump overflow), the decentralized pump system in the secondary fluid circuits and the temperature distribution between the feed and the return to 4 Kelvin if no cold storage is carried out.

The compensation pump (overflow pump) also allows additional storage of the "cold" in the fluid system. As in a fluid system with a "cold" shock absorber, the assembly allows the "cold" to be stored. On the one hand, increasing the speed of the compensation pump (overflow pump). As a consequence, more cold fluid flows into the return (return) conduit of the consumer fluid circuit, whereby the temperature of the fluid in the return conduit is reduced. This means that, in the first step, the cooling power is destroyed by mixing the cold fluid with the hottest fluid in the return conduits of the different secondary circuits (branches), but this can be advantageous if, for example, Energy costs for the operation of heat-controlled heat pumps are likely to increase. For example, a photovoltaic system provides the current for the operation of the fluid system. If the photovoltaic system can generate less current or cannot generate any current, the current for operation must be obtained, for example, through a public electricity grid, which is much more expensive. In addition, electricity prices fluctuate for a certain period of time (day / week / month), the "cold" being stored when electricity costs are low and the "cold" stored in the fluid being transferred when electricity costs They are higher. This means, for example, that when the photovoltaic power decreases, the energy consumption of the controlled speed heat pump is reduced due to the reduction of the fluid temperature during return. This also applies to load reduction. If a power peak (current peak) is expected to result from the connection of another load, this procedure allows reducing the electrical consumption of the controlled speed heat pump. Also There is the possibility of storing the "cold" in the set due to the excess of photovoltaic current or a favorable "flexible current" (excessive supply of current due to too high power in a network). For this, the theoretical temperature is reduced. In addition, the speed of the compensation pump (overflow pump) can also be increased (depending on the needs).

To store the "cold", either the speed is increased in case of a controlled speed heat pump or a second controlled speed heat pump is connected, whereby the temperature of the fluid can be reduced. In this case, the temperature of the fluid in the supply conduit of the consumer fluid circuit is reduced. For this reason, the pumps of the cooling devices are regulated accordingly, so that less fluid is supplied to the cooling devices. However, the cooling power of the cooling devices remains fundamentally the same. As a consequence, the cooling temperature in the return duct of the consumer fluid circuit is also reduced. After the decrease in the temperature of the fluid, only a controlled speed heat pump can be operated that keeps the temperature of the fluid at the reduced temperature level. If a greater cooling power of the cooling devices is required, it can be obtained from the fluid. In this case, the temperature of the fluid in the return duct of the consumer fluid circuit increases, but remains below or is fundamentally equal to the temperature level before the fluid temperature drops. If the temperature of the fluid in the return line of the consumer fluid circuit exceeds a determinable threshold value, the speed of the controlled speed heat pumps increases and / or the second controlled speed heat pump is connected.

Therefore, especially in the case of long ducts, the fluid system can make available a relatively large "cold" shock absorber. For example, it is possible to store the "cold" at night if the energy costs for the operation of the heat pumps are low. The at least one controlled speed heat pump may be an inversion heat pump. In an inverted heat pump, the heat pump compressor is regulated continuously, thereby influencing the power consumption of the compressor.

Here we always talk about mass flows and proportions of mass flow. However, one can also talk about volumetric flows and volumetric flow rates. There is no variation or at least only an insignificant variation in fluid density, so that in relation to the fluid system and the procedure for the control of the fluid system it is generally considered that the mass flow rate is equivalent to the flow rate. volumetric. In addition, the advantages mentioned for the process are also valid for the fluid system and vice versa.

Other advantages, characteristics, as well as configuration possibilities result from the following description of the figures of embodiments to be understood in a non-restrictive manner.

In the drawings it is shown in the:

Figure 1 a schematic representation of a fluid system;

Figure 2 a schematic representation of another fluid system; Y

Figure 3 a schematic representation of the mass flow rates in the consumer fluid circuit.

The pieces provided in the figures of the same references correspond fundamentally to each other, provided that the contrary is not indicated. In addition, a description of the elements and components that are not essential for the understanding of the technical theory disclosed here is dispensed with.

Figure 1 shows a fluid system 10 having a generator fluid circuit 12 and a consumer fluid circuit 14. The generator fluid circuit 12 has a controlled speed heat pump 16. The speed heat pump Controlled 16 is coupled to the consumer fluid circuit 14 through a heat exchanger 30. The heat exchanger 30 comprises an evaporator. The heat of the fluid in the consumer fluid circuit 14 is absorbed through the heat exchanger 30 by means of a working fluid (coolant) circulating in the heat pump 16. Here, the fluid in the fluid circuit of consumer 14 is cooled and the working fluid is heated. In a compressor 40, the working fluid is compressed and in a second heat exchanger 32, which has a condenser, the working fluid transfers heat to a fluid circulating in a second fluid circuit. An expansion valve 42 is arranged between the condenser and the compressor. The working fluid is expanded by means of the expansion valve 42, reducing the pressure of the working fluid and cooling the working fluid and partially evaporating. In the heat exchanger 30 (evaporator), the working fluid absorbs by evaporation the heat of the consumer fluid circuit 14 provided through a return duct 60. Next, the compressor 40 again aspirates the evaporated working fluid And compress it.

In the second fluid circuit, the heated fluid is supplied through a feed pump 18 to an unspecified hydraulic separator that is coupled to a second consumer fluid circuit. In the second consumer fluid circuit, heating devices are provided to heat a space or an installation. The second fluid circuit comprises other components such as feed pumps, valves, heat exchangers and heating devices not shown in Figure 1 and not described in more detail.

The consumer fluid circuit 14 is coupled through the heat exchanger 30 to the heat pump 16 which serves to cool the fluid contained in the consumer fluid circuit 14. The fluid cooled by means of the heat pump 16 a through the heat exchanger 30, it is introduced into a supply conduit 58 of the consumer fluid circuit 14 and circulates through the heat exchanger 30 through the contribution conduit 58 and the return conduit 60.

The ducts of the fluid system 10 have cross sections that are determined depending on the cooling power to be achieved, the length of the ducts and the size of the fluid system 10. The duct cross sections can also differ from each other in The different ducts. In addition, duct cross sections may also vary along their length.

The consumer fluid circuit 14 has several parallel secondary fluid circuits 62. The supply conduits of the secondary fluid circuits 62 are connected to the input conduit 58 of the main fluid circuit of the consumer fluid circuit 14. The supply conduits The return of the secondary fluid circuits 62 are connected to the return duct 60 of the main fluid circuit of the consumer fluid circuit 14. The pumps 22 and the cooling devices 20, as well as the valves, are arranged in the fluid circuits Secondary 62. The pumps 22 regulate the contribution of the fluid cooled by the heat pump 16 to the cooling devices 20. The pumps 22 are arranged in the secondary fluid circuits 62 so that these are previously connected to the cooling devices 20 The fluid flowing through the cooling devices 20 is redirected through the return ducts of the secondary fluid circuits 62, the return conduits converging in the return conduit 60 of the main fluid circuit. The pumps 22 allow a contribution of the cooled fluid to the cooling devices 20 as a function of demand. The secondary fluid circuits 62 can be separated from the main fluid circuit through the valves.

Between the supply conduit 58 and the return conduit 60, a compensation pump 24 is arranged. The compensation pump 24 is arranged in the main fluid circuit of the consumer fluid circuit 14 so that it is subsequently connected to the supply conduits of the secondary fluid circuits 62 and so that it is previously connected to the return conduits of the secondary fluid circuits 62. The compensation pump 24 is used to adjust a mass flow rate or a constant volumetric flow in the consumer fluid circuit 14. The compensation pump 24 is configured as a so-called overflow pump. In the exemplary embodiment of Figure 1, the circulation of the fluid is also carried out by means of the compensation pump 24. In this case, the compensation pump 24 also serves as a feed pump. The compensation pump 24 is a controlled speed pump and, therefore, can regulate the mass flow rate in the consumer fluid circuit 14. The compensation pump 24 is controlled so that the total mass flow rate in the fluid circuit of consumer 14 remain fundamentally constant. That is, the flow through the compensation pump 24 is reduced if the flow in the secondary fluid circuits 62 is increased by means of the pumps 22, and the flow through the compensation pump 24 increases if the flow in The secondary fluid circuits 62 are reduced by means of the pumps 22. Here, the total flow or the total mass flow remains fundamentally constant. In this way it is further avoided that, in the case of a high cooling demand, the fluid in the supply line 58 is reduced so that, for example, the pump 22 in the first secondary fluid circuit 62 is disconnected, since The fluid temperature is too low.

The fluid system 10 also has several temperature measuring devices and control and regulation units. The temperature measuring devices are at least in the return duct 60 and in the supply duct 58. Additional temperature measuring devices and measuring devices can also be provided at other points of the fluid system 10.

The fluid system 10 contains as a fluid a refrigerant (antifreeze water), especially saline water. Saline water is a mixture of water and glycol. The heat pump 16 is configured and conceived to provide a determined cooling of the fluid. By means of the heat pump 16, a specific heating of a fluid in the second fluid circuit is also obtained. The temperature distribution, that is, the temperature difference between the temperature of the fluid in the return duct 60 and in the supply duct 58 is 4 Kelvin in normal operation. To achieve this, the speed of the compressor 40 is controlled accordingly.

In normal operation of the fluid system 10, all valves that can be configured, for example, as magnetic valves, are open.

In a first exemplary drive of the fluid system 10, a cooling of the fluid in the consumer fluid circuit 14 is carried out, the fluid being cooled in 4 Kelvin by the heat exchanger 30. The temperature of the fluid in the input duct 58 and in the return duct 60 is measured by means of a temperature measuring device.

The cooled fluid is supplied to the secondary fluid circuits 62 through the supply duct 58. Depending on the cooling demand, the pumps 22 regulate the contribution of the fluid to the cooling devices 20. The fluid absorbs heat in the cooling devices 20. The heated fluid is then supplied to the return duct 60 through the return ducts of the secondary fluid circuits 62. A temperature measuring device is provided in the return duct 60 that measures the temperature of the fluid in the return duct 60. The temperature of the fluid in the return duct 60 is higher than the temperature of the fluid in the supply duct 58. Depending on the determined temperature difference, the pump control is carried out of heat 16 and, consequently, the cooling of the fluid. For example, the heat pump 16 can carry out a full cooling of the fluid up to 10 Kelvin. If a temperature difference of the fluid temperature greater than 4 Kelvin is determined between the return line 60 and the supply line 58, the speed of the compressor 40 is increased, resulting in a more intense cooling of the fluid. The heat pump 16 returns the fluid at the temperature that has been measured in the supply conduit 58 and that has been preset. Temperature levels can be preset and modified through a centralized control system.

Depending on the contribution of the fluid to the cooling devices 20 through the pumps 22, the compensation pump 24 regulates the mass flow rate or the total volumetric flow in the consumer fluid circuit 14. The compensation pump 24 is regulated by so that the mass flow rate in the consumer fluid circuit 14 is constant. If a higher mass flow rate is obtained through the pumps 22, the mass flow rate transported through the compensation pump 24 is reduced. Similarly, the mass flow that is transported through the compensation pump 24 increases if the mass flow is reduced by means of the pumps 22. The pumps 22 and the compensation pump 24 are configured as controlled speed pumps and receive signals from control of a control not represented. These control signals and / or signals through the data interfaces of the pumps 22 and the compensation pump 24 are used for the determination and adjustment of the mass flow rate. The mass flows transported by the respective pumps 22 are added. Depending on a total adjustable mass flow rate in the consumer fluid circuit 14, the speed of the compensation pump 24 is then determined, so that the total mass flow rate remains constant.

By adjusting the total mass flow, slight variations in the theoretical total mass flow may occur in the consumer fluid circuit 14. For this reason, the total mass flow is not always constant, although these variations conditioned by the regulation are very small and, Therefore, insignificant.

To optimize the operation of the fluid system 10 and, for example, to reduce the energy costs of operating the heat pump 16, the heat pump 16 can be intentionally controlled so that the temperature of the fluid in the supply conduit drops by below a required theoretical temperature. This happens regardless of whether there really is an increase in the demand for cooling. After increasing the speed of the heat pump 16, the fluid in the consumer fluid circuit 14 cools. Thus, the cooling devices 20 also need less fluid and the speed of the pumps 22 is adjusted accordingly, so that the mass flow rate through the secondary fluid circuits 62 decreases. Accordingly, the mass flow rate of the compensation pump 24 increases and the temperature of the fluid in the return line 60 is below a normal temperature, at which a difference of 4 Kelvin predominates between the return line 60 and the supply duct 58. This is considered tolerable for "cold" storage operation.

The "cold" storage can be carried out in the fluid system 10 if the energy costs for the operation of the heat pump 16 are reduced. For example, this is the case at night or when cheap electricity is available from generation facilities for renewable energy (wind power, solar electricity, etc.). If the energy costs increase, the operation of the heat pump 16 can be reduced, so that the heat pump 16 only requests a part of its power and operates in a lower partial load mode. A disconnection of the heat pump 16 can also occur if the fluid has cooled accordingly. In this case, the necessary heat is obtained from the fluid whose temperature is below a certain temperature level for normal operation. The heat pump 16 can also maintain the cooling of the fluid at a certain temperature level in the partial load operation, obtaining a greater cooling power of the "cold" stored in the fluid. If the temperature difference between the return line 60 and the supply line 58 exceeds a certain value, for example 4 Kelvin, the power of the heat pump 16 is increased by increasing the speed of the compressor 40.

Figure 2 shows a schematic representation of another fluid system 10. The fluid system 10 shown in Figure 2 differs from the fluid system 10 shown in Figure 1 primarily in that two controlled speed heat pumps 16 and 28. A 3-way valve 50 is provided in the return line 60. The 3-way valve 50 can be controlled through a central control system and, depending on the control specifications, regulates the fluid supply to the first controlled speed heat pump 16 and the second controlled speed heat pump 28. To achieve a further reduction of the fluid temperature, the fluid can be guided through the 3-way valve 50 to both the heat exchanger 30 of the first heat pump 16, as well as the heat exchanger 30 of the second heat pump 28. This is especially convenient if the "cold" should be stored in the heat system. fluid 10, in particular in the consumer fluid circuit 14.

In the case of a fluid system 10 for buildings or installations it is possible to carry out a reduction in the temperature of the fluid, for example, during the night, since the energy costs of the electricity required by heat pumps 16 and 28 are less than during the day. The pumps 22 transport less fluid to the devices 20, maintaining the cooling power of the devices 20. Once the fluid temperature has been reduced, the heat pump can be disconnected. During the day the cooling of the fluid takes place during a period of time determined only by a heat pump 16, being able to compensate for the higher cooling powers, due, for example, to the higher outside temperatures, with the "cold" stored in the supply duct 58 and in the return duct 60. The temperature of the fluid for activating at least one additional heat pump 28 and for increasing the power of the heat pump 16 is only reached later, since the temperature of the fluid in the supply duct 58 and in the duct Return 60 is lower than the normal fluid temperature. In this way it is possible to reduce the energy costs of electricity for the operation of heat pumps 16 and 28 during the day.

Advantageously, the compensation pump 24 is controlled so that the mass flow of the fluid in the consumer fluid circuit 14 is kept constant. Especially, the compensation pump 24 operates so as to compensate for these fluctuations in the secondary fluid circuits 62 with the pumps 22 and the cooling devices 20.

Figure 3 shows via line 74 a theoretical mass flow rate that must be kept constant in the consumer fluid circuit 14. Since the mass flow rates or volumetric flows of the cooling devices 20 vary and that the amount of fluid in the circuits of secondary fluid 62 fluctuates due to the pumps 22, the flow of the compensation pump 24 adapts to the mass flow of the pumps 22. The development 76 shows the mass flow that is transported by means of the pumps 22. The gray surface 70 located behind represents the proportion of mass flow of the pumps 22 in the total mass flow. The difference between development 76 and line 74 represents the proportion of the compensation pump 24 in the total mass flow in the consumer fluid circuit 14. The proportion of the compensation pump 24 varies analogously to the proportion of the pumps 22 , keeping the sum of the fundamental flow rates fundamentally constant thanks to the adjustment of the mass flow rate transported by the compensation pump 24 to the mass flow rate transported by the pumps 22. In the representation of figure 3, the proportion of the mass flow rate of the compensation pump 24 is between lines 74 and 72. For example, the compensation pump 24 for the fluid system 10 is designed and selected according to a calculation for the operating range of the compensation pump 24 based on the previously determined proportion of the mass flow transported.

In the fluid system 10 described above, the "cold" can be easily stored. In addition, the mass flow rate in the consumer fluid circuit 14 remains constant, for which the compensation pump 24 compensates for fluctuations with the cooling devices 20.

Reference List

10 Fluid System

12 Generator fluid circuit

14 Consumer fluid circuit

16 Heat pump

18 Feed pump

20 Cooling device

22 Bomb

24 Compensation pump

28 heat pump

30 Heat exchanger

32 Heat exchanger

40 Compressor

42 Expansion Valve

50 3-way valve

58 Contribution channel

60 Return duct

62 Secondary fluid circuit

70 Surface

72 Line

74 Line

76 Development

Claims (8)

1. Procedure for the control of a fluid system (10) having a generator fluid circuit (12) and a consumer fluid circuit (14), the generator fluid circuit (12) having at least one pump of heat (16; 28), the consumer fluid circuit (14) having at least two secondary fluid circuits (62) connected to a supply duct (58) and a return duct (60) of the fluid circuit of consumer (14) and having respectively at least one cooling device (20), as well as a pump (22), the consumer fluid circuit (14) having at least one compensation pump (24), characterized in that the Heat pump is a controlled speed heat pump, the at least one compensation pump being controlled so that the mass flow rate in the consumer fluid circuit (14) remains constant, the at least one compensation pump (24) being controlled. ) so that the mass flow rate Supported by the at least one compensation pump (24) increases when the mass flow rate is reduced in a secondary fluid circuit (62) by means of at least one pump (22) and so that the mass flow rate carried by the at least a compensation pump (24) is reduced when the mass flow increases in a secondary fluid circuit (62) by means of at least one pump (22), the compensation pump (24) being subsequently connected to the supply ducts of the secondary circuits (62) and previously connecting to the return ducts of the secondary fluid circuits (62). 2. Method according to claim 1, the at least one controlled speed heat pump (16; 28) being controlled according to the temperature of the fluid in the return duct (60) and / or in the supply duct (58) of the consumer fluid circuit (14). 3. Fluid system having a generator fluid circuit (12) and a consumer fluid circuit (14), - the generator fluid circuit (12) having at least one heat pump (16; 28), - the consumer fluid circuit (14) having at least two secondary fluid circuits (62) connected respectively to a supply duct (58) and a return duct (60) of the consumer fluid circuit (14), - presenting the secondary fluid circuits (62) respectively at least one cooling device (20) and a pump (22), - the consumer fluid circuit (14) presenting at least one compensation pump (24), characterized in that - the heat pump is a controlled speed heat pump, - the at least one compensation pump (24) can be controlled so that the mass flow rate in the consumer fluid circuit (14) remains constant, - the at least one compensation pump (24) being controlled so that the mass flow carried by the at least one compensation pump (24) increases when the mass flow is reduced in a secondary fluid circuit (62) by means of the less a pump (22) and so that the mass flow carried by the at least one compensation pump (24) is reduced when the mass flow increases in a secondary fluid circuit (62) by means of at least one pump (22 ), the compensation pump (24) being subsequently connected to the supply ducts of the secondary circuits (62) and previously connected to the return ducts of the secondary fluid circuits (62). 4. Fluid system according to claim 3, a coolant being housed in the fluid system (10). 5. Fluid system according to claim 3 or 4, the generator fluid circuit (12) having at least two heat pumps of controlled speed (16; 28) and joining the return line (60) of the fluid circuit of consumer (14), through a valve assembly, at at least two controlled speed heat pumps (16; 28). 6. Fluid system according to one of claims 3 to 5, the at least one being a compensation pump (24) and / or the at least one pump (22) controlled speed pumps. 7. Fluid system according to one of claims 3 to 6, at least provided in the - return duct (60) of the consumer fluid circuit (14), in the - supply duct (58) of the consumer fluid circuit (14) and / or in the - generator fluid circuit (12) At least one temperature measuring device. 8. Fluid system according to one of claims 3 to 7, the at least one being a controlled speed heat pump (16; 28) being an inverter heat pump.