Abstract:
The invention relates to a cooling and/or heating device ( 10, 60 ) of one or more units ( 8   a  to  8   c ) that are to be heated or cooled. The device comprises: a conduit network containing flow and return conduits ( 14, 16; 68, 70 ), several circuits ( 12   a  to  12   c   ; 32  to  38, 74  to  78 ) being connected to the flow and return conduits ( 14, 16; 68, 70 ); several valves ( 28, 88, 96 ) that are configured to adjust the passages of the valves in order to regulate or control the volumetric flow through the circuits ( 12   a  to  12   c   ; 32  to  38; 74  to  78 ), a fluid that acts as a heat transfer medium or coolant in the conduit network; and at least one consumer in each circuit, such as a radiator or heat sink ( 22 ), heat exchanger or similar. The invention is characterized in that the valves ( 28, 88, 96 ) are connected to a control unit ( 40 ) for regulating the passages of the valves ( 28, 88, 96 ) and that the valves ( 28, 88, 96 ) can be adjusted by the control unit ( 40 ) in such a way that the individual circuits ( 12   a  to  12   c   ; 32  to  38; 74  to  78 ) are hydraulically balanced.

Description:
BACKGROUND  
       [0001]     The invention pertains to a cooling and/or heating device of the type described in the preamble of claim  1 .  
         [0002]     Such a cooling and/or heating device is known, for example, from EP 1 207 355 A2 and features a conduit network for at least one building with a main supply line. The main supply line is provided with a main flow conduit and a main return conduit. A fluid serves as the heat transfer medium or coolant in the conduit network. A heating circuit, a domestic water circuit and a ventilating circuit are connected to a distribution unit and feature heating/cooling sections with at least one valve each and at least one consuming device, e.g., a radiator/heat sink, a heat exchanger or the like. The distribution unit with the circuits connected thereto forms a supply unit. A valve arranged upstream or downstream of the supply unit is controlled as a function of the differential pressure between the supply conduit and return conduit. This differential pressure valve stabilizes the differential pressure between the supply conduit and return conduit of the supply unit such that the pressure in the supply unit can be maintained nearly constant and the supply units are uniformly supplied.  
         [0003]     The individual circuits in the supply unit form so-called hydraulic circuits that can be either identical or configured differently.  
         [0004]     EP 1 116 921 A2 also discloses a room air-conditioning system for buildings that comprises a device for heating and/or cooling a heat transfer medium and/or a coolant, several heat exchangers that release the heat of the medium into the surroundings and/or absorb the heat of the surroundings into the coolant, pipelines connecting the heat exchangers and the heating/cooling device to one another in order to transport the medium, and valves that are assigned to the heat exchangers and serve for adjusting the volumetric flow of the medium through the heat exchangers. A device for adjusting the medium pressure is also provided in order to vary the pressure of the medium. In addition, pressure sensors are assigned to the valves and actuators are provided for adjusting the valves. The device for adjusting the medium pressure makes it possible to obtain a central setpoint setting, for example, in order to centrally control a nighttime setback. Signals that switch the valves between nighttime setback and daytime settings are transmitted to pressure sensors in the form of predetermined pressure fluctuations. For this purpose, each pressure sensor features a sensor element that is moved as a function of the pressure of the medium, wherein said sensor element is mechanically, hydraulically, pneumatically or electrically coupled to the actuator of the valve and acts thereupon to adjust the valves. The valves are in this case provided in the form of thermostatic valves. This is intended to make it possible to switch the valve, for example, between nighttime setback and daytime settings independently of signal lines by means of the medium, such that the temperature setpoint is centrally adjusted.  
         [0005]     Furthermore, DE 100 57 416 A1 discloses a central heating system for rooms to be heated in one or more buildings, wherein this system comprises a conduit network featuring flow and return conduits. Several heating sections are connected by means of supply and return conduits and are respectively provided with a valve for regulating/controlling the room temperature and at least one consuming device in the form of a radiator. In this case, each heating section features a flow restrictor that is arranged in the supply or return conduit of the heating section. This is intended to ensure a constant pressure level at the valves of each heating section.  
         [0006]     The adjustment of a constant pressure level at the valves is referred to as hydraulic balancing. Hydraulic balancing makes it possible to ensure a sufficient water distribution in the conduit network under varying operating conditions without exceeding permissible noise levels. The utilization of section control valves, flow regulators, differential pressure regulators and a controlled circulating pump makes it possible to ensure an economical water distribution in the system by means of hydraulic balancing in accordance with the publication “IKZ-Haustechnik”, Vol. 13, p. 48 ff., 1999. Due to these measures, the required energy is made available to all consuming devices, namely radiators, heat exchangers and the like, at all times in the form of a uniform volumetric flow at the same setting, for example, of the thermostatic valves. If no hydraulic balancing takes place, the following problems arise in addition to increased energy consumption: the rooms do not reach the desired temperature, system components are heated only with a certain time delay, the room temperature also fluctuates in the part load mode, and noise develops at the valves.  
         [0007]     A radiator/heat sink can only perform its function if it receives the optimal volumetric flow of the heat transfer medium or coolant. An excessively low volumetric flow results in a reduced heating/cooling capacity. However, excessive quantities of fluid delivered to a radiator/heat sink do not result in a proportional increase of the heating capacity, but rather only in slightly higher heat emission.  
         [0008]     It is known to pre-adjust valves, i.e., to define the through-opening of the valves in order to provide hydraulic balancing. In this case, the valves act as throttles such that the pressure level upstream of all valves is also identical in the full load mode when all the valves of all heating/cooling sections are completely open.  
         [0009]     However, known solutions for realizing hydraulic balancing are costly because they require additional construction measures. Furthermore, the volumetric flow is also limited by the valves, section gates or flow restrictors in the part load mode, for example, when no hydraulic balancing is required.  
       SUMMARY OF THE INVENTION  
       [0010]     Consequently, the invention is based on the objective of additionally developing a cooling and/or heating device of the type described in the preamble of claim  1  such that the aforementioned disadvantages are avoided by creating a simpler and more effective solution and improving the capacity of the cooling and/or heating device, particularly in the part load mode.  
         [0011]     This objective is attained with the characteristics disclosed in the characterizing portion of claim  1 , in connection with the characteristics of its preamble.  
         [0012]     Advantageous additional developments of the invention form the objects of the dependent claims.  
         [0013]     The invention is based on the notion of simply adjusting the valves, e.g., two-way valves or three-way valves, by means of a central control unit for regulating the heating and/or cooling demand of the units to be heated or to be cooled, if applicable, in connection with a temperature control circuit such that a slight modification of the software makes it possible to provide hydraulic balancing on demand with the valves that are already provided in the respective circuits.  
         [0014]     According to the invention, the valves are connected to a control unit for adjusting the valve openings, wherein sensors are provided in the individual circuits and the sensors form part of a control circuit of the control unit that adjusts the valves as a function of the signals transmitted from the sensors to the control unit such that hydraulic balancing between the individual circuits is achieved. This construction provides the enormous advantage of eliminating the need for any additional hydraulic balancing measures, for example, section gates, flow restrictors and the like. Furthermore, the valves no longer act as throttles, particularly in the part load mode in which the demand for hydraulic balancing is comparatively low, so that the heating capacity of the consuming devices, i.e., of the radiators/heat sinks, heat exchangers or the like, is significantly increased.  
         [0015]     Hydraulic balancing can be automatically controlled if sensors are provided in the individual circuits that cooperate with the control unit and together with this control unit determine whether or not hydraulic balancing is required. Corresponding control signals for the valves that either initiate hydraulic balancing or merely adjust the valve opening in accordance with the heating/cooling demand are then generated based on the information obtained from the sensors.  
         [0016]     In this connection, the sensors can be arranged in the circuit in many different ways. For example, one respective sensor is provided upstream and downstream of the consumer.  
         [0017]     The sensor can be realized in the form of a temperature sensor and/or pressure sensor. For example, if the temperature is used as the basis for determining whether or not hydraulic balancing is required, it is advantageous to arrange a sensor upstream and downstream of the radiator/heat sink, heat exchanger or the like.  
         [0018]     In order to prevent the system from overshooting when hydraulic balancing is initiated, the valves are adjusted at certain time intervals and in predetermined increments with respect to the extent of the adjustment of the valve opening.  
         [0019]     With the exception of the valve, no further flow restrictors are provided in the respective circuits of the conduit network in order to obtain the advantages of the invention in their entirety.  
         [0020]     According to an embodiment of the invention, the valve cooperates with a servomotor that receives its control signals from the control unit and moves the actuator of the valve into the position defined by the control signal.  
         [0021]     In this case the valve is in particular operated such that it does not act as a flow restrictor/throttle when it is completely open. Due to this measure, the volumetric flow that is generated by a pump in the conduit network and defined by the respective conduit cross section can be used for heating or cooling purposes without the valve generating a resistance. This significantly increases the capacity of the cooling and/or heating device in the part load mode. Measurements showed that it is possible to increase the capacity by approximately 30 percent.  
         [0022]     The control unit preferably features a first control circuit for controlling the temperature and a second control circuit for controlling hydraulic balancing of the circuits.  
         [0023]     In this case, the control unit is provided, in particular, with a minimum selector that is connected to the outputs of the control circuit such that the control signals for the valve or the valves resulting from both control circuits are fed to the control unit via the minimum selector, and the valve assumes the minimal setting if different control signals are received.  
         [0024]     Other advantages, characteristics and possible applications of the present invention, namely a cooling and/or heating device, are disclosed in the following description in connection with the embodiments illustrated in the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]     The invention is described in greater detail below with reference to the embodiments illustrated in the drawings. The terms and the respectively assigned reference symbols shown in the list of reference symbols are used in the description, the claims, the abstract and the drawings. In these drawings:  
         [0026]      FIG. 1  shows a schematic circuit diagram of the heating device according to the invention in a building with several floors;  
         [0027]      FIG. 2  shows a schematic sequence of the hydraulic balancing control in connection with a conventional temperature control according to the invention, and  
         [0028]      FIG. 3  shows another embodiment of the invention, in which the respective valve also serves as a section gate. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]      FIG. 1  shows a schematic building  2  that comprises a utility room  4  with a heat source  6  accommodated therein on the basement floor, and three heated floors  8   a - 8   c , namely a first floor  8   a , a second floor  8   b  and a third floor  8   c . Three partial sections  12   a - 12   c  installed in the building  2  form part of a central heating system  10  and act as first heating circuits. The partial section  12   a  is installed on the first floor  8   a , the partial section  12   b  is installed on the second floor  8   b  and the partial section  12   c  is installed on the third floor  8   c.    
         [0030]     The partial sections  12   a - 12   c  respectively include a flow conduit  18  and a return conduit  20  that extend separately from one another. The partial sections  12   a - 12   c  are connected to the heat source  6  by means of risers  14  and  16  that also have a flow conduit and a return conduit.  
         [0031]     Three heating sections  32 - 36  that act as second heating circuits are connected to the respective partial sections  12   a - 12   c  on each heated floor  8   a - 8   c . Each heating section  32 - 36  is connected to the flow conduit  18  of the assigned partial section  12   a - 12   c  with a supply conduit  24  and to the return conduit  20  of the assigned partial section  12   a - 12   c  with a return conduit  30 . The first two heating sections  32  and  34  respectively feature only one consumer in the form of a radiator  22 , while two radiators  22  are arranged in series in the third heating section  36  shown. The flow conduit  18  and the return conduit  20  of a partial section  12   a - 12   c  have the same conduit diameter.  
         [0032]     A valve  28  arranged in the supply conduit  24  of each heating section  32 - 36  serves to regulate the room temperature and can be respectively actuated by means of an actuator  26 .  
         [0033]     One respective temperature sensor  38  is arranged upstream and downstream of each radiator  22  if hydraulic balancing between the individual heating sections  32 - 36  needs to be achieved. Temperature sensors  38  are only provided for the series-connected radiators  22  in the partial section  12   c , and in this case in the third heating section  36 , upstream of the first radiator  22  and downstream of the last radiator  22  of this heating section  36 . Naturally, only one temperature sensor  38  in the flow conduit and the return conduit of a partial section  12   a - 12   c  would also suffice to provide hydraulic balancing between the individual partial sections  12   a - 12   c.    
         [0034]     The temperature sensors  38  cooperate with a control unit  40  and deliver the corresponding flow and return temperatures of the heating sections  32 - 36  or  12   a - 12   c , respectively.  
         [0035]     The servomotors  26  are controlled by the control unit  40 . The temperature sensors  38 , the control unit  40  having a regulator  48 , and the servomotors  26  with the valves  28  form part of a control circuit for hydraulically balancing the central heating system  10 .  
         [0036]     Other conventional sensors  42  are also provided and customarily form a control circuit for regulating the temperature in the rooms on the floors  8   a - 8   c , together with the control unit  40  which has another regulator  46 , the servomotors  26 , and the valves  28 .  
         [0037]     For example, different flow speeds of the heat transfer medium normally occur in the central heating system  10  if the majority of valves  28  are open. An essentially constant flow speed is adjusted in the central heating system  10  due to the hydraulic balancing control circuit. Since the flow speeds are now essentially constant, pressure fluctuations are prevented within the conduit network of the central heating system  10 , particularly in the supply conduits  24  and the return conduits  30  of each heating section  32  and therefore at the valves  28 . Consequently, the hysteresis of the valves  28  relative to one another remains unchanged. This provides the advantage that the room temperature is controlled isochronously.  
         [0038]      FIG. 2  shows the schematic sequence of the hydraulic balancing control in cooperation with the temperature control, with  FIG. 2  showing only the control of one room  8  and a circuit  74 - 78 , described further below, in order to provide a better overview.  
         [0039]     The temperature control is obtained conventionally: the sensor in the form of a temperature sensor  42  cooperates with the temperature regulator  46 . The actual temperature Tit in the room  8  is delivered to the temperature regulator  46  by the temperature sensor  42 . The desired nominal temperature T soll  for the room  8  is adjusted beforehand and stored in the control unit  40 . This nominal temperature T soll  is made available to the temperature regulator  46  by a memory of the control unit  40 . A nominal value/actual value comparison results in an assigned control signal  50  for the servomotor  26  of the valves  28 . For example, if the nominal temperature T soll  is higher than the actual temperature T ist  during a heating process, the valve  28  needs to be opened such that the volumetric flow of the heat transfer medium and therefore the heat emission of the radiator  22  into the room  8  are increased.  
         [0040]     In addition to the temperature regulator  46 , another regulator  48  is also provided for hydraulic balancing on the floors  8   a - 8   c  and in the circuit  74 - 78  described further below, as well as between the floors  8   a  and  8   c . In this case, each temperature sensor  38  of a flow conduit and a return conduit is assigned to a device  52  that determines the temperature difference between the heat transfer medium upstream and downstream of the radiator  22  or upstream and downstream of the consuming device based on the temperatures delivered by the temperature sensors  38 . This temperature difference corresponds to an actual differential temperature T ist diff .  
         [0041]     The nominal differential temperature T soll diff  results from a characteristic that refers to a preadjusted temperature difference between the flow conduit and the return conduit of the radiator  22  or of consumers as a function of the opening position of the valve  28  and the flow conduit temperature. The nominal value T soll diff  is subject to a certain tolerance. The tolerance decreases proportionally with an increase in the number of active consumers and therefore the number of radiators  22  in operation, and increases proportionally with a decrease in the number of active consuming devices and therefore the number of radiators  22  in operation. The hydraulic balancing control signal of the regulator  48  is identified by the reference symbol  54 .  
         [0042]     If the differential temperature value T ist diff  lies within the tolerance value T soll diff , the control signal  54  corresponds to a value at which the flow cross section of the valve  28  is 100% open. If the differential temperature value T ist diff  lies outside the tolerance value T soll diff , the control signal  54  corresponds to a value that ensures hydraulic balancing, i.e., a value that must be smaller than the value of the control signal  50  of the temperature regulator  46 .  
         [0043]     The value of the control signal  54  of the regulator  48  for achieving hydraulic balancing therefore either corresponds to 100% of the opening cross section of the valve  28  or is smaller than the value of the control signal  50  of the temperature regulator.  
         [0044]     The control signals  50  and  54  are then fed to a minimum selector  44  such that only the lower value  56  of a control signal  50  or  54  is fed to the servomotor  26  of the valve  28 .  
         [0045]     The control unit  40  ensures that hydraulic balancing is adjusted in increments such that overshooting is prevented and the system is able to enter the transient state.  
         [0046]      FIG. 3  schematically shows another embodiment of the invention. In this case, a valve  96  acts as a section gate and is controlled in accordance with the valve  28  thus far described by means of a servomotor, not shown, in order to achieve hydraulic balancing, wherein the valve in the circuit  74  is identified by the reference symbol  88  and is provided in the form of a three-way valve.  
         [0047]      FIG. 3  shows a supply unit  58  that forms part of a central cooling and heating system  60 . Only one supply unit  58  is shown for reasons of simplicity. However, the cooling and heating system  60  is composed of several supply units  58  that are designed in accordance with the supply unit  58  shown, and each supplies one building.  
         [0048]     The main supply line  62  features a main flow conduit  64  and a main return conduit  66 . A distribution unit  72  is connected to the main supply line  62  by means of the supply conduit  68  and the return conduit  70 . The distribution unit  72  forms part of the supply unit  58 .  
         [0049]     The supply unit  58  furthermore comprises, for example, three circuits  74 ,  76  and  78 , namely a ventilation circuit  74 , a heating circuit  76  and a domestic water circuit  78 . Each of the three circuits  74 ,  76  and  78  features a flow conduit  80 , a pump  82  and a return conduit  84 . The circuits  74 ,  76  and  78  each form different hydraulic circuits. However, the circuits  74 ,  76  and  78  are generally known, so that a more detailed description seems unnecessary. Only the heating circuit  76  is described in an exemplary fashion below.  
         [0050]     In the detailed illustration of the heating circuit  76 , the heating circuit is provided in the form of an injection circuit and provided with several radiators  22 . A valve  28  is assigned to each radiator  22  in the supply conduit  86 . The supply conduit  86  of the radiator  22  is connected to the flow conduit  80  of the heating circuit  76 , and the return conduit  90  is connected to the return conduit  84  of said heating circuit.  
         [0051]     The flow conduit  80  and the return conduit  84  of the heating circuit  76  are connected to one another by a bypass  92 , into which a mechanical slide valve  94  is integrated. The position of the slide valve is not pre-adjusted, i.e., the valve is completely open and not adjusted.  
         [0052]     Another valve  96  for regulating the volumetric flow and therefore the flow temperature is arranged in the return conduit  84  of the heating circuit  76  downstream of the bypass  92 . Hydraulic balancing in accordance with the above-described embodiment is achieved between the individual circuits  74 - 78  by regulating/controlling the valve  96 . Temperature sensors  38  that cooperate with a control unit  40  realized analogously to the control unit described above are arranged in the flow conduit  80  and in the return conduit  84  for this purpose.  
         [0053]     The other valves  28  may—but do not necessarily have to—also be provided with sensors in the supply conduit  86  and return conduit  90  in order to achieve hydraulic balancing. It also suffices if hydraulic balancing is achieved between the circuits  74 ,  76  and  78 .  
       LIST OF REFERENCE SYMBOLS  
       [0000]    
       
         
           
               2  Building  
               4  Utility room  
               6  Heat source  
               8  Room  
               8   a - 8   c  Floors  
               10  Central heating system  
               12   a - 12   c  Partial sections  
               14  Riser flow conduit  
               16  Riser return conduit  
               18  Flow conduit of a partial section  
               20  Return conduit of a partial section  
               22  Radiator  
               24  Supply conduit of a heating section  
               26  Servomotor  
               28  Valve  
               30  Return conduit of a heating section  
               32  First heating section  
               34  Second heating section  
               36  Third heating section  
               38  Temperature sensor  
               40  Control unit  
               42  Additional sensors  
               44  Minimum selector  
               46  Temperature regulator  
               48  Hydraulic balancing regulator  
               50  Control signal for servomotor of temperature regulator  
               52  Device for determining a temperature difference  
               54  Control signal for hydraulic balancing  
               56  Control signal for minimum selector  
               58  Supply unit  
               60  Central cooling and/or heating device  
               62  Main supply line  
               64  Main flow conduit  
               66  Main return conduit  
               68  Supply conduit  
               70  Return conduit  
               72  Distribution unit  
               74  Ventilation circuit  
               76  Heating circuit  
               78  Domestic water circuit  
               80  Circuit flow conduit  
               80   a  Partial section of circuit flow conduit  
               82  Pump  
               84  Valve in circuit return conduit  
               86  Supply conduit of radiator  
               88  Valve  
               90  Return conduit of radiator  
               92  Bypass  
               94  Slide valve  
               96  Valve