Heat pump arrangement with a controllable heat exchanger

Abstract

The invention relates to a heat pump arrangement comprising a heat pump device (100), an evaporator circuit interface (200) for introducing liquid (230) to be cooled into the heat pump device (100) and for discharging cooled liquid (220) from the heat pump device (100), a condenser circuit interface (300) for introducing liquid (330) to be heated into the heat pump device and for discharging heated liquid (320) from the heat pump device, a controllable heat exchanger (700) for controllable coupling of the evaporator circuit interface (200) and of the condenser circuit interface (300), and a controller (400) for controlling the controllable heat exchanger (700) depending on an evaporator circuit temperature in the evaporator circuit interface (200) or a condenser circuit temperature in the condenser circuit interface (300).

Description

[0001] The present invention relates to heat pump applications and in particular to heat pump applications that can be used for cooling, heating or other purposes where heat needs to be pumped from one level to another.

[0002] Typical applications for heat pumps include cooling an area and / or heating an area. A heat pump, typically consisting of an evaporator, a compressor, a condenser, and an expansion valve, comprises an evaporator side and a condenser side for this purpose. Depending on the implementation, a heat pump is coupled with a heat exchanger on the evaporator side and / or a heat exchanger on the condenser side. When the heat pump is used as a cooling unit, the area to be cooled is the "useful side." This area could be, for example, an interior space such as a computer room or another room requiring cooling or air conditioning. The area to be heated could then be, for example, the exterior wall of a building or the roof surface, and another area to which the waste heat is to be transferred.If, on the other hand, the heat pump is used for heating, then the area to be heated is, in a sense, the "usage side" and the area to be cooled would be, for example, the ground, groundwater or something similar.

[0003] A problem with general heat pump applications is that the configuration doesn't account for the significant fluctuations in the ambient temperature of the area being heated, especially if it's located outdoors. For example, temperatures can drop to -20°C in winter and exceed 30°C in summer. Considering an application where a computer room is being air-conditioned, if the outside temperature is at or below the target temperature for the area being cooled, it would theoretically be sufficient to simply "open the windows" and not air-condition the computer room at all. However, this is problematic because computer rooms don't necessarily have windows, and if such cooling is used, maintaining a consistent temperature within the room becomes relatively difficult.For example, cold zones could form near windows, if any are present, while warm zones could develop far from the windows or behind certain computer racks, which might then not be adequately cooled. On the other hand, it is problematic that a heat pump configuration fails to take advantage of the fact that outside temperatures can fluctuate significantly and often fall within ranges where cooling is not normally necessary. For this reason, a configuration as it is generally used is designed for a worst-case scenario, such as a very hot summer day, even though such a hot summer day is, on average, very rare in Germany, and the vast majority of the time within a year, temperatures are at which the required cooling capacities are far below the assumed worst-case scenario.

[0004] DE 10 2012 208 174 B4 discloses a heat pump and a method for pumping heat in free cooling mode. The heat pump comprises an evaporator with an evaporator inlet and an evaporator outlet, a compressor for compressing the working fluid evaporated in the evaporator, and a condenser for condensing the evaporated working fluid compressed in the compressor. The condenser also has a condenser inlet and a condenser outlet. In free cooling mode, the evaporator inlet is connected to a return flow from an area to be heated. Furthermore, the condenser inlet is connected to a return flow from an area to be cooled.Furthermore, a switching device is provided to disconnect the evaporator inlet from the return flow from the area to be heated and to connect the return flow from the area to be cooled to the evaporator inlet, and furthermore to disconnect the condenser inlet from the return flow of the area to be cooled and, in addition, to connect the return flow from the area to be heated to a condenser inlet. This allows switching from free cooling mode to normal mode and back again. This efficiently takes into account that outside temperatures are often well below the maximum temperatures when the heat pump is not operated in the classic configuration, but rather in the configuration where the return flow from the area to be heated is connected to the evaporator inlet and the return flow from the area to be cooled is connected to the condenser inlet.In this free cooling mode, the system takes advantage of the fact that the return temperature from the area to be heated is already close to the temperature at which the evaporator is normally charged. Furthermore, it utilizes the fact that the return temperature from the area to be cooled is already within a temperature range suitable for the condenser of the heat pump. This results in a significant decrease in the temperature difference that the heat pump must overcome between the evaporator outlet and the condenser outlet compared to normal operation. Since the temperature difference that a heat pump must overcome is directly proportional to the quadratic value of the drive power consumed by the compressor, this leads to an increase in the heat pump's efficiency compared to a standard configuration without free cooling.

[0005] Depending on the application, however, the flexibility of the free cooling mode, in which the condenser inlets / outlets are actually switched, thus switching the liquid flow between the evaporator and condenser circuits, may be reduced. Furthermore, switching between the high-pressure condenser circuit and the low-pressure evaporator circuit, and vice versa, is necessary, which can be problematic depending on the design.

[0006] US 4,495,777 discloses the closest prior art for claim 1.

[0007] US 2006 / 0010893 A1 reveals a cooling system with low-capacity control.

[0008] WO 01 / 65188 A1 discloses a heat pump arrangement comprising a heat pump unit and an additional heat exchanger that thermally couples an evaporator circuit interface and a condenser circuit interface. The flow rate through the heat exchanger is controlled by actuating valves according to an air temperature.

[0009] The object of the present invention is to create a more flexible heat pump arrangement.

[0010] This problem is solved by a heat pump arrangement according to claim 1 or a heat pump system according to claim 1 2.

[0011] A heat pump assembly includes, among other things, a heat pump unit and an evaporator circuit interface for introducing the fluid to be cooled into the heat pump unit and for discharging the cooled fluid from the heat pump unit. The heat pump assembly further includes a condenser circuit interface for introducing the fluid to be heated into the heat pump unit and for discharging the heated fluid from the heat pump unit. In addition, a controllable heat exchanger is provided to couple the evaporator circuit interface and the condenser circuit interface in a controllable manner. Furthermore, a control system is provided to control the controllable heat exchanger depending on an evaporator circuit temperature at the evaporator circuit interface or depending on a condenser circuit temperature at the condenser circuit interface.Depending on the implementation, an evaporator circuit temperature sensor for detecting the evaporator circuit temperature, or a condenser circuit temperature sensor for detecting the condenser circuit temperature, or both sensors, may be present. In the latter case, the control system is preferably designed to control the controllable heat exchanger based on a difference between the evaporator circuit temperature and the condenser circuit temperature, or based on a comparison of the temperatures, in order to controllably couple the output side (i.e., the condenser circuit) and the input side (i.e., the evaporator circuit). However, according to the invention, no liquid coupling between the condenser circuit interface and the evaporator circuit interface is performed.Instead, only a thermal coupling of the outlet side and the input side is carried out via the heat exchanger, such that the working fluid in the condenser circuit interface is thermally coupled with the working fluid of the evaporator circuit interface, but is not directly fluid-coupled.

[0012] This ensures that control elements, which are preferably present in the controllable heat exchanger in addition to a conventional heat exchanger with two separate liquid paths, only ever have to switch in the same pressure area, i.e., only ever act in the condenser circuit interface or the evaporator circuit interface, but do not create a liquid short circuit between the two interfaces.

[0013] According to the invention, the control element is designed to cause, reduce, or suppress flow through one of the paths, depending on a setting of the control element. In the case of causing or suppressing flow, the control element is designed as a two-way control element (not according to the invention) that has an on and an off state. In the case of reducing the flow through one of the two paths, the control element is designed as a mixer, according to the invention, to direct a portion of the working fluid through the controllable heat exchanger and, depending on the implementation, to direct another portion of the working fluid around the controllable heat exchanger.

[0014] In the invention, the controllable heat exchanger comprises a heat exchanger unit with connections and two fluid-separated paths and at least one control element, wherein at least one connection of the heat exchanger unit is coupled to at least one connection of the at least one control element in order to cause, reduce, or prevent flow through one of the paths of the heat exchanger unit depending on a setting of the control element. Furthermore, the at least one control element is designed as a mixer.

[0015] In one embodiment, the at least one control element is designed as a passive mixer to reduce the flow through one of the paths of the heat exchanger unit, depending on the mixer's setting. "Passive" here means that the two-way switch or the mixer does not contain its own pump. In further embodiments, the passive elements also do not contain any valves.

[0016] Preferably, the controllable heat exchanger is installed such that one path of the controllable heat exchanger has continuous flow independently of the control system, and that the other path can be throttled relative to an on-state due to the use of the mixer. Depending on the implementation, because the controllable heat exchanger always has flow through it from at least one side, power electronics requiring cooling are arranged on the controllable heat exchanger or in at least thermal contact with it. Preferably, in this implementation, where the controllable heat exchanger is also used as a heat sink, i.e., for cooling necessary electronic components such as a frequency converter for the compressor motor, it is coupled such that the condenser circuit interface has continuous flow through one path of the controllable heat exchanger.This means that the waste heat from the electronic components is transported directly into the heat dissipation device typically provided for the heat pump arrangement, such as a cooling tower on the roof or on a shaded side of the building, even if free cooling is not activated and the other path of the heat exchanger unit is not being used.

[0017] The present invention is advantageous in that the inlet and outlet sides, i.e., the evaporator circuit and the condenser circuit, can be thermally coupled via the controllable heat exchanger, but are not coupled via the fluids. This allows different working fluids to be used in the condenser circuit on the one hand and in the evaporator circuit on the other. Furthermore, the requirements for the control element of the controllable heat exchanger are reduced compared to a switching of fluids with respect to the inlet and outlet sides, because the same pressures are always present and the pressure difference between the inlet side of the heat pump arrangement (i.e., the evaporator circuit) and the outlet side (i.e., the condenser circuit) cannot reach the same switching element.

[0018] Furthermore, the coupling of the two interfaces with the controllable heat exchanger provides additional flexibility. This allows not only the implementation of a free cooling mode, in which the returning working fluid from the recooler is used to directly cool the fluid to be cooled, but also, conversely, a controlled short circuit of the heat pump assembly. This short circuit can be beneficial when, without the heat pump, excessive cycling with frequent on / off cycles would occur. Such a situation can arise, for example, when the system is operating at partial load. If a high pressure increase is required from the system at a low cooling capacity—which can be the case, for instance, during partial load operation in a data center at high ambient temperatures—this would result in an excessively high volume flow rate and thus an excessively high mass flow rate.This would lead to the heat pump system cycling on and off frequently. By implementing the controllable heat exchanger using the controllable mixing valve, a controllable power bypass between the chilled and cooling water can now be created, which improves the part-load performance and effectively prevents cycling.

[0019] The heat pump arrangement according to the present invention thus offers, firstly, increased flexibility with regard to the connection of different liquids in the condenser circuit on the one hand and the evaporator circuit on the other. Furthermore, thermal coupling, instead of actual liquid coupling between the two sides, allows the use of simpler and more cost-effective control elements. Finally, thermal coupling not only enables the use of a free cooling mode to increase the efficiency of the heat pump, but also allows for the simultaneous use of a controllable power short circuit to improve the part-load performance of the system or to implement other system modes, such as service modes.

[0020] Preferred embodiments of the present invention are explained in detail below with reference to the accompanying drawings. These show: Fig. 1 a block diagram of a heat pump arrangement according to an embodiment of the present invention; Fig. 2a a heat pump arrangement (not the invention) with a two-way switch coupled to the evaporator circuit interface; Fig. 2b an implementation similar to the implementation of Fig. 2a , however with activated heat exchanger flow; Fig. 2c a similar implementation as in Fig. 2b , however with the compressor switched off; Fig. 3a an implementation of the heat pump arrangement (not the invention) with a two-way switch coupled to the evaporator circuit interface and indicating an activated flow through the heat exchanger> Fig. 3b an implementation similar to Fig. 3a , however with the flow through the heat exchanger deactivated; Fig. 4a an implementation of the heat pump arrangement with a control element coupled to the condenser circuit interface and showing an activated flow through the controllable heat exchanger, Fig. 4b an implementation similar Fig. 4a , however with deactivated flow through the heat exchanger to couple the evaporator circuit interface and the condenser circuit interface; Fig. 5a an embodiment of the heat pump arrangement (not the invention) with a two-way switch coupled to the condenser circuit interface and showing an activated flow through the heat exchanger, Fig. 5b a heat pump arrangement similar Fig. 5a , however with the flow through the controllable heat exchanger deactivated, i.e. in a mode that is not the free cooling mode; Fig. 6 a schematic representation of the controllable heat exchanger as a controllable mixer coupled with a two-way heat exchanger; Fig. 7 a tabular overview of different modes of heat pump arrangement; and Fig. 8 A schematic representation of the heat pump unit with an associated controllable heat exchanger for cooling the control electronics.

[0021] Fig. 1 Figure 1 shows a heat pump arrangement with a heat pump unit 100. The heat pump unit 100 further comprises an evaporator circuit interface 200 for introducing liquid 230 to be cooled into the heat pump unit 100 and for discharging cooled liquid 220 from the heat pump unit 100. The heat pump unit 100 further comprises a condenser circuit interface 300 for introducing liquid 330 to be heated into the heat pump unit 100 and for discharging heated liquid 320 from the heat pump unit 100. In addition, a controllable heat exchanger 700 is provided to controllably couple the evaporator circuit interface 200 and the condenser circuit interface 300. In certain implementations, an evaporator circuit temperature sensor 210 (VTS) is also provided for detecting an evaporator circuit temperature.Furthermore, a condenser circuit temperature sensor 310 (KTS) is provided to detect the condenser circuit temperature. In addition, the heat pump arrangement according to the present invention is equipped with a controller 400 for controlling the controllable heat exchanger 700, wherein this controller operates depending on the evaporator circuit temperature, also referred to as TWK, or depending on the condenser circuit temperature, also referred to as TWW. The controller can operate using either a single temperature, i.e., either the condenser circuit temperature TWW or the evaporator circuit temperature TWK. However, it is preferred that both temperatures are used, i.e., that two different temperature sensors are provided, in order to control the controllable heat exchanger via the control line 410 based on a comparison or a difference between the two temperatures.

[0022] Fig. 6 Figure 1 shows a preferred embodiment of the controllable heat exchanger according to the invention, which shows, on the one hand, a heat exchanger unit 710 and, on the other hand, a control element which is located in Fig. 6 is labelled 760, but this is in the Fig. 2a bis 5b The heat exchanger unit is designated 720, 730, 740, and 750. It comprises four inlets 711, 712, 713, and 714, where inlets 711 and 712 define a first path through the heat exchanger unit 710, and where inlets 713 and 714 define a second path through the heat exchanger unit 710. The two paths, i.e., the first and second paths, are thermally coupled, as is typical for heat exchangers, but are fluid-separated, so that no fluid can pass from the first path to the second path within the heat exchanger unit when the unit is fully functional. Each of the connections 711, 712, 713, 714 can be an input, with the other connection of the path then being an output, the property of a connection, whether it is an input or an output, can be determined by the flow direction of the working fluid flowing through it.The port through which the working fluid flows into a path of the heat exchanger unit 710 is the inlet, and the port from which the fluid flows out is the outlet. Depending on the implementation, the controllable heat exchanger thus comprises a heat exchanger unit with four ports and two fluid-separated paths, wherein at least one port is coupled to a control element, such as a two-way control element, and depending on a setting of the control element, flow through one of the paths is caused, reduced, or suppressed.

[0023] The control element, such as 720, 730, 740, 750, 760, is configured to cause flow through a path when the condenser circuit temperature is in a predetermined ratio to the evaporator circuit temperature or is lower than a predetermined condenser circuit threshold. Depending on the implementation, the controllable heat exchanger 700 is configured such that one path of the controllable heat exchanger has continuous flow regardless of the control, while another path of the controllable heat exchanger can be switched on or off, or throttled relative to an on state, by the control.

[0024] Depending on the implementation, as outlined below, the controllable heat exchanger 700 comprises a heat exchanger unit, namely the heat exchanger unit 710 from Fig. 6 for example and the Fig. 2a bis 5b . The control element of the controllable heat exchanger, namely e.g. the element 720 to 760, is fluidly coupled to a first path of the heat exchanger element, and the control element is furthermore fluidly coupled to the evaporator circuit interface 200.

[0025] Furthermore, the condenser circuit interface 300 is coupled with a second path of the heat exchanger element, so that the fluid to be heated exits from the second path and the heated fluid enters the second path after cooling in a heat sink.

[0026] A corresponding implementation, in which the controllable element is coupled to the first path of the heat exchanger unit 710, is described in the Fig. 2a , 2b , 2c , 3a , 3b depicted.

[0027] Here it shows Fig. 2a a preferred embodiment of the heat pump arrangement in which the heat pump unit 100 is coupled to the evaporator circuit interface 200, as represented by the lines 220, 230 in Fig. 2a The evaporator circuit interface 200 further comprises an evaporator pump PV, which is configured to pump cooled fluid discharged by the heat pump unit 100 into an area 600 to be cooled, which is, for example, a data center. This fluid has, in the case of the Fig. 2a In the example shown, the liquid has a temperature of 16 °C and is heated by the area to be cooled, e.g., to a temperature of 22 °C, as shown by the evaporator temperature sensor 210, which determines the temperature TWK. The heated liquid then enters the control element 720, which, together with the heat exchanger 710, forms the controllable heat exchanger 700. In the case of the Fig. 2a In the illustrated embodiment, free cooling is not activated. Instead, the fluid to be cooled is introduced into the heat pump unit 100 via line 230, bypassing the heat exchanger 710. This is because the temperature of an area to be heated, namely, for example, the recooler 500, which provides waste heat, e.g., on the roof of a building or on a shaded side of a building, is higher. Here, the temperature after recooling is still at the temperature in Fig. 2a In the illustrated embodiment, the temperature is 26 °C, as measured by the condenser circuit temperature sensor 310, which outputs the temperature signal TWW. Since the temperature of the recooled working fluid is 26 °C, which is above the liquid temperature level of 22 °C returned from the area to be cooled, a free cooling mode would offer no advantage. Instead, the free cooling mode is deactivated by not supplying liquid to the first path of the heat exchanger unit 710, as shown in the illustration. Fig. 2a The position of the two-way switch shown is an example of a control element.

[0028] It should also be noted that the condenser circuit interface 300 in Fig. 2a a pump 340 which is designed to bring the heated liquid 320, which for example has a temperature of 32 °C, to the recooler 500 or to the area to be heated.

[0029] Fig. 2b shows again the implementation of Fig. 2a However, control element 720 is now switched to free cooling mode or "free cooling plus" mode, since the temperature at the outlet of the recooler, as measured by temperature sensor 310, is now 18 °C, which is lower than the temperature returned by the data center. Therefore, the two-way switch in Fig. 2b The system is configured so that the first path of the heat exchanger element 710 is supplied with the fluid, thus enabling heat exchange within the heat exchanger unit 710. This is done, for example, as described in... Fig. 2b As shown, the temperature of the fluid coming from the area to be cooled is reduced from 22 °C to 19 °C. Therefore, the heat pump unit 100 has to work significantly less than in the comparison example of Fig. 2a The cooler outside temperature (the air has warmed up) Fig. 2b The temperature of only 13 °C was therefore effectively used to reduce the power required by the heat pump unit 100.

[0030] The control element 720 is located in the Fig. 2b The illustrated embodiment is designed as a two-way switch with one input and two outputs. Furthermore, one input of the two-way switch is connected to an output from the area to be cooled, for example, the data center 600. This output is typically also connected via the evaporator circuit interface 200, as shown schematically in Fig. 1 shown, provided, namely through input 201 of the evaporator circuit interface 200 of Fig. 1 In contrast, the output from the evaporator circuit interface to the area to be cooled is designated 202. Furthermore, the output of pump 240 is connected to output 202 of the evaporator circuit interface leading to the area to be cooled. In addition, the first output of control element 720 can be coupled to the first input of the first path of heat exchanger unit 710, as shown in Fig. 2b shown is to achieve the free cooling mode, or with the 230 input of the heat pump unit for the liquid to be cooled.

[0031] Furthermore, the second path of the heat exchanger unit is also connected via another connecting line 235 to the inlet 230 of the heat pump unit 100 for the liquid to be cooled.

[0032] Fig. 2c This shows another operating mode in which free cooling, due to the cold outside temperature of, for example, 10 °C, is so efficient that the entire data center can be cooled without any activity from the compressor in the heat pump unit 100. Therefore, the position of control element 720 in Fig. 2c as in Fig. 2b selected. However, the compressor is now switched off. If the outside temperature drops further, the PK 340 pump can also be throttled to ensure that the minimum temperature required by the customer, for example 16 °C, is maintained at the PV pump outlet. This means that in the Fig. 2c In the illustrated embodiment, the compressor of the heat pump unit 100 is switched off, but the evaporator-side inlet of the heat pump unit 100 is connected in such a way that the liquid to be cooled on line 230 and the cooled liquid on line 220 have the same temperature, namely, for example, a temperature of 16 °C.

[0033] Fig. 3a Figure 7 shows an alternative implementation of the controllable heat exchanger with the heat exchanger unit 710 and the control element 730. The first input of the first path of the heat exchanger unit 710 is now permanently connected to terminal 201 of the evaporator circuit interface 200 via a connecting line 236. Furthermore, the control element 730, which is still only connected to the evaporator circuit interface, now has two inputs and one output. The first input is located at the... Fig. 3a In the illustrated embodiment, where free cooling is active, the second input of the control element is not coupled to the line for the liquid to be cooled, 230, as indicated by the dotted line within the two-way switch 730. Instead, the second input of the control element is connected to the output of the first path of the heat exchanger unit 710, such that the liquid to be cooled flows continuously through the heat exchanger unit 710. This ensures that the temperature of, for example, 22 °C is maintained. Fig. 3a The temperature is reduced to 20 °C, so that free cooling, due to the relatively cool outside temperature of around 14 °C, already relieves the heat pump unit 100 of a certain amount of "work", since now only the liquid has to be cooled from 20 °C to 16 °C, but no longer from 22 °C to 16 °C. The control element 730 is in Fig. 3b shown in its other position. Here, the heat exchanger 710 is again continuously supplied from the condenser side, i.e., from the condenser circuit. However, on the evaporator circuit side, no liquid flow is now possible through the first path of the heat exchanger unit 710 because the outlet is no longer, as in Fig. 3a , but is now coupled with the first input. As it is in Fig. 3a As shown, the control of the control element 730, i.e., which input is connected to a particular output, is achieved by comparing the two temperatures TWK and TWW. If TWK is greater than TWW, as is the case with the control element 400, Fig. 1 Once determined, free cooling is activated, while then, as in Fig. 3b It has been shown that free cooling is deactivated when TWK is less than TWW, i.e., when the return temperature from the area to be cooled at connection 201 of the evaporator circuit interface 200 is less than the returned and cooled liquid in the condenser circuit at the outlet of the area to be heated 500, which is shown in Fig. 3b is referred to as a "cooling system for waste heat roofs". While the Fig. 2a , 2b , 2c , 3a , 3b The following illustrations show an arrangement of the control element 720, 730 in conjunction with the evaporator circuit interface, while the condenser circuit interface is rigidly coupled to the heat exchanger unit 710. Fig. 4a , 4b , 5a , 5ban arrangement of the control element in coupling with the condenser circuit interface 300, wherein the evaporator circuit sections 200 are in turn firmly coupled to the heat exchanger unit 710, so that the heat exchanger unit 710 is continuously supplied with the return flow of the data center, i.e. the area 600 to be cooled.

[0034] This is the case with the one in Fig. 4a and 4b In the illustrated embodiment, the first path of the heat exchanger unit 710 is continuously coupled to the evaporator circuit interface 200, while the second path, and in particular the input of the second path of the heat exchanger unit 710, is coupled to the control element, specifically to a first output of the control element, which has one input and two outputs. In the embodiment shown Fig. 4a In the illustrated embodiment, the temperature TWK is higher than the temperature TWW, so free cooling is activated. Therefore, the first output of the control element is coupled to the input, and the liquid to be heated flows through the heat exchanger 710 to be cooled from, for example, 17 °C at the temperature shown. Fig. 4a In the example shown, the fluid is heated to 21 °C, which simultaneously cools the fluid to be cooled, fed into the heat pump unit on line 230, from 22 °C to 18 °C. The heated fluid is then fed into the heat pump unit 100 via line 330 at the outlet of the second path of the heat exchanger unit 710 and heated there, for example, to only 23 °C. The heated fluid is then discharged from the heat pump unit at line 320 into the condenser circuit interface and into pump 340, which finally delivers the fluid to the recooler or the area to be heated 500. There, sufficient energy is released into the air to ensure that the fluid at the outlet of the recooler has a temperature of, for example, 17 °C.

[0035] If, on the other hand, it is determined that the evaporator circuit temperature TWK is lower than the condenser circuit temperature TWW, as determined by sensors 310 and 210 respectively, the control element is switched to the position of Fig. 4b , in which free cooling is deactivated and the second path of the heat exchanger unit 710 is no longer supplied with fluid 330 to be heated. Instead, the fluid to be heated is fed past the heat exchanger unit 710 into the heat pump unit 100. Thus, the output 302 of the condenser circuit interface 300 is connected to the recooler or to the area to be heated 500. In addition, the return flow from the area to be heated is connected to an input 303 of the condenser circuit interface. The condenser circuit temperature sensor 310 is designed to measure the temperature of the fluid in the port 303. The input of the control element is connected to the input 303 of the condenser circuit interface 300, regardless of the position of the temperature sensor 310. The first output is, as shown in Fig. 4a As shown, in the case of free cooling, the first outlet is connected to the inlet, and the first outlet is further connected to the first port of the second path of the heat exchanger unit 710. In contrast, the second outlet in the Fig. 4b The operating mode shown is connected to input 330 of the heat pump unit for the fluid to be heated. Fig. 5a and 5b show an alternative implementation of control 750, which now does not function as in Fig. 4a and 4b The control element 750 is not connected to the first input of the second path of the heat exchanger unit 710, but to the output of the second path of the heat exchanger unit 710. The control element 750 has two inputs and one output. The first input of the control element 750 is connected to the one in Fig. 5b In the illustrated embodiment, where free cooling is deactivated and normal mode is active, the output is connected to the line 330, which in turn is connected to the line for the fluid to be heated, which is fed into the heat pump unit 100. The second input of the control element is permanently connected to the output of the second path of the heat exchanger unit 710 and, in free cooling mode, is connected to one output of the control element 750.

[0036] Although in the Fig. 2a bis 5b Whereas the control element 720, 730, 740, 750 has been represented as a two-way switch having either two inputs and one output or two outputs and one input, according to the invention the two-way switch is also implemented as a mixer. The mixer is in Fig. 6 The unit shown at 760 has one inlet and two outlets. The mixer allows a portion of the working fluid, for example 70%, to bypass the heat exchanger unit 710, while the other portion, for example 30%, is directed into the first path of the heat exchanger unit 710.

[0037] For example, a working fluid with a temperature of 20 °C is raised to 24 °C by the heat exchanger unit 710. This results in a total temperature of 21 °C at the branch point or combination point, where the output 712 of the first path is connected to the line for the fluid to be cooled, 230. By implementing the control element 760 as a mixer, a configuration such as that described in Fig. 2a As shown, the temperature to be cooled is warmed to achieve a special operating mode in which the heat pump unit 100 is subjected to a higher load than actually necessary, which is particularly advantageous in certain cases, e.g. to avoid short cycling of the heat pump unit 100. In the Fig. 3 In the illustrated embodiment, the control element 730 can also be replaced by a mixer, which ensures that a certain proportion, namely, for example, the smaller proportion, enters the second input of the control element, so that partial heating can also be achieved when the mixer is placed in the position shown in Fig. 3a and 3b shown for control element 730.

[0038] Similar implementations for the mixer can also be found for controls 740 and 750. Fig. 4a bis 5b This must be done to achieve a corresponding mixing effect even when the control element is placed on the condenser circuit interface side.

[0039] Fig. 8 Figure 1 shows a specific implementation of the heat pump unit 100. In one embodiment, the heat pump unit 100 comprises an evaporator 110. Working fluid is evaporated in the evaporator. The evaporated working fluid is compressed by a compressor 120, preferably a motor with a radial impeller, and thus raised to a higher temperature level. The compressed vapor is then fed to a condenser 130. Depending on the implementation, a throttle 140 can also be provided to regulate the working fluid flow. If water is used as the working medium within the heat pump unit, a passive self-regulating throttle can be used. If, on the other hand, so-called chemical refrigerants, i.e., refrigerants that differ from water, are used, a switchable throttle bypass can be implemented in the throttle 140 instead of a passive self-regulating throttle.

[0040] It should also be noted that the heat pump unit 100 does not only contain such a stage as is found in Fig. 8 The heat pump unit can be implemented not only as represented by elements 110 to 140, but it can also contain two or more stages in any combination. The one or more stages are connected to the evaporator circuit interface on the inlet side (evaporator side) and to the outside world via the condenser circuit interface on the outlet side (condenser side). Fig. 8 Figure 1 further shows an implementation of the controllable heat exchanger 700 with a control element, for example, a control element 720, 730, 740, 750, 760, and an associated heat exchanger unit 710. Preferably, the control electronics or an electrical circuit unit 123, which, for example, includes a frequency converter circuit for the stator-side coil control of the electric motor in the compressor 120, power electronics, a rectifier, or control electronics, is placed on the heat exchanger unit 710. This ensures that the control electronics are always kept at the temperature of the heat exchanger unit 710 or, since they themselves would become significantly hotter, are cooled by the heat exchanger unit 710. Alternatively, placement in a thermal interaction arrangement is also possible, e.g.,By means of a special heat transfer device, a cooling effect also occurs even if the control electronics on the one hand and the heat exchanger unit 710 on the other hand are not in direct contact. The heat transfer device preferably has a thermal conductivity that is at least ten times higher than that of an air gap of the same length. Since, in a preferred embodiment, the heat exchanger unit 710 is always supplied with fluid from either the condenser circuit or the evaporator circuit, cooling always takes place. Even the temperatures in the condenser circuit, which can exceed 20 °C, are quite sufficient as cooling temperatures for the electronics assembly. Therefore, it is preferred to couple the heat exchanger unit 710 to the condenser circuit interface in such a way that the heat exchanger unit 710, or rather its secondary path, is always supplied with fluid from the condenser circuit.This means that the waste heat from the control electronics goes directly into the condenser circuit and thus into the heat recovery device without first having to be "pumped" from the evaporator circuit into the condenser circuit.

[0041] Fig. 7 shows a tabular overview of different modes, which can be selected, for example, with a two-way switch, as found in the Fig. 2a bis 5b as has been shown, can be achieved.

[0042] Particularly in a cold temperature range, where the air temperature is below 10 °C and the sensor values ​​indicate that the hot water temperature (TWK) is greater than the hot water temperature (TWW), free cooling is active. Furthermore, the controllable heat exchanger is flowed through from both sides and is therefore active. Moreover, as described in Fig. 2c As an example, the compressor is deactivated, i.e., switched off. Temperature control can be achieved, for example, by regulating the condenser-side pump 340 contained in the condenser circuit interface 300. If it is detected that the temperature of the cooled liquid is falling below a setpoint temperature, the pump 340 can be throttled back. Conversely, if it is detected that the temperature is rising too high, the pump 340 can be sped up again. Alternatively or additionally, a fan typically found in the recooler 500 can also be sped up or sped down to achieve more or less cooling capacity.

[0043] In a moderately cold temperature range, for example between 10°C and 16°C, free cooling is also active. In addition, the compressor is active, and the temperature supplied to the data center, or the area to be cooled, can be regulated by controlling the speed of the compressor's radial impeller. If higher cooling capacity is required, the speed is increased. Conversely, if lower cooling capacity is required, the speed of the radial impeller is reduced.

[0044] In normal operating mode, which is activated in a warm temperature range (e.g., above 16 °C), it is typically observed that the temperature TWK is lower than the temperature TWW. The controllable heat exchanger 710 is then deactivated, and cooling capacity can again be controlled via the rotational speed of the radial wheel. However, free cooling is not active in this mode, i.e., in the warm temperature range.

[0045] As a special mode in which, according to the invention, a mixer, as described in relation to Fig. 6 as described, can be used in the positions defined by elements 720 to 750 in the Fig. 2a bis 5b As depicted, a controllable short circuit can be achieved between the output (condenser circuit) and the input (evaporator circuit) of the heat pump unit. Particularly at high ambient temperatures and relatively low power demands from the data center (e.g., operating only under partial load), the control system would otherwise switch to on-off cycling, which is undesirable for various reasons. Therefore, according to the invention, the special mode with controllable short circuit is activated, for example, by a specific cycling frequency.If an excessively high cycling frequency is detected, the controllable short circuit is activated. This means that a typically smaller portion, i.e., less than 50% of the flow rate, is fed into the corresponding first or second path of the heat exchanger unit and recombined with the other (typically larger) portion at the heat exchanger unit's outlet. This mixing effect, which is described in... Fig. 6 as 70 / 30 - as already described, it may be possible, as in Fig. 7 As shown in the last row of the table, the flow rate can be controlled depending on the implementation, for example, from 1% / 99% control to 51% / 49% control. In any case, it is preferred that the larger part of the flow bypasses the heat exchanger element 710 and only the smaller part of the flow passes through the heat exchanger element 710, whereby, as mentioned, the proportion of the smaller flow is controllable from 0 to 50%, depending on the mixer design.

[0046] In preferred embodiments of the free cooling system Plus, a heat exchanger and a three-way switch are installed. The three-way switch can be installed on either the cold water or hot water side and is intended to open or close the flow through the heat exchanger. Depending on the implementation, the PV 240 or PK 340 pumps may not be present. Furthermore, additional heat exchangers can also be used, for example, at the outlet of the PV 240 pump or at the outlet of the PK 340 pump, although these heat exchangers are not included in the standard configuration. Fig. 3a and are not shown in the other figures, for example. Water as a refrigerant offers the advantage for free cooling Plus, despite its poor volumetric cooling capacity, that the volume flow and pressure ratio can be adjusted using a speed-controlled radial compressor, thus creating a near-ideal operating point for the system across a wide range of applications. This can be achieved even with small cooling capacities below 50 kW. In the implementations shown, water is cooled from, for example, 20 °C to 16 °C, although other temperatures are also possible, such as cooling to 20 °C from a higher temperature of 26 °C. The general aim is always to achieve the desired cooling capacity with the lowest possible energy expenditure, allowing the cooling capacity to be released back into the environment, depending on the outside temperature.If the water coming from the roof (cooler) is at a temperature sufficient to allow the entire cooling capacity to be transferred from the chilled water to the cooling water via the upstream heat exchanger, no compressor work is performed. If ambient temperatures rise further, preventing the production of 20°C chilled water without compressor work, the compression chiller is activated with capacity control to provide the missing portion, for example, 3°C or 50% of the capacity. If outside temperatures continue to rise and the cooling water reaches temperatures of, for example, 25°C or higher, virtually no energy can be transferred through the heat exchanger. The entire cooling capacity must now be provided by the compression chiller.If the cooling water temperatures continue to rise above 26 °C in this range, the three-way switch must block the flow through the heat exchanger on at least one side; otherwise, the refrigeration system would have to provide even more cooling capacity than required by the application.

[0047] In specific alternative embodiments, it is preferred that the control, i.e., whether or not the heat exchanger is circulated, depends solely on the temperatures TWW and TWK. Specifically, when the temperature TWW is lower than TWK, the heat exchanger unit is circulated. If the temperature in the evaporator is higher than the supply temperature on the chilled water side or customer side, the compressor must operate. Conversely, if the temperatures in free cooling mode are below the required customer temperature, here 16 °C, the roof-mounted fan and ultimately the pumps can be throttled back.

[0048] In a preferred embodiment of the present invention, a throttle is used for free cooling plus, which operates reliably even without a pressure difference or from a small pressure difference of less than 10 mbar up to the maximum pressure stroke. This ensures that the refrigerant flow from the condenser to the evaporator is balanced when a corresponding fluid balancing function is required. This contrasts with known refrigeration systems that have electronic throttles which only operate at pressure differences of several bar.

[0049] Furthermore, the invention proposes using a turbomachine as a compressor, so that the required pressure differential and the power, such as the mass flow rate, can be precisely controlled via the rotational speed. Preferably, water is also used as the refrigerant, enabling small pressure differentials of less than 100 mbar across the entire operating range, and the extreme volume differences between vapor and liquid allow for the integration of a self-regulating throttle. However, in order to also be able to work with so-called chemical refrigerants, i.e., refrigerants other than water, it is preferred to use a self-regulating throttle instead of the passive one described in [reference to invention]. Fig. 8 The diagram shows how to use a switchable throttle bypass to return a refrigerant from the high-pressure side to the low-pressure side.

[0050] As has already been shown, and based on Fig. 6 As previously explained, the invention proposes implementing the three-way switch as a mixer to optimize the system's part-load performance. For compression, turbomachines are preferably used, which have a speed-dependent volume flow rate and a speed-dependent pressure increase. The mass flow rate is crucial for the cooling capacity. If a high pressure increase is required from the system at low cooling capacity (partial load in the data center and high ambient temperatures), this results in an excessively high volume flow rate and thus an excessively high mass flow rate. This leads to cycling of the system (on...off...on). If the three-way switch is replaced by a mixer, a controllable power bypass between the chilled and cooling water can be created, which improves the part-load performance and effectively prevents cycling.

[0051] Preferably, the heat exchanger unit in the controllable heat exchanger is continuously traversed by a single flow path. This makes the heat exchanger ideally suited for cooling power electronics. When the mixer is moved to the cold water side, the electronics direct their losses directly into the cooling water side, i.e., into the condenser circuit. This has the advantage that the heat pump unit does not first have to transfer the heat loss to the output side via compressor work. Therefore, the rectifiers for the frequency converter circuits are preferably arranged on the heat exchanger unit, i.e., in thermal contact with the controllable heat exchanger.

[0052] A method for manufacturing a heat pump arrangement with a heat pump unit comprises the following steps: Introducing a liquid to be cooled into the heat pump unit and discharging the cooled liquid from the heat pump unit; introducing a liquid to be heated into the heat pump unit and discharging the heated liquid from the heat pump unit; and coupling a liquid cooled by a heat sink in a controllable and thermal manner with the liquid to be cooled via a controllable heat exchanger, depending on an evaporator circuit temperature that has a temperature of the liquid to be cooled or the cooled liquid, or depending on a condenser circuit temperature that has a temperature of the liquid to be heated or the heated liquid or the liquid cooled by the heat sink. Although certain elements are described as device elements, it should be noted that this description is equally to be regarded as a description of steps of a process and vice versa.

[0053] Furthermore, it should be noted that a control system, for example, by element 400 in Fig. 1The invention can be implemented as software or hardware. The control system can be implemented on a non-volatile storage medium, a digital or other storage medium, in particular a floppy disk or CD with electronically readable control signals that can interact with a programmable computer system to execute the corresponding method for operating a heat pump. In general, the invention thus also includes a computer program product with program code stored on a machine-readable medium for carrying out the method, provided the computer program product runs on a computer. In other words, the invention can also be realized as a computer program with program code for carrying out the method, provided the computer program runs on a computer. Reference symbol list

[0054] 100 Heat pump unit 1 10 Evaporator 120 Compressor 123 Control electronics 125 Electronic control line 130 Condenser 140 Expansion valve 200 Evaporator circuit interface 201 Return from area to be cooled 202 Supply to area to be cooled 210 Evaporator circuit temperature sensor 220 Cooled liquid 230 Liquid to be cooled 235 Connecting line 240 Pump in the evaporator circuit interface 300 Condenser circuit interface 302 Supply to area to be heated 303 Return from area to be heated 310 Condenser circuit temperature sensor 340 Pump in the condenser circuit interface 400 Control unit 410 Control line 500 Area to be heated 600 Area to be cooled 700 Controllable heat exchanger 710 Heat exchanger unit 71 1 Inlet first path 712 Outlet first path 713 Inlet second path 714 Output second way 720 Two-way switch 730 Two-way switch 740 Two-way switch

Claims

1. Heat pump arrangement, comprising following features: a heat pump device (100); an evaporator cycle interface (200) for inputting liquid to be cooled (230) into the heat pump device (100) and for outputting cooled liquid (220) out of the heat pump device (100); a condenser cycle interface (300) for inputting liquid to be heated (330) into the heat pump device and for outputting heated liquid (320) out of the heat pump device; a controllable heat exchanger (700) for controllably coupling the evaporator cycle interface (200) and the condenser cycle interface (300); and a control (400) for controlling the controllable heat exchanger (700) in dependence on an evaporator cycle temperature in the evaporator cycle interface (200) or a condenser cycle temperature in the condenser cycle interface (300), wherein the controllable heat exchanger (700) comprises a heat exchanger unit (710) with terminals (711-714) and two fluidically separated paths and at least one control element (760), wherein at least one terminal of the heat exchanger unit (710) is coupled to at least one terminal of the at least one control element (760) in order to effect, reduce or prevent flow through one of the paths of the heat exchanger unit (710) in dependence on a setting of the control element (760), and wherein the heat pump device (100) comprises a compressor (120) that is configured to be switched off when the cooled liquid (220) falls below a predetermined temperature or when the heated liquid (320) exceeds a predetermined temperature, characterized in that the at least one control element (760) is configured as mixer (760),and the control (400) is configured to detect switch-off events and to activate, at a frequency of the switch-off events with respect to a time period, a controllable short circuit in the controllable heat exchanger (700) to reduce a frequency of the switch-off events with respect to the time period or to eliminate the switch-off events completely.

2. Heat pump arrangement according to claim 1, wherein the at least one control element (760) is configured as passive mixer to reduce the flow through one of the paths of the heat exchanger unit (710) in dependence on the setting of the mixer.

3. Heat pump arrangement according to claim 1 or 2, in which the control (400) is configured to control the control element (760) such that the flow is effected through the path when the condenser cycle temperature (TWW) is at a predetermined ratio to the evaporator cycle temperature (TWK) or lower than a predetermined condenser cycle temperature threshold.

4. Heat pump arrangement according to any one of the preceding claims, in which the controllable heat exchanger (700) is configured such that a path of the controllable heat exchanger can be continuously flowed-through independent of the control (400) and another path of the controllable heat exchanger can be switched on or off or can be throttled with respect to an on-state by the control (400).

5. Heat pump arrangement according to any one of the preceding claims, in which the controllable heat exchanger (700) is configured to heat the liquid to be cooled (230) in the evaporator cycle interface (200) by means of a controllable short circuit using the liquid to be heated (330) in the condenser cycle interface (300) or using the heated liquid (330) in the condenser cycle interface (300) to increase a power requirement for the heat pump device (100) with respect to a power requirement of a region to be cooled (600) being connected to the evaporator cycle interface (200).

6. Heat pump arrangement according to any one of the preceding claims, in which the control (400) is configured to detect a state of the heat pump arrangement or the heat pump device (100), in which a controllable short circuit results in an improved operating behavior of the heat pump device (100), wherein the control (400) is configured to controllably short-circuit the controllable heat exchanger (700) only when the state of the heat pump arrangement or of the heat pump device (100) has been detected by the control (400).

7. Heat pump arrangement according to any one of the preceding claims, in which the mixer (760) is configured to bring, in a controllable short circuit, a first portion of a liquid that can be circulated in the condenser cycle interface (300) or the evaporator cycle interface (200) into a thermal operative connection to a liquid of the respective other interface and to bring a second portion of the liquid not into a thermal operative connection, wherein the first portion is smaller than the second portion.

8. Heat pump arrangement according to claim 7, in which the mixer (760) is controllable to control a ratio of the first portion to the second portion and that is in dependence on an operating behavior of the heat pump device (100).

9. Heat pump arrangement according to any one of the preceding claims, in which the evaporator cycle interface (200) is configured to be coupled to the region to be cooled (600) directly or via a heat exchanger or in which the condenser cycle interface (300) is configured to be coupled to the region to be heated (500) directly or via a heat exchanger.

10. Heat pump arrangement according to any one of the preceding claims, in which the evaporator cycle interface (200) is configured to hold a first operating liquid, in which the condenser cycle interface (300) is configured to hold a second operating liquid, wherein the second operating liquid differs from the first operating liquid, or in which the second operating liquid is CO2 and the first operating liquid is water or wherein the first operating liquid is water or CO2 and the second operating liquid is a water glycol mixture.

11. Heat pump arrangement according to any one of the preceding claims, in which the heat pump device (100) comprises one or several stages, wherein one stage comprises an evaporator (110), a compressor (120), a condenser (130) and a throttle (140), wherein the stage is configured to use water as operating medium and wherein pressure differences between the evaporator (110) and the condenser (130) are below 300 mbar in the entire operating range, wherein the compressor (120) comprises a radial wheel that is speed-controllable in dependence on a requested power of the heat pump device and wherein the throttle (140) is a self-regulating passive throttle, or in which the heat pump device (100) comprises one or several stages, wherein one stage comprises an evaporator (110), a compressor (120), a condenser (130) and a throttle (140), wherein the stage is configured to use a chemical medium as operating medium, in which a pressure difference between the evaporator (110) and the condenser (130) is greater than 5 bar and wherein the compressor (120) comprises a radial wheel that is speed-controllable in dependence on a requested power of the heat pump device and wherein the throttle (140) comprises a switchable throttle bypass in order to bring the operating medium from the condenser (130) back into the evaporator (110).

12. Heat pump system, comprising following features: a region to be cooled (600); a region to be heated (500); a heat pump arrangement according to any one of claims 1 to 11, wherein the evaporator cycle interface (200) of the heat pump system is coupled to the region to be cooled (600), wherein the condenser cycle interface (300) is coupled to the region to be heated (500).

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