HEAT PUMP SYSTEM AND METHOD FOR OPERATING SUCH A HEAT PUMP SYSTEM

Description

[0001] The invention relates to a heat pump system according to the preamble of patent claim 1 and to a method for operating such a heat pump system according to the preamble of patent claim 10.

[0002] A heat pump system of the type mentioned at the outset is known from document EP 3 351 868 A1, wherein in this solution, viewed in the operating flow direction of the heating circuit medium, a check valve is provided in particular which is connected downstream of the heating circuit pump and upstream of the secondary side and is designed to close when the heating circuit medium flows opposite to the operating flow direction, and wherein a degassing device is connected downstream of the secondary side in the operating flow direction.

[0003] Another, similar heat pump system is known from document DE 10 2011 011 210 A1. This heat pump system consists of a heat exchanger having a primary side and a secondary side, a heat pump circuit for a heat pump circuit medium flowing through the primary side of the heat exchanger, and a heating circuit for a heating circuit medium flowing through the secondary side of the heat exchanger, wherein a heating circuit pump is connected upstream of the secondary side of the heat exchanger in the operating flow direction of the heating circuit medium. The aforementioned heating circuit medium is typically, and will also preferably be, water. Furthermore, here and in the following, the heating circuit medium is pumped through the heating circuit in only one direction when the heat pump system is used as intended, namely in the aforementioned operating flow direction.

[0004] The invention is based on the object of improving a heat pump system of the type mentioned above. In particular, a heat pump system is to be created that automatically prevents further flow in the heating circuit in the event of a gas leak in the heat exchanger.

[0005] This problem is solved with a heat pump system of the type mentioned above by the features listed in the characterizing part of patent claim 1. In terms of method, this problem is solved according to the characterizing part of patent claim 10.

[0006] According to the invention, it is therefore provided that the degassing device is designed to prevent the flow of the heating circuit medium in the operating flow direction from a predefined gas quantity in the heating circuit medium, wherein the degassing device comprises a float. In terms of the method, it is thus provided that, from a predefined gas quantity of the heat pump circuit medium in the heating circuit medium, on the one hand, the check valve closes, and on the other hand, the degassing device prevents the flow of the heating circuit medium in the operating flow direction.

[0007] In other words, the heat pump system according to the invention is characterized in that the flow of the heating circuit medium is automatically prevented if a gas leak occurs at the heat exchanger, i.e., a passage of, in particular, flammable heat pump circuit medium from the primary to the secondary side of the heat exchanger. On the one hand, the check valve ensures that the heat pump circuit medium does not flow towards the pump against the operating flow direction of the heating circuit medium. On the other hand, the degassing device ensures that the heat pump circuit medium that has passed through does not spread in the operating flow direction of the heating circuit medium. Furthermore, it is particularly preferably provided that the heating circuit pump is designed to switch off automatically if the supply quantity of heating circuit medium falls below a predetermined level, i.e.In the event of the gas leak mentioned, not only is the entry of particularly flammable heat pump circuit medium into the heating circuit effectively prevented, but it is even guaranteed that the circulation of the heating circuit is automatically switched off completely.

[0008] Other advantageous developments of the heat pump system according to the invention emerge from the dependent patent claims.

[0009] For the sake of completeness, reference is made to document DE 10 2016 106 061 A1.

[0010] The heat pump system according to the invention, including its advantageous developments according to its dependent patent claims, is explained in more detail below with reference to the drawings of two exemplary embodiments.

[0011] It shows Figure 1 shows, largely schematically, the heat pump system according to the invention with the check valve and the degassing device; Figure 2 shows, in section, a first embodiment of the degassing device; and Figure 3 shows, in section, part of a second embodiment of the degassing device.

[0012] The heat pump system shown in the figures consists in a known manner of a heat exchanger 2 having a primary side 2.1 and a secondary side 2.2, a heat pump circuit 1 for a heat pump circuit medium flowing through the primary side 2.1 of the heat exchanger 2 and a heating circuit 3 for a heating circuit medium flowing through the secondary side 2.2 of the heat exchanger 2, wherein a heating circuit pump 4 is connected upstream of the secondary side 2.2 of the heat exchanger 2 in the operating flow direction of the heating circuit medium.

[0013] Furthermore, in a manner known per se, it is preferably provided that the heat pump circuit 1 comprises, in addition to the heat exchanger 2, a throttle device 9, a further heat exchanger 10, and a compressor 11. If the heat pump system is used to heat a building (heating mode), the heat exchanger 2 functions as a condenser, and the further heat exchanger 10 functions as an evaporator, to which heat is typically supplied via an environmental heat source such as air heat or geothermal energy. If, however, the heat pump system is used for cooling (which is also possible), the heat exchanger 2 is designed to operate as an evaporator.

[0014] Furthermore, when using the heat pump system in heating mode, it is provided in a manner known per se that the heating circuit 3 optionally comprises heat emission devices (for example radiators or underfloor heating) and / or heat storage devices (for example a hot water storage tank).

[0015] It is further provided that, firstly, a check valve 5 is provided downstream of the heating circuit pump 4 and upstream of the secondary side 2.2, as seen in the operating flow direction of the heating circuit medium, and is designed to close when the heating circuit medium flows opposite to the operating flow direction, and that, secondly, a degassing device 6 is connected downstream of the secondary side 2.2, as seen in the operating flow direction. It is essential for the heat pump system according to the invention that the degassing device 6 is designed to prevent the heating circuit medium from flowing in the operating flow direction once a predefined amount of gas (of heat pump circuit medium) has been reached in the heating circuit medium, wherein the degassing device 6 has a float 6.1.In procedural terms, it is provided that, once a predefined amount of gas from the heat pump circuit medium in the heating circuit medium has been reached, the check valve 5 closes, and the degassing device 6 prevents the heating circuit medium from flowing in the operating flow direction. As already explained above, these requirements ensure that, in the event of a leak in the heat exchanger 2, the heat pump circuit medium can only enter the heating circuit 3 to a limited extent.

[0016] It is further particularly preferred that a relief valve 12 is provided on the degassing device 6, via which the heat pump circuit medium can be discharged to the surroundings of the building in the event of a leak.

[0017] The term "predefined" used above means that the degassing device 6 is designed such that the flow is only stopped above a certain leakage rate. This means that leaks below this "predefined" amount are tolerated according to the invention or are separated via the vent 7, which will be explained below, since they do not yet pose any danger. However, a small leak over a longer period of time would naturally be "noticed" by the heat pump itself and would then lead to its shutdown.

[0018] In this case, it is particularly preferably provided that optionally the heat exchanger 2 and / or the degassing device 6 is / are arranged outside a building partially accommodating the heating circuit 3, ie according to the invention it is ensured that the heat pump circuit medium cannot enter the building in the first place and possibly cause damage there.

[0019] To further support this safety function, as already explained, it is particularly preferred that the heating circuit pump 4 is configured to automatically switch off or switch off automatically when the supply quantity of heating circuit medium (to the heating circuit pump 4) falls below a predetermined level. This means that the heating circuit pump 4 switches off as soon as there is no longer sufficient heating circuit medium at its pump inlet, i.e., there is a risk that the heating circuit pump will run "empty." This undershoot results from the action of the degassing device 6, described in more detail below, which ensures that the heating circuit medium can no longer circulate in the heating circuit 3 in the event of a leak in the heat exchanger 2.

[0020] With regard to the degassing device 6, it is particularly preferably provided (and the following explanations apply, unless stated otherwise, to all embodiments of the degassing devices according to the invention) that this is designed as a container with an inlet 6.2 and an outlet 6.3 for the heating circuit medium. It is further particularly preferably provided that the inlet 6.2 is arranged above the outlet 6.3 during normal operation of the heat pump system. Furthermore, it is particularly preferably provided that the outlet 6.3 is arranged at a lowest point 6.4 on the container. The container further preferably has a volume for receiving heating circuit medium of at least 1.5 liters, particularly preferably at least 2.5 liters, very particularly preferably at least 3.5 liters. It is further preferably provided that a flow velocity of the heating circuit medium at the transition from the inlet 6.2 to the tank by at least 50%, preferably 75%. It is particularly preferred that the flow velocity in the tank be at most 0.4 m / s, most preferably at most 0.3 m / s. This provision provides the significant advantage that any gaseous heat pump circuit medium present in the heating circuit medium is not entrained to the outlet 6.3, but can rise upwards in the tank and then be discharged.

[0021] To achieve the flow prevention, as already mentioned above, the degassing device 6 is provided with a float 6.1 which forms a plug in the event of a leak.

[0022] In the embodiment according to Figure 2 This float 6.1 is designed as an elongated plug tapered at its lower end. In the embodiment according to Figure 3the float 6.1, on the other hand, is designed as a sphere. What all embodiments have in common, of course, is that the float 6.1 has a lower density than the heating circuit medium and accordingly floats in it, provided the degassing device 6 is filled with it. If, on the other hand, the heating circuit medium has been forced out of the degassing device in the event of a leak from the heat pump circuit medium, the float 6.1 closes the outlet 6.3 mentioned above. Or, to put it in other words, it is particularly preferably provided that the float 6.1 is designed to float in the heating circuit medium below the predefined gas quantity (at the top of the container when the container is completely filled with heating circuit medium) and to close the outlet 6.3 above the predefined gas quantity.

[0023] For this purpose, it is particularly preferred that the float 6.1 be arranged above the lowest point 6.4 in the tank during normal operation of the heat pump system. Furthermore, it is preferably provided that the float 6.1 is mounted vertically displaceably within the tank during normal operation of the heat pump system.

[0024] Looking at it in more detail, it is particularly preferred - and this also applies to all embodiments of the degassing device 6 - that the above-mentioned container is formed from a cylindrical casing 6.5 closed on both sides with cover elements 6.6. Furthermore, a preferably tubular guide element 6.7 for the float 6.1 is particularly preferably arranged in the container. As shown in the Figures 2 and 3As shown, it is furthermore particularly preferred for the flow calming that the guide element 6.7 has flow openings 6.8 for the heating circuit medium, ie the heating circuit medium flows from the inlet 6.2 into an outer region of the container and from there through the flow openings 6.8 into an inner region of the container, where the float 6.1 is movably mounted and opens into the outlet 6.3.

[0025] Finally, it is preferably provided that a safety valve 8 is optionally arranged between the heat exchanger 2 and the degassing device 6 and / or that the degassing device 6 has a vent 7 (for rapid venting in the case of small gas quantities), wherein in addition a valve for manual venting can also be provided on the degassing device 6 - as shown.

[0026] The heat pump system according to the invention functions without leaks or leakage at the heat exchanger 2, i.e., during proper operation, as follows: The heating circuit medium coming from the heat exchanger 2 flows via the inlet 6.2 into the tank of the degassing device 6. This tank is filled with heating circuit medium, so that the float 6.1, guided by the guide element 6.7 provided with flow openings 6.8, floats at the top of the heating circuit medium. The outlet 6.3 is located at the lowest point 6.4 of the tank, through which the heating circuit medium leaves the degassing device 6 and flows toward, for example, the radiator.

[0027] If a significant leak now occurs at the heat exchanger 2, i.e. if, which is absolutely undesirable, in particular flammable heat pump circuit medium (for example propane) from the heat pump circuit 1, which is operated at a very high pressure, enters the heating circuit 3, which is operated at a significantly lower pressure, in a larger quantity, the heating circuit medium stored in the container of the degassing device 6 is pressed out of it, so that the float 6.1 reaches the bottom and then, due to the then high pressure in the container, tightly closes the outlet 6.3 until significant quantities of the heat pump circuit medium have been blown off via the relief valve 12, whereby the closure of the outlet 6.3, as described and even promoted by the suction of the heating circuit pump 4 itself, leads to the heating circuit pump 4 also ceasing its operation, ieThe entire heat pump system goes into complete malfunction, which is logical for this type of fault, whereby, since the relief valve 12 is designed to open outwards, it is ensured according to the invention that no flammable heat pump circuit medium can enter the building to be heated. List of reference symbols

[0028] 1 Heat pump circuit 2 Heat exchanger 2.1 Primary side 2.2 Secondary side 3 Heating circuit 4 Heating circuit pump 5 Check valve 6 Degassing device 6.1 Float 6.2 Inlet 6.3 Outlet 6.4 Lowest point on the tank 6.5 Shell 6.6 Cover element 6.7 Guide element 6.8 Flow opening 7 Vent 8 Safety valve 9 Throttle device 10 Heat exchanger 11 Compressor 12 Relief valve

Claims

1. A heat pump system, comprising a heat exchanger (2) having a primary side (2.1) and a secondary side (2.2), a heat pump circuit (1) for a heat pump circuit medium flowing through the primary side (2.1) of the heat exchanger (2), and a heating circuit (3) for a heating circuit medium flowing through the secondary side (2.2) of the heat exchanger (2), wherein a heating circuit pump (4) is connected upstream of the secondary side (2.2) of the heat exchanger (2) when viewed in the operating flow direction of the heating circuit medium, wherein when viewed in the operating flow direction of the heating circuit medium, a check valve (5) is provided which is connected downstream of the heating circuit pump (4) and upstream of the secondary side (2.2), and which is designed to close when there is a flow of heating circuit medium opposite the operating flow direction, wherein a degassing device (6) is connected downstream of the secondary side (2.2), characterized in that, when viewed in the operating flow direction, the degasing device (6) is designed to prevent a flow of the heating circuit medium in the operating flow direction from a predefined gas amount in the heating circuit medium, wherein the degassing device (6) has a floater (6.1).

2. The heat pump system according to Claim 1, characterized in that the degassing device (6) is designed as a container with an inlet (6.2) and with an outlet (6.3) for the heating circuit medium.

3. The heat pump system according to Claim 2, characterized in that the inlet (6.2) is arranged above the outlet (6.3) when the heat pump system is operating as intended, i.e. when the heating circuit medium is pumped through the heating circuit in the operating flow direction.

4. The heat pump system according to Claim 2 or 3, characterized in that the outlet (6.3) is arranged at a lowest point (6.4) on the container.

5. The heat pump system according to Claim 4, characterized in that the floater (6.1) is arranged above the lowest point (6.4) in the container during intended operation of the heat pump system, i.e. when the heating circuit medium is pumped through the heating circuit in the operating flow direction.

6. The heat pump system according to Claim 2, characterized in that the floater (6.1) is vertically displaceable within the container during intended operation of the heat pump system, i.e. when the heating circuit medium is pumped through the heating circuit in the operating flow direction.

7. The heat pump system according to Claim 2, characterized in that the floater (6.1) is designed to float on the heating circuit medium below the predefined gas amount, and to close the outlet (6.3) above the predefined gas amount.

8. The heat pump system according to one of Claims 1 to 7, characterized in that the heating circuit pump (4) is designed to switch off automatically in the case of a shortfall in a predetermined supply quantity of heating circuit medium.

9. Building with a heat pump system according to one of Claims 1 to 8, characterized in that the heat exchanger (2) and / or the degassing device (6) is or are selectively arranged outside a building partially receiving the heating circuit (3).

10. A method for operating a heat pump system according to one of Claims 1 to 9, characterized in that from a predefined gas amount of the heat pump circuit medium in the heating circuit medium, on the one hand, the check valve (5) closes and, on the other hand, the degassing device (6) prevents a flow of the heating circuit medium in the operating flow direction.

11. The method according to Claim 10, characterized in that the heating circuit pump (4) switches off automatically in the case of a shortfall in a predetermined supply quantity of heating circuit medium to the heating circuit pump (4).

12. The method according to Claim 10 or 11, wherein the heating circuit medium flows via an inlet (6.2) into a container of the degassing device (6), characterized in that a flow rate of the heating circuit medium is reduced by at least 50 % at the transition from the inlet (6.2) to the container.