Heat pump hydraulic unit and heat pump system

Abstract

A heat pump hydraulic unit (100) is provided with a first connection (101) for a heat pump return (RL), a second connection (102) for a heat pump supply (VL), a third connection (103) for a hot water return (RLW), a fourth connection (104) for a hot water supply (VLW), a fifth connection (105) for a supply of the first heating circuit (VLHK1), a sixth connection (106) for a return of the first heating circuit (RLHK1), a 4 / 3-way valve (130) with four connections (131 - 134), a first circulation pump (140) which is coupled to the second connection (102) and the 4 / 3-way valve, and a bypass valve (190) between the fifth and sixth connections (105, 106), and a first temperature sensor (182) between the circulation pump. (140) and the 4 / 3-way valve (130), and a second temperature sensor (181) at the sixth port (106).

Description

[0001] The present invention relates to a heat pump hydraulic unit and a heat pump system.

[0002] Heat pumps can be used to both produce hot water and heat a building. This typically requires a buffer storage tank for the hot water and a separate buffer storage tank for the building's heating system.

[0003] DE 10 2021 118 041 A1 describes a domestic technology device with a heat pump and a storage tank as well as a buffer storage tank.

[0004] It is an object of the present invention to provide a heat pump hydraulic unit and a heat pump system which has a smaller space requirement and can ensure a minimum water flow rate.

[0005] This problem is solved by a heat pump hydraulic module according to claim 1 and by a heat pump system according to claim 6.

[0006] The hydraulic unit can be connected to the heat pump's corresponding connections via the heat pump's flow and return lines. The circulation pump can be connected in series with the heat pump's flow line. The 4 / 3-way valve is connected to the circulation pump's outlet, a domestic hot water supply connection, and a supply connection of the first heating circuit. The 4 / 3-way valve can also be connected to a supply line of a second heating circuit. To prevent the minimum hot water flow rate from being undershot, the hydraulic unit has a bypass valve between the flow and return lines of the first heating circuit.

[0007] If it is detected that the water flow rate falls below a minimum value, then the bypass valve can be opened.

[0008] With the heat pump hydraulic unit according to an example, it can be ensured in a hydraulic unit with two heating circuits and a 4 / 3-way valve that a minimum water flow rate of the heat pump is present when two heating circuits are connected, without affecting the temperature control for one of the two heating circuits.

[0009] If the minimum water flow rate is exceeded again, the valve can be closed, but not completely. Specifically, it can remain open enough to allow a minimal flow of water through the valve. This flow rate can be significantly smaller than the flow rate supplied to the first heating circuit. This has the advantage of reducing the impact on the return temperature.

[0010] Using the hydraulic module shown in the example, a heat pump system can be designed without the need for a buffer storage tank. This is more cost-effective to purchase and allows for installation of the system with a smaller footprint.

[0011] By installing a bypass valve between the flow and return lines of the first heating circuit and monitoring the flow rate, it can be ensured that the heat pump system always operates with a minimum flow rate. This is achieved through appropriate control of the bypass valve, which opens when the minimum flow rate is undershot.

[0012] By installing temperature sensors in the flow and return pipes of the first heating circuit, it is possible to detect when the first heating circuit is no longer drawing heat. Once this is detected, the temperature can be adjusted to the target temperature of the second heating circuit.

[0013] The two temperature sensors detect a temperature difference between the flow and return of the first heating circuit HK1.

[0014] Optionally, a temperature sensor can be installed in the flow and return lines of the first heating circuit. The bypass valve can then be controlled according to the temperatures measured there.

[0015] The heat pump hydraulic unit can, for example, have two operating modes. A first operating mode is activated when the water flow rate is above a threshold and the bypass valve is closed. The second operating mode is activated when the water flow rate falls below a threshold, where the threshold represents a minimum flow rate required, for example, by the heat pump. In the second operating mode, the bypass valve is opened, allowing water to flow through.

[0016] In the second operating mode, the first and second temperature sensors can measure their respective temperatures. The bypass valve is controlled in this mode based on the water flow rate. If the temperatures measured by the two sensors match, this indicates that the first heating circuit has no heating demand. In this case, the hot water supply temperature can be reduced. This is particularly useful if there is a second heating circuit with a lower setpoint temperature than the first. Since the first heating circuit no longer requires heat, the temperature supplied by the heat pump can be reduced. Specifically, it can then be adjusted to the setpoint temperature for the second heating circuit. This is advantageous because it allows the heat pump to operate more efficiently.

[0017] If the flow temperature and the return temperature are the same, it can be determined that the first heating circuit has no need for hot water and the water temperature supplied by the heat pump can be lowered to the level of the second heating circuit.

[0018] According to one aspect, the bypass valve, after being opened in the second operating mode and then reactivated in the first operating mode, cannot be completely closed. This incomplete closure of the valve can reduce the risk of it becoming stuck.

[0019] By providing a return temperature sensor that is always exposed to flow, it is possible to avoid the control of the circulation pump with regard to the temperature difference in the first heating circuit leading to undesirable temperatures when the first heating circuit can no longer release the heat.

[0020] The hydraulic unit ensures a minimum water flow rate and allows the heat pump's water temperature to be lowered when the first heating circuit no longer requires heat, so that the water temperature can be adjusted to the target temperature of the second heating circuit. The target temperature of the second heating circuit is lower than the target temperature of the first heating circuit.

[0021] If a second heating circuit is present, then a second circulation pump can optionally be provided for the second heating circuit.

[0022] Several operating modes can be implemented by appropriately controlling the 4 / 3-way valve. Specifically, the following modes are possible: domestic hot water preparation, heating of the first heating circuit, heating of the first heating circuit including bypass through the bypass, heating with a closed first heating circuit and bypass through the bypass, defrosting with an open first heating circuit, another defrosting with one heating circuit and bypass through the bypass, another defrosting with bypass via the bypass, a fourth defrosting with one heating circuit and bypass in the hot water storage tank, and a fifth defrosting with bypass in the hot water storage tank and energy absorption via the hot water storage tank.

[0023] The heat pump system can include a heat pump, a hydraulic unit, and a hot water storage tank. The hydraulic unit further comprises a housing, a heat pump flow, a heat pump return, a hot water return, a hot water flow, and at least one heating circuit flow and return for a heating circuit. The hydraulic unit can be connected to a hot water storage tank. The flow and return connections are directly connected to the heating circuit; that is, no buffer tank is used in between. This is advantageous because it saves the space required for a buffer tank.

[0024] The described hydraulic unit ensures the proper operation of the heat pump system with a minimum water flow rate. In particular, it prevents a situation where the 4 / 3-way valve splits the heat pump's water flow, directing part to the first heating circuit and another part to the bypass loop of the second heating circuit. For example, if the heat demand of the first heating circuit is low and the temperature difference between the two circuits is high, the minimum hot water flow rate of the heat pump may be undershot, even though the circulation pump is running at maximum speed. This situation can be effectively avoided by the hydraulic unit described above.

[0025] Furthermore, a situation can be avoided in which heating circuit 1 has no heat demand and all consumers of the first heating circuit (e.g., radiators, underfloor heating circuits) are closed, so that heating water flows from the heat pump's flow pipe to the bypass section of the second heating circuit. The heat pump provides the heating water at a temperature level corresponding to the setpoint of the first heating circuit. If this setpoint is higher than the setpoint of the second heating circuit, the hot water flows mix in the bypass section, resulting in energy loss and inefficient system operation.

[0026] The hydraulic unit of a heat pump is a central component of the system, establishing a connection between the heat pump and the building's heating or cooling system. The hydraulic unit's function is to transfer the heat (or cold) generated by the heat pump to the heating or cooling system (e.g., underfloor heating, radiators, ventilation system).

[0027] The hydraulic unit can include a circulation pump for circulating the heating water in the system and a three-way valve. The valve regulates the water temperature by mixing different water flows (e.g., warm water from the heat pump and cooler return water).

[0028] According to one aspect, a minimum volume flow can be ensured in a defrosting operating mode using the bypass valve.

[0029] Further embodiments of the invention are the subject of the dependent claims.

[0030] The advantages and embodiments of the invention are explained in more detail below with reference to the drawing. Fig. 1 shows a schematic representation of a heat pump system, and Fig. 2 shows a further schematic representation of a hydraulic unit and a schematic representation of a four-way valve in the respective operating mode.

[0031] Fig. 1 shows a schematic representation of a heat pump system. Fig. 1 A heat pump system or a building technology unit 1 is shown, which has a heat pump WP, a hydraulic unit 100 and a hot water storage tank 200.

[0032] The hydraulic unit of a heat pump is a central component of the system, establishing a connection between the heat pump and the building's heating or cooling system. The hydraulic unit's function is to transfer the heat (or cold) generated by the heat pump to the heating or cooling system (e.g., underfloor heating, radiators, ventilation system).

[0033] The hydraulic unit 100 has a first and second connection 101, 102, for the return RL and flow VL of the heat pump. Furthermore, the hydraulic unit 100 has a third and fourth connection 103, 104, which are configured as the return RLW and flow VLW for domestic hot water preparation (e.g., via the hot water storage tank 200). Additionally, the hydraulic unit 100 can have a fifth and sixth connection 105, 106, for the return RLHK1 of a first heating circuit HK1 and the flow VLHK1 of a first heating circuit HK1.

[0034] Optionally, the hydraulic unit 100 can have a seventh and eighth connection 107, 108 for a flow VLHK2 and a return RLHK2 of a second heating circuit HK2.

[0035] The hydraulic unit 100 has a circulation pump 140 connected to the second port 102, and optionally an electric heating unit 120 connected in series with the circulation pump 140. The circulation pump 140 serves to circulate the heating water within the system. Furthermore, the hydraulic unit 100 has a 4 / 3-way valve 130. The 4 / 3-way valve 130 has four ports 131–134. By controlling the 4 / 3-way valve 130, the respective ports 131–134 can be connected to each other. The valve 130 can be used to regulate the water temperature by mixing different water flows.

[0036] Optionally, a safety group 150 can be provided at the output of the heating unit 120.

[0037] An optional bypass section 160 can be provided. The heat pump typically requires a minimum flow rate. The bypass section 160 can serve to provide this minimum flow rate for the heat pump. The bypass section 160 can be connected to the first connection 101, allowing water to flow through the bypass section 160 to connection 101 and thus to the heat pump.

[0038] Furthermore, a second heating circuit HK2 with a heating circuit flow 107 and a heating circuit return 108 can optionally be provided. If a second heating circuit HK2 is provided, then a second circulation pump 170 can optionally be provided.

[0039] The heat pump system 1 also has a buffer storage tank 200 for hot water, which is coupled to the third and fourth connections 103, 104, which represent the hot water return and the hot water supply.

[0040] Fig. 2Figure 1 shows another schematic representation of a hydraulic unit and a schematic representation of a 4 / 3-way valve in its respective operating mode. Fig. 2 A heating operation with an overflow via an overflow path of 160 is shown. In the example of Fig. 2 The four-way valve 130 is switched such that ports 131, 132 and 133 are open.

[0041] In addition to the components of the hydraulic unit of Fig. 1 The hydraulic unit of Fig. 2A bypass valve 190 and two temperature sensors 181, 182 are installed. The bypass valve 190 is located between the flow of the first heating circuit VLHK1 and the return RLHK1 (i.e., between the fifth and sixth connections 105, 106). The first temperature sensor 182 is located in the flow of the first heating circuit VLHK1, and the second temperature sensor 181 is located in the return of the first heating circuit RLHK1. The two temperature sensors 181, 182 thus measure the temperatures in the flow and return of the first heating circuit HK1 and can therefore determine the temperature difference.

[0042] A first operating mode is activated when the measured water flow rate of the heat pump is above a threshold value (minimum water flow rate). A second operating mode is activated when the water flow rate falls below the minimum water flow rate, in which case the bypass valve 190 is opened.

[0043] The temperature sensor 182 in the flow line of the first heating circuit HK1 can be installed before or after the 4 / 3-way valve. The second temperature sensor 181 is located in the return line of the first heating circuit HK1.

[0044] The bypass valve 190 is controlled to prevent the minimum water flow rate of the heat pump from being undershot. If the minimum water flow rate of the heat pump is undershot, the bypass valve 190 opens until the flow rate exceeds the minimum value. If the minimum flow rate of the heat pump is exceeded, the bypass valve 190 can be closed again. Optionally, the bypass valve 190 can remain partially open, allowing a minimal water flow through it. This requires that the 4 / 3-way valve is not fully open towards the second heating circuit (HK2), but is still partially open towards the first heating circuit (HK1).

[0045] The flow rate through the partially closed bypass valve 190 is significantly lower than the flow rate flowing to the first heating circuit HK1, so its influence on the return temperature is minimal. When all consumers in the first heating circuit HK1 are closed, only water from the supply line flows to the return temperature sensor, and the supply and return temperatures are equal. In this case, the control system can detect that the first heating circuit HK1 has no heat demand, and the water temperature generated by the heat pump can be reduced to the level of the second heating circuit HK2.

[0046] By providing a bypass valve and the corresponding control system, a minimum flow rate can be ensured regardless of the behavior of the heating circuits. In particular, it can detect when heating circuit 1 no longer has a heat demand and lower the system temperature to increase system efficiency. Reference symbol list

[0047] 1. Domestic service unit 100. Hydraulic unit 101. Heat pump return 102. Heat pump flow 103. Third connection 104. Fourth connection 105. Heating circuit flow 106. Sixth connection 107. Seventh connection 108. Eighth connection 120. Heating unit 130. Four-way valve 131. First valve connection 132. Second valve connection 133. Third valve connection 134. Fourth valve connection 140. First circulation pump 150. Safety group 160. Bypass 170. Second circulation pump 181. Second temperature sensor 182. First temperature sensor 200. Hot water storage tank RL. Heat pump return RLW return VL. Heat pump flow VLW flow WP heat pump

Claims

1. Heat pump hydraulic unit (100), with a first connection (101) for a heat pump return (RL), a second connection (102) for a heat pump supply (VL), a third connection (103) for a hot water return (RLW), a fourth connection (104) for a hot water supply (VLW), a fifth connection (105) for a supply of the first heating circuit (VLHK1), a sixth connection (106) for a return of the first heating circuit (RLHK1), a 4 / 3-way valve (130) with four connections (131 - 134), a first circulation pump (140) which is coupled to the second connection (102) and the 4 / 3-way valve, and a bypass valve (190) between the fifth and sixth connections (105, 106), a first temperature sensor (182) between the circulation pump (140) and the 4 / 3-way valve (130), and a second temperature sensor (181) at the sixth port (106).

2. Heat pump hydraulic unit (100) according to claim 1, wherein a first operating mode is activated when a water flow rate at the heat pump return or heat pump supply at the first and / or second connection (101, 102) is above a threshold value, wherein the bypass valve (190) is closed, and wherein a second operating mode is activated when the water flow rate is below the threshold value, wherein the threshold value represents a minimum flow rate, wherein the bypass valve (190) is open in the second operating mode.

3. Heat pump hydraulic unit (100) according to claim 2, wherein the bypass valve (190) remains partially open when the detected volume flow is again above the minimum volume flow and the first operating mode is activated.

4. Heat pump hydraulic unit (100) according to claim 2 or 3, with a seventh and eighth connection (107, 108) for a second heating circuit (HK2), wherein in the second operating mode the first and second temperature sensors (182, 181) detect a first and second temperature, wherein, if the temperature measured by the first temperature sensor (182) corresponds to the temperature detected by the second temperature sensor (181), then the flow temperature of the heat pump is reduced to a value which is adapted to the second heating circuit (HK2).

5. Heat pump hydraulic unit according to one of claims 1 to 4, wherein if the bypass valve (190) is at least partially open and if the temperature measured by the first temperature sensor (182) corresponds to the temperature detected by the second temperature sensor (181), then it is detected that the first heating circuit (HK1) is not absorbing any heat.

6. Method for controlling a heat pump hydraulic unit according to any one of claims 1 to 5, comprising the steps of: detecting a volume flow rate of a heat pump, opening the bypass valve when the volume flow rate falls below a threshold value, detecting a return temperature at the sixth connection, namely in the return of the first heating circuit, detecting a supply temperature at the supply of the first heating circuit, and reducing the supply temperature of the heat pump when the return temperature of the first heating circuit substantially corresponds to the supply temperature of the first heating circuit, or increasing the supply temperature of the heat pump when the return temperature falls below the supply temperature by a threshold value.

7. Heat pump system, comprising a heat pump hydraulic unit (100) according to one of claims 1 to 5, a first heating circuit (HK1), a second heating circuit (HK2), a heat pump (WP), and a hot water buffer storage tank (200).

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