HEATING AND / OR HOT WATER PREPARATION SYSTEM

Description

[0001] The present invention relates to a heating and / or hot water preparation system which is designed to produce heating water and / or hot water.

[0002] It is common practice to heat hot water and heating water using different heaters. Such heaters include heat pumps, for example, but direct heating systems are also conceivable. Using the same heater or heat generator to generate hot water and heating water is possible, but in this case, hot water and heating energy are provided alternatively. This means that while hot water is being generated, the heating water is not being heated, and the rooms heated by the heater are at risk of cooling down.

[0003] The difficulty of heating domestic hot water and heating water simultaneously is primarily due to the fact that the generated heating water and the generated domestic hot water are provided at different temperatures. A typical flow temperature for heating water, for example, is in the range of 50 to 60°C, although modern passive houses in particular allow for significantly lower heating flow temperatures. The desired temperature for domestic hot water, however, can be significantly higher.

[0004] Parallel operation of heating water and hot water generation in existing systems would result in either an excessively high heating flow temperature, resulting in high heat loss, or a low hot water temperature. As mentioned above, the alternate provision of hot water and heating energy ensures that, for example, living spaces cannot be heated while hot water is being generated, and the temperature can therefore drop to an uncomfortably high level.

[0005] Common solutions involve providing large buffer tanks to ensure sufficient heating water or hot water is available at all times. Unfortunately, such large buffer tanks require a lot of space. The use of separate generators for hot water and heating water also requires a lot of space.

[0006] WO 2007 / 004962 A1 discloses a heating system comprising a heat pump for simultaneously or separately heating a hot water circuit and a heating circuit. An adjustable switching valve is arranged in a section of a heating circuit, by means of which partial quantities of the medium are directed toward the heating circuit and / or the hot water circuit.

[0007] US 4,955,207 A1 discloses a combined hot water heater-cooling assembly with a cooling assembly coupled to a hot water tank via a heat pipe. The heat-emitting end of the heat pipe is located near the bottom of the hot water tank.

[0008] Against this background, it was an object of the present invention to provide hot water and heating water without the known disadvantages of the prior art with a single heating device, in particular a heat pump.

[0009] According to one aspect of the invention, a heating and / or hot water preparation system according to claim 1 is provided. The system comprises a heating circuit and a heat pump circuit, wherein the heat pump circuit has a heat exchanger device configured to transfer heat from the heat pump circuit to the heating circuit. The heating circuit comprises a heating circuit with a heating flow and a heating post-flow, a hot water circuit with a hot water flow and a hot water post-flow, and a controllable mixer, wherein the mixer is configured to divide a volume flow through the heating circuit at least between the heating flow and the hot water flow. The heat exchanger device has a first heat exchanger and, in series therewith, a second heat exchanger.The second heat exchanger is designed to transfer heat to the heating circuit upstream of the mixer and the first heat exchanger is designed to transfer heat to the hot water flow downstream of the mixer.

[0010] Because the heat exchanger system features two heat exchangers connected in series, the hot water supply can be heated to a higher temperature than the heating circuit, which will be explained in more detail below. It should be noted that the heat exchangers are connected in series in the direction of refrigerant flow, i.e., on the heat pump circuit side, but not necessarily on the heating circuit side. This allows the hot water circuit to generate hot water at a higher temperature than required for the heating supply. This ensures energy-optimized operation of the heating and / or hot water system.

[0011] In this context, "in series" specifically means that the same refrigerant flows through the first heat exchanger and the second heat exchanger at consecutive times. It is irrelevant whether other components of the heat pump circuit are located between the first heat exchanger and the second heat exchanger in the direction of refrigerant flow, as long as the sequential, i.e., not parallel, flow through the first and second heat exchangers is maintained. In other words, the "in series" arrangement can be distinguished from a parallel connection of the first heat exchanger and the second heat exchanger.

[0012] Furthermore, the adjustable mixer allows for simultaneous operation of the heating system and the provision of hot water. Compared to diverter valves of conventional solutions, this prevents unwanted drops in room temperatures when hot water is being provided. The clever control of the mixer makes it possible to optimally distribute the heating output generated by the heat pump circuit between the hot water generation and the heating circuit.

[0013] A suitable refrigerant preferably flows through the heat pump circuit. All types of heat pumps, such as air or brine heat pumps, can be advantageously used.

[0014] The first heat exchanger is designed as a desuperheater, and the second heat exchanger is designed as a condenser. Accordingly, the gaseous refrigerant flowing through the heat pump circuit through the heat exchanger device is cooled in the first heat exchanger without, however, significantly condensing, while the phase transition to the liquid phase takes place essentially in the second heat exchanger.

[0015] For example, the temperature of the refrigerant in the desuperheater can be reduced from 90°C (30°C-150°C) to 57°C (20°C-150°C), while the refrigerant in the condenser arranged in series is then cooled from 57°C (20°C-150°C) to 49°C (15°C-80°C) and liquefied in the process. The values ​​in parentheses indicate the temperature ranges typically expected at the relevant locations, depending on the selected refrigerant. At the same time, the water in the heating circuit can be heated by the condenser from, for example, 47°C (10°C-80°C) to, for example, 55°C (15°C-85°C), thus reaching the desired flow temperature. Downstream of the mixer, the hot water flow can then be further heated to, for example, 75°C (15°C-95°C). Of course, the numerical values ​​are to be understood as examples in order to clarify the functional principle of the invention.

[0016] According to the invention, the desuperheater is designed as a heat pipe, thermosiphon and / or heat pipe between the heat pump circuit and the hot water circuit.

[0017] A particular advantage of the heat pipe, thermosiphon, and / or heat pipe design is that heat transfer only occurs as long as the temperature level in the hot water circuit does not exceed a certain value, which is determined, for example, by the temperature of the refrigerant in the desuperheater and the desuperheater's design. In this case, the desuperheater is essentially self-limiting. This prevents boiling and potential damage to the entire system, even when no fluid is flowing in the hot water circuit.

[0018] Particularly preferably, the desuperheater is designed as a heat pipe. The circulation of a refrigerant in the heat pipe occurs due to gravity and not, for example, due to capillary effects as in a heat pipe. The design of the heat transfer through the heat pipe can thus be influenced by the installation position.

[0019] The pressure loss across the first heat exchanger differs from the pressure loss across the second heat exchanger. Pressure losses are associated with performance losses and are therefore rather undesirable. However, heat exchangers with high pressure losses, such as plate heat exchangers, are particularly advantageous for the condenser due to their high heat transfer performance. From an efficiency perspective, it has proven particularly advantageous to configure the first heat exchanger with a lower pressure loss than the second heat exchanger.

[0020] In one embodiment, the hot water circuit is arranged to heat a hot water storage tank to a desired temperature, wherein the mixer is designed to regulate the volume flow, in particular through the hot water circuit, such that the temperature in the hot water storage tank follows the desired value.

[0021] This ensures that sufficient hot water at the desired temperature is available in the hot water tank at all times without the temperature of the fluid in the heating circuit falling, since hot water is generated and the heating circuit is supplied at the same time.

[0022] In one embodiment, a circulation pump is arranged in the heating circuit. The circulation pump ensures that the heating circuit fluid, in particular water, flows through the heating circuit, i.e., the heating circuit and / or the hot water circuit.

[0023] In one embodiment, a direct heating system is arranged downstream of the first heat exchanger in the hot water supply. In some cases, even the series connection of the first heat exchanger and the second heat exchanger may not transfer sufficient energy to the hot water supply, for example, in the case of air-to-water heat pumps at very cold outside temperatures, so that the temperature of the hot water supply does not reach the required value. In this case, this temperature difference can be compensated for by the direct heating system.

[0024] The direct heating can, for example, be designed as an electric direct heating system, although other designs are also possible.

[0025] In one embodiment, a bypass line for bypassing a refrigerant circulating through the heat pump circuit is arranged past the first heat exchanger. The bypass line prevents further energy from being introduced into the hot water circuit during pure heating operation, i.e., when only a very low or no flow passes through the hot water circuit, thereby preventing the medium in the hot water circuit from boiling. Preferably, the bypass line is controllable by a controller of the heating and / or hot water system, with the controller preferably controlling the bypass line together with or depending on the position of the mixer.

[0026] In one embodiment, the heating and / or hot water preparation system can be operated in a pure heating mode, a pure hot water mode and a parallel operation of heating mode and hot water mode.

[0027] In one embodiment, a minimum volume flow through the hot water circuit is maintained during heating operation, wherein the minimum volume flow is dimensioned such that boiling in the hot water circuit is prevented.

[0028] Accordingly, in this embodiment, alternatively or in addition to the bypass line in the heat pump circuit, a suitable design of the hot water circuit is preferably provided, which ensures a certain minimum circulation through the hot water circuit even in pure heating operation. This can also reduce the risk of boiling in the hot water circuit.

[0029] In one embodiment, the heat pump circuit has a switching valve, wherein the switching valve is arranged such that a flow direction of a refrigerant flowing through the heat pump circuit remains the same when the switching valve is switched in the first heat exchanger and is reversed in the second heat exchanger.

[0030] It is known that during cycle reversal, when the evaporator is defrosted, an undesirable cooling of the first heat exchanger can occur. This risk is averted by the particularly clever arrangement of the first heat exchanger in the heat pump circuit: the cycle reversal only leads to a cooling of the second heat exchanger, while the first heat exchanger remains able to transfer heat from the heat pump circuit. This makes it possible for cycle reversal and cooling mode to simultaneously produce hot water while cooling the room. The energy used to cool the room is transferred to the hot water tank.

[0031] Preferably, the arrangement is realized in that the first heat exchanger and the second heat exchanger are arranged on different sides of the switching valve.

[0032] In a further aspect, the invention relates to a method for controlling a heating and / or hot water preparation system according to the invention, wherein the method comprises adjusting a position of a mixer between the heating circuit and the hot water circuit of a heating circuit as a function of a temperature of a hot water storage tank.

[0033] This ensures that the heating required for both the heating circuit and the hot water circuit is optimally selected so that the heating device, in particular a heat pump, which provides the energy to heat the heating circuit, can be operated with optimal power settings.

[0034] Further advantages and advantageous embodiments are illustrated below with reference to the attached figures. Herein: Fig. 1 schematically and exemplarily an embodiment of a heating and / or hot water preparation system in parallel operation, Fig. 2 schematically and exemplarily the embodiment of the Fig. 1 in pure heating mode, Fig. 3 schematically and exemplarily the embodiment of the Fig. 1 in pure hot water operation, Fig. 4 schematically and exemplarily another embodiment with bypass line in the hot water circuit, Fig. 5 schematically and exemplarily another embodiment of a heating and / or hot water preparation system, Fig. 6 schematically and exemplarily the embodiment of the Fig. 5 in pure heating mode, Fig. 7 schematically and exemplarily the embodiment of the Fig. 5 in pure hot water operation, Fig. 8 schematically and exemplarily another embodiment of a heating and / or hot water preparation system, Fig. 9 schematically and exemplarily the embodiment of the Fig. 8 in defrosting mode, Fig. 10 schematically and exemplarily shows another embodiment of the heating and hot water circuit, Fig. 11 schematically and exemplarily shows another embodiment of the heating and hot water circuit and Fig. 12 schematically and exemplarily shows another embodiment of a bypass.

[0035] Fig. 1 shows schematically and exemplarily an embodiment of a heating and / or hot water preparation system 100. The heating and / or hot water preparation system 100 comprises a heating circuit 20 and a heat pump circuit 30.

[0036] The heating circuit 20 is designed to provide heating water and hot water in parallel and, for this purpose, includes a heating circuit 22 with a heating flow 23 and a heating outlet 24, as well as a hot water circuit 26 with a hot water flow 27 and a hot water outlet 28. For example, a system of radiators through which heated water flows is arranged between the heating flow 23 and the heating outlet 24. Similarly, a hot water storage tank is arranged between the hot water flow 27 and the hot water outlet 28, with the water within the hot water storage tank being heated by the water flowing through the hot water circuit 26.

[0037] A circulation pump 12 is arranged in the heating circuit 20, which circulates the water or other fluid in the heating circuit 20. The division between the heating circuit 22 and the hot water circuit 26 is made possible by an adjustable mixer 13. The adjustable mixer 13 preferably has various positions, ranging from pure heating operation, i.e., complete flow in the heating circuit 22, to pure hot water operation, i.e., complete flow in the hot water circuit 26, with intermediate stages that can be finely adjusted as required. Furthermore, there is an inverter cooling system 10, including a cooling valve 11, provided for cooling the power electronics. This inverter cooling system discharges the required cooling power directly into the heating circuit 20 as needed, thus making it usable.Finally, a direct heating system 14, for example an electric direct heating system, is arranged in the hot water flow 27, which ensures, if necessary, a necessary reheating of the hot water flow 27 to the desired temperature, for example at very low outside temperatures.

[0038] Particularly advantageously, the mixer 13 of the heating and / or hot water preparation system 100 is controlled in such a way that the temperature of the hot water tank (not shown) through which the hot water circuit 26 flows is taken into account. Furthermore, the temperature of the heating flow 23 is preferably also taken into account.

[0039] The heat pump circuit 30 is described in more detail below. The heat pump circuit 30 is an example of a suitable heating device; similarly designed versions known to those skilled in the art, for example, by omitting or replacing one or more components, are also conceivable.

[0040] The heat pump circuit 30 comprises a compressor 1, which is configured to compress refrigerant circulating in the heat pump circuit 30. A switching valve 2, which is designed, for example, as a 2-4 way valve, determines the direction of circulation of the coolant in the heat pump circuit 30 through its position. For example, one circulation direction is suitable for heating operation—which is primarily used—while the reverse direction is specifically designed for defrosting an external heat exchanger, for example, an evaporator 9.

[0041] The heat pump circuit 30 also contains a heat exchanger device 3, which represents an internal heat exchanger, a collector 4, a filter dryer 5, a recuperator 6, a defrost coil 7, and an expansion valve 8. The components have the meanings customary in the field of heat pumps or refrigerant circuits and are familiar to those skilled in the art. Of course, the precise configuration, for example, with defrost coil 7 and recuperator 6, is merely a suitable configuration of the heat pump circuit 30, although other designs are also possible. The example also schematically shows an air / water heat exchanger as the evaporator 9, although the invention is not limited to this form of heat pump.

[0042] The heat exchanger device 3 comprises a first heat exchanger 3a and a second heat exchanger 3b connected in series. The first heat exchanger 3a, which is preferably designed as a desuperheater, is configured to transfer heat to the hot water supply 27. The medium flowing in the hot water supply 27 has already been preheated by the energy transfer of the second heat exchanger 3b, which corresponds, for example, to the known condenser. This makes it possible to raise the hot water supply 27 to a higher temperature than the heating supply 23.

[0043] The refrigerant flowing through the heat pump circuit 30 therefore releases its energy partly in the first heat exchanger 3a and partly in the second heat exchanger 3b. Because the temperature upon entering the first heat exchanger 3a is higher than upon entering the second heat exchanger 3b, a higher temperature is also possible on the heating circuit 20 side after passing through the first heat exchanger 3a.

[0044] The change in the temperature of the refrigerant as it flows through the heat exchanger device 3 is almost identical to the case of a conventional, one-piece heat exchanger. For example, in both cases, the conventional and the inventive heat exchanger, the refrigerant is cooled from 90°C to 49°C at a pressure of approximately 21 bar. By dividing the system into a first heat exchanger 3a and a second heat exchanger 3b, the desired temperature of the heating flow of, for example, 55°C can be achieved with, for example, 26 kW of available power for heating, while simultaneously allowing an even higher temperature level, for example, approximately 75°C, for the hot water flow 27.

[0045] The following control cases are conceivable in this embodiment not according to the invention, with a first heat exchanger 3a designed as a desuperheater.

[0046] Case A1: Heating with hot gas <100°C: In pure heating operation, the heating return 24 enters the second heat exchanger 3b, designed as a condenser, is heated, and is returned by the circulation pump 12 via the mixer 13 completely "to the left" as the heating flow 23 to the heating system. No water or medium is fed via the mixer 13 to the hot water tank via the desuperheater 3a. Case A1 or A2 are shown schematically in Fig. 2 shown, with lines in which there is no flow shown with dashed lines.

[0047] Case A2: Heating with hot gas > 100°C: In pure heating operation, the heating return 24 enters the second heat exchanger 3b, designed as a condenser, is heated, and then pumped by the circulation pump 12 to the mixer 13. There, the majority of the water, for example, is directed "to the left" as the heating flow 23 to the heating system. The other part of the water is directed "to the right" via the desuperheater 3a, so that the water does not boil there, and then through the water storage tank. Alternatively or additionally, a bypass line can be provided for this case.

[0048] Case B: Hot water. In pure hot water operation, the hot water return 28 enters the condenser 3b, is heated, and is directed completely "to the right" by the circulation pump 12 via the mixer 13 and the desuperheater 3a. After absorbing heat at the desuperheater 3a, the hot water flow 27 is directed to the hot water tank. In this case, no water is directed to the heater via the mixer 13. Case B is schematically shown in Fig. 3 shown.

[0049] Case C: Heating and hot water. In parallel operation, the combined return flow from heating 24 and hot water 28 enters the condenser 3b, is heated, and then pumped by the circulation pump 12 to the mixer 13. There, part of the water is directed "to the left" to the heating system as heating flow 23. The other part of the water is directed "to the right" for further heat absorption via the desuperheater 3a. After heat absorption at the desuperheater 3a, the hot water flow 27 is directed to the hot water tank. Case C corresponds to the Fig. 1 schematically shown parallel operation.

[0050] In addition to the possibility of constant and demand-based provision of hot water and heating output, there is the advantage of a constant hot water temperature in the storage tank, utilization of the high hot gas temperatures after refrigerant compression, which are above the refrigerant condensation temperature, and a small / compact installation space.

[0051] Not shown in the schematic example is the Fig. 1 a bypass line for bypassing refrigerant past the first heat exchanger 3a. In the case where, for example, pure heating operation is present, ie, the mixer 13 regulates the flow through the heating circuit 20 exclusively or almost exclusively through the heating circuit 22, boiling may occur in the hot water flow 27 if further energy is transferred to the hot water flow 27 through the first heat exchanger 3a. This further energy transfer can then be avoided by routing the refrigerant past the first heat exchanger 3a.

[0052] An alternative is the Fig. 4 schematically shown hot water bypass 16 in the hot water circuit 26. Here, the hot water bypass 16 ensures that even when no energy is to be introduced into the hot water tank, a flow through the hot water circuit 26 is possible.

[0053] Fig. 5 shows schematically and exemplarily a further embodiment of a heating and / or hot water preparation system 100. The embodiment of the Fig. 2 differs from the embodiment of the Fig. 1 in the design of the first heat exchanger 3a as heat pipe 15.

[0054] Instead of a heat pipe 15, a thermosiphon or a heat pipe can be used, or in addition. When using a heat pipe 15, the provision of a bypass line is unnecessary, since the heat pipe 15 is self-limiting and no energy transfer occurs if the temperature in the hot water flow 27 is too high, especially if it is in a potentially critical range.

[0055] In Fig. 5 The direct heating 14 is also arranged at a different location, namely in the heating circuit 20 in front of the mixer 13. The arrangement of the direct heating can be the same in the example of the Fig. 1 used or as in the example of Fig. 1 Combinations of both designs, ie with more than one direct heating system, are also possible.

[0056] Comparable to Fig. 2 and 3 show Fig. 6 and 7 schematically a pure heating operation or a pure hot water operation, while Fig. 5 illustrates parallel operation.

[0057] Fig. 8 shows schematically and exemplarily a further embodiment of a heating and / or hot water preparation system 100. Compared to the embodiment of the Fig. 1 the position of the switching valve 2 is different with respect to the first heat exchanger 3a, or on the other side with respect to the recuperator 6 or the compressor 1.

[0058] In Fig. 8 a heating and / or hot water operation is shown, that is, the switching valve 2 is switched in such a way that a refrigerant flow flows through the heat pump circuit 30 in the sequence compressor 1, first heat exchanger 3a, second heat exchanger 3b, wherein the switching valve 2 is arranged between the first heat exchanger 3a and the second heat exchanger 3b. In this operation, the function of executing the Fig. 8 comparable to the function of executing the Fig. 1 .

[0059] In pure heating mode, the mixer 13 on the hot water circuit 26 side is closed. The cooling valve 11 and the expansion valve 8 are controlled. In combined heating and hot water mode, both the mixer 13, the cooling valve 11, and the expansion valve 8 are controlled, while in pure hot water mode, the mixer 13 is open.

[0060] Further in Fig. 8 An air inlet 40 from outside and an air outlet 42 to the outside are shown, with the air flow being guided over the evaporator 9. A safety outlet 44 to the outside is also shown penetrating a heat pump system boundary 46, which is drawn with dashed lines.

[0061] The execution of the Fig. 8 can also be compared with the statements of the Fig. 1-7 be combined, which means in particular that a direct heating 14, a heat pipe 15 or a hot water bypass 16 can be provided, for example.

[0062] Fig. 9 shows schematically and exemplarily the embodiment of the Fig. 8 in defrosting or cooling mode, i.e. after reversing the reversing valve 2.

[0063] It can be seen that not only the direction of the refrigerant but also the order of the components of the heat pump circuit 30 through which the refrigerant flows has changed.

[0064] Thus, the refrigerant now flows through the second heat exchanger 3b upstream of the compressor 1, i.e., on the low-pressure side, while the refrigerant flows through the first heat exchanger 3a downstream of the compressor 1, thus still on the high-pressure side. The flow direction through the second heat exchanger 3b has reversed, while it remains the same through the first heat exchanger 3a. The risk of undesired cooling or subcooling of the first heat exchanger 3a during defrosting of the evaporator 9 is therefore reduced.

[0065] In addition, Fig. 9 The hot water bypass 16 is shown. This ensures independent hot water operation even during cooling or defrosting. In other words, the design of the Fig. 9 This allows for both defrosting and cooling the room, while simultaneously providing hot water. Cooling the room simultaneously serves to heat the water provided.

[0066] Fig. 10 shows schematically and exemplarily a further embodiment of the heating and hot water circuit of the embodiment in Fig. 8 . In addition, a hot water return bypass 17 is arranged, which provides a direct connection between the heating return 28 and the heating flow 27 upstream of the first heat exchanger 3a. A circulation pump 12 is arranged in the hot water return bypass 17, which enables flow through the hot water circuit 26. Furthermore, a heating return bypass 18 is provided, and a heater 25, for example, one or more radiators, is schematically depicted.

[0067] Fig. 11 shows a schematic and exemplary embodiment of another design of the heating and hot water circuit. Here, heating circuit 22 and hot water circuit 26 are designed as separate circuits.

[0068] Fig. 12 shows schematically and exemplarily another design of a hot water bypass 19. Unlike in Fig. 11 The hot water bypass 19 connects directly from the hot water flow 27 in front of a hot water tank 29 to the heating flow 23 in front of the heater 25. Liste der Bezugszeichen

[0069] 1 Compressor 2 Switching valve 3 Heat exchanger device 3a First heat exchanger 3b Second heat exchanger 4 Collector 5 Filter dryer 6 Recuperator 7 Defrost coil 8 Expansion valve 9 Evaporator 10 Inverter cooling 11 Cooling valve 12 Circulation pump 13 Mixer 14 Direct heating 15 Heat pipe 16 Hot water bypass 17 Hot water return bypass 18 Heating return bypass 19 Hot water bypass 20 Heating circuit 22 Heating circuit 23 Heating flow 24 Heating post-run 25 Heating 26 Hot water circuit 27 Hot water flow 28 Hot water post-run 29 Hot water storage tank 30 Heat pump circuit 40 Air inlet 42 Air outlet 44 Safety blow-off 46Heat pump system boundary 100Heating and / or hot water system

Claims

1. A heating and / or hot water heating system (100), comprising a heating circuit (20) and a heat pump circuit (30), wherein the heat pump circuit (30) has a heat exchanging device (3) arranged to transfer heat from the heat pump circuit (30) to the heating circuit (20), wherein the heating circuit (20) comprises a heating loop (22) with heating flow (23) and heating return (24), a hot water loop (26) with hot water flow (27) and hot water return (28), and an adjustable mixer (13), wherein the mixer (13) is arranged to split a volumetric flow through the heating circuit (20) at least between the heating system flow (23) and the hot water flow (27), wherein the heat exchanging device (3) has a first heat exchanger (3a) and a second heat exchanger (3b) in series therewith, wherein the second heat exchanger (3b) is arranged to transfer heat to the heating circuit (20) upstream of the mixer (13), and wherein the first heat exchanger (3a) is arranged to transfer heat to the hot water flow (27) downstream of the mixer (13), wherein the first heat exchanger (3a) is designed as a desuperheater and the second heat exchanger (3b) as a condenser, characterised in that the desuperheater is designed as a heat pipe, thermosiphon and / or heatpipe (15) between the heat pump circuit (30) and the hot water loop (26) and the condenser is designed as a plate heat exchanger, wherein a pressure drop across the first heat exchanger (3a) is less than a pressure drop across the second heat exchanger (3b).

2. The heating and / or hot water heating system (100) according to claim 1, wherein the hot water loop (26) is arranged to heat a hot water storage tank to a required temperature, wherein the mixer (13) is arranged to control the volumetric flow, in particular through the hot water loop (26), such that the temperature in the hot water storage tank follows the required value.

3. The heating and / or hot water heating system (100) according to claim 1 or 2, wherein a circulation pump (12) is disposed in the heating circuit (20).

4. The heating and / or hot water heating system (100) according to any one of the preceding claims, wherein a direct heater (14) is disposed in the hot water flow (27) downstream of the first heat exchanger (3a).

5. The heating and / or hot water heating system (100) according to any one of the preceding claims, wherein a bypass line for diverting a refrigerant circulating through the heat pump circuit (30) is disposed on the first heat exchanger (3a).

6. The heating and / or hot water heating system (100) according to any one of the preceding claims, wherein the heating and / or hot water heating system (100) can be operated in a pure heating mode, a pure hot water mode and a parallel mode of heating mode and hot water mode.

7. The heating and / or hot water heating system (100) according to any one of the preceding claims, wherein, in the heating mode, a minimum volumetric flow through the hot water loop is maintained, wherein the minimum volumetric flow is sized such that boiling in the hot water loop is prevented.

8. The heating and / or hot water heating system (100) according to any one of the preceding claims, wherein the heat pump circuit (30) has a changeover valve (2), wherein the changeover valve (2) is disposed such that, upon changeover of the changeover valve (2), a flow direction of a refrigerant flowing through the heat pump circuit (30) remains the same in the first heat exchanger (3a) and is reversed in the second heat exchanger (3b).

9. The heating and / or hot water heating system (100) according to claim 8, wherein the first heat exchanger (3a) and the second heat exchanger (3b) are disposed on different sides of the changeover valve (2) in the heat pump circuit (30).

10. A method of controlling a heating and / or hot water heating system according to any one of the preceding claims, wherein the method comprises setting a position of a mixer (13) between the heating loop (22) and the hot water loop (26) of a heating circuit (20) in dependence of a temperature of a hot water storage tank.