Heating and hot water heating system and method thereof

Abstract

The invention relates to a method and a heating and hot water preparation system (1) with a refrigerant circuit (3) operable as a heat pump, comprising a first and second heat exchanger (7, 9) configured in series as a gas cooler / condenser, wherein, with respect to a fluid flowing in the intended counterflow direction to the refrigerant through the first heat exchanger (7), the second heat exchanger (9) is arranged upstream of the first heat exchanger (7), and the fluid line (19) between the second and first heat exchangers (9, 7) has a first branch (21) for a branching first fluid line branch (23) with a fluid pump (25) and a third heat exchanger (27), and the fluid line after the first heat exchanger (7) has a second branch (37) into a second fluid line branch (39) opening into the first fluid line branch (23) and into a third fluid line branch (43).wherein the third heat exchanger (27) is connected to a heating circuit (31) which is pump-free from the inlet (29) of the first fluid line branch (23) into the supply line (15) through the second heat exchanger (9) to the first branch (21), and the respective fluid flow rates through the first fluid line branch (23) and the second fluid line branch (39) as well as into the third fluid line branch (43) are continuously adjustable.

Description

Field of technology:

[0001] The invention relates to a heating and hot water preparation system according to the preamble of claim 1. Heating and hot water systems with a refrigerant circuit operable as a heat pump and a first and a second heat exchanger, each designed as a gas cooler / condenser, in which a fluid can be heated in counterflow to the refrigerant, are used in particular for heating and hot water preparation in buildings. Furthermore, the invention also relates to a method for operating such a heating and hot water preparation system. State of the art:

[0002] Heating and hot water systems with a refrigerant circuit operable as a heat pump and having two gas coolers / condensers for heating a fluid are known. EP2759773 A2 discloses such a heating and hot water system in which a buffer storage tank is arranged in the fluid circuit. There, the fluid circuit is designed such that the first heat exchanger, arranged downstream of the compressor in the refrigerant circuit and used as a condenser / gas cooler, is disadvantageously not used for heating the building, which leaves the heat transferred there to the fluid at high temperature unused for heating the building. On the other hand, in EP2759773 A2, the heat transferred from the fluid to the domestic water disadvantageously always occurs at the high temperature of the fluid from the first heat exchanger. In the system disclosed in DE102008046620 A1 with two gas coolers connected in series in the refrigerant circuit, the control of the heat pump is described.A return of fluid to the supply line to the gas coolers is disadvantageously not shown there. US2018 / 0023818 A1 discloses a heating and hot water preparation system in which two heat exchangers connected in series as gas coolers / condensers are arranged in the refrigerant circuit of a heat pump system to heat a fluid in a heating circuit. In the heating system shown in DE102015008045 A1, the heat pump heats a storage medium for a heat storage unit with its two heat exchangers connected in series as gas coolers / condensers in heat pump operation of the refrigerant circuit. A different, regulated heat supply for hot water preparation and heating is disadvantageously not shown there.In contrast, DE102019001642 A1 and WO2019 / 215240 A1 each disclose a heating and hot water preparation system with differently regulated heat supply for hot water preparation and heating, using two heat exchangers connected in series in the refrigerant circuit of a heat pump as gas coolers / condensers. The heat pump is thermally connected to a heating circuit with a heating circuit and a hot water circuit via the two heat exchangers. However, in parallel operation in the heating circuit, its fluid flows through both the heating circuit and the hot water circuit, so that possible contaminants of the fluid in the heating circuit can enter the two heat exchangers, the mixing valve, and the hot water circuit. Furthermore, the volume of the fluid in the heating circuit connected to the two heat exchangers, with the heating circuit and the hot water circuit, is correspondingly large.The fluid pump in the fluid line between the two heat exchangers before the first branching point requires space and material, which impedes a compact design in the area of ​​heat transfer to the fluid. Furthermore, in the heating and hot water systems shown in DE102019001642 A1 and WO2019 / 215240 A1, the controllability of the distribution of the fluid flow remaining after the two heat exchangers into the hot water circuit and / or the heating circuit is only possible to a limited extent, if at all.

[0003] The invention defined in claim 1 is therefore based on the problem that the flexibility with regard to heating and / or hot water preparation in existing heating and hot water preparation systems is insufficient, the space requirement in the area of ​​heat transfer to the fluid is excessive, and contaminants from the heating circuit in the fluid can enter the hot water preparation area. The object is therefore to provide a heating and hot water preparation system with a refrigerant circuit that can be operated as a heat pump, which is improved, particularly with regard to this problem.

[0004] A corresponding task exists for a method for operating such a heating and hot water system. Summary of the invention:

[0005] The problem underlying the invention defined in claim 1 is solved by the features set out in claim 1. In that the heating and hot water preparation system comprises a refrigerant circuit operable as a heat pump with at least one expansion element, at least one evaporator, at least one compressor, a first heat exchanger designed as a gas cooler / condenser for transferring heat of the compressed refrigerant to a fluid, such as preferably water, and a second heat exchanger designed as a gas cooler / condenser, connected in series downstream of the first heat exchanger in the refrigerant flow direction, for transferring heat of the refrigerant to the fluid, and the heating and hot water preparation system is designed in such a way,that with regard to the fluid that can flow through the first heat exchanger in the intended counterflow direction to the coolant, the second heat exchanger is arranged upstream of the first heat exchanger, and the fluid line for the fluid has a first branch between the second and first heat exchanger, and a first fluid line branch branching off at the first branch opens into a supply line for the fluid before or at the fluid inlet of the second heat exchanger, and the fluid line after the first heat exchanger has a second branch into a second fluid line branch and a third fluid line branch, wherein a fluid pump is arranged in the first fluid line branch for the fluid, and the first fluid line branch comprises a third heat exchanger on the fluid side, which is connected to a heating circuit for transferring heat from the fluid to a heating fluid,and the second fluid line branch opens into the first fluid line branch upstream of both the fluid pump and the third heat exchanger in the intended fluid flow direction of the first fluid line branch, and the fluid line section running from the junction of the first fluid line branch into the supply line through the second heat exchanger to the first branch is pump-free, and the heating and hot water preparation system is designed such that the respective volume flows of the fluid through the first fluid line branch and the second fluid line branch as well as into the third fluid line branch are controllable, wherein the heating and hot water preparation system comprises continuously controllable control valves for this control, the object is achieved.

[0006] A heat exchanger designed as a gas cooler / condenser can be a condenser for refrigerant to be operated subcritically in the high-pressure area of ​​the refrigerant circuit or a gas cooler for refrigerant to be operated supercritically in the high-pressure area of ​​the refrigerant circuit, or it can be designed in such a way that it can be used both as a gas cooler and as a condenser.

[0007] The heating and hot water system has the advantage of being able to control the fluid flow rates through the three fluid line branches, providing a high degree of flexibility for heating and hot water production. A further advantage is that the heating circuit is a separate circuit for the heating fluid and is thermally connected to the first fluid line branch via the third heat exchanger. This prevents contaminants from the heating circuit from entering the fluid, and the fluid heated by the heat pump does not need to flow through the heating circuit volume, making the system less cumbersome.Another advantage is that the fluid line section running from the junction of the first fluid line branch into the supply line through the second heat exchanger to the first branch is pump-free, as this allows this area of ​​the heating and hot water system to be constructed in a space- and material-saving manner, whereby the pressure of the fluid already applied in the supply line can be used.

[0008] The continuously adjustable control valves for regulating the respective fluid flow rates through the first fluid line branch and the second fluid line branch, as well as into the third fluid line branch, are also advantageous. This increases the flexibility and precision of regulating these fluid flow rates.

[0009] The subclaims specify advantageous embodiments, further developments and improvements of the respective subject matter of the invention.

[0010] According to an advantageous embodiment, the control valves for regulating the respective fluid flow rates are at least two continuously adjustable three-way valves, one of which is arranged in the first branch and the other in the second branch. This provides particularly good flexibility and precision for regulating these fluid flow rates.

[0011] The refrigerant circuit is preferably designed such that the refrigerant, preferably CO2, is supercritical in the high-pressure section of the refrigerant circuit, and the first heat exchanger and second heat exchanger are operated as gas coolers, with the first heat exchanger serving as a desuperheater. The refrigerant lines and components of the high-pressure section of the refrigerant circuit must be sufficiently pressure-resistant to withstand refrigerant pressures of up to 150 bar. This improves the effectiveness of the heat pump, especially at low heat source temperatures.

[0012] According to a further advantageous embodiment of the heating and hot water preparation system, at least one of the at least one evaporator is designed as a refrigerant-liquid heat exchanger and is arranged in the refrigerant circuit to transfer heat from a heat source liquid, such as preferably a brine of a liquid circuit, to the refrigerant. The heat source can be located away from the evaporator.

[0013] Preferably, the first and second heat exchangers are combined to form a single heat transfer unit. This is a particularly compact and thus space-saving and material-saving design.

[0014] Preferably, the fluid pump in the first fluid line branch is designed as a water pump with continuously variable pumping capacity. This allows the volume flow of the fluid through the third heat exchanger to be easily controlled, improving the flexibility and precision of heat transfer from the fluid to the heating fluid in the heating circuit.

[0015] According to an advantageous development of the heating and hot water preparation system, it is designed such that the first fluid line branch can be shut off after the second fluid line branch flows into it, and the fluid flow direction in the second fluid line branch can be switched. This increases the flexibility of hot water preparation, because the proportion of the volume flow of the fluid preheated in the second heat exchanger into the third fluid line branch, which also flows through the first heat exchanger to further heat the fluid, can be regulated. This improves the adjustment of the fluid temperature for the third fluid line branch and thus for hot water preparation.

[0016] Preferably, the third fluid line branch leads to a hot water storage tank connected to the third fluid line branch and / or to a hot water outlet.

[0017] The fluid can therefore be used as a storage medium and / or directly as hot water.

[0018] According to an advantageous development of the heating and hot water preparation system, the third fluid line branch is part of a fluid circuit in which the fluid can be circulated, bypassing the third heat exchanger, through the supply line, the second and first heat exchangers, and back to the supply line. A particularly advantageous embodiment is one in which the third fluid line branch leads to a fourth heat exchanger arranged in the fluid circuit for transferring heat from the fluid to domestic water. With such indirect hot water preparation, the fluid circuit can be kept small.

[0019] Preferably, the heating and hot water preparation system comprises a controller configured to control the respective volume flows of the fluid through the first fluid line branch and the second fluid line branch, as well as into the third fluid line branch, such that the heating and hot water preparation system can be operated in a pure heating mode, in a pure hot water preparation mode, and in a first parallel operation consisting of reduced heating mode and hot water preparation mode, as well as in a second parallel operation consisting of heating mode and hot water preparation mode. Thus, these four operating modes can be automatically set and controlled alternatively using the controller.In the first parallel operation with reduced heating operation, only fluid heated in the second heat exchanger reaches the third heat exchanger, whereas in the second parallel operation with non-reduced heating operation, the fluid flowing through the third heat exchanger was heated in the second and first heat exchanger.

[0020] The problem underlying the invention with regard to a method for operating a heating and hot water system is solved by a method having the features of claim 12. Due to the fact that the method for operating a heating and hot water system according to the invention comprises the four operating modes a) pure heating operation, in which the fluid flows through the third heat exchanger to heat the heating fluid of the heating circuit and no fluid flows into the third fluid line branch, b) pure hot water preparation operation, in which the fluid flows into the third fluid line branch and no fluid flows through the third heat exchanger on the fluid side, c) first parallel operation, of reduced heating operation and hot water preparation operation, in which no fluid flows through the second fluid line branch and, at the first branch arranged between the second and first heat exchanger, the fluid flows, on the one hand, into the first fluid line branch to the third heat exchanger for heating the heating fluid of the heating circuit and, on the other hand, through the first heat exchanger into the third fluid line branch, and d) second parallel operation of heating operation and hot water preparation operation,in which no fluid flows into the first fluid line branch at the first branch arranged between the second and first heat exchanger, and the fluid at the second branch after the first heat exchanger is divided into the second fluid line branch to the third heat exchanger for heating the heating fluid of the heating circuit and flows into the third fluid line branch, includes, the task is solved.

[0021] The advantages and relevant information above for the heating and hot water preparation system according to the invention apply accordingly to the method according to the invention.

[0022] According to an advantageous development of the method according to the invention, it also includes, as an operating mode for the heating and hot water preparation system, a mixed operation of the first and second parallel operation, with the mixing ratio being adjustable, wherein the fluid flow at the first branch and that at the second branch are respectively divided. With this additional mixed operation of two operating modes, the heating and hot water preparation system can be operated more flexibly in parallel operation of heating and hot water preparation.

[0023] According to a further advantageous embodiment of the method according to the invention, it has a further operating mode in which, in the pure hot water preparation operation, a part of the fluid flows through the first heat exchanger in a controlled distribution ratio at the first branch and the other part of the fluid flows to the second fluid line branch and through this to the second branch, in which both partial flows of the fluid are reunited and flow further into the third fluid line branch. With this additional operating mode of the pure

[0024] The heating and hot water system can be operated more flexibly during hot water preparation. This improves the adjustment of the fluid temperature for the third fluid line branch.

[0025] The method preferably comprises a further operating mode in which, during pure heating operation, a portion of the fluid flows through the first heat exchanger and further through the second fluid line branch after the second branch, divided at the first branch according to a controlled distribution ratio, and the other portion of the fluid flows directly from the first branch through the first fluid line branch, with both partial fluid flows reuniting upstream of the third heat exchanger. This additional operating mode of pure heating operation allows the heating and hot water system to be operated more flexibly when heating the heating fluid in the heating circuit. This improves the adjustment of the fluid temperature in the third heat exchanger. Short description of the drawings:

[0026] Embodiments of the invention are explained with reference to the drawings.

[0027] It shows Fig. 1 a schematic representation of an embodiment of a heating and hot water system; Fig. 2 in schematic representation the Fig. 1 shown embodiment of a heating and hot water preparation system in the operating mode of pure hot water preparation; Fig. 3 in schematic representation the Fig. 1 shown embodiment of a heating and hot water preparation system in the operating mode of pure heating operation; Fig. 4 in schematic representation the Fig. 1 shown embodiment of a heating and hot water preparation system in the operating mode of the first parallel operation of hot water preparation and reduced heating; Fig. 5 in schematic representation the Fig. 1 shown embodiment of a heating and hot water preparation system in the operating mode of the second parallel operation of hot water preparation and non-reduced heating; Fig. 6in schematic representation the Fig. 1 shown embodiment of a heating and hot water preparation system in the further operating mode of pure hot water preparation; Fig. 7 a schematic representation of another embodiment of a heating and hot water system; and Fig. 8 as a flowchart an embodiment of a method for operating a heating and hot water system according to the invention. Detailed description of the invention:

[0028] In Figure 1An exemplary embodiment of a heating and hot water preparation system 1 according to the invention is shown schematically. The refrigerant circuit 3, which can be operated as a heat pump, comprises a compressor 5, a first heat exchanger 7 designed as a gas cooler / condenser, a second heat exchanger 9 designed as a gas cooler / condenser and connected in series downstream in the refrigerant flow direction, an expansion element 11 designed as an expansion valve, and an evaporator 13 designed as a refrigerant-air heat exchanger. Also conceivable is an evaporator 13 which is a refrigerant-liquid heat exchanger and is arranged in the refrigerant circuit 3 for transferring heat from a heat source liquid, such as brine, of a liquid circuit to the refrigerant.

[0029] The refrigerant in this case is CO2. The refrigerant circuit is designed so that the refrigerant operates supercritically in its high-pressure region, and the first heat exchanger 7 and the second heat exchanger 9 can be operated as gas coolers, with the first heat exchanger 7 serving as a desuperheater. A design is also conceivable in which refrigerant, such as R1234yf, can be operated subcritically in the high-pressure region of the refrigerant circuit 3, in which case the first and second heat exchangers 7, 9 are condensers.

[0030] The first heat exchanger 7 and the second heat exchanger 9 each serve to transfer heat from the refrigerant to a fluid. In this case, the fluid used is water. For fluid flowing through the first heat exchanger 7 in a countercurrent direction to the refrigerant, the second heat exchanger 9 is arranged upstream of the first heat exchanger 7. Both are designed as refrigerant-liquid heat exchangers, such as plate heat exchangers, with water being provided as the fluid. The fluid, coming from the supply line 15 at a correspondingly high water pressure of, for example, eight bar, flows to the fluid inlet 17 of the second heat exchanger 9 and further through the second heat exchanger 9 and through the fluid line 19 to the first branch 21. There, the first fluid line branch 23 branches off from the fluid line 19.It has a fluid pump 25 designed as a continuously variable water pump and, on the fluid side, the third heat exchanger 27 and leads to the inlet 29 in the supply line 15 before or at the fluid inlet 17 of the second heat exchanger 9. The third heat exchanger 27 is, on the other hand, connected to a heating circuit 31 and serves to transfer heat from the fluid to the heating fluid of the heating circuit 31. The heated heating fluid, pumped in counterflow to the fluid flow through the third heat exchanger 27 with the circulation pump 33, flows to the heating devices 35, such as radiators or pipes of an underfloor heating system, for heating a building and then back again in the heating circuit 31 to the third heat exchanger 27.

[0031] The part of the fluid flow that does not branch off into the first fluid line branch 23 at the first branch 21 flows to the fluid side of the first heat exchanger 7 in order to absorb additional heat from the refrigerant therein and then flow on to the second branch 37. At the second branch 37, the fluid line coming from the first heat exchanger 7 splits into the second fluid line branch 39 and the third fluid line branch 43. The second fluid line branch 39 opens into the first fluid line branch 23 at the line connection 41, upstream of both the fluid pump 25 and the third heat exchanger 27 in the intended fluid flow direction of the first fluid line branch 23. The third fluid line branch 43 further leads to a hot water tank connected to it and / or to a water outlet for hot water. The hot water tank and / or water outlet are shown in the figure for reasons of clarity. Figure 1not shown. After flowing through the second heat exchanger 9, the fluid has a temperature level between, for example, 35 °C and 45 °C, and after flowing further through the first heat exchanger 7, the fluid has a temperature level between, for example, 60 °C and 75 °C.

[0032] The fluid line section extending from the junction 29 of the first fluid line branch 23 into the supply line 15 through the second heat exchanger 9 to the first branch 21 is pump-free. The flow of the fluid through this fluid line section is generated primarily by the water pressure present in the supply line 15.

[0033] The heating and hot water preparation system 1 is designed such that the respective volume flows of the fluid through the first fluid line branch 23 and the second fluid line branch 39, as well as into the third fluid line branch 43, can be regulated. For this purpose, a continuously adjustable three-way valve is arranged as a control valve in the first branch 21 and in the second branch 37, both of which are automatically controlled by the controller 45. The controller 45 also controls the output of the compressor 5 of the refrigerant circuit 3, which can be operated as a heat pump, the fluid pump 25 in the first fluid line branch 23, and the circulation pump 33 in the heating circuit 31.

[0034] The heating and hot water system 1 can be used, for example, for buildings or vehicles. A variant of the one shown in Figure 1

[0035] The exemplary embodiment combines the first heat exchanger 7 and the second heat exchanger 9 into a heat transfer unit. On the one hand, the first fluid line branch 23 branches off at the first branch 21 directly after the second heat exchanger 9, and on the other hand, the first heat exchanger 7 is directly connected to the first branch 21 on the fluid side.

[0036] In the Figures 2 to 6 are different operating modes of the Figure 1 shown embodiment of a heating and hot water preparation system 1. The reference numerals are unchanged from those in Figure 1 . Unused lines and components are shown in dashed lines.

[0037] In Figure 2 The heating and hot water preparation system 1 is shown schematically in the operating mode of pure hot water preparation.

[0038] Compressor 5 is switched on, so that the refrigerant circulates in heat pump mode in refrigerant circuit 3. The refrigerant, which is hot due to compression, first passes from compressor 5 into the first heat exchanger 7, where it transfers heat to the fluid flowing there in countercurrent. Accordingly cooled, the refrigerant, which is at least still warm, passes into the second heat exchanger 9, where it transfers further heat to the fluid flowing there in countercurrent from supply line 15. In the downstream expansion element 11, the refrigerant is expanded and cooled. The condensed refrigerant then absorbs heat from the ambient air in the evaporator 13 and evaporates, before returning to compressor 5.

[0039] The fluid to be heated, coming from the supply line 15, flows through the second heat exchanger 9 to absorb heat from the refrigerant and then through the fluid line 19 to the first branch 21. The three-way valve in the first branch 21 is controlled by the controller 45 such that the branch into the first fluid line branch 23 is shut off and the volume flow of the fluid is directed undivided to the first heat exchanger 7. In this, the fluid is further heated and directed to the second branch 37. The three-way valve there is controlled by the controller 45 such that the second fluid line branch 39 is shut off and the volume flow of the heated fluid is directed undivided into the third fluid line branch 43, through which it reaches the hot water tank and / or the hot water outlet.

[0040] In this pure hot water preparation operation of the heating and hot water preparation system 1, the first fluid line branch 23 and the second fluid line branch 39 are not flowed through by fluid and the fluid pump 25, the third heat exchanger 27 and the heating circuit 31 are out of function.

[0041] In Figure 3 The heating and hot water system 1 is shown schematically in the operating mode of pure heating operation.

[0042] Compressor 5 is switched on so that the refrigerant circulates in refrigerant circuit 3 in heat pump operation.

[0043] The fluid to be heated, coming from the inlet 29 into the supply line 15, flows through the second heat exchanger 9 to absorb heat from the refrigerant and then through the fluid line 19 to the first branch 21. The three-way valve in the first branch 21 is controlled by the controller 45 such that the branch into the first fluid line branch 23 is shut off and the volume flow of the fluid is directed undivided to the first heat exchanger 7. In this, the fluid is further heated and directed to the second branch 37. The three-way valve there is controlled by the controller 45 such that the third fluid line branch 43 is shut off and the volume flow of the heated fluid is directed undivided into the second fluid line branch 39, through which it reaches the first fluid line branch 23 at the line connection 41.There, the fluid pump 25, controlled by the controller 45, pumps the fluid through the third heat exchanger 27 back to the inlet 29 in the supply line 15, from where it flows again to the second heat exchanger 9. In the third heat exchanger 27, the fluid transfers heat to the heating fluid of the heating circuit 31, which flows there in the counterflow direction. The circulation pump 33 is switched on under the control of the controller 45. In the heating devices 35, the heat absorbed by the heating fluid is used to heat the building.

[0044] In this pure heating mode of the heating and hot water preparation system 1, the fluid is heated only for heating purposes, absorbing heat from the refrigerant in the second and first heat exchangers 9 and 7. No fluid is added from the outside through the supply line 15 because no fluid flows out as hot water through the third fluid line branch 43. The switched-on, regulated fluid pump 25 circulates the fluid in a controlled volume flow.

[0045] In Figure 4 The heating and hot water preparation system 1 is shown schematically in the operating mode of the first parallel operation of hot water preparation and reduced heating.

[0046] Compressor 5 is switched on so that the refrigerant circulates in refrigerant circuit 3 in heat pump operation.

[0047] The fluid to be heated, coming from the supply line 15, flows through the second heat exchanger 9 to absorb heat from the refrigerant and then through the fluid line 19 to the first branch 21. The three-way valve in the first branch 21 is controlled by the controller 45 such that one portion of the fluid flow branches off into the first fluid line branch 23 and the other portion of the fluid flow is directed to the first heat exchanger 7. In the first heat exchanger 7, this other portion of the fluid flow is further heated and directed to the second branch 37. The three-way valve there is controlled by the controller 45 such that the second fluid line branch 39 is shut off and the portion of the fluid flow additionally heated in the first heat exchanger 7 is directed into the third fluid line branch 43, through which the fluid reaches the hot water tank and / or the hot water outlet.

[0048] The portion of the fluid flow branching off at the first branch 21 into the first fluid line branch 23 is pumped by the fluid pump 25 through the third heat exchanger 27 back to the inlet 29 into the supply line 15, from where it flows again to the second heat exchanger 9. In the third heat exchanger 27, the fluid transfers heat to the heating fluid of the heating circuit 31, which flows there in the counterflow direction. The circulation pump 33 is switched on under the control of the controller 45. In the heating devices 35, the heat absorbed by the heating fluid is used to heat the building.

[0049] In this first parallel operation with hot water preparation and reduced heating, no fluid flows through the second fluid line branch 39, so that only fluid heated in the second heat exchanger 9 reaches the third heat exchanger 27 for heating. Because this portion of the fluid in the first heat exchanger 7 does not absorb heat from the hotter refrigerant there, the temperature of this partial fluid flow is not as high, so that less heat is transferred to the heating fluid in the third heat exchanger 27 at a lower temperature, thus the heating is operated at a reduced level.

[0050] The controller 45 controls the ratio of the size of the volume flows of the two partial flows of the fluid by continuously regulating the three-way valve of the first branch 21 and the fluid pump 25. This allows the proportion for hot water preparation and the proportion for reduced heating to be continuously adjusted as required.

[0051] In Figure 5The heating and hot water preparation system 1 is shown schematically in the operating mode of the second parallel operation of hot water preparation and non-reduced heating.

[0052] Compressor 5 is switched on so that the refrigerant circulates in refrigerant circuit 3 in heat pump operation.

[0053] The fluid to be heated, coming from the supply line 15, flows through the second heat exchanger 9 to absorb heat from the refrigerant and then through the fluid line 19 to the first branch 21. The three-way valve in the first branch 21 is controlled by the controller 45 such that the branch into the first fluid line branch 23 is shut off and the volume flow of the fluid is directed undivided to the first heat exchanger 7. In this, the fluid is further heated and directed to the second branch 37. The three-way valve there is controlled by the controller 45 such that the fluid flow is divided, with one part of the fluid flow branching into the second fluid line branch 39 and the other part of the fluid flow being directed into the third fluid line branch 43, through which the fluid reaches the hot water tank and / or the hot water outlet.The portion of the fluid flow branching into the second fluid line branch 39 flows into the first fluid line branch 23 at the line connection 41 and is pumped by the fluid pump 25 through the third heat exchanger 27 back to the inlet 29 into the supply line 15, from where the fluid flows again to the second heat exchanger 9. In the third heat exchanger 27, the fluid transfers heat to the heating fluid of the heating circuit 31, which flows there in the counterflow direction. The circulation pump 33 is switched on under the control of the controller 45. In the heating devices 35, the heat absorbed by the heating fluid is used to heat the building.

[0054] In this second parallel operation with hot water preparation and non-reduced heating, fluid flows through the second fluid line branch 39, so that only fluid heated in both the second heat exchanger 9 and the first heat exchanger 7 reaches the third heat exchanger 27 for heating. Because this part of the fluid additionally absorbs heat from the significantly hotter refrigerant in the first heat exchanger 7, the temperature of this partial flow is correspondingly high, so that in the third heat exchanger 27, more heat is transferred to the heating fluid at a correspondingly higher temperature than in reduced heating operation, i.e. the heating is not operated at a reduced temperature.

[0055] The controller 45 controls the ratio of the size of the volume flows of the two partial flows of the fluid by continuously regulating the three-way valve of the second branch 37 and the fluid pump 25. This allows the proportion for hot water preparation and the proportion for non-reduced heating to be continuously adjusted as required.

[0056] In Figure 6 The heating and hot water preparation system 1 is shown schematically in another operating mode of pure hot water preparation.

[0057] Compressor 5 is switched on so that the refrigerant circulates in refrigerant circuit 3 in heat pump operation.

[0058] The fluid to be heated, coming from the supply line 15, flows through the second heat exchanger 9 to absorb heat from the refrigerant and then through the fluid line 19 to the first branch 21. The three-way valve in the first branch 21 is controlled by the controller 45 such that the volume flow of the fluid is divided, with one part being directed into the first fluid line branch 23 and the other part of the fluid flow to the first heat exchanger 7. In the first heat exchanger 7, this part of the fluid flow is further heated and directed to the second branch 37.The portion of the fluid flow branched into the first fluid line branch 23 at the first branch 21 flows at the line connection 41 into the second fluid line branch 39, which is connected in the opposite fluid flow direction, to the second branch 37 and not further in the direction of the third heat exchanger 27, because the fluid pump 25 is switched off by the controller 45 and thus blocks the fluid line of this area of ​​the first fluid line branch 23. In the three-way valve of the second branch 37, which is activated by the controller 45, the two partial fluid flows recombine and flow as a total volume flow into the third fluid line branch 43, through which the fluid reaches the hot water tank and / or the hot water outlet.

[0059] In this pure hot water preparation mode of the heating and hot water preparation system 1, the fluid pump 25, the third heat exchanger 27, and the heating circuit 31 are deactivated. The controller 45 controls the ratio of the volume flow rates of the two partial fluid flows by continuously regulating the three-way valve of the first branch 21. This continuously regulates the portion of hot water preparation in which the water is additionally heated in the first heat exchanger 7, and thus adjusts the temperature of the entire hot water flow flowing through the third fluid line branch 43 to meet demand.

[0060] In Figure 7 A further embodiment of a heating and hot water preparation system 1 is shown schematically. It corresponds in large parts to the one shown in Figure 1 shown example. All of the required Figure 1 Reference symbols used in Figure 7used for identical components, whereby the evaporator 13 in this case is a refrigerant-liquid heat exchanger and serves to absorb the heat of the refrigerant from a heat source liquid of a liquid circuit 55, in which heat source liquid is transported from a heat source to the evaporator 13 by means of a pump 57 controllable by the controller 45. The heat source liquid is, for example, a brine. Otherwise, the structure of the refrigerant circuit 3 with its components corresponds to that in Figure 1 The heating circuit 31 connected to the third heat exchanger 27 with circulation pump 33 and heating devices 35 also corresponds to the Figure 1 . In addition, the arrangement of the fluid lines with the first, second and third fluid line branches 23, 39, 44, the three heat exchangers 7, 9, 27, the first and second branches 21, 37 and their continuously adjustable three-way valves from Figure 1However, the fluid pump 25 is positioned in the first fluid line branch 23 downstream of the third heat exchanger 27. Furthermore, the third fluid line branch 43 in this case is part of a fluid circuit 47 in which the fluid can be circulated, bypassing the third heat exchanger 27, through the supply line 15, the second and first heat exchangers 9, 7, and back to the supply line 15. In the section from the third fluid line branch 43 to the supply line 15, a fourth heat exchanger 51 and a fluid pump 49 for pumping the fluid into the supply line 15 to the second heat exchanger 9 are arranged in the fluid circuit 47. The fluid is water or another suitable fluid for heat transport, such as a suitable oil or gas. The fourth heat exchanger 51 serves to transfer heat of the fluid to a domestic water, which can flow there in countercurrent to the fluid and further through the hot water pipe 53.The domestic water can therefore be heated indirectly via the fluid circuit 47 by the refrigerant circuit 3, which operates as a heat pump. The domestic water heated in this way can be used as hot water.

[0061] The operating modes of the control system 45 that can be set in Figure 7 shown heating and hot water preparation system 1 corresponding to those for the Figures 2 to 6 described.

[0062] The heating and hot water system 1 can be used, for example, for buildings or vehicles.

[0063] Figure 8 shows a flow chart of an embodiment of a method for operating a heating and hot water preparation system according to the invention, such as one of the systems described in Figures 1 and 7 systems shown.

[0064] In the first step 100, the demand for hot water and heating for the building or vehicle for which the heating and hot water system is used is determined. In the second step 110, the results of step 100 are used to decide which of the Figures 2 to 6described operating modes of pure hot water preparation, pure heating operation, first and second parallel operation are selected. In steps 120A to 120E, which follow depending on the selected operating mode, the fine adjustment of the respective operating mode takes place depending on the demand determined in step 100. Thus, in the two parallel operations, the distribution of the two fluid flows for heating and hot water is continuously adjusted by the controller according to the determined demand. In pure hot water preparation operation, the size of the portion of the fluid flow that also flows through the first heat exchanger is adjusted by the controller depending on the determined demand.In pure heating operation, the size of the proportion of reduced heating and non-reduced heating is adjusted according to the determined requirement, i.e. the distribution ratio is regulated so that part of the fluid flow also flows through the first heat exchanger and further after the second branch through the second fluid line branch and the other part of the fluid flow flows from the first branch directly through the first fluid line branch, and both partial flows of the fluid reunite upstream of the third heat exchanger.

[0065] After a predetermined period of time, for example 10 seconds, the process begins again after the steps 120A to 120E which run alternatively to one another.

[0066] It is conceivable in step 110, when selecting the operating modes of the heating and hot water preparation system according to the invention, that a mixed operation of first and second parallel operation is included, wherein the fluid flow at the first branch and that at the second branch are each divided.

Claims

1. A heating and hot water preparation system (1) comprising a refrigerant circuit (3) operable as a heat pump, having at least one expansion element (11), at least one evaporator (13), at least one compressor (5), a first heat exchanger (7) configured as a gas cooler / condenser for transferring heat of the compressed refrigerant to a fluid, such as preferably water, and a second heat exchanger (9) configured as a gas cooler / condenser, connected in series downstream of the first heat exchanger (7) in the refrigerant flow direction, for transferring heat of the refrigerant to the fluid, and wherein the heating and hot water preparation system (1) is configured such that, with respect to the fluid flowing through the first heat exchanger (7) in the intended counterflow direction to the refrigerant, the second heat exchanger (9) is arranged upstream of the first heat exchanger (7).and the fluid line (19) for the fluid between the second and first heat exchanger (9, 7) has a first branch (21) and a first fluid line branch (23) branching off at the first branch (21) opens into a supply line (15) for the fluid before or at the fluid inlet (17) of the second heat exchanger (9), and the fluid line after the first heat exchanger (7) has a second branch (37) into a second fluid line branch (39) and a third fluid line branch (43), characterized in that- a fluid pump (25) is arranged in the first fluid line branch (23) for the fluid; - the first fluid line branch (23) comprises, on the fluid side, a third heat exchanger (27) which is connected to a heating circuit (31) for transferring heat from the fluid to a heating fluid; - the second fluid line branch (39) opens into the first fluid line branch (23) upstream of both the fluid pump (25) and the third heat exchanger (27) in the intended fluid flow direction of the first fluid line branch (23); - the fluid line section running from the junction (29) of the first fluid line branch (23) into the supply line (15) through the second heat exchanger (9) to the first branch (21) is pump-free;and - the heating and hot water preparation system (1) is designed such that the respective volume flows of the fluid through the first fluid line branch (23) and the second fluid line branch (39) as well as into the third fluid line branch (43) are controllable, wherein the heating and hot water preparation system (1) comprises continuously controllable control valves for this control.; 2. Heating and hot water systems (1) according to claim 1 characterized in that the control valves for controlling the respective volume flows of the fluid are at least two continuously adjustable three-way valves, one of which is arranged in the first branch (21) and the other in the second branch (37).

3. Heating and hot water preparation system (1) according to claim 1 or 2 characterized in thatthe refrigerant circuit (3) is designed such that the refrigerant, such as preferably CO2, is supercritical in the high-pressure region of the refrigerant circuit (3) and the first heat exchanger (7) and second heat exchanger (9) are to be operated as gas coolers, wherein the first heat exchanger (7) is a desuperheater.

4. Heating and hot water preparation system (1) according to one of claims 1 to 3 characterized in that at least one of the at least one evaporator (13) is designed as a refrigerant-liquid heat exchanger and is arranged in the refrigerant circuit (3) for transferring heat from a heat source liquid, such as preferably a brine of a liquid circuit (55), to the refrigerant.

5. Heating and hot water preparation system (1) according to one of claims 1 to 4 characterized in that the first and second heat exchangers (7, 9) are joined together to form a heat transfer unit.

6. Heating and hot water preparation system (1) according to one of claims 1 to 5 characterized in that the fluid pump (25) in the first fluid line branch (23) is designed as a water pump with continuously variable pumping power.

7. Heating and hot water preparation system (1) according to one of claims 1 to 6 characterized in that it is designed such that the first fluid line branch (23) can be shut off after the second fluid line branch (39) opens into the latter and the fluid flow direction in the second fluid line branch (39) can be switched over.

8. Heating and hot water preparation system (1) according to one of claims 1 to 7 characterized in that the third fluid line branch (43) leads to a hot water storage tank connected to the third fluid line branch (43) and / or to a hot water outlet.

9. Heating and hot water preparation system (1) according to one of claims 1 to 8 characterized in thatthe third fluid line branch (43) is part of a fluid circuit (47) in which the fluid can be circulated by bypassing the third heat exchanger (27) through the supply line (15), the second and first heat exchangers (9, 7) until it reaches the supply line (15) again.

10. Heating and hot water preparation system (1) according to claim 9 characterized in that the third fluid line branch (43) leads to a fourth heat exchanger (51) arranged in the fluid circuit (47) for transferring heat of the fluid to a service water.

11. Heating and hot water preparation system (1) according to one of claims 1 to 10 characterized in thatit comprises a control (45) designed in such a way that the control of the respective volume flows of the fluid through the first fluid line branch (23) and the second fluid line branch (39) as well as into the third fluid line branch (43) can be controlled in such a way that the heating and hot water preparation system (1) can be operated in a pure heating operation, in a pure hot water preparation operation and in a first parallel operation consisting of reduced heating operation and hot water preparation operation and in a second parallel operation consisting of heating operation and hot water preparation operation.

12. Method for operating a heating and hot water system (1) according to one of claims 1 to 11 characterized in thatit comprises the four operating modes a) pure heating operation (120A), in which, in order to heat the heating fluid of the heating circuit (31), the fluid flows through the third heat exchanger (27) and no fluid flows into the third fluid line branch (43); b) pure hot water preparation operation (120B), in which the fluid flows into the third fluid line branch (43) and no fluid flows through the third heat exchanger (27) on the fluid side; c) first parallel operation (120C) of reduced heating operation and hot water preparation operation, in which no fluid flows through the second fluid line branch (39) and in the first branch (21) arranged between the second and first heat exchangers (9, 7), the fluid is divided into the first fluid line branch (23) to the third heat exchanger (27) for heating the heating fluid of the heating circuit (31) and flows further through the first heat exchanger (7) into the third fluid line branch (43);and d) second parallel operation (120D) of heating operation and hot water preparation operation, in which no fluid flows into the first fluid line branch (23) at the first branch (21) arranged between the second and first heat exchangers (9, 7) and the fluid at the second branch (37) after the first heat exchanger (7) is divided into the second fluid line branch (39) to the third heat exchanger (27) for heating the heating fluid of the heating circuit (31) and flows into the third fluid line branch (43).

13. Method according to claim 12 characterized in that as an operating mode for the heating and hot water preparation system (1) it also comprises a mixed operation of the first and second parallel operation (120C, 120D) which can be regulated in the mixing ratio, wherein the fluid flow at the first branch (21) and that at the second branch (37) are each divided.

14. Method according to claim 12 or 13 characterized in thatin pure hot water preparation operation in a further operating mode (120E) in the distribution ratio regulated at the first branch (21), a part of the fluid flows through the first heat exchanger (7) and the other part of the fluid flows to the second fluid line branch (39) and through this to the second branch (37), in which both partial flows of the fluid are reunited and flow further into the third fluid line branch (43).

15. Method according to one of claims 12 to 14 characterized in thatin pure heating operation in a further operating mode in the distribution ratio regulated at the first branch (21), a part of the fluid flows through the first heat exchanger (7) and further after the second branch (37) through the second fluid line branch (39) and the other part of the fluid flows from the first branch (21) directly through the first fluid line branch (23), and both partial flows of the fluid reunite upstream of the third heat exchanger (27).

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