EP4050269B1 - Heating device, heating system and method - Google Patents

Description

The invention relates to a heating device according to patent claim 1, a heating system according to patent claim 11 and a method according to patent claim 12.

State of the art

From the EP 2 853 844 A1 A method for defrosting a heat pump that has a refrigerant circuit with a compressor, a condenser and an evaporator is known. A controllable, variable-speed fan is assigned to the evaporator.

From the EP 3 225 922 A1 is a cooling, air conditioning or heating system of a building which includes a circuit for changing the temperature of the building and a hot water heating circuit with a hot water storage tank.

From the WO 2009/096256 A1 A water heater comprising a heat pump unit, a hot water tank, a hot water heat exchanger and a heating circulation circuit is known.

From the EP 3 730 844 A2 A heating and hot water supply system is known, comprising a refrigerant circuit with a consumption-side heat exchanger, a heat transfer medium circuit in which the heat transfer medium heated by the refrigerant is conveyed to a load-side heat exchanger, a hot water storage section provided in the heat transfer medium circuit parallel to the consumption-side heat exchanger, and a control device.

disclosure of the invention

It is an object of the invention to provide an improved heating device, an improved heating system and an improved method for de-icing a heating device.

This object is achieved by means of a heating device according to patent claim 1, a heating system according to patent claim 11 and a method according to patent claim 12.

Advantageous embodiments are specified in the dependent claims.

It has been recognized that an improved heating device for heating a building can be provided in that the heating device has a heat pump with a first heat exchanger. The heating device also has a hot water storage tank for drinking water with a storage tank and a hot water heat exchanger arranged in the storage tank. The heating device also has a heat fluid transport device with a primary circuit pump, at least one first heating circuit connection and a second heating circuit connection. The heat fluid transport device can be filled with a heat fluid. The heat fluid transport device is designed to transport and distribute the heat fluid. A first secondary side of the first heat exchanger is fluidically connected to the first and/or second heating circuit connection. In addition to the hot water storage tank, the heat fluid transport device also has a small storage tank with a storage container for temporarily storing the heat fluid. The storage container is thermally insulated and has a significantly smaller capacity for temporarily storing the heat fluid than the storage tank. The small storage tank is fluidically connected to the first heating circuit connection and/or to the first secondary side of the first heat exchanger. The primary circuit pump is designed to pump the heat fluid between the first secondary side and the small storage tank.

The small storage tank has the advantage that in addition to a first heating circuit that can be connected to the first heating circuit connection, a second heat can be temporarily stored in the small storage tank by means of the heat fluid, so that Even when the first heating circuit is closed or the first heating circuit is slightly open, sufficient second heat can be provided to defrost a first heat exchanger in the heat pump.

It is particularly advantageous if the small storage tank is arranged parallel to the first heating circuit and the second heating circuit connection. This ensures that the warm heat fluid flows safely through the small storage tank even when the first heating circuit is closed and/or slightly open.

In a further embodiment, the small storage unit is arranged in series between the first heating circuit connection and the first secondary side of the first heat exchanger. In this case, the small storage unit can be connected upstream of the first heating circuit connection in relation to a conveying direction of the heat fluid. This design has the advantage that the heat fluid has to flow through the small storage unit on the way to the first heating circuit connection and the small storage unit is therefore filled with warm heat fluid at an early stage. This design has the advantage that when defrosting the second heat exchanger, sufficient second heat can also be provided very early by the small storage unit in order to avoid cooling down the building on the one hand, but at the same time to ensure reliable defrosting of the second heat exchanger.

In a further embodiment, at least one first secondary circuit pump is arranged between the small storage tank and the first heating circuit connection. The first secondary circuit pump is designed to convey the heat fluid between the small storage tank and the first heating circuit connection. This design has the advantage that sufficient pressure for the heat fluid can be provided at the first heating circuit connection. This ensures a sufficiently high mass flow of the heat fluid to the heating system via the first heating circuit when the heating device is installed in the building.

In a further embodiment, the heat fluid transport device has an overflow valve, wherein the overflow valve has a closed position and an open position. The overflow valve is switched to the closed position when a predefined opening pressure on the overflow valve is undershot.

The overflow valve is switched to the open position when the predefined opening pressure on the overflow valve is exceeded. The overflow valve is arranged parallel to the first heating circuit connection and the second heating circuit connection. This design ensures that a sufficient flow of heat fluid is ensured even when the first heating circuit is closed or only slightly open within the heat fluid transport device, so that the small storage tank is reliably filled with warm heat fluid. This design is particularly suitable when the small storage tank is connected in series upstream of the first heating circuit connection and the overflow valve.

In a further embodiment, the heating device has a hot water storage tank with a storage tank and a hot water heat exchanger arranged in the storage tank. The storage tank is designed to store hot water. The heat fluid transport device has a three-way valve, wherein a first valve connection of the three-way valve is fluidically connected to the second heating circuit connection and a second valve connection of the three-way valve is fluidically connected to the primary circuit pump. A first side of the hot water heat exchanger is fluidically connected to a first branch arranged between the first secondary side and the small storage tank. A second side of the hot water heat exchanger is fluidically connected to a third valve connection of the three-way valve. The three-way valve has a first valve position and at least one second valve position that is different from the first valve position. In the first valve position, the three-way valve fluidically connects the second heating circuit connection to the primary circuit pump. In the second valve position, the three-way valve fluidically connects the second side of the hot water heat exchanger with the primary circuit pump. This design has the advantage that, if the small storage tank and the first heating circuit cannot provide sufficient heat to defrost the second heat exchanger of the heat pump, a second portion of the second heat can be taken from the hot water storage tank by adjusting the three-way valve from the first valve position to the second valve position in order to defrost the second heat exchanger.

In a further embodiment, the small storage unit has a first storage connection and a second storage connection, wherein the first storage connection is connected between the first branch and the first heating circuit connection. The second storage connection is connected between the second heating circuit connection and the three-way valve. This design has the advantage that a circulating volume of the heat fluid is particularly large in the first valve position and thus a particularly large amount of second heat can be provided for defrosting the second heat exchanger.

In a further embodiment, the small storage tank has a first storage connection and a second storage connection, the first storage connection being fluidically connected to the first branch and the second storage connection being fluidically connected to the first heating circuit connection, the small storage tank fluidically connecting the first branch to the first heating circuit connection. This ensures early heating of the small storage tank, so that if early defrosting is necessary under unfavorable environmental conditions, for example after heating the water in the hot water tank, sufficient second heat can be extracted from the small storage tank, even if the first heating circuit is not yet essentially fully heated, for example.

In a further embodiment, the heating device has an external unit and an internal unit, wherein the heat pump is arranged in the external unit and has at least one second heat exchanger, wherein the second heat exchanger is fluidically connected to the first heat exchanger for heat exchange. The heat fluid transport device and the small storage unit are arranged in the internal unit. This design ensures that the external unit can be designed to be particularly compact and at the same time that reliable defrosting is ensured.

In a further embodiment, the heating device has a fluid line for guiding the heat fluid, wherein the fluid line has at least one curved section. The curved section encloses at least an angle of at least 45°, preferably at least 90°. The fluid line has at least one plastic and is preformed. Preferably, the fluid line is arranged stress-free or with low stress. This means that the fluid line can be routed at a particularly short distance. Furthermore, geometries that cannot be produced with conventional copper pipes to form the fluid line are possible using the fluid line made of preformed plastic.

It has been recognized that an improved heating system can be provided in that the heating system has a heating device and at least one first heating circuit. The heating device is designed as described above. The first heating circuit is connected to the first heating circuit connection and to the second heating circuit connection and is filled with the heat fluid. The primary circuit pump is designed to guide the heat fluid between the small storage tank and the first secondary side of the first heat exchanger.

A particularly advantageous method for defrosting a heating device with a heat pump, a hot water tank and a heat fluid transport device can be provided in that the heat pump has a compressor integrated into a coolant circuit, a first heat exchanger and a second heat exchanger. A heating mode and a defrosting mode can be provided for operating the heating device. In heating mode, the coolant circuit is operated in a normal direction, with a first heat being absorbed by the second heat exchanger and at least partially transferred to the coolant. The first heat is absorbed by the coolant from the first heat exchanger and transferred to the heat fluid to heat the heat fluid. In a defrosting mode, the heat pump is operated against the normal direction to specifically heat the second heat exchanger. A primary circuit pump of the heat fluid transport device is activated and the heated heat fluid is conveyed to the first heat exchanger. The second heat is transferred from the heat fluid to the coolant, whereby the coolant circulates in the coolant circuit against its normal direction and whereby the coolant transfers the second heat to the second heat exchanger. The second heat is used to defrost the second heat exchanger. When a predefined operating parameter of the heating device is reached, in particular a temperature of the heat fluid, the heat fluid is passed through the hot water tank and the second heat is at least partially taken from the hot water tank. This design has the advantage that reliable de-icing is ensured even in unfavorable weather conditions.

In a further embodiment, in defrosting mode, before the predefined operating parameters are reached, the heat fluid is conveyed from a small storage unit of the heat fluid transport device to the first heat exchanger. The second heat for defrosting the second heat exchanger is transferred from the heat fluid stored in the small storage unit to the first heat exchanger. This embodiment has the advantage that the heating system can be operated particularly comfortably.

In a further embodiment, in the heating mode, the primary circuit pump is controlled such that the heat fluid has a pressure that is greater than an opening pressure of an overflow valve of the heat fluid transport device.

Fig. 1

eine schematische Darstellung eines Heizsystems gemäß einer ersten Ausführungsform;

Fig. 2

ein Ablaufdiagramm eines Verfahrens zum Betrieb des in Fig. 1 gezeigten Heizsystems;

Fig. 3

eine schematische Darstellung eines Heizsystems gemäß einer zweiten Ausführungsform;

Fig. 4

eine schematische Darstellung eines Heizsystems gemäß einer nicht von der Erfindung umfassten dritten Ausführungsform;

Fig. 5

eine schematische Darstellung eines Heizsystems gemäß einer vierten Ausführungsform;

Fig. 6

eine perspektivische Darstellung einer Heizeinrichtung eines Heizsystems gemäß einer fünften Ausführungsform;

Fig. 7

einen in Fig. 6 markierten Ausschnitt A des in Fig. 6 gezeigten Heizsystems; und

Fig. 8 und Fig. 9

Draufsichten auf einen in Fig. 6 markierten Ausschnitt B.

The invention is explained below using figures.

Fig. 1

a schematic representation of a heating system according to a first embodiment;

Fig. 2

a flow chart of a method for operating the Fig. 1 heating system shown;

Fig. 3

a schematic representation of a heating system according to a second embodiment;

Fig. 4

a schematic representation of a heating system according to a third embodiment not covered by the invention;

Fig. 5

a schematic representation of a heating system according to a fourth embodiment;

Fig. 6

a perspective view of a heating device of a heating system according to a fifth embodiment;

Fig. 7

one in Fig. 6 marked section A of the Fig. 6 heating system shown; and

Fig. 8 and Fig. 9

Top views of a Fig. 6 marked section B.

Fig. 1 shows a schematic representation of a heating system 10 according to a first embodiment.

The heating system 10 has a heating device 15, at least one first heating circuit 20 and a water supply device 25. The first heating circuit 20 can, for example, have one or more radiators. The water supply device 25 can, for example, have one or more water pipes for supplying the heating device 15 and the building with water, in particular drinking water.

The heating device 15 is designed as an air-water heat pump in the embodiment. The heating device 15 has a heat pump 30, a heat fluid transport device 35 and preferably a hot water tank 40. In the embodiment, for example, the heating device 15 is divided into an external unit 45 and an internal unit 50. The external unit 45 can be arranged outside the building. For example, the external unit 45 can be designed as an outdoor installation device. The external unit 45 can also be arranged in the building and be fluidly connected to the environment 405 of the building, for example via a fresh air duct.

The indoor unit 50 can, for example, be designed as an indoor installation device and is arranged in the building. A multi-part design of the indoor unit 50 can also be provided. In particular, the integration of the hot water tank 40 in the indoor unit 50 can be dispensed with and, for example, the hot water tank 40 can be installed next to the indoor unit 50.

The hot water tank 40 has, for example, a fresh water connection 55 and a hot water connection 60. The hot water tank 40 also has a storage tank 65 and a hot water heat exchanger 70 arranged in the storage tank 65. In addition, the hot water tank 40 can have a circulation connection 75. The circulation connection 75 can also be omitted. The fresh water connection 55 can, for example, be fluidically connected to a fresh water network, in particular a drinking water network. Furthermore, the fresh water connection 55 is connected to the storage tank 65 by means of a fresh water line 80. The storage tank 65 is thermally insulated and stores hot water when the heating system 10 is in operation. The hot water connection 60 is in turn fluidically connected to the storage tank 65 by means of a hot water line 85. The water supply device 25 is connected to the fresh water connection 55 and the hot water connection 60 in order to fluidly connect a withdrawal point 76 to the hot water tank 40.

The heat pump 30 has a first heat exchanger 90, a second heat exchanger 95, a refrigerant circuit 100 as well as a compressor 105 and an expansion valve 110. The refrigerant circuit 100 is filled with a refrigerant 115. The refrigerant 115 can be, for example, R410 or R290.

The first heat exchanger 90 has a first primary side and a first secondary side 120, wherein the first primary side of the first heat exchanger 90, the expansion valve 110, a second secondary side of the second heat exchanger 95 and the compressor 105 are integrated into the refrigerant circuit 100.

The thermal fluid transport device 35 has at least one primary circuit pump 125, preferably an electric auxiliary heater 130, a small storage tank 135, preferably a first secondary circuit pump 140, a three-way valve 145, a first heating circuit connection 150 and at least one second heating circuit connection 155. In addition, the thermal fluid transport device 35 can have an expansion vessel 160 and/or optionally a safety valve 165.

The thermal fluid transport device 35 is filled with a thermal fluid 170. The thermal fluid 170 can, for example, contain water and, if appropriate, an additive, in particular an antifreeze. The thermal fluid 170 is preferably present in the liquid state in the thermal fluid transport device 35.

The primary circuit pump 125 has a first inlet side and a first outlet side. The first outlet side of the primary circuit pump 125 is fluidically connected to the first secondary side 120 of the first heat exchanger 90 by means of a first fluid line 175. On the outlet side of the first heat exchanger 90, the first secondary side 120 is connected to the electric auxiliary heater 130, for example via a second fluid line 180. The electric auxiliary heater 130 is connected to a first branch 190 on a side facing away from the second fluid line 180 via a third fluid line 185. A fourth fluid line 195 is connected to the first branch 190, which connects a first side 200 of the hot water heat exchanger 70 to the first branch 190. A fifth fluid line 205 fluidically connects the first branch 190 with a second branch 210. Both the first branch 190 and the second branch 210 can be designed as a T-branch, for example.

The small storage unit 135 has a first storage connection 215 and a second storage connection 220. The second storage connection 220 is arranged opposite the first storage connection 215. A storage container 225 of the small storage unit 135 extends between the first storage connection 215 and the second storage connection 220. The storage container 225 is thermally insulated and has a significantly smaller capacity for temporarily storing the heat fluid 170 than the storage tank 65. For example, the storage tank 65 can have a volume of 150 to 300 liters, while the storage container 225 has a volume of 15 to 25 liters, preferably 15 to 20 liters. The small storage unit 135 can be designed, for example, as a solar pre-heating vessel. The storage container 225 connects the first storage connection 215 to the second storage connection 220. The storage container 225 is designed such that a quasi-short circuit between the first storage connection 215 and the second storage connection 220 is avoided. In particular, the storage container 225 can, for example, be designed like a tube, with the storage connection 215, 220 being arranged at one end of the storage container 225.

The first storage connection 215 is connected to the second branch 210 by means of a sixth fluid line 230. Furthermore, the second branch 210 is connected to a second input side of the first secondary circuit pump 140 by means of a seventh fluid line 235 on a side opposite the fifth fluid line 205. The second branch 210 is thus arranged directly upstream of the first secondary circuit pump 140 and the first branch 190 is arranged upstream of the second branch 210. Downstream of the first secondary circuit pump 140, the first secondary circuit pump 140 is connected on its second output side to the first heating circuit connection 150 by means of an eighth fluid line 240. The first heating circuit 20 is connected, for example, on one side to the first heating circuit connection 150 and on the other side to the second heating circuit connection 155. For example, the first heating circuit connection 150 can form a flow connection for the first heating circuit 20 and the second heating circuit connection 155 can form a return connection for the first heating circuit 20.

The second heating circuit connection 155 is connected to a first junction 250 by means of a ninth fluid line 245. The first junction 250 can, for example, be T-shaped. A tenth fluid line 255 is connected to the first junction 250, which fluidically connects the first junction 250 to the second storage connection 220.

The three-way valve 145 has a first valve connection 260, a second valve connection 265 and a third valve connection 270. The first valve connection 260 is fluidically connected to the first junction 250 by means of an eleventh fluid line 275. A twelfth fluid line 280 fluidically connects the first input side of the primary circuit pump 125 to the second valve connection 265 of the three-way valve 145. Furthermore, a thirteenth fluid line 285 is connected to the third valve connection 270, which has a second Side 290 of the hot water heat exchanger 70 is fluidically connected to the third valve connection 270.

Optionally, for example, the safety valve 165 can be connected to the twelfth fluid line 280 downstream of the second valve connection 265. Furthermore, the expansion vessel 160 can be connected to the twelfth fluid line 280, for example, fluidically between the safety valve 165 and the first inlet side of the primary circuit pump 125.

The control system 39 comprises, for example, a control unit 300, an outside temperature sensor 305, a first temperature sensor 310, preferably a second temperature sensor 315, a pressure sensor 320 and/or a storage temperature sensor 330.

The control unit 300 has a data memory 335, a control device 340 and an interface 345. The data memory 335 is connected to the control device 340 by means of a first connection 346. Furthermore, the control device 340 is connected to the interface 345 by means of a second connection 347.

At least one predefined operating parameter is stored in the data memory 335, for example. Furthermore, a predefined control algorithm, which is designed as a computer program, for example, can be stored in the data memory 335. Furthermore, a first to third predefined temperature threshold value S1, S2, S3, a predefined heating curve and a predefined maximum permissible icing state are stored in the data memory. The predefined second temperature threshold value S2 can be the predefined operating parameter.

The outside temperature sensor 305 measures an outside temperature TA. The first temperature sensor 310 is arranged, for example, on the seventh fluid line 235 and measures a first temperature T1 of the heat fluid 170 upstream of the second inlet side of the first secondary circuit pump 140. The second temperature sensor 315 is arranged on the outlet side of the first heat exchanger 90 and measures a second temperature T2 of the heat fluid 170 in the third fluid line 185. The pressure sensor 320 is arranged in the refrigerant circuit 100 and measures a pressure of the refrigerant 115.

The interface 345 is connected to the outside temperature sensor 305 by means of a third connection 350. Furthermore, the interface 345 is connected to the compressor 105 via a fourth connection 355. A fifth connection 360 connects the three-way valve 145 to the interface 345. A sixth connection 365 connects the interface 345 to the primary circuit pump 125 and a seventh connection 370 connects the first secondary circuit pump 140 to the interface 345. An eighth to eleventh connection 375 to 395 connects the first temperature sensor 310 and second temperature sensor 315 as well as the storage temperature sensor 330 to the interface 345.

The connection 346, 347, 350, 355, 360, 365, 370, 375, 380, 385, 395 can be designed both wirelessly and with a wire. Furthermore, the first to eleventh connections 346, 347, 350, 355, 360, 365, 370, 375, 380, 385, 395 can be part of a bus system, in particular, for example, a Modbus system. Another design of the first to eleventh connections would also be possible.

It is also pointed out that the number of temperature sensors 310, 315, 330 and the connections 346, 347, 350, 355, 360, 365, 370, 375, 380, 385, 395 are exemplary. Another design of the control system 39 would also be possible.

In Fig. 1 the connection 346, 347, 350, 355, 360, 365, 370, 375, 380, 385, 395 is shown by dashed lines as an example to make it easier to distinguish it from the fluid lines 175, 180, 185, 195, 205, 230, 235, 240, 245, 255, 275, 280, 285, 435, 445, 455. A data/control signal with information can be transmitted, for example, using the connection 346, 347, 350, 355, 360, 365, 370, 375, 380, 385, 395. The data/control signal can be transmitted digitally or analogously.

The three-way valve 145 has a first valve position and a second valve position that is different from the first valve position. In the first valve position the three-way valve 145 connects the eleventh fluid line 275 to the twelfth fluid line 280, so that the second storage connection 220 is connected to the first input side of the primary circuit pump 125 via the tenth fluid line 255 and the first junction 250. Likewise, in the first valve position, the second heating circuit connection 155 is fluidically connected to the first input side of the primary circuit pump 125 via the ninth fluid line 245, the first junction 250 and the eleventh fluid line 275 by means of the twelfth fluid line 280.

In the second valve position of the three-way valve 145, the eleventh fluid line 275 is fluidically decoupled from the twelfth fluid line 280, so that both the second heating circuit connection 155 and the second storage connection 220 are fluidically separated from the twelfth fluid line 280 and thus the first input side of the primary circuit pump 125. In the second valve position, the thirteenth fluid line 285, which fluidically connects the second side 290 of the hot water heat exchanger 70 to the third valve connection 270, is fluidically connected to the twelfth fluid line 280, so that the second side 290 of the hot water heat exchanger 70 is fluidically continuously connected to the first input side of the primary circuit pump 125 via the three-way valve 145.

In the embodiment, the three-way valve 145 is switched such that the three-way valve 145 takes up either the first valve position or the second valve position. The first valve position thus forms the alternative to the second valve position. In a further development, the three-way valve 145 can also be designed as a mixing valve which, in a mixing position, takes up both the first valve position and the second valve position and fluidically connects both the second side 290 of the hot water heat exchanger 70 to the first input side of the primary circuit pump 125 and the second heating circuit connection 155 and the second storage connection 220 to the first input side of the primary circuit pump 125.

Fig. 2 shows a flow chart of a method for operating the Fig. 1 shown heating system 10.

The heating system 10 has at least two, preferably three, operating states as described in the embodiment below.

In a first operating state, which can also be referred to as the first heating mode, the heating system 10 heats the heating circuit 20 in order to heat a room in a building. In a second operating state, which can also be referred to as the second heating mode, fresh water introduced into the storage tank 65 is heated and, in the heated state, is provided as hot water via the water supply device 25, for example at the extraction point 76.

In a third operating mode, the second heat exchanger 95 is defrosted in a defrosting mode to ensure the functionality of the heat pump 30 for heating the heat fluid 170. The icing of the second heat exchanger 95 occurs primarily in the case of high air humidity in conjunction with an outside temperature around freezing point.

Before the method described below is carried out, the first temperature sensor 310 on the inlet side of the first secondary circuit pump 140 measures the first temperature T1 of the heat fluid 170. Furthermore, the outside temperature sensor 305 measures the outside temperature TA. The control device 340 takes the first temperature T1 and the outside temperature into account when controlling the compressor 105 and the primary circuit pump 125 as well as the first secondary circuit pump 140.

Based on the outside temperature TA and the heating curve, which can be set by the customer on the device, a setpoint value for the first temperature T1 is determined. If the measured value of the first temperature T1 is less than the setpoint value, the control device 340 detects a heat requirement for the first heating circuit 20.

In a first method step 505, the heating device 15 is switched to the first heating mode. The control device 340 activates the compressor 105 and the compressor 105 conveys the coolant 115 in the coolant circuit 100 in a normal direction. In this case, a first heat Qi is taken from the environment 405 by a source medium, for example from fresh air conveyed to the second heat exchanger 95. The first heat Qi is transferred from the second heat exchanger 95 via the coolant circuit 100 to the first primary side of the first heat exchanger 90. In the first heat exchanger 90, the first heat Qi is at least partially transferred from the coolant 115 to the heat fluid 170 and the heat fluid 170 is heated. Furthermore, in the first operating state, the primary circuit pump 125 is activated so that the primary circuit pump 125 conveys the heat fluid 170. The heat fluid 170 is conveyed from the first secondary side 120 of the first heat exchanger 90 via the second fluid line 180 to the electric auxiliary heater 130. In the first operating state, the electric auxiliary heater 130 is deactivated, for example. The heat fluid 170 flows through the electric auxiliary heater 130 and the third fluid line 185 up to the first branch 190. In the first operating state, the three-way valve 145 is switched to the first valve position by the control device 340, so that the heat fluid 170 essentially flows into the fifth fluid line 205 at the first branch 190. The heat fluid 170 flows towards the second branch 210. In the first operating state, the first heating circuit 20 is open, for example. The control device 340 preferably controls the first secondary circuit pump 140 in such a way that a delivery capacity of the first secondary circuit pump 140 is lower than a delivery capacity of the primary circuit pump 125. This has the consequence that at the second branch 210 a mass flow of the heat fluid 170 is divided between the sixth fluid line 230 and the seventh fluid line 235. It is particularly advantageous if the delivery capacity of the primary circuit pump 125 is approximately 5 to 10% greater than the delivery capacity of the first secondary circuit pump 140.

A first part of the heat fluid 170 flows via the seventh fluid line 235 to the first secondary circuit pump 140, which conveys the first part via the first heating circuit connection 150 into the first heating circuit 20. After heating the building, the first part exits the first heating circuit 20 in a cooled state via the second heating circuit connection 155 into the heat fluid transport device 35 and flows via the ninth fluid line 245 to the first junction 250.

A second part of the heat fluid 170 flows into the sixth fluid line 230 and enters the storage tank 225 at the first storage connection 215. The storage tank 225 can be designed like a tube, for example. The incoming heated heat fluid 170 flows through the storage tank 225, and an already cooled heat fluid 170 is led from the storage tank 225 of the small storage tank 135 via the second storage connection 220. During the conveyance of the heat fluid 170 of the primary circuit pump 125, the heat fluid 170 stored in the storage tank 225 is thus successively exchanged, so that after a predefined first time interval the storage tank 225 of the small storage tank 135 is filled with warm heat fluid 170. As long as the primary circuit pump 125 is activated, the warm heat fluid 170 continues to be guided through the storage tank 225 with the second part and flows continuously through the storage tank. The warm heat fluid 170 flows via the second storage connection 220 to the first junction 250.

Due to the arrangement of the small storage tank 135 fluidically between the first heating circuit connection 150 and the second heating circuit connection 155, the small storage tank 135 is thus hydraulically connected in parallel to the first heating circuit connection 150 and the second heating circuit connection 155 as well as the first heating circuit 20.

At the first junction 250, the first part of the heat fluid 170 and the second part of the heat fluid 170 are brought together and guided via the eleventh fluid line 275 to the three-way valve 145. By switching the three-way valve 145 to the first valve position, the heat fluid 170 flows via the first fluid line 175 to the twelfth fluid line 280 and back to the first inlet side of the primary circuit pump 125. The primary circuit pump 125 again pumps the heat fluid 170 from the twelfth fluid line 280 in the circuit into the first fluid line 175, which guides the heat fluid 170 into the first secondary side 120 of the first heat exchanger 90.

In summary, in the first valve position, preferably only the first heating circuit 20 is supplied with the first heat Qi. The first heat Qi can then be transferred to the building in the first heating circuit 20 in order to heat the building.

In a second method step 510, the storage temperature sensor 330 measures the water temperature TW of the hot water stored in the storage tank 65. The second method step 510 can take place in parallel to the first method step 505.

In a third method step 515 following the second method step 510, the control device 340 compares the detected water temperature TW with the predefined first temperature threshold value S1. If the determined hot water temperature TW falls below the predefined first temperature threshold value S1, the process continues with a fourth method step 520. If the hot water temperature TW exceeds the predefined first temperature threshold value S1, the process continues with a fifth method step 525.

It is pointed out that the second and third method steps 510, 515 can also be carried out before the first method step 505, in particular if prioritization of the hot water tank 40 is desired.

In the fourth method step 520, the control device 340 switches the three-way valve 145 into the second valve position by means of a control signal via the fifth connection 360. Furthermore, the control device 340 can deactivate the first secondary circuit pump 140. The control device 340 can also continue to switch the first secondary circuit pump 140 to active.

At the first branch 190, the warm heat fluid 170 flows into the fourth fluid line 195 towards the first side 200 of the hot water heat exchanger 70. The warm heat fluid 170 flows through the hot water heat exchanger 70 from the first side 200 towards the second side 290. With the first heat Qi, the warm heat fluid 170 heats the (cold) fresh water/hot water present in the storage tank 65 to hot water.

In addition, a running time of the compressor 105 can be determined in the first method step 505 and/or in the fourth method step 520. The determined Running time can be compared with a predefined minimum running time of the compressor 105, whereby if the minimum running time is not reached, the first method step 505 or the fourth method step 520 is continued until the minimum running time is reached.

In a fifth method step 525, the control device 340 switches the three-way valve 145 to the first valve position or the three-way valve 145 remains in the first valve position.

During the first to fifth method steps 505 to 525, when the outside temperature is low, moisture can condense on the second heat exchanger 95 and the condensate can freeze the second heat exchanger 95.

In a sixth method step 530 following the fourth and fifth method steps 520, 525, the pressure sensor 320 determines an evaporation pressure p. Furthermore, on the basis of this measurement and the thermophysical material data of the refrigerant 115, a current evaporation temperature TVD is calculated in the control device 340. On the basis of the outside temperature TA and the pressure p or the temperature TVD, the control device 340 determines an icing condition on the primary side of the second heat exchanger 95. In addition, a further temperature sensor (not in Fig. 1 shown) in order to determine the icing condition particularly well.

In a seventh method step 535 following the sixth method step, the control device 340 checks whether the second heat exchanger 95 is excessively iced up on the primary side or whether the icing is within a permissible range by comparing the determined reference state with a predefined maximum permissible icing state. If the control device 340 detects that the second heat exchanger 95 is more iced up than the predefined maximum permissible icing state, the control device 340 continues with an eighth method step 540. If the icing of the second heat exchanger 95 is below the predefined maximum permissible icing state, the control device 340 continues with the first method step 505. if the water temperature TW is greater than the first predefined temperature threshold value S1 (cf. fifth method step 525), or with the fourth method step 520 if the water temperature TW is less than the first predefined temperature threshold value S1.

In the eighth method step 540, the conveyance of the refrigerant 115 is reversed from the normal direction in the refrigerant circuit 100 by a corresponding switching of the refrigerant circuit 100 and the refrigerant circuit 100 is switched in the cooling direction. As a result, the refrigerant 115 in the first heat exchanger 90 absorbs a second heat Q̇ ₂ from the heat fluid 170 and transfers it to the second heat exchanger 95. The heat fluid 170 is cooled in the first heat exchanger 90. The second heat Q̇ ₂ is used to defrost the second heat exchanger 95 on the primary side.

In order to provide a sufficiently large amount of second heat Q̇ ₂ , in the eighth method step 540 the three-way valve 145 is set to the first valve position by the control device 340. Furthermore, the control device 340 activates the primary circuit pump 125 and the first secondary circuit pump 140 in order to convey both the heat fluid 170 from the first heating circuit 20 and from the small storage tank 135 to the first secondary side 120 of the first heat exchanger 90.

The cooled heat fluid 170 is introduced into the second fluid line 180 in a cold state. The heat fluid 170 circulates between the small storage tank 135 and the first heating circuit 20 as well as the first heat exchanger 90. In a ninth method step 545, the second temperature sensor 315 measures the second temperature T2 of the heat fluid 170 on the outlet side of the first heat exchanger 90.

In a tenth method step 550 following the ninth method step 545, the control device 340 compares the second temperature T2 with the predefined second temperature threshold value S2. If the second temperature T2 falls below the predefined second temperature threshold value S2, the control device 340 continues with an eleventh method step 555.

If the second temperature T2 exceeds the predefined second temperature threshold value S2, the control device 340 proceeds to the eighth method step 540.

The control device 340 continuously carries out the sixth and seventh method steps 530, 535 in parallel to the ninth method step 545 to check whether the second heat exchanger 95 has now defrosted sufficiently. If the control device 340 detects that the second heat exchanger 95 has defrosted, the control device ends the defrosting mode. Depending on the current requirement (heating or hot water or no requirement), the control device 340 switches the heat pump 30 to the first or second heating mode or to a standby mode.

In the eleventh method step 555, the control device 340 controls the three-way valve 145 such that the three-way valve 145 is switched from the first valve position to the second valve position. Furthermore, the control device 340 can deactivate the first secondary circuit pump 140 in order to avoid feeding the first heating circuit 20 with cold heat fluid 170. However, the first secondary circuit pump 140 can also continue to operate. The primary circuit pump 125 remains activated. By activating the primary circuit pump 125, the heat fluid 170 is now introduced in a cooled state via the first side 200 into the storage tank 65 with hot water. The hot water of the storage tank 65 heats the heat fluid 170 with the second heat Q̇ ₂ , so that the heat fluid 170 is guided in a warm state via the second side 290 and the thirteenth fluid line 285 to the three-way valve 145. The primary circuit pump 125 conveys the heat fluid 170 via the first fluid line 175 into the first heat exchanger 90. In the first heat exchanger 90, the second heat Q̇ ₂ is transferred from the heat fluid 170 to the coolant 115. The coolant 115 circulating in the opposite direction transfers the second heat Q̇ ₂ to the second heat exchanger 95. The second heat Q̇ ₂ is then used to defrost the second heat exchanger 95.

The control device 340 continuously carries out the sixth and seventh method steps 530, 535 in parallel to the eleventh method step 555 to check whether the second heat exchanger 95 has now defrosted sufficiently.

Furthermore, in the ninth and eleventh method steps 545, 555, a minimum running time of the compressor 105 is detected by the control device 340. If the minimum running time is not reached, the ninth or eleventh method steps 545, 555 are carried out until the minimum running time is reached.

If the control device 340 detects that the second heat exchanger 95 has defrosted, the control device 340 ends the defrosting mode. Depending on the current requirement (heating or hot water or no requirement), the control device 340 switches the heating device 15 to the first or second heating mode or to a standby mode.

Parallel to the eleventh method step 555, the storage temperature sensor 330 determines the water temperature TW of the hot water in the storage tank 65 in a twelfth method step 560.

In a thirteenth method step 565, which follows the twelfth method step 560, the control device 340 compares the hot water temperature TW with the predefined third temperature threshold value S3. The third temperature threshold value S3 may be lower than the first temperature threshold value S1 and higher than the second temperature threshold value S2. If the water temperature TW falls below the third predefined temperature threshold value S3, the control device 340 continues with the fourteenth method step 570. If the hot water temperature TW exceeds the predefined temperature threshold value S3, the control device 340 continues with the eleventh method step 555.

In the fourteenth method step 570, the control device 340 activates the electric auxiliary heater 130, wherein the control device 340 can use the first temperature threshold value S1 as the setpoint for the hot water in the storage tank 65 as a reference variable for controlling the electric auxiliary heater 130.

The control device 340 continuously carries out the sixth and seventh method steps 530, 535 parallel to the fourteenth method step 570 for Check whether the second heat exchanger 95 has now defrosted sufficiently. If the control device 340 detects that the second heat exchanger 95 has defrosted, the control device ends the defrosting mode. Depending on the current requirement (heating or hot water or no requirement), the control device 340 switches the heating device to the first or second heating mode or to a standby mode.

The method described above and the heating system 10 have the advantage that the parallel arrangement of the small storage tank 135 ensures a minimum volume flow in the first method step 505, regardless of whether the first heating circuit 20 is open or closed. By controlling the primary circuit pump 125, the first secondary circuit pump 140 and the heat pump 30, a predefined target flow temperature of the heat fluid 170 at the first temperature sensor 310 is reliably ensured, so that the small storage tank 135 is filled with warm heat fluid in particular.

The volume of the small storage tank 135 is selected such that the compressor 105 can be operated at least for the minimum running time in the first process step 505 even when the first heating circuit 20 is closed. This ensures a long service life of the compressor 105.

Furthermore, the small storage tank 135 ensures that the second heat exchanger 95 can be defrosted in the eighth process step 540 in the vast majority of cases and that the eleventh to fourteenth process steps 555, 560, 565, 570 are only carried out in exceptional cases.

Fig. 3 shows a schematic representation of a heating system 10 according to a second embodiment.

The heating system 10 is essentially identical to that in Fig. 1 The following will focus exclusively on the differences between the heating system 10 shown in Fig. 3 shown heating system 10 compared to the one in the Figures 1 and 2 The heating system 10 shown is discussed.

In addition to the first heating circuit 20, the heating system 10 has a second heating circuit 410. In addition, the heat fluid transport device 35 has a third heating circuit connection 415 and a fourth heating circuit connection 420 in addition to the first heating circuit connection 150 and the second heating circuit connection 155. The third heating circuit connection 415 and the fourth heating circuit connection 420 are connected to the second heating circuit 410 in such a way that the second heating circuit 410 is connected on the flow side to the third heating circuit connection 415 and on the return side to the fourth heating circuit connection 420.

In addition, to control the second heating circuit 410, which can be designed as underfloor heating in the building, for example, the heat fluid transport device 35 can have a mixing valve 425 and a second secondary circuit pump 430. The mixing valve 425 is connected on the inlet side via a fourteenth fluid line 435 to a third branch 440, wherein the third branch 440 is built into the seventh fluid line 235. On the outlet side, the mixing valve 425 is connected to a third inlet side of the second secondary circuit pump 430 via a fifteenth fluid line 445. Furthermore, the mixing valve 425 is connected to a bypass 450, which is guided parallel to the third and fourth heating circuit connections 415, 420. The bypass 450 and the fourth heating circuit connection 420 are connected to the ninth fluid line 245 at a second junction 460 via a sixteenth fluid line 455. Due to this configuration of the heat fluid transport device 35, the second heating circuit 410 is designed as a mixed heating circuit, whereas the first heating circuit 20 is unmixed.

The method for operating the heating system 10 may be substantially identical to that described in Fig. 2 explained methods. In the following, only the differences are discussed. During defrosting, in the eighth method step 540, in addition to the first secondary circuit pump 140, the second secondary circuit pump 430 is also activated and the mixing valve 425 is set by the control device 340 in such a way that a backflow from the fifteenth fluid line 445 via the bypass 450 to the mixing valve 425 is avoided. The heat fluid 170 thus flows not only through the first heating circuit 20, but also the second heating circuit 410 and is supplied by the first and second Heating circuit 20, 410 is introduced into the ninth fluid line 245 via the second junction 460 and from there is led in the direction of the first and second heat exchangers 90, 95 for defrosting the second heat exchanger 95.

In the eleventh method step 555, in addition to the first secondary circuit pump 140, the second secondary circuit pump 430 is also deactivated.

Fig. 4 shows a schematic representation of a heating system 10 according to a third embodiment not covered by the invention.

The heating system 10 is essentially identical to that in Figure 1 The following will focus exclusively on the differences between the heating system 10 Fig. 4 shown heating system 10 compared to the one in the Figure 1 shown heating system 10. In Fig. 4 is compared Fig. 3 the second heating circuit 410 and the corresponding extension of the heat fluid transport device 35 are dispensed with.

Furthermore, the small storage unit 135 is particularly thin in the embodiment and can be designed as a tube, for example. In contrast to the parallel connection of the small storage unit 135 in Figures 1 and 3 parallel to the first and second heating circuit connections 150, 155, arranged serially between the first branch 190 and the first heating circuit connection 150.

In Fig. 4 the first secondary circuit pump 140 is omitted. In this case, the primary circuit pump 125 also serves to supply the first heating circuit 20 with heat fluid 170. This design has the advantage that the first heating circuit 20 is fluidically coupled directly to the first heat exchanger 90. This makes the heating system 10 particularly simple and cost-effective.

The small storage tank 135 is arranged in fluidic series between the first branch 190 and the second branch 210. An overflow valve 465 is arranged on the second branch 210 parallel to the first heating circuit connection 150 and the second heating circuit connection 155. The overflow valve 465 can be adjustable or non-adjustable. The overflow valve 465 has a closed position and an open position, wherein in an open position the overflow valve 465 fluidically connects the second branch 210 to the first junction 250. In the closed position, the overflow valve 465 fluidically separates the second branch 210 from the first junction 250. The overflow valve 465 is in the closed position below a predefined opening pressure on the inlet side of the overflow valve 465. If a pressure of the thermal fluid 170 on the inlet side adjacent to the overflow valve 465 exceeds the opening pressure, the overflow valve 465 is switched to the open position so that the thermal fluid 170 overflows from the second branch 210 via the overflow valve 465 to the first junction 250.

The overflow valve 465 can be designed in different ways. For example, it can be controlled to open electronically by the control device 340. It would also be possible for the overflow valve 465 to be spring-loaded. The overflow valve 465 can be adjustable or designed with a fixed opening pressure.

It is particularly advantageous if the specified opening pressure is fixed, as this avoids a source of error when installing the heating system 10. The opening pressure is greater than a residual delivery head for the connected first heating circuit 20.

By integrating the overflow valve 465 and the small storage tank 135, the installation effort when installing the heating system 10 in the building is reduced.

The method for defrosting the second heat exchanger 95 is essentially identical to that in Fig. 2 The following will focus exclusively on the differences between the operation of the Fig. 4 showed heating system 10 compared to the Fig. 2 explained procedures.

In the first method step 505, the heat fluid 170 flows through the small storage tank 135 on the way from the first branch 190 to the first heating circuit connection 150. As a result, the small storage tank 135 is filled with particularly warm heat fluid 170 when the primary circuit pump 125 is activated.

If the first heating circuit 20 is closed, for example because the control valves of the first heating circuit 20 are closed or the thermostats are turned off, the flow through the small storage tank 135 is ensured in such a way that the control device 340 controls the primary circuit pump 125 in such a way that the primary circuit pump 125, although the first heating circuit 20 is closed, continues to pump the heat fluid 170 in the direction of the first heat exchanger 90 at least with a low volume flow. Furthermore, the heat pump 30 is activated so that the first heat Qi is transferred to the heat fluid 170 in the first heat exchanger 90 and the heat fluid 170 is heated. The primary circuit pump 125 conveys the heat fluid 170 through the small storage tank 135 via the first branch 190 despite the first heating circuit 20 being switched off or closed. Due to the closed first heating circuit 20 and the conveyance of the heat fluid 170, the pressure of the heat fluid 170 on the inlet side of the overflow valve 465 increases. The control device 340 controls the primary circuit pump 125 in such a way that the pressure on the inlet side of the overflow valve 465 is greater than the opening pressure and the overflow valve 465 changes from the closed position to the open position and the heat fluid 170 flows in the circuit via the overflow valve 465 and the three-way valve 145 to the primary circuit pump 125. This ensures that the small storage tank 135 is filled with warm heat fluid 170.

In the eighth method step 540, as explained in the first method step 505, the control device 340 can control the primary circuit pump 125 in such a way that the pressure of the heat fluid 170 on the inlet side of the overflow valve 465 is greater than the opening pressure of the overflow valve 465. This ensures that the heat fluid 170 stored in the small storage tank 135 can be conveyed via the overflow valve 465 in the direction of the three-way valve 145. Furthermore, the primary circuit pump 125 conveys the warm heat fluid 170 from the small storage tank 135 in the direction of the first heat exchanger 90, in which the second heat Q̇ ₂ in defrosting mode is extracted from the warm Heat fluid 170 is removed and transferred via the refrigerant circuit 100 to the second heat exchanger 95 for defrosting the second heat exchanger 95.

This design has the advantage that sufficient second heat Q̇ ₂ can be made available for defrosting, even if the first heating circuit 20 is closed. In particular, this can minimize a loss of comfort due to the possibly necessary further removal of second heat Q̇ ₂ from the hot water tank 40 in the eleventh method step 555.

Fig. 5 shows a schematic representation of a heating system 10 according to a fourth embodiment.

The heating system 10 is essentially identical to that in Fig. 4 shown heating system 10. Deviating from this, in Fig. 5 The small storage tank 135 is designed with a significantly larger volume than the one in Fig. 4 Small storage tank 135 shown. The one in Fig. 5 The small storage unit 135 shown can, for example, be designed as a solar ballast vessel.

The in Fig. 5 shown serial arrangement with a small storage tank 135 with a significantly larger volume than in Fig. 4 has shown the advantage that even a large second heat exchanger 95 can be reliably defrosted without having to resort to the extraction of second heat Q̇ ₂ from the hot water tank 40 when the first heating circuit 20 is closed.

Fig. 6 shows a perspective view of the heating device 15 of a heating system 10 according to a fifth embodiment.

The heating device 15 is essentially identical to that in Fig. 1 The following will focus exclusively on the differences between the heating device 15 shown in Fig. 6 shown heating system 10 compared to the one in Fig. 1 The heating system 10 shown is discussed.

In the embodiment, the fourth fluid line 195 has, for example, a first section 600 and a second section 605. The second section 605 is formed, for example, from a bent copper tube.

The first section 600 comprises, for example, a plastic as a material and is preformed. For example, the first section 600 can be designed as an arc section that includes at least an angle of at least 45°, preferably of at least 90°. The design of the first section 600 from a preformed plastic line has the advantage that the fourth fluid line 195 is mounted essentially stress-free or at least with little stress. Furthermore, a tolerance compensation between the second section 605 and a storage tank 65 can be achieved essentially stress-free or with little stress.

The design of the first section 600 with a preformed plastic line has the advantage that, compared to a fixed copper pipe connection, a tolerance of several millimeters can be compensated for by the preformed plastic line of the first section 600.

The thirteenth fluid line 285 can be designed analogously to the fourth fluid line 195. In contrast, the thirteenth fluid line 285 is made entirely of a plastic and preformed.

Fig. 7 shows one in Fig. 6 marked section A of the Fig. 6 shown heating system 10.

By designing the thirteenth fluid line 285 from a preformed plastic, the thirteenth fluid line 285 can be guided past the fourth fluid line 195 in the region of the second subsection 605 at a spatially close distance. As a result, the installation space requirement of the heating system 10 is particularly low.

Fig. 8 and Fig. 9 show top views of a Fig. 6 marked section B.

In order to connect the second section 605 to the first section 600, a clamping means 610 is provided in the embodiment. The clamping means 610 can be designed, for example, as a spring clip that surrounds the first section 600 on the circumference and fixes the first section 600 to the second section 605. The first section 600 is plugged onto the second section 605 and fixed in a form-fitting and force-fitting manner by the clamping means 610.

This design has the advantage that the fourth and thirteenth fluid lines 195, 285 can be mounted in a fluid-tight manner in a particularly simple and cost-effective manner. Furthermore, the clamping means 610 can be released reversibly without causing any damage.

In comparison to the second section 605, the first section 600 offers the advantage that bends in the space can be made particularly narrowly and cost-effectively. Furthermore, the first section 600 and the thirteenth fluid line 285 can be produced particularly easily and cost-effectively, for example by thermal deformation for preforming the first section 600 and the thirteenth fluid line 285. Furthermore, geometries can be produced that cannot be produced using a copper tube.

It is pointed out that in the example the preformed plastic line is provided by way of example in the first partial section 600 and in the thirteenth fluid line 285. Of course, at least one of the other fluid lines 175, 180, 185, 195, 205, 230, 235, 240, 245, 255, 275, 280, 435, 445, 455 can be formed by a preformed plastic line, at least in sections.

Claims (13)

1. Heating device (15) for heating a building,
   having a heat pump (30) with a first heat exchanger (90), having a hot-water store (40) for drinking water with a storage tank (65) and with a hot-water heat exchanger (70) arranged in the storage tank, and having a heat-fluid-transport device (35) with a primary-circuit pump (125) and with at least one first heating-circuit connection (150) and with one second heating-circuit connection (155), wherein the heat-fluid-transport device (35) is able to be filled with a heat fluid (170) and is configured to transport and to distribute the heat fluid (170), wherein a first secondary side (120) of the first heat exchanger (90) is connected fluidically to the first and/or second heating-circuit connection (150, 155), characterized in that, in addition to the hot-water store (40), the heat-fluid-transport device (35) has a small store (135) with a storage container (225) for intermediate storage of the heat fluid (170), wherein the storage container is thermally insulated and has a significantly smaller volumetric capacity for intermediate storage of the heat fluid (170) than the storage tank (65), wherein the small store (135) is connected fluidically to the first heating-circuit connection (150) and/or to the first secondary side (120) of the first heat exchanger (90), wherein the primary-circuit pump (125) is configured to convey the heat fluid (170) between the first secondary side (120) and the small store (135).
2. Heating device (15) according to Claim 1,
   wherein the small store (135) is arranged in parallel with respect to the first heating-circuit connection (150) and to the second heating-circuit connection (155).
3. Heating device (15) according to Claim 1,
   wherein the small store (135) is arranged in series between the first heating-circuit connection (150) and the first secondary side (120) of the first heat exchanger (90).
4. Heating device (15) according to one of the preceding claims,
   wherein at least one first secondary-circuit pump (140) is arranged between the small store (135) and the first heating-circuit connection (150), wherein the first secondary-circuit pump (140) is configured to convey the heat fluid (170) between the small store (135) and the first heating-circuit connection (150).
5. Heating device (15) according to one of the preceding claims,
   wherein the heat-fluid-transport device (35) has a flow-transfer valve (465), wherein the flow-transfer valve (465) has a closed position and an open position, wherein the flow-transfer valve (465) is switched into the closed position if a predefined opening pressure at the flow-transfer valve (465) is fallen below, wherein the flow-transfer valve (465) is switched into the open position if the predefined opening pressure at the flow-transfer valve (465) is exceeded, wherein the flow-transfer valve (465) is arranged in parallel with respect to the first heating-circuit connection (150) and to the second heating-circuit connection (155).
6. Heating device (15) according to one of the preceding claims,
   having a hot-water store (40) with a storage tank (65) and with a hot-water heat exchanger (70) arranged in the storage tank (65), wherein the storage tank (65) is configured to store hot water, wherein the heat-fluid-transport device (35) has a three-way valve (145), wherein a first valve connection (260) of the three-way valve (145) is connected fluidically to the second heating-circuit connection (155) and a second valve connection (265) of the three-way valve (145) is connected fluidically to the primary-circuit pump (125), wherein a first side (200) of the hot-water heat exchanger (70) is connected fluidically to a first branch (190) which is arranged between the first secondary side (120) and the small store (135), wherein a second side (290) of the hot-water heat exchanger (70) is connected fluidically to a third valve connection (270) of the three-way valve (145), wherein the three-way valve (145) has a first valve position and at least one second valve position, which is different from the first valve position, wherein, in the first valve position, the three-way valve (145) fluidically connects the second heating-circuit connection (155) to the primary-circuit pump (125), wherein, in the second valve position, the three-way valve (145) fluidically connects the second side of the hot-water heat exchanger (70) to the primary-circuit pump (125).
7. Heating device (15) according to Claim 6 and Claim 2,
   wherein the small store (135) has a first store connection (215) and a second store connection (220), wherein the first store connection (215) is connected between the first branch (190) and the first heating-circuit connection (150), wherein the second store connection (220) is connected between the second heating-circuit connection (155) and the three-way valve (145).
8. Heating device according to Claim 6 and Claim 3,
   wherein the small store (135) has a first store connection (215) and a second store connection (220), wherein the first store connection (215) is connected fluidically to the first branch (190) and the second store connection (220) is connected fluidically to the first heating-circuit connection (150), wherein the small store (135) fluidically connects the first branch (190) to the first heating-circuit connection (150).
9. Heating device according to one of the preceding claims,
   having an external unit (45) and an internal unit (50), wherein the heat pump (30) is arranged in the external unit (45) and has at least one second heat exchanger (95), wherein the second heat exchanger (95) is connected fluidically to the first heat exchanger (90) for exchange of heat, wherein the heat-fluid-transport device (35) and the small store (135) are arranged in the internal unit (50).
10. Heating device (15) according to one of the preceding claims,
    having a fluid line (175, 180, 185, 195, 205, 230, 235, 240, 245, 255, 275, 280, 285, 435, 445, 455) for conducting the heat fluid (170), wherein the fluid line (175, 180, 185, 195, 205, 230, 235, 240, 245, 255, 275, 280, 285, 435, 445, 455) has at least one arcuate portion, wherein the arcuate portion at least encloses an angle of at least 45°, preferably at least 90°, wherein the fluid line (175, 180, 185, 195, 205, 230, 235, 240, 245, 255, 275, 280, 285, 435, 445, 455) comprises at least one plastic and is pre-formed, wherein preferably the fluid line (175, 180, 185, 195, 205, 230, 235, 240, 245, 255, 275, 280, 285, 435, 445, 455) is arranged in a stress-free or low-stress manner.
11. Heating system (10)
    having a heating device (15) according to one of the preceding claims, and having a first heating circuit (20), wherein the first heating circuit (20) is connected to the first heating-circuit connection (150) and to the second heating-circuit connection (155) and is filled with the heat fluid (170), wherein the primary-circuit pump (125) is configured to convey the heat fluid between the small store (135) and the first secondary side (120) of the first heat exchanger (90).
12. Method for de-icing a heating device (15) according to one of Claims 1 to 10, having a heat pump (30), having a hot-water store (40), and having a heat-fluid-transport device (35),
    wherein the heat pump (30) has a refrigerant circuit (100) with a refrigerant (115), and has in each case one compressor (105) incorporated into the refrigerant circuit (100), one first heat exchanger (90) and one second heat exchanger (95), wherein, for operating the heating device (15), the heat pump (30) has at least a de-icing mode in which the heat pump (30) is operated for targeted heating of the second heat exchanger (95), wherein a primary-circuit pump (125) of the heat-fluid-transport device (35) is activated and the heated heat fluid (170) is conveyed to the first heat exchanger (90), wherein a second heat (Q₂) is transferred from the heat fluid (170) to the refrigerant (115), wherein the refrigerant (115) circulates in the refrigerant circuit (100) and the refrigerant (115) transfers the second heat (Q₂) to the second heat exchanger (95), wherein the second heat exchanger (95) is de-iced by way of the second heat (Q₂), wherein, upon attainment of a predefined operating parameter of the heating device (15), in particular of a temperature (T2) of the heat fluid (170), the heat fluid (170) is conducted through the hot-water store (40) and the second heat (Q₂) for de-icing the second heat exchanger (95) is extracted at least partially from the hot-water store (40), wherein, in the de-icing mode, prior to attainment of the predefined operating parameter, the heat fluid (170) is conveyed from a small store (135) of the heat-fluid-transport device (35) to the first heat exchanger (90), wherein the second heat (Q₂) for de-icing the second heat exchanger (95) is transferred from the heat fluid (170) stored in the small store (135) to the first heat exchanger (90).
13. Method according to Claim 12,
    wherein, in the heating mode, the primary-circuit pump (125) is controlled in such a way that the heat fluid (170) has a pressure which is greater than an opening pressure of a flow-transfer valve (465) of the heat-fluid-transport device (35).

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