EP4379267A1 - Heat pump system with gas separator - Google Patents

Abstract

The invention relates to a heat pump system 100, 200, 300 with a primary circuit 110, 210, 310 for conducting a coolant, a secondary circuit 120, 220, 320 for conducting water, and a heat exchanger 113, 213, 313 for transferring heat between the coolant and the water, wherein the secondary circuit comprises a gas separator 121, 221, 321 with a quick vent. The heat pump system is designed to close a first shut-off device or open a drain valve on the gas separator if a value that correlates with a gas flow from the quick vent exceeds a predefined threshold value. The heat pump system according to the invention makes it possible to reduce an amount of flammable coolant in the secondary circuit to a non-critical amount.

Description

The invention relates to a heat pump system with a gas separator and a corresponding method for controlling a heat pump system.

Such heat pump systems have a primary circuit for carrying a coolant and a secondary circuit for carrying water, whereby heat can be transferred between the coolant and the water by means of a heat exchanger.

However, when using flammable refrigerants, particularly hydrocarbons such as C3H8 (R290, propane), the problem has been recognized that a defect, for example a general defect, corrosion or a defect caused by freezing water, in the heat exchanger, which can be designed as a plate heat exchanger, for example, can cause refrigerant to enter the secondary circuit, particularly a heating area of the secondary circuit, which can then enter a house that is heated with the heating area via the distribution system of the secondary circuit and escape there via automatic vents or drain valves. When using propane as a refrigerant, which corresponds to a flammable refrigerant, an ignitable mixture can then form together with the room air, which then poses a danger to the house.

It is known from the state of the art to provide a drain valve and an automatic vent in the secondary circuit of a heat pump system to prevent coolant from entering the residential building, in order to safely remove flammable coolant entering the secondary circuit before it can escape into the house. In particular in propane applications, several valves/vents can also be provided, for example in a flow line and a return line of the secondary circuit. In some cases, a microbubble separator is also used, which can include an automatic vent.

The disadvantage of the current state of the art is that despite the installed vents and drain valves, a dangerous amount, i.e. more than 150 g, of flammable refrigerant can enter the secondary circuit, i.e. the heating area, unnoticed. Furthermore, flammable refrigerant can escape directly into a living area of the house through additional drain valves and open automatic vents, so that an ignitable gas mixture can form in the living area.

Until now, the state of the art has relied on an automatic vent and a drain valve, whereby the drain valve is designed in such a way that the drain valve in the secondary circuit responds before all other installed drain valves (approx. 0.5 bar below).

An aim underlying the present invention is to reduce the amount of flammable refrigerant that can enter the secondary circuit, and thus into a heating system of a house, to a non-critical amount by separating it from the water.

According to a first aspect of the invention, a heat pump system is proposed with a primary circuit for conducting a coolant, a secondary circuit for conducting water and a heat exchanger for transferring heat between the coolant and the water, wherein the secondary circuit comprises a gas separator with a quick vent and a first shut-off device, wherein the heat pump system is designed to close the first shut-off device in the event that a value that correlates with a gas flow from the quick vent exceeds a predefined threshold value.

Preferably, the heat pump system comprises a controller configured to (a) monitor a value that correlates with a gas flow from the quick vent, (b) detect an exceedance of the value that correlates with the gas flow from the quick vent above a predefined threshold, and (c) close the first shut-off device in the event that the value that correlates with the gas flow from the quick vent exceeds the predefined threshold.

The quick vent valve is designed to discharge a refrigerant and/or air that enters the gas separator in an open state.

A heat pump system that is designed to close the first shut-off device in the event that a value that correlates with a gas flow from the quick vent exceeds a predefined threshold value can prevent flammable coolant that has entered the secondary circuit from entering the heating area of the secondary circuit. The risk of fire in the living area can thus be reduced with the heat pump system according to the invention.

In particular, by means of a control system that is designed to monitor a value that correlates with a gas flow from the quick vent, to detect an exceedance of the value that correlates with the gas flow from the quick vent above a predefined threshold value, and to close the first shut-off device in the event that the value that correlates with the gas flow from the quick vent exceeds the predefined threshold value, it is possible to prevent flammable coolant that has entered the secondary circuit unnoticed from entering the heating area of the secondary circuit and thus the living area of a house. The risk of a fire in the living area can thus be reduced with the heat pump system according to the invention.

In particular, after a refrigerant has been detected by exceeding a value that correlates with the gas flow from the quick vent valve, a part of the secondary circuit in which no refrigerant is (yet) present can be sealed off from the part of the secondary circuit in which the refrigerant has been recognized, i.e. detected, so that this part continues to be free of flammable refrigerant.

The value of a gas flow from the quick vent can be understood as a value that correlates with a gas quantity from the gas separator. In particular, the value of a gas flow is a value of a gas quantity escaping from the gas separator through the quick vent or a value that correlates with a gas quantity escaping from the gas separator through the quick vent. The value of a gas flow does not necessarily have to be determined. Preferably, the predefined threshold value is set so that the first shut-off device is switched before or when the quick vent has reached its maximum performance, i.e. its maximum performance to release gas.

Preferably, the heat pump system according to the invention comprises a switch which is designed to close the first shut-off device in the event that a value which correlates with a gas flow from the quick vent exceeds a predefined threshold value.

There are various possibilities to obtain a switching signal depending on a value of a gas flow from the quick vent.

For example, the quick vent can have a buoyancy body, whereby the buoyancy body floats depending on a gas flow or depending on a gas quantity in the gas separator, in particular in the quick vent. In this case, the predefined threshold value is determined by the buoyancy body. If the gas flow from the quick vent exceeds the predefined threshold value, for example, the buoyancy body and actuates a microswitch, thereby closing the first shut-off device (or opening a drain valve, described below).

As an alternative to a buoyancy body, a paddle switch can also be provided, wherein the paddle switch is preferably provided outside the quick vent, particularly preferably outside the quick vent directly at an opening of the quick vent. In this case, the predefined threshold value is defined by the paddle switch. If the gas flow from the quick vent exceeds the predefined threshold value, the paddle switch opens (the quick vent or the opening of the quick vent) and actuates a microswitch, whereby the first shut-off device is closed (or a safety valve, which is described further below, is opened).

Alternatively, a pressure switch or pressure sensor can also be provided, for example, at a constriction or an orifice of the quick vent. In this case, the predefined threshold value depends on a pressure value at which the pressure switch switches or which the pressure sensor measures and at which a corresponding switching signal is output. The pressure value correlates with a flow pressure loss, which in turn depends on the gas flow from the quick vent. The pressure switch or pressure sensor can detect a flow pressure loss when the gas flow from the quick vent exceeds the predefined threshold value. If the gas flow from the quick vent exceeds the predefined threshold value, the first shut-off device is closed (or a drain valve, which is described further below, is opened).

Other possibilities are conceivable, such as determining a flow via a floating body, the position of which can be determined contactlessly using various methods, with a predefined position determining the predefined threshold value for the gas flow from the quick vent. In this embodiment, the first shut-off device is closed at a predefined position (or a drain valve, which is described further below, is opened).

Preferably, the quick vent comprises a buoyancy body or a paddle, wherein in case a value correlating with a gas flow from the gas separator exceeds the predefined threshold, the buoyancy body or the paddle buoys and actuates a microswitch configured to close the first (or open a vent valve, described further below).

In an advantageous embodiment of the first aspect of the invention, the secondary circuit comprises a second shut-off device, wherein the heat pump system or the control is further designed to, in the event that the value which correlates with the gas flow from the quick vent exceeds the predefined threshold value, the second shut-off device This allows the heat exchanger to be completely isolated from a heating area of the secondary circuit, which may be provided in a living area.

In a further advantageous embodiment of the first aspect of the invention, the gas separator, in particular the quick vent of the gas separator, comprises a detection device which is designed to detect when the value which correlates with the gas flow from the quick vent exceeds the predefined threshold value. The detection device is advantageously designed to detect a relative value which correlates with the gas flow from the quick vent. This makes it possible not to continuously detect an absolute value which correlates with the gas flow from the quick vent, but rather to only detect it when the value which correlates with the gas flow from the quick vent exceeds a predefined threshold value. Preferably, for example, a difference value which correlates with the gas flow from the quick vent can be used. Additionally or alternatively, the gas separator, in particular the detection device, can comprise a sensor, wherein the sensor is designed to determine a value that correlates with the gas flow from the quick vent, wherein the heat pump system or the control is designed to compare the determined value, which correlates with the gas flow from the quick vent, with the predefined threshold value.

The predefined threshold value can be determined in various ways. In an example in which a detection device with a throttle element is provided on the quick vent, the predefined threshold value can be determined depending on a pressure increase at the throttle element.

Advantageously, the gas separator and the first shut-off device are arranged in the flow direction of the water after the refrigerant/water heat exchanger, i.e. for example the condenser. This enables refrigerant to be detected at a point in the flow direction of the water before the first shut-off device, so that the first shut-off device prevents refrigerant from entering the area of the secondary circuit behind the first shut-off device.

Particularly preferably, the secondary circuit comprises a flow area, a heating area and a return area, wherein the gas separator is provided in a flow area and wherein the heating area can correspond to a heating system in a house. It is then advantageous that the first shut-off device is arranged in a flow area. In the case that the secondary circuit comprises a second shut-off device, it is preferred that the second shut-off device is arranged in the return area.

In a further advantageous embodiment of the first aspect of the invention, the first shut-off device comprises a valve. For example, the valve can be a solenoid valve, wherein the magnetization preferably occurs in response to the detection that the value that correlates with the gas flow from the quick vent has exceeded the threshold value. Alternatively, the valve can be a pressure-controlled shut-off valve, wherein the pressure control preferably occurs in response to the detection that the value that correlates with the gas flow from the quick vent has exceeded the threshold value. In particular, if the valve is a pressure-controlled shut-off valve, the pressure control can occur directly in response to a gas flow of the refrigerant and/or air through the quick vent. In the case where the gas separator has a shut-off valve, the predefined threshold value can depend, for example, on a response pressure of the shut-off valve.

It is further preferred that the quick vent comprises a volume flow limit sensor, wherein in the event that a value which correlates with a gas flow through the volume flow limit sensor exceeds a predefined threshold value for the volume flow, the first shut-off device is closed.

Particularly preferably, in the case of a second shut-off device in the secondary circuit, the second shut-off device is a check valve which prevents water, in particular a water-refrigerant mixture, from flowing through the second shut-off device against the flow direction of the water through the second shut-off device.

In particular in combination with the first shut-off device and possibly the second shut-off device, after detecting that a value that correlates with the gas flow from the quick vent has exceeded the predefined threshold value, the first shut-off device and possibly the second shut-off device can be closed and the coolant and/or air that has entered the secondary circuit, in particular the gas separator, can be discharged. The coolant cannot thus enter the secondary circuit, in particular the heating area of the secondary circuit, which can be arranged in a living area of a house.

Particularly preferably, the gas separator comprises a safety valve which opens at a predefined pressure and releases gas, in particular refrigerant, into an environment.

In a further advantageous variant of the above embodiments, the heat pump system or the control system is designed to open the first shut-off device and, if applicable, the second shut-off device after the coolant and/or air have been completely discharged from the gas separator, for example through the quick vent or the safety valve. This enables the water in the heating area of the secondary circuit to remain idle for as short a time as possible after closing the first shut-off device and, if applicable, the second shut-off device due to the defect through which a refrigerant has entered the secondary circuit and a return, as quickly as possible, to normal operation of the heat pump system.

In another advantageous embodiment of the first aspect of the invention, the heat pump system comprises a safety pressure relief valve between the first shut-off device and the second shut-off device in the case that the secondary circuit comprises a first shut-off device and a second shut-off device. This can prevent an excessive pressure increase in the secondary circuit, in particular in the heating area of the secondary circuit, when the first shut-off device and the second shut-off device are closed. The safety pressure relief valve preferably opens at 2.3 bar to 2.7 bar, particularly preferably at 2.5 bar.

In the case that the gas separator comprises a detection device, the first shut-off device and/or the second shut-off device is preferably directly electrically connected to the detection device. This ensures a delay-free and safe closing of the first shut-off device and/or the second shut-off device after, i.e. in response to, the detection of an exceedance of a predefined threshold value. In particular, the provision of a direct electrical connection leads to a safer solution than if a controller with software is provided.

The control according to the invention can be embedded in a control of the secondary circuit of the heat pump system and/or a control of the primary circuit of the heat pump system.

According to a second aspect of the invention, a method for controlling a heat pump system is provided, wherein the heat pump system comprises a primary circuit for conducting a coolant, a secondary circuit for conducting water, and a heat exchanger for transferring heat between the coolant and the water, wherein the method comprises at least the steps of: (a) determining a value that correlates with a gas flow in a quick vent of a gas separator in the secondary circuit, (b) comparing the value that correlates with the gas flow from the quick vent with a predefined threshold value, and (c) in the event that the value that correlates with the gas flow from the quick vent exceeds the predefined threshold value, closing a first shut-off device in the secondary circuit.

In an advantageous embodiment, the method comprises the further step of closing a second shut-off device in the secondary circuit in the event that the value correlating with the gas flow from the quick vent exceeds the predefined threshold value.

According to a third aspect of the invention, a heat pump system is proposed with a primary circuit for conducting a coolant, a secondary circuit for conducting water and a heat exchanger for transferring heat between the coolant and the water, wherein the secondary circuit comprises a gas separator with a quick vent and a drain valve and preferably a first shut-off device and/or a second shut-off device, wherein the heat pump system is designed to open the drain valve in the gas separator and preferably close the first shut-off device and/or the second shut-off device in the event that a value that correlates with a gas flow from the quick vent exceeds a predefined threshold value.

Preferably, the heat pump system comprises a controller configured to (a) monitor a value that correlates with a gas flow from the quick vent, (b) detect an exceedance of the value that correlates with the gas flow from the quick vent above a predefined threshold, and (c) in the event that the value that correlates with the gas flow from the quick vent exceeds the predefined threshold, open the drain valve in the gas separator and preferably close the first shut-off device and/or the second shut-off device.

The drain valve particularly preferably comprises a volume flow limit sensor, wherein in the event that a value that correlates with a gas flow through the drain valve exceeds a predefined threshold value, the drain valve is opened. For example, the volume flow limit sensor can comprise an electrically actuated valve, in particular a valve that can be electrically actuated via a paddle switch or a valve that can be actuated via a differential pressure switch.

Particularly preferably, the gas separator, in particular the quick vent, comprises a detection device which is designed to detect when the value for a gas flow from the quick vent exceeds the predefined threshold value. Additionally or alternatively, the gas separator, in particular the quick vent, can comprise a sensor, wherein the sensor is designed to determine a value which correlates with the gas flow from the quick vent, wherein the heat pump system or the control is designed to compare the determined value with a predefined threshold value. The term exceeding is used here regardless of whether the threshold value is greater or smaller than the initial value.

It is further preferred that the secondary circuit comprises a flow area, a heating area and a return area, wherein the first shut-off device is preferably arranged in the flow area and the second shut-off device is preferably arranged in the return area of the secondary circuit. Advantageously, the second shut-off device comprises a Check valve. A check valve is preferably closed by a backflow of water.

Furthermore, the heat pump system or the control system is preferably designed to open the first shut-off device and/or second shut-off device after the coolant and/or air have been completely discharged.

In addition, a safety pressure relief valve can be provided in the secondary circuit in the direction of water flow between the first shut-off device and the second shut-off device in order to release any excess pressure that may arise from closing the first shut-off device and the second shut-off device. The safety pressure relief valve preferably opens at 2.3 bar to 2.7 bar, particularly preferably at 2.5 bar.

The control of the heat pump system according to the third aspect of the invention can also be embedded in a control of the secondary circuit and/or a control of the primary circuit of the heat pump system.

The gas separator preferably comprises a safety valve which is designed to discharge a coolant and/or air which enters the gas separator. The safety valve is particularly preferably provided at the top of the gas separator or at an inlet of the gas separator. The safety valve in the gas separator preferably opens at 2.8 bar to 3.2 bar, particularly preferably at 3 bar.

According to a fourth aspect of the invention, a method for controlling a heat pump system is proposed, wherein the heat pump system comprises a primary circuit for conducting a coolant, a secondary circuit for conducting water and a heat exchanger for transferring heat between the coolant and the water, wherein the method comprises at least the steps of: (a) monitoring a value that correlates with a gas flow in a quick vent of a gas separator arranged in the secondary circuit, (b) detecting an exceedance of the value that correlates with the gas flow from the quick vent above a predefined threshold value, and (c) in the event that the value that correlates with the gas flow from the quick vent exceeds the predefined threshold value, opening a drain valve in the gas separator and preferably closing a first and/or second shut-off device.

According to a further aspect of the invention, a computer program is proposed with program means which cause a control of a heat pump system according to the invention to carry out the steps of the corresponding method according to the invention when the computer program is executed on the controller of the heat pump system. The computer program may be provided, stored and/or distributed on a suitable storage medium, such as an optical storage medium or a non-volatile electronic storage medium. It may also be provided together with or as part of a hardware component. The computer program may also be provided in other ways, such as via the Internet or via wired or wireless telecommunications means.

Features of advantageous embodiments of the invention are defined in particular in the subclaims, wherein further advantageous features, embodiments and refinements can also be inferred by the person skilled in the art from the above explanations and the following discussion.

Fig. 1

eine schematische Darstellung zur Illustration eines ersten Ausführungsbeispiels des erfindungsgemäßen Wärmepumpensystems,

Fig. 2

eine schematische Darstellung zur Illustration eines zweiten Ausführungsbeispiels des erfindungsgemäßen Wärmepumpensystems,

Fig. 3

eine schematische Darstellung zur Illustration eines dritten Ausführungsbeispiels des erfindungsgemäßen Wärmepumpensystems,

Fig. 4

eine schematische Darstellung zur Illustration eines ersten Gasabscheiders zur Verwendung in einem erfindungsgemäßen Wärmepumpensystem,

Fig. 5

eine schematische Darstellung zur Illustration eines zweiten Gasabscheiders zur Verwendung in einem erfindungsgemäßen Wärmepumpensystem,

Fig. 6

eine schematische Darstellung zur Illustration eines dritten Gasabscheiders zur Verwendung in einem erfindungsgemäßen Wärmepumpensystems, und

Fig. 7

ein schematisches Ablaufdiagramm eines Ausführungsbeispiels des erfindungsgemäßen Verfahrens zur Steuerung eines Wärmepumpensystems, wie es zum Beispiel in Fig. 1 dargestellt ist.

In the following, the present invention is further illustrated and explained using embodiments shown in the figures.

Fig.1

a schematic representation to illustrate a first embodiment of the heat pump system according to the invention,

Fig.2

a schematic representation to illustrate a second embodiment of the heat pump system according to the invention,

Fig.3

a schematic representation to illustrate a third embodiment of the heat pump system according to the invention,

Fig.4

a schematic representation to illustrate a first gas separator for use in a heat pump system according to the invention,

Fig.5

a schematic representation to illustrate a second gas separator for use in a heat pump system according to the invention,

Fig.6

a schematic representation to illustrate a third gas separator for use in a heat pump system according to the invention, and

Fig.7

a schematic flow diagram of an embodiment of the method according to the invention for controlling a heat pump system, as described for example in Fig.1 is shown.

In the accompanying drawings and the explanations to these drawings, corresponding or related elements are - where appropriate - are marked with corresponding or similar reference symbols, even if they are found in different embodiments.

Fig.1 shows a schematic representation to illustrate a first embodiment of the heat pump system according to the invention. The heat pump system 100 comprises a primary circuit 110 and a secondary circuit 120, wherein the primary circuit 110 comprises a coolant/air heat exchanger 111, for example in the form of an evaporator, a compressor 112, a coolant/water heat exchanger 113, for example in the form of a condenser, an expansion device 114, for example in the form of a throttle device, and a refrigeration circuit reversing device 115. The secondary circuit 120 comprises a gas separator 121 and a first shut-off device 122, a second shut-off device 123 and a circulation pump 124. In addition, a safety pressure relief valve (125) can be provided between the first shut-off device 122 and the second shut-off device 123.

The heat exchanger 113 corresponds to a heat exchanger for transferring heat between coolant, which is carried in the primary circuit 110, and water, which is carried in the secondary circuit 120. The gas separator 121 comprises a quick vent 127 and a safety valve 125 for discharging coolant from the gas separator 121, wherein the safety valve 125 is opened in the gas separator 121 in particular when the pressure is (too) high, i.e. at a pressure value that corresponds to or exceeds a pressure limit value of the safety valve 125 for opening.

The heat pump system is designed to close the first shut-off device 122 and, if applicable, the second shut-off device 123 in the event that the value for the gas flow exceeds the predefined threshold value for the gas flow.

The first shut-off device 122 is in the embodiment of Fig.1 in a flow area of the secondary circuit 120, in particular in the flow direction of the water after the gas separator 121. The second shut-off device 123 is arranged in a return area of the secondary circuit 120. The second shut-off device 123 is advantageously a check valve.

The first shut-off device 122 is directly pneumatically connected to the quick vent 127 of the gas separator 121 via a control line 129, which can also be understood as a signal line. The control line 129 can thus be understood as a pressure line that conducts a fluid that is liquid or gaseous, preferably gaseous. In addition, the quick vent 127 comprises a throttle element 128. The greater the amount of coolant that flows through the throttle element 128, the higher the pressure drop and thus the pressure in the control line 129. If a certain pressure is exceeded, the first shut-off device 122 and, if applicable, the second shut-off device 123, and thus closes the respective connection.

The actuating pressure of the first shut-off device 122, which is greater than zero, is preferably less than 1.2 bar, particularly preferably less than 1.0 bar, wherein the throttle element 128 is preferably an orifice or capillary.

Fig.2 shows a schematic representation to illustrate a second embodiment of the heat pump system according to the invention. The heat pump system 200 comprises a primary circuit 210 and a secondary circuit 220. The primary circuit 210 comprises a coolant/air heat exchanger 211, for example in the form of an evaporator, a compressor 212, a coolant/water heat exchanger 213, for example in the form of a condenser, an expansion device 214, in this example in the form of a collector and two throttle elements, and a refrigeration circuit reversing device 215. The primary circuit 210 is thermally connected to the secondary circuit 220 via the heat exchanger 213, wherein the heat exchanger 213 can be a plate heat exchanger, for example.

In the embodiment of the heat pump system shown, a safety valve 225, a gas separator 221, a first shut-off device 222, a circulation pump 224 and a second shut-off device 223 are arranged in the flow direction of the water in the secondary circuit 220. The gas separator 221 comprises a quick vent 227 with a volume flow limit sensor 228, which can be a volume flow sensor or volume flow limit switch, for example. The first shut-off device 222 is electrically connected to the volume flow limit sensor 228 and thus to the quick vent 227 of the gas separator 221 via a control line. The volume flow limit sensor 228 can be a throttle element, a paddle switch, a propeller, an impeller, a hot wire anemometer, a float, etc. In this embodiment, the safety valve 225 is provided upstream of the gas separator 221 in the flow direction. The heat pump system 200 is designed to close at least the first shut-off device 222 in the event that a value that correlates with a gas flow from the quick vent 227 exceeds a predefined threshold value for the volume flow. The threshold value can be selected, for example, depending on a pressure increase at the volume flow limit sensor 228. Preferably, the first shut-off device 222 is closed electrically, whereby pressure-controlled closing is also possible, as in Fig.1 shown.

Fig. 3 shows a schematic representation to illustrate a third embodiment of the heat pump system according to the invention. The heat pump system 300 comprises a primary circuit 310 and a secondary circuit 320, wherein the primary circuit 310 a refrigerant/air heat exchanger 311, a compressor 312, a refrigerant/water heat exchanger 313, an expansion device 314 and a refrigeration circuit reversing device 315. The secondary circuit 320 comprises a gas separator 321, a second shut-off device 323 and a circulation pump 324. The gas separator 321 has a quick vent 327 and a drain valve 325. The drain valve 325 is designed as an electrically controlled drain valve and is connected to the quick vent 327 via a volume flow limit sensor 328, which can be designed as a volume flow limit switch, for example. The volume flow limit sensor 328 defines a predefined threshold value for a gas flow from the quick vent 327. As an alternative to electrical actuation, pneumatic actuation can also be provided.

The heat pump system 300 is designed to open the drain valve 325 of the gas separator 321 if a value that correlates with a gas flow from the quick vent 327 exceeds a predefined threshold. The drain valve 325 preferably leads to the outside so that the coolant can escape from the secondary circuit 320. For example, a drain pipe to the outside can be provided on the gas separator for this purpose, wherein the drain pipe is connected to the drain valve. The drain pipe of the gas separator can be provided as a pipe on an already provided air duct to the outside. In addition, the heat pump system 300 can be designed to close the second shut-off device 323 if the value that correlates with the gas flow from the quick vent 327 exceeds the predefined threshold. The embodiment shown may also comprise a first shut-off device, wherein in the event that the value correlated with the gas flow from the quick vent 327 exceeds the predefined threshold value, the first shut-off device is also closed.

Fig.4 shows a schematic representation to illustrate a first gas separator 400 for use in a heat pump system according to the invention. The gas separator 400 is a centrifugal separator and comprises a tangential inlet 410 and a radial outlet 420. In an upper region, the gas separator 400 also comprises a quick vent 427 and a safety valve 425. The gas separator 400 has a first shut-off device 422 at the outlet 420, which in this embodiment is designed as a pressure-controlled shut-off device. As an alternative to a pressure-controlled shut-off device, a magnetically controlled shut-off device is also conceivable. The shut-off device 422 is controlled in such a way that if the value that correlates with the gas flow from the quick vent 427 exceeds a predefined threshold value, the first shut-off device 422 is closed.

Fig.5 shows a schematic representation to illustrate a second gas separator for use in a heat pump system according to the invention. The gas separator 500 is again a centrifugal separator and comprises a tangential inlet 510 and a radial outlet 520. In an upper region, the gas separator 500 comprises a quick vent 527 and a drain valve 525. The drain valve 525 is designed as a solenoid valve in this embodiment. The quick vent 527 comprises a microswitch 528 with a paddle. Depending on a dynamic gas pressure, i.e. a gas flow, from the quick vent 527, the microswitch 528 can be triggered and the solenoid valve can be controlled. In the event that the gas flow exceeds a predefined threshold value, the solenoid valve, i.e. the drain valve 525, is then opened. The second gas separator 500 in Fig.5 may have a safety valve (not shown), wherein the safety valve is then preferably provided at the top of the gas separator 500 or in the secondary circuit in front of the gas separator 500, particularly preferably at the inlet 510.

Fig.6 shows a schematic representation to illustrate a third gas separator 600 for use in a heat pump system according to the invention. The gas separator 600 is also a centrifugal separator with a tangential inlet 610 and a radial outlet 620. The gas separator 600 comprises a quick vent 627 and a drain valve 625. A time-dependent pressure, i.e. a value that correlates with a gas flow from the quick vent 627, can be monitored via a volume flow limit sensor on the quick vent 627, which in this embodiment comprises a throttle element 628 and a pressure switch. If the value that correlates with the gas flow from the quick vent 627 exceeds a predefined threshold value, the drain valve 625 is opened. In particular, a differential pressure is measured via the throttle element 628, wherein the differential pressure can in turn be converted into a volume flow. The third gas separator 600 in Fig.6 may comprise a safety valve (not shown), wherein the safety valve is preferably provided at the top of the gas separator 600 or in the secondary circuit upstream of the gas separator 500, particularly preferably at the inlet 610.

Fig.7 shows a schematic flow diagram of an embodiment of the method 700 according to the invention. The method is intended for controlling a heat pump system, wherein the heat pump system comprises a primary circuit for conducting a coolant, a secondary circuit for conducting water and a heat exchanger for transferring heat between the coolant and the water, wherein the method comprises at least the steps 710, 720 and 730, which are described below.

In step 710, a value correlating with a gas flow in a gas separator in the secondary circuit is monitored. In step 720, the value correlating with the gas flow from the gas separator is compared with a predefined threshold value, and in Step 730, in the event that the value correlating with the gas flow from the gas separator exceeds the predefined threshold, a first shut-off device, and preferably also a second shut-off device, in the secondary circuit is closed.

The method 700 can be carried out, for example, by a heat pump system 100 according to the invention, in particular the corresponding control. In particular, the step of comparing can also be carried out passively, for example by a limit value transmitter which, at a predefined limit value, for example a pressure, outputs an electrical or pneumatic signal on the basis of which the first shut-off device and possibly the second shut-off device are closed.

Alternatively, in a step 730, if the value that correlates with the gas flow from the gas separator exceeds the predefined threshold value, a drain valve in the gas separator can be opened and, if necessary, a shut-off device, in particular a first shut-off device and/or a second shut-off device, can be closed.

The heat pump systems according to the invention and the corresponding methods ensure that, in the event of an internal leak in the heat exchanger, flammable coolant does not enter the heating area, which is normally located in a living area of a house, via the water circuit. The safety of living areas can thus be increased with the heat pump systems according to the invention.

Even if different aspects or features of the invention are shown in combination in the figures, it is clear to the person skilled in the art - unless otherwise stated - that the combinations shown and discussed are not the only possible ones. In particular, corresponding units or feature complexes from different embodiments can be exchanged with one another.

Further inventive considerations follow:
When developing a new air-water heat pump with R290, i.e. propane, as a refrigerant, the problem was recognized that a defect (for example a general defect or a defect caused by freezing water) in the heat exchanger, which can be a plate heat exchanger, for example, can cause refrigerant to enter the secondary circuit, i.e. the heating circuit of the heat pump, which can then enter a house via the distribution system.

The object of the present invention is to reduce the amount of flammable refrigerant entering the distribution system of the house to a non-critical amount by separating it from the water.

The invention can be applied to all new heat pump developments that use flammable refrigerants to operate the refrigeration circuit.

In order to prevent coolant from entering the residential building via the water circuit in the event of an internal leak in the coolant/water heat exchanger, one aspect of the invention involves installing a pressure-controlled shut-off valve, i.e. a shut-off device, in the flow direction after the gas separator. In this embodiment, the control line is connected to the outlet of the quick vent. The control line has an outlet that leads to the atmosphere via a throttle element.

If coolant enters the secondary circuit via the coolant/water heat exchanger, it is separated in the gas separator and fed via the quick vent into the control line, where it is released into the atmosphere via the throttle element. The greater the amount of coolant over time that flows through the throttle element, the greater the pressure drop and thus the pressure in the control line. If a certain pressure is exceeded, the first shut-off device switches and thus closes the connection to the residential building. A second shut-off device is also preferably installed in the return line to prevent gas from entering the residential building.

In order to prevent an excessive pressure increase in the water circuit when the shut-off device is activated, a safety pressure relief valve is preferably installed in the water circuit between the first and second shut-off devices. The second shut-off device is preferably designed as a backflow preventer, i.e. a check valve. The actuating pressure of the first shut-off device, which is greater than zero, is determined by the system pressure, i.e. the water pressure in the secondary circuit, and is preferably less than 1.2 bar, particularly preferably less than 1 bar. The throttle element is preferably an orifice or capillary.

The invention relates to a heat pump system with a primary circuit for conducting a coolant, a secondary circuit for conducting water, and a heat exchanger for transferring heat between the coolant and the water, wherein the secondary circuit comprises a gas separator with a quick vent. The heat pump system is designed to close a first shut-off device or to open a drain valve on the gas separator in the event that a value that correlates with a gas flow from the quick vent exceeds a predefined threshold value. In particular, according to the invention, a control for the heat pump system is provided, wherein the controller is designed to (a) monitor a value that correlates with a gas flow from the quick vent, (b) detect an exceedance of the value that correlates with the gas flow from the quick vent above a predefined threshold value, and (c) in the event that the value that correlates with the gas flow from the quick vent exceeds the predefined threshold value, close the first shut-off device or open the drain valve on the gas separator. The heat pump system according to the invention makes it possible to reduce an amount of flammable coolant in the secondary circuit to a non-critical amount.

Claims (18)

Heat pump system (100, 200, 300) with: a primary circuit (110, 210, 310) for carrying a refrigerant, a secondary circuit (120, 220, 320) for carrying water, and a heat exchanger (113, 213, 313) for transferring heat between the refrigerant and the water, wherein the secondary circuit (120, 220, 320) comprises a gas separator (121, 221, 321, 400, 500, 600) with a quick vent (127, 227, 327, 427, 527, 627) and a first shut-off device (122, 222, 422), wherein the heat pump system (100, 200, 300) is designed to close the first shut-off device (122, 422) in the event that a value correlated with a gas flow from the quick vent (127, 227, 327, 427, 527, 627) exceeds a predefined threshold value. Heat pump system (100, 200, 300) according to claim 1, wherein the heat pump system (100, 200, 300) comprises a controller configured to (a) monitor a value that correlates with a gas flow from the quick vent (127, 227, 327, 427, 527, 627), (b) detecting an exceedance of the value correlated with the gas flow from the quick vent (127, 227, 327, 427, 527, 627) above a predefined threshold value, and (c) in the event that the value correlating with the gas flow from the quick vent (127, 227, 327, 427, 527, 627) exceeds the predefined threshold, to close the first shut-off device (122, 222, 422). Heat pump system (100, 200, 300) according to one of claims 1 and 2, wherein the secondary circuit (120, 220, 320) comprises a second shut-off device (123, 223, 323), wherein in the event that the value correlating with the gas flow from the quick vent (127, 227, 327, 427, 527, 627) exceeds the predefined threshold value, the second shut-off device (123, 223, 323) is closed. Heat pump system (100, 200, 300) according to one of the preceding claims, wherein the heat pump system (100, 200, 300) comprises a switch which is designed to close the first shut-off device (122, 422) in the event that a value which correlates with a gas flow from the quick vent (127, 227, 327, 427, 527, 627) exceeds a predefined threshold value. Heat pump system (100, 200, 300) according to one of the preceding claims, wherein the gas separator (121, 221, 321, 400, 500, 600) comprises a detection device (228, 328, 528) which is designed to detect the exceeding of the value associated with the gas flow from the quick vent (127, 227, 327, 427, 527, 627) correlated to detect above the predefined threshold. Heat pump system (100, 200, 300) according to claim 5, wherein the detection device comprises a sensor. Heat pump system (100, 200, 300) according to one of the preceding claims, wherein the first shut-off device (122, 422) has a valve, wherein the valve is in particular a solenoid valve (222) or a pressure-controlled shut-off valve (122, 422). Heat pump system (100, 200, 300) according to one of the preceding claims, wherein the quick vent (127, 227, 327, 427, 527, 627) comprises a volume flow limit sensor (228, 328) and wherein in the event that a value correlated with a gas flow exceeds a predefined threshold value for the volume flow, the first shut-off device (122, 422) is closed. Heat pump system (100, 200, 300) according to one of the preceding claims, wherein the quick vent (127, 227, 327, 427, 527, 627) comprises a buoyancy body or a paddle, wherein in the event that a value correlated with a gas flow from the gas separator (121, 221, 321, 400, 500, 600) exceeds the predefined threshold value, the buoyancy body or the paddle floats and actuates a microswitch which is designed to close the first shut-off device (122, 222, 422). Heat pump system (100, 200, 300) according to one of the preceding claims, wherein the gas separator (121, 221, 321, 400, 500, 600) comprises a safety valve (125, 225, 425) designed to discharge a coolant and/or air that enters the gas separator (121, 221, 321, 400, 500, 600). Heat pump system (100, 200, 300) according to one of the preceding claims, wherein the heat pump system (100, 200, 300) is designed to open the first shut-off device (122, 222, 422) after the coolant and/or air have been completely discharged from the gas separator (121, 221, 321, 400, 500, 600). Heat pump system (100, 200, 300) according to claim 2, wherein the control is embedded in a control of the secondary circuit and/or a control of the primary circuit. Method for controlling a heat pump system, wherein the heat pump system (100, 200, 300) comprises a primary circuit (110, 210, 310) for conducting a coolant, a secondary circuit (120, 220, 320) for conducting water, and a heat exchanger (113, 213, 313) for transferring heat between the coolant and the water, the method comprising at least the steps: Monitoring a value associated with a gas flow in a quick vent (127, 227, 327, 427, 527, 627) of a gas separator (121, 221, 321, 400, 500, 600) in the secondary circuit (120, 220, 320), Comparing the value correlated with the gas flow from the quick vent (127, 227, 327, 427, 527, 627) with a predefined threshold value, and in the event that the value correlating with the gas flow from the quick vent (127, 227, 327, 427, 527, 627) exceeds the predefined threshold, closing a first shut-off device (122, 222, 422) in the secondary circuit (120, 220, 320). Heat pump system (100, 200, 300) with: a primary circuit (110, 210, 310) for carrying a refrigerant, a secondary circuit (120, 220, 320) for carrying water, and a heat exchanger (113, 213, 313) for transferring heat between the refrigerant and the water, wherein the secondary circuit (120, 220, 320) comprises a gas separator (121, 221, 321, 400, 500, 600) with a quick vent (127, 227, 327, 427, 527, 627) and a drain valve (325, 525, 625), wherein the heat pump system (100, 200, 300) is configured to open the drain valve (325, 525, 625) in the gas separator (121, 221, 321, 400, 500, 600) in the event that a value correlating with a gas flow from the quick vent (127, 227, 327, 427, 527, 627) exceeds a predefined threshold. Heat pump system (100, 200, 300) according to claim 14, wherein the heat pump system (100, 200, 300) comprises a controller which is designed (a) monitor a value that correlates with a gas flow from the quick vent (127, 227, 327, 427, 527, 627), (b) detecting an exceedance of the value correlated with the gas flow from the quick vent (127, 227, 327, 427, 527, 627) above a predefined threshold value, and (c) in case the value correlating with the gas flow from the quick vent (127, 227, 327, 427, 527, 627) exceeds the predefined threshold value, to open the drain valve (325, 525, 625) in the gas separator (121, 221, 321, 400, 500, 600) and preferably to close the first shut-off device (122, 222, 422) and/or the second shut-off device (123, 223, 323). Heat pump system (100, 200, 300) according to one of claims 14 and 15, wherein the gas separator (121, 221, 321, 400, 500, 600) comprises a volume flow limiter and wherein in the event that a value correlated with a gas flow through the volume flow limiter exceeds a predefined threshold value, the drain valve (325, 525, 625) is opened. Heat pump system (100, 200, 300) according to claim 16, wherein the volume flow limit value transmitter is an electrical switch for an electrically actuated valve, in particular a valve electrically actuated via a paddle switch or a valve actuated via a differential pressure switch. Heat pump system (100, 200, 300) according to one of claims 14 to 16, wherein the gas separator (121, 221, 321, 400, 500, 600) comprises a safety valve (125, 225, 425) designed to discharge a coolant and/or air that enters the gas separator (121, 221, 321, 400, 500, 600).

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