Deaerator for heat pump system

Abstract

The disclosure relates to a system and method for mitigating risk of presence of a leak in a heat exchanger of a heat pump system, in particular using flammable heating fluid, for heating a building. The method comprising determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system. The sensor is configured for sensing one or more of (a) a gas flow through a vent, (b) a pressure in a housing, (c) a secondary liquid level in the housing, (d) a position and / or displacement of a float in the housing, (e) a temperature in the housing, and (f) a flammable gas content in the housing.

Description

[0001] Title: Deaerator for heat pump system

[0002] FIELD

[0003] The invention relates to a degassing device configured for mitigating risk, in particular in view of flammable heating fluids, in a heat pump system configured for heating a building. The invention also relates to a heat pump system with reduced risk. The invention also relates to a method for reducing risk, in particular in view of flammable heating fluids, in a heat pump system configured for heating a building.

[0004] BACKGROUND

[0005] Heat pumps find wide spread use in heating systems for buildings, such as domestic dwellings or office buildings.

[0006] The change in refrigerants I heating fluids for (domestic) heat pumps from freon to propane forces the heating industry to use well sized deaerators and pressure relief valves in the secondary loop of the heat pump i.e. the hydronic heating system. A possible leak in the condenser may be the cause for introducing flammable gas in the secondary loop, i.e. in the heating system in a building. According the standard IEC 60335-2-40 an automatic air / refrigerant separator and pressure relief valve should be placed on the outlet pipe from the condenser.

[0007] SUMMARY

[0008] It is an object to provide a method and / or system allowing to mitigate risk of a possible leak in a heat exchanger of a heat pump system

[0009] According to a first aspect is provided a method for determining a risk of presence of a leak in a heat exchanger of a heat pump system. In particular the heat pump system can be configured for heating a building. The heat pump system can comprise a heat pump having a primary fluid flow circuit, also referred to as heat pump flow circuit herein, extending through a primary side of the heat exchanger, such as a condenser, and a secondary fluid flow circuit, also referred to as closed heating flow circuit herein, extending through a secondary side of the heat exchanger. The secondary fluid flow circuit can be a hydronic circuit. A primary fluid, such as a primary refrigerant, e.g. a primary liquid, can flow, e.g. circulate, through the primary flow circuit. A secondary fluid, such as a secondary heating liquid, e.g. water, can flow, e.g. circulate, through the secondary flow circuit. The primary fluid can comprise a flammable constituent, such as propane. The heat pump system comprises a degassing device. The degassing device comprises a housing having a fluid inlet port and a fluid outlet port for connection to the closed heating flow circuit. The housing forms an internal chamber. The internal chamber can comprise a flow resistor. The flow resistor can enhance separating of gas and / or gas bubbles from the secondary fluid. The degassing device comprises a vent configured to be automatically opened for allowing gas to exit the closed heating flow circuit when an amount of gas present in the housing is more than a predetermined threshold amount. Optionally, the degassing device comprises a pressure relief valve configured to be automatically opened for allowing gas to exit the closed heating flow circuit when a pressure of gas present in the housing is higher than a predetermined threshold pressure. The degassing device comprises a sensor for sensing one or more of

[0010] (a) a gas flow through the vent,

[0011] (b) a pressure in the housing,

[0012] (c) a gas volume in the housing,

[0013] (d) a secondary liquid level in the housing,

[0014] (e) a position and / or displacement of a float in the housing,

[0015] (f) a temperature in the housing,

[0016] (g) a temperature at the vent,

[0017] (h) a flammable gas content in the housing. The method comprises determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system.

[0018] The method determines that there is a risk of presence of a leak in a heat exchanger of a heat pump system, i.e. that there is deemed to be a leak present in the heat exchanger allowing the primary fluid to enter the closed heating flow circuit. It will be appreciated that the determination of a risk of presence of a leak in the heat exchanger of the heat pump system is not necessarily proof of an actual presence of a leak in the heat exchanger of the heat pump system. Nevertheless, the risk of presence of a leak in the heat exchanger of the heat pump system is sufficiently serious, e.g. in view of fire hazard or other dangers to occupants of the building, that determining that there is a risk of presence of a leak in the heat exchanger of the heat pump system can warrant immediate action, such as notification of the occupants and / or taking risk-mitigating measures in view of the heat pump system. Hence, the method of determining that there is a risk of presence of a leak in a heat exchanger of a heat pump system, can also provide for mitigating the risk of the presence of the leak by notification of the occupants and / or taking risk-mitigating measures in view of the heat pump system.

[0019] The sensor can be configured for determining a measured value of one or more of (a) the gas flow through the vent, (b) the pressure in the housing, (c) the gas volume in the housing, (d) the secondary liquid level in the housing, (e) the position and / or displacement of the float in the housing, (f) the temperature in the housing, (g) the temperature at the vent, (gh) the flammable gas content in the housing. The method can comprise determining, on the basis of the measured value(s) provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system. The method can further comprise, in response to determining the risk of presence of a leak in the heat exchanger of the heat pump system, such as the determined risk exceeding a threshold risk, automatically stopping, or at least diminishing, flow in the closed heating flow circuit and / or the heat pump flow circuit. This can prevent spreading of a flammable constituent throughout the closed heating flow circuit, such as throughout the building. Hence, risk to occupants may be reduced. It will be appreciated that it is not always necessary to output, such as notify, the determination of the risk of presence of a leak in the heat exchanger of the heat pump system, e.g. to the occupants or caretakers, in case of automatically stopping, or at least diminishing, flow in the closed heating flow circuit and / or the heat pump flow circuit. The notification of the risk of presence of a leak in the heat exchanger of the heat pump system can, under circumstances, be dispensed with.

[0020] The closed heating flow circuit can comprise a pump, e.g. upstream of the heat exchanger, and / or a shut-off valve, e.g. downstream of the heat exchanger. The pump is configured for pumping the secondary fluid through the closed heating flow circuit. The method can comprise automatically stopping, or at least diminishing, flow in the closed heating flow circuit by stopping, or at least reducing pump speed of, the pump. Stopping the pump can stop flow in the closed heating flow circuit. Stopping, or at least reducing speed of, the pump can stop, or diminish, primary fluid, such as flammable constituent, leaked into the closed heating flow circuit at the heat exchanger from spreading through the closed heating flow circuit. The shut-off valve is configured to block flow through the closed heating flow circuit when closed. The method can comprise automatically stopping, or at least diminishing, flow in the closed heating flow circuit by, at least partially, closing the shut-off valve of the closed heating flow circuit. Closing the shut-off valve can stop primary fluid, such as flammable constituent, leaked into the closed heating flow circuit at the heat exchanger from spreading through the closed heating flow circuit.

[0021] The closed heating flow circuit can comprise a blow-off valve in the closed heating flow circuit. The blow-off valve can be configured to allow gas to exit the closed heating flow circuit when opened. Alternatively, or additionally, the method can comprise, in response to determining the risk of presence of a leak in the heat exchanger of the heat pump system, such as the determined risk exceeding a threshold risk, automatically opening the blow-off valve. Opening the blow-off valve can allow primary fluid, such as flammable constituent, leaked into the closed heating flow circuit at the heat exchanger to escape from the closed heating flow circuit. The blow-off valve can be separate from the vent. The vent can be positioned on an inside of the building. The blow-off valve can be positioned on an outside of the building, or at least such as to blow off to an outside of the building. It will be appreciated that it is also possible that the vent is positioned to the outside of the building, or at least vents to the outside of the building.

[0022] Alternatively, or additionally, the method can comprise, in response to determining the risk of presence of a leak in the heat exchanger of the heat pump system, such as the determined risk exceeding a threshold risk, automatically closing the vent and / or preventing the vent from opening. Closing the vent and / or preventing the vent from opening can prevent, or at least diminish, gas, such as a flammable constituent, escaping via the vent.

[0023] The heat pump can comprise a compressor. Alternatively, or additionally, the method can comprise, in response to determining the risk of presence of a leak in the heat exchanger of the heat pump system, such as the determined risk exceeding a threshold risk, automatically stopping the compressor. Stopping the compressor can stop flow in the heat pump flow circuit, thereby stopping, or at least reducing leaking of the primary fluid, such as flammable constituent, into the closed heating flow circuit at the heat exchanger.

[0024] The heat pump can comprise a shut-off valve in the heat pump flow circuit, e.g. instead of or in addition to the shut-off valve of the closed heating flow circuit. Alternatively, or additionally, the method can comprise, in response to determining the risk of presence of a leak in the heat exchanger of the heat pump system, such as the determined risk exceeding a threshold risk, automatically closing the shut-off valve of the heat pump. Closing the shut-off valve of the heat pump can stop flow in the heat pump flow circuit, thereby stopping, or at least reducing leaking of the primary fluid, such as flammable constituent, into the closed heating flow circuit at the heat exchanger.

[0025] The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects a gas flow through the vent exceeding a first threshold. A high flow of gas through the vent can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0026] The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects an increase rate in gas flow through the vent exceeding a second threshold. A rapid increase in flow rate of gas through the vent can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0027] The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects a pressure in the housing exceeding a third threshold. A high pressure of gas in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0028] The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects a pressure increase rate in the housing exceeding a fourth threshold. A rapid increase in the pressure of gas in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0029] The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects a secondary liquid level in the housing dropping below a fifth threshold (herein also referred to as exceeding the fifth threshold). A low level of liquid in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0030] The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects a secondary liquid level decrease rate in the housing exceeding a sixth threshold. A rapid decrease of the liquid level in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0031] The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects a position of a float in the housing dropping below a seventh threshold (herein also referred to as exceeding the seventh threshold). A low position of the float in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger. The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects a displacement of the float in the housing exceeding an eighth threshold. A large displacement of the float in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0032] The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects a displacement rate of the float in the housing exceeding a ninth threshold. A rapid displacement of the float in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0033] The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects a temperature in the housing, or at the vent, being below a tenth threshold (herein also referred to as exceeding the tenth threshold). A low temperature, in the housing, or at the vent, can be representative of a large amount of gas escaping at the vent, which can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0034] The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects a temperature change rate in the housing, or at the vent, exceeding an eleventh threshold. A rapid temperature change in the housing, or at the vent, can be representative of a large amount of gas escaping at the vent, which can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0035] The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects a flammable gas content in the housing exceeding a twelfth threshold. A high flammable gas content in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0036] The method can comprise determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system in case the sensor detects a flammable gas content change rate in the housing exceeding a thirteenth threshold. A high flammable gas content change rate in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0037] Optionally, the determining the risk of presence of a leak in the heat exchanger of the heat pump system is performed by the sensor. The sensor can compare a sensed signal, such as a measured value, to the relevant one of the first through thirteenth threshold values.

[0038] Optionally, the sensor transmits a command to stop, or at least diminishing, flow in the closed heating flow circuit, such as by stopping, or at least reducing pump speed of, the pump and / or closing the shut-off valve of the closed heating flow circuit; and / or a command to open the blow-off valve; and / or a command to close the vent and / or prevent the vent from opening; and / or a command to stop the compressor; and / or a command to close the shut-off valve of the heat pump. The command can be transmitted to the pump, shut-off valve, blow-off valve, vent, and / or compressor. The command can be transmitted to a controller controlling the pump, shut-off valve, blow-off valve, vent, and / or compressor. The controller can be a controller associated with the degassing device. The controller can be a controller of the heat pump system.

[0039] Optionally, the sensor transmits a signal to a controller, e.g. the controller associated with the degassing device and / or the controller of the heat pump system. The signal can be representative of the sensing by the sensor. The signal can be representative of the measured value(s). The signal can be representative of the exceeding of one or more of the first through fifteenth thresholds.

[0040] Optionally, the determining the risk of presence of a leak in the heat exchanger of the heat pump system is performed by the controller. The sensor can compare the signal received from the sensor, such as a measured value, to the relevant one of the first through thirteenth threshold values.

[0041] Optionally, the controller, e.g. the controller associated with the degassing device and / or the controller of the heat pump system, transmits a command to stop, or at least diminishing, flow in the closed heating flow circuit, such as by stopping, or at least reducing pump speed of, the pump and / or closing the shut-off valve of the closed heating fluid circuit; and / or a command to open the blow-off valve; and / or a command to close the vent and / or prevent the vent from opening; and / or a command to stop the compressor; and / or a command to close the shut-off valve of the heat pump. The command can be transmitted to the pump, shut-off valve, blow-off valve, and / or vent.

[0042] According to a second aspect is provided a deaerator, herein also referred to as degassing device, for a heat pump system, such as referred to above. In particular the heat pump system can be configured for heating a building. The heat pump system comprises a heat pump having a primary fluid flow circuit, also referred to as heat pump flow circuit herein, extending through a primary side of a heat exchanger and a secondary fluid flow circuit, also referred to as closed heating flow circuit herein, extending through a secondary side of the heat exchanger. A secondary fluid, such as a secondary liquid, can flow, e.g. circulate, through the closed heating flow circuit. A primary fluid, such as a primary liquid, can flow, e.g. circulate, through the heat pump flow circuit. The primary fluid can comprise a flammable constituent, such as propane. The degassing device comprises a housing having a fluid inlet port and a fluid outlet port for connection to the closed heating flow circuit. The housing forms an internal chamber. The internal chamber can comprise a flow resistor. The flow resistor can enhance separating of gas and / or gas bubbles from the secondary fluid. The degassing device comprises a vent configured to be automatically opened for allowing gas to exit the closed heating flow circuit when an amount of gas present in the housing is more than a predetermined threshold amount. Optionally, the degassing device comprises a pressure relief valve configured to be automatically opened for allowing gas to exit the closed heating flow circuit when a pressure of gas present in the housing is higher than a predetermined threshold pressure. The degassing device comprises a sensor for sensing one or more of

[0043] (a) a gas flow through the vent,

[0044] (b) a pressure in the housing,

[0045] (c) a gas volume in the housing,

[0046] (d) a secondary liquid level in the housing,

[0047] (e) a position and / or displacement of a float in the housing,

[0048] (f) a temperature in the housing,

[0049] (g) a temperature at the vent,

[0050] (h) a flammable gas content in the housing.

[0051] The sensor can be configured for determining a measured value of one or more of (a) the gas flow through the vent, (b) the pressure in the housing, (c) the gas volume in the housing, (d) the secondary liquid level in the housing, (e) the position and / or displacement of the float in the housing, (f) the temperature in the housing, (g) the temperature at the vent, (h) the flammable gas content in the housing. The sensor is configured for providing, on the basis of the sensing, a signal configured to stop, or at least diminish, flow in the closed heating flow circuit and / or the heat pump flow circuit. This can prevent spreading of a flammable constituent throughout the closed heating flow circuit, such as throughout the building.

[0052] The closed heating flow circuit can comprise a pump, e.g. upstream of the heat exchanger, and / or a shut-off valve, e.g. downstream of the heat exchanger. The pump is configured for pumping the secondary fluid through the closed heating flow circuit. Stopping the pump can stop flow in the closed heating flow circuit. Reducing the pump speed can diminish flow in the closed heating flow circuit. Stopping, or diminishing pumping by, the pump can stop primary fluid, such as flammable constituent, leaked into the closed heating flow circuit at the heat exchanger from spreading through the closed heating flow circuit. The shut-off valve in the closed heating flow circuit is configured to block flow through the closed heating flow circuit when closed. Closing the shut-off valve can stop primary fluid, such as flammable constituent, leaked into the closed heating flow circuit at the heat exchanger from spreading through the closed heating flow circuit.

[0053] Alternatively, or additionally, the sensor is configured for providing, on the basis of the sensing, a signal configured to open a blow-off valve of the closed heating flow circuit. The blow-off valve can be configured to allow gas to exit the closed heating flow circuit when opened. Opening the blow-off valve can allow primary fluid, such as flammable constituent, leaked into the closed heating flow circuit at the heat exchanger to escape from the closed heating flow circuit. The blow-off valve can be separate from the vent. The vent can be positioned on an inside of the building. The blowoff valve can be positioned on an outside of the building, or at least such as to blow off to an outside of the building.

[0054] Alternatively, or additionally, the sensor is configured for providing, on the basis of the sensing, a signal configured to close the vent and / or prevent the vent from opening. Closing the vent and / or preventing the vent from opening can prevent, or at least diminish, primary fluid, such as flammable constituent, escaping via the vent.

[0055] Alternatively, or additionally, the sensor is configured for providing, on the basis of the sensing, a signal configured to stop a compressor of the heat pump.

[0056] Alternatively, or additionally, the sensor is configured for providing, on the basis of the sensing, a signal configured to close a shut-off valve of the heat pump flow circuit

[0057] According to a third aspect is provided a heat pump system for heating a building, such as referred to above. The heat pump system comprises a heat pump having a primary fluid flow circuit, also referred to as heat pump flow circuit herein, extending through a primary side of a heat exchanger. The heat pump system comprises a secondary fluid flow circuit, also referred to as closed heating flow circuit herein, extending through a secondary side of the heat exchanger. A secondary fluid, such as a secondary liquid, can flow, e.g. circulate, through the closed heating flow circuit. A primary fluid, such as a primary liquid, can flow, e.g. circulate, through the heat pump flow circuit. The primary fluid can comprise a flammable constituent, such as propane. The closed heating flow circuit can comprise a pump, e.g. upstream of the heat exchanger, and / or a shut-off valve, e.g. downstream of the heat exchanger, and / or and / or a blow-off valve. The shutoff valve is configured to block flow through the closed heating flow circuit when closed. The blow-off valve is configured to allow gas to exit the closed heating flow circuit when opened. The heat pump flow circuit can comprise a compressor and / or a shut-off valve. The compressor is configured for increasing a pressure and temperature of the primary fluid. The shut-off valve is configured to block flow through the heat pump flow circuit when closed. The heat pump system comprises a degassing device in the closed heating flow circuit. The degassing device can be a deaerator device. The degassing device comprises a housing having a fluid inlet port and a fluid outlet port connecting to the closed heating flow circuit, the housing forming an internal chamber. The internal chamber can comprise a flow resistor. The flow resistor can enhance separating of gas and / or gas bubbles from the secondary fluid. The degassing device comprises a vent configured to be automatically opened for allowing gas to exit the closed heating flow circuit when an amount of gas present in the housing is more than a predetermined threshold amount. The vent can be separate from the blow-off valve. The vent can be positioned on an inside of the building or on an outside of the building. The blow-off valve can be positioned on an outside of the building, or at least such as to blow off to an outside of the building. Optionally, the degassing device comprises a pressure relief valve configured to be automatically opened for allowing gas to exit the closed heating flow circuit when a pressure of gas present in the housing is higher than a predetermined threshold pressure. The degassing device comprises a sensor for sensing one or more of (a) a gas flow through the vent, (b) a pressure in the housing, (c) a gas volume in the housing, (d) a secondary liquid level in the housing, (e) a position and / or displacement of a float in the housing, (f) a temperature in the housing, (g) a temperature at the vent, (h) a flammable gas content in the housing. The sensor can be configured for determining a measured value of one or more of (a) the gas flow through the vent, (b) the pressure in the housing, (c) the gas volume in the housing, (d) the secondary liquid level in the housing, (e) the position and / or displacement of the float in the housing, (f) the temperature in the housing, (g) the temperature at the vent, (h) the flammable gas content in the housing.

[0058] In view of the first, second and third aspects, the following applies. The degassing device can be associated with a controller. For instance, a system can be provided comprising the degassing device and the controller. The degassing device can comprise the controller. The system can additionally comprise the pump, the shut-off valve of the primary fluid flow circuit, the shut-off valve of the secondary fluid flow circuit, the compressor, and / or the blow-off valve. The controller can be part of the heat pump system. The controller can be part of the heat pump. The controller can be communicatively connected to the sensor. Thereto, the controller can be wiredly or wirelessly connected to the sensor. The controller can be configured to stop, or at least diminish, flow in closed heating flow circuit by stopping the pump, and / or closing the shut-off valve of the secondary fluid flow circuit. Alternatively, or additionally, the controller can be configured to open the blow-off valve. Alternatively, or additionally, the controller can be configured to close the vent, or to prevent the vent from opening. Alternatively, or additionally, the controller can be configured to stop the compressor. Alternatively, or additionally, the controller can be configured to close the shut-off valve of the primary fluid flow circuit.

[0059] The sensor can be configured to transmit, e.g. to the controller, a signal representative of the measured value. The controller can be configured to compare the measured value to a predetermined threshold value. Alternatively, or additionally, the sensor can be configured to compare the measured value to a predetermined threshold value. The sensor can be configured to transmit, e.g. to the controller, a signal in case the measured value exceeds the predetermined threshold value.

[0060] The controller can be configured to, in response to the sensor detecting a gas flow through the vent exceeding a first threshold, stop, or at least diminish, flow in closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor be configured to, in response detecting a gas flow through the vent exceeding the first threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A high flow of gas through the vent can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger. The controller can be configured to, in response to the sensor detecting an increase rate in gas flow through the vent exceeding a second threshold, stop, or at least diminish, flow in closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor be configured to, in response detecting an increase rate in gas flow through the vent exceeding the second threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A rapid increase in flow rate of gas through the vent can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0061] The controller can be configured to, in response to the sensor detecting a pressure in the housing exceeding a third threshold, stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor can be configured to, in response to detecting a pressure in the housing exceeding the third threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A high pressure of gas in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger. The controller can be configured to, in response to the sensor detecting a pressure increase rate in the housing exceeding a fourth threshold, stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor can be configured to, in response to detecting a pressure increase rate in the housing exceeding the fourth threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shutoff valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A rapid increase in the pressure of gas in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0062] The controller can be configured to, in response to the sensor detecting a secondary liquid level in the housing dropping below a fifth threshold, stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor can be configured to, in response to detecting a secondary liquid level in the housing dropping below the fifth threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A low level of liquid in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger. The controller can be configured to, in response to the sensor detecting a secondary liquid level decrease rate in the housing exceeding a sixth threshold, stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor can be configured to, in response to detecting a secondary liquid level decrease rate in the housing exceeding the sixth threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A rapid decrease of the liquid level in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0063] The controller can be configured to, in response to the sensor detecting a position of a float in the housing dropping below a seventh threshold, stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor can be configured to, in response to detecting a position of the float in the housing dropping below the seventh threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A low position of the float in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger. The controller can be configured to, in response to the sensor detecting a displacement of the float in the housing exceeding an eighth threshold, stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor can be configured to, in response to detecting a displacement of the float in the housing exceeding the eighth threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A large displacement of the float in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger. The controller can be configured to, in response to the sensor detecting a displacement rate of the float in the housing exceeding a ninth threshold, stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor can be configured to, in response to detecting a displacement rate of the float in the housing exceeding the ninth threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shutoff valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A rapid displacement of the float in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0064] The controller can be configured to, in response to the sensor detecting a temperature in the housing, or at the vent, being below a tenth threshold, stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor can be configured to, in response to detecting a temperature in the housing, or at the vent, being below the tenth threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A low temperature, in the housing, or at the vent, can be representative of a large amount of gas escaping at the vent, which can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger. The controller can be configured to, in response to the sensor detecting a temperature change rate in the housing, or at the vent, exceeding an eleventh threshold, stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor can be configured to, in response to detecting a temperature change rate in the housing, or at the vent, being below the eleventh threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A rapid temperature change in the housing, or at the vent, can be representative of a large amount of gas escaping at the vent, which can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger. The controller can be configured to, in response to the sensor detecting a flammable gas content in the housing exceeding a twelfth threshold, stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor can be configured to, in response to detecting a flammable gas content in the housing exceeding the twelfth threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A high flammable gas content in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger. The controller can be configured to, in response to the sensor detecting a flammable gas content change rate in the housing exceeding a thirteenth threshold, stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. The sensor can be configured to, in response to detecting a flammable gas content change rate in the housing exceeding the thirteenth threshold, transmit a command, e.g. to the controller, to stop, or at least diminish, flow in the closed heating flow circuit, e.g. stop the pump and / or close the shut-off valve of the secondary fluid flow circuit; and / or open the blow-off valve; and / or stop the compressor; and / or close the shut-off valve of the primary fluid flow circuit. A high flammable gas content change rate in the housing can be representative of gas leaking into the closed heating flow circuit at the heat exchanger. Optionally, the pump is configured to automatically stop when a flow in the closed heating flow circuit is below a predetermined threshold.

[0065] Optionally, the shut-off valve is positioned in the closed heating flow circuit downstream of the heat exchanger and upstream of the degassing device.

[0066] Optionally, the blow-off valve is positioned in the closed heating flow circuit downstream of the heat exchanger and upstream of the degassing device.

[0067] Optionally, a flow capacity of the blow-off valve larger than a flow capacity of the vent.

[0068] Optionally, the degassing device is placed on an outlet pipe of the secondary side of the heat exchanger.

[0069] Optionally, the vent comprises a valve and a float for automatically opening the valve for allowing gas to exit the housing when the amount of gas present in the housing is more than the predetermined threshold amount.

[0070] Optionally, the degassing device comprises a pressure relief valve configured to be automatically opened for allowing gas to exit the closed heating flow circuit when a pressure of gas present in the housing is higher than a predetermined threshold pressure.

[0071] It will be appreciated that any of the aspects, features and options described herein can be combined. It will particularly be appreciated that any of the aspects, features and options described in view of the method apply equally to the heat pump system and the degassing device, and vice versa.

[0072] BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings in which:

[0074] Figure 1 shows an example of a heat pump system; Figure 2 shows an example of a degassing device;

[0075] Figure 3 shows an example of a heat pump system; and Figure 4 shows an exemplary flow chart of a method.

[0076] DETAILED DESCRIPTION

[0077] Figure 1 shows an example of a heat pump system 1 for heating a building 100. The heat pump system 1 comprises a heat pump 2. The heat pump 2 comprises a primary flow circuit, herein also referred to as heat pump flow circuit, 4 extending through a primary side 6 of a heat exchanger 8, such as a condenser. The heat pump system 1 comprises a secondary flow circuit, herein also referred to as closed heating flow circuit, 10 extending through a secondary side 12 of the heat exchanger 8. A secondary fluid, such as a secondary liquid, can flow, e.g. circulate, through the closed heating flow circuit 10. A primary fluid, such as a primary liquid, can flow, e.g. circulate, through the heat pump flow circuit 4. The primary fluid can comprise a flammable constituent, such as propane. The heat pump system 2 here comprises a pump 14 for pumping the secondary fluid through the closed heating flow circuit 10. The pump 14 can be positioned upstream of the heat exchanger 8. The closed heating flow circuit 10 in this example comprises one or more secondary heat exchangers 16, such as radiators, infloor exchangers, in-wall exchangers, and / or in-ceiling exchangers, for heating an internal space 102 of the building 100. The heat pump system 2 here comprises a primary heat exchanger 18 for absorbing heat from surroundings, such as from ambient air or from a ground loop. The heat pump 2 here comprises a compressor 17 for increasing a pressure and temperature of the primary fluid. In this example, the heat pump 2 also comprises an expansion valve 19.

[0078] The heat pump system 1 comprises a degassing device 20 in the closed heating flow circuit 10. Figure 2 shows an example of a degassing device 20 in more detail. The degassing device 20 comprises a housing 22 having a fluid inlet port 24 and a fluid outlet port 26. The fluid inlet port 24 and the fluid outlet port 26 are in fluid communication with the closed heating flow circuit 10. Here, the degassing device 20 is placed on an outlet pipe of the secondary side 12 of the heat exchanger 8. The housing 22 forms an internal chamber 28. In this example, the internal chamber 28 comprises a flow resistor 30. The flow resistor 30 can enhance separating of gas and / or gas bubbles from the secondary fluid. The degassing device 20 comprises a vent 32 configured to be automatically opened for allowing gas to exit the closed heating flow circuit 10 when an amount of gas present in the housing 22 is more than a predetermined threshold amount. In this example, the vent 32 comprises a valve 33 operated by a float 34. The float 34 floats on a liquid level LL inside the internal chamber 28. In case the liquid level drops below a predetermined threshold liquid level, the float will move downward sufficiently to open the valve 33 of the vent 32 and allow gas to escape. In this example, the degassing device 20 comprises a pressure relief valve 35 configured to automatically open for allowing gas to exit the closed heating flow circuit 10 when a pressure of gas present in the housing 22 is higher than a predetermined threshold pressure. The pressure relief valve 35 is positioned above a liquid level in the housing 22.

[0079] In this example, the degassing device comprises a sensor 36. The sensor can include a plurality of sensors 36i. The plurality of sensors can include a gas flow sensor 36a configured to sense a gas flow through the vent. The gas flow sensor 36a can be positioned in or near an exhaust line of the vent 32. The plurality of sensors can include a pressure sensor 36b configured to sense a pressure in the housing. The pressure sensor 36b can be positioned inside the housing 22 above the liquid level LL. The plurality of sensors can include a secondary liquid level sensor 36c configured to sense a secondary liquid level in the housing. The secondary liquid level sensor 36c can be positioned at or near the liquid level LL. The plurality of sensors can include a float sensor 36d configured to sense a position and / or displacement of the float 34 in the housing. The float sensor 36d can be positioned near the float 34. More in general, the plurality of sensors can include sensor configured to determine a gas volume in the housing, such as e.g. the secondary liquid level sensor 36c or the float sensor 36d. The plurality of sensors can include a temperature sensor 36e configured to sense a temperature in the housing. The temperature sensor 36e can be positioned near the vent 32. In the shown example, the temperature sensor 36e is positioned near the fluid inlet port 24, here below the liquid level LL. The sensitivity of the temperature sensor 36e can be good at or near the fluid inlet port 24. The plurality of sensors can include a flammable gas content sensor 36f configured to sense a flammable gas content in the housing. The flammable gas content sensor 36f can be positioned inside the housing 22 above the liquid level LL.

[0080] The heat pump system 1, in this example, comprises a shut-off valve 38 in the closed heating flow circuit 10, e.g. downstream of the heat exchanger 8. The shut-off valve 38 can be upstream of the degassing device 20, e.g. when the degassing device is positioned inside the building 100. Preferably, the shut-off valve 38 is positioned downstream of the degassing device 20, e.g. when the degassing device is positioned outside, or vents to the outside, of the building. The shut-off valve 38 is configured to block flow through the closed heating flow circuit 10 when closed. It is also possible that the shut-off valve is placed in the heat pump flow circuit 4. It is also possible that a first shut-off valve is placed in the heat closed heating flow circuit 10 and a second shut-off valve is placed in the heat pump flow circuit 4. Here, the closed flow circuit 10 comprises a check valve 39. The check valve 39 can prevent, the primary fluid, or e.g. the flammable constituent, from leaking into the closed flow circuit 10 via a return path from the closed flow circuit to the heat exchanger 8.

[0081] The heat pump system 1, in this example, comprises a blow-off valve 40 in the closed heating flow circuit 10. Here, the blow-off valve 40 is positioned in the closed heating flow circuit 10 downstream of the heat exchanger 8 and upstream of the degassing device 20. The blow-off valve 40 can be configured to allow gas to exit the closed heating flow circuit 10 when opened. In this example, the blow-off valve 40 is positioned to an outside 104 of the building 100, or at least such as to blow off to the outside of the building 100. Here, the blow-off valve is separate from the vent 32. In this example, the vent 32 is also positioned to the outside of the building 100. It is possible that the vent 32 is positioned on an inside 102 of the building 100, the vent may allow gas to exit to the inside 102 of the building 100, or to the outside 104 of the building 100. A flow capacity of the blow-off valve 40 is larger than a flow capacity of the vent 32. Hence, exhaust of potentially dangerous gas via the blow-off valve can be performed faster than via the vent 32.

[0082] In the heat pump system 1, there is a risk of presence of a leak in a heat exchanger 8 of the heat pump 2. If such leak occurs, primary fluid can leak from the heat pump flow circuit 4 into the closed heating flow circuit 10. The primary fluid can comprise a flammable constituent, such as propane. Hence, in case of such leak, the primary fluid, in particular the flammable constituent, can spread through the closed heating flow circuit 10, e.g. throughout the building. This can cause a dangerous situation arising in the building 100, such as fire hazard. Hence, risk-mitigating measures and / or notification of occupants of the building may be necessary.

[0083] Thereto, the heat pump system 1 is configured to determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. The system 1 is further configured to automatically stop, or at least diminish, flow in the closed heating flow circuit 10. Hence, spreading of the primary fluid, e.g. the flammable constituent, through the closed heating flow circuit 10 can be minimized. The system 1 can be configured to automatically stop, or at least diminish, flow in the closed heating flow circuit 10 by stopping, or at least reducing pump speed of, the pump 14. Stopping the pump 14 can stop flow in the closed heating flow circuit 10. Stopping, or at least reducing speed of, the pump 14 can stop, or diminish, primary fluid, such as flammable constituent, leaked into the closed heating flow circuit 10 at the heat exchanger 8 from spreading through the closed heating flow circuit 10. The system 1 can be configured to automatically stop, or at least diminish, flow in the closed heating flow circuit 10 by closing the shut-off valve 38. Closing the shut-off valve 38 can stop primary fluid, such as flammable constituent, leaked into the closed heating flow circuit 10 at the heat exchanger 8 from spreading through the closed heating flow circuit 10.

[0084] Alternatively, or additionally, the system 1 can be configured to, in response to determining the risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, automatically opening the blow-off valve 40. Opening the blow-off valve 40 can allow primary fluid, such as flammable constituent, leaked into the closed heating flow circuit 10 at the heat exchanger 8 to escape from the closed heating flow circuit 10.

[0085] Alternatively, or additionally, system can be configured to, in response to determining the risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, automatically closing the vent 32 and / or preventing the vent 32 from opening. Thereto, the degassing device 20 can comprise a vent actuator and / or lock 31 Closing the vent 32 and / or preventing the vent 32 from opening can prevent, or at least diminish, gas, such as flammable constituent, escaping via the vent 32.

[0086] Alternatively, or additionally, the system 1 can be configured to, in response to determining the risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, automatically stop the compressor 17 of the heat pump 2. Stopping the compressor 17 can stop flow in the heat pump flow circuit 4, thereby stopping, or at least reducing leaking of the primary fluid, such as flammable constituent, into the closed heating flow circuit 10 at the heat exchanger 8. As shown in figure 3, the heat pump system 1 comprises a controller 42. It will be appreciated that the controller 42 and sensors 36i can be applied in the example of figure 1. The controller 42 can be configured to, in response to determining the risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, controlling the pump 14 for stopping, or at least reducing pump speed of, the pump 14. The controller 42 can be configured to, in response to determining the risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, controlling the shut-off valve 38 for closing the shut-off valve 38. The controller 42 can be configured to, in response to determining the risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, controlling the blow-off valve 40 for opening the blow-off valve 40. The controller 42 can be configured to, in response to determining the risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, controlling the vent 32 for opening closing the vent 32 and / or preventing the vent 32 from opening. The controller 42 can be configured to, in response to determining the risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, controlling the compressor 17 for stopping the compressor 17.

[0087] The controller 42 can be a controller of the degassing device 20. The controller 42 can be a controller of the heat pump 2. The controller 42 can be a controller of the heat pump system 1.

[0088] In the examples of figures 1-3, the heat pump system 1 is configured to determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1 on the basis of a signal provided by the sensor 36. It is possible that the controller 42 receives the signal provided by the sensor 36, and the controller 42 determines whether or not there is a risk of presence of a leak in the heat exchanger 8. The sensor 36 can be configured to transmit, e.g. to the controller 42, a signal representative of the measured value. The controller 42 can be configured to compare the measured value to a predetermined threshold value. It is also possible that the sensor 36 determines whether or not there is a risk of presence of a leak in the heat exchanger 8 and sends corresponding information to the controller. The sensor 36 can be configured to compare the measured value to a predetermined threshold value. The sensor 36 can be configured to transmit, e.g. to the controller 42, a signal in case the measured value exceeds the predetermined threshold value.

[0089] In a first example, the sensor comprises the gas flow sensor 36a configured to sense the gas flow through the vent 32. The controller 42, or the sensor 36a, can be configured to, in response to the sensor 36a detecting a gas flow through the vent 32 exceeding a first threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A high flow of gas through the vent 32 can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit 10 at the heat exchanger 8.

[0090] In a second example, the sensor comprises the gas flow sensor 36a configured to sense the gas flow through the vent 32. The controller 42, or the sensor 36a, can be configured to, in response to the sensor 36a detecting an increase rate in gas flow through the vent 32 exceeding a second threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A rapid increase in flow rate of gas through the vent 32 can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit 10 at the heat exchanger 8.

[0091] In a third example, the sensor comprises the pressure sensor 36b configured to sense the pressure in the housing 22. The controller 42, or the sensor 36b, can be configured to, in response to the sensor 36b detecting a pressure in the housing 22 exceeding a third threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A high pressure of gas in the housing 22 can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit 10 at the heat exchanger 8.

[0092] In a fourth example, the sensor comprises the pressure sensor 36b configured to sense the pressure in the housing 22. The controller 42, or the sensor 36b, can be configured to, in response to the sensor 36b detecting a pressure increase rate in the housing 22 exceeding a fourth threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A rapid increase in the pressure of gas in the housing can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit at the heat exchanger.

[0093] In a fifth example, the sensor comprises the secondary liquid level sensor 36c configured to sense the secondary liquid level in the housing 22. The controller 42, or the sensor 36c, can be configured to, in response to the sensor 36c detecting a secondary liquid level in the housing 22 exceeding, here dropping below, a fifth threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A low level of liquid in the housing 22 can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit 10 at the heat exchanger 8.

[0094] In a sixth example, the sensor comprises the secondary liquid level sensor 36c configured to sense the secondary liquid level in the housing 22. The controller 42, or the sensor 36c, can be configured to, in response to the sensor 36c detecting a secondary liquid level decrease rate in the housing 22 exceeding a sixth threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A rapid decrease of the liquid level in the housing 22 can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit 10 at the heat exchanger 8. In a seventh example, the sensor comprises the float sensor 36 d configured to sense the position and / or displacement of the float 34 in the housing 22. The controller 42, or the sensor 36d, can be configured to, in response to the sensor 36d detecting a position of the float 34 in the housing 22 exceeding, here dropping below, a seventh threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A low position of the float 34 in the housing 22 can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit 10 at the heat exchanger 8.

[0095] In an eighth example, the sensor comprises the float sensor 36d configured to sense the position and / or displacement of the float 34 in the housing 22. The controller 42, or the sensor 36d, can be configured to, in response to the sensor 36d detecting a displacement of the float 34 in the housing 22 exceeding an eighth threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A large displacement of the float 34 in the housing 22 can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit 10 at the heat exchanger 8.

[0096] In a ninth example, the sensor comprises the float sensor 36d configured to sense the position and / or displacement of the float 34 in the housing 22. The controller 42, or the sensor 36d, can be configured to, in response to the sensor 36d detecting a displacement rate of the float 34 in the housing 22 exceeding a ninth threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A rapid displacement of the float 34 in the housing 22 can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit 10 at the heat exchanger 8.

[0097] In a tenth example, the sensor comprises the temperature sensor 36e configured to sense the temperature in the housing 22, or at the vent 32. The controller 42, or the sensor 36e, can be configured to, in response to the sensor 36e detecting temperature in the housing 22, or at the vent 32, exceeding, here dropping below, a tenth threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A low temperature, in the housing 22, or at the vent 32, can be representative of a large amount of gas escaping at the vent, which can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit 10 at the heat exchanger 8.

[0098] In an eleventh example, the sensor comprises the temperature sensor 36e configured to sense the temperature in the housing 22, or at the vent 32. The controller 42, or the sensor 36e, can be configured to, in response to the sensor 36e detecting temperature change rate in the housing 22, or at the vent 32, exceeding an eleventh threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A rapid temperature change in the housing 22, or at the vent 32, can be representative of a large amount of gas escaping at the vent 32, which can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit 10 at the heat exchanger 8.

[0099] In a twelfth example, the sensor comprises the flammable gas content sensor 36f configured to sense the flammable gas content in the housing 22. The controller 42, or the sensor 36f, can be configured to, in response to the sensor 36f detecting flammable gas content in the housing 22 exceeding a twelfth threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A high flammable gas content in the housing 22 can be representative of primary fluid, such as flammable constituent, leaking into the closed heating flow circuit 10 at the heat exchanger 8.

[0100] In a thirteenth example, the sensor comprises the flammable gas content sensor 36f configured to sense the flammable gas content in the housing 22. The controller 42, or the sensor 36f, can be configured to, in response to the sensor 36f detecting flammable gas content change rate in the housing 22 exceeding a thirteenth threshold, determine that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. A high flammable gas content change rate in the housing 22 can be representative of gas leaking into the closed heating flow circuit 10 at the heat exchanger 8.

[0101] It will be clear that values for the first through thirteenth thresholds can be determined through routine experimentation, e.g. in a controlled environment such as a laboratory. In such experiment, a leak in the heat exchanger can be simulated by controlled insertion, e.g. via a valve, of primary fluid, or e.g. flammable constituent, into the secondary flow circuit. Measured values of the sensors 36 (e.g. 36a-36f) can e.g. be calibrated against controlled inflow (leak) of primary fluid, or e.g. flammable constituent, into the secondary flow circuit.

[0102] It will be appreciated that any of the first through thirteenth examples can be combined. Combining sensing according to two or more of the first through thirteenth examples can increase the accuracy of determining that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1. Figure 4 shows an example of a schematic flow chart of a method 200 for determining risk of presence of a leak in a heat exchanger of a heat pump system configured for heating a building. The method can e.g. be executed with a heat pump system 1 or a degassing device 20 as described in view of figures 1-3. The

[0103] In a first step 201, the method comprises determining the risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, on the basis of a signal provided by the sensor 36, such as by one or more of the gas flow sensor 36a, pressure sensor 36b, secondary liquid level sensor 36c, float sensor 36d, temperature sensor 36e, and flammable gas content sensor 36f. In the first step 201 the risk of presence of a leak in the heat exchanger 8 of the heat pump system 1 can be determined in case one or more of:

[0104] (i) the sensor 36a detects a gas flow through the vent exceeding the first threshold;

[0105] (ii) the sensor 36a detects an increase rate in gas flow through the vent exceeding the second threshold;

[0106] (iii) the sensor 36b detects a pressure in the housing exceeding the third threshold;

[0107] (iv) the sensor 36b detects a pressure increase rate in the housing exceeding the fourth threshold;

[0108] (v) the sensor 36c detects a secondary liquid level in the housing dropping below the fifth threshold;

[0109] (vi) the sensor 36c detects a secondary liquid level decrease rate in the housing exceeding the sixth threshold;

[0110] (vii) the sensor 36d detects a position of a float in the housing dropping below the seventh threshold;

[0111] (viii) the sensor 36d detects a displacement of the float in the housing exceeding the eighth threshold;

[0112] (ix) the sensor 36d detects a displacement rate of the float in the housing exceeding the ninth threshold;

[0113] (x) the sensor 36e detects a temperature in the housing, or at the vent, being below the tenth threshold.

[0114] (xi) the sensor 36e detects a temperature change rate in the housing, or at the vent, exceeding the eleventh threshold;

[0115] (xii) the sensor 36f detects a flammable gas content in the housing exceeding the twelfth threshold; and / or

[0116] (xiii) the sensor 36f detects a flammable gas content change rate in the housing exceeding the thirteenth threshold. If it has been determined that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, in an optional second step flow in the closed heating flow circuit 10 may be stopped, or at least diminished. Thereto, the pump 14 may be stopped, or a pump speed of the pump 14 may be reduced. Alternatively, or additionally, the shut-off valve 38 may, at least partially, be closed.

[0117] Alternatively, or additionally, if it has been determined that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, in the optional second step the blow-off valve 40 may be opened.

[0118] Alternatively, or additionally, if it has been determined that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, in the optional second step the vent 32 may be closed, and / or the event 32 may be prevented from opening.

[0119] Alternatively, or additionally, if it has been determined that there is a risk of presence of a leak in the heat exchanger 8 of the heat pump system 1, in the optional second step the compressor 17 may be stopped.

[0120] Herein, the invention is described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein, without departing from the essence of the invention. For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments, however, alternative embodiments having combinations of all or some of the features described in these separate embodiments are also envisaged.

[0121] However, other modifications, variations, and alternatives are also possible. The specifications, drawings and examples are, accordingly, to be regarded in an illustrative sense rather than in a restrictive sense.

[0122] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word ‘comprising’ does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words ‘a’ and ‘an’ shall not be construed as limited to ‘only one’, but instead are used to mean ‘at least one’, and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to an advantage.

Claims

Claims1. A method for determining risk of presence of a leak in a heat exchanger of a heat pump system configured for heating a building, the heat pump system comprising a heat pump having a heat pump flow circuit extending through a primary side of the heat exchanger and a closed heating flow circuit extending through a secondary side of the heat exchanger, and the heat pump system comprising a degassing device, comprising a housing having a fluid inlet port and a fluid outlet port for connection to the closed heating flow circuit, and a vent configured to be automatically opened for allowing gas to exit the closed heating flow circuit when an amount of gas present in the housing is more than a predetermined threshold amount, the degassing device comprising a sensor for sensing one or more of(a) a gas flow through the vent,(b) a pressure in the housing,(c) a gas volume in the housing,(d) a secondary liquid level in the housing,(e) a position and / or displacement of a float in the housing,(f) a temperature in the housing,(g) a temperature in the vent; the method comprising determining, on the basis of a signal provided by the sensor, the risk of presence of a leak in the heat exchanger of the heat pump system.

2. The method of claim 1, comprising determining a measured value of one or more of (a) the gas flow through the vent, (b) the pressure in the housing, (c) the gas volume in the housing, (d) the secondary liquid level in the housing, (e) the position and / or displacement of the float in the housing, (f) the temperature in the housing, (g) the temperature at the vent; anddetermining the risk of presence of a leak in the heat exchanger of the heat pump system on the basis of the measured value(s) provided by the sensor.

3. The method of claim 1 or 2, comprising, in response to determining the presence of a leak in the heat exchanger of the heat pump system, automatically stopping, or at least diminishing, flow in the closed heating flow circuit and / or the heat pump flow circuit.

4. The method of claim 3, wherein the closed heating flow circuit comprises a pump, e.g. upstream of the heat exchanger, and the method comprises automatically stopping, or at least diminishing, flow in the closed heating flow circuit by stopping, or at least reducing pump speed of, the pump.

5. The method of claim 3 or 4, wherein the heat pump system comprises a shut-off valve, e.g. in the closed heating flow circuit downstream of the heat exchanger and / or in the heat pump flow circuit, and the method comprises automatically at least partially, closing the shut-off valve.

6. The method of any of claims 1-5, wherein the closed heating flow circuit comprise a blow-off valve, and the method comprises, in response to determining the presence of a leak in the heat exchanger of the heat pump system, automatically opening the blow-off valve.

7. The method of any of claims 1-6, comprising, in response to determining the risk of presence of a leak in the heat exchanger of the heat pump system, automatically closing the vent and / or preventing the vent from opening.

8. The method of any of claims 1-6, comprising, in response to determining the risk of presence of a leak in the heat exchanger of the heat pump system, automatically stopping a compressor of the heat pump.

9. The method of any of claims 1-8, comprising determining the risk of presence of a leak in the heat exchanger of the heat pump system in case:(i) the sensor detects a gas flow through the vent exceeding a first threshold;(ii) the sensor detects an increase rate in gas flow through the vent exceeding a second threshold;(iii) the sensor detects a pressure in the housing exceeding a third threshold;(iv) the sensor detects a pressure increase rate in the housing exceeding a fourth threshold;(v) the sensor detects a secondary liquid level in the housing dropping below a fifth threshold;(vi) the sensor detects a secondary liquid level decrease rate in the housing exceeding a sixth threshold;(vii) the sensor detects a position of a float in the housing dropping below a seventh threshold;(viii) the sensor detects a displacement of the float in the housing exceeding an eighth threshold;(ix) the sensor detects a displacement rate of the float in the housing exceeding a ninth threshold;(x) the sensor detects a temperature in the housing, or at the vent, being below a tenth threshold; and / or(xi) the sensor detects a temperature change rate in the housing, or at the vent, exceeding an eleventh threshold;10. The method of any of claims 1-9, wherein the determining the risk of presence of a leak in the heat exchanger of the heat pump system is performed by the sensor.

11. The method of claim 10, wherein the sensor transmits a command to stop, or at least diminishing, flow in the closed heating flow circuit, such as by stopping, or at least reducing pump speed of, the pump; and / or a command to close the shut-off valve; and / or a command to open the blow-off valve; and / or a command to close the vent and / or prevent the vent from opening; and / or a command to stop the compressor.

12. The method of any of claims 1-11, comprising the sensor transmitting a signal to a controller, wherein the determining the risk of presence of a leak in the heat exchanger of the heat pump system is performed by the controller.

13. The method of claim 10 or 12, wherein the controller transmits a command to stop, or at least diminishing, flow in the closed heating flow circuit, such as by stopping, or at least reducing pump speed of, the pump; and / or a command to close the shut-off valve; and / or a command to open the blow-off valve; and / or a command to close the vent and / or prevent the vent from opening; and / or a command to stop the compressor.

14. A heat pump system for heating a building comprising: a heat pump having a heat pump flow circuit extending through a primary side of a heat exchanger; a closed heating flow circuit extending through a secondary side of the heat exchanger; a degassing device in the closed heating flow circuit, the degassing device comprising:a housing having a fluid inlet port and a fluid outlet port for connection to the closed heating flow circuit, the housing forming an internal chamber; a vent configured to be automatically opened for allowing gas to exit the closed heating flow circuit when an amount of gas present in the housing is more than a predetermined threshold amount; a sensor for sensing one or more of (a) a gas flow through the vent, (b) a pressure in the housing, (c) a gas volume in the housing, (d) a secondary liquid level in the housing, (e) a position and / or displacement of a float in the housing, (f) a temperature in the housing, (g) a temperature in the vent; and a controller connected to the sensor and configured to stop, or at least diminish, flow in the closed heating flow circuit and / or the heat pump flow circuit, based on input received from the sensor.

15. The heat pump system of claim 14, wherein the closed heating flow circuit comprises a pump and / or a blow-off valve.

16. The heat pump system of claim 14 or 15, comprising a shut-off valve in the closed heating flow circuit and / or in the heat pump flow circuit.

17. The heat pump system of claim 15, or claim 16 as far as dependent from claim 15, wherein the controller is configured to stop, or at least slow down, the pump based on the input received from the sensor.

18. The heat pump system of claim 16, or claim 17 as far as dependent from claim 16, wherein the controller is configured to close, at least partially, the shut-off valve based on the input received from the sensor.

19. The heat pump system of any of claims 15-18, wherein the controller is configured to open, at least partially, the blow-off valve based on the input received from the sensor.

20. The heat pump system of any of claims 14-19, wherein the controller is configured to close the vent, and / or prevent the vent from opening, based on the input received from the sensor.

21. The heat pump system of any of claims 14-20, wherein the controller is configured to stop a compressor of the heat pump, based on the input received from the sensor.

22. The heat pump system of any of claims 14-21, wherein the controller is configured to stop, or at least diminish, flow in closed heating flow circuit and / or the heat pump flow circuit in response to (i) the sensor detecting a gas flow through the vent exceeding a first threshold, (ii) the sensor detecting an increase rate in gas flow through the vent exceeding a second threshold, (iii) the sensor detecting a pressure in the housing exceeding a third threshold, (iv) the sensor detecting a pressure increase rate in the housing exceeding a fourth threshold, (v) the sensor detecting a secondary liquid level in the housing dropping below a fifth threshold, (vi) the sensor detecting a secondary liquid level decrease rate in the housing exceeding a sixth threshold, (vii) the sensor detecting a position of a float in the housing dropping below a seventh threshold, (viii) the sensor detecting a displacement of the float in the housing exceeding an eighth threshold, (ix) to the sensor detecting a displacement rate of the float in the housing exceeding a ninth threshold, (x) the sensor detecting a temperature in the housing, or at the vent, being below a tenth threshold, and / or (xi) the sensor detecting a temperature change rate in the housing, or at the vent, exceeding an eleventh threshold.

23. The heat pump system of claim 15, or any of claim 16-22 as far as dependent from claim 15, wherein the pump is configured to automatically stop when a flow in the closed heating flow circuit is below a predetermined threshold.

24. The heat pump system of claim 16, or any of claims 17-23 as far as dependent from claim 16, wherein the shut-off valve is positioned in the closed heating flow circuit downstream of the heat exchanger and upstream of the degassing device.

25. The heat pump system of claim 15, or any of claims 16-24 as far as dependent from claim 15, wherein the blow-off valve is positioned in the closed heating flow circuit downstream of the heat exchanger and upstream of the degassing device.

26. The heat pump system of claim 15, or any of claims 16-25 as far as dependent from claim 15, wherein a flow capacity of the blow-off valve larger than a flow capacity of the vent.

27. The heat pump system of claim 15, or any of claims 16-26 as far as dependent from claim 15, wherein the blow-off valve blows off gas to an outside of the building.

28. The heat pump system of any of claims 14-27, wherein the degassing device is placed on an outlet pipe of the secondary side of the heat exchanger.

29. The heat pump system of any of claims 14-28, wherein the vent comprises a valve and a float for automatically opening the valve for allowing gas to exit the housing when the amount of gas present in the housing is more than the predetermined threshold amount.

30. The heat pump system of any of claims 14-29, wherein the degassing device comprises a pressure relief valve configured to be automatically opened for allowing gas to exit the closed heating flow circuit when a pressure of gas present in the housing is higher than a predetermined threshold pressure.

31. The heat pump system of any of claims 14-30, wherein the internal chamber includes a flow stabilizer.

32. The heat pump system of any of claims 14-31, wherein a medium circulating through the heat pump flow circuit is flammable, and a medium circulating through the closed heating flow circuit is non-flammable.

33. A degassing device, for a heat pump system for heating a building comprising a heat pump having a heat pump flow circuit extending through a primary side of a heat exchanger and a closed heating flow circuit extending through a secondary side of the heat exchanger, the degassing device comprising: a housing having a fluid inlet port and a fluid outlet port for connection to the closed heating flow circuit, the housing forming an internal chamber; a vent configured to be automatically opened for allowing gas to exit the closed heating flow circuit when an amount of gas present in the housing is more than a predetermined threshold amount; and a sensor for sensing one or more of (a) a gas flow through the vent, (b) a pressure in the housing, (c) a gas volume in the housing, (d) a secondary liquid level in the housing, (e) a position and / or displacement of a float in the housing, (f) a temperature in the housing, (g) a temperature at the vent;the sensor being configured for providing, such as to a controller, a signal configured to stop, or at least diminish, flow in the closed heating flow circuit and / or the heat pump flow circuit.

34. The degassing device of claim 33, further comprising the controller.

35. The degassing device of claim 33 or 34, wherein the controller is configured to control a pump and / or a blow-off valve of the closed heating flow circuit.

36. The degassing device of claim 33, 34 or 35, wherein the controller is configured to control a shut-off valve in the closed heating flow circuit and / or in the heat pump flow circuit.

37. The degassing device of claim 35 or 36, further comprising the blow-off valve and / or the shut-off valve.

38. The degassing device of any of claims 33-37, comprising a pressure relief valve configured to be automatically opened for allowing gas to exit the housing when a pressure of gas present in the housing is higher than a predetermined threshold pressure.

39. The degassing device of claim 38, wherein the pressure relief valve is positioned above a liquid level in the degassing device.

40. The degassing device of any of claims 33-39, wherein the degassing device is configured to provide the signal configured to stop, or at least diminish, flow in the closed heating flow circuit and / or the heat pump flow circuit, in response to (i) the sensor detecting a gas flow through the vent exceeding a first threshold, (ii) the sensor detecting an increase rate in gas flow through the vent exceeding a second threshold, (iii) the sensor detectinga pressure in the housing exceeding a third threshold, (iv) the sensor detecting a pressure increase rate in the housing exceeding a fourth threshold, (v) the sensor detecting a secondary liquid level in the housing dropping below a fifth threshold, (vi) the sensor detecting a secondary liquid level decrease rate in the housing exceeding a sixth threshold, (vii) the sensor detecting a position of a float in the housing dropping below a seventh threshold, (viii) the sensor detecting a displacement of the float in the housing exceeding an eighth threshold, (ix) to the sensor detecting a displacement rate of the float in the housing exceeding a ninth threshold, (x) the sensor detecting a temperature in the housing, or at the vent, being below a tenth threshold, and / or (xi) the sensor detecting a temperature change rate in the housing, or at the vent, exceeding an eleventh threshold.

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