Air-water heat pump and associated method

Abstract

The present invention relates to an air-to-water heat pump (1) comprising an evaporator chamber (2), a cold chamber (3), a refrigerant circuit (20), and a controller for controlling the air-to-water heat pump (1). The air-to-water heat pump (1) comprises, in the evaporator chamber (2), an evaporator (12) and a fan (10) designed to guide air over the evaporator (12); and the air-to-water heat pump (1) comprises, in the cold chamber (3), a compressor and a condenser (22); a connection (16) exists between the cold chamber (3) and the evaporator chamber (2), and a safety fan (17) is arranged in the connection (16), such that a negative pressure is maintained in the cold chamber (3) by the operation of the safety fan. The invention also relates to a related method.

Description

[0001] The present invention relates to an air-water heat pump and a method for operating an air-water heat pump.

[0002] For air-to-water heat pumps, especially those installed indoors, the increased use of highly flammable, combustible, and / or harmful refrigerants is resulting in new safety requirements. In particular, it is important to prevent such refrigerants from leaking into the air-to-water heat pump's installation room. This installation room could be a boiler room, a utility room, or a basement.

[0003] If a fault occurs, i.e., refrigerant leaks from the refrigerant circuit of the air-to-water heat pump, it must be transported to a non-critical area, for example, outside the building where the installation room is located. Alternatively, the installation room must exceed a certain minimum volume, which is usually not possible in practice due to the significantly smaller installation rooms.

[0004] Solutions for this are known, for example, from DE 10 2019 001 637 A1. However, the known solutions do not provide sufficient safety for discharging the refrigerant to a non-critical area.

[0005] Against this background, it was an object of the present invention to provide an air-water heat pump that enables safe operation with highly flammable, combustible and / or health-damaging refrigerants.

[0006] The object is achieved according to the invention by the independent claims. Preferred embodiments are specified in the subclaims.

[0007] In one embodiment, an air-water heat pump is proposed which has an evaporator chamber, a cold chamber, a refrigerant circuit and a controller for controlling the air-water heat pump, wherein the air-water heat pump has in the evaporator chamber: an evaporator and a fan which is configured to guide air over the evaporator.

[0008] The air-water heat pump has a compressor and a condenser in the cold room, with a connection between the cold room and the evaporator room.

[0009] According to the invention, a safety fan is arranged in the connection in such a way that a negative pressure is maintained in the cold room by the operation of the safety fan.

[0010] The safety fan is therefore used to ensure the permanent removal of any leaking refrigerant. The air-to-water heat pump according to the invention enables a safety concept that prevents flammable, combustible, and / or harmful refrigerant from escaping into the room where the air-to-water heat pump is installed.

[0011] The negative pressure in the cold room ensures that any leaking refrigerant is vented to the installation room through the fan and not through other openings in the cold room. The cold room must be sealed accordingly to allow this negative pressure to occur. Preferably, the connection between the cold room and the evaporator chamber, where the safety fan is located, is the cold room's only opening to the outside.

[0012] Preferably, the control system of the air-to-water heat pump is configured to operate the fan continuously. The fan, which is typically present in an air-to-water heat pump to direct air over the evaporator, is thus used to simultaneously ensure the continuous removal of any escaping refrigerant. To this end, the control system, which previously switched off the fan when the air-to-water heat pump was not in operation, is modified so that the fan operates continuously.

[0013] Preferably, the control is designed to operate the fan even when the air-water heat pump is not absorbing any ambient energy, in particular even when the compressor of the air-water heat pump is not operating and / or the air-water heat pump is in a switched-off operating state.

[0014] Preferably, the air-water heat pump further comprises a safety unit, wherein the safety unit is designed to monitor a negative pressure in the cold room.

[0015] The safety unit can therefore control the operation of the safety fan depending on the monitored negative pressure. Without a safety unit, it is preferable for the safety fan to operate continuously.

[0016] Conventional methods include monitoring refrigerant leaks using pressure cells and detecting leaks when overpressure occurs. As long as the fan or safety ventilator is running—that is, as long as the safety unit detects a negative pressure in the cold room—the safety of the air-to-water heat pump is guaranteed, since the running fan or safety ventilator ensures the removal of any leaking refrigerant.

[0017] In the event of a fault, for example, if insufficient negative pressure is detected and the fan speed is increased beyond the value required to maintain the heat pump's functionality, the safety unit can send a signal to another unit so that maintenance can be carried out on the air-to-water heat pump. There are no limits to the transmission of this signal. The signal can be sent wired or wirelessly to a control element on the air-to-water heat pump itself, or directly and / or via a server to a mobile device such as a smartphone.

[0018] Preferably, the safety unit comprises a differential pressure switch for monitoring the negative pressure in the cold room.

[0019] The differential pressure switch is preferably designed to detect a differential pressure between the environment outside the cold room and the interior of the cold room, for example via measuring hoses.

[0020] Preferably, the control is designed to increase a speed of the fan of the air-water heat pump, in particular to 60%, 70%, 80%, 90% and / or to increase a maximum speed of the fan, depending on the monitored negative pressure.

[0021] Preferably, the control system is configured to operate the safety fan continuously. This ensures maximum safety for the air-to-water heat pump, while the impact of the low-power safety fan on efficiency is minimal.

[0022] Preferably, the controller is configured to selectively operate the safety fan depending on a monitored negative pressure in the cold room. This can increase the service life of the safety fan. Furthermore, the efficiency of the heat pump can be further improved, since no unnecessary energy is consumed to operate the fan. For example, the controller can operate the safety fan when the negative pressure in the cold room created by the operation of the fan is insufficient.

[0023] In one embodiment, the refrigerant circuit contains a flammable, combustible, and / or harmful refrigerant. When using such refrigerants, the safety concept developed according to the invention is particularly advantageous. Safe discharge of the refrigerant is ensured even if it leaks from the refrigerant circuit. Preferably, the refrigerant comprises R290, although the use of other refrigerants is also possible.

[0024] The air-to-water heat pump is preferably designed as an indoor air-to-water heat pump. With indoor heat pumps, the flammability of escaping refrigerant is particularly serious.

[0025] Preferably, the air-water heat pump has an air duct adjacent to the fan for discharging air from the installation room, wherein in particular refrigerant escaping from the refrigerant circuit is discharging from the installation room by, for example, the permanent operation of the safety fan.

[0026] In one embodiment, the controller is configured to reduce the fan speed when the air-to-water heat pump is in a deactivated operating state. Particularly preferably, it is sufficient to operate the safety fan and thereby maintain the negative pressure. Then, it is also possible to reduce the fan speed to zero to further reduce power consumption.

[0027] By reducing the fan speed when the air-to-water heat pump is off, the standby power consumption of the air-to-water heat pump is reduced to a low value. For example, power consumption in standby mode, i.e., when the heat pump is off, can be kept below 4 watts, including fan operation and, preferably, the power consumption of power electronics such as inverters.

[0028] In a further aspect, a method for operating an air-to-water heat pump is proposed. The air-to-water heat pump has an evaporator chamber, a cold chamber, a refrigerant circuit, and a controller for controlling the air-to-water heat pump. The air-to-water heat pump has, in the evaporator chamber, an evaporator and a fan configured to guide air over the evaporator. The air-to-water heat pump has, in the cold chamber, a compressor and a condenser. A connection exists between the cold chamber and the evaporator chamber, and a safety fan is arranged in the connection. The method comprises operating the safety fan to maintain a negative pressure in the cold chamber.

[0029] Further advantages and preferred embodiments are described below with reference to the attached figures. Herein: Fig. 1schematic and exemplary perspective view of an air-water heat pump and Fig. 2 schematic and exemplary side view of the air-water heat pump from Fig. 1 .

[0030] Fig. 1 shows schematically and exemplarily a perspective view of an air-water heat pump 1 according to the invention. The air-water heat pump 1 is not shown in its entirety, but in part, wherein a fan 10, which is designed to guide air over an evaporator 12, is arranged in an evaporator chamber 2. Below the evaporator chamber 2 there is a cooling chamber 3, which is described below with reference to Fig. 2 is described in detail.

[0031] The fan 10 is preferably designed to direct air out of the installation room, which may be, for example, a boiler room, a utility room or a basement room, via a duct (not shown).

[0032] The evaporator 12 is part of the refrigerant circuit, with the essential remaining components of the refrigerant circuit being arranged in the cold room 3 (cf. Fig. 2 ).

[0033] The air-to-water heat pump 1 is divided into two compartments, the evaporator compartment 2 and the cold compartment 3. A defrost tray 14, designed to collect condensate during defrosting of the evaporator 12, essentially defines the separation between the two compartments. An air duct 16, shown schematically in the area of ​​the fan 10, establishes a connection between the cold compartment 3 and the evaporator compartment 2. Once the cold compartment 3 is sealed, with the exception of the air duct 16, operation of the fan 10 creates a negative pressure in the cold compartment 3. This allows refrigerant, for example, flammable, combustible, and / or harmful refrigerant such as R290, which escapes in the event of a fault, to be reliably transported from the device to a non-critical area, for example, outside the building.

[0034] Fig. 2 shows schematically and exemplarily a side view of the already in Fig. 1shown air-water heat pump 1. The cold room 3 is shown without a side cover so that the internal components are visible.

[0035] The air duct 16 is preferably the only connection between the evaporator chamber 2 and the cold room 3. The cold room 3 is sealed with the exception of the air duct 16. A safety fan 17 is arranged in the air duct 16. The operation of the safety fan 17 allows a negative pressure to be built up in the cold room 3. The negative pressure in the cold room 3 makes it possible to transport any escaping refrigerant from the cold room 3 into the evaporator chamber 2 and then out of the installation room, thus eliminating the risk of ignition of the flammable refrigerant.

[0036] The refrigerant circuit is schematically identified by reference numeral 20 and comprises, for example, a compressor and a condenser 22. Advantageously, in the area of ​​the cold room 3, connections 32 are provided on the outside or in the cold room 3 of the air-water heat pump, which connections enable the air-water heat pump 1 to be connected to a power supply and / or heating circuits or domestic water circuits. In the side view of the Fig. 2 The condensate or defrost tray 14 is also clearly visible.

[0037] A flow path through the air duct 16 is schematically indicated by an arrow 18. From the cold room 3, this flow enters the fan 10 through the air duct 16 and the safety fan 17 and is thereby expelled from the installation room.

[0038] Thus, a Fig. 1 and Fig. 2A safety fan 17 operated by the air-water heat pump control (not shown) is proposed for discharging refrigerant to the outside air.

[0039] The extraction concept covers every part of the refrigerant circuit 20, so that any escaping refrigerant can be reliably led to the outside from any position.

[0040] A safety unit 23 is also provided, which includes a differential pressure switch 24. The differential pressure switch 24 monitors a negative pressure in the cold room 3 by comparing a pressure applied to a measuring hose 26 inside the cold room 3 with a pressure applied to a measuring hose 28 in the installation room.

[0041] A negative pressure in the cold room 3 is maintained by the safety fan 17. The operation of the fan 10 supports the generation of the negative pressure. The safety fan 17 can be operated continuously or, alternatively, can be activated whenever, for example, the speed of the fan 17 is insufficient to maintain a sufficient negative pressure in the cold room 3.

[0042] In other words, the safety fan 17 can be solely responsible for the negative pressure in the cold room 3. Alternatively or additionally, the fan 10 can provide support. List of reference symbols

[0043] 1 Air-to-water heat pump 2 Evaporator chamber 3 Cold room 10 Fan 12 Evaporator 14 Defrost tray 16 Air duct 17 Safety fan 20 Refrigerant circuit 22 Condenser 23 Safety unit 24 Differential pressure switch 26 Measuring hose in the cold room 28 Measuring hose in the installation room 32 Connections

Claims

1. An air-to-water heat pump (1) comprising an evaporator chamber (2), a cold chamber (3), a refrigerant circuit (20), and a controller for controlling the air-to-water heat pump (1), wherein the air-to-water heat pump (1) comprises in the evaporator chamber (2): - an evaporator (12) and - a fan (10) configured to direct air over the evaporator (12), and the air-to-water heat pump (1) comprises in the cold chamber (3): - a compressor and - a condenser (22), wherein a connection (16) exists between the cold chamber (3) and the evaporator chamber (2), characterized in that a safety fan (17) is arranged in the connection (16) such that a negative pressure is maintained in the cold room (3) by the operation of the safety fan.

2. Air-water heat pump (1) according to claim 1, wherein the control of the air-water heat pump (1) is designed to operate the fan (10) permanently.

3. Air-water heat pump (1) according to one of the preceding claims, wherein the controller is designed to operate the fan (10) even when the air-water heat pump (1) is not absorbing any ambient energy, in particular even when the compressor of the air-water heat pump (1) is not operating and / or the air-water heat pump (1) is in a switched-off operating state.

4. Air-water heat pump (1) according to one of the preceding claims, further comprising a safety unit (23), wherein the safety unit (23) is designed to monitor a negative pressure in the cold room (3).

5. Air-water heat pump (1) according to claim 4, wherein the safety unit (23) has a differential pressure switch (24) for monitoring the negative pressure in the cold room (3).

6. Air-water heat pump (1) according to claim 4 or 5, wherein the control is designed to increase a speed of the fan (10) of the air-water heat pump (1) as a function of the monitored negative pressure, in particular to 60%, 70%, 80%, 90% and / or to increase a maximum speed of the fan (10).

7. Air-water heat pump (1) according to one of the preceding claims, wherein the control is designed to operate the safety fan (17) permanently.

8. Air-water heat pump (1) according to one of the preceding claims 1 to 6, wherein the control is designed to operate the safety fan (17) selectively as a function of a monitored negative pressure in the cold room (3).

9. Air-water heat pump (1) according to one of the preceding claims, wherein the refrigerant circuit (20) comprises a flammable, combustible and / or health-damaging refrigerant, in particular R290.

10. Air-to-water heat pump (1) according to one of the preceding claims, wherein the air-to-water heat pump (1) is designed as an indoor air-to-water heat pump (1), wherein the air-to-water heat pump (1) in particular has an air duct adjacent to the fan (10) for discharging air from the installation room, wherein in particular refrigerant escaping from the refrigerant circuit (20) is discharging from the installation room by the permanent operation of the safety fan (17) and optionally the operation of the fan (10).

11. A method for operating an air-to-water heat pump (1) having an evaporator chamber (2), a cold chamber (3), a refrigerant circuit (20), and a controller for controlling the air-to-water heat pump (1), wherein the air-to-water heat pump (1) in the evaporator chamber (2) has: - an evaporator (12) and - a fan (10) configured to guide air over the evaporator (12), and the air-to-water heat pump (1) in the cold chamber (3) has: - a compressor and - a condenser (22), wherein a connection (16) exists between the cold chamber (3) and the evaporator chamber (2), wherein a safety fan is arranged in the connection (16), characterized in that the method comprises operating the safety fan (17) to maintain a negative pressure in the cold room (3).

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