Heat pump and method for detecting a leak in a heat pump

Abstract

The invention relates to a heat pump and a method for detecting a leak in a heat pump, comprising a heat pump component (2) which is arranged at least partially in a detection chamber (1) and carries a refrigerant. The detection chamber (1) is provided with a vibration-sensitive sensor (3) and a gas is provided surrounding the heat pump component (2). According to the invention, the speed of sound of the surrounding gas is at least 10% greater than the speed of sound of the refrigerant in the event of a leak of the refrigerant from the heat pump component (2) into the detection chamber (1).

Description

The invention relates to a heat pump according to the preamble of claim 1 and to a method for detecting a leak at a heat pump according to the preamble of claim 8.A heat pump and a method of the type mentioned at the beginning are known from patent document JP 2000249435 A. Viewed from the subject matter, this heat pump consists of a heat pump component which is arranged at least partially in a detection space and conducts a refrigerant, wherein the detection space is provided with a vibration-sensitive sensor and a gas surrounding the heat pump component is provided. Viewed in terms of the method, this solution uses a heat pump component for guiding a refrigerant. Furthermore, the heat pump component arranged at least partially in a detection space is surrounded by a gas in this detection space. In addition, a vibration-sensitive sensor is used for detecting a leakage of the refrigerant from the heat pump component into the detection space.The object of the invention is to improve such a heat pump or such a method. In particular, a heat pump or a method is to be created with which a leakage of the refrigerant can be detected even more specifically or more safely.This object is achieved with a heat pump of the type mentioned at the beginning or with a method of the type mentioned at the beginning by the features specified in the characterizing part of patent claims 1 and 8, respectively.According to the invention, it is therefore provided according to the subject matter that a sound velocity of the surrounding gas in the event of a leakage of the refrigerant from the heat pump component into the detection space and in particular at a temperature in the range from 5° C. to 30° C., particularly preferably at a temperature of 20° C., is at least 10% greater than a sound velocity of the refrigerant. Viewed in terms of the method, it is provided according to the invention that a gas is used as the surrounding gas, the speed of sound of which is at least 10% greater than a speed of sound of the refrigerant in the event of a leakage of the refrigerant from the heat pump component into the detection space and in particular at a temperature in the range from 5° C. to 30° C., particularly preferably at a temperature of 20° C.In other words, the heat pump according to the invention or the method according to the invention is thus distinguished in that, in the event of a leakage of the refrigerant, a significantly changed speed of sound occurs in the mixture of gas and refrigerant then formed in comparison with the pure surrounding gas, which in turn can be detected in a significantly more reliable manner than if the gas and the refrigerant, as in the prior art mentioned at the beginning, at least have similar speeds of sound during mixing.Other advantageous developments of the heat pump according to the invention or of the method according to the invention for detecting a leak are evident from the dependent patent claims.The heat pump according to the invention or the method according to the invention, including its advantageous developments according to the dependent patent claims, is explained in more detail below with reference to the graphic representation of a preferred exemplary embodiment.It shows FIG. 1 schematically shows the heat pump according to the invention with the detection space filled with a special gas.The heat pump illustrated in FIG. 1 consists of a heat pump component 2 which is arranged at least partially (or preferably also completely) in a detection space 1 and conducts a refrigerant, wherein the detection space 1 is provided with a vibration-sensitive sensor 3 and a gas surrounding the heat pump component 2 is provided. The heat pump component 2 is preferably a compressor of the heat pump, but other components of a or of the corresponding refrigerant circuit 7 are also possible, for example an expansion device or a heat exchanger. In this case, it is preferably provided that the refrigerant circuit 7, in particular its heat exchanger, is configured to be fluidically connected to a heating circuit via elastic hoses, in particular via EPDM hoses. Expressed again in other words according to the method, in this heat pump, one or the heat pump component 2 is used for guiding a or the refrigerant, wherein the heat pump component 2 arranged at least partially in one or in the detection space 1 is surrounded by a or by the gas in this detection space 1 and wherein a or the vibration-sensitive sensor 3 is used for detecting a leakage of the refrigerant from the heat pump component 2 into the detection space 1.Particularly preferably, propane (also referred to as R290) is provided as the refrigerant or propane is used as the refrigerant.Expressed first of all, it is essential for this heat pump that a sound velocity of the surrounding gas in the event of a leakage of the refrigerant from the heat pump component 2 into the detection space 1 and in particular at a temperature in the range from 5° C. to 30° C., particularly preferably at a temperature of 20° C., is at least 10%, preferably more than 50%, particularly preferably more than 200%, greater than a sound velocity of the refrigerant. Expressed in terms of the method, it is provided as essential for detecting a leak at the heat pump that a gas is used as the surrounding gas, the speed of sound of which gas is at least 10%, preferably more than 50%, particularly preferably more than 200%, greater than a speed of sound of the refrigerant in the event of a leak of the refrigerant from the heat pump component 2 into the detection space 1 and in particular at a temperature in the range from 5° C. to 30° C., particularly preferably at a temperature of 20° C.Viewed even more precisely, helium is particularly preferably provided as the gas or helium is particularly preferably used as said gas, which has a sound velocity of 981 m / s at 20° C. However, other gases are also possible, wherein it is furthermore preferably provided that the gas is inert or that an inert gas is used. This has the great advantage that it cannot react with the possibly leaked refrigerant.Furthermore, it is preferably provided that the vibration-sensitive sensor 3 is arranged in a lower region of the detection space 1. This is advantageous because propane, which is heavier than air and in particular also heavier than the gas provided according to the invention, would collect at the bottom in the detection space 1 in the event of a leak, and the monitoring function according to the invention would therefore still be ensured.It is also preferably provided that the vibration-sensitive sensor 3 is optionally designed as a microphone, in particular for detecting airborne sound, or as an accelerometer, in particular for detecting structure-borne sound. The sensor 3 can be arranged optionally in the detection space 1 but also outside the detection space 1, in the latter case of course in the vicinity thereof, i.e. such that oscillations can be detected with the sensor 3, i.e. preferably at most 50 cm away from the detection space 1.As is clearly shown in FIG. 1, it is furthermore preferably provided that the detection space 1 forms a space within an outer housing 11 of the heat pump. It is further particularly preferably provided that this space forms the so-called machine space of the heat pump, and is particularly preferably provided with a stiffened base plate.Furthermore, it is preferably provided that the detection space 1 is optionally sealed in a gas-tight manner (thus the exemplary embodiment according to FIG. 1 ) or at least is formed through which the gas flows (not shown separately). In the latter case, which is more complicated than conceivable, a correspondingly designed gas circulation device is provided in order to keep the detection space 1 always sufficiently flooded with gas. In the case of the gas-tight construction shown in FIG. 1, a gas pressure compensation chamber 9 which can be selectively connected or is connected to the detection chamber 1 is preferably provided for compensating possible volume changes of the gas within the detection chamber 1. Furthermore, for optionally required refilling of the detection chamber 1, an additional reservoir 10 filled with the gas and connectable to the detection chamber 1 is preferably provided.Furthermore, in all of these, it is preferably provided that a refrigerant circuit 7 carrying the refrigerant is arranged completely in the detection chamber 1. This advantageously allows leakage monitoring of the entire heat pump.In order to avoid necessarily relying on the noise of the heat pump component 2 during the planned monitoring of a possible leak, an additional sound source 4, preferably an ultrasonic transmitter operating outside the listening area of the person, is also particularly preferably provided in addition to the heat pump component 1 for emitting a reference signal. The advantage of this additional sound source 4 is in particular that it emits a precisely defined and also constant frequency, which simplifies the analysis of the recorded data.With regard to the aforementioned analysis, it is furthermore preferably provided that the vibration-sensitive sensor 3 is connected to an evaluation unit 5 and the evaluation unit 5 is connected to an output unit 6 for outputting a signal in the event of a leakage of the refrigerant from the heat pump component 2 into the detection chamber 1. Expressed in terms of the method and also considered somewhat more precisely, it is correspondingly preferably provided that the oscillations which are detected by the oscillation-sensitive sensor 3 are selectively detected by the heat pump component 2 and / or by the additional sound source 4 and the oscillations which are detected by the oscillation-sensitive sensor 3 are evaluated by an evaluation unit 5 and compared with previously detected and stored data.In this case, it is also preferably provided that the detection of the oscillations takes place at predetermined times and that optionally two successive detections or even an entire series of detections are compared with one another.In this case, it is also preferably provided that during the evaluation a current frequency spectrum is compared with a previously recorded and stored frequency spectrum and a signal is generated in the event of a change optionally in the frequency position and / or the frequency amplitude of the frequency spectra compared with one another. In this case, it is also particularly preferably provided that the generated signal is optionally used to influence the operation of the heat pump (for example "emergency off") and / or is transmitted to a terminal device such as a smartphone, laptop or the like of an operator of the warm pump in order to inform the latter about the detected leakage.For further analyses, it is finally also provided that an additional sensor 8 for measuring optionally the temperature, the pressure and / or the density of the gas in the detection chamber 1 is arranged in the detection chamber 1.List of reference characters1 Detection chamber 2 Heat pump component 3 Sensor 4 Additional sound source 5 Evaluation unit 6 Output unit 7 Refrigerant circuit 8 Additional sensor 9 Gas pressure compensation chamber 10 Additional reservoir 11 Outer housingReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP 2000249435 A

[0002]

Claims

A heat pump comprising a heat pump component (2) arranged at least partially in a detection space (1) and carrying a refrigerant, wherein the detection space (1) is provided with a vibration-sensitive sensor (3) and a gas surrounding the heat pump component (2) is provided, characterized in that a sound speed of the surrounding gas is at least 10% greater than a sound speed of the refrigerant in the event of a leakage of the refrigerant from the heat pump component (2) into the detection space (1).Heat pump according to claim 1, characterised in that the vibration-sensitive sensor (3) is optionally designed as a microphone or as an accelerometer.Heat pump according to Claim 1 or 2, characterized in that, in addition to the heat pump component (1), an additional sound source (4) is provided for emitting a reference signal.Heat pump according to one of Claims 1 to 3, characterized in that the vibration-sensitive sensor (3) is connected to an evaluation unit (5) and the evaluation unit (5) is connected to an output unit (6) for outputting a signal in the event of a leakage of the refrigerant from the heat pump component (2) into the detection space (1).Heat pump according to one of Claims 1 to 4, characterized in that a refrigerant circuit (7) which conducts the refrigerant is arranged completely in the detection space (1).Heat pump according to one of Claims 1 to 5, characterized in that propane is provided as refrigerant.Heat pump according to one of Claims 1 to 6, characterized in that helium is provided as the gas.Method for detecting a leak in a heat pump, in which a heat pump component (2) is used for guiding a refrigerant, in which the heat pump component (2) arranged at least partially in a detection space (1) is surrounded by a gas in this detection space (1), and in which a vibration-sensitive sensor (3) is used for detecting a leak of the refrigerant from the heat pump component (2) into the detection space (1), characterized in that a gas is used as the surrounding gas, the speed of sound of which is at least 10% greater than a speed of sound of the refrigerant in the event of a leak of the refrigerant from the heat pump component (2) into the detection space (1).Method according to Claim 8, characterized in that oscillations emitted by the heat pump component (2) are detected by the oscillation-sensitive sensor (3), and the oscillations detected by the oscillation-sensitive sensor (3) are evaluated by an evaluation unit (5) and compared with previously detected and stored data.Method according to claim 9, characterised in that during the evaluation a current frequency spectrum is compared with a previously recorded and stored frequency spectrum and a signal is generated in the event of a change optionally in the frequency position and / or the frequency amplitude of the frequency spectra compared with one another.Method according to claim 9 or 10, characterised in that the detection of the oscillations takes place at predetermined times and that optionally two successive detections or also an entire series of detections are compared with one another directly.Method according to claim 10, characterised in that the signal is used selectively to influence the operation of the heat pump and / or is transmitted to a terminal device such as smartphone, laptop or the like of an operator of the heat pump.

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