Valve for a refrigerant circuit, valve assembly, and heat pump

Abstract

The invention relates to a valve (100) for a refrigerant circuit, in particular for a refrigerant circuit of a heat pump, to a valve assembly, and to a heat pump. The invention additionally relates to a method for operating a valve (100) for a refrigerant circuit, to a computing unit, and to a computer program for running same. The valve (100) comprises a valve housing (10), which comprises a first refrigerant inlet (10a) for connection to the refrigerant circuit downstream of the condenser (3), a second refrigerant inlet (10b) for connection to the refrigerant circuit downstream of the compressor (2), and a refrigerant outlet (10c) for connection to the refrigerant circuit upstream of the evaporator (1), and an adjusting element (12) which, in a first position, connects the first refrigerant inlet (10a) to the refrigerant outlet (10c) and, in a second position, connects the second refrigerant inlet (10b) to the refrigerant outlet (10c).

Description

[0001] VALVE FOR A REFRIGERANT CIRCUIT, VALVE ARRANGEMENT AND HEAT PUMP

[0002] The present invention relates to a valve for a refrigerant circuit, in particular for a refrigerant circuit of a heat pump, a valve assembly, and a heat pump. Furthermore, the invention relates to a method for operating a valve for a refrigerant circuit, a computing unit, and a computer program for implementing the method.

[0003] Modern heat pumps are characterized by their high efficiency and can therefore be used particularly attractively for heating and / or cooling a building from an ecological and economic point of view.

[0004] A heat pump of this type has a refrigerant circuit with an evaporator, a compressor, and a condenser. The evaporator absorbs heat, for example, from the environment, which is then released at a higher temperature in the condenser, for example, to a building's heating circuit. The higher temperature is achieved by compressing the refrigerant in the compressor, so that downstream of the compressor, the refrigerant is present as a so-called hot gas.

[0005] Favored by low outside temperatures below approximately 7 to 10 °C and high humidity, a layer of frost and / or ice can form on the evaporator, which can hinder heat transfer and thus impair the efficiency of the heat pump. The ice layer must then be removed through a defrosting process.

[0006] The defrosting process can be carried out, for example, using an electric heating wire attached to a surface of the evaporator. However, this form of defrosting is not energy-efficient, as electrical current is completely converted into heat.

[0007] A more efficient way to defrost the evaporator is to supply hot gas, which can be used to heat the evaporator from the inside. Heat pumps equipped with a 4-2-way valve can reverse the process, so that the evaporator acts as a condenser and the condenser as an evaporator. This reverses the heat flows, and the evaporator can be defrosted using the hot gas escaping from the compressor.

[0008] However, such 4-2-way valves are only used in heat pumps that are used for both heating and cooling. Simple heat pumps without a cooling function do not have a 4-2-way valve, so they require additional lines and valves to supply the hot gas needed for defrosting to the evaporator.

[0009] DE 10 2005 034 826 B4 shows a heat pump that proposes defrosting an evaporator using hot gas, with the latter being reheated by an electric auxiliary heater. For this purpose, a hot gas line branches off between a compressor and a condenser of the heat pump, which opens upstream of the evaporator inlet. A shut-off valve is installed in the hot gas line, and the electric auxiliary heater is arranged between the hot gas line inlet and the evaporator. If the temperature in the evaporator drops below a predetermined value, the shut-off valve is opened and the auxiliary heater is switched on to defrost the evaporator.

[0010] It is clear that the heat pump proposed in DE 10 2005 034 826 B4 requires several additional components for defrosting the evaporator. The present invention is based on the object of enabling a defrosting process of an evaporator in a refrigerant circuit, in particular in a refrigerant circuit of a heat pump, without, or at least with a reduced number of, additional components.

[0011] This object is achieved by the invention with the features of the independent claims. Advantageous embodiments of the invention are the subject of the dependent claims and the following description.

[0012] According to the invention, a valve for a refrigerant circuit, in particular for a refrigerant circuit of a heat pump, which contains a compressor, a condenser and an evaporator, a valve arrangement and a heat pump are proposed.

[0013] A valve according to the invention comprises a valve housing with a first refrigerant inlet for connection to the refrigerant circuit downstream of the condenser, a second refrigerant inlet for connection to the refrigerant circuit downstream of the compressor, and a refrigerant outlet for connection to the refrigerant circuit upstream of the evaporator. When installed, the first refrigerant inlet on the valve housing is therefore supplied with refrigerant that has already been cooled to a low temperature level by heat transfer in the condenser. The second refrigerant inlet on the valve housing, in contrast, is supplied with hot gas escaping directly from the compressor, which is at a high temperature level. For example, the temperature of the refrigerant downstream of the compressor can be 50°C to 70°C, in particular 60°C.

[0014] The valve additionally includes an adjusting element that connects the first refrigerant inlet to the refrigerant outlet in a first position and the second refrigerant inlet to the refrigerant outlet in a second position. Thus, when the valve is installed, low-temperature refrigerant flows to the evaporator via the refrigerant outlet when the adjusting element is in the first position, and high-temperature refrigerant flows to the evaporator via the refrigerant outlet when the adjusting element is in the second position.

[0015] The valve can therefore be used both for regular heat pump operation and for defrosting the evaporator in the refrigerant circuit. Regular operation refers to an operating state of the heat pump in which, in accordance with its intended purpose, it absorbs heat via the evaporator and releases it via the condenser to a secondary circuit, e.g., a building's heating circuit.

[0016] In particular, the valve can be operated in such a way that the adjustment element is in the first position during regular operation of the heat pump and in the second position during the evaporator defrosting process. Thus, only a single valve is required to supply refrigerant to the evaporator, and no additional valve is needed for the defrosting process.

[0017] The first position of the adjusting element can in particular be a first adjusting range in which the adjusting element moves in order to operate the evaporator at a suitable temperature level depending on an operating point of the heat pump and to provide a required amount of refrigerant for the evaporator. The second position of the adjusting element can be a fixed position in which a flow cross-section formed by the adjusting element, through which the hot refrigerant flows from the second refrigerant inlet to the refrigerant outlet of the valve, is at a maximum. It is also possible for the second position to also be an adjusting range within which the flow cross-section of the valve can be varied to adjust a required amount of hot refrigerant. In this case, in particular, a second position can be set in such a way that an optimal defrosting temperature is achieved in the evaporator.An optimal defrosting temperature is understood to mean, in particular, a temperature that enables defrosting within a predetermined time.

[0018] According to one embodiment, the valve can comprise a throttle element that serves to adjust a refrigerant flow to the evaporator when the adjusting element is in the first position. In other words, in the first position of the adjusting element, the valve can serve as an expansion valve, through which refrigerant escaping from the condenser can be introduced into the evaporator at a lower pressure level. For this purpose, the adjusting element can be designed such that the second refrigerant inlet is closed when the adjusting element is in the first position, so that no hot refrigerant reaches the evaporator from the compressor during regular operation of the heat pump.

[0019] The throttle element can in particular be a controllable throttle element in the form of a thermostatic or electronically controllable expansion valve, with which the condensed refrigerant can be supplied to the evaporator as required.

[0020] According to one embodiment, the throttle element can be attached to the adjusting element. In particular, the throttle element can be at least partially contained in the adjusting element, or the adjusting element can be at least partially contained in the throttle element.

[0021] According to one embodiment, the adjusting element can be designed such that the first refrigerant inlet is closed when the adjusting element is in the second position. This can prevent refrigerant from the condenser from flowing into the evaporator in addition to the hot gas from the compressor during a defrosting process. In this way, the evaporator can be defrosted particularly quickly and efficiently. According to one embodiment, a filter can be arranged in the first refrigerant inlet and / or in the second refrigerant inlet of the valve housing. This can in particular be a sieve filter which protects the adjusting element from particles and moisture. At least one such filter is usually included as a separate component in a refrigeration circuit. By integrating the filter(s) into the valve housing, these components can be dispensed with and the refrigeration circuit can be designed to be compact.

[0022] According to one embodiment, the adjusting element can be a linear adjusting element with edge control. This can be arranged in a direction perpendicular to the first and second refrigerant inlets and movable in this direction. The adjusting element can perform a linear movement in the direction perpendicular to the first and second refrigerant inlets in order to move from the first position to the second position. In particular, during a linear movement of the adjusting element from the first position to the second position, an edge of the valve element can form an opening in the valve housing or can be aligned with an opening in the valve housing, so that in the second position of the valve element, the second refrigerant inlet is connected to the refrigerant outlet. The edge can, for example, be located at a recess in the adjusting element.In the present case, an edge should also be understood as a circumference of a bore in the adjusting element, which can be at least partially aligned with an opening in the valve housing in order to open the second refrigerant inlet.

[0023] According to one embodiment, the valve can comprise an adjusting device configured to move the adjusting element from the first to the second position. The adjusting device can comprise, for example, an electromagnet and / or an electric motor. The electric motor can, in particular, be a linear motor. In particular, the adjusting device can also be configured to adjust the throttle element. For this purpose, an electrically / electronically controlled adjusting device or a thermostatically controlled adjusting device can be used.

[0024] The valve arrangement according to the invention for a refrigerant circuit, having a compressor, a condenser, and an evaporator, comprises a valve having the features described above and a first refrigerant line connecting an outlet of the condenser to a first refrigerant inlet of the valve, a second refrigerant line connecting an outlet of the compressor to a second refrigerant inlet of the valve; and a third refrigerant line connecting a refrigerant outlet of the valve to an inlet of the evaporator.

[0025] The heat pump according to the invention contains a refrigerant circuit with a compressor, a condenser, an evaporator and a valve arrangement with the features described above.

[0026] Furthermore, a method for operating a valve for a refrigerant circuit having the features described above, a computing unit, and a computer program for implementing the method are proposed. The refrigerant circuit contains a compressor, a condenser, and an evaporator and is incorporated in particular in a heat pump.

[0027] In the method according to the invention, a first position of an adjusting element in the valve is first set, whereby a refrigerant flow from the compressor through the condenser is supplied to the evaporator via a first refrigerant inlet and a refrigerant outlet of the valve. In particular, the valve can be operated as an expansion valve in the first position of the adjusting element. The first position of the adjusting element can in particular be a first adjustment range in which the adjusting element moves in order to operate the evaporator at a suitable temperature level depending on an operating point of the heat pump and thereby provide a required amount of refrigerant when the heat pump is in regular operation.

[0028] This determines the value of a state variable of the evaporator, which can be used to determine whether the evaporator is iced up and a defrosting process needs to be initiated. For example, the state variable can be the ambient temperature of the evaporator, which can be measured with a temperature element. Alternatively or additionally, the temperature of the refrigerant at the evaporator inlet can be measured with another temperature element. In particular, a defrosting process can be initiated depending on the ambient temperature and the temperature of the refrigerant at the evaporator inlet.

[0029] The value of the state variable can be determined continuously or at predetermined intervals. In particular, the value of the state variable can be determined under predetermined boundary conditions, e.g., at a constant operating point of the heat pump. For this purpose, the compressor speed can also be taken into account.

[0030] If the determined value of the evaporator's state variable lies within a predetermined value range, the first position of the adjustment element is maintained. In particular, the heat pump can continue to operate normally in this case, and no defrosting process is required. When using the ambient temperature as the state variable, the predetermined range can be, for example, above 5°C to 8°C. In particular, predetermined values ​​of the refrigerant temperature at the evaporator inlet and the ambient temperature can be stored in a characteristic map depending on the compressor speed, and this characteristic map can be used to determine whether a defrosting process is necessary.If the value of the state variable(s) of the evaporator lies outside the predetermined value range, a second position of the adjusting element in the valve is set, whereby at least a portion of the refrigerant flow from the compressor is supplied to the evaporator via a second refrigerant inlet of the valve. In particular, the valve can be switched from the first position to the second position when it is determined that the value of the state variable leaves the predetermined range.

[0031] A computing unit according to the invention comprises a processor configured to execute a method having the features described above. The computing unit can, in particular, be a heat pump controller. A method according to the invention is also embodied as a computer program with program code for carrying out all method steps, so that it can be implemented, for example, in an existing heat pump controller.

[0032] BRIEF DESCRIPTION OF THE CHARACTERS

[0033] Figure la shows schematically a refrigerant circuit of a heat pump not according to the invention; and

[0034] Figure 1b shows schematically a refrigerant circuit of a heat pump according to an embodiment of the invention.

[0035] Figures 2a and 2b schematically show a valve for a refrigerant circuit according to an embodiment of the invention in a cross-sectional view.

[0036] Figures 3a and 3b schematically show a valve for a refrigerant circuit according to a further embodiment of the invention in a cross-sectional view.

[0037] Figures 4a and 4b schematically show two different cross-sectional views of a valve for a refrigerant circuit according to yet another embodiment of the invention, wherein an adjusting element of the valve is in a first position.

[0038] Figures 5a and 5b schematically show the valve shown in Figures 4a and 4b, wherein the adjusting element of the valve is in a second position.

[0039] Detailed description of preferred embodiments

[0040] In the following, exemplary embodiments of the present invention are described in detail using exemplary figures. The features of the exemplary embodiments can be combined in whole or in part, and the present invention is not limited to the described exemplary embodiments. In the figures, identical elements are provided with identical reference numerals, so that a repeated description of the elements is omitted unless necessary.

[0041] Figure 1a schematically shows a refrigerant circuit of a heat pump not according to the invention. The refrigerant circuit contains a compressor 2, which is driven by a motor 2a, e.g., an electric motor 2a, a condenser 3, a refrigerant receiver 4, an expansion valve 5, an evaporator 1, and a bypass valve 6, which is arranged between the compressor 2 and the evaporator 1. The individual components of the refrigerant circuit are connected by refrigerant lines (not further designated), which are indicated by arrows that mark a flow direction.

[0042] A filter 5a, 6a is installed upstream of the expansion valve 5 and the bypass valve 6, protecting them from any particles and moisture. Furthermore, a first pressure and temperature sensor pT1 and a second pressure and temperature sensor pT2, as well as a safety high-pressure switch pSH, are installed upstream of the compressor 2, and a second pressure and temperature sensor pT2 and a safety high-pressure switch pSH are installed downstream of the compressor. The first pressure and temperature sensor pT1 is signal-connected to the expansion valve 5, and the safety high-pressure switch pSH is signal-connected to the compressor motor 2a (indicated by the thin dashed lines between these elements). During normal operation of the heat pump, gaseous refrigerant, which has absorbed heat in the evaporator 1, e.g., from the environment, flows from the evaporator 1 to the compressor 2. There, the refrigerant is compressed and flows as hot gas from the compressor 2 into the condenser 3.

[0043] The temperature and pressure of the hot gas flowing from compressor 2 can be measured using the second pressure and temperature sensor pT2. If the pressure downstream of compressor 2 rises to an unacceptably high level, compressor motor 2a can be shut down using the safety high-pressure switch pSH.

[0044] In the condenser 3, the refrigerant can be liquefied, releasing the heat absorbed in the evaporator 1, for example, to a building's heating circuit (see arrows VL, RL, which indicate a flow and return line, e.g., of a heating circuit). The condensed refrigerant then flows from the condenser into the refrigerant receiver 4 and from there via the filter 5a to the expansion valve 5.

[0045] By means of the expansion valve 5, the refrigerant can be expanded to an initial pressure, allowing it to return to a gaseous state in the evaporator 1 and absorb heat in the process. To operate the evaporator at a suitable temperature level at every operating point of the heat pump and to supply a suitable amount of refrigerant, the expansion valve 5 can receive a signal from the pressure and temperature sensor pTl and adjust the amount of refrigerant to be introduced into the evaporator according to the measured pressure and temperature upstream of the compressor 2.

[0046] The bypass valve 6 with the upstream filter 6a is arranged between an outlet of the compressor 2 and an inlet of the evaporator 1. This can be used to direct hot gas from the compressor 2 directly into the evaporator 1 in the event of icing on the evaporator, thus defrosting it. Icing can be detected, for example, by the temperature of the refrigerant at the inlet of the evaporator, which can be measured with a temperature sensor at this point (not shown). In particular, an additional ambient temperature can be measured with an additional temperature sensor (not shown), and the presence of icing can be determined based on both temperature values. The speed of the compressor 2 can also be taken into account.

[0047] Figure 1b schematically shows a refrigerant circuit of a heat pump according to an embodiment of the invention, which differs from the refrigerant circuit shown in Figure 1a in that it comprises a valve 100 that performs all the functions of the components 5, 5a, 6, 6a outlined in dashed lines in Figure 1a. In other words, the valve 100 is configured to serve both as an expansion valve and as a bypass valve. Furthermore, the valve comprises integrated filters that eliminate the need for separate filters in the refrigerant lines.

[0048] The valve 100 comprises a valve housing 10 with two refrigerant inlets 10a, b and one refrigerant outlet 10c. A first refrigerant inlet 10a is connected to an outlet of the collector 4 via a first refrigerant line 100aa downstream of the condenser 3. A second refrigerant inlet of the valve 100 is connected to the refrigerant circuit via a second refrigerant line 100ab downstream of the compressor 2, and the refrigerant outlet 10c of the valve 100 is connected to the refrigerant circuit via a third refrigerant line 100ac upstream of the evaporator.

[0049] Detailed exemplary embodiments of the valve 100 according to the invention are shown in Figures 2a to 5b and are explained in more detail in conjunction with these figures. In a first operating mode of the heat pump, in which it is in regular operation, the valve 100 functions as an expansion valve, and condensed refrigerant from the collector 4 reaches the evaporator 1 via the first refrigerant inlet 10a and the refrigerant outlet 10c. The valve 100 is connected to the pressure and temperature sensor pTl in a similar way to the expansion valve 5 in Figure 1a and is thus configured to operate the evaporator at a suitable temperature level at each operating point of the heat pump and to adjust the amount of refrigerant to be evaporated according to the pressure and temperature upstream of the compressor 2.

[0050] During the first operating mode, a value of a state variable of the evaporator 1 is also recorded. In particular, this can be a temperature of the refrigerant at the inlet of the evaporator 1 and / or the ambient temperature. If the measured temperatures fall below a predetermined value, the valve 100 is operated in a second operating mode, in which hot gas from the outlet of the compressor 2 can reach the evaporator 1 via the second refrigerant inlet 10b and the refrigerant outlet 10c of the valve 100. For this purpose, predetermined values ​​for the temperature of the refrigerant at the inlet of the compressor and the ambient temperature can be set depending on a speed of the compressor and stored in a characteristic map.

[0051] In this way, the valve 100 combines the functions of the expansion valve 5 and the bypass valve 6 according to Figure 1, thereby significantly reducing the required component count, since the filters 5a, 6a upstream of the expansion and bypass valves 5, 6 can also be replaced by internal filters. Furthermore, the refrigerant circuit's piping can be designed much more compactly by using only one valve 100.

[0052] Figures 2a and 2b schematically show a cross-sectional view of a valve 100 for a refrigerant circuit according to an embodiment of the invention, which can be used in the refrigerant circuit shown in Figure 1b. The illustrated valve 100 has a valve housing 10 with a first refrigerant inlet 10a, a second refrigerant inlet 10b, and a refrigerant outlet 10c. The two refrigerant inlets 10a, 10b are arranged opposite one another on a circumference of the valve housing 10 and from there each extend radially inward beyond a central axis of the valve housing 10. The refrigerant outlet 10c is attached to an end face of the valve housing perpendicular to the first and second refrigerant inlets and extends axially along the central axis.The first refrigerant inlet 10a can be connected to a refrigerant circuit downstream of a condenser 3, in particular at the outlet of the condenser 3 or at the outlet of a refrigerant collector 4. The second refrigerant inlet 10b can be connected to the refrigerant circuit downstream of a compressor 2, in particular at the outlet of the compressor 2, and the refrigerant outlet 10c can be connected to the refrigerant circuit upstream of an evaporator, in particular at an inlet of the evaporator 1.

[0053] A filter 11a, 11b is mounted in each of the first and second refrigerant inlets 10a, 10b of the present valve 100, and a cylindrical adjusting element 12 is arranged along the center axis of the valve housing 100 as a linear adjusting element 12, which is linearly guided in a first and a second guide bore 10g1, 10g2.

[0054] The first guide bore 10g1 is located above the second refrigerant inlet 10b, and the second guide bore is located between the first and second refrigerant inlets 10a, 10b. The adjusting element 12 has a valve needle 12d at its lower end, which forms a throttle element with a corresponding valve seat 10d in the valve housing 10. In addition, the adjusting element 12 contains a recess 12a as an edge control 12a, which interacts with the second guide bore 10g2, which is arranged between the first and second refrigerant inlets 10a, 10b. In Figure 2a, the adjusting element 12 of the valve 100 is in a first position, in which the valve 100 can be operated as an expansion valve. The first position is, in particular, a first adjustment range of the adjusting element 12 for controlling the amount of refrigerant to be introduced into the evaporator, which, for example,can be determined by a maximum amount of refrigerant to be introduced into the evaporator.

[0055] In this position, cooled refrigerant previously liquefied in the condenser 3 can flow into the valve housing 10 via the first refrigerant inlet 10a and the filter 11a. To supply the refrigerant to the evaporator 1, the valve needle 12d of the adjusting element 12 can be raised from the valve seat 10d according to the required amount of refrigerant to be evaporated and can release a valve gap 10d, 12d through which the refrigerant can flow to the refrigerant outlet 10c of the valve 10 (indicated by the arrows at the first refrigerant inlet 10a and at the refrigerant outlet 10c).

[0056] The narrow valve gap 10d, 12d leads to a strong throttling of the refrigerant flow, whereby the refrigerant can enter the evaporator 1 at a low pressure and evaporate therein.

[0057] The valve needle 12d can be lifted from the valve seat 10d by means of an adjusting device (not shown), for example, an electromagnet or an electric motor, and can be moved back into the valve seat 10d, for example, by switching off the electromagnet. Instead of an electrically / electronically controlled adjusting device, a thermostatically controlled adjusting device can also be used.

[0058] The cross-section of the valve gap 10d, 12d can be adjusted according to the required amount of refrigerant (indicated by the black double arrow on the adjusting element 12). In particular, the stroke of the valve needle 12d (first adjustment range) is limited such that the recess 12a of the adjusting element 12 does not enter the second guide bore 10g2, but remains in a region of the first refrigerant inlet 10a. In this way, the second refrigerant inlet 10b of the valve housing 10 remains closed, and no hot gas can flow from the compressor to the evaporator 1.

[0059] In Figure 2b, the adjusting element 12 is in a second position in which the valve needle 10d is completely separated from the valve seat 10d and the recess 12a is located in the region of the second guide bore 10g2.

[0060] In this way, the flow path from the second refrigerant inlet 10b to the refrigerant outlet 10c is now open, and hot gas can flow from the compressor to the evaporator (indicated by the arrows from the second refrigerant inlet 10b to the refrigerant outlet 10c). Since, in the second position of the adjusting element 12, the hot gas at the second refrigerant inlet 10b has a higher pressure than any refrigerant present at the first refrigerant inlet 10a, the latter does not reach the refrigerant outlet 10c, or at least only in small quantities. The second position of the adjusting element 12 can also be adjusted by means of an adjusting device, e.g., an electromagnet or electric motor. In particular, the same adjusting device can be used that is used to adjust the valve stroke in the first position of the adjusting element.The illustrated valve 100 thus uses a single adjusting element 12 both for metering refrigerant into the evaporator 1 during regular operation of the heat pump and for opening a bypass line from the compressor 2 to the evaporator 1 when defrosting is necessary. In particular, the size of the gap 10g2 can be varied such that an optimal temperature for defrosting is set in the evaporator 1. An optimal temperature for defrosting the evaporator is to be understood in particular as a temperature that enables defrosting within a predetermined time. Figures 3a and 3b schematically show a cross-sectional view of a valve 100a for a refrigerant circuit according to a further exemplary embodiment of the invention, which can also be used in the refrigerant circuit shown in Figure 1b.

[0061] The valve 100a shown here differs from the valve 100 shown in Figures 2a and 2b by a design of the adjusting element 12, which in this case is designed as a two-part linear actuator. An upper part 12-1 of the adjusting element 12 contains the valve needle 12d, and the associated valve seat 10d is mounted in a lower part 12-2 of the adjusting element 12, which has a cylindrical shape with a larger diameter than the upper part 12-1. The upper part 12-1 of the adjusting element 12 is linearly guided in a first guide bore 10g1, which is arranged perpendicular to the first refrigerant inlet, and the lower part 12-2 is linearly guided in a second, larger guide bore 10g2, which is arranged perpendicular to the second refrigerant inlet 10b.

[0062] The lower part 12-2 of the adjusting element 12 also contains a vertically extending first bore 12a2, which extends from the valve seat 10d to an opposite end face of the lower part 12-2, as well as a second bore 12a1 running perpendicular to the first bore 12a2 and extending from the first bore to an outer periphery of the second part 12-2. A spring 12b is arranged below the second part 12-2 of the adjusting element 12, the spring force of which holds the adjusting element 12 in the first position.

[0063] In this first position, shown in Figure 3a, the lower part 12-2 of the adjusting element 12 is pressed against an opposite surface of the housing 10 by spring force, and the second bore 12a1 is closed to the outside by the second guide bore 10g2. Consequently, the valve 100a can be operated as an expansion valve analogous to the valve 100 shown in Figure 2a (indicated by the arrows at the first refrigerant inlet 10a and the refrigerant outlet 10c).

[0064] For this purpose, the valve needle 12d attached to the upper part 12-1 of the adjusting element 12 can be raised from the valve seat 10d in the lower part 12-2 of the adjusting element 12 by means of an adjusting device, e.g., an electromagnet or electric motor, according to the desired temperature level of the refrigerant in the evaporator 1 and the amount of refrigerant to be evaporated, so that a valve gap 10d, 12d is formed, through which the refrigerant can reach the refrigerant outlet 12b via the first bore 12a2 (indicated by the black double arrow on the upper part 12-1 of the adjusting element 12). In contrast to the valve 100 shown in Figure 2a, the position of the lower part 12-2 of the adjusting element can thus remain constant in the first position, and only the upper part 12-1 can move within a predetermined adjustment range to meter the refrigerant to be introduced into the evaporator. The adjustment range can be e.g.be determined by a maximum amount of refrigerant to be introduced into the evaporator.

[0065] In Figure 3b, the adjusting element 12 is in the second position, in which the lower part 12-2 is pressed downward by a force acting against the spring 12b, so that the second bore 12a1 is arranged in front of the second refrigerant inlet 10b. The required force can also be applied by an adjusting device, e.g., an electromagnet or an electric motor. In particular, this can be the same adjusting device that is used to actuate the valve needle. However, it is also possible for different adjusting devices to be attached to or connected to the valve 100a.

[0066] In the second position of the adjusting element 12, the valve needle 12d can close the first bore 12a2, so that regardless of the pressure at the first and second refrigerant inlets, no condensed refrigerant reaches the refrigerant outlet 10c via the first refrigerant inlet 10a. Instead, hot gas can flow from the compressor 2 via the second refrigerant inlet 10b to the refrigerant outlet 10c and from there into the evaporator 1 (indicated by the arrows at the second refrigerant inlet 10b and the refrigerant outlet 10c). Since the second refrigerant inlet 10b is located downstream of the valve seat 10d, a filter can be omitted at this point in the present embodiment of the valve 100a. However, it is equally possible for a filter 11 to be installed in the second refrigerant inlet 10b.

[0067] Figures 4a and 4b each schematically show a cross-sectional view of a valve 100b for a refrigerant circuit according to a further embodiment of the invention, which can be used in the refrigerant circuit in Figure 1. Figure 4a shows the same cross-sectional view as Figures 2a to 3b, while Figure 4b shows a cross-sectional view of the valve 100b rotated by 90 degrees relative to the latter. In Figures 4a and 4b, the valve 100b or its adjusting element 12 is in the first position, in which the valve 100b can be operated as an expansion valve.

[0068] In the embodiment shown here, the first and second refrigerant inlets 10a, 10b are located on one side of the valve housing 10, and the refrigerant outlet 10c is located on a side opposite the refrigerant inlets 10a, 10b. The first refrigerant inlet 10a extends radially inward from an outer circumference of the valve housing, transitioning from a cylindrical shape to a conical shape. A filter 11a is arranged in the cylindrical section of the first refrigerant inlet 10a. The refrigerant outlet 10c is arranged directly opposite the first refrigerant inlet 10a and essentially mirrors its geometry, with an opening for connecting the second refrigerant inlet 10b being arranged in the conical section of the refrigerant outlet 10c.The tips of the two conical sections of the first refrigerant inlet 10a and the refrigerant outlet 10c are connected via a thin bore 10e in the valve housing 10, which can be opened and closed by means of the adjusting element 12.

[0069] The second refrigerant inlet 10b is located below the first refrigerant inlet 10a in the valve housing and extends radially inward from the outer circumference of the valve housing, essentially parallel to the first refrigerant inlet. The second refrigerant inlet is designed as a cylindrical bore in which a filter 11b is also arranged. To connect the second refrigerant inlet 10b to the refrigerant outlet 10c, a bore 10f branches off from the latter, which opens into the conical section of the refrigerant outlet 10c. This bore can be opened and closed by means of the adjusting element 12.

[0070] In the present case, the adjusting element 12 is designed as a plate-shaped linear actuator 12, which has a rod-shaped section 12-3 for connecting an adjusting device and a plate-shaped section 12-4 with a drop-shaped opening 12a as the control edge 12a. It is arranged between the refrigerant inlets 10a, 10b and the refrigerant outlet 10c in a guide 10g along a central axis of the valve housing 10. By a linear movement of the adjusting element 12, either the first or the second refrigerant inlet 10a, 10b can be connected to the refrigerant outlet 10c.

[0071] When the adjusting element 12 of the valve 100b is in the first position, as shown here, a lower section of the plate-shaped section 12-4 closes the bore 10f, which connects the second refrigerant inlet 10b to the refrigerant outlet 10c, and the drop-shaped bore 12a overlaps with the bore 10e in the valve housing 10, which connects the first refrigerant inlet 10a to the refrigerant outlet 10c (indicated by the thin arrows labeled "open" and "closed"). In this way, condensed refrigerant can flow from the condenser through the valve 100b to the evaporator 1 (indicated by the thick arrows at the first refrigerant inlet 10a and the refrigerant outlet 10c).

[0072] The overlap of the drop-shaped opening 12a with the bore 10e can be adjusted according to the required amount of refrigerant to be evaporated (indicated by the black double arrow on the adjusting element 12). The precise metering of the refrigerant quantity is achieved by the arrangement of the opening 12a in the adjusting element 12 relative to the bore 10e. Figure 4b clearly shows that, when fully opened, the bore 10e is located in the upper region of the opening 12a, where it forms its drop shape. By a linear downward movement of the adjusting element 12, the cross-section of the bore 10e can be continuously reduced, thus precisely adjusting the amount of refrigerant to be evaporated.

[0073] Analogous to the valves 100, 100a shown in Figures 2a to 3b, the adjusting element 12 can be actuated as an adjusting device via the rod-shaped section 12-3, e.g., by means of an electromagnet or electric motor (not shown). In the present case, this means that the adjusting element 12 can be moved up and down in the guide 10g in order to set a required opening cross-section of the bore 10g for the desired temperature of the refrigerant in the evaporator 1 and the amount of refrigerant to be evaporated. Instead of an electrically / electronically controlled adjusting device, a thermostatically controlled adjusting device can also be used.

[0074] Figures 5a and 5b schematically show the valve 100b shown in Figures 4a and 4b in the second position of the adjusting element 12, in which the valve 100b is operated as a bypass valve.

[0075] In this second position, the plate-shaped section 12-4 of the adjusting element 12 rests with one end face against a lower stop of the guide 10g, and a section arranged above the drop-shaped opening 12 closes the bore 10e between the first refrigerant inlet 10a and the refrigerant outlet 10c. Instead, the drop-shaped opening 12a now overlaps with a cross-section of the bore 10f, which connects the second refrigerant inlet 10b with the refrigerant outlet 10c (indicated by the thin arrows labeled "open" / "closed"). Here, too, the size of the cross-section of the bore 10f can be varied such that an optimal defrosting temperature is established in the evaporator 1.

[0076] Adjustment of the adjusting element 12 from the first to the second position can also be effected via a suitable adjusting device, such as an electromagnet or an electric motor. In particular, the same adjusting device can be used for this purpose which, in the first position of the adjusting element 12, adjusts the opening cross-section of the bore 10e for metering the refrigerant to be evaporated.

Claims

PATENT CLAIMS 1. Valve (100) for a refrigerant circuit, in particular for a refrigerant circuit of a heat pump, which contains a compressor (2), a condenser (3) and an evaporator (1), the valve (100) comprising a valve housing (10) with a first refrigerant inlet (10a) for connection to the refrigerant circuit downstream of the condenser (3) and a second refrigerant inlet (10b) for connection to the refrigerant circuit downstream of the compressor (2) as well as a refrigerant outlet (10c) for connection to the refrigerant circuit upstream of the evaporator (1), and an adjusting element (12) which, in a first position, connects the first refrigerant inlet (10a) to the refrigerant outlet (10c) and, in a second position, connects the second refrigerant inlet (10b) to the refrigerant outlet (10c).

2. Valve (100) according to claim 1, further comprising a throttle element (12d) for adjusting a refrigerant flow to the evaporator (1) when the adjusting element (12) is in the first position.

3. Valve (100) according to claim 2, wherein the throttle element (12d) is attached to the adjusting element (12).

4. Valve (100) according to one of the preceding claims, wherein the adjusting element (12) is designed such that the second refrigerant inlet (10b) is closed when the adjusting element (12) is in the first position.

5. Valve (100) according to one of the preceding claims, wherein the adjusting element (12) is designed such that the first refrigerant inlet (10a) is closed when the adjusting element (12) is in the second position.

6. Valve (100) according to at least one of the preceding claims, wherein a filter is arranged in the first refrigerant inlet (10a) and / or in the second refrigerant inlet (10b).

7. Valve (100) according to at least one of the preceding claims, wherein the adjusting element (12) is a linear adjusting element with edge control.

8. Valve (100) according to at least one of the preceding claims, wherein the adjusting element is arranged in a direction perpendicular to the first and second refrigerant inlets (10a, 10b) and is movable in this direction.

9. Valve (100) according to at least one of the preceding claims, further comprising an adjusting device which is configured to move the adjusting element (12) from the first to the second position.

10. Valve (100) according to claim 9, wherein the adjusting device is further configured to adjust the throttle element (12d, 12a).

11. Valve arrangement for a refrigerant circuit, in particular for a refrigerant circuit of a heat pump, which contains a compressor (2), a condenser (3) and an evaporator (1), the valve arrangement comprising the valve (100) according to one of the preceding claims; a first refrigerant line (100aa) which connects an outlet of the condenser (3) to a first refrigerant inlet (10a) of the valve (100); a second refrigerant line (100ab) which connects an outlet of the compressor (2) to a second refrigerant inlet (10b) of the valve (100); and a third refrigerant line (100ac) which connects a refrigerant outlet (10c) of the valve (100) to an inlet of the evaporator (1).

12. Heat pump with a refrigerant circuit containing a compressor (2), a condenser (3), an evaporator (1) and a valve arrangement according to claim 11.

13. A method for operating a valve (100) for a refrigerant circuit according to at least one of claims 1 to 10, wherein the refrigerant circuit contains a compressor (2), a condenser (3) and an evaporator (1), the method comprising the steps: - setting a first position of an adjusting element (12) in the valve (100), whereby a refrigerant flow from the compressor (2) through the condenser (3) is supplied to the evaporator (1) via a first refrigerant inlet (10a) of the valve (100); - determining a value of a state variable of the evaporator (1); - maintaining the first position of the adjusting element (12) when the value of the state variable of the evaporator (1) is within a predetermined value range; and - Setting a second position of the adjusting element (12) in the valve (100), whereby at least part of the refrigerant flow from the compressor (2) is supplied to the evaporator (1) via a second refrigerant inlet (10b) of the valve (100) when the value of the state variable of the evaporator (1) lies outside the predetermined value range.

14. A computing unit comprising a processor configured to carry out the method according to claim 13.

15. A computer program comprising instructions which, when executed by a computer, cause the computer to carry out the method according to claim 13.

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