Heat pump and method for operating heat pump

Abstract

A heat pump and a method for operating a heat pump are provided. In the heating mode, the heat pump comprises a cooling cycle, and the cooling cycle comprises a compressor, a first heat exchanger, a third heat exchanger, a second expansion valve and a second heat exchanger which are sequentially connected into a loop through fluid pipelines. The cooling cycle further includes an internal heat exchanger having a first conduit and a second conduit in heat exchange contact, where the first conduit is a fluid line portion between the third heat exchanger and the second expansion valve and the second conduit is a fluid line portion between the second heat exchanger and the compressor, wherein the third heat exchanger is configured to reduce a temperature of refrigerant delivered from the first heat exchanger to the internal heat exchanger by releasing heat to a physical medium.

Description

Background Art

[0001] In many cases, heat pump compressors must ensure complete refrigerant vaporization at the compressor input to improve the heat pump's lifespan and efficiency. Suction gas superheat prevents liquid refrigerant from flowing through the compressor. However, controlling suction gas superheat to a specific threshold is crucial to optimize the performance envelope of the compressor in the high compression ratio region.

[0002] US2022 / 136741A1 discloses an air conditioner and its refrigerant flow during heating operation. The refrigerant circulates in the order of a compressor, a four-way valve, a second heat exchanger, a second expansion valve, an internal fourth heat exchanger, an internal third heat exchanger, a first expansion valve, a first heat exchanger, and the four-way valve. During heating operation, the second heat exchanger functions as a condenser and the first heat exchanger functions as an evaporator.

[0003] JP5288020B1 discloses an air conditioner equipped with a four-stage compressor, first through fourth heat exchangers, an indoor heat exchanger, a switching mechanism, an expansion mechanism, and a refrigerant pipe assembly. The first through third heat exchangers act as radiators to cool the compressed refrigerant at an intermediate pressure during cooling operation and as evaporators during heating operation. The fourth heat exchanger acts as a cooler during cooling operation and as an evaporator during heating operation. During heating operation, the refrigerant pipe assembly sequentially flows through the first through third heat exchangers.

[0004] WO2020 / 063678A1 discloses an air conditioning system and a control method thereof. The system comprises a compressor, a first heat exchanger, a second heat exchanger, an intermediate heat exchanger, a first branch, and a first throttling element disposed at the inlet of the second heat exchanger. The intermediate heat exchanger comprises a first heat exchange section and a second heat exchange section, each of which is capable of exchanging heat.

[0005] EP1886076A0 discloses a heat pump system comprising a compressor, a reversing valve, an outdoor heat exchanger, an indoor heat exchanger (coupled via refrigerant piping in a conventional refrigeration circuit), and a refrigerant-water heat exchanger. In air cooling-water heating mode, air heating-water heating mode, and water heating only mode, water from a water tank (such as a storage tank or swimming pool) flows through the heat exchanger to exchange heat with piping flowing through the refrigerant. A reservoir may be provided for refrigerant charge control. A pipeline connects the reservoir to the circuit between the outdoor and indoor heat exchangers to introduce liquid refrigerant, and a pipeline connects the circuit upstream of the suction port to the compressor to return refrigerant to the reservoir. A controller controls the flow of refrigerant into and out of the reservoir by selectively opening and closing control valves in the pipelines. First and second expansion valves are installed in a section of the refrigerant piping. The first expansion valve is associated with the outdoor heat exchanger, and the second expansion valve is associated with the indoor heat exchanger. Each expansion valve is equipped with a bypass line equipped with a check valve, allowing flow in only one direction. The check valve in the bypass line associated with the outdoor heat exchanger expansion valve transfers refrigerant from the outdoor heat exchanger to the indoor heat exchanger, thereby bypassing the outdoor heat exchanger expansion valve and delivering refrigerant to the indoor heat exchanger expansion valve. The check valve in the bypass line associated with the indoor heat exchanger expansion valve transfers refrigerant from the indoor heat exchanger to the outdoor heat exchanger, thereby bypassing the indoor heat exchanger expansion valve and delivering refrigerant to the outdoor heat exchanger expansion valve. Furthermore, a refrigerant-to-water heat exchanger is connected to the refrigerant lines, exchanging heat between the refrigerant flowing through the refrigerant lines and the water flowing through the water circulation lines.

[0006] In view of the above, the object of the present invention is to provide a heat pump and a method for operating a heat pump which is cost-effective, efficient and reliable, especially in heating mode. Summary of the Invention

[0007] In order to solve the above problems, a heat pump and a method for operating a heat pump are provided, which have the features of the independent claims. The dependent claims relate to embodiments thereof. Various aspects and embodiments of the present invention will be described below.

[0008] A first aspect relates to a heat pump including a cooling cycle. In heating mode, the cooling cycle includes: a compressor, a first heat exchanger, a third heat exchanger, a second expansion valve, and a second heat exchanger, which are sequentially connected in a loop via a fluid pipeline. In heating mode, the cooling cycle also includes an internal heat exchanger having a first conduit and a second conduit. The first conduit is in heat exchange contact with the second conduit, wherein the first conduit is the portion of the fluid pipeline between the third heat exchanger and the second expansion valve, and the second conduit is the portion of the fluid pipeline between the second heat exchanger and the compressor.

[0009] In heating mode, the compressor is configured to compress the refrigerant in the cooling cycle. The first heat exchanger is a condenser and is configured to add heat energy from the refrigerant to the fluid circuit to be heated. The third heat exchanger is configured to reduce the temperature of the refrigerant delivered from the first heat exchanger to the internal heat exchanger by releasing heat to the second physical medium. The second expansion valve is configured to reduce the pressure of the refrigerant after it passes through the expansion valve. The second heat exchanger is an evaporator, evaporating the refrigerant by adding heat energy from the first physical medium. This has the advantage of reducing suction superheat in heating mode, thereby optimizing the operating range of the compressor and improving the performance range of the compressor envelope parameters in the high compression ratio region in heating mode.

[0010] In some embodiments, the cooling cycle may include, in cooling mode, a compressor, a second heat exchanger, a first expansion valve, and the first heat exchanger, sequentially connected to form a loop via a fluid pipeline. The cooling cycle may also include, in cooling mode, an internal heat exchanger, wherein a first conduit of the internal heat exchanger is a portion of the fluid pipeline between the second heat exchanger and the first expansion valve, and a second conduit of the internal heat exchanger is a portion of the fluid pipeline between the first heat exchanger and the compressor.

[0011] The compressor can be configured to compress refrigerant in a cooling cycle, and the first heat exchanger can be an evaporator configured to add thermal energy from the fluid circuit to the refrigerant. The first expansion valve can be configured to reduce the pressure of the refrigerant after the refrigerant passes through the expansion valve. The second heat exchanger can be a condenser, condensing the refrigerant by releasing the refrigerant's thermal energy to a third physical medium. This has the advantage of reducing suction superheat in cooling mode, thereby optimizing the operating range of the compressor and thereby increasing the performance range of the compressor envelope parameters in the high compression ratio region in cooling mode.

[0012] In some embodiments, the heat pump can be configured to switch between a heating mode and a cooling mode, and the cooling cycle can include a four-way valve, a first one-way valve, and a second one-way valve for switching between the heating and cooling modes. The four-way valve can be configured to: in heating mode, connect the fluid line from the compressor outlet to the first heat exchanger and the fluid line from the second heat exchanger to the second conduit of the internal heat exchanger; in cooling mode, connect the fluid line from the compressor outlet to the second heat exchanger and the fluid line from the first heat exchanger to the second conduit of the internal heat exchanger. The first expansion valve can be bypassed in the direction from the first heat exchanger to the first conduit of the internal heat exchanger by a fluid line including a third heat exchanger and the first one-way valve, and the second expansion valve can be bypassed in the direction from the second heat exchanger to the first conduit of the internal heat exchanger by a fluid line including the second one-way valve.

[0013] Thus, a heat pump is provided that can operate efficiently in both heating mode and cooling mode.

[0014] In some embodiments, the first conduit of the internal heat exchanger is bypassed by a fluid line including a bypass valve (particularly a controllable valve). This has the technical effect of controlling the suction gas superheat in cooling mode, ensuring that the refrigerant temperature supplied to the compressor is above a predetermined temperature. This improves the performance range of the compressor envelope parameters in the high compression region, ultimately increasing the overall efficiency of the heat pump.

[0015] In a particularly advantageous embodiment, the heat pump can be configured to control the bypass valve so that the temperature of the refrigerant delivered to the compressor input in cooling mode is lower than a first preset temperature; and / or so that the temperature of the refrigerant delivered to the compressor input in cooling mode is higher than a second preset temperature. This has the advantage that, because the refrigerant supplied to the compressor has an optimal temperature, the operation of the compressor can be optimized at a lower cost.

[0016] In a highly controllable embodiment, the cooling cycle can further include a three-way valve and a bypass of the third heat exchanger in heating mode. The heat pump can be configured to control the flow through the third heat exchanger and the bypass of the third heat exchanger via the three-way valve so that the refrigerant temperature delivered to the compressor input in heating mode is lower than a third preset temperature; and / or the refrigerant temperature delivered to the compressor input in heating mode is higher than a fourth preset temperature. This has the advantage of improving the overall efficiency of the heat pump (particularly the compressor) because the refrigerant temperature delivered to the compressor is within a preferred temperature range, allowing the compressor to operate at a preferred operating point with high efficiency and a wide performance range.

[0017] In some embodiments, the three-way valve can be implemented by one or more (particularly two or more) three-way valve assemblies.

[0018] The first preset temperature may be the same as or different from the third preset temperature. The second preset temperature may be the same as or different from the fourth preset temperature. The first, second, third, and / or fourth preset temperatures may be preset based on an operating point, an operating mode, an operating range, physical properties of the refrigerant within the cooling cycle, and / or the efficiency of the compressor relative to the temperature of the refrigerant delivered to the compressor. The operating mode, operating point, and / or operating range of the compressor may be provided based on the efficiency of the compressor when compared to other operating points, operating ranges, and / or operating modes.

[0019] In one particularly suitable embodiment, one or more of the following group may be preset constant values: a first preset temperature, a second preset temperature, a third preset temperature, and a fourth preset temperature. Furthermore, in some embodiments, one or more of the following group may be determined based on a temperature difference across the internal heat exchanger: the first preset temperature, the second preset temperature, the third preset temperature, and the fourth preset temperature. The temperature difference across the internal heat exchanger may include at least one of the following group: a temperature difference between the input end of the first conduit and the output end of the second conduit, a temperature difference between the input end of the first conduit and the output end of the first conduit, and a temperature difference between the input end of the second conduit and the output end of the second conduit.

[0020] In some embodiments, one or more of the following group may be determined based on the measured temperature: a first preset temperature, a second preset temperature, a third preset temperature, a fourth preset temperature. The measured temperature may include at least one of the following group: an input temperature of a first conduit of the internal heat exchanger, an output temperature of the first conduit of the internal heat exchanger, an input temperature of a second conduit of the internal heat exchanger, and an output temperature of the second conduit of the internal heat exchanger.

[0021] This has the advantage that the refrigerant temperature delivered to the compressor can be controlled very efficiently, with low energy consumption and low latency. Another advantage is that the service life of the compressor can be extended.

[0022] The first expansion valve may be an electronic expansion valve and / or a thermal expansion valve. In some embodiments, the second expansion valve may be an electronic expansion valve and / or a thermal expansion valve. This has the advantage of enabling very precise control of the cooling cycle with minimal investment and low cost.

[0023] In some embodiments, the first, second, and / or third physical medium may be one or more of the following: air, water, salt water, and soil. In some embodiments, the first and / or second physical medium may be the same or different. In some embodiments, the first and third physical mediums may be the same or different. In some embodiments, the second and third physical mediums may be the same or different. This has the advantage of enabling highly optimized and flexible use of resources while maintaining low investment.

[0024] Preferably, the heat pump may be one or more of the following groups: an air-to-water heat pump, a ground source heat pump, and a brine-to-water heat pump.

[0025] In a particularly advantageous embodiment, the second heat exchanger may include first finned tubes for exchanging heat between the refrigerant and air and / or water and / or other physical media. The third heat exchanger may include second finned tubes for exchanging heat between the refrigerant and air and / or water and / or other physical media. Finned tubes may have the advantage of enabling efficient heat exchange with fluid media such as air, water, and other fluids.

[0026] In a particularly effective embodiment, at least a portion of the first finned tube can be arranged above at least a portion of the second finned tube when viewed from above. This has the advantage that the heat generated by the third heat exchanger can be used to prevent ice (especially glacier-like ice) from forming inside the first finned tube.

[0027] In some embodiments, the heat pump may include a third finned tube, wherein a first section of the third finned tube includes at least a portion of the second heat exchanger (particularly the entire second heat exchanger), and a second section of the third finned tube includes at least a portion of the third heat exchanger (particularly the entire third heat exchanger). In some embodiments, the first section and the second section of the third finned tube may not intersect; in some embodiments, the two sections may intersect. The use of a third finned tube has the advantage of enabling the second and third heat exchangers to be integrated into a single component at a significantly lower cost.

[0028] In a particularly advantageous embodiment, at least a portion of the first section of the third finned tube can be positioned above at least a portion of the second section of the third finned tube, as seen from above. In some embodiments, at least a portion of the second section of the third finned tube can be positioned on the bottom side of the third finned tube. This can have the technical effect of preventing ice (particularly glacial ice) from forming on the bottom side and / or portions of the second heat exchanger.

[0029] A heat exchanger is a unit that transfers heat from a source medium to a receiving medium, wherein the source medium may be separated by a solid wall to prevent mixing or direct contact with the receiving medium. Some non-limiting examples of heat exchangers are: double-pipe heat exchangers (co-current and / or counter-current), shell and tube heat exchangers, plate heat exchangers, condenser heat exchangers, and boiler heat exchangers.

[0030] A bypass can include one or more fluid lines that provide an alternative path for the refrigerant to bypass the bypassed unit. In some embodiments, the bypass can be one-way, such as by a one-way valve. This means that the bypass only exists in one direction and not the other.

[0031] A second aspect of the present application relates to a method for operating a heat pump as described above. This has the advantage that the performance range, efficiency and durability when operating the heat pump can be improved.

[0032] A third aspect of the present application relates to a method for operating a heat pump. The heat pump includes a cooling cycle, which, in a heating mode, includes: a compressor; an internal heat exchanger configured to transfer heat from a high-pressure section of the cooling cycle of the heat pump to a low-pressure section of the cooling cycle before the refrigerant enters an input of the compressor located in the low-pressure section of the cooling cycle. The cooling cycle also includes, in a heating mode, a third heat exchanger configured to cool the refrigerant before the refrigerant enters the high-pressure section of the internal heat exchanger; a bypass of the third heat exchanger; and a three-way valve configured to control flow to the third heat exchanger and flow bypassed by the third heat exchanger.

[0033] The method comprises the following steps in the heating mode: collecting one or more physical system parameters of the heat pump, the one or more physical system parameters comprising one or more of the following groups: the pressure in the cooling cycle, the temperature in the cooling cycle, and the electric power of the inverter of the heat pump. The method also comprises controlling the three-way valve based on the collected one or more physical system parameters and one or more preset thresholds. The one or more physical system parameters and the one or more preset thresholds may correspond to each other. For example, a collected temperature (physical system parameter) may correspond to a minimum and / or maximum temperature as a preset threshold, and the same correspondence applies to the measured pressure.

[0034] In one or more embodiments, the cooling cycle in cooling mode may include: a compressor; an internal heat exchanger configured to transfer heat from a high-pressure section of the cooling cycle of the heat pump to a low-pressure section of the cooling cycle before the refrigerant enters an input end of the compressor of the low-pressure section of the cooling cycle; and a bypass of the high-pressure section of the internal heat exchanger, the bypass including a bypass valve configured to control the flow of refrigerant through the internal heat exchanger located on the high-pressure section of the cooling cycle of the heat pump and the flow of refrigerant bypassing the high-pressure section of the internal heat exchanger. The method in cooling mode may include the following steps: collecting one or more physical system parameters of the heat pump, the one or more physical system parameters including one or more of the following group: pressure within the cooling cycle, temperature within the cooling cycle, and electrical power of an inverter of the heat pump; and controlling the bypass valve based on the collected one or more physical system parameters and one or more preset thresholds. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of a heat pump including a cooling cycle in heating mode.

[0036] Figure 2 Schematically illustrated is a schematic diagram of a heat pump including a cooling cycle in cooling mode.

[0037] Figure 3Schematic diagram of a heat pump that can be used in heating mode and cooling mode.

[0038] Figure 4 A method for operating a heat pump in heating mode is schematically illustrated.

[0039] Figure 5 A method for operating a heat pump in cooling mode is schematically illustrated. DETAILED DESCRIPTION

[0040] Figure 1 The schematic diagram of a heat pump in heating mode, including a cooling cycle, is shown. The cooling cycle includes a compressor 11, a first heat exchanger 12, a third heat exchanger 16, a second expansion valve 13b, and a second heat exchanger 14, wherein these components are sequentially connected to form a loop via fluid piping. In heating mode, the cooling cycle also includes an internal heat exchanger 15 having a first conduit 15a and a second conduit 15b. The first conduit 15a is in heat exchange contact with the second conduit 15b, and the first conduit forms the fluid conduit between the third heat exchanger 16 and the second expansion valve 13b, while the second conduit 15b forms the fluid conduit between the second heat exchanger 14 and the compressor 11.

[0041] In heating mode, the compressor is configured to compress the refrigerant in the cooling cycle. The first heat exchanger, acting as a condenser, is configured to transfer the refrigerant's thermal energy to the fluid circuit to be heated. The third heat exchanger is configured to reduce the temperature of the refrigerant delivered from the first heat exchanger to the internal heat exchanger by releasing heat to the second physical medium. The second expansion valve 13b is configured to reduce the refrigerant's pressure after passing through the expansion valve. The second heat exchanger acts as an evaporator, evaporating the refrigerant by adding the first physical medium's thermal energy to the refrigerant.

[0042] The third heat exchanger 16 reduces the temperature of the refrigerant flowing through the first conduit 15a of the internal heat exchanger. Consequently, the amount of heat transferred from the first conduit 15a to the second conduit 15b in the internal heat exchanger 15 is reduced. As a result, the refrigerant delivered to the compressor has a lower temperature due to a lower suction gas superheat. By reducing suction gas superheat, the compressor envelope parameter performance range at high compression ratios is improved.

[0043] In some embodiments, the third heat exchanger 16 may be arranged near the second heat exchanger 14. Therefore, the second heat exchanger 14 may utilize the waste heat of the third heat exchanger 16. Specifically, the heat provided by the third heat exchanger 16 can be used to prevent ice from forming on at least a portion of the second heat exchanger 14, in particular, "glacial ice." In some embodiments, the second heat exchanger may include a first finned tube for heat exchange between the refrigerant and the air and / or water and / or other physical media, and / or the third heat exchanger may include a second finned tube for heat exchange between the refrigerant and the air and / or water and / or other physical media. Advantageously, as Figure 1 As shown, from a plan view, at least a partial section of the first fin tube (especially the entire first fin tube) can be arranged above at least a partial section of the second fin tube (especially the entire second fin tube).

[0044] However, in some embodiments, the second heat exchanger 14 and the third heat exchanger 16 may be spaced apart from each other, in particular such that no or ineffective heat exchange occurs therebetween, especially when the first and second physical media are different.

[0045] In some embodiments, the heat pump may include a third finned tube, wherein a first section of the third finned tube may include at least a portion of the second heat exchanger 14, and a second section of the third finned tube may include at least a portion of the third heat exchanger 16. Depending on the embodiment, the first section of the third finned tube and the second section of the third finned tube may be adjacent to each other, intersect each other, or be spaced apart from each other within the third finned tube. The third finned tube may have a single shell structure.

[0046] Preferably, when viewed from above, at least a portion of the first section of the third finned tube (particularly the entire first section of the third finned tube) may be arranged above at least a portion of the second section of the third finned tube (particularly the entire second section of the third finned tube). In some embodiments, at least a portion of the second section of the third finned tube may be arranged on the bottom side of the third finned tube.

[0047] like Figure 1 As shown, the cooling cycle may further include a three-way valve 20 and a bypass of the third heat exchanger in heating mode, wherein the heat pump is configured to control the flow through the bypass of the third heat exchanger and the third heat exchanger via the three-way valve, such that the refrigerant temperature delivered to the compressor input in heating mode is lower than a third preset temperature and / or the refrigerant temperature delivered to the compressor input in heating mode is higher than a fourth preset temperature. As a result, the refrigerant temperature delivered to the compressor can be optimized based on the operating point or operating range of the compressor. In some embodiments, the three-way valve may be implemented as a two-way valve, a one-way valve, and / or a flow resistance.

[0048] Advantageously, the third and / or fourth preset temperature may be preset according to the operating point, operating range, and / or physical properties of the refrigerant in the cooling cycle of the compressor and / or heat pump.

[0049] Figure 2 The schematic diagram of a heat pump in cooling mode is shown, including a cooling cycle connected in sequence via fluid piping to form a loop. In cooling mode, the cooling cycle includes a compressor 11, a second heat exchanger 14, a first expansion valve 13a, and a first heat exchanger 12. In cooling mode, the cooling cycle may also include an internal heat exchanger 15, wherein a first conduit 15a of the internal heat exchanger constitutes the fluid piping portion between the second heat exchanger 14 and the first expansion valve 13a, and a second conduit 15b of the internal heat exchanger 15 constitutes the fluid piping portion between the first heat exchanger 12 and the compressor.

[0050] In cooling mode, the compressor is configured to compress the refrigerant in the cooling cycle, the first heat exchanger acts as an evaporator and is configured to add heat energy from the fluid circuit to the refrigerant. The first expansion valve 13a is configured to reduce the pressure of the refrigerant after it passes through the expansion valve, and the second heat exchanger acts as a condenser, condensing the refrigerant by releasing its heat energy to a third physical medium.

[0051] Optionally, the cooling circuit may comprise a bypass of the first conduit 15a of the internal heat exchanger 15, wherein the bypass of the first conduit 15a is constituted by a fluid line comprising a bypass valve 17. The bypass valve may be a controllable valve, in particular a controllable ball valve.

[0052] By providing a bypass of the first conduit and a bypass valve within the first conduit, heat transfer from the first conduit 15a to the second conduit 15b of the internal heat exchanger 15 can be controlled. Consequently, the temperature of the refrigerant supplied from the second conduit 15b of the internal heat exchanger 15 to the compressor 11 can be reduced. This improves the performance range of the compressor envelope parameters in the high compression ratio region by controlling the suction gas superheat.

[0053] In some embodiments, the heat pump can be configured to control the bypass valve so that the temperature of the refrigerant delivered to the input end of the compressor in cooling mode is lower than a first preset temperature and / or higher than a second preset temperature.

[0054] The first preset temperature and / or the second preset temperature may be preset according to the operating point of the compressor and / or the heat pump, and / or the operating range of the compressor and / or the heat pump, and / or the physical properties of the refrigerant in the cooling cycle.

[0055] In some embodiments, the bypass of the third heat exchanger may be achieved by a three-way valve to replace the bypass valve having the same technical effect.

[0056] Figure 3 Schematic diagram of a heat pump that can be used in heating mode and cooling mode. Figure 3 The heat pump shown is based on Figure 1 and Figure 2 The heat pump is configured to switch between a heating mode and a cooling mode, wherein a cooling cycle includes a four-way valve 18, a first check valve 19a, and a second check valve 19b for switching between the heating mode and the cooling mode.

[0057] The four-way valve 18 is configured to connect the fluid line from the compressor outlet to the first heat exchanger and the fluid line from the second heat exchanger to the second conduit 15b of the internal heat exchanger 15 in heating mode. In cooling mode, it connects the fluid line from the compressor outlet to the second heat exchanger and the fluid line from the first heat exchanger to the second conduit 15b of the internal heat exchanger 15. The first expansion valve is bypassed in the direction from the first heat exchanger to the first conduit 15a of the internal heat exchanger 15 by a fluid line including the third heat exchanger 16 and the first check valve 19a. The second expansion valve is bypassed in the direction from the second heat exchanger to the first conduit of the internal heat exchanger by a fluid line including the second check valve 19b.

[0058] This provides a flexible Figure 1 The heating mode shown and Figure 2 Heat exchanger shown in cooling mode.

[0059] As mentioned above, a fluid line can be optionally provided to bypass the first conduit 15a of the internal heat exchanger 15. The bypass of the first conduit 15a can include a bypass valve 17 or other components to control the flow through the bypass of the first conduit 15a and the flow in the first conduit 15a.

[0060] Again optionally, as Figure 1 As described above, the cooling cycle may further include a three-way valve 20 and a bypass of the third heat exchanger in the heating mode. The three-way valve 20 controls the flow rate of the bypass of the third heat exchanger and the flow rate of the third heat exchanger so that the temperature of the refrigerant delivered to the input end of the compressor in the heating mode is lower than the third preset temperature and / or the temperature of the refrigerant delivered to the input end of the compressor in the heating mode is higher than the fourth preset temperature.

[0061] In some embodiments, the first preset temperature and the third preset temperature may be the same or different. In some embodiments, the second preset temperature and the fourth preset temperature may be the same or different.

[0062] In some embodiments, the first expansion valve may be an electronic expansion valve and / or a thermal expansion valve. Preferably, the first expansion valve may be electronically controllable. In some embodiments, the second expansion valve may be an electronic expansion valve and / or a thermal expansion valve. Preferably, the second expansion valve may be electronically controllable.

[0063] Examples of the first, second, and / or third physical media include, but are not limited to, air, water, salt water, and soil. In some embodiments, the first and second physical media may be the same or different; the first and third physical media may be the same or different; and / or the third and second physical media may be the same or different.

[0064] Preferably, the heat pump may be one or more of the following group: an air-to-water heat pump, a ground source heat pump, and a brine-to-water heat pump.

[0065] In some embodiments, the first, second, third, and / or fourth preset temperatures may be preset based on an operating point of the compressor, an operating range of the compressor, and / or physical properties of a refrigerant in a cooling cycle.

[0066] In some embodiments, the first, second, third and / or fourth preset temperatures may be constant values. In some embodiments, the first, second, third and / or fourth preset temperatures may be preset according to a temperature difference of the internal heat exchanger, in particular additionally preset.

[0067] The temperature difference of the internal heat exchanger can be: the temperature difference between the input end of the first conduit and the output end of the second conduit, the temperature difference between the input end of the first conduit and the output end of the first conduit, and the temperature difference between the input end of the second conduit and the output end of the second conduit. In some embodiments, the first, second, third, and / or fourth preset temperatures can be determined based on one or more measured temperatures.

[0068] The measured temperatures may be, for example: an input temperature of a first conduit of the internal heat exchanger, an output temperature of the first conduit of the internal heat exchanger, an input temperature of a second conduit of the internal heat exchanger, and an output temperature of the second conduit of the internal heat exchanger.

[0069] Figure 4A method for operating a heat pump in heating mode is schematically illustrated. The heat pump includes a cooling cycle. In heating mode, the cooling cycle includes: a compressor; an internal heat exchanger configured to transfer heat from a high-pressure section of the cooling cycle of the heat pump to a low-pressure section of the cooling cycle before the refrigerant enters an input of the compressor located in the low-pressure section of the cooling cycle. The cooling cycle also includes a third heat exchanger configured to cool the refrigerant before the refrigerant enters the high-pressure section of the internal heat exchanger; a bypass of the third heat exchanger; and a three-way valve configured to control flow to the third heat exchanger and flow bypassing the third heat exchanger.

[0070] The method includes the following steps: (S41) collecting one or more physical system parameters of the heat pump, wherein the one or more physical system parameters include one or more of the following: pressure within the cooling cycle, temperature within the cooling cycle, and electrical power of an inverter of the heat pump. The method further includes the following steps: (S42) controlling a three-way valve based on the collected one or more physical system parameters and one or more preset threshold values. The preset threshold values are set so that the heat pump operates in a preset operating point and / or a preset operating range in a heating mode, wherein the preset operating point and / or the preset operating range are characterized by the preset threshold values.

[0071] Figure 5 A method for operating a heat pump in cooling mode is schematically illustrated. The heat pump includes a cooling cycle that, in cooling mode, includes a compressor; and an internal heat exchanger configured to transfer heat from a high-pressure section of the heat pump's cooling cycle to a low-pressure section of the cooling cycle before the refrigerant enters an input of the compressor in the low-pressure section of the cooling cycle. The cooling cycle also includes a bypass of the high-pressure section of the internal heat exchanger. The bypass of the high-pressure section of the internal heat exchanger includes a bypass valve configured to control the flow of refrigerant through the internal heat exchanger on the high-pressure section of the heat pump's cooling cycle and the flow of refrigerant bypassing the high-pressure section of the internal heat exchanger.

[0072] The method includes the following steps: (S51) collecting one or more physical system parameters of the heat pump, including one or more of the following: pressure within the cooling cycle, temperature within the cooling cycle, and electrical power of an inverter of the heat pump. The method further includes the following steps: (S52) controlling a bypass valve based on the collected one or more physical system parameters and one or more preset thresholds. The preset thresholds are set so that the heat pump operates in a cooling mode within a preset operating point and / or a preset operating range, wherein the preset operating point and / or the preset operating range are characterized by the preset thresholds.

[0073] Preferably, using Figure 4 The method described can be used with Figure 5The methods are combined to control the suction superheat of the heat pump in heating mode and cooling mode.

[0074] In some embodiments, particularly in the above Figures 1 to 5 In the embodiments of the present invention, one or more units may be added, combined, split or omitted without affecting the technical teachings of the present patent application. In some embodiments, especially in the above Figures 1 to 5 In the embodiments, one or more method steps may be split, combined, added and / or omitted without affecting the technical teachings of this patent application.

[0075] In some embodiments, without affecting the technical teachings described in this patent application, the functions of one or more components can be implemented by one or more different components that have the same technical effect.

[0076] In some embodiments, a computer program product may include a plurality of instructions that, when executed by a computer, cause the computer to perform one or more of the above methods.

Claims

1. A heat pump comprising a cooling cycle, characterized in that The cooling cycle includes the following fluid pipes connected in sequence to form a loop in the heating mode: -compressor, - a first heat exchanger, - a third heat exchanger, - a second expansion valve, and - a second heat exchanger, The cooling cycle in heating mode further includes: an internal heat exchanger having a first conduit and a second conduit, the first conduit being in heat-exchanging contact with the second conduit, wherein the first conduit is part of the fluid line between the third heat exchanger and the second expansion valve, and the second conduit is part of the fluid line between the second heat exchanger and the compressor, In heating mode: The compressor is configured to compress the refrigerant in the cooling cycle, The first heat exchanger is a condenser and is configured to add thermal energy from the refrigerant to the fluid circuit to be heated, The third heat exchanger is configured to reduce the temperature of the refrigerant delivered from the first heat exchanger to the internal heat exchanger by releasing heat to the second physical medium, The second expansion valve is configured to reduce the pressure of the refrigerant after the refrigerant passes through the expansion valve, and The second heat exchanger is an evaporator that evaporates the refrigerant by adding heat energy of the first physical medium to the refrigerant.

2. The heat pump according to claim 1, characterized in that The cooling cycle includes: - the compressor, - the second heat exchanger, - first expansion valve, - the first heat exchanger, The cooling cycle further comprises, in cooling mode: - the internal heat exchanger, wherein the first conduit is part of the fluid line between the second heat exchanger and the first expansion valve, and the second conduit is part of the fluid line between the first heat exchanger and the compressor, In cooling mode: The compressor is configured to compress the refrigerant in the cooling cycle, The first heat exchanger is an evaporator and is configured to add thermal energy of the fluid circuit to the refrigerant, The first expansion valve is configured to reduce the pressure of the refrigerant after the refrigerant passes through the expansion valve. The second heat exchanger is a condenser that condenses the refrigerant by releasing the heat energy of the refrigerant to the third physical medium, wherein The heat pump is configured to switch between a heating mode and a cooling mode, and the cooling cycle includes: - Four-way valve, - a first one-way valve, and - a second non-return valve, in The four-way valve is configured to connect the fluid line from the compressor outlet to the first heat exchanger and connect the fluid line from the second heat exchanger to the second conduit of the internal heat exchanger in heating mode; and to connect the fluid line from the compressor outlet to the second heat exchanger and connect the fluid line from the first heat exchanger to the second conduit of the internal heat exchanger in cooling mode. The first expansion valve is bypassed in the direction of the first conduit from the first heat exchanger to the internal heat exchanger by a fluid line including the third heat exchanger and the first non-return valve, The second expansion valve is bypassed in the direction of the first conduit from the second heat exchanger to the internal heat exchanger by a fluid line including the second non-return valve.

3. The heat pump according to claim 2, characterized in that The first conduit of the internal heat exchanger is bypassed by a fluid line comprising a bypass valve, in particular a controllable valve.

4. The heat pump according to claim 3, characterized in that The heat pump is configured to control the bypass valve so that the temperature of the refrigerant delivered to the input end of the compressor in the cooling mode is lower than a first preset temperature; and / or so that the temperature of the refrigerant delivered to the input end of the compressor in the cooling mode is higher than a second preset temperature.

5. The heat pump according to any one of claims 1 to 4, It is characterized by: The cooling cycle in heating mode also includes: Three-way valve, and The bypass of the third heat exchanger, wherein The heat pump is configured to control the flow rate flowing through the third heat exchanger and the bypass flowing through the third heat exchanger through the three-way valve, so that the temperature of the refrigerant delivered to the input end of the compressor in the heating mode is lower than a third preset temperature; and / or, the temperature of the refrigerant delivered to the input end of the compressor in the heating mode is higher than a fourth preset temperature.

6. The heat pump according to claim 4 or 5, characterized in that One or more of the following group are preset constant values: the first preset temperature, the second preset temperature, the third preset temperature, the fourth preset temperature; and / or One or more of the following group is determined based on the temperature difference of the internal heat exchanger: the first preset temperature, the second preset temperature, the third preset temperature, and the fourth preset temperature; wherein the temperature difference of the internal heat exchanger specifically includes at least one of the following group: - a temperature difference between the input end of the first conduit and the output end of the second conduit, - a temperature difference between the input end of the first conduit and the output end of the first conduit, and - a temperature difference between the input end of the second conduit and the output end of the second conduit; and / or One or more of the following group is determined based on the measured temperature: the first preset temperature, the second preset temperature, the third preset temperature, the fourth preset temperature; wherein the measured temperature specifically includes at least one of the following group: an input temperature of the first conduit of the internal heat exchanger; an output temperature of the first conduit of the internal heat exchanger; an input temperature of the second conduit of the internal heat exchanger; and The output temperature of the second conduit of the internal heat exchanger.

7. The heat pump according to any one of claims 1 to 6, characterized in that The first expansion valve is an electronic expansion valve and / or a thermal expansion valve; and / or The second expansion valve is an electronic expansion valve and / or a thermal expansion valve.

8. The heat pump according to any one of claims 1 to 7, characterized in that The first physical medium and / or the second physical medium and / or the third physical medium is one or more of the following group: Air, water, Salt water, and soil; and / or The heat pump is one or more of the following groups: - air-to-water heat pumps, - Ground source heat pumps, and -Brine-water heat pump.

9. The heat pump according to any one of claims 1 to 8, characterized in that The second heat exchanger comprises a first finned tube for heat exchange between the refrigerant and the air and / or water; and / or The third heat exchanger includes second finned tubes for heat exchange between the refrigerant and air and / or water.

10. The heat pump according to claim 9, characterized in that From a top view, at least a portion of the first fin tube is disposed above at least a portion of the second fin tube.

11. The heat pump according to any one of claims 1 to 8, characterized in that include: The third finned tube, wherein The first section of the third finned tube comprises at least a portion of the second heat exchanger, and The second section of the third finned tube includes at least a portion of the third heat exchanger.

12. The heat pump according to claim 11, characterized in that From a top view, at least part of the first section of the third finned tube is arranged above at least part of the second section of the third finned tube; and / or at least part of the second section of the third finned tube is arranged on the bottom side of the third finned tube.

13. A method for operating a heat pump according to any one of claims 1 to 12.

14. A method of operating a heat pump, characterized in that The heat pump includes a cooling cycle, which in heating mode includes: compressor, an internal heat exchanger configured to transfer heat from the high-pressure section of the cooling cycle of the heat pump to the low-pressure section of the cooling cycle before the refrigerant enters the input of the compressor located in the low-pressure section of the cooling cycle, a third heat exchanger configured to cool the refrigerant before it enters the high pressure section of the internal heat exchanger, a bypass of the third heat exchanger, and A three-way valve is configured to control the flow to the third heat exchanger and the flow of the third heat exchanger being bypassed, The method comprises the following steps in the heating mode: collecting one or more physical system parameters of the heat pump, the one or more physical system parameters comprising one or more of the following group: pressure within the cooling cycle, temperature within the cooling cycle, and electrical power of an inverter of the heat pump; The three-way valve is controlled based on the collected one or more physical system parameters and one or more preset thresholds.

15. The method according to claim 14, characterized in that The cooling cycle in cooling mode comprises: the compressor, the internal heat exchanger being configured to transfer heat from the high pressure section of the cooling cycle of the heat pump to the low pressure section of the cooling cycle before the refrigerant enters the input of the compressor located in the low pressure section of the cooling cycle, and a bypass of the high-pressure section of the internal heat exchanger, the bypass comprising a bypass valve configured to control a flow rate of refrigerant flowing through the internal heat exchanger located on the high-pressure section in the cooling cycle of the heat pump and a flow rate of refrigerant flowing through the bypass of the high-pressure section of the internal heat exchanger, The method comprises the following steps in cooling mode: collecting one or more physical system parameters of the heat pump, including one or more of the following group: pressure in the cooling cycle, temperature in the cooling cycle, and electrical power of an inverter of the heat pump; The bypass valve is controlled based on the acquired one or more physical system parameters and one or more preset thresholds.

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