Heat pump and method of controlling a heat pump

Abstract

The present invention relates to a heat pump (1) and a method for controlling the heat pump, the heat pump having a heating mode and a cooling mode and including a refrigerant circuit (200) and a hydraulic circuit (100), the refrigerant circuit including a refrigerant configured to circulate through the refrigerant circuit, a compressor (12), an internal heat exchanger (10), and a directional valve (14), particularly a 4 / 2-way valve, wherein the internal heat exchanger is configured to exchange heat between the refrigerant and a hydraulic fluid configured to circulate through the hydraulic circuit, and the directional valve is configured to reverse the flow direction of the refrigerant in the refrigerant circuit to switch between the heating mode and the cooling mode, the heat pump also including a second directional valve (50) configured to reverse the flow direction of the refrigerant or hydraulic fluid through the internal heat exchanger, such that the refrigerant and the hydraulic fluid flow countercurrently through the internal heat exchanger in the heating mode and the cooling mode.

Description

Technical Field

[0001] The present invention relates to a heat pump having a heating mode and a cooling mode, and a method for controlling such a heat pump.

[0002] The present invention also relates to a computer-readable storage medium storing program code including instructions for performing such a method. Background Technology

[0003] Heat pumps are widely known. A heat pump is a system designed to transfer heat from one place to another for heating or cooling purposes. Heat pumps operate based on thermodynamic principles and use electricity not to generate heat but to transfer it. The process begins in an evaporator, where heat is absorbed from an external source such as air, ground, or water. Then, a compressor raises the temperature of the refrigerant, which carries the heat to the condenser, where the heat is released into the desired space. The cycle is complete as the refrigerant passes through an expansion valve to reduce its pressure and prepare to absorb heat again.

[0004] Heat pumps come in different types, including air-source systems (extracting heat from the air), ground-source (geothermal) systems (using the ground as a heat source), and water-source systems. They are highly energy efficient and transfer up to three to four times the energy they consume, making them an environmentally friendly option for both heating and cooling. Additionally, many systems can also heat water, further increasing their versatility. With a smaller carbon footprint and compatibility with renewable energy sources, heat pumps are becoming the preferred solution for residential and commercial applications.

[0005] The reversal of the refrigerant flow direction in a heat pump allows it to switch between heating and cooling modes, making it a versatile system for year-round climate control. This process can be achieved through a reversing valve, a key component that changes the direction of refrigerant flow within the system.

[0006] In heating mode, the heat pump extracts heat from an external source (such as air, ground, or water) and transfers it to the room. The evaporator absorbs heat from the external environment, the compressor raises the temperature of the refrigerant, and the condenser releases the heat into the interior space.

[0007] When switching to cooling mode, the flow direction is reversed. The indoor unit, or indoor heat exchanger, now acts as an evaporator, absorbing heat from the indoor air, while the outdoor unit becomes a condenser, releasing that heat to the outside. The refrigerant follows this reversed path to ensure efficient heat removal, thus keeping the indoor environment cool.

[0008] This capability makes heat pumps a practical and energy-efficient solution for heating during cold months and cooling during warmer seasons to seamlessly adapt to changing temperature demands.

[0009] However, reversing the refrigerant flow direction is not without its challenges. In particular, the efficiency of the internal heat exchanger will deteriorate due to the reversal of the flow direction.

[0010] Furthermore, the reversal of the flow direction is not only used for switching between heating and cooling operations. For example, it is known to be used for defrosting external heat exchangers or condensers that may accumulate ice under certain environmental conditions.

[0011] Therefore, the object of the present invention is to improve a heat pump capable of both heating and cooling. Summary of the Invention

[0012] The object of the present invention is to provide a heat pump having a heating mode and a cooling mode, and a method for controlling the heat pump as described herein, which overcomes one or more of the aforementioned problems of the prior art.

[0013] A first aspect of the invention provides a heat pump having a heating mode and a cooling mode, the heat pump comprising: a refrigerant circuit and a hydraulic circuit, the refrigerant circuit including a refrigerant configured to circulate through the refrigerant circuit, a compressor, an internal heat exchanger, and a directional valve, particularly a 4 / 2-way valve, wherein the internal heat exchanger is configured to exchange heat between the refrigerant and a hydraulic fluid configured to circulate through the hydraulic circuit, and the directional valve is configured to reverse the flow direction of the refrigerant in the refrigerant circuit to switch between the heating mode and the cooling mode.

[0014] The heat pump also includes a second directional valve configured to reverse the flow direction of the refrigerant or hydraulic fluid through the internal heat exchanger, so that the refrigerant and hydraulic fluid flow in a counter-current manner through the internal heat exchanger in heating and cooling modes.

[0015] The internal heat exchanger is preferably operated in a counter-current flow manner to maximize energy transfer efficiency. In this setup, two fluids (e.g., hot and cold fluids) flow in opposite directions to create a continuous temperature gradient along the exchanger.

[0016] This configuration ensures that the temperature difference between the fluids remains relatively high throughout the entire length of the heat exchanger. Therefore, more heat is transferred, and the heat exchange process is more efficient. Furthermore, counter-current flow allows the two fluids to approach the desired outlet temperature more closely compared to parallel flow systems.

[0017] By maintaining the optimal temperature gradient, countercurrent operation improves performance, reduces energy waste, and is particularly useful in applications requiring precise temperature control or maximum heat recovery.

[0018] With the aid of a second directional valve, the flow through the internal heat exchanger can be counter-current in both heating and cooling operations of the heat pump. Simultaneously, this flow can also be parallel, for example, during defrosting operations. In the defrosting mode of the heat pump, parallel flow through the internal heat exchanger is preferred to improve system performance and efficiency. During defrosting, the goal is to remove ice or frost accumulated on the outdoor unit by reversing the heat pump's circulation to direct heat from the system to the outdoor coil.

[0019] In a first implementation of the heat pump according to the first aspect, the hydraulic circuit includes a circulation pump that circulates hydraulic fluid between a hydraulic circuit supply line and a hydraulic circuit return line, wherein a second directional valve is arranged in the hydraulic circuit such that the flow direction of the hydraulic fluid through the internal heat exchanger can be reversed without reversing the flow directions of the supply and return lines.

[0020] In another implementation of the heat pump according to the first aspect, the second directional valve includes two 3 / 2-way valves respectively arranged before and after the internal heat exchanger.

[0021] In another implementation of the heat pump according to the first aspect, each of the two 3 / 2-way valves is connected to the two hydraulic side inlets of the internal heat exchanger, such that switching the switching position of the 3 / 2-way valves reverses the flow of hydraulic fluid through the internal heat exchanger.

[0022] In another implementation of the heat pump according to the first aspect, the second directional valve includes a 4 / 2-way valve connected to two hydraulic side inlets of the internal heat exchanger, such that switching the 4 / 2-way valve to a different position reverses the flow of hydraulic fluid through the internal heat exchanger.

[0023] Considering the number of components and cost, a 4 / 2-way valve is superior to a 3 / 2-way valve. However, a 3 / 2-way valve is preferred because heat is not transferred internally between the hot and cold fluids within the valve, which would reduce the efficiency of the heat pump.

[0024] In another implementation of the heat pump according to the first aspect, a second directional valve is arranged in the refrigerant circuit such that the flow direction of the refrigerant through the internal heat exchanger is reversible.

[0025] In another implementation of the heat pump according to the first aspect, the second directional valve includes a 4 / 2-way valve or two 3 / 2-way valves connected to the two refrigerant-side inlets of the internal heat exchanger.

[0026] In another implementation of the heat pump according to the first aspect, the hydraulic circuit further includes at least one of the following:

[0027] - An inverter cooler configured to dissipate heat from the inverter of the heat pump, and

[0028] - Auxiliary heaters, especially resistance heaters.

[0029] In another implementation of the heat pump according to the first aspect, the refrigerant circuit further includes at least one of the following:

[0030] - External heat exchangers, especially air-to-water heat exchangers including fans,

[0031] -Throttling devices, especially expansion valves

[0032] -Regenerator,

[0033] - A hot gas injection device for injecting hot gas into the compressor.

[0034] - Defrosting coils, and

[0035] - Refrigerant collector.

[0036] This invention can be combined with all implementations of different refrigeration circuits known to those skilled in the art. Those skilled in the art will design the refrigerant circuit according to the requirements of a specific application.

[0037] While those skilled in the art will understand that the invention is particularly applicable to heat pumps that use ambient air as a heat source, they will also understand that other forms of heat source, such as water, are conceivable. Furthermore, the invention is applicable to both indoor and outdoor heat pumps.

[0038] The method according to the second aspect of the invention can be performed by a heat pump having a heating mode and a cooling mode according to the first aspect of the invention. Other features or implementations of the method according to the second aspect of the invention can perform the functions of a heat pump having a heating mode and a cooling mode according to the first aspect of the invention and its different implementations.

[0039] In another implementation of the second aspect of the method, the second directional valve is controlled to switch its operating position according to at least one of the following:

[0040] - The switching position of the directional valve in the refrigerant circuit

[0041] - The switching position of the inverter cooler valve, and

[0042] - Heat Pump Manager: This manager sets the operating modes of the heat pump, including heating mode and cooling mode.

[0043] In particular, the switching position of the inverter cooling valve is preferred because inverter cooling is avoided in special operating modes such as defrosting. Therefore, the control of the second directional valve can be easily integrated into the control of the heat pump.

[0044] Another aspect of the invention relates to a computer-readable storage medium storing program code, the program code including instructions that execute when a processor performs the method of the second aspect or a method of one embodiment of the second aspect. Attached Figure Description

[0045] To more clearly illustrate the technical features of the embodiments of the present invention, the accompanying drawings provided for describing the embodiments are briefly described below. The drawings in the following description are merely some embodiments of the present invention, and modifications can be made to these embodiments without departing from the scope of the invention as defined in the claims.

[0046] Figure 1 This diagram illustrates a heat pump with both heating and cooling modes in heating mode, which helps in understanding the invention.

[0047] Figure 2 The diagram shows the device in cooling mode. Figure 1 A diagram of a heat pump is provided to aid in understanding the invention.

[0048] Figure 3A This is a diagram illustrating a heat pump according to an embodiment of the present invention.

[0049] Figure 3B The diagram shows the device in cooling mode. Figure 3A The diagram shows the implementation method.

[0050] Figure 4A This is a diagram illustrating a heat pump according to another embodiment of the present invention.

[0051] Figure 4B The diagram shows the device in cooling mode. Figure 4A The diagram shows the implementation method.

[0052] Figure 5A This is a diagram illustrating a heat pump according to another embodiment of the present invention, and

[0053] Figure 5B The diagram shows the device in cooling mode. Figure 5A A diagram illustrating the implementation method. Detailed Implementation

[0054] Figure 1 The illustration shows a heat pump 1000 in heating mode, which helps in understanding the invention. The heat pump 1000 includes a hydraulic circuit 100 and a refrigerant circuit 200.

[0055] In the hydraulic circuit 100, hydraulic fluid is circulated, for example by means of a circulation pump 130, to the heating space between the feed line or supply line 110 and the output line or return line 120. An optional auxiliary heater 140 is arranged in the supply line 110, which can heat the hydraulic fluid using electrical energy if necessary. Furthermore, an optional inverter cooler 150 is provided for dissipating heat from the inverter of the heat pump 1000, wherein the flow to the inverter cooler 150 can be regulated using a controllable valve 160.

[0056] Hydraulic fluid and refrigerant exchange heat in an internal heat exchanger 10, which can operate as both a condenser and an evaporator depending on the flow direction of the refrigerant through the refrigerant circulation that occurs in the refrigerant circuit 200.

[0057] The refrigerant circuit 200 includes a compressor 12, a directional valve 14, an external heat exchanger 16, and an expansion valve 18. In the illustrated heating mode, the refrigerant circulates from the external heat exchanger 16, where it absorbs heat from a heat source, to the compressor 12, which compresses the refrigerant, and then to the internal heat exchanger 10, where heat is transferred to the hydraulic fluid in the hydraulic circuit 100. Finally, the refrigerant is released by means of the expansion valve 18, and the cycle is complete.

[0058] The refrigerant circuit 200 also includes other elements of the heating circuit, which will be described below. It should be noted that other embodiments of the heating circuit can be combined with the invention, i.e., many of the described components are optional.

[0059] In this example, the refrigerant circuit 200 includes a regenerator 20, which is controllable by valve 22 and allows hot gas injection device 24 to reach compressor 12. Additionally, a refrigerant collector 26 and a filter dryer 28 are provided. A defrost coil 30 is configured to defrost the external heat exchanger 16 when necessary. Several other valves 32 and 34 are provided, which specifically control the flow direction through certain portions of the hydraulic circuit 100. In particular, the refrigerant collector 26 and filter dryer 28 are preferably flowed through in only one direction, i.e., they should not be affected if the refrigerant flow direction is reversed.

[0060] In this example, heat pump 1000 is an air-to-water heat pump with a fan-driven evaporator as an external heat exchanger 16, where other heat sources can of course also be envisioned.

[0061] Figure 2 The diagram shows the device in cooling mode. Figure 1The heat pump 1000. In this example, the operating position of the directional valve 14 is changed, causing the flow of refrigerant through the refrigerant circuit 200 to be reversed. It can be seen that the internal heat exchanger 10 is flowed through in parallel, that is, the flow direction of the refrigerant in the refrigerant circuit 200 is parallel to the flow direction of the hydraulic fluid in the hydraulic circuit 100.

[0062] Figure 3A and Figure 3B A heat pump 1 according to an embodiment of the present invention is shown. Except for the provision of a second directional valve 50 in the hydraulic circuit 100, the heat pump 1 corresponds to... Figure 1 and Figure 2 The heat pump 1000 is shown in the figure. Figure 3A The diagram illustrates the heating process, and Figure 3B The same implementation is illustrated in the cooling operation.

[0063] In this embodiment, the second directional valve 50 includes a first 3 / 2-way valve 52 and a second 3 / 2-way valve 54 respectively disposed between the internal heat exchanger 10 and the controllable valve 160 or the pump 130. The first 3 / 2-way valve 52 and the second 3 / 2-way valve 54 have two operating positions. Figure 3A In the illustrated operating position, the first 3 / 2-way valve 52 supplies hydraulic fluid to the inlet 53 located on the left side of the illustrated internal heat exchanger 10. Correspondingly, the second 3 / 2-way valve 54 supplies hydraulic fluid from the inlet 55 on the right side of the illustrated position. Thus, as illustrated, the hydraulic fluid flows from left to right through the internal heat exchanger 10.

[0064] By changing the operating positions of both the first 3 / 2-way valve 52 and the second 3 / 2-way valve 54, the flow direction is reversed, such as... Figure 3B As illustrated. More precisely, the first 3 / 2-way valve 52 now supplies hydraulic fluid to the right inlet 55, and the second 3 / 2-way valve 54 supplies hydraulic fluid from the left inlet 53. Therefore, the flow direction of the hydraulic fluid is reversed and is now from right to left as illustrated.

[0065] As from Figure 3A and Figure 3B As can be seen, in the reference Figure 3A Heating operation and see Figure 3B In both cooling operations, the flow of hydraulic fluid and the flow of refrigerant are in countercurrent. Therefore, the second directional valve 50 mirrors the reversal of the refrigerant flow direction by similarly reversing the flow direction of the hydraulic fluid through the internal heat exchanger 10.

[0066] Figure 4A and Figure 4BA heat pump 1 according to an embodiment of the present invention is shown. Except for the alternative second directional valve 50 provided in the hydraulic circuit 100, the heat pump 1 corresponds to... Figure 3A and Figure 3B The implementation method. Figure 4A The diagram illustrates the heating process, and Figure 4B The same implementation is illustrated in the cooling operation.

[0067] In this embodiment, the second directional valve 50 includes a single 4 / 2-way valve 60. (As from...) Figure 4A and Figure 4B As can be understood from the comparison, changing the operating position of the 4 / 2-way valve 60 causes the hydraulic fluid to flow in the direction of the internal heat exchanger 10 in a manner consistent with... Figure 3A and Figure 3B The implementation method has been changed in the same way.

[0068] A single 4 / 2-way valve is more cost-effective than two separate 3 / 2-way valves. However, the 3 / 2-way valve does not suffer from energy loss due to direct contact between the liquid in supply line 110 and return line 120.

[0069] Figure 5A and Figure 5B A heat pump 1 according to another embodiment of the present invention is shown. Heat pump 1 corresponds to... Figure 1 and Figure 2 The heat pump 1000, wherein the second directional valve 50 is included in the refrigerant circuit 200 instead of the hydraulic circuit 100.

[0070] More specifically, an example includes a 4 / 2-way valve 70 in the refrigerant circuit 200 near the internal heat exchanger 10. Figure 5A and Figure 5B As can be seen from the two different operating positions of the 4 / 2-way valve 70, even when the flow direction of the refrigerant through the refrigerant circuit 200 is reversed by changing the operating position of the directional valve 14, the flow direction of the refrigerant through the internal heat exchanger 10 remains unchanged. Therefore, an implementation using two 3 / 2-way valves can be used instead of one 4 / 2-way valve 70.

[0071] The foregoing description is merely an embodiment of the present invention, and the scope of the invention is not limited thereto. Those skilled in the art can readily make any modifications or substitutions. Therefore, the scope of protection of the present invention should be determined by the scope of the appended claims.

[0072] List of reference numerals

[0073] 1. Heat pump

[0074] 10 Internal heat exchanger

[0075] 12 Compressors

[0076] 14 Directional valve

[0077] 16 External heat exchangers

[0078] 18 Expansion valve

[0079] 20 Regenerator

[0080] 22, 32, 34 valves

[0081] 24. Hot gas injection device

[0082] 26 Specific refrigerant collectors

[0083] 26 Refrigerant Collector

[0084] 28 Filter Dryer

[0085] 30 Defrosting Coil

[0086] 50 Second Directional Valve

[0087] 52, 54 3 / 2-way valves

[0088] Entrances 53 and 55

[0089] 60, 70 4 / 2-way valve

[0090] 100 Hydraulic Circuit

[0091] 110 Supply Line

[0092] 120 Return Pipeline

[0093] 130 circulating pump

[0094] 140 Optional auxiliary heater

[0095] 150 Optional Inverter Coolers

[0096] 160 controllable valve

[0097] 200 refrigerant circuit

[0098] 1000 heat pump

Claims

1. A heat pump (1) having a heating mode and a cooling mode, the heat pump (1) comprising: Refrigerant circuit (200) and hydraulic circuit (100), The refrigerant circuit (200) includes a refrigerant, a compressor (12), an internal heat exchanger (10), and a directional valve (14), particularly a 4 / 2-way valve, wherein the refrigerant is configured to circulate through the refrigerant circuit (200), wherein, The internal heat exchanger (10) is configured to exchange heat between the refrigerant and the hydraulic fluid configured to circulate through the hydraulic circuit (100), and The directional valve (14) is configured to reverse the flow direction of the refrigerant in the refrigerant circuit (200) to switch between the heating mode and the cooling mode. The heat pump (1) is characterized in that it further includes: The second directional valve (50) is configured to reverse the flow direction of the refrigerant or the hydraulic fluid through the internal heat exchanger (10), so that the refrigerant and the hydraulic fluid flow in a countercurrent manner through the internal heat exchanger (10) in the heating mode and the cooling mode.

2. The heat pump (1) according to claim 1, the hydraulic circuit (100) comprising a circulation pump (130) circulating the hydraulic fluid between a hydraulic circuit supply line (110) and a hydraulic circuit return line (120), wherein, The second directional valve (50) is arranged in the hydraulic circuit (100) such that the flow direction of the hydraulic fluid through the internal heat exchanger (10) can be reversed without reversing the flow direction of the hydraulic circuit supply line (110) and the hydraulic circuit return line (120).

3. Heat pump (1) according to claim 2, wherein The second directional valve (50) includes two 3 / 2-way valves (52, 54) respectively arranged before and after the internal heat exchanger (10).

4. The heat pump (1) according to claim 3, wherein, Each of the two 3 / 2-way valves (52, 54) is connected to the two hydraulic side inlets (53, 55) of the internal heat exchanger (10), such that switching the switching position of the 3 / 2-way valves (52, 54) reverses the flow of the hydraulic fluid through the internal heat exchanger (10).

5. The heat pump (1) according to claim 2, wherein, The second directional valve (50) includes a 4 / 2-way valve (60) connected to two hydraulic side inlets (53, 55) of the internal heat exchanger (10), such that switching the position of the 4 / 2-way valve (60) reverses the flow of hydraulic fluid through the internal heat exchanger (10).

6. The heat pump (1) according to claim 1, wherein, The second directional valve (50) is arranged in the refrigerant circuit (200) so that the flow direction of the refrigerant through the internal heat exchanger (10) can be reversed.

7. The heat pump (1) according to claim 6, wherein, The second directional valve (50) includes a 4 / 2-way valve (70) or two 3 / 2-way valves connected to the two refrigerant-side inlets of the internal heat exchanger (10).

8. The heat pump (1) according to any one of the preceding claims, wherein the hydraulic circuit (100) further comprises at least one of the following: Inverter cooler (150), the inverter cooler (150) being configured to dissipate heat from the inverter of the heat pump (1), and Auxiliary heaters (140), especially resistance heaters.

9. The heat pump (1) according to any one of the preceding claims, wherein the refrigerant circuit (200) further comprises at least one of the following: External heat exchangers (16), particularly air-to-water heat exchangers including fans, Throttling devices, especially expansion valves (18), Regenerator (20), A hot gas injection device (24) is provided for injecting hot gas into the compressor (12). Defrosting coil (30), and Refrigerant collector (26).

10. A method for controlling a heat pump (1) according to any one of the preceding claims, wherein, The second directional valve (50) is controlled to switch its operating position according to at least one of the following: The switching position of the directional valve (14) in the refrigerant circuit (200), The switching position of the valve (160) of the inverter cooler (150), and A heat pump manager sets the operating mode of the heat pump (1), which includes a heating mode and a cooling mode.

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