Heat pump system and control method thereof

Abstract

A heat pump system according to an embodiment of the present disclosure includes: a compressor configured to compress a refrigerant; a refrigerant-water heat exchanger in which heat exchange occurs between the compressed refrigerant and water; an expansion valve configured to expand the refrigerant condensed in the refrigerant-water heat exchanger; an outdoor heat exchanger in which heat exchange occurs between the refrigerant expanded in the expansion valve and outdoor air; an outdoor fan disposed adjacent to the outdoor heat exchanger; and a controller configured to turn off the compressor and the outdoor fan based on an abnormal state of the refrigerant-water heat exchanger, and turn on the compressor in a turned-off state of the outdoor fan.

Description

Technical Field

[0001] The present disclosure relates to a heat pump system and a control method thereof, and more particularly to a heat pump type system capable of supplying hot water through heat exchange and a control method thereof. Background Art

[0002] Generally speaking, heat will naturally move from the hotter side to the colder side, but in order to move heat from the colder side to the hotter side, some external force must be applied. This is the principle of heat pumps. Heat pumps perform cooling and heating (air to air) and water supply (air to water) by utilizing the heat generated and recovered by the cycle of compression, condensation and evaporation of refrigerant.

[0003] A multi-type air heating and cooling device using a heat pump method (hereinafter referred to as an "air conditioning system") includes an outdoor unit, an indoor unit, and a hydronic unit, and uses heat from a heat pump to heat an indoor floor or cool or heat indoor air.

[0004] In a heat pump system of a conventional air conditioner, during a heating operation, an outdoor unit exchanges heat with air through an evaporator, and the temperature of indoor air is adjusted to a temperature required by a user through a condenser of the indoor unit.

[0005] Energy-saving heating / cooling solution (EHS) systems are the same in that the outdoor unit exchanges heat with the air, but it exchanges heat between the refrigerant and water through a heat exchanger in the indoor unit or outdoor unit to provide water at a water temperature that meets user needs.

[0006] Based on heating operation, the EHS system is divided into a single system having both an evaporator and a condenser in the outdoor unit and a split system having an evaporator in the outdoor unit and a condenser on the indoor side, and the supplied water is used for floor heating, radiator, water heating, fan coil, etc.

[0007] During the process of exchanging heat with the refrigerant to produce cold or hot water, the water temperature can drop below freezing, causing the heat exchanger to freeze and become damaged.

[0008] Typically, to prevent such heat exchangers from freezing, antifreeze or antifreeze valves are applied, or temperature sensors are embedded to detect freezing. Summary of the invention Technical issues

[0009] Embodiments of the present disclosure provide a heat pump system and a control method thereof, wherein, when a heat exchanger operates abnormally (for example, when it is detected that the heat exchanger is at risk of freezing, for example due to a failure of a diverter valve), the heat exchanger can be made to operate normally by controlling an outdoor fan and an expansion valve to allow the diverter valve to operate normally when the system is restarted after a shutdown. Technical Solution

[0010] According to an exemplary embodiment of the present disclosure, a heat pump system includes: a compressor configured to compress a refrigerant; a refrigerant-water heat exchanger, in which heat exchange occurs between the compressed refrigerant and water; an expansion valve, configured to expand the refrigerant condensed in the refrigerant-water heat exchanger; an outdoor heat exchanger, in which heat exchange occurs between the refrigerant expanded in the expansion valve and outdoor air; an outdoor fan, the outdoor fan is disposed adjacent to the outdoor heat exchanger; and a condensing temperature sensor, the condensing temperature sensor being configured to detect the refrigerant condensed in the refrigerant-water heat exchanger. a water inlet temperature sensor configured to detect the temperature of water entering the refrigerant-water heat exchanger; a water outlet temperature sensor configured to detect the temperature of water undergoing heat exchange in the refrigerant-water heat exchanger; and a controller configured to: determine whether the refrigerant-water heat exchanger is in an abnormal state based on the detection results of the condensing temperature sensor, the water inlet temperature sensor and the water outlet temperature sensor, and based on the abnormal state of the refrigerant-water heat exchanger, turn off the compressor and the outdoor fan, and turn on the compressor when the outdoor fan is in the off state.

[0011] The controller may determine that the refrigerant-water heat exchanger is operating normally in response to the detected temperature of the condensed refrigerant being higher than the inlet water temperature and the detected outlet water temperature being higher than the detected inlet water temperature.

[0012] The controller may control the opening degree of the expansion valve to be equal to or greater than the first opening degree based on an abnormal state of the refrigerant-water heat exchanger.

[0013] The controller may determine whether the refrigerant-water heat exchanger is in an abnormal state based on detection results of a condensing temperature sensor, a water inlet temperature sensor, and a water outlet temperature sensor after controlling the compressor, the outdoor fan, and the expansion valve.

[0014] The controller may determine whether a temperature detected by the condensing temperature sensor exceeds a predetermined temperature in response to the refrigerant-water heat exchanger being in an abnormal state.

[0015] The controller may control the outdoor fan to rotate at a speed equal to or greater than a reference speed and control the expansion valve to open at a second opening degree or greater when determining that the temperature detected by the condensing temperature sensor exceeds a predetermined temperature.

[0016] The controller may turn off the compressor and the outdoor fan in response to a predetermined time elapsed after controlling the outdoor fan to rotate at a speed equal to or greater than a reference speed and controlling the expansion valve to open at a second opening degree or more.

[0017] The heat pump system may further include a high pressure sensor for detecting the high pressure of the refrigerant compressed in the compressor, wherein the controller may determine whether the high pressure detected by the high pressure sensor exceeds a predetermined pressure in response to the refrigerant-water heat exchanger being in an abnormal state.

[0018] The controller may control the outdoor fan to rotate at a speed equal to or greater than a reference speed and control the expansion valve to open at a second opening degree or greater when determining that the pressure detected by the high pressure sensor exceeds a predetermined pressure.

[0019] The controller may turn off the compressor and the outdoor fan in response to a predetermined time elapsed after controlling the outdoor fan to rotate at a speed equal to or greater than a reference speed and controlling the expansion valve to open at a second opening degree or more.

[0020] According to an exemplary embodiment of the present disclosure, a method for controlling a heat pump system is provided, the method comprising detecting a temperature of a refrigerant condensed in a refrigerant-water heat exchanger, detecting a temperature of water entering the refrigerant-water heat exchanger, detecting a temperature of water undergoing heat exchange in the refrigerant-water heat exchanger, determining whether the refrigerant-water heat exchanger is in an abnormal state based on detection results of a plurality of temperatures, in response to determining that the refrigerant-water heat exchanger is in an abnormal state, turning off a compressor and an outdoor fan, and turning on the compressor when the outdoor fan is in an off state.

[0021] Determining whether the refrigerant-water heat exchanger is in an abnormal state may include: in response to the detected temperature of the condensed refrigerant being higher than the temperature of water entering the heat exchanger, and the detected temperature of water that has undergone heat exchange being higher than the detected temperature of water entering the heat exchanger, determining that the refrigerant-water heat exchanger is operating normally.

[0022] The method may further include controlling an opening degree of the expansion valve to be equal to or greater than a first opening degree based on the refrigerant-water heat exchanger being in an abnormal state.

[0023] The method may further include determining whether the refrigerant-water heat exchanger is in an abnormal state based on detection results of the plurality of temperatures after controlling the compressor, the outdoor fan, and the expansion valve.

[0024] The method may further include determining whether a temperature detected by a condensing temperature sensor exceeds a predetermined temperature in response to the refrigerant-water heat exchanger being in an abnormal state.

[0025] The method may further include, when it is determined that the detected temperature of the condensed refrigerant exceeds a predetermined temperature, controlling the outdoor fan to rotate at a speed equal to or greater than a reference speed, and controlling the expansion valve to open at a second opening degree or greater.

[0026] The method may further include turning off the compressor and the outdoor fan in response to a predetermined time lapse after controlling the outdoor fan to rotate at a speed equal to or greater than a reference speed and controlling the expansion valve to open at a second opening degree or more.

[0027] The method may further include detecting a high pressure of the refrigerant compressed in the compressor, and determining whether the detected high pressure of the refrigerant exceeds a predetermined pressure in response to the refrigerant-water heat exchanger being in an abnormal state.

[0028] The method may further include controlling the outdoor fan to rotate at a speed equal to or greater than a reference speed and controlling the expansion valve to open at a second opening degree or greater when it is determined that the detected high pressure of the refrigerant exceeds a predetermined pressure.

[0029] The method may further include turning off the compressor and the outdoor fan in response to a predetermined time lapse after controlling the outdoor fan to rotate at a speed equal to or greater than a reference speed and controlling the expansion valve to open at a second opening degree or more. Beneficial Effects

[0030] According to various embodiments of the present disclosure, when a heat exchanger operates abnormally (for example, when it is detected that the heat exchanger is at risk of freezing, for example due to a failure of a diverter valve), the heat exchanger can be made to operate normally by controlling the outdoor fan and the expansion valve to allow the diverter valve to operate normally when it is restarted after a system shutdown. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a block diagram showing a heat pump system according to an embodiment.

[0032] Figure 2 is a schematic diagram illustrating the flow of refrigerant during a heating operation of a heat pump system according to an embodiment.

[0033] Figure 3 is a schematic diagram illustrating the flow of refrigerant during a cooling operation of a heat pump system according to an embodiment.

[0034] Figure 4 is a schematic diagram showing the structure of a diverter valve.

[0035] Figure 5 is a control block diagram of a heat pump system according to an embodiment.

[0036] Figure 6 is a schematic diagram showing a plurality of sensors included in a heat pump system according to an embodiment.

[0037] Figure 7is a flowchart illustrating detecting an abnormal state of a refrigerant-water heat exchanger and controlling a heat pump system based on the detected abnormal state according to an embodiment.

[0038] Figure 8 It shows that Figure 7 Flow chart for re-determining whether the refrigerant-water heat exchanger is operating normally after control.

[0039] Fig. 9 is a control block diagram showing a heat pump system according to an embodiment.

[0040] Fig.10 is a flow chart illustrating a method of controlling a heat pump system based on a condensing temperature to protect the heat pump system according to an embodiment.

[0041] Fig.11 is a control block diagram showing a heat pump system according to another embodiment.

[0042] Fig.12 is a flow chart illustrating a method for controlling a heat pump system based on high pressure to protect the heat pump system according to another embodiment. DETAILED DESCRIPTION

[0043] The embodiments described in the present disclosure and the configurations shown in the drawings are merely examples of various exemplary embodiments of the present disclosure, which may be used in various different ways at the time of filing this application.

[0044] Furthermore, the same reference numerals or symbols shown in the drawings of the present disclosure represent similar elements or components that perform substantially the same functions.

[0045] The terms used herein are only for describing the embodiments and are not intended to limit and / or constrain the present disclosure. Unless otherwise clearly indicated in the context, the singular forms of "a", "an" and "the" also include plural forms. In the present disclosure, the terms "including", "having" and the like are used to specify features, graphics, steps, operations, elements, components or combinations thereof, but do not exclude the presence or addition of one or more features, graphics, steps, operations, elements, components or combinations thereof.

[0046] When a given element is referred to as being “connected to,” “coupled to,” “supported by,” or “in contact with” another element, it should be understood that the element may be directly or indirectly connected to, coupled to, supported by, or in contact with the other element.

[0047] It should be understood that although the terms "first", "second", "primary", "secondary", etc. used herein can be used to describe various elements, the elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element can be referred to as a second element, and a second element can be referred to as a first element without departing from the scope of the present disclosure. The term "and / or" includes multiple combinations of related items or any one item in multiple related items.

[0048] Hereinafter, various embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0049] Figure 1 A block diagram of a heat pump system according to an embodiment is shown.

[0050] The heat pump system 1 may include a compressor 102 , a refrigerant-water heat exchanger 112 , an expansion valve 110 , an outdoor heat exchanger 108 , a diverter valve 106 , and a collector 104 .

[0051] The compressor 102 may compress the low-temperature, low-pressure refrigerant sucked through the inlet side 102a to form a high-temperature, high-pressure refrigerant, and then discharge the high-temperature, high-pressure refrigerant through the outlet side 102b. The compressor 102 may be configured as a variable frequency compressor whose compression capacity varies according to an input frequency, or may be configured as a combination of a plurality of constant speed compressors whose compression capacity is constant. The inlet side 102a of the compressor 102 may be connected to the collector 104, and the outlet side 102b of the compressor 102 may be connected to the diverter valve 106. The diverter valve 106 may also be connected to the collector 104.

[0052] The accumulator 104 may be installed between the inlet side 102a of the compressor 102 and the diverter valve 106. The accumulator 104 may temporarily store a mixture of oil and refrigerant in response to the condensed liquid refrigerant flowing in through the diverter valve 106, and may prevent damage to the compressor 102 by separating the non-evaporated liquid refrigerant and preventing the liquid refrigerant from being sucked into the compressor 102. The gaseous refrigerant separated from the accumulator 104 may be sucked into the inlet side 102a of the compressor 102.

[0053] The flow divider valve 106 may be configured as a four-way valve, which can divide the refrigerant flow discharged from the compressor 102 according to the operation mode (cooling or heating), thereby forming a refrigerant flow path required for the corresponding mode operation. The flow divider valve 106 may have a first port 106a connected to the outlet side 102b of the compressor 102, a second port 106b connected to the outdoor heat exchanger 108 side, a third port 106c connected to the refrigerant-water heat exchanger 112 side, and a fourth port 106d connected to the collector 104 as the inlet side 102a of the compressor 102.

[0054] The outdoor heat exchanger 108 may operate as a condenser in a cooling mode and as an evaporator in a heating mode. A first expansion valve 110 may be connected to one side of the outdoor heat exchanger 108. An outdoor fan 109 may be installed in the outdoor heat exchanger 108 to improve the heat exchange efficiency between the refrigerant and the outdoor air.

[0055] The expansion valve 110 may be configured as an electronic expansion valve, which can expand the refrigerant, adjust the flow rate of the refrigerant, and block the flow of the refrigerant when necessary. The expansion valve 110 may also be replaced by any other expansion device that performs these functions.

[0056] In the hot water supply heat exchanger 112, a plurality of heat exchange plates through which the refrigerant passes and a plurality of heat exchange plates through which the water passes may be alternately installed, and cold / hot water may be generated through heat exchange between the heat exchange plates through which the refrigerant passes and the heat exchange plates through which the water passes. The refrigerant compressed by the compressor 102 may be delivered to the refrigerant-water heat exchanger 112. The cold / hot water generated by the refrigerant-water heat exchanger 112 may be supplied to a water tank, a fan coil unit, a floor cooling / heating device, etc., so that it may be used for cold / hot water supply and cooling / heating.

[0057] Figure 2 is a schematic diagram illustrating the flow of refrigerant during a heating operation of a heat pump system according to an embodiment.

[0058] The controller 10 may operate the diverter valve 106 to form a refrigerant flow path in which the first port 106 a and the third port 106 c are connected, and the second port 106 b and the fourth port 106 d are connected.

[0059] Therefore, the refrigerant discharged from the compressor 102 may flow to the refrigerant-water heat exchanger 112 through the diverter valve 106 .

[0060] The refrigerant entering the refrigerant-water heat exchanger 112 may flow to the outdoor heat exchanger 108 through the hot water supply heat exchanger 112. The refrigerant passing through the outdoor heat exchanger 108 may be drawn back into the compressor 102 through the diverter valve 106.

[0061] Therefore, the heat pump system 1 can perform a heating operation by configuring a refrigerant cycle that circulates in the order of compressor 102 →diverter valve 106 →hot water supply heat exchanger 112 →expansion valve 110 →outdoor heat exchanger 108 →diverter valve 106 →collector 104 →compressor 102 .

[0062] The heat pump system 1 of the present disclosure may further include a subcooling heat exchanger 114 .

[0063] The subcooling heat exchanger 114 may be located between the refrigerant-water heat exchanger 112 and the expansion valve 110 to allow the refrigerant to flow to the compressor 102 .

[0064] In other words, in this case, the compressor 102 may perform two-stage refrigerant compression.

[0065] The compressor 102 may include a first compression unit and a second compression unit. The refrigerant passing through the refrigerant-water heat exchanger 112 is introduced into the first compression unit and compressed therein, and the refrigerant passing through the first compression unit and the refrigerant branched and injected from the subcooling heat exchanger 114 located between the refrigerant-water heat exchanger 112 and the expansion valve 110 are introduced into the second compression unit and compressed therein.

[0066] In other words, refrigerant may be injected from the subcooling heat exchanger 114 into the compressor 102 by extracting refrigerant passing through the refrigerant-water heat exchanger 112 and injecting only vapor refrigerant into an injection port of the compressor 102 .

[0067] Therefore, the compressor 102 may compress the refrigerant branched and injected from the subcooling heat exchanger 114 in addition to the refrigerant passing through the refrigerant-water heat exchanger 112 in the conventional cycle.

[0068] Therefore, the efficiency of the compressor 102 can be improved by supplying the vapor refrigerant to the injection port of the compressor 102, and the capacity of the condenser can be increased by increasing the flow rate of the refrigerant on the condenser side. In addition, by further ensuring the subcooling level of the refrigerant on the discharge side in the refrigerant-water heat exchanger 112 (internal heat exchanger), efficient operation can be performed.

[0069] Figure 3 is a schematic diagram showing the flow of refrigerant during cooling operation of a heat pump system according to an embodiment.

[0070] The controller 10 may operate the diverter valve 106 to form a refrigerant flow path in which the first port 106 a and the second port 106 b are connected, and the third port 106 c and the fourth port 106 d are connected.

[0071] Therefore, the refrigerant discharged from the compressor 102 may flow to the indoor unit through the diverter valve 106 and the outdoor heat exchanger 108. In this case, the outdoor heat exchanger 108 may function as a condenser.

[0072] The refrigerant entering the indoor unit may pass through the refrigerant-water heat exchanger 112 , and the refrigerant passing through the refrigerant-water heat exchanger 112 may be introduced back to the compressor 102 via the diverter valve 106 .

[0073] Therefore, the heat pump system 1 can perform a cooling operation by configuring a refrigerant cycle that circulates in the order of compressor 102 →diverter valve 106 →outdoor heat exchanger 108 →hot water supply heat exchanger 112 →diverter valve 106 →collector 104 →compressor 102 .

[0074] The basic configuration of the heat pump system 1 and the flow of the refrigerant are described above.

[0075] Figure 4 is a schematic diagram showing the structure of a diverter valve.

[0076] As described above, the heating operation and the cooling operation of the heat pump system 1 may be controlled according to the operation of the diverter valve 106 .

[0077] More specifically, by inputting an electrical signal to the pilot valve 107 in the diverter valve 106 , the pilot valve 107 can apply pressure to a slider in the diverter valve 106 to control the position of the slider, thereby switching the flow path.

[0078] In a case where foreign matter or the like exists in the pilot valve 107 and the pressure applied by the pilot valve 107 is not correctly transmitted to the slider, an error may occur in switching of the flow path.

[0079] In winter or similar seasons, when the outdoor temperature is low, the user may want the heat pump system 1 to perform a heating operation to increase the indoor temperature. Therefore, a refrigerant flow path for the heating operation must be formed without transmitting pressure. Therefore, a refrigerant flow path in which the first port 106a and the second port 106b are connected and the third port 106c and the fourth port 106d are connected may be formed in the diverter valve 106.

[0080] In this case, the temperature of the water passing through the refrigerant-water heat exchanger 112 may drop below the freezing point, causing the water to freeze. The freezing of the water may cause the refrigerant-water heat exchanger 112 to freeze.

[0081] Therefore, it is necessary to remove foreign matter in the pilot valve 107 to ensure the normal operation of the diverter valve 106 .

[0082] Hereinafter, a process of controlling the configuration within the heat pump system 1 to resolve the abnormal state of the refrigerant-water heat exchanger 112 due to the abnormal operation of the refrigerant-water heat exchanger 106 will be described in detail.

[0083] Figure 5 is a control block diagram of a heat pump system according to an embodiment, Figure 6 is a schematic diagram showing a plurality of sensors included in a heat pump system according to an embodiment.

[0084] also, Figure 7is a flow chart showing a method of detecting an abnormal state of a refrigerant-water heat exchanger and controlling a heat pump system based on the detected abnormal state, Figure 8 It shows that Figure 7 Flow chart for re-determining whether the refrigerant-water heat exchanger is operating normally after control.

[0085] The heat pump system 1 may include a compressor 102, a refrigerant-water heat exchanger 112, an outdoor heat exchanger 108, an outdoor fan 109, an expansion valve 110, and a controller 10. The controller 10 may include a processor 11 and a memory 12.

[0086] The heat pump system 1 may further include a condensing temperature sensor 120, a water outlet temperature sensor 122, and a water inlet temperature sensor 126. The condensing temperature sensor 120 may detect the temperature of the condensed refrigerant when it exchanges heat with water during the process of passing through the refrigerant-water heat exchanger 112.

[0087] The water outlet temperature sensor 122 can detect the temperature of the water when exchanging heat with the refrigerant during the process of passing through the refrigerant-water heat exchanger 112 .

[0088] The water inlet temperature sensor 126 may detect the temperature of water flowing into the refrigerant-water heat exchanger 112 before exchanging heat with the refrigerant in the refrigerant-water heat exchanger 112 .

[0089] Various information detected by the plurality of sensors may be used in the control process of the controller 10 described below, which will be described in detail below.

[0090] The compressor 102 may compress the refrigerant, and the refrigerant-water heat exchanger may perform heat exchange between the compressed refrigerant and the incoming water. The expansion valve 110 may expand the condensed refrigerant when passing through the refrigerant-water heat exchanger 112 .

[0091] The outdoor heat exchanger 108 may perform heat exchange between the refrigerant expanded in the expansion valve and the outdoor air, and the outdoor heat exchanger 108 may be provided with an outdoor fan 109 to improve the heat exchange efficiency between the refrigerant and the outdoor air.

[0092] The controller 10 may include a memory 12 for storing a control program and control data for controlling the expansion valve 110, the outdoor fan 109, and the compressor 102, and a processor 11 for generating a control signal according to the control program and control data stored in the memory 12. The memory 12 and the processor 11 may be formed integrally or separately.

[0093] The memory 12 may store temperatures and pressures detected by various sensors, and may store programs and data for controlling the expansion valve 110 , the outdoor fan 109 , and the compressor 102 .

[0094] The memory 12 may include a volatile memory, such as a static random access memory (S-RAM), a dynamic random access memory (DRAM), etc., for temporarily storing data. The memory 12 may also include a non-volatile memory, such as a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), etc., for storing data for a long time.

[0095] The processor 11 may include various logic circuits and operation circuits, and may process data according to a program provided by the memory 12 and generate a control signal according to the processing result.

[0096] Reference Figure 7 , the controller 10 may determine whether the refrigerant-water heat exchanger is in an abnormal state based on the detection results of the condensing temperature sensor, the water inlet temperature sensor, and the water outlet temperature sensor ( 701 ).

[0097] As described above, in the case where foreign matter or the like is present in the pilot valve 107 to prevent normal flow path switching of the diverter valve 106, for example, in winter when the outdoor temperature is low, the flow path for the heating operation may not be properly formed.

[0098] In this case, the controller 10 may determine whether the refrigerant-water heat exchanger 112 operates normally by comparing the temperature of water heat-exchanging with the refrigerant-water heat exchanger 112 .

[0099] More specifically, the controller 10 can determine that the refrigerant-water heat exchanger 112 is operating normally in response to the condensed refrigerant temperature detected by the condensing temperature sensor 120 being higher than the inlet water temperature detected by the inlet water temperature sensor (yes in 703), and the outlet water temperature detected by the outlet water temperature sensor being higher than the inlet water temperature detected by the inlet water temperature sensor (yes in 705).

[0100] In other words, the controller 10 can determine that the refrigerant-water heat exchanger 112 is operating abnormally in response to the condensed refrigerant temperature detected by the condensing temperature sensor 120 being lower than the inlet water temperature detected by the inlet water temperature sensor (No in 703), or the outlet water temperature detected by the outlet water temperature sensor being lower than the inlet water temperature detected by the inlet water temperature sensor (No in 705).

[0101] The controller 10 may turn off the compressor and the outdoor fan based on the abnormal state of the refrigerant-water heat exchanger 112 ( 707 ).

[0102] In other words, the controller 10 may shut down the compressor 102 and the outdoor fan 109 to protect the heat pump system when determining that the refrigerant-water heat exchanger 112 is in an abnormal state, for example, when a freezing risk of the refrigerant-water heat exchanger 112 is detected as described above.

[0103] Thereafter, when the heat pump system 1 is restarted, only the compressor 102 may be turned on, while the outdoor fan 109 is in the off state ( 709 ).

[0104] In response to turning on only the compressor 102 when the outdoor fan 109 is stopped, as the temperature increases, the amount of air discharged to the outside of the outdoor heat exchanger 108 may decrease and the internal high pressure may increase.

[0105] Increased temperature and internal high pressure may cause the viscosity of foreign matter generated in the pilot valve 107 within the diverter valve 106 to weaken, and when pressure is applied, the foreign matter in the pilot valve 107 may be removed.

[0106] Removing the foreign matter in the pilot valve 107 allows pressure to be normally applied to the slider in the diverter valve 106 , thereby changing the existing cooling operation flow path to a heating operation flow path.

[0107] In other words, the state in which the first port 106a and the second port 106b are connected and the third port 106c and the fourth port 106d are connected may be changed to the state in which the first port 106a and the third port 106c are connected and the second port 106b and the fourth port 106d are connected, thereby forming a heating operation refrigerant path.

[0108] The controller 10 may control the opening degree of the expansion valve 110 to be equal to or greater than the first opening degree based on the abnormal state of the refrigerant-water heat exchanger 112 ( 711 ).

[0109] In this case, the first opening degree may refer to an opening degree of 20% based on the maximum opening degree of the expansion valve 110. However, the present disclosure is not limited thereto, and an appropriate ratio may be set to solve the abnormal state of the refrigerant-water heat exchanger 112.

[0110] By controlling the opening degree of the expansion valve 110 to be equal to or greater than the first opening degree, the internal high pressure can be increased.

[0111] As described above, as the temperature and the internal high pressure increase, the viscosity of the foreign matter generated in the pilot valve 107 within the diverter valve 106 may be weakened, and thus the foreign matter in the pilot valve 107 may be removed by applying pressure.

[0112] When the foreign matter in the pilot valve 107 is removed and pressure is normally applied to the slider in the diverter valve 106 , the existing cooling operation flow path can be changed to the heating operation flow path.

[0113] The controller 10 may then determine whether the refrigerant-water heat exchanger 112 is operating normally, and control the expansion valve 110, the outdoor fan 109, and the compressor 102 based on the determination result.

[0114] Reference Figure 8 , the controller 10 can re-determine whether the refrigerant-water heat exchanger 112 is in an abnormal state based on the detection results (801) of the condensing temperature sensor 120, the water inlet temperature sensor and the water outlet temperature sensor after controlling the compressor 102, the outdoor fan 109 and the expansion valve 110.

[0115] More specifically, the controller 10 can determine that the refrigerant-water heat exchanger 112 is operating normally (807) in response to the condensed refrigerant temperature detected by the condensing temperature sensor 120 being higher than the inlet water temperature detected by the inlet water temperature sensor (Yes in 803), and the outlet water temperature detected by the outlet water temperature sensor being higher than the inlet water temperature detected by the inlet water temperature sensor (Yes in 805).

[0116] In this case, when comparing and determining the detected temperature, factors such as the deviation between the actual temperature and the detected temperature may result in inaccurate results. Therefore, the controller 10 may determine that the refrigerant-water heat exchanger 112 is operating normally in response to the condensed refrigerant temperature detected by the condensing temperature sensor 120 being higher than a value obtained by subtracting a first constant from the inlet water temperature detected by the inlet water temperature sensor, and the outlet water temperature detected by the outlet water temperature sensor being higher than a value obtained by subtracting a second constant from the inlet water temperature detected by the inlet water temperature sensor.

[0117] In this case, the first constant and the second constant may be constants determined based on the actual temperature and the deviation between the detected temperature and the optimal condensing temperature.

[0118] The controller 10 can determine that the refrigerant-water heat exchanger 112 is operating abnormally and perform the following control in response to the condensed refrigerant temperature detected by the condensing temperature sensor 120 being lower than the inlet water temperature detected by the inlet water temperature sensor (No in 805), or the outlet water temperature detected by the outlet water temperature sensor being lower than the inlet water temperature detected by the inlet water temperature sensor (No in 807).

[0119] Fig. 9 is a control block diagram showing a heat pump system according to an embodiment, Fig.10 is a flow chart illustrating a method of controlling a heat pump system based on a condensing temperature to protect the heat pump system according to an embodiment.

[0120] As described above, when it is determined that the refrigerant-water heat exchanger 112 is in an abnormal state even after the controller 10 controls the outdoor fan 109 and the expansion valve 110 , the operation of the heat pump system 1 may need to be stopped.

[0121] In this case, when the internal high pressure is too high due to the stop of the outdoor fan 109 and the low opening control of the expansion valve 110, the heat pump system 1 may be damaged, so it is necessary to reduce the pressure in response to detecting that the internal high pressure is high.

[0122] Therefore, the controller 10 may determine whether the temperature detected by the condensing temperature sensor 120 exceeds a predetermined temperature.

[0123] The predetermined temperature may be set to an appropriate temperature to protect the heat pump system 1 by preventing damage to the heat pump system 1 and the like.

[0124] The controller 10 may control the outdoor fan 109 to rotate at a speed equal to or greater than a reference speed (1003) and control the expansion valve 110 to have an opening degree equal to or greater than a second opening degree (1005) in response to the temperature detected by the condensing temperature sensor 120 exceeding a predetermined temperature (yes in 1001).

[0125] Here, the reference rotation speed and the second opening degree may be appropriate rotation speed and opening degree values ​​for reducing the high pressure in the heat pump system 1 to protect the heat pump system 1 .

[0126] The outdoor fan 109 may rotate at a speed equal to or greater than a reference speed, and the expansion valve 110 may be opened at a second opening degree or greater to reduce the internal high pressure, thereby protecting the heat pump system 1 .

[0127] The controller 10 may shut down the operation of the compressor 102 and the outdoor fan 109 upon determining that the internal high pressure has been sufficiently reduced.

[0128] The controller 10 may then perform control again to resolve the abnormal state of the refrigerant-water heat exchanger 112 described above.

[0129] Fig.11 is a control block diagram showing a heat pump system according to an embodiment, Fig.12 is a flow chart illustrating a method of controlling a heat pump system based on high pressure to protect the heat pump system according to an embodiment.

[0130] The heat pump system 1 may further include a high pressure sensor 130 that detects the high pressure of the refrigerant compressed in the compressor 102 .

[0131] Fig. 9 and Fig.10The case where the internal high pressure is detected using the condensing temperature sensor 120 because such a high pressure sensor 130 is not separately included has been described, and in this embodiment, the case where the high pressure sensor 130 that can directly detect the high pressure is included will be described.

[0132] The controller 10 may determine whether the high pressure detected by the high pressure sensor 130 exceeds a predetermined pressure in response to the refrigerant-water heat exchanger 112 being in an abnormal state.

[0133] In this case, the predetermined pressure may be set to an appropriate pressure to protect the heat pump system 1 by preventing damage to the heat pump system 1 and the like.

[0134] When the controller 10 determines that the high pressure detected by the high pressure sensor 130 exceeds the predetermined pressure (yes in 1201), it can control the outdoor fan 109 to rotate at a speed equal to or greater than the reference speed (1203), and control the expansion valve 110 to open at a second opening degree or greater (1205).

[0135] By rotating the outdoor fan 109 at a rotation speed equal to or greater than a reference rotation speed and placing the expansion valve 110 at a second opening degree or greater, the internal high pressure can be reduced, thereby protecting the heat pump system 1 .

[0136] Thereafter, upon determining that the internal high pressure has been sufficiently reduced, the controller 10 may shut down the operations of the compressor 102 and the outdoor fan 109 .

[0137] Thereafter, the controller 10 may perform control again to resolve the abnormal state of the refrigerant-water heat exchanger 112 described above.

[0138] According to the above-mentioned heat pump system and control method thereof, when the heat exchanger operates abnormally (for example, when it is detected that the heat exchanger is at risk of freezing due to a diverter valve failure, for example), the heat exchanger can be made to operate normally by controlling the outdoor fan and the expansion valve to allow the diverter valve to operate normally when the system is restarted after shutdown.

[0139] At the same time, the embodiments of the present disclosure can be implemented in the form of a recording medium storing executable instructions of a computer. The instructions can be stored in the form of program code, and when executed by a processor, a program module for performing the operations of the embodiments of the present disclosure can be generated. The recording medium can be implemented as a computer-readable storage medium.

[0140] Computer-readable storage media include all types of storage media that store instructions that can be decoded by a computer. These storage media may include, for example, read-only memory (ROM), random access memory (RAM), magnetic tapes, magnetic disks, flash memory, optical data storage devices, etc.

[0141] As described above, the embodiments of the present disclosure have been described with reference to the accompanying drawings. Those skilled in the art will understand that the present disclosure can be implemented in forms other than the embodiments of the present disclosure without changing the technical ideas or basic features of the present disclosure. The embodiments of the present disclosure are exemplary and should not be construed as limiting.

Claims

1. A heat pump system, comprising: a compressor configured to compress a refrigerant; a refrigerant-water heat exchanger in which heat exchange occurs between the compressed refrigerant and water; an expansion valve configured to expand the refrigerant condensed in the refrigerant-water heat exchanger; an outdoor heat exchanger in which heat exchange occurs between the refrigerant expanded in the expansion valve and outdoor air; an outdoor fan, the outdoor fan being disposed adjacent to the outdoor heat exchanger; a condensing temperature sensor configured to detect a temperature of the refrigerant condensed in the refrigerant-water heat exchanger; an inlet water temperature sensor configured to detect the temperature of water entering the refrigerant-water heat exchanger; an outlet water temperature sensor configured to detect the temperature of water undergoing heat exchange in the refrigerant-water heat exchanger; as well as The controller is configured as: determining whether the refrigerant-water heat exchanger is in an abnormal state based on the detection results of the condensing temperature sensor, the water inlet temperature sensor and the water outlet temperature sensor, and Based on an abnormal state of the refrigerant-water heat exchanger, the compressor and the outdoor fan are turned off, and the compressor is turned on in a turned-off state of the outdoor fan.

2. The heat pump system according to claim 1, wherein: The controller determines that the refrigerant-water heat exchanger is operating normally in response to the detected temperature of the condensed refrigerant being higher than the inlet water temperature and the detected outlet water temperature being higher than the detected inlet water temperature.

3. The heat pump system according to claim 2, wherein: The controller controls the opening degree of the expansion valve to be equal to or greater than a first opening degree based on an abnormal state of the refrigerant-water heat exchanger.

4. The heat pump system according to claim 3, wherein: The controller determines whether the refrigerant-water heat exchanger is in an abnormal state based on detection results of the condensing temperature sensor, the water inlet temperature sensor, and the water outlet temperature sensor after controlling the compressor, the outdoor fan, and the expansion valve.

5. The heat pump system according to claim 4, wherein: The controller determines whether a temperature detected by the condensing temperature sensor exceeds a predetermined temperature in response to the refrigerant-water heat exchanger being in an abnormal state.

6. The heat pump system according to claim 5, wherein: When the controller determines that the temperature detected by the condensing temperature sensor exceeds the predetermined temperature, The outdoor fan is controlled to rotate at a rotation speed equal to or greater than a reference rotation speed, and the expansion valve is controlled to open at a second opening degree or greater.

7. The heat pump system according to claim 6, wherein: The controller turns off the compressor and the outdoor fan in response to a predetermined time elapsed after controlling the outdoor fan to rotate at a speed equal to or greater than the reference speed and controlling the expansion valve to open at the second opening degree or more.

8. The heat pump system according to claim 4, further comprising a high pressure sensor for detecting a high pressure of the refrigerant compressed in the compressor, in, The controller determines whether the high pressure detected by the high pressure sensor exceeds a predetermined pressure in response to the refrigerant-water heat exchanger being in an abnormal state.

9. The heat pump system according to claim 8, wherein: When the controller determines that the pressure detected by the high pressure sensor exceeds the predetermined pressure, The outdoor fan is controlled to rotate at a rotation speed equal to or greater than a reference rotation speed, and the expansion valve is controlled to open at a second opening degree or greater.

10. The heat pump system according to claim 9, wherein: The controller turns off the compressor and the outdoor fan in response to a predetermined time elapsed after controlling the outdoor fan to rotate at the speed equal to or greater than the reference speed and controlling the expansion valve to open at the second opening degree or greater.

11. A method for controlling a heat pump system, comprising: detecting the temperature of the refrigerant condensed in the refrigerant-water heat exchanger; detecting the temperature of water entering the refrigerant-water heat exchanger; detecting the temperature of water undergoing heat exchange in the refrigerant-water heat exchanger; Based on the detection results of the multiple temperatures, determining whether the refrigerant-water heat exchanger is in an abnormal state; In response to determining that the refrigerant-water heat exchanger is in an abnormal state, shutting down the compressor and the outdoor fan; as well as When the outdoor fan is in an off state, the compressor is turned on.

12. The method according to claim 11, wherein: Determining whether the refrigerant-water heat exchanger is in an abnormal state includes: In response to the detected temperature of the condensed refrigerant being higher than the temperature of water entering the heat exchanger and the detected temperature of water having undergone heat exchange being higher than the detected temperature of water entering the heat exchanger, it is determined that the refrigerant-water heat exchanger is operating normally.

13. The method according to claim 12, further comprising: Based on the refrigerant-water heat exchanger being in an abnormal state, the opening degree of the expansion valve is controlled to be equal to or greater than a first opening degree.

14. The method according to claim 13, further comprising: After controlling the compressor, the outdoor fan, and the expansion valve, it is determined whether the refrigerant-water heat exchanger is in an abnormal state based on the detection results of the plurality of temperatures.

15. The method according to claim 14, further comprising: In response to the refrigerant-water heat exchanger being in an abnormal state, it is determined whether a temperature detected by a condensing temperature sensor exceeds a predetermined temperature.

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