Cooling and heating device and defrosting operating procedure therefor

Abstract

Cooling and heating device, which includes: a compressor (21) configured to compress coolant; an external heat exchanger (23) configured to exchange heat between outside air and coolant; an expansion part (24) configured to expand coolant; an internal heat exchanger (31) configured to exchange heat between the internal air or water and the coolant; and a control unit (63) configured to reduce the defrosting operating frequency of the compressor (21) during a defrosting operation based on the temperature of the external heat exchanger (23), wherein the control unit (63) is configured to continuously reduce the defrosting operating frequency of the compressor (21) during a time period between a first time point and a second time point of the defrosting operation, during which the temperature of the external heat exchanger (23) rises to a range of predetermined critical temperatures, and wherein the control unit (63) is configured to keep the de-icing operating frequency of the compressor (21) constant during a time interval between the second time point and a de-icing operating end point.

Description

TECHNICAL AREA

[0001] A cooling and heating device and a de-icing operating method for this purpose are disclosed here. BACKGROUND

[0002] Heat pump-type cooling and heating devices are devices that heat or cool water supplied through a water source as a result of heat exchange between refrigerants and air or water, based on a heat pump cycle. Using the heated or cooled water, heat pump-type cooling and heating devices cool or heat an interior space. They also supply the heated water directly to a user who wishes to use it.

[0003] Fig. Figure 1 is a schematic view showing a configuration of a state-of-the-art heat pump operating in a heat pump cycle. The reference symbols in Fig. 1 are only components in Fig. 1 given. With reference to Fig. 1 comprises a state-of-the-art heat pump, a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, an outdoor fan 14, an indoor heat exchanger 15, an indoor fan 16 and an expansion valve 17.

[0004] The compressor 11 compresses and circulates refrigerant. The four-way valve 12 reverses the flow of refrigerant in either a forward or reverse direction. The external heat exchanger 13 is used as a condenser during a cooling process and as an evaporator during a heating process. The external blower 14 blows air around the external heat exchanger 13 into an outdoor space. The internal heat exchanger 15 is used as an evaporator during a cooling process and as a condenser during a heating process. The internal blower 16 blows air around the internal heat exchanger 15 into an indoor space. The expansion valve 17 is located between the external heat exchanger 13 and the internal heat exchanger 15 and converts the refrigerant into cooling gases with a low temperature and low pressure.

[0005] Operation of the heat pump with the above configuration is described as follows.

[0006] During cooling operation of the heat pump, refrigerant gases discharged from the compressor 11 are introduced through the four-way valve 12 into the outdoor heat exchanger 13 and converted by the expansion valve 17 into a low-temperature, low-pressure refrigerant before being introduced into the indoor heat exchanger. The refrigerant gases, which evaporate in the indoor heat exchanger 15, exchange heat with the indoor air and are drawn back into the compressor 11 through the four-way valve 12 and circulated.

[0007] During heating operation of the heat pump, refrigerant gases discharged from the compressor 11 are introduced through the four-way valve 12 into the internal heat exchanger 15 and condensed to exchange heat with the indoor air. The refrigerant gases that have passed through the internal heat exchanger 15 are then converted into a low-temperature, low-pressure refrigerant by the expansion valve 17 and are evaporated as they pass through the external heat exchanger 13. The evaporated refrigerant gases are drawn through the four-way valve 12 into the compressor 21 and circulated.

[0008] At low outside temperatures, the surface temperature of the outdoor heat exchanger 13, which is used as an evaporator during heating operation, falls below zero. Consequently, moisture contained in the outside air adheres to the cold surface of the outdoor heat exchanger 13, blocking a channel of the outdoor fan 14 and causing a deterioration in the heat exchange efficiency of the outdoor heat exchanger 13, leading to a significant reduction in the heating capacity of the heat pump.

[0009] To solve the problem, the heat pump performs a defrosting operation. The defrosting operation is a function of the heat pump that is carried out to melt frost adhering to the outdoor heat exchanger 13, using the outdoor heat exchanger 13 as a condenser.

[0010] In particular, during a predetermined heating operating period, the heating operation is carried out, followed by the defrosting operation, and after the defrosting operation ends, the heating operation is carried out again. In this case, the defrosting operation is carried out when a temperature detected by a pipe temperature sensor 18, which is attached to the surface of the external heat exchanger 13, is a certain temperature or less.

[0011] During defrosting operation, the indoor fan 16 and the outdoor fan 14 stop, and the heat pump circulates refrigerant in a cooling cycle. Hot refrigerant gases discharged from the compressor 11 are introduced into the outdoor heat exchanger 13 and remove frost adhering to its surface.

[0012] The compressor is driven for defrosting operation using a fixed defrosting operating frequency. In this case, the compressor pressure increases rapidly under certain conditions, and consequently, the compressor current also increases. An air-to-water heat pump (AWHP) has a refrigerant circulation pipe with a smaller surface area than that of an air-to-air heat pump (AAHP). Consequently, the compressor pressure in an AWHP increases more than that of a compressor in an AAHP. As a result, defrosting operation of the compressor in an AWHP is not reliably performed and consumes unnecessary power.

[0013] Prior art includes a hot water circulation system associated with a heat pump and a method for controlling it, as disclosed in Korean patent KR 10 1 329 509 B1 (published on 07 Nov. 2013).

[0014] JP 2009- 92 335 A discloses a variable-speed compressor, a four-way valve, an external heat exchanger, a decompression expansion valve and an internal heat exchanger connected in a ring to form a refrigerant circuit.

[0015] CN 1 07 289 601 B discloses a method comprising the following steps: when a defrosting mode of the air conditioning system is operated, an outside ambient temperature and a coil temperature of an outside heat exchanger are obtained, and a defrosting operating frequency of a compressor of the air conditioning system is dynamically adjusted according to the outside ambient temperature and the coil temperature of the outside heat exchanger.

[0016] CN 1 10 469 993 A discloses a control method and a device for defrosting air conditioners and an air conditioner. The control method comprises the steps of: sensing the refrigerant inlet temperature, the outside coil temperature, and the temperature of the upper casing of an outside heat exchanger while the air conditioner is operating in a heating mode. SUMMARY Technical Problem

[0017] It is an object of the present invention to provide a cooling and heating device and a de-icing operating method thereof that can reliably perform a de-icing operation.

[0018] It is an object of the present invention to provide a cooling and heating device and a defrosting operating method thereof that can avoid unnecessary power consumption.

[0019] It is an object of the present invention to provide a cooling and heating device and a defrosting operating method thereof which can prevent a rapid increase in the current of a compressor without increasing the time it takes to carry out a defrosting operation.

[0020] Aspects according to the present disclosure are not limited to those above, and other aspects and advantages not mentioned above can be clearly understood from the following description and can be understood more clearly from embodiments set forth herein. Technical solution

[0021] The problem is solved by the features of the independent claims. Preferred embodiments are given in the dependent claims.

[0022] In a cooling and heating device and a defrosting operating method thereof in one embodiment, a defrosting operating frequency of a compressor can decrease at a specific time during defrosting operation, thereby preventing a rapid increase in the pressure and current of the compressor.

[0023] In the cooling and heating device and a defrosting operating method thereof in one embodiment, a time for changing a defrosting operating frequency can be determined based on a temperature of an external heat exchanger, and a compressor can be driven with a low defrosting operating frequency from the time of changing a defrosting operating frequency.

[0024] The cooling and heating device in one embodiment may comprise a compressor configured to compress refrigerants, an external heat exchanger configured to exchange heat between outside air and refrigerants, an expansion section configured to expand the refrigerants, an internal heat exchanger configured to exchange heat between inside air or water and the refrigerants, and a control unit configured to control an operating frequency of the compressor depending on an operating mode of the cooling and heating device, wherein the control unit reduces a defrosting operating frequency of the compressor at a first time point of a defrosting operation based on a temperature of the external heat exchanger during the defrosting operation of the cooling and heating device.

[0025] In this case, the control unit can determine the first defrosting operation at a point in time when the temperature of the external heat exchanger reaches a predefined critical temperature. Alternatively, the control unit can determine the first defrosting operation at a point in time when the temperature gradient of the external heat exchanger is positive and the temperature of the external heat exchanger reaches a predefined critical temperature. The critical temperature can be 2 °C or higher.

[0026] The control unit can be configured to set the compressor's defrosting operating frequency to an initial defrosting frequency at the start of the defrosting process, and to change the compressor's defrosting operating frequency from the initial defrosting frequency to a second defrosting frequency at the first point during the defrosting process. The second defrosting operating frequency can be lower than the first defrosting operating frequency.

[0027] The second defrosting operating frequency can be determined based on the capacity of the external heat exchanger. Alternatively, the second defrosting operating frequency can be half the frequency of the first defrosting operating frequency.

[0028] The compressor can be driven at the second defrosting operating frequency from the first point in time of the defrosting operation. Alternatively, the compressor can be driven at the second defrosting operating frequency from a second point in time of the defrosting operation that is after the first point in time of the defrosting operation, and in a time interval between the first point in time of the defrosting operation and the second point in time of the defrosting operation, the compressor can be driven at a defrosting operating frequency that continuously decreases from the first defrosting operating frequency.

[0029] If the temperature of the external heat exchanger is maintained within a specified critical temperature range, the control unit can control the compressor in such a way that the compressor terminates the defrosting operation.

[0030] As a control method of a cooling and heating device in one embodiment, a defrosting operating method of the cooling and heating device with a compressor configured to compress refrigerant, an external heat exchanger configured to exchange heat between outside air and refrigerant, a sensor configured to measure a temperature of the external heat exchanger, an expansion section configured to expand the refrigerant, an internal heat exchanger configured to exchange heat between inside air or water and the refrigerant, and a control unit configured to control an operating frequency of the compressor depending on an operating mode of the cooling and heating device, may include the compressor operating at a first defrosting operating frequency, the sensor measuring a temperature of the external heat exchanger,The control unit determines a time to change the defrosting operating frequency of the compressor based on the measured temperature of the external heat exchanger, and the compressor operates at a defrosting operating frequency lower than the first defrosting operating frequency for a period after the time to change the defrosting operating frequency. Beneficial effect

[0031] According to the present disclosure, a rapid increase in the pressure of a compressor during a de-icing operation can be prevented, thereby ensuring a reliable de-icing operation.

[0032] According to the disclosure, a rapid increase in the compressor's current during defrosting operation can be prevented, thereby ensuring a reduction in power consumption.

[0033] Special effects are described together with the effects described above in the detailed description section. BRIEF DESCRIPTION OF THE DRAWING

[0034] The accompanying drawings form part of the patent description, represent one or more embodiments in the disclosure and, together with the patent description, explain the disclosure; they show: Fig. 1 a schematic view representing a configuration of a state-of-the-art heat pump performing a heat pump cycle operation; Fig. 2 a schematic view showing a configuration of a heat pump geared hot water circulation system in one embodiment; Fig. 3 a perspective view showing a configuration of an indoor unit forming a heat pump geared hot water circulation system; Fig. 4 a conceptual view showing a configuration of a cooling and heating device of the heat pump type, configured to perform a defrosting operation, in one embodiment; Fig. 5 a flowchart showing a defrosting operating procedure of the cooling and heating device of the heat pump type in one embodiment; and Fig. 6 and Fig. 7 Graphs of the operation of a compressor in one embodiment. DETAILED DESCRIPTION

[0035] The aspects, features, and advantages described above are further described below with reference to the accompanying drawings, so that a person skilled in the art in the field to which this disclosure relates can easily implement the technical idea of ​​the disclosure. The disclosure omits a detailed description of known technologies in relation to the disclosure where it is considered that such a description would unnecessarily obscure the core of the disclosure. Preferred embodiments according to the disclosure are described below with particular reference to the accompanying drawings. In the drawings, identical reference numerals may denote identical or similar components.

[0036] When a component is described as "connected," "coupled," or "linked" to another component, it can mean that the component is directly connected, coupled, or linked to that other component. However, it should also be understood that an additional component can be "inserted" between the two components, or that the two components can be "connected," "coupled," or "linked" by an additional component.

[0037] The singular forms "ein", "eine", and "der" used here are intended to include the plural forms as well, unless explicitly stated otherwise. Furthermore, it should be understood that the terms "umfassen" (to include) or "aufweisen" (to exhibit) or similar expressions used here are not necessarily to be interpreted as encompassing all the specified components or steps, but rather as excluding some of the specified components or steps, or as encompassing additional components or steps.

[0038] Below is a cooling and heating device and a de-icing operating method in several embodiments.

[0039] Cooling and heating devices can refer to a device that performs cooling or heating using the heat of vaporization generated when a refrigerant evaporates in an evaporator. Among cooling and heating devices, a heat pump-type cooling and heating device can refer to a device that heats or cools water as a result of heat exchange between refrigerants and air or water, based on a heat pump cycle.

[0040] Furthermore, a heat pump-type hot water recirculation system can refer to a system in which a heat pump-type cooling and heating device and a hot water recirculation unit are coupled to provide heating while supplying hot water. The heat pump-type cooling and heating device can be an air-to-water heat pump (AWHP) system, in which air and water exchange heat.

[0041] For the sake of clarity, the embodiments described in this disclosure are based on the heat pump geared hot water circulation system. However, the embodiments are not limited, and the subject matter of the disclosure can be applied to all types of cooling and heating devices using the heat of vaporization.

[0042] Fig. Figure 2 is a schematic view showing a configuration of a heat pump geared hot water circulation system in one embodiment. Fig. Figure 3 is a perspective view showing a configuration of an indoor unit forming a heat pump geared hot water circulation system.

[0043] With reference to Fig. 2 and Fig. In one embodiment, the heat pump geared hot water circulation system 1 can comprise an outdoor unit 2 implementing a heat pump refrigerant cycle, an indoor unit 3 exchanging heat with a refrigerant undergoing phase transitions according to the heat pump refrigerant cycle to heat water, a hot water supply unit 4 connected to a section of the indoor unit 3 in a heat-exchanging manner and supplying hot water, and a heating unit 5 formed by a water pipe extending from the indoor unit 3. The outdoor unit 2 and the indoor unit 3 can form the heat pump-type cooling and heating device.

[0044] The following describes a configuration of the heat pump geared hot water circulation system 1, which operates in a heating mode.

[0045] The outdoor unit 2 can include a compressor 21, a four-way valve 22, an outdoor heat exchanger 23 and an expansion part 24.

[0046] The compressor 21 can compress refrigerant at high temperature and high pressure. The four-way valve 22 can adjust the direction of flow of refrigerant exiting the compressor 21. During heating operation, the four-way valve 22 can supply refrigerant to a water-coolant heat exchanger 31. The expansion section 24 can expand refrigerant that has passed through the water-coolant heat exchanger 31 to a low temperature and low pressure. The outdoor heat exchanger 23 allows the refrigerant that has passed through the expansion section 24 to exchange heat with the outside air.

[0047] The indoor unit 3 can include a water-coolant heat exchanger 31, a flow switch 32, an expansion tank 33, a water collection tank 34 and a water pump 36.

[0048] The water-coolant heat exchanger 31 allows coolant flowing according to the heat pump refrigerant cycle to exchange heat with water flowing along the water pipe. The water pipe can be installed in such a way that it extends to an outlet side of the water-coolant heat exchanger 31. The coolant stored in the water-coolant heat exchanger 31 can become lukewarm through a hot water supply process or a heating process. The water-coolant heat exchanger 31 can correspond to an internal heat exchanger.

[0049] The flow switch 32 can be mounted on the water pipe and detect a flow of water.

[0050] The expansion tank 33 can buffer a volume of water if the volume of water being heated as it passes through the water-coolant heat exchanger 31 expands to a suitable level or above. The expansion tank 33 can be filled with nitrogen gas.

[0051] The water collection tank 34 can collect water that has passed through the water-coolant heat exchanger 31. An end section of the water pipe can be inserted into the water collection tank 34. The water collection tank 34 can be equipped with an auxiliary heating device 35 and can operate selectively during defrosting or when the heat input through the water-coolant heat exchanger 31 is less than the required heat input. A vent 343 can be provided on the top of the water collection tank 34 to release superheated air from the water collection tank 34. The water collection tank 34 can be equipped with a pressure gauge 341 and a pressure relief valve 342 on either side of it to correctly adjust the pressure in the water collection tank 34.

[0052] The water pump 36 can be located at a specific point on a water pipe on the outlet side of the water collection tank 34. The water pump 36 can pump water that is discharged through the water pipe extending from the outlet side of the water collection tank 34 to supply the water to the hot water supply unit 4 and the heating unit 5.

[0053] A channel diverter valve 71, configured to control the direction of water flow, can be located at a specific point spaced from the water pump 36 in the direction of water flow. The channel diverter valve 71 can be a three-way valve, allowing water pumped by the water pump 36 to flow to the hot water supply unit 4 or the heating unit 5. A hot water supply pipe 48 extending to the hot water supply unit and a heating pipe 53 extending to the heating unit 5 can each connect to the outlet side of the channel diverter valve 71.

[0054] The hot water supply unit 4 can heat water required for work, such as washing a face or dishes, and the like, in order to supply the heated water to a user. The hot water supply unit 4 can include a hot water tank 41, an auxiliary heating device 42, a heat storage unit 43, an auxiliary pump 44, and an auxiliary pipe 47. Additionally, a water inlet 411, through which cold water is introduced, and a water outlet 412, through which heated water is discharged, can be arranged on one side of the hot water supply unit 4. Appliances in a home, such as a shower 45, a humidifier 46, and the like, can connect to the water outlet 412.

[0055] The hot water tank 41 can store water supplied from an external source. The auxiliary heating device 42 and the heat storage unit 43 can be located within the hot water tank 41 and can heat the water stored therein. That is, a section of the hot water supply pipe 48, extending from the channel diverter valve 71, can be inserted into the hot water tank 41 to heat the water stored therein. In some cases, the auxiliary heating device 42 and the heat storage unit 43 can work together to supply additional heat to the water stored in the hot water tank 41.

[0056] An auxiliary pump 44, configured to control a flow velocity in a closed circuit of the auxiliary pipe, and a reversing valve VA for controlling a direction of the flow of water in the auxiliary pipe 47 can be mounted on the auxiliary pipe 47.

[0057] The heating unit 5 can include a floor heating unit 51 and an air heating unit 52.

[0058] The floor heating unit 51 can be configured such that a section of the heating pipe 53 is buried in the floor of an interior space. The floor heating unit 51 can be buried in the floor of an interior space in the form of a meandering line.

[0059] The air heating unit 52 can branch off from a specific point on the heating pipe 53 and be connected in parallel with the floor heating unit 51. The air heating unit 52 can be a fan coil unit, a radiator, or the like. A section of the air heating pipe 54 branching off from the heating pipe 53 can serve as a heat exchange medium for the air heating unit 52.

[0060] Channel diverting valves 55, 56, such as a three-way valve, can be arranged at the point from which the air heating pipe 54 branches off. Consequently, coolants flowing along the heating pipe 53 can flow in such a way that the coolants branch off into the floor heating unit 51 and the air heating unit 52, or only in any direction.

[0061] Furthermore, a first and a second temperature sensor TH1, TH2 can each be mounted on coolant pipes on the inlet and outlet sides of the water-coolant heat exchanger 31, a third and a fourth temperature sensor TH3, TH4 can each be mounted on water pipes on the inlet and outlet sides of the water-coolant pan exchanger 31, a fifth temperature sensor TH5, configured to measure a temperature of water, can be mounted on one side of the water collection tank 34, a sixth temperature sensor TH6, configured to measure a temperature of water, can be mounted on one side of the hot water tank 41, and a seventh temperature sensor TH7, configured to measure a temperature of water, can be mounted on any side of the auxiliary pipe 47.

[0062] The following describes the flow of water in the heat pump geared hot water circulation system 1 as a function of an operating mode.

[0063] In heating mode, water can flow to the heating pipe 53 through the channel diverter valve 71. Consequently, the water can flow along a closed circuit A, which connects the water-coolant heat exchanger 31, the water collection tank 34, the water pump 36, the channel diverter valve 71, and the heating pipe 53. The water flowing along the heating pipe 53 can flow to the air heating unit 52 or to the floor heating unit 51.

[0064] In a hot water supply mode, water can flow through the channel diverter valve 71 to the hot water supply pipe 48. Consequently, the water can flow along a closed circuit B, which connects the water-coolant heat exchanger 31, the water collection tank 34, the water pump 36, the channel diverter valve 71, and the hot water supply pipe 48. During circulation, cold water introduced into the water inlet 411 of the hot water tank 41 can be heated, discharged to the outside through the water outlet 412, and then supplied to the user.

[0065] If the outdoor unit 2 operates for an extended period in a heat pump refrigerant cycle at low outdoor temperatures, frost can form on a surface of the outdoor heat exchanger 23. This frost can significantly reduce the heating efficiency of the heat pump. Consequently, if the temperature of the outdoor heat exchanger 23 drops to a predetermined temperature or below, the heat pump's hot water circulation system 1 can initiate a defrosting cycle.

[0066] The defrosting operation can be performed after the heating operation has ended, and as a result of the completion of the defrosting operation, the next heating operation can be carried out. During the defrosting operation, the actuation of the four-way valve 22 can be reversed to a cooling operation, so that refrigerant circulates in a cooling cycle. In this case, the external heat exchanger 23 can be used as a condenser, and hot refrigerant discharged from the compressor 21 can remove frost adhering to the surface of the external heat exchanger 23.

[0067] The following describes in detail a defrosting operation of the cooling and heating device of the heat pump type with reference to the following drawings.

[0068] Fig. Figure 4 is a conceptual view showing an embodiment of a configuration of a heat pump-type cooling and heating device configured to perform a defrosting operation.

[0069] The cooling and heating device of the heat pump type, which refers to Fig. The subject matter described in section 4 can be a cooling and heating device based on the AWHP described above, but is not limited to this. The subject matter of the disclosure can also be applied to a cooling and heating device based on an air-to-air heat pump (AAHP).

[0070] With reference to Fig. 4 The cooling and heating device of heat pump type can include a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, an expansion part 24, a water-coolant heat exchanger 31, an outdoor fan 61, a temperature sensor 62 and a control unit 63 (Micom, microcomputer).

[0071] The operation of the compressor 21, the four-way valve 22, the external heat exchanger 23, the expansion unit 24, and the water-coolant heat exchanger 31 has been specifically described above. Therefore, a description of these components is omitted here.

[0072] The external blower 61 can be located near the external heat exchanger 23.

[0073] The external blower 61 can blow air around the external heat exchanger 23 to an outside room.

[0074] The temperature sensor 62 can measure the temperature of a pipe that forms the external wall heat exchanger 23.

[0075] A single temperature sensor 62 can be attached to a surface of the pipe of the external heat exchanger 23. The temperature measured by the temperature sensor 62 can be supplied to the control unit 63.

[0076] The control unit 63 can control the operation of components of the heat pump-type cooling and heating device and can be a processor-based device that controls an operating mode of the heat pump-type cooling and heating device. The processor can comprise one or more central processing units (CPUs), application processors, or communication processors.

[0077] In particular, the control unit 63 can set a defrosting operating frequency for the compressor 21 during a defrosting operation and can drive the compressor 21 based on the set defrosting operating frequency. In this case, the defrosting operating frequency of the compressor 21 can be set based on the temperature of the external heat exchanger 23, which is measured by the temperature sensor 62.

[0078] In one embodiment, the control unit 63 can drive the compressor 21 such that the defrosting operating frequency decreases during the defrosting operation of the heat pump-type cooling and heating device. In other words, the control unit 63 can reduce the defrosting operating frequency of the compressor 21 at a first point during the defrosting operation. In this case, the temperature of the outdoor heat exchanger 23, measured by the temperature sensor 62, can be used.

[0079] The following describes the defrosting processes of the cooling and heating device of the heat pump type with reference to Fig. 5 specifically described.

[0080] Fig. Figure 5 is a flowchart showing a defrosting operating procedure for the cooling and heating device of the heat pump type in one embodiment.

[0081] It is assumed that the defrosting operation starts when the temperature of the external heat exchanger 23 drops to a predetermined temperature or less, and that the temperature sensor 62 measures a temperature of the surface of the external heat exchanger 23 in all operating modes of the cooling and heating device of the heat pump type.

[0082] Each step of the de-icing process is described below.

[0083] In step 10 (S10) the four-way valve 22 and the external blower 61 are switched off.

[0084] Step 20 (S20) determines whether the current de-icing operating time is included in a drive maintenance section.

[0085] The drive maintenance phase can refer to a time period in which a specific de-icing operating frequency is temporarily maintained and then increased to ensure the reliability of compressor 21. During the operating hold time phase, the de-icing operating hold frequency of compressor 21 can increase continuously.

[0086] If the current defrosting operating time is included in the operating hold time section, compressor 21 can be driven at the defrosting operating hold frequency in step 30 (S30).

[0087] If the current defrosting operating time is not included in the operating hold time period, compressor 21 can be driven in step 40 (S40) at a first predefined defrosting operating frequency. The first defrosting operating frequency can be 80 Hz.

[0088] In step 50 (S50), the control unit 63 determines whether a temperature of the external heat exchanger 23 meets a condition for ending the defrosting operation.

[0089] The condition for ending the defrosting operation is a predefined condition and is determined depending on whether the temperature of the external heat exchanger 23 is maintained within a range of predefined critical temperatures for a predefined critical time period. The range of critical temperatures can be, for example, 12 to 15 °C and the critical time period can be 20 seconds.

[0090] When the temperature of the external heat exchanger 23 meets the condition to end the defrosting operation, the defrosting operation ends and a heating operation starts in step 60 (S60).

[0091] For example, if the temperature of the external heat exchanger 23 is maintained at 12 to 15 °C for 20 seconds or more, the defrosting operation can end.

[0092] If, on the other hand, the temperature of the external heat exchanger 23 does not meet the condition for ending the defrosting operation, the control unit 63 can determine in step 70 (S70) whether the temperature of the external heat exchanger 23 meets a condition for changing the defrosting operating frequency.

[0093] This means that the compressor 21 can be driven at the first predetermined defrosting operating frequency under the control of the control unit 63, and step 70 (S70) includes determining a first time point for changing the defrosting operating frequency based on the temperature of the external heat exchanger 23.

[0094] The condition for changing the defrosting operating frequency is a predefined condition. In one embodiment, the condition for changing the defrosting operating frequency can be determined depending on whether the current temperature of the external heat exchanger 23 reaches a predetermined critical temperature. That is, the condition for changing the defrosting operating frequency can be defined as the condition for which the current temperature of the external heat exchanger 23 is the predetermined critical temperature or higher.

[0095] In another embodiment, the condition for changing the defrosting operating frequency can be determined depending on whether the current temperature of the external heat exchanger 23 reaches the predetermined critical temperature, while the gradient of the current temperature of the external heat exchanger 23 is a positive gradient. That is, the condition for changing the defrosting operating frequency can be defined as the condition for which the current temperature of the external heat exchanger 23 is the predetermined critical temperature or higher and the gradient of the current temperature of the external heat exchanger 23 is a positive gradient.

[0096] The specified critical temperature can be a temperature slightly higher than the melting point of ice. For example, the critical temperature could be 2 °C or higher.

[0097] If the temperature of the external heat exchanger 23 does not meet the condition for changing the defrosting operating frequency, step 20 (S20) is performed again.

[0098] In one example, if the current temperature of the external heat exchanger 23 is less than 2 °C, or if the current temperature of the external heat exchanger 23 is 2 °C or greater, but the gradient of the current temperature of the external heat exchanger 23 is a negative gradient, the control unit 63 can determine the defrosting operating frequency as the first defrosting operating frequency or defrosting operating holding frequency.

[0099] If the temperature of the external heat exchanger 23 meets the condition for changing the defrosting operating frequency, the compressor 21 can be driven at a second defrosting operating frequency in step 80 (S80). That is, in step 80 (S80), the control unit 63 changes the defrosting operating frequency from the first defrosting operating frequency to the second defrosting operating frequency and controls the compressor 21 so that it is driven at the second defrosting operating frequency. Then step 50 (S50) is performed again.

[0100] The second defrosting operating frequency is lower than the first defrosting operating frequency. That is, step 80 (S80) comprises reducing the defrosting operating frequency at the first time point based on the temperature of the external heat exchanger 23 of the compressor 21 and driving the compressor 21 at the reduced defrosting operating frequency.

[0101] For example, if the current temperature of the external heat exchanger 23 is 2 °C or greater and the gradient of the current temperature of the external heat exchanger 23 is a positive gradient, the control unit 63 can change the defrosting operating frequency from the first defrosting operating frequency to the second defrosting operating frequency.

[0102] The subject matter of the disclosure can be applied to all cooling and heating devices. In this case, a ratio of the first defrosting operating frequency to the second defrosting operating frequency can be determined based on the capacity of the external heat exchanger 23.

[0103] In particular, a relationship between the first de-icing operating frequency and the second de-icing operating frequency can be expressed as in Equation 1 below. fcomp2=A×fcomp1

[0104] Here, f refers to comp1 the first de-icing operating frequency, fcomp2 denotes the second de-icing operating frequency and A denotes a predefined ratio. A can be a real number greater than 0 and less than 1.

[0105] In this case, the capacity of the external heat exchanger 23 can be proportional to A. That is, if the capacity of the external heat exchanger 23 is large, the value of A increases, and if the capacity of the external heat exchanger 23 is small, the value of A decreases.

[0106] As a result of research conducted by the applicant, the second de-icing operating frequency can be half the first de-icing operating frequency. That is, the ratio (A) of the first de-icing operating frequency to the second de-icing operating frequency can be 1 / 2.

[0107] In one embodiment, the compressor 21 can be driven at the second defrosting operating frequency from the first point in time of the defrosting operation. That is, the compressor 21 can be driven at the first defrosting operating frequency before the first point in time and at the second defrosting operating frequency after the first point in time.

[0108] In another embodiment, the compressor 21 can be driven at a defrosting operating frequency that continuously decreases from the first defrosting operating frequency from the first time point of the defrosting operation, and at the second time point after the first time point. That is, from the time (the first time point) to change a defrosting operating frequency until the second time point of the defrosting operation, the compressor 21 can be driven at the defrosting operating frequency that continuously decreases from the first defrosting operating frequency, and from the second time point of the defrosting operation, the compressor 21 can be driven at the second defrosting operating frequency, as in Fig. 7 shown.

[0109] The defrosting operation of the cooling and heating device of the heat pump type is described below, specifically based on the above description, according to the disclosure.

[0110] The compressor 21 can usually be driven at a fixed defrosting operating frequency. Furthermore, the temperature of the outdoor heat exchanger 23 is not uniform, and during defrosting, frost may be removed from certain areas while remaining in others. Consequently, the compressor 21 can be driven for a predetermined period of time to remove frost from the entire area of ​​the outdoor heat exchanger 23.

[0111] If frost is present in most areas of the outdoor heat exchanger 23, the pressure of the compressor 21 does not increase. However, if frost remains only in some areas, the pressure of the compressor 21, which is driven at a fixed defrosting operating frequency, can increase rapidly. As the pressure of the compressor 21 increases, the current of the compressor 21 can also increase. Consequently, the compressor 21 can be overdriven, resulting in unnecessary power consumption. In particular, in an AWHP-based cooling and heating device, a pressure gradient can occur, decreasing from the first defrosting operating frequency, and from the second defrosting operation onward, the compressor 21 can be driven at the second defrosting operating frequency, as shown in Fig. 7 shown.

[0112] The defrosting operation of the cooling and heating device of the heat pump type according to the disclosure is described below, specifically on the basis of the above description.

[0113] The compressor 21 can usually be driven at a fixed defrosting operating frequency 10. Furthermore, the temperature of the external heat exchanger 23 is not uniform, and during defrosting, frost may be removed from certain areas while remaining in others. Consequently, the compressor 21 can be driven for a predetermined period of time to remove frost from the entire area of ​​the external heat exchanger 23.

[0114] If frost is present in most areas of the outdoor heat exchanger 23, the pressure of the compressor 21 does not increase. However, if frost remains only in some areas, the pressure of the compressor 21, which is driven at a fixed defrosting operating frequency, can increase rapidly. As the pressure of the compressor 21 increases, the current of the compressor 21 can also increase. Consequently, the compressor 21 can be overdriven, resulting in unnecessary power consumption. In particular, in an AWHP-based cooling and heating device, a pressure gradient of increasing pressure can occur. Compressor 21 may be steep because a surface area of ​​a coolant circulation pipe is narrow.

[0115] Fig. Figure 6 shows a graph of the operation of compressor 21, which operates at a fixed defrosting operating frequency. Here, A denotes a defrosting operating frequency of compressor 21, B denotes an input current of compressor 21, C denotes an output current of compressor 21, D denotes a high pressure of compressor 21, and E denotes a lower pressure of compressor 21.

[0116] With reference to Fig. 6. The pressure and current of compressor 21 increase rapidly in a later period of the de-icing operation.

[0117] To solve the above problem, in one embodiment the heat pump-type cooling and heating device can reduce the defrosting operating frequency at the first time of the defrosting operation based on a temperature of the external heat exchanger 23.

[0118] In particular, during an initial phase of defrosting operation, the control unit 63 can drive the compressor 21 at the first defrosting operating frequency. Furthermore, the control unit 63 can measure the temperature of the external heat exchanger 23 in real time to determine the first point in time for defrosting operation, which is a point at which the pressure and current of the compressor 21 increase rapidly due to frost remaining only in certain areas.

[0119] Here, the first time point can denote a time point at which the temperature of the external heat exchanger 23 reaches a critical temperature (e.g. 2 °C), or a time point at which a gradient of the temperature of the external heat exchanger 23 is a positive gradient, and the temperature of the external heat exchanger 23 reaches the critical temperature (e.g. 2 °C).

[0120] Then, at a specific first time, the control unit 63 can change the de-icing operating frequency from the first de-icing operating frequency to the second de-icing operating frequency. Furthermore, the control unit 63 can drive the compressor 21 at the second de-icing operating frequency from that first time. Alternatively, the control unit 63 can drive the compressor 21 at the continuously decreasing de-icing operating frequency from the first time and finally drive the compressor 21 at the second de-icing operating frequency.

[0121] Fig. Figure 7 shows a graph of the operation of compressor 21, which is driven at the defrosting operating frequency, decreasing from the first time point. Here, A denotes a defrosting operating frequency of compressor 21, B denotes an input current of compressor 21, C denotes an output current of compressor 21, D denotes a high pressure of compressor 21, and E denotes a lower pressure of compressor 21.

[0122] In comparison between Fig. 6 and Fig. 7. The high pressure of compressor 21 decreases to 6.1%, the input current of compressor 21 decreases to 67.9%, and the output current of compressor 21 decreases to 28.6%. This means that a rapid increase in the pressure and current of compressor 21 can be prevented during the latter part of the defrosting operation.

[0123] In summary, the heat pump-type cooling and heating device and its defrosting operating method, in one embodiment, can help prevent a rapid increase in compressor pressure and current by reducing the compressor's defrosting operating frequency at a specific point during the defrosting process. Consequently, the defrosting operation can be carried out reliably and unnecessary power consumption can be avoided.

[0124] The embodiments according to the present disclosure can be implemented in the form of program instructions to be executed by a variety of computer devices, such that they are recorded on a computer-readable recording medium. The computer-readable recording medium can comprise program instructions, files, data structures, and the like, independently or a combination thereof. The program instructions recorded on the medium can be specifically designed and configured for the subject matter of the disclosure, or program instructions that are well known to a person skilled in the art in the field with respect to computer software programs can be used. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD-ROMs and DVDs; and magneto-optical media such as...Flexible optical disks and hardware devices configured to store and execute program instructions, such as read-only memory (ROM), random-access memory (RAM), flash memory, and the like. Examples of program instructions include not only machine language code generated by a compiler but also high-level language code executed by the computer through an interpreter. The hardware devices described above can be configured to function as one or more software modules for performing the operations of the embodiments, and vice versa.

[0125] The components, features, and the like are described above with reference to the embodiments and accompanying drawings for a better understanding of the subject matter in this disclosure. However, the disclosure is not intended to limit the embodiments presented here. The embodiments can be modified and altered in various ways by a person skilled in the art within the scope of protection of the disclosure. Therefore, the technical idea of ​​the disclosure should not be considered as limited by the embodiments presented here, and equivalents and modifications derived from the scope of protection of the claims should be included in the technical idea of ​​the disclosure.

Claims

[1] Cooling and heating device comprising: a compressor (21) configured to compress coolant; an external heat exchanger (23) configured to exchange heat between outside air and coolant; an expansion part (24) configured to expand coolant; an internal heat exchanger (31) configured to exchange heat between the internal air or water and the coolant; and a control unit (63) configured to reduce the defrosting operating frequency of the compressor (21) during a defrosting operation based on the temperature of the external heat exchanger (23), wherein the control unit (63) is configured to continuously reduce the defrosting operating frequency of the compressor (21) during a time period between a first time point and a second time point of the defrosting operation, during which the temperature of the external heat exchanger (23) rises to a range of predetermined critical temperatures, and wherein the control unit (63) is configured to keep the de-icing operating frequency of the compressor (21) constant during a time interval between the second time point and a de-icing operating end point. [2] Cooling and heating device according to claim 1, wherein the control unit (63) is configured to determine a time as the first time of the defrosting operation at which a temperature of the external heat exchanger (23) reaches a predetermined critical temperature, wherein the control unit (63) is configured to reduce the defrosting operating frequency of the compressor (21) at the determined time during the defrosting operation of the cooling and heating device. [3] Cooling and heating device according to claim 1, wherein the control unit (63) is configured to determine a time point at which a temperature gradient of the external heat exchanger is a positive gradient and a temperature of the external heat exchanger reaches a predetermined critical temperature, as the first time point of the defrosting operation. [4] Cooling and heating device according to claim 2 or 3, wherein the critical temperature is 2 °C or greater. [5] Cooling and heating device according to one of the preceding claims, wherein the control unit (63) is configured to set the defrosting operating frequency of the compressor (21) to a first defrosting operating frequency at a time when the defrosting operation starts, wherein the control unit (63) is configured to change the defrosting operating frequency from the first defrosting operating frequency to a second defrosting operating frequency at the first time of the defrosting operation. [6] Cooling and heating device according to claim 5, wherein the second defrosting operating frequency is half the first defrosting operating frequency. [7] Cooling and heating device according to one of claims 5 or 6, wherein the compressor (21) is driven with the second defrosting operating frequency from the second time of defrosting operation, which is after the first time of defrosting operation, and wherein in the time interval between the first time of defrosting operation and the second time of defrosting operation the compressor (21) is driven with a defrosting operating frequency which continuously decreases from the first defrosting operating frequency. [8] Cooling and heating device according to one of the preceding claims, wherein, if the temperature of the external heat exchanger (23) is maintained within the range of specified critical temperatures during a specified critical time period, the control unit (63) is configured to control the compressor (21) such that the compressor (21) terminates the defrosting operation. [9] Cooling and heating device according to any of the preceding claims, further comprising: at least one sensor (62) configured to measure the temperature of the external heat exchanger (23) and transmit it to the control unit (63). [10] Defrosting operating method of a cooling and heating device comprising a compressor (21) configured to compress refrigerant, an external heat exchanger (23) configured to exchange heat between outside air and refrigerant, at least one sensor (62) configured to measure a temperature of the external heat exchanger (23), an expansion part (23) configured to expand refrigerant, an internal heat exchanger (31) configured to exchange heat between inside air or water and the refrigerant, and a control unit (63) configured to control an operating frequency of the compressor (21) depending on an operating mode of the cooling and heating device, wherein the method comprises: Driving the compressor (21) at a first defrosting operating frequency; Measuring the temperature of the external heat exchanger (23) by means of at least one sensor (62); Determining a time to change a defrosting operating frequency of the compressor based on the measured temperature of the external heat exchanger (23) by the control unit (63), continuous reduction of the defrosting operating frequency of the compressor (21) by the control unit (63) during a time period between a first time point and a second time point of the defrosting operation, during which the temperature of the external heat exchanger (23) rises to a range of predetermined critical temperatures, and Maintaining the defrosting operating frequency of the compressor (21) constantly by the control unit (63) during a time period between the second time point and an endpoint of the defrosting operation. [11] De-icing operating method according to claim 10, further comprising driving the compressor (21) with a de-icing operating frequency which is lower than the first de-icing operating frequency, in a time period after the time to change a de-icing operating frequency. [12] Defrosting operating method according to claim 10 or 11, wherein determining the time to change a defrosting operating frequency of the compressor (21) comprises determining a time at which a gradient of the external heat exchanger (23) is a positive gradient and a temperature of the external heat exchanger reaches a predetermined critical temperature, as the time to change a defrosting operating frequency. [13] De-icing operating method according to one of claims 10-12, wherein driving the compressor (21) comprises: Driving the compressor (21) with a defrosting operating frequency that continuously decreases from the first defrosting operating frequency, from the time of changing a defrosting operating frequency until the second time of defrosting operation and / or Driving the compressor (21) with a second de-icing operating frequency that is lower than the first de-icing operating frequency, from the second time of the de-icing operation.

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