JP2011080741A - Heat pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump device capable of suppressing evaporation pressure of a heat exchanger when a heat exchange target of the heat exchanger acting as an evaporator in defrosting is high temperature hot water, and capable of maintaining reliability of the heat pump device. <P>SOLUTION: The heat pump device has a heat pump cycle A constituted by a compressor 100, a four-way valve 200, a refrigerant-water heat exchanger 300, an expansion valve 400, and an outdoor heat exchanger 500 using outside air as a heat source. During defrosting for removing frost on the outdoor heat exchanger 500, the four-way valve 200 is switched, and the flow direction of the refrigerant is opposite from the one in heating, and an opening of the expansion valve 400 is adjusted based on detection information having a correlation with a temperature of hot water flowing in the refrigerant-water heat exchanger 300, for example, a condensation temperature of the refrigerant-water heat exchanger 300. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to defrosting of a heat pump device.

  Conventionally, in the defrosting operation of the heat pump device, the refrigerant flow is switched by the four-way switching valve in the opposite direction to that in the heating operation (during the hot water supply operation in which the heat source side heat exchanger acts as an evaporator). There is known a reverse defrosting method in which a defrosting of the heat source side heat exchanger is performed by flowing the discharged refrigerant in the heat source side heat exchanger.

  The heat pump device using the reverse defrosting method includes a heat pump type hot water supply device. As shown in FIG. 7, during the hot water supply operation, the high-temperature and high-pressure refrigerant discharged from the compressor 1 Then, it is supplied to the hot water supply heat exchanger 2, and water is heated by heat exchange between the refrigerant of the hot water supply heat exchanger 2 and water. Next, the refrigerant is decompressed by the expansion valve 3, supplied to the heat source side heat exchanger 4, absorbs heat from the outside air and evaporates, and then returns to the compressor 1.

  Since the heat source side heat exchanger 4 acts as an evaporator during this hot water supply operation, if the outside air temperature is low and frost formation occurs in the heat source side heat exchanger 4, the four-way switching valve 14 is different from that during the hot water supply operation. The flow is switched to the reverse direction, and the process moves to the defrosting operation.

  During the defrosting operation, the high-temperature and high-pressure refrigerant discharged from the compressor 1 is supplied to the heat source side heat exchanger 4 through the four-way switching valve 14, and the heat of the refrigerant flowing through the heat source side heat exchanger 4 is used on the heat source side. The frost on the heat exchanger 4 is defrosted. Next, the refrigerant is supplied to the hot water supply heat exchanger 2 through the expansion valve 3 to evaporate, absorbs heat from the hot water, and then returns to the compressor 1 (see, for example, Patent Document 1).

  However, in the reverse defrosting method of Patent Document 1, since the refrigerant is supplied to the hot water supply heat exchanger 2 without being controlled by the expansion valve 3 during the defrosting operation, the heat exchange of the hot water supply heat exchanger 2 is performed. When the object is hot water having a temperature higher than that of air, the evaporation pressure of the refrigerant in the hot water supply heat exchanger 2 that functions as an evaporator may be excessively increased. As a result, there is a drawback in that the compressor 1 is burdened and the reliability of the heat pump device is reduced.

Japanese Patent Laid-Open No. 2001-108256 (pages 4-6, FIG. 4)

  In view of the above problems, the present invention suppresses the evaporation pressure of the heat exchanger and maintains the reliability of the heat pump device when the heat source of the heat exchanger acting as an evaporator is hot water during defrosting operation. It is an object of the present invention to provide a heat pump device that can perform such a process.

  In order to solve the above problems, the present invention is a heat pump device having a heat pump cycle comprising a compressor, a four-way valve, a refrigerant-water heat exchanger, an expansion valve, and an outdoor heat exchanger, During the defrosting operation for removing frost on the outdoor heat exchanger, the temperature of the hot water flowing in the refrigerant-water heat exchanger is changed by switching the four-way valve so that the flow direction of the refrigerant is opposite to that during the heating operation. The opening of the expansion valve is adjusted on the basis of detection information correlated with.

  Invention of Claim 2 is the heat pump apparatus of Claim 1, Comprising: The said detection information is the condensation temperature of the said refrigerant | coolant-water heat exchanger, The opening degree of the said expansion valve is the said condensation temperature predetermined temperature. The first opening in the above case is configured to be smaller than the second opening when the temperature is lower than the predetermined temperature.

  Invention of Claim 3 is the heat pump apparatus of Claim 1, Comprising: The said detection information is the discharge pressure of the said compressor, The opening degree of the said expansion valve is the case where the said discharge pressure is more than predetermined pressure. The first opening is made smaller than the second opening when the pressure is less than the predetermined pressure.

  The invention according to claim 4 is the heat pump device according to claim 2 or claim 3, wherein the outlet temperature of the outdoor heat exchanger reaches a predetermined first temperature or more in the case of the first opening degree. When the second defrosting operation is performed, the defrosting operation is terminated when the outlet temperature of the outdoor heat exchanger reaches a predetermined second temperature higher than the first temperature. It is the structure characterized by complete | finishing.

  According to the first to third aspects of the invention, during the defrosting operation, even if the heat exchange target in the heat exchanger acting as an evaporator is high-temperature hot water, heat exchange is performed by controlling the expansion valve. Since the evaporation pressure of the vessel can be adjusted, the compressor is not burdened and the reliability of the heat pump device can be maintained.

  According to this invention of Claim 4, by making the exit temperature of the outdoor heat exchanger for the completion | finish judgment of the defrost operation in the case of the 1st opening lower than that in the case of the 2nd opening, Since the useless defrosting operation is eliminated and the condensation pressure of the outdoor heat exchanger can be suppressed, the compressor is not burdened and the reliability of the heat pump device can be maintained.

It is a circuit block diagram which shows the heat pump apparatus by this invention. It is a flowchart which shows 1st Example of control of the heating operation of a heat pump apparatus by this invention, and a defrost operation. It is a figure which shows an example of the defrost operation mode and defrost operation conditions of the heat pump apparatus by this invention. It is the flowchart which changed a part of 1st Example of control of the heating operation of a heat pump apparatus by this invention, and a defrost operation. It is a flowchart which shows 2nd Example of control of the heating operation of a heat pump apparatus by this invention, and a defrost operation. It is the flowchart which changed a part of 2nd Example of control of the heating operation of a heat pump apparatus by this invention, and a defrost operation. It is a circuit block diagram which shows the conventional heat pump apparatus.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The heat pump device according to the present invention is a device that generates hot water by heating water by the action of a refrigerant circuit during heating operation, and uses this hot water for hot water supply, floor heating, a radiator, and the like.

  As shown in FIG. 1, the heat pump apparatus includes a compressor 100, a four-way valve 200, a refrigerant-water heat exchanger 300, an expansion valve 400, and an outdoor heat exchanger 500 (external heat source side heat in the background art). A refrigerant circuit that sequentially connects a refrigerant pipe, a circulation pump 600, a refrigerant-water heat exchanger 300 (corresponding to the heat exchanger 2 for hot water supply in the background art), and a heating terminal 700 sequentially through a water distribution pipe. It has a heat pump cycle A comprising a hot water circuit to be connected. In the present embodiment, a floor heating panel is formed as the heating terminal 700, and hot water is circulated through the floor heating panel.

  In the refrigerant circuit, a compressor discharge pressure sensor Sp that detects the discharge pressure of the compressor 100 is disposed between the four-way valve 200 and the refrigerant-water heat exchanger 300. Further, a refrigerant-water heat exchanger temperature sensor St1 for detecting the condensation temperature of the refrigerant-water heat exchanger 300 during heating operation is disposed in the refrigerant-water heat exchanger 300, and the outdoor in the refrigerant flow direction during heating operation. An outdoor heat exchanger temperature sensor St2 for detecting the refrigerant temperature at the inlet of the heat exchanger (hereinafter referred to as the inlet temperature of the outdoor heat exchanger 500) is disposed in the vicinity of the inlet of the outdoor heat exchanger 500 on the expansion valve 400 side. . The outdoor heat exchanger temperature sensor St2 is also a sensor that detects the refrigerant temperature at the outlet of the outdoor heat exchanger in the refrigerant flow direction during the defrosting operation (hereinafter referred to as the outlet temperature of the outdoor heat exchanger 500). . Furthermore, an outdoor fan 800 for introducing outside air to be heat exchanged into the outdoor unit is disposed in the vicinity of the outdoor heat exchanger 500.

  And the heat pump apparatus has the controller 900 which controls the heating operation and defrost operation which consist of microcomputers. The controller 900 performs arithmetic processing based on detection signals of the compressor discharge pressure sensor Sp, the refrigerant-water heat exchanger temperature sensor St1, and the outdoor heat exchanger temperature sensor St2, and based on the results, the compressor 100 and the four-way valve 200 are processed. The control signal is output to the expansion valve 400 and the outdoor fan 800.

  The operation of the heat pump apparatus described above will be described. First, basic operations of the heating operation and the defrosting operation will be described with reference to FIG. When starting the heating operation, the controller 900 outputs a control signal to the four-way valve 200, turns on the four-way valve 200 so that the flow direction of the refrigerant is in the direction of the solid arrow, and then operates the compressor 100. By starting, the outdoor heat exchanger 500 functions as an evaporator and the refrigerant-water heat exchanger 300 functions as a condenser.

  The high-temperature and high-pressure refrigerant discharged from the compressor 100 is supplied to the refrigerant-water heat exchanger 300 through the four-way valve 200, and heats the water by heat exchange between the refrigerant and water by the refrigerant-water heat exchanger 300. At this time, the high-temperature and high-pressure refrigerant is condensed in the refrigerant-water heat exchanger 300. The water flowing in the hot water circuit as indicated by the solid line arrow is heated by the heat of the refrigerant to become hot water.

  Thereafter, the refrigerant is decompressed by the expansion valve 400 to be in a liquid phase state or a two-phase state, supplied to the outdoor heat exchanger 500, absorbs heat from the outside air, evaporates, and returns to the compressor 100 through the four-way valve 200. During the heating operation, the controller 900 adjusts the flow rate of the refrigerant so that the heat radiation from the refrigerant to the hot water in the refrigerant-water heat exchanger 300 and the heat absorption from the outside air of the refrigerant in the outdoor heat exchanger 500 have an optimum efficiency. In order to adjust, the opening degree of the expansion valve 400 is controlled. In addition, the controller 900 turns on the outdoor fan 800 and introduces outside air into the outdoor heat exchanger 500 to promote heat exchange between the refrigerant and the outside air by the outdoor heat exchanger 500.

  During the heating operation, when the outdoor heat exchanger temperature sensor St2 detects the inlet temperature of the outdoor heat exchanger 500 that is equal to or lower than a predetermined temperature, it is determined that frost formation has occurred in the outdoor heat exchanger 500, and the four-way valve 200 Thus, the process shifts to the reverse defrosting type defrosting operation in which the flow direction of the refrigerant is switched to the reverse direction during the heating operation.

  When shifting from the heating operation to the defrosting operation, the controller 900 determines the shift to the defrosting operation based on the detection signal of the inlet temperature of the outdoor heat exchanger 500 by the outdoor heat exchanger temperature sensor St2, and compresses it. The operation of the compressor 100 is stopped, the four-way valve 200 is turned off so that the flow direction of the refrigerant becomes the direction of the dotted arrow, and then the operation of the compressor 100 is started, whereby the refrigerant-water heat exchanger 300 is The evaporator and the outdoor heat exchanger 500 are caused to function as a condenser.

  When the operation of the compressor 100 is started and the defrosting operation is started, the high-temperature and high-pressure refrigerant discharged from the compressor 100 is supplied to the outdoor heat exchanger 500 through the four-way valve 200, and is supplied to the outdoor heat exchanger 500. The frost formation of the outdoor heat exchanger 500 is defrosted by the heat of the flowing refrigerant. At this time, the high-temperature and high-pressure refrigerant is condensed in the outdoor heat exchanger 500.

  Thereafter, the refrigerant is supplied to the refrigerant-water heat exchanger 300 via the expansion valve 400, absorbs heat from the hot water and evaporates, and returns to the compressor 100 via the four-way valve 200. In the present invention, when the operation is shifted from the heating operation to the defrosting operation, the operation of the compressor 100 is stopped and the four-way valve 200 is turned off. By adjusting the opening degree of the expansion valve 400 based on the condensing temperature or condensing pressure of a certain refrigerant, the evaporating pressure of the refrigerant in the refrigerant-water heat exchanger 300 during the defrosting operation is prevented from becoming too large. .

  In the present invention, during the heating operation, when it is detected that the inlet temperature of the outdoor heat exchanger 500 has become equal to or lower than a predetermined temperature, the operation of the compressor 100 is stopped, the four-way valve 200 is turned off, and then the expansion is performed. The defrosting operation is started by adjusting the opening degree of the valve 400 and starting the operation of the compressor 100. After the defrosting operation is continued for a predetermined time, when the outlet temperature of the outdoor heat exchanger 500 detects that the temperature rises from a predetermined temperature to a predetermined temperature or more, the operation of the compressor 100 is stopped and the four-way valve is stopped. By turning on 200, the defrosting operation is terminated.

  In order to start the above-described defrosting operation, as shown in FIG. 3, the heat pump device of the present invention has a hot water discharge mode when the hot water temperature just before entering the defrosting operation is high, and hot water just before entering the defrosting operation. There are two types of defrosting operation modes, a low temperature hot water mode when the temperature is low, and the heat pump device performs the defrosting operation by selecting the high temperature hot water mode or the low temperature hot water mode. The defrosting operation in the high-temperature tapping mode or low-temperature tapping mode is the numerical value of each defrosting operation condition of refrigerant-water heat exchanger condensing temperature, number of expansion valve pulses, compressor rotation speed, refrigerant-water heat exchanger evaporating pressure. The operation is controlled accordingly. In addition, among the numerical values of the defrosting operation conditions, the number of expansion valve pulses is different in the high temperature hot water mode and the low temperature hot water mode.

  Next, the defrosting operation characteristic of the present invention will be described with reference to FIGS. 2 and 4, S represents a step, and the numeral represents a step number. As a first embodiment of the present invention, a heat pump device that uses the detection result of the refrigerant-water heat exchanger temperature sensor St1 and a heat pump device that uses the detection result of the compressor discharge pressure sensor Sp to select the defrosting operation mode. These two embodiments will be described. Moreover, about the heating capability of the heat pump apparatus demonstrated in these two Example, it demonstrates as the heat pump apparatus using the detection result of the compressor discharge pressure sensor Sp is an apparatus with a larger heating capability.

  First, the heat pump device using the detection result of the refrigerant-water heat exchanger temperature sensor St1 will be described. As shown in FIG. 2, the controller 900 determines whether or not the heating operation is being performed based on whether or not the compressor 100 and the four-way valve 200 are ON (S1). If the heating operation is being performed (S1-YES), the process proceeds to S2, and if the heating operation is not being performed (S1-NO), the routine is terminated. In S2, the inlet temperature To of the outdoor heat exchanger 500 is detected, and if the inlet temperature To is −10 ° C. or lower (S2-YES), the transition to the defrosting operation is determined and the routine proceeds to S3. If To is not -10 degrees C or less (S2-NO), the continuation of heating operation will be determined and a routine will be complete | finished.

  In the present embodiment, the detection of the inlet temperature To of the outdoor heat exchanger 500 is detected by the outdoor heat exchanger temperature sensor St2, and the controller 900 performs the defrosting operation based on the detection signal of the outdoor heat exchanger temperature sensor St2. Determine whether or not to move to In S3, the condensing temperature Tw of the refrigerant-water heat exchanger 300 is detected by the refrigerant-water heat exchanger temperature sensor St1, and if the condensing temperature Tw is 37 ° C. or higher (S3-YES), the process proceeds to S4 to condense If temperature Tw is less than 37 degreeC (S3-NO), it will transfer to S7.

  In the present embodiment, the hot water temperature is indirectly detected by detecting the condensation temperature Tw of the refrigerant-water heat exchanger 300 having a correlation with the hot water temperature. In S4, the controller 900 starts operation control in the high-temperature hot water mode, turns off the outdoor fan 800, and stops the compressor 100. The controller 900 turns off the four-way valve 200 after a predetermined time has elapsed from the stop of the compressor 100 (S5) and throttles the expansion valve 400 (S6). In S6, the controller 900 outputs a control signal for setting the number of expansion valve pulses to, for example, 150 pulses to the expansion valve 400, thereby narrowing the opening degree of the expansion valve 400.

  On the other hand, in S7, similarly to S4, the controller 900 starts operation control in the low-temperature hot water mode, turns off the outdoor fan 800, and stops the compressor 100. The controller 900 turns off the four-way valve 200 after a predetermined time has elapsed from the stop of the compressor 100 (S8), and fully opens the expansion valve 400 (S9). In S9, the controller 900 outputs a control signal for setting the number of expansion valve pulses to, for example, 480 pulses to the expansion valve 400 to fully open the opening of the expansion valve 400.

  The opening degree of the expansion valve 400 is adjusted by outputting the above-mentioned control signal to a stepping motor that opens and closes the valve. The expansion valve 400 is fully opened when a control signal of 480 pulses is output to the stepping motor, and is 0 pulse. When the number of expansion valve pulses increases from 0 pulse to 480 pulses, the opening degree of the expansion valve 400 also increases to correspond to this. It is controlled to become.

  Furthermore, as described above, when the condensation temperature Tw is less than 37 ° C., the opening of the expansion valve 400 is fully opened (480 pulses) to supply the highest possible refrigerant to the outdoor heat exchanger 500. The evaporating pressure of the refrigerant-water heat exchanger 300 exhibits the defrosting capability without exceeding the upper limit value. On the other hand, as described above, when the condensation temperature Tw is equal to or higher than 37 ° C., the evaporation pressure of the refrigerant-water heat exchanger 300 is prevented from exceeding the upper limit value by narrowing the opening degree of the expansion valve 400 (150 pulses). ing.

  After adjusting the opening degree of the expansion valve 400 in S6 and S9, the controller 900 rotates the compressor 100 and starts the defrosting operation (S10). In S10, the controller 900 outputs a control signal for setting the compressor rotation speed to, for example, 70 rps to the compressor 100. Thereafter, in S11, the controller 900 determines whether or not the outlet temperature To of the outdoor heat exchanger 500 acquired by the outdoor heat exchanger temperature sensor St2 is higher than 15 ° C. If the outlet temperature To of the outdoor heat exchanger 500 is higher than 15 ° C (S11-YES), the controller 900 stops the compressor 100 (S12), and if the outlet temperature To of the outdoor heat exchanger 500 is 15 ° C or less. If (S11-NO), step S11 is repeatedly executed. The controller 900 turns on the four-way valve 200 after a predetermined time has elapsed after stopping the compressor 100 in S12, and ends the defrosting operation (S13). Next, the expansion valve 400 is adjusted to the opening degree during the heating operation immediately before entering the defrosting operation (S14). After adjusting the opening degree of the expansion valve 400 in S14, the controller 900 turns on the outdoor fan 800 (S15), and returns from the defrosting operation to the heating operation.

  Next, a heat pump device using the detection result of the compressor discharge pressure sensor Sp will be described. As shown in FIG. 4, only the steps S3 ′, S6 ′, and S9 ′ different from the heat pump device using the detection result of the refrigerant-water heat exchanger temperature sensor St1 described above will be described, and the description of the common steps will be described. Omitted. The difference from the heat pump device using the detection result of the refrigerant-water heat exchanger temperature sensor St1 is a heat pump device having a large heating capacity as shown in FIG. The point is that the values of the exchanger condensing temperature and the number of expansion valve pulses are changed. In addition, about the numerical value of each defrost operation condition, it is suitably set not only by the numerical value demonstrated in the present Example but according to specifications, such as the compressor 100, the refrigerant | coolant-water heat exchanger 300, the expansion valve 400. .

  Hereinafter, each step of S3 ', S6', and S9 'will be described. In the flowchart of FIG. 4, in S3 ′, the condensation pressure of the refrigerant-water heat exchanger 300 (slightly smaller than the discharge pressure of the compressor 100) is detected using the compressor discharge pressure sensor Sp, and experimentally preliminarily detected. The detected condensing pressure is converted into a condensing temperature according to a predetermined condensing pressure and condensing temperature conversion table. If the condensing temperature Tw of the converted refrigerant-water heat exchanger 300 is 50 ° C. or higher (S3′-YES), the process proceeds to S4, and if the condensing temperature Tw is lower than 50 ° C. (S3′-NO), The process proceeds to S7.

  The above conversion table is stored in a storage means (not shown) in the controller 900, and the controller 900 converts the condensing pressure into the condensing temperature according to the conversion table. As described above, in S3 ′, the hot water temperature can be indirectly acquired by detecting the condensing pressure of the refrigerant-water heat exchanger 300 correlated with the condensing temperature and converting the condensing pressure into the condensing temperature. It has become a feature.

  In S <b> 6 ′, a control signal for setting the number of expansion valve pulses to, for example, 200 pulses is output from the controller 900 to the expansion valve 400 to reduce the opening of the expansion valve 400. In S <b> 9 ′, a control signal for setting the number of expansion valve pulses to, for example, 400 pulses is output from the controller 900 to the expansion valve 400, and the opening degree of the expansion valve 400 is slightly reduced without being fully opened. Here, the reason why the expansion valve 400 is slightly throttled is that, if the heating capacity is large, the flow rate of the refrigerant increases, so that the refrigerant noise flowing through the refrigerant is suppressed.

  In the defrosting operation of the heat pump apparatus described above, the hot water temperature may be detected directly using a hot water temperature sensor instead of detecting the condensation temperature Tw at S3 or S3 ′. .

  Further, in the defrosting operation of the heat pump apparatus described above, if the inlet temperature To of the outdoor heat exchanger 500 is −10 ° C. or lower, the transition to the defrosting operation is determined, and the inlet temperature To is −10 ° C. If not below, the continuation of the heating operation is determined, but the transition condition to the defrosting operation is not limited to this, and for example, any one of the following three transition conditions: You may choose one to apply.

  (1) When the inlet temperature To of the outdoor heat exchanger 500 becomes −25 ° C. or lower during the heating operation, the transition to the defrosting operation is determined. In other cases, the continuation of the heating operation is determined.

  (2) When the inlet temperature To of the outdoor heat exchanger 500 is lower than the temperature 10 minutes after the start of the operation of the compressor 100 during the heating operation by a predetermined time, and when the temperature drops by 5 ° C. or more, the defrosting operation is started. In other cases, it is determined to continue the heating operation.

  (3) When the inlet temperature To of the outdoor heat exchanger 500 has a temperature drop of 2 ° C. or more during heating operation, for example, at a temperature detected every 5 minutes, a temperature of 2 ° C. or more is detected. The transition to the frost operation is determined, and otherwise, the continuation of the heating operation is determined.

  In the present embodiment described above, the refrigerant is controlled by the expansion valve 400 based on the detection information correlated with the temperature of the hot water flowing through the refrigerant-water heat exchanger 300 during the defrosting operation. The refrigerant depressurized by the expansion valve 400 is supplied to the refrigerant-water heat exchanger 300 acting as an evaporator. As a result, even if the hot water temperature is high, the refrigerant-water heat exchanger 300 is used. There is no possibility that the evaporation pressure of the liquid becomes too large. For example, as shown in FIG. 3, the evaporation pressure of the refrigerant-water heat exchanger 300 can be suppressed within an upper limit value of 1.6 MPa that does not exceed the use range of the compressor 100. Since it does not exceed the range, the operation at a low compression ratio can be prevented without increasing the suction pressure of the compressor 100 too much. Moreover, in this embodiment, since the heat exchange object of the heat exchanger that acts as an evaporator during the defrosting operation is hot water having a temperature higher than that of air, the control is unnecessary in the defrosting operation of the conventional air conditioner. There is a feature that the opening degree of the expansion valve 400 is adjusted.

  Furthermore, in this embodiment described above, when shifting to the defrosting operation, the four-way valve 200 is turned OFF after a predetermined time has elapsed from the stop of the compressor 100, and when the defrosting operation is terminated, The four-way valve 200 is turned on after a predetermined time has elapsed since the compressor 100 was stopped. As a result, when the four-way valve 200 is switched, the differential pressure between the high-pressure side and the low-pressure side of the four-way valve 200 can be reduced, so that the slide valve can move smoothly and the valve switching sound can be reduced.

  The heat pump device according to the present invention described above is a heat pump device having a heat pump cycle A including the compressor 100, the four-way valve 200, the refrigerant-water heat exchanger 300, the expansion valve 400, and the outdoor heat exchanger 500. During the defrosting operation for removing frost formation on the outdoor heat exchanger 500, the four-way valve 200 is switched to reverse the flow direction of the refrigerant during the heating operation and the hot water flowing in the refrigerant-water heat exchanger 300 It is characterized in that the opening degree of the expansion valve 400 is adjusted based on detection information correlated with temperature.

  The detection information is the condensation temperature of the refrigerant-water heat exchanger 300, and the opening degree of the expansion valve 400 is the first opening degree when the condensation temperature is equal to or higher than a predetermined temperature (for example, the number of expansion valve pulses is 150 pulses). It is characterized by being made smaller than the second opening (for example, the number of expansion valve pulses is 480 pulses) when the temperature is lower than the predetermined temperature. The detection information is the discharge pressure of the compressor 100, and the opening of the expansion valve 400 is the first opening when the discharge pressure is equal to or higher than a predetermined pressure (for example, the number of expansion valve pulses is 200 pulses). It is characterized by being made smaller than the second opening (for example, the number of expansion valve pulses is 400 pulses) when the pressure is less than the pressure.

  Thereby, at the time of defrosting operation, even if the temperature of the hot water that is the heat exchange target of the refrigerant-water heat exchanger 300 that acts as an evaporator is high, the opening degree of the expansion valve 400 is controlled to make the refrigerant-water Since the evaporation pressure of the heat exchanger 300 can be adjusted, the compressor 100 is not burdened and the reliability of the heat pump device can be maintained.

  Next, a second embodiment of the defrosting operation characteristic of the present invention will be described with reference to FIGS. 5 and 6, S represents a step, and the numeral represents a step number. As a second embodiment of the present invention, a heat pump device that uses the detection result of the refrigerant-water heat exchanger temperature sensor St1 and a heat pump device that uses the detection result of the compressor discharge pressure sensor Sp for selecting the defrosting operation mode. These two embodiments will be described. Moreover, about the heating capability of the heat pump apparatus demonstrated in these two Example, it demonstrates as the heat pump apparatus using the detection result of the compressor discharge pressure sensor Sp is an apparatus with a larger heating capability.

  Further, in this embodiment, the effects of adjusting the opening of the expansion valve 400 during the defrosting operation of the configuration, basic operation and defrosting operation conditions of the heat pump device and the heat pump device are shown in FIGS. Since this is the same as the first embodiment described with reference to FIG. The difference from the first embodiment described with reference to FIGS. 1 to 4 is that the numerical value of the defrosting operation end determination condition is changed in accordance with the adjusted opening degree of the expansion valve 400.

  First, the heat pump device using the detection result of the refrigerant-water heat exchanger temperature sensor St1 will be described. As illustrated in FIG. 5, the controller 900 determines whether the heating operation is being performed based on whether the compressor 100 and the four-way valve 200 are ON (S20). If the heating operation is being performed (S20-YES), the process proceeds to S21. If the heating operation is not being performed (S20-NO), the routine is terminated. In S21, the inlet temperature To of the outdoor heat exchanger 500 is detected, and if the inlet temperature To is −10 ° C. or lower (S21—YES), the transition to the defrosting operation is determined and the routine proceeds to S22. If To is not −10 ° C. or lower (S21—NO), the continuation of the heating operation is determined and the routine is terminated.

  The detection of the inlet temperature To of the outdoor heat exchanger 500 in S21 is detected by the outdoor heat exchanger temperature sensor St2, and the controller 900 shifts to the defrosting operation based on the detection signal of the outdoor heat exchanger temperature sensor St2. Determine the necessity of In S22, the condensing temperature Tw of the refrigerant-water heat exchanger 300 is detected by the refrigerant-water heat exchanger temperature sensor St1, and if the condensing temperature Tw is 37 ° C. or higher (S22-YES), the process proceeds to S23 to condense. If temperature Tw is less than 37 degreeC (S22-NO), it will transfer to S28.

  In S22, the hot water temperature is indirectly detected by detecting the condensation temperature Tw of the refrigerant-water heat exchanger 300 correlated with the hot water temperature. In S23, the controller 900 starts operation control in the high-temperature hot-water supply mode, turns off the outdoor fan 800, and stops the compressor 100. The controller 900 turns off the four-way valve 200 after a predetermined time has elapsed from the stop of the compressor 100 (S24) and throttles the expansion valve 400 (S25). In S25, the controller 900 outputs a control signal for setting the number of expansion valve pulses to, for example, 150 pulses to the expansion valve 400, thereby narrowing the opening degree of the expansion valve 400.

  After reducing the opening degree of the expansion valve 400 in S25, the controller 900 rotates the compressor 100 and starts the defrosting operation (S26). In S <b> 26, the controller 900 outputs a control signal for setting the compressor rotational speed to, for example, 70 rps to the compressor 100. Thereafter, in S27, the controller 900 determines whether or not the outlet temperature To of the outdoor heat exchanger 500 acquired by the outdoor heat exchanger temperature sensor St2 is higher than 10 ° C. If the outlet temperature To of the outdoor heat exchanger 500 is higher than 10 ° C (S27-YES), the process proceeds to S33, and if the outlet temperature To of the outdoor heat exchanger 500 is 10 ° C or lower (S27-NO), Repeat steps.

  On the other hand, in S28, as in S23, the controller 900 starts operation control in the low-temperature hot water mode, turns off the outdoor fan 800, and stops the compressor 100. The controller 900 turns off the four-way valve 200 after a predetermined time has elapsed from the stop of the compressor 100 (S29), and fully opens the expansion valve 400 (S30). In S30, a control signal for setting the number of expansion valve pulses to, for example, 480 pulses is output from the controller 900 to the expansion valve 400 to fully open the opening of the expansion valve 400.

  After fully opening the opening of the expansion valve 400 in S30, the controller 900 rotates the compressor 100 and starts the defrosting operation (S31). In S <b> 31, the controller 900 outputs a control signal for setting the compressor rotational speed to, for example, 70 rps to the compressor 100. Thereafter, in S32, the controller 900 determines whether or not the outlet temperature To of the outdoor heat exchanger 500 acquired by the outdoor heat exchanger temperature sensor St2 is higher than 15 ° C. If the outlet temperature To of the outdoor heat exchanger 500 is higher than 15 ° C (S32-YES), the process proceeds to S33, and if the outlet temperature To of the outdoor heat exchanger 500 is 15 ° C or lower (S32-NO), the process proceeds to S32. Repeat steps.

  After determining that the outlet temperature To of the outdoor heat exchanger 500 is higher than 10 ° C. or 15 ° C. in S 27 and S 32, the controller 900 stops the compressor 100 (S 33), and turns on the four-way valve 200 after a predetermined time. The defrosting operation is terminated (S34). Next, the expansion valve 400 is adjusted to the opening degree at the time of heating operation immediately before entering the defrosting operation (S35). After adjusting the opening degree of the expansion valve 400 in S35, the controller 900 turns on the outdoor fan 800 (S36), and returns from the defrosting operation to the heating operation.

  Next, a heat pump device using the detection result of the compressor discharge pressure sensor Sp will be described. As shown in FIG. 6, only the steps S22 ′, S25 ′, and S30 ′ different from the heat pump device using the detection result of the refrigerant-water heat exchanger temperature sensor St1 described above will be described, and the description of the common steps will be described. Omitted. The difference from the heat pump device using the detection result of the refrigerant-water heat exchanger temperature sensor St1 is a heat pump device having a large heating capacity as shown in FIG. The point is that the values of the exchanger condensing temperature and the number of expansion valve pulses are changed.

  Hereinafter, each step of S22 ', S25', and S30 'will be described. In the flowchart of FIG. 6, in S22 ′, the compressor discharge pressure sensor Sp is used to detect the condensing pressure of the refrigerant-water heat exchanger 300 (slightly smaller than the discharge pressure of the compressor 100), and experimentally in advance. The detected condensing pressure is converted into a condensing temperature according to a predetermined condensing pressure and condensing temperature conversion table. If the condensing temperature Tw of the converted refrigerant-water heat exchanger 300 is 50 ° C. or more (S22′-YES), the process proceeds to S23, and if the condensing temperature Tw is less than 50 ° C. (S22′-NO), The process proceeds to S28.

  The above conversion table is stored in a storage means (not shown) in the controller 900, and the controller 900 converts the condensing pressure into the condensing temperature according to the conversion table. As described above, in S22 ′, it is possible to indirectly detect the hot water temperature by detecting the condensation pressure of the refrigerant-water heat exchanger 300 having a correlation with the condensation temperature and converting the condensation pressure into the condensation temperature. It has become a feature.

  In S <b> 25 ′, the controller 900 outputs a control signal for setting the number of expansion valve pulses to, for example, 200 pulses to the expansion valve 400 to narrow the opening degree of the expansion valve 400. In S30 ', a control signal for setting the number of expansion valve pulses to 400, for example, is output from the controller 900 to the expansion valve 400, and the opening degree of the expansion valve 400 is slightly reduced without being fully opened. Here, the reason why the expansion valve 400 is slightly throttled is that, if the heating capacity is large, the flow rate of the refrigerant increases, so that the refrigerant noise flowing through the refrigerant is suppressed.

  In the present embodiment that has been described above, the compressor 100 is stopped and the defrosting operation is ended when the opening degree of the expansion valve 400 is reduced during the defrosting operation and when it is fully opened (or slightly reduced). The numerical value of the judgment condition was changed. The numerical value of the condition for determining the outlet temperature To of the outdoor heat exchanger 500 is, for example, 10 ° C. when the opening degree of the expansion valve 400 is reduced, and when the opening degree of the expansion valve 400 is fully opened (or slightly reduced). For example, by setting each at 15 ° C., there is no possibility that the condensation pressure of the outdoor heat exchanger 500 becomes too large during the defrosting operation, and the burden on the compressor 100 can be reduced.

  More specifically, when the opening degree of the expansion valve 400 is reduced during the defrosting operation, the degree of supercooling of the refrigerant at the outdoor heat exchanger outlet becomes larger than that when the refrigerant is fully opened. If the outlet temperature To is the same value, the condensation temperature of the outdoor heat exchanger 500 at the time of judging the end of the defrosting operation is higher than in the case of full opening. As a result, the higher the condensation temperature, the faster the frost is removed. When the opening degree of the expansion valve 400 is reduced, the time when the outdoor heat exchanger 500 has removed the frost has elapsed. The end of the defrosting operation may be determined.

  For this reason, if frost formation of the outdoor heat exchanger 500 is removed and the defrosting operation is continued in a state where the frost that is the heat exchange target of the refrigerant flowing in the outdoor heat exchanger 500 is removed, the frost is increased from the start of melting. The condensation pressure of the outdoor heat exchanger 500 increases with the passage of time, which places a burden on the compressor 100.

  In this embodiment, in order to solve such a problem, when the opening degree of the expansion valve 400 is fully open, the condensation temperature of the outdoor heat exchanger 500 at the time of determining the end of the defrosting operation may be too high. Therefore, the outlet temperature To of the outdoor heat exchanger 500 is set to a temperature having a sufficient margin, for example, 15 ° C. as a temperature at which frost attached to the outdoor heat exchanger 500 disappears.

  On the other hand, when the opening degree of the expansion valve 400 is reduced, the condensation temperature of the outdoor heat exchanger 500 at the time of determining the end of the defrosting operation becomes high, so the outlet temperature To of the outdoor heat exchanger 500 is set to the outdoor temperature. The temperature is set to a temperature at which the frost adhered to the heat exchanger 500 disappears and the condensation temperature of the outdoor heat exchanger 500 at the time of determining the completion of the defrosting operation is lowered, for example, 10 ° C.

  Therefore, in the heat pump device according to the present embodiment, when the first opening (for example, the number of expansion valve pulses is 150 pulses), the outlet temperature of the outdoor heat exchanger 500 is equal to or higher than a predetermined first temperature (for example, 10 ° C.). When the defrosting operation is completed and the second opening degree (for example, the number of expansion valve pulses is 480 pulses), the outlet temperature of the outdoor heat exchanger 500 is higher than the first temperature (for example, 10 ° C.). The defrosting operation is ended when the second temperature (for example, 15 ° C.) or higher is reached.

  Thereby, when the opening temperature of the expansion valve 400 is fully opened, the outlet temperature of the outdoor heat exchanger 500 which is a condition for determining the end of the defrosting operation when the opening degree of the expansion valve 400 is reduced during the defrosting operation. By setting it lower than that, the end of the defrosting operation is advanced in time, and the useless defrosting operation in the state where the frost formation of the outdoor heat exchanger 500 is removed is eliminated. The rise in the condensation pressure of the inside outdoor heat exchanger 500 can be suppressed, the compressor 100 is not burdened, and the reliability of the heat pump device can be maintained.

DESCRIPTION OF SYMBOLS 100 Compressor 200 Four-way valve 300 Refrigerant-water heat exchanger 400 Expansion valve 500 Outdoor heat exchanger 600 Circulation pump 700 Heating device 800 Outdoor fan 900 Controller A Heat pump cycle Sp Compressor discharge pressure sensor St1 Refrigerant-water heat exchanger temperature sensor St2 outdoor heat exchanger temperature sensor

Claims (4)

  A heat pump device having a heat pump cycle comprising a compressor, a four-way valve, a refrigerant-water heat exchanger, an expansion valve, and an outdoor heat exchanger, and at the time of defrosting operation for removing frost formation on the outdoor heat exchanger, The four-way valve is switched to reverse the direction of refrigerant flow during heating operation and to adjust the opening of the expansion valve based on detection information correlated with the temperature of hot water flowing through the refrigerant-water heat exchanger. A heat pump device characterized by that.   The detection information is a condensing temperature of the refrigerant-water heat exchanger, and the opening of the expansion valve is a first opening when the condensing temperature is equal to or higher than a predetermined temperature, and a second opening when the condensing temperature is lower than the predetermined temperature. The heat pump device according to claim 1, wherein the heat pump device is smaller than the opening.   The detection information is the discharge pressure of the compressor, and the opening of the expansion valve is smaller than the first opening when the discharge pressure is equal to or higher than a predetermined pressure and smaller than the second opening when the discharge pressure is lower than the predetermined pressure. The heat pump device according to claim 1, wherein   In the case of the first opening, the defrosting operation is terminated when the outlet temperature of the outdoor heat exchanger reaches a predetermined first temperature or higher, and in the case of the second opening, the outdoor heat is The heat pump device according to claim 2 or 3, wherein the defrosting operation is terminated when an outlet temperature of the exchanger reaches a predetermined second temperature higher than the first temperature.

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