JP6508066B2 - Water heater - Google Patents

Description

  The present invention relates to a heat pump type water heater.

  As a compressor used for this kind of water heater, there is a compressor described in Patent Document 1. The compressor described in Patent Document 1 is a scroll compressor, and includes a compression mechanism unit, a motor unit, and a housing. The compression mechanism unit is a positive displacement compressor that sucks, compresses and discharges the refrigerant to be compressed. The motor unit drives the compression mechanism unit. The housing accommodates the compression mechanism portion and the motor portion inside.

  The compressor includes a drive shaft for transmitting rotational power from the motor unit to the compression mechanism unit. Both ends of the drive shaft are rotatably supported by bearings. The bearing is constituted by a slide bearing. An oil supply passage for supplying lubricating oil to a sliding portion between an outer surface of the drive shaft and the bearing is formed inside the drive shaft.

JP, 2013-32729, A

  By the way, in the hot water supply apparatus, it is conceivable to change its heating capacity according to the situation. Specifically, when the rotational speed of the drive shaft of the compressor is changed, the flow rate of the refrigerant circulating in the heat pump cycle is changed, so that it is possible to change the heating capacity of the water heater. On the other hand, when the rotational speed of the drive shaft of the compressor is changed, the pressure of the refrigerant discharged from the compressor changes, so the difference between the pressure of the low pressure refrigerant on the upstream side of the compressor and the pressure of the high pressure refrigerant on the downstream side The pressure changes. Such a change in differential pressure between the compressor and the compressor causes a change in the refrigerant compression load acting on the bearing. If the oil film parameters of the lubricating oil interposed between the outer surface of the drive shaft and the bearing decrease due to changes in the rotational speed of the drive shaft and the refrigerant compression load, the drive shaft and the bearing may be in metal contact and may be worn out is there. The oil film parameter is an index that quantifies the lubricating state of the lubricating oil.

  The present invention has been made in view of these circumstances, and it is an object of the present invention to provide a hot water supply apparatus capable of more appropriately maintaining a lubricating state between a drive shaft of a compressor and a bearing. .

  In order to solve the said subject, a hot-water supply apparatus (10) is provided with a heat pump cycle (50) and a control part (59). The heat pump cycle is cooled by a compressor (51) that compresses and discharges low-pressure refrigerant, a high-pressure side heat exchanger (52) that exchanges the high-pressure refrigerant discharged from the compressor with water for hot water supply, and a high-pressure side heat exchanger The expansion unit (53) decompresses and expands the refrigerant, and the low pressure side heat exchanger (54) generates the low pressure refrigerant by evaporating the refrigerant decompressed and expanded through the expansion unit. The control unit controls the heat pump cycle. The compressor includes a compression mechanism (510) that compresses low-pressure refrigerant to generate high-pressure refrigerant, a motor (520) that drives the compression mechanism, and a drive shaft that transmits rotational power from the motor to the compression mechanism. (523) and bearings (524, 525) rotatably supporting the drive shaft. When the load acting on the bearing according to the differential pressure between the high-pressure refrigerant and the low-pressure refrigerant is the refrigerant compression load, the control unit rotates the drive shaft according to the switching mode of the heating capacity when switching the heating capacity of the heat pump cycle. Change the adjustment order of speed and refrigerant compression load.

  According to this configuration, when switching the heating capacity of the heat pump cycle, adjustment of the rotational speed of the drive shaft and the refrigerant compression load so that the oil film parameter of the lubricating oil interposed between the drive shaft and the bearing does not become smaller than the lower limit. By changing the order, it is possible to maintain the lubrication condition of the lubricating oil more appropriately.

  In addition, the code | symbol in the parentheses as described in said means and a claim is an example which shows a correspondence with the specific means as described in embodiment mentioned later.

  According to the present invention, the lubrication state between the drive shaft of the compressor and the bearing can be maintained more properly.

It is a block diagram which shows schematic structure of the hot-water supply apparatus of 1st Embodiment. It is sectional drawing which shows the cross-section of the compressor of 1st Embodiment. It is a flowchart which shows the procedure of the process performed by the hot-water supply apparatus of 1st Embodiment. It is a flowchart which shows the procedure of the process performed by the hot-water supply apparatus of 2nd Embodiment. It is a block diagram which shows the electric constitution of the heat pump cycle of 2nd Embodiment.

Hereinafter, an embodiment of a hot water supply apparatus will be described.
As shown in FIG. 1, the water heating apparatus 10 of the present embodiment includes a heat pump unit 20, a tank unit 30, and an operation unit 40. The hot water supply apparatus 10 is, for example, an apparatus that generates hot water for hot water supply from tap water in a house and supplies hot water to a hot water supply terminal such as a shower, a bath, a bath tub, or the like.

  The heat pump unit 20 includes a pump 21 and a heat pump cycle 50.

  The heat pump cycle 50 includes a compressor 51, a high pressure side heat exchanger 52, an expansion valve 53, a low pressure side heat exchanger 54, and a blower 55.

  The compressor 51 is a device that compresses and discharges the low pressure refrigerant supplied from the low pressure side heat exchanger 54. The high pressure refrigerant compressed by the compressor 51 is supplied to the high pressure heat exchanger 52.

  The high pressure side heat exchanger 52 integrally has a refrigerant flow channel 52a and a hot water supply water flow channel 52b. The high pressure refrigerant supplied from the compressor 51 is flowing through the refrigerant flow path 52a. The hot water supply water flow path 52 b is connected to the upper and lower portions of the tank 31 of the tank unit 30 via the heat storage circuit 22. Hot water supply water supplied from the lower part of the tank 31 through the heat storage circuit 22 flows in the hot water supply water flow path 52 b. The high pressure side heat exchanger 52 performs heat exchange between the high pressure refrigerant supplied from the compressor 51 and the hot water supply water supplied from the tank 31, and heats the hot water supply water by the heat radiation function to generate high temperature hot water. Supply the hot water to the top of the tank 31.

  The pump 21 is provided in the heat storage circuit 22. The pump 21 has a hot water circulation function of returning the water stored in the lower part of the tank 31 to the upper part of the tank 31 via the high-pressure heat exchanger 52.

  The expansion valve 53 generates a low pressure refrigerant by decompressing and expanding the refrigerant cooled by the high pressure side heat exchanger 52. The low pressure refrigerant generated by the expansion valve 53 is supplied to the low pressure side heat exchanger 54. In the present embodiment, the expansion valve 53 corresponds to an expansion portion.

  The low pressure side heat exchanger 54 absorbs heat from the air blown from the blower 55, and generates a low pressure refrigerant by evaporating the refrigerant decompressed and expanded through the expansion valve 53. The air blown from the blower 55 to the low pressure side heat exchanger 54 is air outside the house. The air outside the house will be abbreviated as "outside air" below. The low pressure refrigerant generated by the low pressure side heat exchanger 54 is supplied to the compressor 51.

  The heat pump cycle 50 includes an outside air temperature sensor 56, a pressure sensor 57, a boiling temperature thermistor 58, and a heat pump ECU (Electronic Control Unit) 59. In the present embodiment, the heat pump ECU 59 corresponds to a control unit.

  The outside air temperature sensor 56 detects the temperature of the outside air supplied from the blower 55 to the low pressure side heat exchanger 54. The pressure sensor 57 detects the pressure of the high pressure refrigerant discharged from the compressor 51. The boiling temperature thermistor 58 detects the temperature of hot water supplied from the high pressure side heat exchanger 52 to the tank 31. The output signals of the sensors 56 to 58 are taken into the heat pump ECU 59.

  The heat pump ECU 59 detects the temperature of the outside air, the pressure of the high pressure refrigerant, and the temperature of the hot water supplied from the high pressure heat exchanger 52 to the tank 31 based on the output signals of the sensors 56 to 58. The heat pump ECU 59 is communicably connected to the hot water storage ECU 38 of the tank unit 30. The hot water storage ECU 38 transmits the target temperature of the hot water supply water supplied to the tank 31 to the heat pump ECU 59. The heat pump ECU 59 controls the compressor 51, the blower 55, the pump 21 and the like so that the temperature of the hot water supply water detected by the boiling temperature thermistor 58 becomes the target temperature transmitted from the hot water storage ECU 38.

  The tank unit 30 includes a tank 31, water supply pipes 32 and 33, a hot water supply pipe 34, and a mixing valve 35.

  The water supply pipe 32 is connected to the lower part of the tank 31. The water supply pipe 32 supplies tap water to the lower part of the tank 31.

  The hot water supply pipe 34 supplies the hot water supply water stored in the upper part of the tank 31 to the hot water supply terminal. A water supply pipe 33 branched from a front portion of the water supply pipe 32 leading to the tank 31 joins the hot water supply pipe 34. A mixing valve 35 is provided at the junction of the hot water supply pipe 34 and the water supply pipe 33. The mixing valve 35 changes the mixing ratio of the hot water supplied from the upper part of the tank 31 through the hot water supply pipe 34 and the water supplied through the water supply pipe 33 by changing the opening degree. Thereby, the temperature of the hot water for hot water discharge to the hot water supply terminal can be adjusted.

  The tank unit 30 includes a tank thermistor 36, a hot water temperature thermistor 37, and a hot water storage ECU 38.

  A plurality of tank thermistors 36 are provided in the tank 31. The tank thermistor 36 detects the temperature of the hot water supply stored in the tank 31. The hot water temperature thermistor 37 is provided on the outlet side of the mixing valve 35, and detects the temperature of the hot water supply water mixed by the mixing valve 35, that is, the temperature of the hot water supply water supplied to the hot water supply terminal. The output signals of the thermistors 36 and 37 are taken into the hot water storage ECU 38.

  The hot water storage ECU 38 also receives an output signal of the operation unit 40. The operation unit 40 is operated by the resident. The operation unit 40 can perform various operations of the hot water supply apparatus 10, such as setting of the temperature of the hot water supply water and the bathing operation of the bathtub.

  The hot water storage ECU 38 detects various state quantities of the tank 31 based on the output signal of the tank thermistor 36. For example, the hot water storage ECU 38 detects the water temperature and the amount of hot water in the tank 31 at each water level based on the temperature information of the tank 31 obtained from the output signal of the tank thermistor 36. Further, the hot water storage ECU 38 calculates the amount of hot water stored in the tank 31 by detecting the temperature and the amount of hot water of the tank 31. Furthermore, the hot water storage ECU 38 mixes the hot water for boiling after the upper part of the tank 31 and the hot water for boiling before the lower part in the tank 31 based on the temperature information of the tank 31 obtained from the output signal of the tank thermistor 36. Boundary position is detected.

  The hot water storage ECU 38 is based on various state quantities of the tank 31 obtained based on the output signal of the tank thermistor 36, the temperature of hot water supply obtained based on the output signal of the hot water temperature thermistor 37, and operation information of the operation unit 40, etc. The operation of the tank unit 30 and the heat pump unit 20 is controlled. For example, the hot water storage ECU 38 obtains the set temperature of the hot water supply water based on the operation information of the operation unit 40, and adjusts the degree of opening of the mixing valve 35 so that the temperature of the hot water supply water detected by the hot water temperature thermistor 37 becomes the set temperature. Do.

  The hot water storage ECU 38 is communicably connected to the power management system 60 of the house. The power management system 60 is a system that comprehensively manages the power consumption and the power generation amount of a house. The power management system 60 instructs the hot water storage ECU 38 to perform a boiling operation, for example, in an inexpensive late-night time zone of a set charge. At this time, the hot water storage ECU 38 heats the hot water supply water in the tank 31 by instructing the heat pump ECU 59 to perform a boiling operation and transmitting the target temperature of the hot water supply water supplied from the heat pump unit 20 to the tank 31 to the heat pump ECU 59. Do. Note that the power management system 60 instructs the hot water storage ECU 38 to perform a boiling operation when the amount of heat stored in the hot water in the tank 31 is insufficient even in a time zone other than the midnight time zone.

  Furthermore, the power management system 60 instructs the hot water storage ECU 38 to change the heating capacity of the heat pump unit 20 according to the power consumption of the house. For example, the power management system 60 may instruct the hot water storage ECU 38 to reduce the power consumption when there is a possibility that a power shortage may occur due to the increase in the power consumption of the house. In this case, the hot water storage ECU 38 sends a heating capacity change request for reducing the heating capacity of the heat pump cycle 50 to the heat pump ECU 59. The heating capacity change request includes the required heating capacity value. The unit of heating capacity is "W" or "J / S". When the heat storage ECU 38 receives a request for changing the heating capacity from the hot water storage ECU 38, the heat pump ECU 59 compares the required value of the heating capacity contained therein with the current heating capacity, and determines that the current heating capacity is larger than the required value. By reducing the rotational speed of 51, the heating capacity of the heat pump cycle 50 is reduced.

  On the other hand, when the power management system 60 instructs the hot water storage ECU 38 to perform the boiling operation, the power storage can be increased to the hot water storage ECU 38 that the power consumption may be increased if there is room in the household power. May be instructed. In this case, the hot water storage ECU 38 sends a heating capacity change request to the heat pump ECU 59 to increase the heating capacity of the heat pump cycle 50. When the heat storage ECU 38 requests heating capacity change from the hot water storage ECU 38, the heat pump ECU 59 compares the heating capacity request value contained therein with the current heating capacity and determines that the current heating capacity is smaller than the required value. By increasing the rotational speed of 51, the heating capacity of the heat pump cycle 50 is increased.

Next, the structure of the compressor 51 will be described.
As shown in FIG. 2, the compressor 51 includes a compression mechanism unit 510, a motor unit 520, a housing 530, and an oil separator 540. The compression mechanism unit 510 sucks, compresses and discharges the refrigerant to be compressed. The motor unit 520 drives the compression mechanism unit 510. The housing 530 accommodates the compression mechanism portion 510 and the motor portion 520. The oil separator 540 is disposed outside the housing 530 and separates the lubricating oil from the high pressure refrigerant compressed by the compression mechanism unit 510. The compressor 51 is a positive displacement compressor that compresses the refrigerant by a change in volume of the compression mechanism unit 510.

  The compressor 51 has a drive shaft 523 for transmitting rotational power from the motor unit 520 to the compression mechanism unit 510. The compressor 51 has a so-called vertical type configuration in which the drive shaft 523 extends in the vertical direction, and the compression mechanism unit 510 and the motor unit 520 are arranged in the vertical direction.

  The housing 530 is formed with a suction port 531 and a refrigerant outlet (not shown). The suction port 531 allows the low pressure refrigerant supplied from the low pressure side heat exchanger 54 to flow into the compression mechanism section 510. The refrigerant outlet causes the high pressure refrigerant discharged from the compression mechanism unit 510 to flow out to the oil separator 540 side.

  The motor unit 520 includes a coil stator 521 forming a stator and a rotor 522 forming a rotor. A drive shaft 523 is press-fitted and fixed to an axial center hole of the rotor 522. Accordingly, when a rotating magnetic field is generated by the power supply to the coil stator 521, the rotor 522 and the drive shaft 523 rotate integrally.

The drive shaft 523 is formed in a substantially cylindrical shape, and both ends thereof are rotatably supported by the first bearing 524 and the second bearing 525. The first bearing 524 and the second bearing 525 are slide bearings. Inside the drive shaft 523 is formed an oil supply passage 523a for supplying lubricating oil to the sliding portion between the outer surface of the drive shaft 523 and the bearings 524 and 525. The outer periphery of the first bearing 524 is fixed to the housing 530. The first bearing 524 supports the lower end portion of the drive shaft 523. The second bearing 525 is fixed to the housing 530 via the interposing member 526 and supports the upper end side of the drive shaft 523.

  The compression mechanism unit 510 is a scroll-type compression mechanism including a movable scroll 511 having tooth portions formed in a spiral shape and a fixed scroll 512. The movable scroll 511 is disposed below the housing 530 in the vertical direction. The fixed scroll 512 is disposed below the movable scroll 511 in the vertical direction. The outer periphery of the fixed scroll 512 is fixed to the housing 530.

  At the lower end portion of the drive shaft 523, an eccentric portion 523 b eccentric to the rotation center of the drive shaft 523 is formed. The eccentric portion 523 b is inserted into a cylindrical boss 513 formed on the upper surface of the movable scroll 511 in the vertical direction. In the compressor 51, when the drive shaft 523 rotates, the movable scroll 511 revolves (rocks) around the center of rotation of the drive shaft 523 without rotating around the eccentric portion 523b.

  The movable scroll 511 is formed with a spiral tooth portion 511 a protruding toward the fixed scroll 512 side. The fixed scroll 512 is formed with a spiral tooth portion 512 a that protrudes toward the movable scroll 511 and that meshes with the tooth portion 511 a of the movable scroll 511. A plurality of compression chambers 515 formed in a crescent shape when viewed from the rotation axis direction are formed by meshing the tooth portions 511a and 512a of both the scrolls 511 and 512 with each other and contacting at a plurality of places. In FIG. 2, in order to clarify the illustration, only one compression chamber of the plurality of compression chambers 515 is denoted by a reference numeral, and the reference numerals for the other compression chambers are omitted. The compression chamber 515 moves while reducing the volume from the outer peripheral side to the central side as the movable scroll 511 revolves. The suction port 531 is in communication with the compression chamber 515 positioned on the outermost side.

  At a central portion of the fixed scroll 512, a discharge hole 512b is formed to which the refrigerant compressed in the compression chamber 515 is discharged. A discharge chamber 512c communicating with the discharge hole 512b is formed below the discharge hole 512b. In the discharge chamber 512c, a reed valve (not shown) forming a check valve for preventing the backflow of the refrigerant from the discharge chamber 512c side to the compression chamber 515 side and a stopper 516 for restricting the maximum opening degree of the reed valve are arranged There is.

  Inside the housing 530, a refrigerant passage (not shown) for guiding the refrigerant from the discharge chamber 512c to a refrigerant outlet formed in the housing 530 is formed. A refrigerant inlet 541 of the oil separator 540 is connected to the refrigerant outlet. The oil separator 540 swirls the refrigerant pressurized by the compression mechanism unit 510 in a space formed therein, and separates the gas phase refrigerant and the lubricating oil by the action of centrifugal force.

  The high pressure gas phase refrigerant separated by the oil separator 540 flows out from the discharge port 542 formed on the upper side of the oil separator 540 to the high pressure side heat exchanger 52. On the other hand, the lubricating oil separated by the oil separator 540 is stored in the lower part of the oil separator 540, and the compression mechanism 510 in the housing 530, the drive shaft 523 and the bearing 524 via the oil passage 517, It is supplied to the sliding portion with 525 and the like.

  By the way, in such a compressor 51, when the rotational speed of the drive shaft 523 is changed to change the heating capacity of the heat pump cycle 50, the pressure of the high pressure refrigerant discharged from the compressor 51 changes. Therefore, the differential pressure between the pressure of the low pressure refrigerant on the upstream side of the compressor 51 and the pressure of the high pressure refrigerant on the downstream side changes. Such a change in differential pressure of the compressor 51 causes a change in the refrigerant compression load acting on the bearings 524, 525. When the oil film parameters of the lubricating oil interposed between the outer surface of the drive shaft 523 and the bearings 524 and 525 decrease due to the change of the rotational speed of the drive shaft 523 and the refrigerant compression load, the drive shaft 523 and the bearings 524 and 525 are metal They can come in contact and cause wear.

  Therefore, in the present embodiment, when switching the heating capacity of the heat pump cycle 50, the rotational speed of the drive shaft 523 of the compressor 51 and the adjustment order of the refrigerant compression load are changed according to the switching mode of the heating capacity. There is. The contents will be described in detail below. Hereinafter, for convenience, the rotational speed of the drive shaft 523 of the compressor 51 is also referred to as “the rotational speed of the compressor 51”.

First, the following equation f1 is established among the oil film parameter 潤滑 of the lubricating oil, the rotational speed V of the drive shaft 523 of the compressor 51, the refrigerant compression load F, and the viscosity μ of the lubricating oil.
Λ∝V × μ / F (f1)
Here, as compared with the rotation speed V of the drive shaft 523, the refrigerant compression load F is a small value.

  As apparent from the formula f1, when it is assumed that the viscosity μ of the lubricating oil is a constant value, when reducing both the refrigerant compression load F and the rotational speed V of the compressor 51, the rotational speed V of the compressor 51 If it is reduced earlier, the oil film parameter Λ will be reduced. On the other hand, if the refrigerant compression load F is reduced first, the oil film parameter Λ will not be reduced. Therefore, in the case of reducing the heating capacity of the heat pump cycle 50, if the rotational speed V of the compressor 51 is reduced after reducing the refrigerant compression load F, the oil film parameter Λ is the drive shaft 523 and the bearings 524, 525. And the lower limit value of the oil film parameter that can maintain the lubricating state of the lubricating oil interposed therebetween.

  On the other hand, in the case where both the refrigerant compression load F and the rotational speed V of the compressor 51 are increased, if the refrigerant compression load F is increased first, the oil film parameter 一時 temporarily decreases. On the other hand, when the rotational speed V of the compressor 51 is increased first, the oil film parameter Λ does not decrease. Therefore, if the heating capacity of the heat pump cycle 50 is increased, if the refrigerant compression load F is increased after the rotational speed V of the compressor 51 is increased, the oil film parameter Λ becomes smaller than the lower limit value. It can be suppressed.

  Next, the change procedure of the heating capacity performed by heat pump ECU59 based on the above principle is demonstrated.

  The heat pump ECU 59 executes the process shown in FIG. 3 when there is a heating capacity change request from the hot water storage ECU 38. As shown in FIG. 3, the heat pump ECU 59 first determines whether the current heating capacity Q1 is larger than the heating capacity required value Q2 as the process of step S10. If the heat pump ECU 59 makes an affirmative determination in the process of step S10, that is, if the current heating capacity Q1 is larger than the required value Q2 of the heating capacity, the refrigerant compression load F is first applied as the process of step S11. Lower than. Specifically, the heat pump ECU 59 reduces the refrigerant compression load F by making the opening degree of the expansion valve 53 larger than the current opening degree. Thereafter, the heat pump ECU 59 reduces the rotational speed V of the compressor 51 to be lower than the current rotational speed as the process of step S12.

  If the heat pump ECU 59 determines in the negative in the process of step S10, that is, if the current heating capacity Q1 is equal to or less than the required value Q2 of the heating capacity, the rotational speed V of the compressor 51 is first processed as the process of step S13. To increase the current rotational speed. Thereafter, as the process of step S14, the heat pump ECU 59 raises the refrigerant compression load F higher than the current load. Specifically, the heat pump ECU 59 raises the refrigerant compression load F by making the opening degree of the expansion valve 53 larger than the current opening degree.

  According to the hot water supply apparatus 10 of the present embodiment described above, it is possible to obtain the actions and effects shown in the following (1) and (2).

  (1) When switching the heating capacity of the heat pump cycle 50, the heat pump ECU 59 changes the adjustment order of the rotational speed V of the compressor 51 and the refrigerant compression load F according to the switching mode of the heating capacity. Specifically, when reducing the heating capacity of the heat pump cycle 50 to be lower than the current heating capacity Q1, the heat pump ECU 59 reduces the rotational speed V of the compressor 51 after reducing the refrigerant compression load F. Further, when increasing the heating capacity of the heat pump cycle 50 more than the current heating capacity Q1, the heat pump ECU 59 increases the rotational speed V of the compressor 51 and then increases the refrigerant compression load F. As a result, the oil film parameter of the lubricating oil interposed between the drive shaft 523 and the bearings 524 and 525 can be suppressed to be smaller than the lower limit value, so that the lubricating state of the lubricating oil can be maintained more appropriately.

  (2) The heat pump ECU 59 adjusts the refrigerant compression load F of the compressor 51 by adjusting the opening degree of the expansion valve 53. Specifically, the heat pump ECU 59 makes the refrigerant compression load F of the compressor 51 lower than the current load by making the opening degree of the expansion valve 53 larger than the current opening degree. Further, the heat pump ECU 59 makes the refrigerant compression load F of the compressor 51 higher than the current load by making the opening degree of the expansion valve 53 smaller than the current opening degree. Thus, the refrigerant compression load F of the compressor 51 can be easily adjusted.

Second Embodiment
Next, a second embodiment of the water heating apparatus 10 will be described. Hereinafter, differences from the first embodiment will be mainly described.

  The heat pump ECU 59 according to the present embodiment executes the process shown in FIG. 4 instead of the process shown in FIG. 3. That is, the heat pump ECU 59 first calculates the oil film parameter Λ of the lubricating oil interposed between the drive shaft 523 and the bearings 524 and 525 based on the above formula f1 as the process of step S20.

  Specifically, as shown in FIG. 5, the heat pump ECU 59 includes a temperature acquisition unit 590, a first pressure acquisition unit 591 and a second pressure acquisition unit 592.

  The temperature acquisition unit 590 is a part that acquires the temperature of the lubricating oil. The temperature acquisition unit 590 of the present embodiment uses the detected temperature of the outside air temperature sensor 56 as the temperature of the lubricating oil.

  The first pressure acquisition unit 591 is a part that acquires the pressure of the high-pressure refrigerant of the compressor 51. The first pressure acquisition unit of the present embodiment uses the pressure detected by the pressure sensor 57 as the pressure of the high pressure refrigerant of the compressor 51.

  The second pressure acquisition unit 592 is a part that acquires the pressure of the low pressure refrigerant of the compressor 51. Specifically, the second pressure acquisition unit 592 has a map or an arithmetic expression indicating the relationship between the pressure of the low-pressure refrigerant of the compressor 51 and the temperature of the outside air. The second pressure acquisition unit 592 estimates the pressure of the low-pressure refrigerant of the compressor 51 from the temperature detected by the outside air temperature sensor 56 using these maps, arithmetic expressions, and the like.

  The heat pump ECU 59 has a map, an arithmetic expression, and the like that indicate the relationship between the viscosity of the lubricating oil and the temperature of the lubricating oil. The heat pump ECU 59 calculates the viscosity μ of the lubricating oil from the temperature of the lubricating oil detected by the temperature acquisition unit 590 based on a map, an arithmetic expression, and the like.

  The heat pump ECU 59 calculates the refrigerant compression load F based on the differential pressure between the pressure of the high pressure refrigerant acquired by the first pressure acquisition unit 591 and the pressure of the low pressure refrigerant acquired by the second pressure acquisition unit 592.

  The heat pump ECU 59 calculates “V × μ / F” from the current rotational speed V of the compressor 51, the viscosity μ of the lubricating oil, and the refrigerant compression load F, and multiplies the calculated value by a predetermined proportional constant. Determine the oil film parameter 潤滑 of the lubricating oil.

  As shown in FIG. 4, the heat pump ECU 59 calculates the difference value ΔΛ (= Λ−Λmin) between the calculated value of the oil film parameter と and the lower limit value Λmin of the oil film parameter as the process of step S21 following the process of step S20. Do. Next, the heat pump ECU 59 sets the adjustment amount of the refrigerant compression load F and the adjustment amount of the rotation speed V of the compressor 51 based on the difference value ΔΛ as the process of step S22.

  For example, when the difference value ΔΛ is larger than the predetermined value, the heat pump ECU 59 determines that there is a margin in the lubricating state of the lubricating oil, and the adjustment amount of the refrigerant compression load F and the adjustment amount of the rotation speed V of the compressor 51 Set to the normal value. The predetermined value is set in advance by experiment or the like so that it can be determined whether or not there is a margin in the lubricating state of the lubricating oil.

  On the other hand, when the difference value ΔΛ is less than the predetermined value, the heat pump ECU 59 determines that there is no margin in the lubricating state of the lubricating oil, and the adjustment amount of the refrigerant compression load F and the adjustment amount of the rotational speed V of the compressor 51 Set to a value smaller than the normal value.

  The heat pump ECU 59 executes the processes of steps S10 to S14 following step S21. When the heat pump ECU 59 executes the processing of steps S11 to S14, the refrigerant compression load F and the compressor are based on the adjustment amount of the refrigerant compression load F set in step S21 and the adjustment amount of the rotation speed V of the compressor 51. Change the rotational speed V of 51.

  According to the hot water supply apparatus 10 of the present embodiment described above, it is possible to obtain the operation and effects shown in the following (3).

  (3) The heat pump ECU 59 adjusts the refrigerant compression load F and the rotational speed V of the compressor 51 based on the calculated value of the oil film parameter Λ. As a result, the refrigerant compression load F and the rotational speed V of the compressor 51 can be changed more appropriately in accordance with the actual oil film parameter 、, so that the lubrication state of the lubricating oil can be more appropriately maintained.

Other Embodiments
In addition, each embodiment can also be implemented in the following modes.
-Temperature acquisition part 590 of a 2nd embodiment may acquire the temperature of lubricating oil based on the output signal of the sensor which detects the temperature of lubricating oil directly.

  The second pressure acquisition unit 592 according to the second embodiment may acquire the pressure of the low pressure refrigerant of the compressor 51 based on the output signal of a sensor that directly detects the pressure of the low pressure refrigerant of the compressor 51. .

  The method of changing the refrigerant compression load F of the compressor 51 can be changed as appropriate. For example, the heat pump ECU 59 may change the refrigerant compression load F of the compressor 51 by changing the rotational speed of the fan of the blower 55. Specifically, the heat pump ECU 59 reduces the refrigerant compression load F of the compressor 51 by increasing the rotational speed of the fan of the blower 55 more than the current rotational speed. The heat pump ECU 59 also raises the refrigerant compression load F of the compressor 51 by reducing the rotational speed of the fan of the blower 55 than the current rotational speed.

  The configuration of each embodiment can also be employed in the heat pump cycle 50 in which an ejector is used instead of the expansion valve 53. The ejector is a nozzle that decompresses the refrigerant condensed by the high pressure side heat exchanger 52 after being compressed to a high pressure by the compressor 51, a suction unit that sucks the low pressure refrigerant flowing out of the low pressure side heat exchanger 54, and a nozzle And a diffuser for mixing and pressurizing the refrigerant ejected from the nozzle and the refrigerant drawn in the suction part. In such a heat pump cycle 50, the refrigerant compression load F of the compressor 51 can be changed by adjusting the opening degree of the ejector.

  The means and / or functions provided by the hot water storage ECU 38 and the heat pump ECU 59 can be provided by software stored in a substantial storage device and a computer that executes it, only software, only hardware, or a combination thereof. . For example, when the hot water storage ECU 38 and the heat pump ECU 59 are provided by an electronic circuit that is hardware, it can be provided by a digital circuit or analog circuit including a number of logic circuits.

  The present invention is not limited to the above specific example. That is, to the above specific examples, those skilled in the art may appropriately modify the design as long as the features of the present invention are included in the scope of the present invention. For example, each element included in each specific example described above and its arrangement, conditions, and the like are not limited to those illustrated, and can be appropriately changed. Moreover, each element with which the above-mentioned embodiment is equipped can be combined as much as technically possible, and what combined these is also included in the scope of the present invention as long as the feature of the present invention is included.

10: Water heater 50: Heat pump cycle 51: Compressor 52: High-pressure side heat exchanger 53: Expansion valve (expansion part)
54: low pressure side heat exchanger 55: air blower 59: heat pump ECU (control unit)
510: compression mechanism unit 520: motor unit 523: drive shaft 524, 525: bearing 590: temperature acquisition unit 591: first pressure acquisition unit 592: second pressure acquisition unit

Claims (6)

A compressor (51) which compresses and discharges low-pressure refrigerant, a high-pressure side heat exchanger (52) which exchanges the high-pressure refrigerant discharged from the compressor with water for hot water supply, a refrigerant cooled by the high-pressure side heat exchanger A heat pump cycle (50) comprising: an expansion part (53) for reducing and expanding the pressure, and a low pressure side heat exchanger (54) for generating the low pressure refrigerant by evaporating the refrigerant reduced and expanded through the expansion part;
A controller (59) for controlling the heat pump cycle;
The compressor rotates a compression mechanism (510) that compresses the low-pressure refrigerant to generate the high-pressure refrigerant, a motor (520) that drives the compression mechanism, and rotation from the motor to the compression mechanism. A drive shaft (523) for transmitting power, and bearings (524, 525) for rotatably supporting the drive shaft,
When a load acting on the bearing according to a differential pressure between the high pressure refrigerant and the low pressure refrigerant is a refrigerant compression load:
The water heating apparatus changes the rotational speed of the drive shaft and the adjustment order of the refrigerant compression load according to a switching mode of the heating capacity when switching the heating capacity of the heat pump cycle. In the case where the heating capacity of the heat pump cycle is lower than the current heating capacity, the control unit reduces the rotational speed of the drive shaft after reducing the refrigerant compression load. . When the heating capacity of the heat pump cycle is made higher than the current heating capacity, the control unit raises the compression load of the refrigerant after raising the rotational speed of the drive shaft. . The control unit
A first pressure acquisition unit (591) for acquiring the pressure of the high-pressure refrigerant;
A second pressure acquisition unit (592) for acquiring the pressure of the low pressure refrigerant;
A temperature acquisition unit (590) for acquiring the temperature of lubricating oil interposed between the drive shaft and the bearing;
The refrigerant compression load is calculated based on the pressure of the high-pressure refrigerant and the pressure of the low-pressure refrigerant,
The viscosity of the lubricating oil is calculated based on the temperature of the lubricating oil,
The oil film parameter of the lubricating oil is calculated based on the rotational speed of the drive shaft, the refrigerant compression load, and the viscosity of the lubricating oil,
The hot water supply device according to any one of claims 1 to 3, wherein the rotational speed of the drive shaft and the refrigerant compression load are adjusted based on the oil film parameter. The hot water supply device according to any one of claims 1 to 4, wherein the control unit adjusts the refrigerant compression load by adjusting an opening degree of the expansion unit. It further comprises a blower (55) for blowing air to the low pressure side heat exchanger,
The hot water supply device according to any one of claims 1 to 4, wherein the control unit adjusts the refrigerant compression load by adjusting a rotational speed of a fan of the blower.

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