JP2017122545A - Water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water heater which can suitably maintain a lubrication state between a drive shaft and a bearing of a compressor.SOLUTION: A water heater 10 comprises a heat pump cycle 50 and a heat pump ECU 59. The heat pump cycle 50 has a compressor 51, a high-pressure side heat exchanger 52, an expansion valve 53, and a low-pressure side heat exchanger 54. The heat pump ECU 59 controls the heat pump cycle 50. The compressor 51 has a compression mechanism part which creates a high-pressure refrigerant by compressing a low-pressure refrigerant, an electric motor part which drives the compression mechanism part, a drive shaft for transmitting rotation power from the electric motor part to the compression mechanism part, and a bearing for supporting the drive shaft. When a load acting on the bearing according to a pressure difference between the high-pressure refrigerant and the low-pressure refrigerant is set as a refrigerant compression load, the heat pump ECU 59 changes an adjustment order of a rotational speed of the drive shaft and the refrigerant compression load according to a switching form of a heating capacity when switching the heating capacity of the heat pump cycle 50.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat pump hot water supply apparatus.

  As a compressor used in this type of hot water supply apparatus, there is a compressor described in Patent Document 1. The compressor described in Patent Document 1 is a scroll-type compressor, and includes a compression mechanism section, an electric motor section, and a housing. The compression mechanism unit is a positive displacement compressor that sucks, compresses and discharges a refrigerant to be compressed. The electric motor unit drives the compression mechanism unit. The housing accommodates the compression mechanism portion and the electric motor portion inside.

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

JP 2013-32729 A

  By the way, in a hot water supply apparatus, it is possible to change the heating capability according to a condition. 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 changes, so that the heating capacity of the hot water supply device can be changed. On the other hand, if 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 upstream of the compressor and the pressure of the high-pressure refrigerant downstream. The pressure changes. Such a change in the differential pressure of the compressor causes a change in the refrigerant compression load acting on the bearing. If the oil film parameter of the lubricating oil interposed between the outer surface of the drive shaft and the bearing decreases due to changes in the rotational speed of the drive shaft and the refrigerant compression load, the drive shaft and the bearing may come into metal contact and wear out. is there. The oil film parameter is an index that quantifies the lubrication state of the lubricating oil.

  This invention is made | formed in view of such a situation, The objective is to provide the hot-water supply apparatus which can maintain the lubrication state between the drive shaft of a compressor and a bearing more appropriately. .

  In order to solve the above problems, the hot water supply device (10) includes a heat pump cycle (50) and a control unit (59). The heat pump cycle is cooled by a compressor (51) that compresses and discharges a low-pressure refrigerant, a high-pressure side heat exchanger (52) that exchanges heat between the high-pressure refrigerant discharged from the compressor and hot water, and a high-pressure side heat exchanger. An expansion section (53) for decompressing and expanding the refrigerant, and a low-pressure side heat exchanger (54) for generating low-pressure refrigerant by evaporating the refrigerant decompressed and expanded through the expansion section. 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, an electric motor (520) that drives the compression mechanism, and a drive shaft that transmits rotational power from the electric motor to the compression mechanism. (523) and bearings (524, 525) for 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 heating capacity switching mode when switching the heating capacity of the heat pump cycle. The adjustment order of the speed and the refrigerant compression load is changed.

  According to this configuration, when switching the heating capacity of the heat pump cycle, the rotational speed of the drive shaft and the refrigerant compression load are adjusted 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 value. By changing the order, the lubricating state of the lubricating oil can be more appropriately maintained.

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

  ADVANTAGE OF THE INVENTION According to this invention, the lubrication state between the drive shaft of a compressor and a bearing can be maintained more appropriately.

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 the hot water supply apparatus will be described.
As shown in FIG. 1, the hot water supply 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 device 10 is a device that generates hot hot water supply water from, for example, house tap water and discharges it to a hot water supply terminal such as a shower, a currant, or a bathtub.

  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 side heat exchanger 52.

  The high-pressure side heat exchanger 52 integrally includes a refrigerant flow path 52a and a hot water supply water flow path 52b. The high-pressure refrigerant supplied from the compressor 51 flows 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 through the hot water supply water flow path 52b. The high-pressure heat exchanger 52 exchanges heat between the high-pressure refrigerant supplied from the compressor 51 and the hot water supplied from the tank 31, and generates hot hot water by heating the hot water using heat radiation. Then, this hot water is supplied to the upper part of the tank 31.

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

  The expansion valve 53 generates 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 the 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 decompressed and expanded refrigerant through the expansion valve 53. The air blown from the blower 55 to the low pressure side heat exchanger 54 is outside the house. Hereinafter, the air outside the house is abbreviated as “outside air”. 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 heat exchanger 52 to the tank 31. 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 hot water supplied from the high-pressure side 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 hot 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 hot water for hot water stored in the upper part of the tank 31 to the hot water supply terminal. The hot water supply pipe 34 is joined by a water supply pipe 33 branched from the front part of the water supply pipe 32 reaching the tank 31. 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 supplied 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 water stored in the tank 31. The hot water thermistor 37 is provided on the outlet side of the mixing valve 35, and detects the temperature of hot water supplied by the mixing valve 35, that is, the temperature of hot 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 a resident. The operation unit 40 can perform various operations of the hot water supply apparatus 10 such as setting of the temperature of hot water supply water and operation of filling a 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. The hot water storage ECU 38 calculates the amount of hot water stored in the tank 31 by detecting the temperature of the tank 31 and the amount of hot water. Further, the hot water storage ECU 38 determines whether the hot water supply water after boiling at the upper part of the tank 31 and the hot water supply water before boiling at the lower part in the tank 31 are based on the temperature information of the tank 31 obtained from the output signal of the tank thermistor 36. The 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 water obtained based on the output signal of the hot water temperature thermistor 37, operation information of the operation unit 40, and the like. The operations of the tank unit 30 and the heat pump unit 20 are controlled. For example, the hot water storage ECU 38 acquires the set temperature of the hot water supply water based on the operation information of the operation unit 40 and adjusts the 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. To do.

  The hot water storage ECU 38 is communicably connected to the residential power management system 60. The power management system 60 is a system that comprehensively manages the power consumption and 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, at a midnight time zone where the set fee is inexpensive. At this time, the hot water storage ECU 38 instructs the heat pump ECU 59 to perform a boiling operation and transmits the target temperature of hot water supplied to the tank 31 from the heat pump unit 20 to the heat pump ECU 59 to heat the hot water in the tank 31. To do. Note that the power management system 60 instructs the hot water storage ECU 38 to perform a boiling operation when the amount of stored 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 power consumption when there is a possibility that power shortage may occur due to increase in power consumption of a house. In this case, the hot water storage ECU 38 makes a heating capacity change request to the heat pump ECU 59 to reduce the heating capacity of the heat pump cycle 50. The heating capacity change request includes the required heating capacity value. The unit of the heating capacity is “W” or “J / S”. When there is a heating capacity change request from the hot water storage ECU 38, the heat pump ECU 59 compares the required heating capacity value included in the hot pump ECU 38 with the current heating capacity and determines that the current heating capacity is greater than the required value. By reducing the rotation 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 management system 60 informs the hot water storage ECU 38 that the power consumption may be increased if there is room in the power of the house. May direct. In this case, the hot water storage ECU 38 makes a heating capacity change request for increasing the heating capacity of the heat pump cycle 50 to the heat pump ECU 59. When there is a heating capacity change request from the hot water storage ECU 38, the heat pump ECU 59 compares the required heating capacity value included in the hot pump ECU 38 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, an electric motor unit 520, a housing 530, and an oil separator 540. The compression mechanism 510 sucks, compresses and discharges the refrigerant to be compressed. The electric motor unit 520 drives the compression mechanism unit 510. The housing 530 accommodates the compression mechanism unit 510 and the electric motor unit 520. The oil separator 540 is disposed outside the housing 530 and separates 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 the volume of the compression mechanism unit 510.

  The compressor 51 has a drive shaft 523 that transmits rotational power from the electric 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 electric motor unit 520 are arranged side by side 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 unit 510. The refrigerant outlet allows the high-pressure refrigerant discharged from the compression mechanism 510 to flow out to the oil separator 540 side.

  The electric motor unit 520 includes a coil stator 521 that serves as a stator and a rotor 522 that serves as a rotor. A drive shaft 523 is press-fitted into the shaft center hole of the rotor 522 and fixed. Thus, when a rotating magnetic field is generated by supplying power to the coil stator 521, the rotor 522 and the drive shaft 523 rotate together.

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

  The compression mechanism 510 is a scroll-type compression mechanism including a movable scroll 511 having a tooth portion formed in a spiral shape and a fixed scroll 512. The movable scroll 511 is disposed on the lower side in the vertical direction of the housing 530. 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.

  An eccentric portion 523 b that is eccentric with respect to the rotation center of the drive shaft 523 is formed at the lower end portion of the drive shaft 523. The eccentric portion 523b is inserted into a cylindrical boss portion 513 formed on the upper surface of the movable scroll 511 in the vertical direction. In this compressor 51, when the drive shaft 523 rotates, the movable scroll 511 does not rotate around the eccentric portion 523b, but revolves (oscillates) around the rotation center of the drive shaft 523.

  The movable scroll 511 is formed with a spiral tooth portion 511a that protrudes 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 side and meshes with the tooth portion 511 a of the movable scroll 511. The tooth portions 511a and 512a of the scrolls 511 and 512 are engaged with each other and contacted at a plurality of locations, thereby forming a plurality of compression chambers 515 that are formed in a crescent shape when viewed from the direction of the rotation axis. In FIG. 2, for clarity of illustration, only one compression chamber among the plurality of compression chambers 515 is denoted by reference numerals, and the other compression chambers are not denoted by reference numerals. The compression chamber 515 moves while reducing the volume from the outer peripheral side to the center side by the revolving motion of the movable scroll 511. The suction port 531 communicates with a compression chamber 515 positioned on the outermost peripheral side.

  A discharge hole 512b through which the refrigerant compressed in the compression chamber 515 is discharged is formed at the center of the fixed scroll 512. A discharge chamber 512c communicating with the discharge hole 512b is formed below the discharge hole 512b. The discharge chamber 512c is provided with a reed valve (not shown) that forms a check valve that prevents the backflow of refrigerant from the discharge chamber 512c side to the compression chamber 515 side, and a stopper 516 that regulates the maximum opening of the reed valve. Yes.

  A refrigerant passage (not shown) for guiding the refrigerant from the discharge chamber 512c to the refrigerant outlet formed in the housing 530 is formed inside the housing 530. A refrigerant inlet 541 of the oil separator 540 is connected to the refrigerant outlet. The oil separator 540 swirls the refrigerant whose pressure has been increased by the compression mechanism 510 in the 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 a lower portion of the oil separator 540, and the compression mechanism 510 and the drive shaft 523 in the housing 530 and the bearing 524 are disposed via the oil passage 517. 525 is supplied to a sliding portion or 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 capability of the heat pump cycle 50, the pressure of the high-pressure refrigerant discharged from the compressor 51 changes. Accordingly, the differential pressure between the pressure of the low-pressure refrigerant upstream of the compressor 51 and the pressure of the high-pressure refrigerant downstream is changed. Such a change in the differential pressure of the compressor 51 is a factor that changes the refrigerant compression load acting on the bearings 524 and 525. When the oil film parameter of the lubricating oil interposed between the outer surface of the drive shaft 523 and the bearings 524 and 525 decreases due to the change in the rotational speed of the drive shaft 523 and the refrigerant compression load, the drive shaft 523 and the bearings 524 and 525 become metal. They can come into contact and wear.

  Therefore, in this embodiment, when switching the heating capacity of the heat pump cycle 50, the rotation speed of the drive shaft 523 of the compressor 51 and the adjustment sequence of the refrigerant compression load are changed according to the switching mode of the heating capacity. Yes. Below, the content is explained in full detail. Hereinafter, for the sake of 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 relationship of the following formula f1 holds among the oil film parameter Λ 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, the refrigerant compression load F is a small value as compared with the rotational speed V of the drive shaft 523.

  As is apparent from the equation f1, when the viscosity μ of the lubricating oil is assumed to be a constant value, the rotational speed V of the compressor 51 is reduced when both the refrigerant compression load F and the rotational speed V of the compressor 51 are reduced. If it is lowered first, the oil film parameter Λ will be lowered. On the other hand, if the refrigerant compression load F is reduced first, the oil film parameter Λ does not decrease. Therefore, when the heating capacity of the heat pump cycle 50 is reduced, if the rotational speed V of the compressor 51 is reduced after the refrigerant compression load F is reduced, the oil film parameter Λ is set to the drive shaft 523 and the bearings 524, 525. It is possible to suppress the oil film parameter from becoming lower than the lower limit value of the oil film parameter that can maintain the lubrication state of the oil.

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

  Next, a procedure for changing the heating capacity executed by the heat pump ECU 59 based on the above principle will be described.

  The heat pump ECU 59 executes the processing shown in FIG. 3 when the heating capacity change request is received from the hot water storage ECU 38. As shown in FIG. 3, the heat pump ECU 59 first determines whether or not the current heating capacity Q1 is larger than the required heating capacity value Q2 as a process of step S10. When the heat pump ECU 59 makes an affirmative determination in the process of step S10, that is, when the current heating capacity Q1 is larger than the required value Q2 of the heating capacity, first, as the process of step S11, the refrigerant compression load F is first set as the current load. 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 below the current rotational speed as the process of step S12.

  When the heat pump ECU 59 makes a negative determination in the process of step S10, that is, when the current heating capacity Q1 is equal to or less than the required heating capacity value Q2, first, as the process of step S13, the rotational speed V of the compressor 51 is determined. Is raised above the current rotation speed. Thereafter, the heat pump ECU 59 increases the refrigerant compression load F from the current load as the process of step S14. Specifically, the heat pump ECU 59 increases 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 device 10 of the present embodiment described above, the operations and effects shown in the following (1) and (2) can be obtained.

  (1) When the heat pump ECU 59 switches 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 heating mode switching mode. Specifically, the heat pump ECU 59 reduces the rotational speed V of the compressor 51 after reducing the refrigerant compression load F when the heating capacity of the heat pump cycle 50 is reduced below the current heating capacity Q1. Further, the heat pump ECU 59 increases the refrigerant compression load F after increasing the rotational speed V of the compressor 51 when the heating capacity of the heat pump cycle 50 is increased above the current heating capacity Q1. Thereby, since it can suppress that the oil film parameter of the lubricating oil interposed between the drive shaft 523 and the bearings 524, 525 becomes smaller than the lower limit value, 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 reduces the refrigerant compression load F of the compressor 51 from 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 increases the refrigerant compression load F of the compressor 51 from the current load by making the opening degree of the expansion valve 53 smaller than the current opening degree. Thereby, the refrigerant | coolant compression load F of the compressor 51 can be adjusted easily.

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

  The heat pump ECU 59 of the present embodiment executes the process shown in FIG. 4 instead of the process shown in FIG. 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-described equation 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 temperature detected by 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 in 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 and 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 and arithmetic expressions.

  The heat pump ECU 59 has a map, an arithmetic expression, and the like showing 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. Obtain the oil film parameter Λ of the lubricating oil.

  As shown in FIG. 4, the heat pump ECU 59 calculates a difference value ΔΛ (= Λ−Λmin) between the calculated value of the oil film parameter Λ and the lower limit value Λmin of the oil film parameter as the process of step S21 following the process of step S20. To do. Next, the heat pump ECU 59 sets the adjustment amount of the refrigerant compression load F and the adjustment amount of the rotational 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 a predetermined value, the heat pump ECU 59 determines that there is a margin in the lubrication 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 the normal value. The predetermined value is set in advance by experiments or the like so that it can be determined whether 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 lubrication 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. Is set to a value smaller than the normal value.

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

  According to the hot water supply device 10 of the present embodiment described above, the operation and effect shown in the following (3) can be obtained.

  (3) The heat pump ECU 59 adjusts the refrigerant compression load F and the rotation speed V of the compressor 51 based on the calculated value of the oil film parameter Λ. Thereby, since the refrigerant | coolant compression load F and the rotational speed V of the compressor 51 can be changed more appropriately according to the actual oil film parameter (LAMBDA), the lubrication state of lubricating oil can be maintained further appropriately.

<Other embodiments>
In addition, each embodiment can also be implemented with the following forms.
-The temperature acquisition part 590 of 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 2nd pressure acquisition part 592 of 2nd Embodiment may acquire the pressure of the low pressure refrigerant | coolant of the compressor 51 based on the output signal of the sensor which detects the pressure of the low pressure refrigerant | coolant of the compressor 51 directly. .

  -The method of changing the refrigerant | coolant compression load F of the compressor 51 can be changed suitably. 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 above the current rotational speed. Further, the heat pump ECU 59 increases the refrigerant compression load F of the compressor 51 by reducing the rotational speed of the fan of the blower 55 from the current rotational speed.

  -The structure of each embodiment is employable also in the heat pump cycle 50 in which the ejector is used instead of the expansion valve 53. The ejector includes 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 from the low-pressure side heat exchanger 54, and a nozzle And a diffuser for increasing the pressure by mixing the refrigerant ejected from the refrigerant and the refrigerant sucked by the suction portion. In such a heat pump cycle 50, the refrigerant compression load F of the compressor 51 can be changed by adjusting the opening of the ejector.

  The means and / or function 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 the software, 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 hardware electronic circuits, they can be provided by digital circuits including a large number of logic circuits, or analog circuits.

  -This invention is not limited to said specific example. That is, the above-described specific examples that are appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above, their arrangement, conditions, and the like are not limited to those illustrated, and can be changed as appropriate. Moreover, each element with which embodiment mentioned above is provided can be combined as long as it is technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention.

10: Hot water supply apparatus 50: Heat pump cycle 51: Compressor 52: High-pressure side heat exchanger 53: Expansion valve (expansion part)
54: Low pressure side heat exchanger 55: Blower 59: Heat pump ECU (control unit)
510: Compression mechanism unit 520: Electric 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) that compresses and discharges the low-pressure refrigerant, a high-pressure side heat exchanger (52) that exchanges heat between the high-pressure refrigerant discharged from the compressor and hot water, and the refrigerant cooled by the high-pressure side heat exchanger A heat pump cycle (50) having an expansion part (53) that decompresses and expands, a low-pressure side heat exchanger (54) that generates the low-pressure refrigerant by evaporating the refrigerant decompressed and expanded through the expansion part,
A controller (59) for controlling the heat pump cycle,
The compressor rotates from the motor part to the compression mechanism part, a compression mechanism part (510) that compresses the low-pressure refrigerant to generate the high-pressure refrigerant, an electric motor part (520) that drives the compression mechanism part, and 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 the differential pressure between the high-pressure refrigerant and the low-pressure refrigerant is a refrigerant compression load,
The controller is a hot water supply apparatus that changes the rotation 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. The hot water supply apparatus according to claim 1, wherein when the heating capacity of the heat pump cycle is lower than a current heating capacity, the control unit reduces the rotational speed of the drive shaft after reducing the refrigerant compression load. . The hot water supply apparatus according to claim 1, wherein, when the heating capacity of the heat pump cycle is increased above the current heating capacity, the control unit increases the refrigerant compression load after increasing the rotational speed of the drive shaft. . The controller is
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 the lubricating oil interposed between the drive shaft and the bearing,
Calculate the refrigerant compression load based on the pressure of the high-pressure refrigerant and the pressure of the low-pressure refrigerant,
Calculate the viscosity of the lubricating oil based on the temperature of the lubricating oil,
Based on the rotational speed of the drive shaft, the refrigerant compression load, and the viscosity of the lubricating oil, the oil film parameter of the lubricating oil is calculated,
The hot water supply device according to any one of claims 1 to 3, wherein a rotational speed of the drive shaft and the refrigerant compression load are adjusted based on the oil film parameter. The hot water supply apparatus 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. A blower (55) for blowing air to the low-pressure 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 rotation speed of a fan of the blower.

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