JP2018136099A - Heat pump type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid operation in a state where the temperature difference ΔT between a discharge refrigerant temperature and a compressor temperature is small, to secure reliability of a compressor, in the initial stage of start of boiling-up operation with activation control of stepwisely increasing a rotational frequency of the compressor from a low rotational frequency.SOLUTION: A heat pump type water heater is configured to, when activation control of stepwisely increasing a rotational frequency of a compressor from a predetermined rotational frequency according to a detection value of an ambient temperature sensor, is performed in hot water supply operation start, perform, before the activation control, pre-activation control of driving the compressor at a rotational frequency higher than the predetermined rotational frequency, according to an ambient temperature detected by the ambient temperature sensor.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heat pump hot water supply apparatus, and more particularly to a technique for controlling the start of a compressor at the start of a hot water supply operation.

  The heat pump type hot water supply device includes, as a basic configuration, a refrigerant circuit in which a compressor, a use side heat exchange unit, an expansion valve, and a heat source side heat exchanger are sequentially connected via a refrigerant pipe, and a hot water storage tank. The usage-side heat exchange unit has, for example, a configuration in which a refrigerant pipe is wound around the outer periphery of the hot water storage tank, switches the refrigerant circuit so that the usage-side heat exchanger acts as a condenser, and heats the water and the refrigerant in the hot water storage tank. The water in the hot water storage tank is heated by replacement.

  In such a heat pump type hot water supply apparatus, a boiling operation is performed such that the water temperature in the hot water storage tank becomes a hot water temperature (target water temperature) that is finally desired to reach. In the boiling operation, the high-temperature and high-pressure refrigerant discharged from the compressor flows into the use-side heat exchanger, exchanges heat with the water in the hot water storage tank, and condenses. The condensed refrigerant is depressurized by the expansion valve and evaporated by the heat source side heat exchanger to return to the compressor as a low-pressure gas refrigerant.

  By the way, when performing the boiling operation as described above, if the compressor is driven at the maximum allowable rotation speed from the start of the operation until just before the water temperature in the hot water storage tank reaches the target water temperature, a condenser is used during the boiling operation. As a result, the state in which the condensing pressure in the use-side heat exchange unit that functions as a high pressure continues to be high, and the operating load of the compressor increases.

  If the operating load of the compressor increases, the amount of power consumed by the compressor increases accordingly, and the operating efficiency of the refrigerant circuit may decrease, leading to a decrease in efficiency of the boiling operation.

  Therefore, in the invention described in Patent Document 1, at the time of starting up the boiling operation, start-up control is performed in which the rotational speed of the compressor is increased stepwise from a low rotational speed (for example, 20 rps). As a result, the condensing pressure of the use side heat exchanger is not maintained in a high state, thereby preventing the power consumption of the compressor from increasing.

JP2013-155991A

  However, when the compressor is started in an environment where the outside air temperature is low, the temperature difference between the high-pressure side refrigerant temperature discharged from the compressor and the temperature of the compressor itself (for example, the temperature of the sealed container) (hereinafter referred to as temperature difference ΔT). If it is small, there is a risk that the reliability of the compressor may be impaired, such as driving in a state where the refrigerant is dissolved in the refrigeration oil, that is, so-called stagnation driving, and refrigeration oil being discharged in a large amount into the refrigerant circuit. is there.

  As in the invention described in Patent Document 1 described above, according to the method of gradually increasing the rotational speed of the compressor at the start-up of the boiling operation as the start-up control, it takes time until the rotational speed of the compressor increases. As a result, it takes time to increase the temperature of the refrigerant on the high pressure side discharged from the compressor. Therefore, it takes time until the temperature difference ΔT becomes large, and there is a possibility that the problem due to the stagnation drive may occur. Get higher.

  Accordingly, an object of the present invention is to avoid the operation in the state where the temperature difference ΔT is small at the start of the boiling operation by the start control in which the rotation speed of the compressor is increased stepwise from a low rotation speed, and the reliability of the compressor is reduced. It is to ensure sex.

In order to solve the above problems, the present invention provides a refrigerant pipe including a compressor, a flow path switching unit, a hot water supply terminal, a use side heat exchange unit that performs heat exchange between water and refrigerant in the hot water supply terminal, and a heat source side heat exchanger. A refrigerant circuit that is sequentially connected via the external air temperature sensor, an outside air temperature sensor that detects the outside air temperature, and a control means, wherein the control means detects the rotational speed of the compressor at the start of the hot water supply operation. In a heat pump type hot water supply apparatus that performs start-up control to increase stepwise from a predetermined number of revolutions determined in advance according to a value,
The control means performs pre-startup control for driving the compressor for a predetermined time at a rotation speed higher than the predetermined rotation speed in accordance with the outside air temperature detected by the outside air temperature sensor before performing the start-up control. It is characterized by what it does.

  According to a preferred aspect of the present invention, the control means sets the compressor rotational speed of the pre-startup control to a fixed rotational speed.

  The control means performs the pre-startup control when the outside air temperature is equal to or lower than a predetermined temperature. Further, during the pre-startup control, the compressor rotational speed is increased as the outside air temperature is lowered, and the driving time is lengthened as the outside air temperature is lowered.

  According to the present invention, as an energy-saving operation, before performing start-up control in which the compressor is stepped up from a predetermined number of revolutions according to the outside air temperature so that the water temperature in the hot water storage tank reaches the target water temperature at the start of the hot water supply operation. By performing the pre-startup control, the operation by the so-called sleep drive described above when the outside air temperature is low can be avoided, and the reliability of the compressor can be ensured.

The schematic diagram which shows the structure of the heat pump type hot-water supply apparatus by this invention. 3 is a timing chart showing the operation of the present invention. The schematic diagram which shows the table for a reference at the time of the control before starting with which a control means is provided.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. As an embodiment, a heat pump type hot water supply apparatus that has a hot water storage tank that is a hot water supply terminal and heats water stored in the hot water storage tank by heat exchange with the refrigerant will be described as an example. In addition, this invention is not limited to the following embodiment, A various deformation | transformation is possible in the range which does not deviate from the main point of this invention.

  FIG. 1 shows a configuration of a heat pump hot water supply apparatus according to the present invention. The heat pump type hot water supply apparatus 100 includes a variable capacity compressor 1, a four-way valve 2 as a flow path switching unit, and a heat on the use side configured by winding a part of a refrigerant pipe 11 (described later) around the outer periphery of a hot water storage tank 70. It has a refrigerant circuit 10 in which the exchange unit 3, the expansion valve 4, the heat source side heat exchanger 5, and the accumulator 6 are connected in order by the refrigerant pipe 11, and the refrigerant circulation direction can be switched by switching the four-way valve 2. It is like that.

  In this refrigerant circuit 10, a refrigerant pipe 11 near the refrigerant outlet of the compressor 1 is provided with a discharge temperature sensor 51 for detecting the temperature of the refrigerant discharged from the compressor 1. Further, the refrigerant pipe 11 between the heat exchange unit 3 and the expansion valve 4 has a temperature of the refrigerant flowing out from the heat exchange unit 3 when the heat exchange unit 3 functions as a condenser, or heat exchange. A refrigerant temperature sensor 53 for detecting the temperature of the refrigerant flowing into the heat exchange unit 3 when the unit 3 functions as an evaporator is provided.

  The refrigerant pipe 11 between the expansion valve 4 and the heat source side heat exchanger 5 has a temperature of the refrigerant flowing into the heat source side heat exchanger 5 when the heat source side heat exchanger 5 functions as an evaporator. Or a heat exchange temperature sensor 54, which is a heat exchange temperature detecting means for detecting the temperature of the refrigerant flowing out of the heat source side heat exchanger 5 when the heat source side heat exchanger 5 functions as a condenser. Is provided.

  Further, the refrigerant pipe 11 on the discharge side of the compressor 1 (between the four-way valve 2 and the heat exchanging unit 3) is heated during the boiling operation, that is, when the heat exchanging unit 3 functions as a condenser. A pressure sensor 50 that detects the condensation pressure of the refrigerant in the exchange unit 3 is provided. In the vicinity of the heat source side heat exchanger 5, an outside air temperature sensor 52, which is an outside air temperature detecting means, is provided.

  In the vicinity of the heat source side heat exchanger 5, a fan 7 that takes outside air into a housing (not shown) of the heat pump hot water supply apparatus 100 and distributes the outside air to the heat source side heat exchanger 5 is disposed. The fan 7 is attached to an output shaft (rotary shaft) of a motor (not shown) that can vary the rotational speed. Further, the expansion valve 4 uses a stepping motor to enable pulse control of the opening degree of the valve.

  The heat exchange unit 3 is included in a part of the refrigerant pipe 11. In the present embodiment, the heat exchanging unit 3 is configured by spirally winding a part of the refrigerant pipe 11 around the lower side of the outer peripheral surface of the hot water storage tank 70, and performs heat exchange with water in the hot water storage tank 70.

  The heat exchange unit 3 may be disposed in the hot water storage tank 70. Further, although not shown, the heat exchanging unit 3 causes the water in the hot water storage tank 70 to flow into the heat exchanging unit 3 so that the refrigerant and the refrigerant flow like a double pipe heat exchanger having a refrigerant side channel and a water side channel. Heat exchange may be performed.

  A hot water supply port 73 for supplying hot water stored in the hot water storage tank 70 to a bathtub, a washbasin faucet or the like is provided at the upper part of the hot water storage tank 70. In addition, a water inlet 72 for supplying water to the hot water storage tank 70 is provided below the hot water storage tank 70, and a water pipe (not shown) is connected to the water inlet 72.

  Further, a water temperature sensor 58 for detecting the temperature of the hot water staying in the hot water storage tank 70 is provided at a substantially central portion in the vertical direction inside the hot water storage tank 70.

  In addition to the configuration described above, the heat pump hot water supply apparatus 100 has a control means 60. The control means 60 takes in the temperature detected by each temperature sensor 51, 52, 53, 54, 58 and the refrigerant pressure during the boiling operation detected by the pressure sensor 50, or the operation from the user by a remote controller (not shown). In response to these requests, various controls relating to the operation of the heat pump hot water supply apparatus 100 such as drive control of the compressor 1 and the fan 7, switching control of the four-way valve 2, opening control of the expansion valve 4 and the like are performed.

  In addition, although illustration is abbreviate | omitted, the control means 60 has a memory | storage part which memorize | stores the timer part which measures time, the value detected with various sensors, the control program of the heat pump type hot-water supply apparatus 100, etc.

  Next, the flow of the refrigerant and the operation of each part in the refrigerant circuit 10 provided in the heat pump type hot water supply apparatus 100 of the present embodiment will be described.

  The heat pump type hot water supply apparatus 100 according to the present embodiment uses the refrigerant circuit 10 as a heating cycle to boil the water stored in the hot water storage tank 70, and the refrigerant circuit 10 to perform a cooling cycle when performing the boiling operation. The reverse cycle defrost operation which defrosts the heat source side heat exchanger 5 can be performed.

  In the boiling operation, the refrigerant flows in the direction of the solid line arrow 80 in FIG. 1, whereas in the reverse cycle defrosting operation, the four-way valve 2 is switched and the refrigerant flows in the direction of the broken line arrow 81 in FIG. In the reverse cycle defrosting operation, since there is no particular feature, a detailed description thereof will be omitted, and the operation of the heat pump hot water supply apparatus 100 during the boiling operation will be described below.

<Boiling operation>
When the user operates a remote controller (not shown) to instruct the start of the boiling operation, the control means 60 switches the four-way valve 2 so that the refrigerant circuit 10 enters the heating cycle. Specifically, the control means 60 is connected so that the discharge side of the compressor 1 and the heat exchange unit 3 are connected, and so that the suction side of the compressor 1 and the heat source side heat exchanger 5 are connected. Switch the four-way valve 2. Thereby, the heat exchange part 3 functions as a condenser, and the heat source side heat exchanger 5 functions as an evaporator.

  Next, the control means 60 starts the compressor 1 and the fan 7, and starts the boiling operation of the heat pump type hot water supply apparatus 100. The control means 60 determines the temperature difference stored in the storage unit and the rotation speed of the compressor 1 according to the temperature difference between the current water temperature in the hot water storage tank 70 detected by the water temperature sensor 58 and the boiling target temperature. The rotation speed of the compressor 1 is determined with reference to the related table (not shown), and the compressor is driven at this rotation speed.

  When the compressor 1 is driven, the high-temperature and high-pressure refrigerant discharged from the compressor 1 passes through the four-way valve 2 and is condensed by exchanging heat with water in the heat exchange unit 3 as indicated by a solid arrow 80 in FIG. Further, the pressure is reduced by the expansion valve 4, the heat is exchanged with the outside air by the heat source side heat exchanger 5, the gas is evaporated by the accumulator 6, and then sucked into the compressor 1 and compressed again by the compressor 1. Repeat the process.

  In this way, when the water in the hot water storage tank 70 is heated by the high-temperature and high-pressure refrigerant flowing through the heat exchanging unit 3 and the water temperature in the hot water storage tank 70 reaches the target temperature, the control means 60 is connected to the compressor 1 and the fan. The operation of 7 is stopped.

  The control means 60 constantly monitors the water temperature in the hot water storage tank 70 detected by the water temperature sensor 58, and when the water temperature drops from a boiling target temperature to a predetermined temperature (for example, 5 ° C.), boiling is performed. Restart the driving operation.

  By the way, as described above, if the compressor 1 is continuously driven at the maximum rotational speed from the start of the boiling operation, the heat exchange unit 3 becomes high temperature and the state is continued. On the other hand, immediately after the start of the boiling operation, that is, when the water temperature in the hot water storage tank is low and the temperature difference from the target water temperature is large, the hot water storage tank 70 is caused by the large heat capacity of the water in the hot water storage tank 70. The water temperature in 70 does not rise as much as the temperature of the heat exchange unit 3.

  As a result, the state in which the condensing pressure in the heat exchanging unit 3 becomes high continues, and as a result, the operating load of the compressor 1 increases and the power consumption in the compressor 1 increases. There is a possibility that the operation efficiency is lowered and the efficiency of the boiling operation is lowered.

  Therefore, in the heat pump type hot water supply apparatus 100, at the start of the boiling operation, as shown in the timing chart of FIG. Starting at a predetermined rotational speed corresponding to the predetermined rotational speed in the embodiment), and then the rotational speed of the compressor 1 is increased stepwise in accordance with the rise in the water temperature in the hot water storage tank 70 detected by the water temperature sensor 58. (For details on the startup control of the compressor 1, refer to, for example, Japanese Patent Application Laid-Open No. 2013-155991).

  According to such start-up control of the compressor 1, it is possible to prevent the operation of the heat exchanging unit 3 from being continued in a high temperature state, that is, from continuing the operation in a state where the condensation pressure is high. 1 can be prevented from increasing.

  However, when the compressor 1 is started in an environment where the outside air temperature is low, ΔT which is a temperature difference between the high-pressure side refrigerant temperature discharged from the compressor 1 and the temperature of the compressor 1 itself (for example, the temperature of the sealed container) is When it is small, the compressor 1 is operated in a state where a large amount of refrigerant is dissolved in the refrigeration oil, that is, a so-called stagnation drive, and a large amount of refrigeration oil is discharged into the refrigerant circuit. There is a risk of damage.

  In particular, according to the above-described start-up control, according to the method of gradually increasing the rotational speed of the compressor from the low rotational speed at the start of the boiling operation, it takes time until the rotational speed of the compressor increases. Since it takes time for the refrigerant temperature on the high-pressure side to be discharged to increase and the temperature difference ΔT to increase, there is a high possibility that problems due to the stagnation drive (flow of refrigeration oil to the refrigerant circuit) will occur. .

  Therefore, in the present invention, as a pre-startup control before performing the start-up control according to the outside air temperature detected by the outside-air temperature sensor 52, the compressor 1 is rotated at a speed higher than the starting speed at the start-up control. By driving for a predetermined time, the operation in a state where the temperature difference ΔT is small is avoided and the reliability of the compressor 1 is ensured.

  With reference to the timing chart of FIG. 2, the pre-startup control is control performed before start-up control in which the rotational speed of the compressor 1 is increased stepwise from a low rotational speed (starting rotational speed) during the boiling operation. .

  As a specific example, FIG. 3 shows the number of rotations of the compressor 1 at the time of start-up control set according to the outside air temperature To, its hold time, and the number of start rotations at the time of start-up control. It should be noted that the compressor rotation speed, hold time, and starting rotation speed shown in FIG. 3 are obtained by conducting a test or the like in advance, and it has been confirmed that no sleep driving is performed.

According to this, when the control means 60 starts the boiling operation in response to an instruction from the user or a decrease in the hot water temperature in the hot water storage tank 70,
When the outside air temperature To is 10 ° C. or higher (10 ° C. ≦ To), the start-up control is executed with the starting rotational speed set at 25 rps without performing the pre-start-up control.

  When the outside air temperature To is 0 ° C. or more and less than 10 ° C. (0 ° C. ≦ To <10 ° C.), the compressor 1 is driven at a rotation speed of 30 rps for 10 minutes as a pre-startup control, and then started at a starting rotation speed of 25 rps. Execute control.

  When the outside air temperature To is −10 ° C. or higher and lower than 0 ° C. (−10 ° C. ≦ To <0 ° C.), the compressor 1 is driven at a rotational speed of 50 rps for 15 minutes as a pre-startup control, and then the starting rotational speed is set to 30 rps. Start control is executed as follows.

  When the outside air temperature To is −20 ° C. or higher and lower than −10 ° C. (−20 ° C. ≦ To <−10 ° C.), the compressor 1 is driven at a rotational speed of 70 rpm for 15 minutes as a pre-startup control, and then the starting rotational speed Is controlled at 40 rps.

  When the outside air temperature To is less than −20 ° C. (To <−20 ° C.), the compressor 1 is driven at a rotation speed of 90 rps for 20 minutes as a pre-startup control, and then the start-up control is executed at a starting rotation speed of 50 rps. .

  Thus, by performing the pre-startup control when the outside air temperature is lower than the predetermined temperature (10 ° C. in the above example), the operation due to the sleep drive is avoided, and the reliability of the compressor can be ensured.

  As described above, in the present invention, under conditions where the outside air temperature is low and the above temperature difference ΔT cannot be obtained, before starting the compressor, before starting control, the control is performed at a higher rotational speed than the starting rotational speed at the start control. When the temperature difference ΔT is ensured (5 ° C. <ΔT) after driving for a predetermined time, start-up control with excellent energy saving is performed. Thereby, the driving | operation by what is called a sleep drive is avoided and the reliability of a compressor can be ensured.

DESCRIPTION OF SYMBOLS 100 Heat pump type hot water supply apparatus 1 Compressor 2 Four-way valve 3 Heat exchange part (use side heat exchanger)
DESCRIPTION OF SYMBOLS 4 Expansion valve 5 Heat source side heat exchanger 6 Cumulator 7 Fan 10 Refrigerant circuit 11 Refrigerant piping 51 Discharge temperature sensor 52 Outside temperature sensor 53 Refrigerant temperature sensor 58 Water temperature sensor 60 Control means 70 Hot water storage tank

Claims (4)

A refrigerant circuit formed by sequentially connecting a compressor, a flow path switching unit, a hot water supply terminal, a use side heat exchange unit that performs heat exchange between the water in the hot water supply terminal and the refrigerant, and a heat source side heat exchanger via a refrigerant pipe; And an outside air temperature sensor for detecting the outside air temperature, and a control means, wherein the control means determines the number of revolutions of the compressor at a predetermined number of revolutions according to a detection value of the outside air temperature sensor at the start of the hot water supply operation. In the heat pump type hot water supply device that performs start-up control to raise in stages from
The control means performs pre-startup control for driving the compressor for a predetermined time at a rotation speed higher than the predetermined rotation speed in accordance with the outside air temperature detected by the outside air temperature sensor before performing the start-up control. A heat pump type hot water supply device characterized in that it is performed.   The heat pump type hot water supply apparatus according to claim 1, wherein the control means sets the compressor rotational speed of the pre-startup control to a fixed rotational speed.   The heat pump type hot water supply apparatus according to claim 1 or 2, wherein the control means performs the pre-startup control when the outside air temperature is equal to or lower than a predetermined temperature.   The rotation speed of the compressor in the pre-startup control is increased as the outside air temperature is lowered, and the driving time is increased as the outside air temperature is lowered. The heat pump type hot water supply apparatus according to item.

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