JP2011080716A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump water heater capable of performing defrosting operation according to outside temperature, temperature of an air heat exchanger, an amount of frost formation of the air heat exchanger, and an amount of stored liquid in a tank. <P>SOLUTION: The heat pump water heater 100 includes a heat pump unit 30, a hot water storage unit 40, and an operation control device 50 and can perform defrosting operation for defrosting the air heat exchanger 4 of the heat pump unit 30. The operation control device 50 determines whether the defrosting operation is necessary or not, and further determines timing of starting the defrosting operation, based on a criterion for determining to start defrosting in which a determination result is set in every section according to the outside temperature and the temperature of the air heat exchanger 4 and in which the timing of starting the defrosting operation is set according to a hot water storage amount of the hot water storage tank 9. The operation control device 50 determines the end of the defrosting operation based on a criterion for determining to end defrosting in which temperature for ending defrosting is set in every section according to the outside temperature. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat pump water heater, and more particularly to a heat pump water heater capable of a defrosting operation for defrosting an air heat exchanger (evaporator).

  Conventionally, a heat pump water heater operates a heat pump when the electricity rate is low, such as at night, to boil hot water and store hot water in a large-capacity hot water storage tank, and the user is heated up at night to hot water storage tank A hot water storage type that uses hot hot water stored in the daytime is common.

Since such a hot water storage type heat pump water heater is operated for a long time at night when the outside air temperature is low in winter, for example, the air heat exchanger may be frosted.
When the air heat exchanger is frosted, the efficiency of heat exchange between the outside air and the refrigerant is lowered, and the heating performance when boiling hot water is lowered. Therefore, a defrosting operation is necessary at low temperatures in winter.

As a conventional example of a defrosting operation of a heat pump water heater, for example, a technique disclosed in Patent Document 1 is known.
The technique disclosed in Patent Document 1 is a technique for changing the start condition of the defrosting operation according to the heating capacity of the heat pump, and specifically, when the heating capacity is small (small capacity) such as in the case of a single hot water supply operation. Increases the defrosting start temperature, and lowers the defrosting start temperature when the heating capacity is large (high capacity) such as when performing hot water supply operation and heating operation simultaneously.

  With this configuration, when the heating capacity of the heat pump is switched from the small capacity to the large capacity, the boiling operation can be continued without shifting to the defrosting operation, and the defrosting operation can be performed at an appropriate timing.

JP 2006-220357 A

  However, for example, when the conventional heat pump water heater shown in Patent Document 1 is operated in the same operation mode without switching the heating capacity, the outside air temperature and the frost formation amount of the air heat exchanger (evaporator) Regardless of whether the start or end of the defrosting operation is determined based on the temperature of the air heat exchanger (exchanger temperature).

For this reason, for example, even if only a short time has elapsed since the start of the operation of the heat pump water heater and the amount of frost formation is small and the heating capacity has not decreased so much, it is excluded when the outside air temperature is low. The frost start temperature may be reached, and the hot water storage operation may be interrupted to start the defrost operation. For this reason, there is a problem that the time required for the hot water storage operation becomes longer and the power consumption increases.
In addition, when the outside air temperature is particularly low, when the hot water storage operation is resumed after the defrosting operation is completed, the temperature of the air heat exchanger may rapidly decrease, and the water melted by the defrosting operation may be frozen again. .
Furthermore, since the defrosting start temperature is set based on the heating capacity only, regardless of the amount of hot water stored in the hot water storage tank, the defrosting operation is started even immediately before the hot water storage operation is finished in a state where the hot water storage tank is almost full. There is.

  Thus, for example, the heat pump water heater shown in Patent Document 1 determines the defrosting start and the defrosting end only by the temperature of the air heat exchanger, and the outside air temperature, the temperature of the air heat exchanger, Appropriate defrosting operation corresponding to the frost formation amount of the air heat exchanger and the hot water storage amount of the hot water storage tank is a necessary issue.

Such a problem is not limited to a hot water storage type heat pump water heater in which boiling water is stored in a hot water storage tank, but a heat pump hot water supply of a type in which a high temperature liquid as a heat medium is stored in the tank. It is a problem common to all machines.
Moreover, the heat source is not limited to an electric water heater of a type that exists independently as a heat pump unit, and is common to a heat pump water heater of a type in which a tank and a heat source are provided integrally and the heat source is provided as a heat pump unit. It is a problem.

  Then, this invention makes it a subject to provide the heat pump water heater which can perform the defrost operation according to the external temperature, the temperature of an air heat exchanger, the amount of frost formation of an air heat exchanger, and the amount of liquid storage of a tank. .

  In order to solve the above problems, the present invention includes a heat pump unit serving as a heat source for boiling a liquid to a predetermined boiling temperature, and a liquid storage unit for storing the liquid at the boiling temperature in a tank, A heat pump water heater having defrosting start determining means for determining the start of a defrosting operation for defrosting the air heat exchanger provided in the heat pump unit and defrosting end determining means for determining the end of the defrosting operation is provided. And the said defrost start determination means is based on the defrost start determination criterion by which a determination result is set for every division according to the outside air temperature, the temperature of the said air heat exchanger, and the amount of frost formation of the said air heat exchanger. The start of the defrosting operation is determined, and the defrosting end determining means determines the end of the defrosting operation based on a defrosting end determination criterion in which a defrosting end temperature is set for each section according to the outside air temperature. It is characterized by doing.

  ADVANTAGE OF THE INVENTION According to this invention, the heat pump water heater which can perform the defrost operation according to external temperature, the temperature of an air heat exchanger, the amount of frost formation of an air heat exchanger, and the amount of liquid storage of a tank can be provided.

It is a figure which shows one structural example of a heat pump water heater. It is a figure which shows an example of a defrost start determination criterion. It is a flowchart which shows the procedure of a defrost start determination. It is a figure which shows an example of the defrost completion | finish determination criteria. It is a flowchart which shows the procedure of completion | finish determination of a defrost. It is a flowchart which shows the procedure of a defrost operation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, a heat pump water heater 100 according to the present embodiment includes a heat pump unit 30 as a heat pump unit serving as a heat source for boiling hot water (liquid), and a hot water storage unit for storing hot water that has been boiled up. 40 (liquid storage unit) and an operation control device 50 are provided.
In the following description, “high temperature” indicates a boiling temperature, and “low temperature” indicates a temperature lower than the boiling temperature. And let boiling temperature be the temperature preset as the specification of the heat pump water heater 100, for example.

The heat pump unit 30 includes a compressor 1, a water-refrigerant heat exchanger 2, an expansion valve 3, and an air heat exchanger 4 (also referred to as an evaporator) provided with an air heat exchanger thermistor 4a, which are connected by a refrigerant pipe 30a. The sealed refrigerant is configured to circulate.
Further, a water circulation pump 14 for sending hot water to the water refrigerant heat exchanger 2, a blower fan 5a for taking in outside air for cooling the refrigerant flowing through the air heat exchanger 4, and a fan motor 5 for driving the blower fan 5a are provided. ing.

  A heat pump is connected to the compressor 1, the refrigerant side heat transfer pipe 2a, the expansion valve 3 and the air heat exchanger 4 which are connected to the refrigerant pipe 30a and circulate through the refrigerant, and are arranged in the water refrigerant heat exchanger 2. A refrigerant circuit 31 is formed.

The capacity of the compressor 1 can be controlled. For example, when a large amount of hot water is boiled, the compressor 1 is operated with a large capacity.
The compressor 1 is controlled between a low speed (for example, 700 rpm) and a high speed (for example, 7000 rpm) by PWM (Pulse Width Modulation) control, voltage control (for example, PAM (Pulse Amplitude Modulation) control), and a combination thereof. The rotation speed can be controlled with the.

  The water-refrigerant heat exchanger 2 is provided with a refrigerant-side heat transfer tube 2a and a water supply-side heat transfer tube 2b, and exchanges heat between the refrigerant flowing through the refrigerant-side heat transfer tube 2a and hot water flowing through the water-supply-side heat transfer tube 2b. Is configured to be performed.

As the expansion valve 3, an electric expansion valve having a high response speed of opening adjustment is used, and the refrigerant introduced from the water-refrigerant heat exchanger 2 is decompressed to be easily evaporated and sent to the air heat exchanger 4. .
Further, the expansion valve 3 can adjust the circulation amount of the refrigerant in the heat pump refrigerant circuit 31 of the heat pump unit 30 by adjusting the valve opening degree.
For example, when the heat pump water heater 100 performs a defrosting operation, the expansion valve 3 can send a large amount of medium temperature refrigerant to the air heat exchanger 4 by increasing the valve opening, and the air heat exchanger 4 is defrosted. it can.

  The air heat exchanger 4 takes in outside air by a blower fan 5a that is rotationally driven by a fan motor 5, and exchanges heat between the outside air and a refrigerant to absorb the heat of the outside air.

The hot water storage unit 40 includes a water supply fitting 6, a pressure reducing valve 7, a water supply amount sensor 8, a hot water storage tank 9 (tank), a hot water supply mixing valve 10, a hot water mixing valve 11, and a hot water supply fitting 12 in this order via a water pipe 40b. A hot water supply circuit 42 is formed by being connected.
Further, the hot water storage tank 9, the water circulation pump 14 provided in the heat pump unit 30, the water supply side heat transfer pipe 2b piped to the water refrigerant heat exchanger 2 of the heat pump unit 30, and the hot water supply mixing valve 10 are arranged in this order via the water pipe 40a. Connected to form a hot water storage circuit 41.

The hot water storage tank 9 is a tank for storing hot hot water (liquid) heated by the hot water storage operation. The hot water storage tank 9 has a water pipe 40b, a hot water supply mixing valve 10, a hot water mixing valve 11, and a hot metal fitting 12 at the upper part. A hot water tap 13 such as a kitchen faucet is connected.
When the hot water tap 13 is opened by the user, the hot water stored in the upper portion of the hot water storage tank 9 is taken out from the upper portion of the hot water storage tank 9 and supplied to the user via the hot water tap 13.

Further, a water supply source such as a water supply (not shown) is connected to the lower part of the hot water storage tank 9 through a water pipe 40 b, a water supply fitting 6, a pressure reducing valve 7, and a water supply water amount sensor 8. The water supply fitting 6 is connected to a water supply source, and low temperature water is supplied to the lower part of the hot water storage tank 9 from a water supply source (not shown).
Further, the hot water storage tank 9 is provided with a plurality of tank thermistors 9a for measuring the temperature of the hot water stored.

The hot water storage operation refers to an operation in which low temperature hot water is boiled by the heat pump unit 30 and stored in the hot water storage tank 9 as high temperature hot water.
An operation for supplying hot water to the user when the hot water storage operation is not performed is referred to as a hot water supply operation.

  The pressure reducing valve 7 has a function of decompressing low-temperature water supplied from a water supply source (not shown) and distributing it to the hot water storage circuit 41 and the hot water supply circuit 42 of the hot water storage unit 40. The water supply amount sensor 8 is a water supply source (not shown). It has a function of detecting the flow rate of the low-temperature water supplied from.

  The hot water mixing valve 10 is constituted by, for example, a three-way valve, and communicates the hot water storage tank 9 and the water refrigerant heat exchanger 2 during hot water storage operation and shuts off the hot water storage tank 9 and the hot water mixing valve 11, and during hot water operation, The hot water / water mixing valve 11 is communicated and the hot water storage tank 9 and the water / refrigerant heat exchanger 2 are shut off.

The hot water mixing valve 11 has a function of mixing low temperature water supplied from a water supply source (not shown) with high temperature hot water taken out from the hot water storage tank 9.
The hot water mixing valve 11 adjusts the flow rate of the low temperature water mixed with the high temperature hot water taken out from the hot water storage tank 9 by adjusting the valve opening, and the temperature of the hot water supplied to the user from the hot water tap 13 (hereinafter referred to as “hot water temperature”). , Referred to as hot water supply temperature).

  The water circulation pump 14 has a function of sending low-temperature water supplied from a water supply source (not shown) to the water supply side heat transfer pipe 2 b of the water refrigerant heat exchanger 2.

  The operation control device 50 includes the rotational speed of the compressor 1, the valve opening degree of the expansion valve 3, the operation / stop of the water circulation pump 14, the operation / stop of the fan motor 5, the state of the hot water mixing valve 10, and the hot water mixing valve 11. The valve opening degree is controlled to control hot water storage operation and hot water supply operation of the heat pump water heater 100.

When the heat pump water heater 100 configured as described above is operated for hot water supply, the operation control device 50 controls the hot water supply mixing valve 10 to connect the hot water storage tank 9 and the hot water mixing valve 11 and to store the hot water storage tank 9 and the water refrigerant. The heat exchanger 2 is shut off.
Moreover, the operation control apparatus 50 adjusts the valve opening degree of the hot and cold water mixing valve 11 according to a preset hot water supply temperature.
When the user opens the hot-water tap 13, hot water stored in the upper part of the hot water storage tank 9 is pushed out from the upper part of the hot water storage tank 9 toward the hot water supply mixing valve 10 by the water pressure of a water supply source (not shown).
Hot hot water pushed out from the hot water storage tank 9 flows into the hot water mixing valve 11 via the hot water supply mixing valve 10 and mixes with low temperature water supplied from a water supply source (not shown).

  Since the opening degree of the hot water mixing valve 11 is set according to the hot water supply temperature, hot hot water mixed with low temperature water by the hot water mixing valve 11 is supplied to the user from the hot water tap 13 as hot water at the hot water temperature. Is done.

On the other hand, the lower part of the hot water storage tank 9 is supplied (supplemented) with low-temperature water in an amount corresponding to the extruded hot water from a water supply source (not shown).
A boundary layer is formed between the hot hot water accumulated in the upper part of the hot water storage tank 9 and the low temperature water supplied to the lower part of the hot water storage tank 9, and the hot hot water and the low temperature water are separated without mixing. . And the inside of the hot water storage tank 9 is in a state where the upper part is higher than the boundary layer and the lower part is low.

When the heat pump water heater 100 is operated for hot water storage, the operation control device 50 controls the hot water supply mixing valve 10 to connect the hot water storage tank 9 and the water refrigerant heat exchanger 2 and to shut off the hot water storage tank 9 and the hot water mixing valve 11. .
The operation control device 50 gradually increases the rotation speed of the compressor 1 at the start of the hot water storage operation, and operates at a predetermined high-speed rotation speed (for example, 7000 rpm) in order to shorten the heating start-up time. Then, the operation control device 50 operates at a medium rotational speed by lowering the rotational speed of the compressor 1 after stable heating, and operates the compressor 1 at a rotational speed commensurate with the heating temperature according to the heat load.

  Further, the operation control device 50 drives the water circulation pump 14 to send the low-temperature water accumulated below the hot water storage tank 9 to the water supply side heat transfer tube 2 b of the water-refrigerant heat exchanger 2. The low-temperature water accumulated below the hot water storage tank 9 is heated to the boiling temperature by the high-temperature refrigerant flowing through the refrigerant-side heat transfer tube 2 a and is stored above the hot water storage tank 9 via the hot water mixing valve 10. .

Furthermore, when the hot water storage operation is performed, the operation control device 50 corresponds to the outside air temperature, the temperature of the air heat exchanger 4, the frost formation amount of the air heat exchanger 4, and the hot water storage amount (liquid storage amount) of the hot water storage tank 9. Based on the defrosting start determination means for determining the start of defrosting based on the set defrosting start determination criterion, and on the basis of the defrosting end determination criterion set corresponding to the outside air temperature and the temperature of the air heat exchanger 4 It functions as a defrosting end judging means for judging the defrosting end.
And if the operation control apparatus 50 determines the defrost start, it will defrost the heat pump water heater 100. FIG.
The amount of hot water stored in the hot water storage tank 9 indicates the amount of hot hot water accumulated in the hot water storage tank 9, and is hereinafter simply referred to as hot water storage amount.

  When the heat pump water heater 100 is defrosted, the operation control device 50 drives the compressor 1 and opens the expansion valve 3 with the maximum valve opening, and distributes a large amount of refrigerant to the air heat exchanger 4. Let Further, the operation of the fan motor 5 is stopped, and the intake of outside air into the air heat exchanger 4 is stopped. A large amount of medium temperature refrigerant flows through the air heat exchanger 4, and the frost in the air heat exchanger 4 is melted and defrosted.

Since the operation control device 50 functions as a defrost start determination unit, the operation control device 50 needs to detect the outside air temperature, the exchanger temperature, the frost formation amount of the air heat exchanger 4, and the hot water storage amount.
Therefore, the heat pump water heater 100 measures the temperature of the hot water stored in the hot water storage tank 9 by measuring the outdoor air temperature and inputting the measurement signal (outside air temperature signal) to the operation control device 50. The surface temperature of the plurality of tank thermistors 9a and the air heat exchanger 4 that inputs the measurement signal (hot water temperature measurement signal) to the operation control device 50 is measured, and the measurement signal (heat exchanger temperature signal) is used as the operation control device 50. Is provided with an air heat exchange thermistor 4a.
Hereinafter, the surface temperature of the air heat exchanger 4 measured by the air heat exchange thermistor 4a is referred to as “temperature of the air heat exchanger 4” and is referred to as the exchanger temperature.
Moreover, although mentioned later for details, the operation control apparatus 50 detects the amount of frost formation of the air heat exchanger 4 based on external temperature and exchanger temperature.

The plurality of tank thermistors 9a are preferably arranged vertically, for example, from the upper part to the lower part of the hot water storage tank 9.
When hot hot water is accumulated above the hot water storage tank 9 and low temperature water is accumulated below, the tank thermistor 9a disposed above the boundary layer between the hot water and the low temperature water adjusts the temperature of the hot water. The tank thermistor 9a, which is measured and arranged below the boundary layer, measures the temperature of the low-temperature water.

  For example, as shown in FIG. 1, five tank thermistors 9a1 to 9a5 are arranged in this order from above the hot water storage tank 9, and a boundary layer between hot and cold water is provided between the tank thermistors 9a3 and 9a4. When formed, the tank thermistors 9a1 to 9a3 measure the temperature of hot hot water, and the tank thermistors 9a4 and 9a5 measure the temperature of low temperature water.

Therefore, when the temperature measured by the tank thermistors 9a1 to 9a3 is a predetermined boiling temperature and the temperature measured by the tank thermistors 9a4 and 9a5 is lower than the predetermined boiling temperature, the operation control device 50 has the tank thermistors 9a1 to 9a1. It can be detected that hot hot water is accumulated at a position where 9a3 is disposed and low temperature water is accumulated at positions where tank thermistors 9a4 and 9a5 are disposed.
In this way, the operation control device 50 can detect the amount of hot hot water accumulated in the hot water storage tank 9, that is, the amount of hot water stored.
The number of tank thermistors 9a is not limited to five.

The operation control device 50 can detect the outside temperature measured by the outside temperature thermistor 15 based on the outside temperature signal, and the surface temperature of the air heat exchanger 4 (the exchanger) measured by the air heat exchange thermistor 4a based on the heat exchanger temperature signal. Temperature).
Then, the operation control device 50 sets the surface temperature (exchanger temperature) of the air heat exchanger 4 measured by the air heat exchange thermistor 4 a as the temperature of the air heat exchanger 4.

Further, the operation control device 50 detects (estimates) the frost formation amount of the air heat exchanger 4 based on the outside air temperature and the exchanger temperature.
The method by which the operation controller 50 detects the frost formation amount of the air heat exchanger 4 based on the outside air temperature and the exchanger temperature is not limited. For example, the relationship between the outside air temperature, the exchanger temperature, and the frost formation amount is determined. These are obtained in advance through experiments or the like and stored in a storage unit (not shown) of the operation control device 50 as a map.
The operation control device 50 reads the corresponding frost formation amount with reference to the map according to the outside air temperature measured by the outside air temperature thermistor 15 and the exchanger temperature measured by the air heat exchange thermistor 4a.
In this way, the operation control device 50 detects (estimates) the frost formation amount of the air heat exchanger 4 based on the outside air temperature and the exchanger temperature.

In the heat pump water heater 100 configured as described above, the operation control device 50 is set in advance to perform a hot water storage operation in a time zone (for example, from 23:00 to 7:00 in the next morning) where an inexpensive night discount electricity rate is applied. ing.
Hereinafter, a time zone in which the operation control device 50 performs the hot water storage operation of the heat pump water heater 100 is referred to as a hot water storage time zone Tim.
Note that the hot water storage time zone Tim is not limited to 23:00 to 7:00 the next morning, and a configuration that can be set as appropriate is preferable, and a configuration that is set appropriately by the user in accordance with the charge system of the electric power company, etc. Good.

Then, the operation control device 50 determines whether or not defrosting is necessary when the heat pump water heater 100 is operated for hot water storage during the hot water storage time period Tim. If it is determined that defrosting is necessary, the operation control device 50 defrosts the heat pump water heater 100. Configured to drive.
That is, the operation control device 50 determines the start of the defrosting operation during the hot water storage time zone Tim. Hereinafter, the determination of the start of the defrosting operation is referred to as defrosting start determination.

The operation control device 50 according to this embodiment is configured to defrost according to the outside air temperature, the exchanger temperature (the surface temperature of the air heat exchanger 4), the frost formation amount of the air heat exchanger 4, and the hot water storage amount. Defrosting start determination is made based on the start determination criteria.
Below, the operation control apparatus 50 demonstrates the method of defrost start determination based on the preset defrost start determination reference | standard.

For example, in the present embodiment, the defrosting start determination standard shown as an example in FIG. 2 is set in advance.
The defrosting start determination criteria shown in FIG. 2 are the four items of the outside air temperature, the exchanger temperature (the surface temperature of the air heat exchanger 4 (see FIG. 1)), the frost formation amount of the air heat exchanger 4, and the hot water storage amount. A determination result is set for each of the corresponding sections St1 to St5.
In addition, the numerical value shown in FIG. 2 is an example, Comprising: The numerical value of a defrost start determination criterion is not limited. The value of each item is preferably set as appropriate based on the basic performance, usage environment, and the like of the heat pump water heater 100 (see FIG. 1).
In addition, although the defrosting start determination standard shown in FIG. 2 is composed of five sections, the number of sections is not limited to five.

  The section St1 indicates a state where the outside air temperature is “5 ° C. or higher”. In this case, the determination result is set to “defrosting: no”, assuming that the air heat exchanger 4 (see FIG. 1) is not frosted and defrosting is not necessary.

The sections St2 to St5 indicate a state where the outside air temperature is “less than 5 ° C.”. In this case, the determination result is set based on the exchanger temperature.
The section St2 shows a state where the exchanger temperature is “−5 ° C. or higher”. In this case, the determination result is set to “defrosting: no”, assuming that the amount of frost formation in the air heat exchanger 4 is small and defrosting is not necessary.

Sections St3 to St5 indicate a state where the exchanger temperature is “less than −5 ° C.”. In this case, the determination result is set based on the frost formation amount of the air heat exchanger 4.
When the outside air temperature is “less than 5 ° C.” and the exchanger temperature is “less than −5 ° C.”, the operation control device 50 detects the frost formation amount of the air heat exchanger 4 based on the outside air temperature and the exchanger temperature.
The division St3 is a case where the amount of frost formation detected by the operation control device 50 is smaller than a predetermined reference value set in advance, and the determination result is set to “defrosting: no”.

The section St4 and the section St5 indicate a “large amount” state in which the frost amount of the air heat exchanger 4 is greater than a predetermined reference value. In this state, it is determined that defrosting is necessary, and the determination result is set to “defrosting: required”.
Further, in the defrosting start determination criterion according to the present embodiment, the timing for starting the defrosting operation is set based on the amount of stored hot water.
In the defrosting start determination criterion according to the present embodiment, a prescribed amount of the hot water storage tank 9 (see FIG. 1) serving as a reference for setting the timing for starting the defrosting operation is set in advance, and the hot water storage amount is equal to or more than the prescribed amount And the timing at which the defrosting operation is started when the amount of stored hot water is less than the specified amount.

This prescribed amount is preferably set as appropriate based on the heating performance of the heat pump water heater 100 (see FIG. 1) and the like.
In the defrosting start determination criterion shown in FIG. 2, “80%” is exemplified as the prescribed amount, and the timing for starting the defrosting operation is determined when the hot water storage amount is “80%” or more and less than “80%”. It is set.

  The section St4 indicates a state where the hot water storage amount is “80% or more”. In this case, the hot water storage operation for filling the hot water storage tank 9 with hot hot water may be performed in a short time, and even if the amount of frost formation is large and the efficiency of heat exchange in the air heat exchanger 4 is reduced, the influence is small. To do. Therefore, the timing for starting the defrosting operation is set so that the hot water storage operation is continued and the defrosting operation is started after the hot water storage tank 9 is filled with hot hot water and the hot water storage operation is completed. That is, the determination result is set to “start defrosting operation after hot water storage is completed”.

  The section St5 indicates a state where the amount of stored hot water is “less than 80%”. In this case, a hot water storage operation for a long time is required to fill the hot water storage tank 9 with hot hot water. And in order to avoid long-time hot water storage operation in a state where the amount of frost formation is large and the efficiency of heat exchange in the air heat exchanger 4 is reduced, the hot water storage operation is interrupted and the defrosting operation is started immediately. The timing for starting the defrosting operation is set. That is, the determination result is set to “start defrosting operation immediately”.

As described above, the present embodiment is based on the defrosting start determination criterion in which the determination result is set for each section according to the outside air temperature, the exchanger temperature, and the frost formation amount of the air heat exchanger 4 (see FIG. 1). The operation control device 50 (see FIG. 1) is configured to determine the start of defrosting.
Furthermore, when defrosting is required, that is, when the determination result is “defrosting: required”, the operation control device 50 is configured to determine the timing for starting the defrosting operation according to the amount of stored hot water.

According to this configuration, in the heat pump water heater 100 (see FIG. 1), even if the outside air temperature is low, the defrosting operation is not started unless the exchanger temperature is lower than a predetermined value.
Therefore, for example, it is possible to avoid a defrosting operation in a state where there is a low possibility that the air heat exchanger 4 (see FIG. 1) is frosted, such as immediately after the operation of the heat pump water heater 100 is started.
That is, when the possibility that the air heat exchanger 4 is frosted is low, the hot water storage operation is not interrupted, and the hot water storage tank 9 can be quickly filled with hot hot water.
In addition, when the amount of hot water storage is more than a specified amount (for example, “80% or more”), the hot water storage operation is not interrupted even if defrosting is necessary, and the hot water storage tank 9 is quickly filled with hot water. Can do.

With reference to FIG. 3, the procedure of the defrost start determination based on a defrost start determination criterion is demonstrated (refer FIG. 1, FIG. 2 suitably).
The specific numerical values shown in FIG. 3 are numerical values shown as an example in the defrosting start determination standard shown in FIG. 2, and are values set as the defrosting start determination standard in actual operation.

When the outside air temperature measured by the outside air temperature thermistor 15 is “5 ° C. or higher” (step S301 → Yes), the operation control device 50 sets the determination result as “defrosting: no” as the defrosting start determination criterion category St1. (Step S304).
In addition, when the outside air temperature is “less than 5 ° C.” (step S301 → No), when the exchanger temperature is “−5 ° C. or higher” (step S302 → Yes), the operation control device 50 determines the defrosting start determination criterion. As the classification St2, the determination result is “defrosting: no” (step S304).

Then, when the exchanger temperature is “less than −5 ° C.” (step S302 → No), the operation control device 50 detects (estimates) the frost formation amount of the air heat exchanger 4 based on the outside air temperature and the exchanger temperature. If the detected (estimated) frost formation amount of the air heat exchanger 4 is equal to or greater than a preset reference value (step S303 → Yes), the defrost start determination criteria are classified as St4 and St5. The determination result is “defrosting: required” (step S305).
On the other hand, when the detected (estimated) frost formation amount of the air heat exchanger 4 is less than the preset reference value (step S303 → No), the operation control device 50 determines the determination result as the defrost start determination criterion category St3. Is "defrosting: no" (step S304).
As described above, the operation control device 50 makes the defrost start determination based on the defrost start determination criterion.

Furthermore, when the determination result is “defrosting: required” (step S305), the operation control device 50 determines the timing for starting the defrosting operation based on the amount of stored hot water.
Therefore, the operation control apparatus 50 detects the amount of stored hot water (step S306).
As described above, the operation control device 50 detects the amount of stored hot water based on the temperature of hot water measured by the plurality of tank thermistors 9a.

  When the detected hot water storage amount is “80% or more” (step S307 → Yes), the operation control apparatus 50 sets the determination result as “defrosting start after hot water storage end” as the classification St4 of the defrosting start determination criterion ( When the amount of stored hot water is “less than 80%” (step S307 → No), the determination result is “immediately start defrosting operation” as the defrosting start determination criterion category St5 (step S309).

  For example, as shown in FIG. 1, when five tank thermistors 9a1 to 9a5 are arranged from above the hot water storage tank 9, the temperature measured by the four tank thermistors 9a1 to 9a4 from above is a predetermined boiling temperature. Yes, when the temperature measured by the tank thermistor 9a5 is lower than the predetermined boiling temperature, the operation control device 50 determines that the amount of stored hot water is “80%”.

  As described above, the operation control device 50 makes the defrost start determination based on the defrost start determination criterion, and further determines the timing for starting the defrost operation based on the hot water storage amount.

Further, when the operation control device 50 (see FIG. 1) starts the defrosting operation, the defrosting end determination is set in accordance with the operation state, the outside air temperature, and the exchanger temperature of the heat pump water heater 100 (see FIG. 1). The end of defrosting is determined based on the criteria.
Hereinafter, the determination of completion of defrosting is referred to as defrosting determination.
In the present embodiment, the operation state of the heat pump water heater 100, which is an element of the defrosting end determination criterion, will be simply referred to as an operation state hereinafter, and “after hot water storage operation (suspended)” and “after the hot water storage operation has ended. Have two states.

For example, in the present embodiment, the defrosting end determination criterion shown in FIG. 4 as an example is set in advance.
As shown in FIG. 4, the defrosting end determination criterion according to the present embodiment is divided into E1 to E5 according to the operation state and the outside air temperature, and the defrosting end temperature is set for each section, and the defrosting end temperature is set. The determination result according to is set.
The defrosting end temperature is a temperature that serves as a guideline for determining that the defrosting has ended. In this embodiment, the defrosting end temperature is determined based on the exchanger temperature.

In addition, the numerical value shown in FIG. 4 is an example like the defrosting start criterion shown in FIG. 2, and the numerical value of the defrosting end criterion is not limited. The value of each item is preferably set as appropriate based on the basic performance, usage environment, and the like of the heat pump water heater 100 (see FIG. 1).
In addition, although the defrosting end determination criterion shown in FIG. 4 is composed of five sections, the number of sections is not limited to five.

The divisions E1 to E4 are cases where the operation state is “during hot water storage operation (interruption)”.
That is, it shows a state where the hot water storage operation of the heat pump water heater 100 (see FIG. 1) is interrupted and the defrosting operation is started.
In this state, the defrosting end temperature is set for each of the sections E1 to E4 corresponding to the outside air temperature.

The section E1 is a case where the outside air temperature is “0 ° C. or higher”. In this case, if the exchanger temperature is “4 ° C. or higher”, the air heat exchanger 4 can be defrosted. When the defrost end temperature is “4 ° C. or higher”, the determination result is “defrost: completed”. And
The section E2 is a case where the outside air temperature is “−10 ° C. or higher and lower than 0 ° C.”. In this case, if the exchanger temperature is “5 ° C. or higher”, the air heat exchanger 4 can be defrosted, and when the defrost end temperature is “5 ° C. or higher”, the determination result is “defrost: end”. And
The section E3 is a case where the outside air temperature is “−20 ° C. or higher and lower than −10 ° C.”. In this case, if the exchanger temperature is “6 ° C. or higher”, the air heat exchanger 4 is defrosted, and the determination result is “defrost: completed” when the defrost end temperature is “6 ° C. or higher”. And
The section E4 is a case where the outside air temperature is “less than −20 ° C.”. In this case, if the exchanger temperature is “7 ° C. or higher”, the air heat exchanger 4 is defrosted, and when the defrost end temperature is “7 ° C. or higher”, the determination result is “defrost: completed”. And

Section E5 is a case where the operation state is “after the hot water storage operation is completed”.
That is, the defrosting operation is started after the hot water storage operation of the heat pump water heater 100 (see FIG. 1) is completed.
In this state, the defrosting end temperature (exchanger temperature) is set to one predetermined temperature that is determined in advance.
The predetermined temperature is preferably set as appropriate based on the usage environment of the heat pump water heater 100 (see FIG. 1).
The defrosting end determination criterion shown in FIG. 4 illustrates “4 ° C.” as the predetermined temperature.
In section E5, if the exchanger temperature is “4 ° C. or higher” regardless of the outside air temperature, the air heat exchanger 4 is defrosted, and the defrosting end temperature is “4 ° C. or higher”. The determination result is “defrosting: completed”.
Note that if the determination result is not “defrosting: completed”, the operation control device 50 sets the determination result to “defrosting: not completed”.

  For example, the exchanger temperature measured by the air heat exchanger thermistor 4a (see FIG. 1) is the surface temperature of a representative point of the air heat exchanger 4 (see FIG. 1), and the exchanger temperature is low when the outside air temperature is low. When the defrosting is finished in the state, the surface temperature other than the representative point of the air heat exchanger 4 where the air heat exchanger thermistor 4a measures the exchanger temperature is low, and frost may remain. In view of this, in the categories E1 to E4 of the defrosting end determination criteria, the lower the outside air temperature, the higher the exchanger temperature when determining “defrosting: end”, so that the defrosting can be reliably performed. That is, the defrosting end temperature is set higher as the outside air temperature is lower.

In addition, in the sections E1 to E4, the operation state is “during hot water storage operation (interrupted)”, and the hot water storage operation is resumed immediately after the defrosting operation is completed.
In this case, as the outside air temperature is lower, the exchanger temperature rapidly decreases after the hot water storage operation is restarted, and the possibility that the water in which the frost has melted refreezes and frosts increases.
Therefore, when the operation state is “hot water storage operation (interrupted)”, the defrosting end temperature is set high, and after the hot water storage operation is restarted, the air heat exchanger 4 (see FIG. 1) is lowered to a low temperature at which it is frozen again. It is configured so that it is difficult to prevent frost due to refreezing after resuming hot water storage operation.

On the other hand, in the defrosting end criterion C5, the operation state is “after the hot water storage operation is completed”, and the heat pump water heater 100 (see FIG. 1) does not resume the hot water storage operation immediately after the defrosting operation. Therefore, the exchanger temperature does not drop rapidly after completion of the defrosting operation, and there is no possibility that the water in which the frost is melted is frozen again.
Further, after the defrosting operation, the heat pump water heater 100 does not perform the hot water storage operation until the hot water storage time zone Tim on the next day.
Even if there is a slight residual frost in the air heat exchanger 4 of the heat pump water heater 100, the residual frost melts in the daytime when the outside air temperature is high, so that the hot water storage operation in the hot water storage time period Tim of the next day is not hindered.

Therefore, in the category E5 of the defrosting end determination criterion according to the present embodiment, the defrosting end temperature (exchanger temperature) at which the determination result is “defrosting: end” is set to a low value such as “4 ° C. or higher”. it can.
Thus, when the defrosting end temperature is set to a low value, it is not necessary to raise the exchanger temperature at the time of the defrosting operation, so that the time required for the defrosting operation is shortened and the power consumption during the defrosting operation is suppressed. be able to.

With reference to FIG. 5, the procedure of the defrost end determination based on a defrost end determination criterion is demonstrated (refer FIG. 1, FIG. 4 suitably).
In addition, the specific numerical value shown in FIG. 5 is a numerical value shown as an example in the defrosting end determination standard shown in FIG. 4, and is a numerical value set as the defrosting end determination standard in actual operation.

  When the operation state is not “hot water storage operation (interruption)” (step S501 → No), that is, “after hot water storage operation is completed”, the operation control device 50 determines the exchanger temperature measured by the air heat exchange thermistor 4a. Is “4 ° C. or higher” (step S502 → Yes), the defrosting end determination criterion is category E5, and the determination result is “defrosting: end” (step S508), but the exchanger temperature is “4 ° C.”. If “less than” (step S502 → No), the determination result is “defrosting: not completed” (step S507).

  On the other hand, when the operation state of the heat pump water heater 100 is “hot water storage operation (interrupted)” (step S501 → Yes), if the outside air temperature is “0 ° C. or higher” and the exchanger temperature is “4 ° C. or higher”. (Step S503 → Yes) As the defrosting end determination criterion category E1, the determination result is “defrosting: end” (step S508).

  When the outside air temperature and the exchanger temperature do not satisfy the condition of the category E1 of the defrosting end determination criterion (step S503 → No), the operation controller 50 determines that the outside air temperature is “−10 ° C. to 0 ° C.” and the exchanger temperature. Is “5 ° C. or higher” (step S504 → Yes), the determination result is “defrosting: end” as the defrosting end determination criterion category E2 (step S508).

  When the outside air temperature and the exchanger temperature do not satisfy the condition of the category E2 of the defrosting end determination criterion (step S504 → No), the operation control device 50 uses the exchanger at the outside air temperature of “−20 ° C. to −10 ° C.”. If the temperature is “6 ° C. or higher” (step S505 → Yes), the determination result is “defrosting: end” as the defrosting end determination criterion category E3 (step S508).

  When the outside air temperature and the exchanger temperature do not satisfy the condition of the category E3 of the defrosting end determination criterion (step S505 → No), the operation controller 50 determines that the outside air temperature is “less than −20 ° C.” and the exchanger temperature is “ If it is “7 ° C. or higher” (step S506 → Yes), the determination result is “defrosting: end” as the defrosting end determination criterion category E4 (step S508).

  When the outside air temperature and the exchanger temperature do not satisfy the condition of the category E4 of the defrosting end determination criterion (step S506 → No), the operation control device 50 sets the determination result to “defrosting: not completed” (step S507). ).

  As described above, the operation control device 50 determines the end of defrosting based on the defrosting end determination criterion in which the defrosting end temperature is set for each category according to the operating state and the outside air temperature measured by the outside temperature thermistor 15. .

The operation control device 50 according to the present embodiment (see FIG. 1) determines the start of defrosting when the heat pump water heater 100 (see FIG. 1) is stored in the hot water storage time zone Tim, and is set as necessary. Start defrosting operation.
When the defrosting operation is started, the operation control device 50 determines the end of the defrosting operation by the defrosting end determination and ends the defrosting operation.

  Hereinafter, a procedure in which the operation control device 50 (see FIG. 1) performs the defrosting operation of the heat pump water heater 100 (see FIG. 1) will be described mainly with reference to FIG. 6 (see FIGS. 1 to 5 as appropriate).

  For example, the operation control device 50 periodically executes the procedure shown in FIG. 6 to perform a hot water storage operation of the heat pump water heater 100 during a preset hot water storage time period Tim, and further performs a defrosting operation as necessary.

If it is not the hot water storage time zone Tim (step S1 → No), the operation control device 50 performs the hot water supply operation of the heat pump water heater 100 (step S2), but if it is the hot water storage time zone Tim (step S1 → Yes), the hot water storage operation is performed. (Step S3), and further, defrosting start determination is made (step S4).
The operation control device 50 performs the defrosting start determination according to the procedure illustrated in FIG. 3 based on the defrosting start determination criterion illustrated in FIG. 2.

  Then, when the determination result of the defrost start determination is not “defrost: required” but “defrost: no” (step S4 → No), the operation control device 50 continues the hot water storage operation. That is, the operation control device 50 repeats the defrosting start determination procedure (step S4) while the hot water storage operation is not completed (step S5 → No), and when the hot water storage is completed (step S5 → Yes), The operation is terminated (step S6), and a hot water supply operation is performed (step S7).

  Thus, while hot water storage is not completed (step S5 → No), by repeating the defrosting start determination procedure (step S4) while performing hot water storage operation, defrosting is required during hot water storage operation. Also, the defrosting operation can be started as necessary.

  The operation control device 50 may store hot water when, for example, the temperature of the hot water measured by the tank thermistor 9a (tank thermistor 9a5 shown in FIG. 1) disposed at the lowermost part of the hot water storage tank 9 is a predetermined boiling temperature. It is determined that the tank 9 is filled with hot hot water, and the end of hot water storage is determined.

  On the other hand, when the determination result of the defrost start determination is “Defrost: Necessary” (Step S4 → Yes) and not “Defrost operation start immediately” (Step S8 → No), that is, the determination result of the defrost start determination Is “start defrosting operation after hot water storage is completed”, operation control device 50 continues the hot water storage operation until hot water storage is completed (step S9 → No). And if hot water storage is complete | finished (step S9-> Yes), hot water storage operation will be complete | finished (step S10) and defrost operation will be started (step S11).

  After starting the defrosting operation (step S11), the operation control device 50 makes a defrosting end determination according to the procedure shown in FIG. 5 based on the defrosting end determination criterion shown in FIG. Then, the defrosting operation is performed until the determination result of the defrosting end determination is “defrosting: end” (step S12 → No), and when the determination result of the defrosting end determination is “defrosting: end” (step S12). → Yes), the defrosting operation is terminated (step S13), and the hot water supply operation is performed (step S7).

Returning to step S8, when the determination result of the defrosting start determination is “immediately defrosting operation start” (step S8 → Yes), the operation control device 50 interrupts the hot water storage operation (step S14) and starts the defrosting operation. (Step S15).
And the driving | operation control apparatus 50 determines completion | finish of defrost based on the procedure shown in FIG. 5 based on the defrost completion | finish determination criteria shown in FIG. 4 (step S16).

  The operation control device 50 performs the defrosting end determination according to the procedure shown in FIG. 5 based on the defrosting end determination criterion shown in FIG. 4 and performs the defrosting operation until the determination result becomes “defrosting: end” (step S16). → No). Then, when the determination result of the defrosting end determination is “defrosting: end” (step S16 → Yes), the defrosting operation is ended (step S17).

Further, the operation control device 50 restarts the hot water storage operation (step S18), performs hot water storage operation while the hot water storage is not completed (step S5 → No), and ends hot water storage operation when the hot water storage is completed (step S5 → Yes). Then (step S6) hot water supply operation is performed (step S7).
In addition, when the hot water storage operation is resumed after the end of the defrosting operation (step S17) (step S18), the hot water storage end may be determined without returning to step S4 while the hot water storage is not completed (step S5 → No).

As described above, the heat pump water heater according to the present embodiment has priority when the amount of hot water stored in the hot water storage tank is equal to or greater than a predetermined specified amount (for example, 80%) even when defrosting is necessary. The hot water storage operation can be performed, and the excellent effect that the hot water storage can be completed quickly is achieved.
Moreover, even if the outside air temperature is less than a predetermined value (for example, 5 ° C.), the exchanger temperature (the surface temperature of the air heat exchanger) that is the temperature of the air heat exchanger is not less than a predetermined value (for example, −5 ° C.). Since it is determined that no defrosting is necessary, for example, when the heat pump water heater has only started for a short time after starting operation and the air heat exchanger is not frosted, the defrosting operation is performed. There is an excellent effect that it can be avoided.

Further, when the defrosting operation is performed with the hot water storage operation interrupted, the end of the defrosting is determined according to the outside air temperature and the exchanger temperature.
As described above, when the outside air temperature is low, the temperature of the exchanger rapidly decreases after resuming the hot water storage operation, and there is a possibility that the water in which the frost is melted in the defrosting operation is frozen again.
Therefore, in this embodiment, when the outside air temperature is low, the exchanger temperature at the end of defrosting is increased to prevent refreezing after restarting the hot water storage operation.
As described above, in the present embodiment, when the hot water storage operation is interrupted and the defrosting operation is performed, the refrosting after restarting the hot water storage operation can be prevented by ending the defrosting operation according to the outside air temperature and the exchanger temperature. There is an excellent effect.

Moreover, when performing defrost operation after completion | finish of hot water storage operation, it was set as the structure which complete | finishes defrost operation in a state with a low exchanger temperature.
With this configuration, when the defrosting operation is performed after the hot water storage operation is completed, it is not necessary to increase the exchanger temperature, and the time required for the defrosting operation can be shortened and the power consumption during the defrosting operation can be suppressed. There is an effect.

In addition to the configuration used to supply hot water stored in a tank to a hot water supply terminal such as a hot water tap, the heat pump water heater also uses boiling water stored in the tank as a heat medium. In this case, the heat medium stored in the tank may not be hot water as long as it is a liquid.
The present invention can also be applied to the heat pump water heater configured as described above, and the hot water storage tank 9 of the heat pump water heater 100 shown in FIG. 1 may be a tank that stores liquid as a heat medium.
In addition, as a method of using a high-temperature liquid stored in a tank as a heat medium, a method of heating water supplied from a water supply source and supplying the heated water (hot water) to a hot water supply terminal can be considered.

  Further, the heat pump water heater according to the present embodiment is configured by combining a heat pump unit and a hot water storage unit, but the present invention is also applied to a so-called integrated heat pump water heater in which a tank and a heat source are integrally provided. In this case, the heat source provided integrally with the tank can be specified as the heat pump unit.

  In the heat pump water heater according to the present embodiment, the low-temperature hot water (low-temperature liquid) sent to the heat pump unit is taken out from below the tank, but the low-temperature hot water sent to the heat pump unit does not pass through the tank. The structure taken out directly from a water supply pipe may be sufficient.

4 Air heat exchanger 9 Hot water storage tank (tank)
30 Heat pump unit (heat pump part)
31 Heat pump refrigerant circuit 40 Hot water storage unit (liquid storage unit)
41 Hot water storage circuit 42 Hot water supply circuit 50 Operation control device (defrosting start determining means, defrosting end determining means)
100 heat pump water heater

Claims (4)

A heat pump unit serving as a heat source for boiling liquid to a predetermined boiling temperature;
A liquid storage unit for storing the liquid at the boiling temperature in a tank,
In the heat pump water heater having a defrosting start determining means for determining the start of a defrosting operation for defrosting the air heat exchanger provided in the heat pump unit and a defrosting end determining means for determining the end of the defrosting operation,
The defrosting start determining means is configured to determine the defrosting start based on a defrosting start determination criterion in which a determination result is set for each category according to an outside air temperature, a temperature of the air heat exchanger, and a frosting amount of the air heat exchanger. Determine the start of frost operation,
The defrosting end determination means determines the end of the defrosting operation based on a defrosting end determination criterion in which a defrosting end temperature is set for each section according to the outside air temperature. In the defrosting start determination criterion, the timing for starting the defrosting operation is set corresponding to the temperature of the air heat exchanger and the amount of liquid stored in the tank,
The heat pump water heater according to claim 1, wherein the defrosting start determining means determines a timing for starting the defrosting operation based on the defrosting start determination criterion. The timing for starting the defrosting operation is as follows:
If the amount of liquid stored in the tank is greater than or equal to a predetermined amount, the defrosting operation is set to start after the hot water storage operation to boil the liquid is completed,
The heat pump water heater according to claim 2, wherein when the amount of liquid stored in the tank is less than the specified amount, the hot water storage operation is interrupted and the defrosting operation is started. The defrosting end criterion is:
The defrosting end temperature when the hot water storage operation is interrupted and the defrosting operation is started is set for each section according to the outside air temperature,
The heat pump water heater according to claim 3, wherein the defrosting end temperature when the defrosting operation is started after the hot water storage operation is finished is set to one predetermined temperature.

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