JP2003185308A - Heat pump type hot-water supplying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an open air temperature detector near an outdoor heat exchanger so as not to erroneously detect an open air temperature immediately after a termination of defrosting operation and to restart a regular hot-water supply operation promptly in the heat pump type hot-water supplying apparatus which performs capacity control of a compressor and the opening control of an electric expansion valve corresponding to the open air temperature detected by the detector. <P>SOLUTION: When an evaporator temperature increases to the defrosting termination temperature, a defrost circuit is closed, and an operation of an outdoor fan is resumed. Furthermore, a temporary hot-water supply operation which operates a compressor by maintaining the capacity of the compressor and the opening of the electric expansion valve in a fixed state is performed, and the regular hot-water supply operation is resumed after a predetermined period of time. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type hot water supply apparatus, and more particularly to operation control in a heat pump type hot water supply apparatus.

[0002]

2. Description of the Related Art Generally, a heat pump type hot water supply apparatus evaporates by exchanging heat with a compressor, a high pressure side heat exchanger for heating hot water by discharge gas of the compressor, an electric expansion valve, and outside air blown by an outdoor blower. It is equipped with a refrigerant circuit in which outdoor heat exchangers acting as a container are sequentially connected. The outdoor heat exchanger (evaporator) of the refrigerant circuit frosts when the outside air temperature decreases. For this reason, the heat pump hot water supply apparatus is provided with a defrost circuit for removing the frost of the outdoor heat exchanger (evaporator), and performs the defrost operation in which the defrost circuit is operated.

The defrost circuit is a hot gas bypass circuit for bypassing hot gas on the discharge side of the compressor to the inlet side of the outdoor heat exchanger. The defrost operation is usually performed by operating the compressor, opening the hot gas bypass circuit, and stopping the outdoor blower. In addition, the defrost operation control determines whether or not a predetermined amount of frost has occurred and whether or not defrost has been completed, depending on whether or not the evaporator temperature has reached a predetermined value. That is,
When the evaporator temperature reaches the defrosting start temperature (for example, -7 ° C), it is determined that the frost amount is equal to or more than a predetermined amount, and when the evaporator temperature reaches the defrosting end temperature (for example, 12 ° C), the defrosting occurs. I thought it was completed.

On the other hand, the hot water supply load increases as the outside air temperature decreases. Therefore, the operation control during the steady hot water supply operation in the conventional heat pump type hot water supply apparatus responds to the decrease of the outside air temperature, and performs the compressor capacity control so as to increase the capacity of the compressor according to a predetermined standard. Was there. Further, the opening degree of the electric expansion valve is controlled so as to meet the operating conditions at this time. The outside air temperature was detected by an outside air temperature detector provided near the outdoor heat exchanger and on the outside air intake side.

[0005]

However, in the case where the defrost operation control is performed as described above, and the capacity control of the compressor and the opening degree control of the electric expansion valve are performed during the steady hot water supply operation, immediately after the completion of the defrost operation, Even if the outside air temperature is low (for example, 5 ° C. or lower), the temperature of the outdoor heat exchanger is equal to the temperature at the time of completion of defrost (for example, 12).
℃). Further, since the outdoor blower is not operated during the defrost operation, the outdoor air temperature detector is heated by the outdoor heat exchanger located in the vicinity when the defrost operation ends. Therefore, there is a possibility that the temperature detected by the outside air temperature detector immediately after the end of the defrost operation may be detected higher than the actual outside air temperature. Further, there is a fear that the return to the steady hot water supply operation may be delayed due to this erroneous detection.

The present invention has been made by paying attention to the problems existing in such a conventional technique, and an outdoor air temperature detector is provided in the vicinity of the outdoor heat exchanger and detected by this detector. In the one that controls the capacity of the compressor and the opening degree of the electric expansion valve according to the outside air temperature, the outside air temperature detector does not erroneously detect the outside air temperature immediately after the defrost operation ends, and the steady hot water supply operation is restarted promptly. The purpose is to enable.

[0007]

In order to achieve the above object, a heat pump hot water supply apparatus of the present invention is a compressor, a high pressure side heat exchanger for heating hot water by discharge gas from the compressor, A refrigerant having at least an electric expansion valve, a main circuit in which an outdoor heat exchanger that sequentially exchanges heat with the outside air blown by an outdoor blower and acts as an evaporator is connected, and a defrost circuit that allows hot gas to flow to the outdoor heat exchanger. The circuit, an evaporator temperature detector that detects the surface temperature of the outdoor heat exchanger as the evaporator temperature, and the outside air installed near the outdoor heat exchanger so as to detect the temperature of the outside air drawn into the outdoor heat exchanger. Until the evaporator temperature detected by the temperature detector and the evaporator temperature detector falls to the defrost start temperature preset as the defrost start value of the outdoor heat exchanger, the outside air temperature detector Perform a steady hot water supply operation that controls the capacity of the compressor and the opening degree of the electric expansion valve according to a predetermined standard corresponding to the outside air temperature that is output, and the evaporator temperature detected by the evaporator temperature detector becomes the defrost start temperature. When the temperature drops, the outdoor blower is stopped and the defrost circuit is opened to perform the defrost operation to operate the compressor. During this defrost operation, the evaporator temperature detected by the evaporator temperature detector is changed to the outdoor heat exchange. When the defrosting end temperature preset as the defrosting completion value of the air conditioner is reached, the defrosting circuit is closed to stop the defrosting operation, and the operation of the outdoor blower is restarted.
The operation control device includes a provisional hot water supply operation in which the compressor is operated with the capacity of the compressor and the opening degree of the electric expansion valve as predetermined values, and the steady hot water supply operation is restarted after a predetermined time has elapsed.

According to this structure, the evaporator temperature detector is affected by the temperature of the outdoor heat exchanger immediately after the end of the defrost operation during the temporary operation of rotating the outdoor blower after the end of the defrost operation. Is excluded, and it becomes possible to detect a substantially accurate outside temperature. As a result, it becomes possible to restart the steady hot water storage operation promptly after the provisional operation is completed without erroneously detecting the outside air temperature.

Further, the compressor may be driven by an inverter, and the compression function force may be controlled by changing an operating frequency by an inverter.

According to this structure, it is possible to finely control the compression function force which is suitable for the hot water supply operation condition.
An efficient hot water supply operation can be performed.

Further, the operation control device may be arranged such that the outside air temperature is detected by the outside air temperature detector every time a steady hot water supply operation elapses for a certain period of time.

According to this structure, even if the outside air temperature fluctuates up and down in a short time during the steady hot water supply operation, such a short time up and down change is not detected. The capacity control of the machine and the opening control of the electric expansion valve can be stably performed.

The operation control device can also correct the defrosting start temperature based on the outside air temperature measured at regular intervals.

Since the evaporation temperature of the outdoor heat exchanger changes when the outside air temperature changes, the frost amount of the outdoor heat exchanger varies depending on the outside air temperature even if the evaporator temperature is the same. Therefore, the configuration of the present invention makes it possible to more accurately detect frost.

When restarting the steady hot water supply operation after the provisional operation is completed, the operation control device detects the outside air temperature, and according to the predetermined standard, the capacity of the compressor and the opening of the electric expansion valve corresponding to the outside air temperature. The temperature can be set and the timekeeping for detecting the outside air temperature can be started at regular intervals.

According to this structure, the capacity of the compressor and the opening degree of the electric expansion valve are set according to a normal standard from the beginning of the restart of the steady hot water supply operation. Further, a fixed time interval for newly detecting the outside air temperature at fixed intervals is newly started. Therefore, after the provisional operation is completed, the outside air temperature is not detected again in a short time, and the stable steady hot water supply operation can be promptly performed.

Further, the operation control device may set the capacity of the compressor and the opening degree of the electric expansion valve during the temporary operation to the state during the steady hot water supply operation immediately before the defrost operation.

With this structure, a large difference in outside air temperature is not expected before and after the defrost operation.
The provisional hot water supply operation will be performed under substantially the same conditions as the compression function force and the opening degree of the electric expansion valve during the next steady hot water supply operation,
The transition to the steady hot water supply operation will be performed smoothly.

Further, the operation control device may operate the compressor in the defrosting operation at a capacity higher than that in the steady hot water supply operation immediately before the defrosting operation.

According to this structure, the heat on the high pressure side of the compressor is immediately sent to the evaporator during the defrosting operation.
The defrost operation time can be shortened and the steady hot water supply operation can be quickly returned to.

In the defrosting operation, the operation control device forcibly terminates the defrosting operation when the temperature detected by the evaporator temperature detector does not reach the defrosting end temperature within a certain time. Means may be included.

According to this structure, even if the evaporator temperature detector malfunctions for some reason, the return to the steady hot water supply operation is guaranteed.

Further, in the operation control device, the forcing means may be constituted by a timer.

According to this structure, the compulsory unit can be composed of a simple timer.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram of a hot water supply device according to an embodiment of the present invention. As shown in FIG. 1, the hot water supply device according to the first embodiment includes a refrigerating device 1,
The hot water supply unit 2 and the control device 3 are provided. In this embodiment, the control device 3 is installed inside the refrigeration system 1. Further, the refrigerating apparatus 1 and the hot water supply unit 2 are connected by connecting water pipes 5 and 6.

The refrigeration system 1 includes an inverter-driven two-stage compressor 11, a high-pressure side heat exchanger 12 for heating hot water with discharge gas refrigerant, an electric expansion valve 13, an outdoor heat exchanger 14 acting as an evaporator, and an accumulator. A closed circuit (refrigerant circuit) in which 15 are sequentially connected is provided. Inside this refrigerant circuit,
Carbon dioxide (CO ₂ ) which is a natural refrigerant is filled so that it is operated in a supercritical refrigeration cycle. Note that typical natural refrigerants for refrigeration and air conditioning include hydrocarbons (HC: propane, isobutane, etc.), ammonia, air, and carbon dioxide. However,
As the refrigerant characteristics, hydrocarbon and ammonia have high energy efficiency, but they have problems of flammability and toxicity, and air has a problem of low energy efficiency except in the ultralow temperature range. On the other hand, carbon dioxide is safe without combustibility and toxicity.

The two-stage compressor 11 is developed for a supercritical refrigeration cycle, and includes a low-stage side compression mechanism portion 11a, a high-stage side compression mechanism portion 11b, and these compression mechanism portions 11a and 11b in a closed housing. It has a built-in inverter drive type electric motor 11c for driving. In addition, the discharge side of the low-stage side compression mechanism portion 11a and the suction side of the high-stage side compression mechanism portion 11b are connected by an intermediate communication pipe 11d arranged outside the compressor housing, and the sealed housing internal space is
It is filled with the intermediate pressure gas, that is, the discharge gas of the low stage side compression mechanism portion 11a. It should be noted that the reason why the pressure inside the sealed housing is intermediate is that the force acting on each part of each compressor and the pressure difference between the inside and outside of the sealed housing are kept within an appropriate range, and a large force acts. This makes it possible to provide a highly reliable, low vibration, low noise, and highly efficient compressor. Further, a discharge gas temperature detector 34 is provided in the discharge gas pipe of the compressor (the discharge pipe 18 of the high-stage compression mechanism section 11b).

The high-pressure side heat exchanger 12 is supplied with water from a refrigerant heat exchange tube 12a for introducing the high-pressure refrigerant discharged from the high-stage side compression mechanism portion 11b and a hot water storage tank 21 arranged in the hot water supply unit 2. And a water heat exchange tube 12b for introducing hot water to be supplied, and both are formed in a heat exchange relationship. Therefore, the high-stage compression mechanism section 1
The high-temperature and high-pressure refrigerant gas discharged from 1b is the hot water storage tank 2
It is cooled by the hot water supplied from the hot water 1, and this hot water is heated by the heat generated by the high-temperature high-pressure refrigerant.

The electric expansion valve 13 decompresses the high pressure gas refrigerant cooled by the high pressure side heat exchanger 12, and is driven by a pulse motor. The opening degree is controlled by the control device 3 described later.

The outdoor heat exchanger 14 heat-exchanges the low pressure gas-liquid mixed refrigerant decompressed by the electric expansion valve 13 with the outside air as a heat source medium to vaporize the refrigerant. The outdoor heat exchanger 14 is provided with an outdoor blower 14a. Further, the outdoor heat exchanger 14 is provided with an evaporator temperature detector 31. Evaporator temperature detector 31
Is for indirectly detecting the amount of frost (the amount of frost) by a change in the evaporator temperature, and detects the surface temperature of the outdoor heat exchanger 14 as the evaporator temperature. An outdoor air temperature detector 32 that detects the outdoor air temperature is provided near the outdoor air intake side of the outdoor heat exchanger 14.

The hot water supply unit 2 includes a hot water storage tank 21, a hot water circulation pump 22, a hot water supply pipe 23, and a water supply pipe 24. The upper and lower parts of the hot water storage tank 21 are connected to the water heat exchange tube 12b by a hot water circulation circuit P including communication water pipes 5 and 6. Further, in the hot water storage tank 21, the hot water temperature becomes higher as it goes up due to the difference in gravity. Therefore, hot water circulation is performed so that water having a low temperature in the lower portion of the hot water storage tank 21 is fed to the water heat exchange tube 12b and water having a high temperature heated by the water heat exchange tube 12b is guided to the upper portion of the hot water storage tank 21. While the circuit P is formed, the hot water circulating pump 22 is provided in the hot water circulating circuit P.
Is attached. The hot water temperature in the upper part of the hot water storage tank 21, that is, the heating temperature, is measured by the hot water temperature detector 33 provided in the upper part of the hot water storage tank 21.

The hot water supply pipe 23 is for supplying hot water to a hot water faucet, a bathtub, etc., and is connected to the upper part of the hot water storage tank 21 so that the hot water of high temperature in the hot water storage tank 21 can be supplied. The hot water supply circuit has an on-off valve 2
5 is attached. The water supply pipe 24 is capable of constantly supplying tap water into the hot water storage tank 21, and is connected to the bottom of the hot water storage tank 21 via a check valve 26 and a pressure reducing valve 27.

The control device 3 includes an operation switch (not shown).
When the is operated, the operation start command is transmitted, and the operation of the heat pump hot water supply device is controlled as follows. That is, until the evaporator temperature detected by the evaporator temperature detector 31 decreases to the defrost start temperature preset as the defrost start value of the outdoor heat exchanger 14, the outside air temperature detected by the outside air temperature detector 32. A steady hot water supply operation is performed in which the capacity control of the two-stage compressor 11 and the opening degree control of the electric expansion valve 13 are performed according to a predetermined standard corresponding to the temperature, and the evaporator temperature detector 3
When the evaporator temperature detected by 1 drops to the defrosting start temperature, it is determined that the frost amount of the outdoor heat exchanger 14 has reached the predetermined value, and the defrost operation is performed. Further, during the defrost operation, when the evaporator temperature detected by the evaporator temperature detector 31 rises to the defrosting end temperature preset as the defrost completion value of the outdoor heat exchanger 14, the defrost operation is stopped. Then, the operation of the outdoor blower 14a is restarted, and the provisional hot water supply operation is performed in which the capacity of the two-stage compressor 11 and the opening degree of the electric expansion valve 13 are set to predetermined values to operate the two-stage compressor 11. Then, after performing the temporary hot water supply operation for a predetermined time, the steady hot water supply operation is performed.

As an element constituting the defrost device, the refrigerant circuit is provided with a defrost circuit consisting of a first bypass circuit 16 and a second bypass circuit 17.
The first bypass circuit 16 includes a discharge pipe 18 of the high-stage compression mechanism portion 11b and a pipe on the outdoor heat exchanger inlet side (that is, a pipe connecting the electric expansion valve 13 and the outdoor heat exchanger 14) 19.
Is provided between the first and second solenoid valves 16a
Is provided. On the other hand, in the second bypass circuit 17, the discharge side of the low-stage compression mechanism section 11a is connected to the high-stage compression mechanism section 11a.
It is provided between the intermediate communication pipe 11d connected to the suction side of b and the pipe 19 on the outdoor heat exchanger inlet side, and a second electromagnetic opening / closing valve 17a is provided midway. In this case, since the intermediate communication pipe 11d is arranged outside the compressor housing, the second bypass circuit 17 can be easily connected.

The operation of the heat pump type hot water supply apparatus configured as described above will be described. First, the refrigeration cycle during the steady hot water supply operation will be described with reference to the Mollier diagram of FIG. The flow of the refrigerant during the steady hot water supply operation is as shown by the solid line arrow in FIG.

The low-stage side compression mechanism portion 11a constituting the two-stage compressor 11 has a low-pressure gas (r) from the accumulator 15.
1) is inhaled and compressed to an intermediate pressure (r2). The gas refrigerant (r2) compressed to the intermediate pressure is the intermediate communication pipe 1
1d introduced into the housing of the two-stage compressor 11,
After being slightly cooled in this housing (r3), it is sucked into the high-stage compression mechanism 11b (r3), compressed to a supercritical pressure and sent to the high-pressure heat exchanger 12 (r4). This high-pressure gas (r4) exchanges heat with the hot water supplied from the hot-water storage tank 21 in the high-pressure side heat exchanger 12, the high-pressure refrigerant itself is cooled (r5), and the hot-water is heated and heated.
Returned to the top.

The high pressure gas refrigerant (r5) cooled by the high pressure side heat exchanger 12 is decompressed by the electric expansion valve 13 and becomes a gas-liquid mixed gas refrigerant and is sent to the outdoor heat exchanger 14 (r6).
Gas-liquid mixed gas refrigerant (r6) sent to the outdoor heat exchanger 14.
Is heat-exchanged with the outside air, pumps up heat from the outside air and is vaporized, and passes through the accumulator 15 and the low-stage compression mechanism portion 11 a
Inhaled into. The accumulator 15 prevents the refrigerant accumulated in the low-pressure side circuit portion from being sucked into the compressor when the refrigeration cycle device is started.

By the above refrigeration cycle, the amount of heat pumped from the outside air and the amount of heat equivalent to the amount of work in the two-stage compressor 11 are radiated by the high-pressure heat exchanger 12, and the amount of heat supplied from the hot water storage tank 21 The water is heated and becomes hot water, which is stored from above the hot water storage tank 21.

Next, the flow of the refrigerant during the defrost operation will be described. The wavy arrow in FIG. 1 indicates the flow of the refrigerant during this defrost operation. If the steady hot water supply operation is continued in a state where the outside air temperature is low, the outdoor heat exchanger 1 gradually
Frost adheres to 4. When the amount of frost becomes a certain amount, the evaporator temperature (surface temperature of the outdoor heat exchanger 14) falls to a defrost start temperature preset as the defrost start value of the outdoor heat exchanger 14. The evaporator temperature is detected by the evaporator temperature detector 31. When the temperature detected by the evaporator temperature detector 31 reaches the defrosting start temperature, the controller 3 issues a defrost command. This defrost command causes 2
Under the situation where the operation mode during the steady hot water supply operation such as the operation of the single-stage compressor 11, the operation of the outdoor blower 14a, and the supply of the hot water from the hot water storage tank 21 to the high-pressure heat exchanger 12 is continued, the first bypass circuit The first electromagnetic on-off valve 16a in 16 and the second electromagnetic on-off valve 17a in the second bypass circuit 17 are opened.

In this way, the first and second solenoid on-off valves 16
a, 17a are opened, the solenoid on-off valves 16a, 1
Since the refrigerant flow resistance of 7a is set to be small, there is almost no difference in pressure between high and low as in the steady hot water supply operation,
The high and low pressures are in a substantially balanced state. Therefore, both the high-stage compression mechanism 11b and the low-stage compression mechanism 11a function as blowers. Therefore, by operating the two-stage compressor 11, the heat stored in the high-pressure side circuit portion, the gas refrigerant in the intermediate pressure portion, the components such as the electric motor 11c, and the like are compressed by the two compression mechanism portions 11a, 1a that function as blowers.
The hot gas supplied from 1b is sent to the outdoor heat exchanger 14 and discharged all at once. As a result, the frost attached to the outdoor heat exchanger 14 is melted at once, and the defrosting is completed within a short time.

Next, the operation control by the control device 3 will be concretely described with reference to the flow charts shown in FIGS. When the hot water supply operation switch is turned on and the hot water supply operation is started, the outdoor blower 14a is operated (step S
1). Further, the operating frequency of the two-stage compressor 11 and the opening degree of the electric expansion valve 13 are respectively set to initial setting values (step S2), and the two-stage compressor 11 is operated (step S3).
Next, the outside temperature is detected by the outside temperature detector 32,
The evaporator temperature is detected by the evaporator temperature detector 31 (step S4), and it is determined whether the evaporator temperature has dropped to the defrosting start temperature (step S5). After confirming that the defrosting start temperature has not been reached, the steady hot water supply operation is performed (step S
6). The details of this steady hot water supply operation will be described later.

When the steady hot water supply operation is continued, when the outside air temperature is low, frost is generated in the outdoor heat exchanger 14 and the evaporator temperature is lowered. The frost amount and the evaporator temperature have a certain correlation. Therefore, when the evaporator temperature drops to the defrosting start temperature set in advance based on the experimental data, it is determined that the frost amount has reached the predetermined amount,
It is determined to be YES in step S5, and the operation shifts to defrost operation (step S7). After the defrosting operation is completed, the temporary hot water supply operation (step S8) is performed, and then the step S4.
Then, the steady hot water supply operation is restarted. The details of the defrost operation and the provisional hot water supply operation will be described later. Note that the defrosting start temperature is corrected by the outside air temperature because the frost amount of the outdoor heat exchanger 14 slightly changes if the outside air temperature is different even if the defrosting start temperature is the same. For example, when the outside air temperature is 0 ° C, the outside air temperature is -14 ° C and the outside air temperature is 10 ° C.
At ℃, it is set as -7 ℃.

Next, the details of the steady hot water supply operation will be described with reference to FIG. When the steady hot water supply operation is started by the above-described control, the operating frequency of the two-stage compressor 11 is determined according to a predetermined standard based on the outside air temperature detected in step S4 (step S11). This reference is, for example, as shown in FIG. 7, and the operating frequency of the two-stage compressor 11 is automatically selected based on the target heating temperature selected in advance and the outside air temperature detected in step S4. Stipulated in. As described above, since the two-stage compressor 11 is an inverter-driven compressor, it is possible to finely control the capacity with respect to the change in the outside air temperature and the target heating temperature.

Next, from the viewpoint of protecting the electric motor of the two-stage compressor 11, the target discharge gas temperature is set according to a predetermined standard (step S12). This standard is, for example, as shown in FIG. That is, the target discharge gas temperature is automatically selected based on the outside air temperature detected in step S4 and the target heating temperature selected in advance.

Also, a 30-minute timer for causing the detection of the outside air temperature in step S4 to be performed at a constant time interval is started (step S13). Further, the discharge gas temperature from the high-stage compression mechanism section 11b is measured by the discharge gas temperature detector 34 (step S14). The measured discharge gas temperature is compared with the target discharge gas temperature set in step S12, and the opening degree of the electric expansion valve 13 is adjusted based on this temperature difference (step S15). Then, it is determined whether the target discharge gas temperature has been reached (step S16). When the discharge gas temperature has not reached the target discharge gas temperature, steps S14 and S15 are repeated. If the discharge gas temperature has reached the target discharge gas temperature, the above 3
The process waits until the 0-minute timer times out (step S17), and ends. Therefore, the outside air temperature is detected every 30 minutes. The determination in step S5, that is, whether to perform the steady hot water supply operation or the defrost operation is also performed every 30 minutes.

The defrosting start temperature, which is the criterion for the determination in step S5, is based on the value corrected by the outside air temperature detected every 30 minutes. As described above, when the outside air temperature changes, the evaporation temperature of the outdoor heat exchanger 14 changes, so even if the evaporator temperature is the same, the frost amount varies depending on the outside air temperature. By making a determination based on the corrected defrosting start temperature, the frost is accurately detected.

Further, the two-stage compressor 1 during steady operation
Since the review setting of the operating frequency of No. 1 and the opening degree setting of the electric expansion valve 13 are also performed every 30 minutes, the outside air temperature may fluctuate up and down in a short time during the steady hot water supply operation. However, since such a vertical movement change in a short time is not detected, the capacity control of the two-stage compressor 11 and the opening control of the electric expansion valve 13 can be stably performed.

Next, details of the defrost operation are shown in FIG.
Follow the explanation below. When the defrosting operation starts under the above-described control, first, a 12-minute timer for forcibly ending the defrosting operation when the defrosting operation is continued for a certain time is started (step S21). Next, the outdoor blower 14a is stopped (step S22), and the electromagnetic opening / closing valves 16a and 17a of the defrost circuit are opened (step S23).
The two-stage compressor 11 continues to operate as it is,
The operating frequency is changed to the frequency for defrost operation (step S24). The discharge gas amount discharged from the two-stage compressor 11 is not particularly limited, and may be, for example, the discharge gas amount immediately before the defrost operation, but the larger the discharge gas amount, the more heat on the high pressure side. Since it can be sent to the outdoor heat exchanger 14 in a short time, it is preferable that the frequency for the defrost operation of the two-stage compressor 11 is large. Therefore, here, the defrost operation frequency of the two-stage compressor 11 is set to an appropriate value that is at least higher than the operation frequency during the steady hot water supply operation immediately before the defrost operation.

In this way, the discharged gas is the outdoor heat exchanger 1.
By being sent to No. 4, the defrosting of the outdoor heat exchanger progresses and the evaporator temperature rises. Further, the evaporator temperature and the degree of progress of defrost have a certain correlation. Therefore, the evaporator temperature is measured (step S25), and it is determined whether the evaporator temperature has reached the defrosting end temperature (step S26). The defrosting end temperature is obtained by obtaining experimental data indicating the relationship between the evaporator temperature and the degree of progress of defrost, and presetting the evaporator temperature indicating defrost completion based on this data.

When the evaporator temperature has reached the defrosting end temperature, it is judged that the defrosting is completed, and the electromagnetic opening / closing valves 16a and 17a of the defrosting circuit are closed to end the defrosting operation (step S28). In addition, when the evaporator temperature has not reached the defrosting end temperature and the 12-minute timer times out, it is determined that the evaporation temperature detection by the evaporator temperature detector 31 is abnormal, and it is forced. The electromagnetic on-off valves 16a and 17a of the defrost circuit are closed to end the defrost operation (steps S27 and 28).

Next, the temporary hot water supply operation will be described. This provisional hot water supply operation is a hot water supply operation that is performed after the defrost operation is completed and before switching to the steady hot water supply operation. This will be described in more detail. If the steady hot water supply operation described above is started at the same time as the defrost operation ends, the surface temperature (evaporator temperature) of the outdoor heat exchanger 14 becomes high when the outside air temperature is low, and the outside air temperature detected by the outside air temperature detector 32 becomes The temperature may be higher than the actual outside air temperature, resulting in false detection. Therefore, the provisional hot water supply operation is for avoiding the control due to such erroneous detection, and the outdoor blower 14a is operated for a predetermined time after the end of the defrost operation, and the operating frequency of the two-stage compressor 11 and the electric A hot water supply operation is performed in which the opening degree of the expansion valve 13 is constant. It should be noted that after waiting for a state where there is no risk of erroneous detection of the outside air temperature, a transition is made to a steady hot water supply operation in which the operating frequency control (capacity control) of the two-stage compressor 11 and the opening degree control of the electric expansion valve 13 are performed.

When the above-mentioned defrosting operation is completed and the provisional defrosting operation is started, a three-minute timer that determines the time of this provisional hot water supply operation is started (step S31). Next, the operating frequency of the two-stage compressor 11 is changed to the operating frequency immediately before the start of the defrost operation (step S3).
2) The opening degree of the electric expansion valve 13 is changed to the opening degree immediately before the start of the defrost operation (step S33), and the outdoor blower is operated (step S34). Then, it is controlled to return to the steady hot water supply operation when the 3-minute timer times out (step S35).

As described above, during the temporary hot water supply operation for 3 minutes, the outside air temperature detector 32 that has been heated by the defrost operation returns to normal, and the outside air temperature can be accurately detected. Further, since the defrosting operation time is performed in a short time, in the above example, the normal hot water supply operation is restored in a maximum of 15 minutes after the start of the defrosting operation. As described above, since the steady hot water supply operation is restored in a short time, it can be said that the change in the outside air temperature before and after the defrost operation is not large. Therefore, in this provisional hot water supply operation, the operating frequency of the two-stage compressor 11 is changed to the operating frequency immediately before the start of the defrost operation, and the opening degree of the electric expansion valve 13 is changed to the operating frequency immediately before the start of the defrost operation. If so, the transition to the next steady hot water supply operation will be performed smoothly.

Further, when the provisional hot water supply operation is completed in step S35, the process returns to step S4, the outside air temperature and the evaporator temperature are detected, and it is confirmed that the evaporator temperature has not fallen to the defrosting start temperature. Return to driving. Therefore, at this point, the operating frequency of the two-stage compressor 11 corresponding to the outside air temperature is determined (step S12), the opening degree of the electric expansion valve 13 is set (step S15), and
The 30-minute timer will start again, so
A stable steady hot water supply operation can be promptly performed after the provisional operation is completed.

Modifications. The above embodiment can be modified as follows. (1) Although the compressor is the two-stage compressor 11 for the supercritical refrigeration cycle in the above embodiment, it may be a single-stage compressor for a normal refrigeration cycle. In this case, the refrigerant is a natural refrigerant. Instead, other CFC gas or the like may be used. (2) The defrost circuit was provided with the bypass circuits 16 and 17 for bypassing the compressor discharge gas to the inlet side of the outdoor heat exchanger 14 in the above-mentioned embodiment. Instead of providing the refrigerant circuit, a refrigerant circuit that performs a simple refrigerating operation may be used, and the electric expansion valve may be fully opened during the defrosting operation to send hot gas to the inlet side of the outdoor heat exchanger 14.

(3) In the above embodiment, the operating frequency of the two-stage compressor 11 and the opening degree of the electric expansion valve 13 during the temporary hot water supply operation are the same as those during the steady hot water supply operation immediately before the start of the defrost operation. However, the present invention is not limited to this, and a predetermined operating frequency and valve opening may be set in advance. (4) The 30-minute timer for determining a fixed time interval for detecting the outside air temperature in the steady hot-water supply operation, the 12-minute timer as a forced termination means in the defrost operation, and the 3-minute timer for setting the time of the provisional hot-water supply operation are respectively set to this time. The present invention is not limited to the above, and can be appropriately changed.

[0057]

Since the present invention is constructed as described above, it has the following effects. According to the invention of claim 1, after the defrosting operation is completed, the evaporator temperature detector is affected by the temperature of the outdoor heat exchanger immediately after the defrosting operation is completed while the temporary operation of rotating the outdoor blower is being performed. Is excluded, and it becomes possible to detect a substantially accurate outside temperature. As a result, it becomes possible to restart the steady hot water storage operation promptly after the provisional operation is completed without erroneously detecting the outside air temperature.

Further, according to the second aspect of the present invention, the control of the compression functional force that matches the hot water supply operation condition can be finely performed, and the hot water supply operation can be performed efficiently.
Further, according to the invention described in claim 3, even if the outside air temperature fluctuates up and down in a short time during the steady hot water supply operation, such a vertical movement change in a short time is not detected. Therefore, the capacity control of the compressor and the opening degree control of the electric expansion valve can be stably performed.

According to the invention described in claim 4, the frost can be detected more accurately.
According to the invention of claim 5, after the provisional operation is completed,
It is possible to promptly perform a stable steady hot water supply operation without the outside air temperature being detected again after a short time.

According to the sixth aspect of the invention, since no large difference is expected in the outside air temperature before and after the defrosting operation, the temporary hot water supply operation is performed with the compression function force and the electric expansion valve of the next steady hot water supply operation. Since the operation is performed under substantially the same conditions as the opening degree, the transition to the steady hot water supply operation is smoothly performed. Further, according to the invention described in claim 7, during the defrost operation, the heat on the high pressure side of the compressor is sent to the evaporator at once, so that the time of the defrost operation can be shortened and the steady hot water supply operation is promptly restored. be able to.

According to the eighth aspect of the invention, even if the evaporator temperature detector malfunctions for some reason, the return to the steady hot water supply operation is guaranteed. According to the invention described in claim 9, the compulsory means can be configured by a simple timer.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a heat pump water heater according to an embodiment of the present invention.

FIG. 2 is a Mollier diagram illustrating a refrigeration cycle during a steady hot water supply operation of the heat pump hot water supply device.

FIG. 3 is a control flowchart of hot water supply operation by the control device of the heat pump hot water supply device.

FIG. 4 is a detailed flowchart of a steady hot water supply operation in the control flowchart.

FIG. 5 is a detailed flowchart of a defrost operation in the control flowchart.

FIG. 6 is a detailed flowchart of a provisional hot water supply operation in the control flowchart.

FIG. 7 is a diagram showing an example of setting the operating frequency of the compressor with respect to the outside air temperature and the target heating temperature in the heat pump water heater according to the embodiment of the present invention.

FIG. 8 is a diagram showing an example of setting a target heating temperature for an outside air temperature and a target discharge gas temperature in the heat pump hot water supply apparatus according to the embodiment of the present invention.

[Explanation of symbols]

1 Refrigerator 2 Hot water supply unit 3 control device 11 (Inverter drive type) 2-stage compressor 11a Low-stage compression mechanism section 11b High-stage compression mechanism section 12 High-pressure side heat exchanger 13 Electric expansion valve 14 outdoor heat exchanger 14a outdoor blower 15 Accumulator 16 Bypass circuit 16a solenoid valve 17 Bypass circuit 17a Solenoid on-off valve 18 Discharge pipe 19 Piping (on the inlet side of the outdoor heat exchanger) 31 Evaporator temperature detector 32 Outside temperature detector 34 Discharge gas temperature detector

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoshi Hoshino             1 Otsuki-cho, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning             Within the corporation (72) Inventor Kiyoshi Koyama             1 Otsuki-cho, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning             Within the corporation (72) Inventor Sadahiro Takizawa             1 Otsuki-cho, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning             Within the corporation (72) Inventor Chiaki Shichiji             1 Otsuki-cho, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning             Within the corporation (72) Inventor Shigaya Ishigaki             1 Otsuki-cho, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning             Within the corporation

Claims (9)

[Claims] 1. A compressor, a high-pressure side heat exchanger that heats hot water with discharge gas from the compressor, an electric expansion valve, and an outdoor heat exchange that acts as an evaporator by exchanging heat with the outside air blown by an outdoor blower. A main circuit with sequentially connected heat exchangers, and a refrigerant circuit having at least a defrost circuit for circulating hot gas to the outdoor heat exchanger; an evaporator temperature detector for detecting the surface temperature of the outdoor heat exchanger as the evaporator temperature; The outdoor air temperature detector installed near the outdoor heat exchanger to detect the temperature of the outdoor air taken into the outdoor heat exchanger, and the evaporator temperature detected by the evaporator temperature detector is the defrost of the outdoor heat exchanger. Until the defrosting start temperature set in advance as the start value falls, the compressor capacity control and the electric expansion valve opening control are performed according to a predetermined standard corresponding to the outside air temperature detected by the outside air temperature detector. When the evaporator temperature detected by the evaporator temperature detector drops to the defrosting start temperature, the outdoor blower is stopped and the defrost circuit is opened to operate the compressor. Defrost operation is performed, and during this defrost operation, when the evaporator temperature detected by the evaporator temperature detector rises to the defrost end temperature preset as the defrost completion value of the outdoor heat exchanger, the defrost circuit is activated. While closing and stopping the defrost operation, restarting the operation of the outdoor blower, and further performing a temporary hot water supply operation in which the compressor is operated with the capacity of the compressor and the opening degree of the electric expansion valve being set to predetermined values, and after a lapse of a predetermined time. A heat pump hot water supply apparatus comprising: an operation control device that restarts the steady hot water supply operation. 2. The compressor is driven by an inverter,
The heat pump hot water supply apparatus according to claim 1, wherein the compression functional force is controlled by changing the operating frequency by the inverter. 3. The heat pump type hot water supply apparatus according to claim 1, wherein the operation control device detects the outside air temperature by the outside air temperature detector each time a steady hot water supply operation elapses for a certain period of time. 4. The heat pump hot water supply apparatus according to claim 3, wherein the operation control device corrects the defrosting start temperature based on the outside air temperature measured at regular intervals. 5. The operation control device detects the outside air temperature when restarting the steady hot water supply operation after the provisional operation ends,
The heat pump hot water supply system according to claim 3, wherein the capacity of the compressor and the opening degree of the electric expansion valve are set in accordance with the outside air temperature according to the predetermined standard, and the timekeeping for detecting the outside air temperature is started at regular intervals. apparatus. 6. The operation control device sets the capacity of the compressor and the opening degree of the electric expansion valve during the provisional operation to the state during the steady hot water supply operation immediately before the defrost operation.
The heat pump hot water supply apparatus according to any one of items 1 to 5. 7. The heat pump hot water supply apparatus according to claim 1, wherein the operation control device operates the compressor at the time of defrosting operation with a capacity equal to or higher than the capacity at the time of steady hot water supply operation immediately before defrosting operation. . 8. The operation control device, when the defrost operation, the temperature detected by the evaporator temperature detector,
3. The method according to claim 1, further comprising a compulsory unit for forcibly ending the defrosting operation when the defrosting end temperature is not reached within a certain time.
The heat pump hot water supply apparatus according to any one of items 1 to 7. 9. The heat pump hot water supply apparatus according to claim 8, wherein in the operation control device, the forcing means is constituted by a timer.