JP6097930B2 - Heat pump water heater - Google Patents

Description

  The present invention relates to a heat pump water heater.

  Conventionally, this type of heat pump water heater is, for example, as shown in FIG. 13 (see, for example, Patent Document 1).

  FIG. 13 shows a conventional heat pump water heater described in Patent Document 1. As shown in FIG.

  As shown in FIG. 13, a compressor 104, a water-refrigerant heat exchanger 105, a decompression means 106, and an air heat exchanger (evaporator) 107 are connected in a tubular shape with a refrigerant pipe to form a heat pump cycle.

  The bottom of the hot water storage tank 103, the pump 119, and the water / refrigerant heat exchanger 105 are sequentially connected by an HP pipe 118. Further, the outlet hot water temperature of the water-refrigerant heat exchanger 105 (hereinafter referred to as hot water temperature) is detected by a hot water temperature sensor 121 installed in the middle of the HP pipe 118.

  In the hot water storage operation mode, water at the bottom of the hot water storage tank 103 is transferred to the water / refrigerant heat exchanger 105 by the pump 119, where it is heated to become hot water by heat exchange with the refrigerant in the heat pump cycle, and the HP pipe 118, hot water supply It returns to the upper part of the hot water storage tank 103 via the pipe 120.

  At this time, the hot water temperature, the rotation speed of the pump 119, and the operation control of each component of the heat pump cycle are performed by the control device 125.

  A hot water discharge pipe 120 is connected to the top of the hot water storage tank 103, and a water supply pipe 109 is connected to the bottom of the hot water storage tank 103.

  The hot water mixing valve 111 mixes the hot water in the upper part of the hot water storage tank supplied from the hot water supply pipe 120 and the water supplied from the water supply pipe 109 to supply hot water at a predetermined temperature from the hot water supply terminal 114 via the hot water supply pipe 113. Let The hot water temperature at the outlet of the hot water supply mixing valve 111 is detected by a hot water supply temperature sensor 122 installed in the middle of the hot water supply pipe 113.

  The hot water mixing valve 112 mixes the hot water in the upper part of the hot water storage tank supplied from the hot water pipe 120 and the water supplied from the water supply pipe 109 to supply hot water at a predetermined temperature to the hot water pipe 115 and the hot water on / off valve 116. Hot water is supplied to the bathtub 117 via

  The hot water temperature at the outlet of the hot water mixing valve 112 is detected by a hot water temperature sensor 123 installed in the middle of the hot water pipe 115. Further, the water level of the bathtub 117 is detected by a hot water pressure sensor 129 installed in the hot water pipe 115.

  In addition, the hot water operation to the bathtub 117 has a hot water operation mode, and at the start of the hot water operation mode, the heat pump cycle is started, the hot water on / off valve 116 is opened, and the HP pipe 118 is connected. The hot water passed through and the hot water from the hot water storage tank 103 join together in the hot water discharge pipe 120, and are supplied to the bathtub 117 through the hot water mixing valve 112 and the hot water pipe 115.

  In addition, the coefficient of performance of the heat pump cycle (hereinafter referred to as COP) is reduced by reducing the temperature of the hot water in the hot water operation mode to the temperature of the hot water in the hot water operation mode and lowering the heating capacity. Since the COP is improved over time, an efficient hot water operation can be performed.

JP 2011-21828 A

  However, in the conventional configuration, in the hot water operation mode, hot water having a low temperature that has passed through the HP pipe 118 and hot water from the hot water storage tank 103 are merged in the hot water discharge pipe 120, but the flow rate is not increased in the merge portion. A device for adjusting the flow rate is not installed, and the flow rate ratio becomes a result.

  Therefore, when the flow rate of hot water having a low temperature passing through the HP pipe 118 is large, or when the hot water from the hot water storage tank 103 is lower than normal, the target hot water temperature is not reached and the bathtub 117 has a temperature higher than the set temperature. Low hot water would be filled, and there was a problem of impairing user comfort.

  This invention solves the said conventional subject, and it aims at providing the heat pump water heater excellent in energy saving property, without impairing a user's comfort.

In order to solve the conventional problems, a heat pump water heater of the present invention stores a heat pump cycle in which a compressor, a water refrigerant heat exchanger, a decompression unit, and an evaporator are connected, and hot water heated in the heat pump cycle. A hot water storage operation comprising a hot water storage tank, a hot water temperature detection means disposed in the water refrigerant heat exchanger, a hot water storage temperature detection means, and a control means, and stores hot water heated by the heat pump cycle in the hot water storage tank. mode and, while generating heat at least the hot water storage the low temperature hot water than the hot water temperature in the operation mode the heat pump cycle includes a hot beam operation mode for pouring the bath, and the melt-beam operation mode is the hot water heated by the heat pump cycle, once the hot water storage to flow into the tank after mixing with the hot water of the hot water storage tank, the bath side If the detected temperature of the hot water storage temperature detection means is a predetermined value or less, pouring into the bathtub is started in the hot water operation mode, while the detection of the hot water storage temperature detection means When the temperature is higher than a predetermined value, the compressor is not operated, and the hot water stored in the hot water storage tank is used to start pouring water into the bathtub .

  As a result, in the hot water operation mode, the hot water heated in the heat pump cycle once enters the hot water storage tank, is mixed with the hot water in the hot water storage tank, and is supplied to the bathtub. The heat pump water heater excellent in energy saving can be provided without being stretched on the bathtub and without impairing the comfort of the user.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to fill hot water of the temperature always set, and the heat pump water heater excellent in energy saving property can be provided, without impairing a user's comfort.

Configuration diagram of a water heater in Embodiment 1 of the present invention Figure showing changes in temperature distribution in the hot water storage tank Control flow chart at the start of the hot water beam The figure which shows the sequence of the operation operation of the hot water beam operation mode The figure which shows the relationship between COP and tapping temperature of the same heat pump cycle The figure which shows the relationship between the heating capacity and compression ratio of the heat pump cycle in the hot water beam operation mode The figure which shows the relationship between the heating capability of a heat pump cycle at the time of the hot water beam operation mode, and COP of a heat pump cycle The figure which shows the relationship between the heating capability of the heat pump cycle at the time of the hot water beam operation mode, and bath pouring COP The figure which shows the relationship between compressor rotation speed and bath pouring COP at the time of the hot water beam operation mode Control flow chart when the hot water beam operation mode is stopped (A) The figure which showed the change of the temperature distribution in a hot water storage tank when there is the same middle temperature hot water supply circuit (b) The figure which showed the change of the temperature distribution in the hot water storage tank when there is no same temperature hot water supply circuit The block diagram of the heat pump water heater in Embodiment 2 of this invention Configuration diagram of conventional heat pump water heater

A first aspect of the invention is arranged in a heat pump cycle in which a compressor, a water refrigerant heat exchanger, a decompression unit, and an evaporator are connected, a hot water storage tank for storing hot water heated in the heat pump cycle, and the water refrigerant heat exchanger. A hot water storage temperature detection means , a hot water storage temperature detection means, and a control means, a hot water storage operation mode for storing hot water heated in the heat pump cycle in the hot water storage tank, and at least a hot water temperature in the hot water storage operation mode while heating generates an even lower temperature hot water in said heat pump cycle includes a hot beam operation mode for pouring the bath, and the melt-beam operation mode is the hot water heated by the heat pump cycle, once the allowed to flow into the hot water storage tank, said after mixed with hot water in the hot water storage tank, a driving mode for supplying to the tub side, the hot-water storage temperature detecting means When the detected temperature is less than or equal to a predetermined value, pouring into the bathtub is started in the hot water operation mode. On the other hand, when the detected temperature of the hot water storage temperature detecting means is higher than a predetermined value, the compressor Is a heat pump water heater that starts pouring into the bathtub using hot water stored in the hot water storage tank without operating .

  Thereby, in the hot water operation mode, the hot water heated in the heat pump cycle once enters the hot water storage tank, is mixed with the hot water in the hot water storage tank, and is supplied to the bathtub. The heat pump water heater excellent in energy saving can be provided without being stretched on the bathtub and without impairing the comfort of the user.

  2nd invention was connected between the hot water return piping which flows the hot water heated in the said heat pump cycle into the said hot water storage tank, and the upper part and the lower part of the said hot water storage tank in the said hot water operation mode The hot water return pipe is connected to the upper side of the hot water storage tank from the intermediate temperature hot water pipe.

  As a result, in hot water operation mode, hot water heated in the heat pump cycle once enters the hot water storage tank, so that the temperature stratification of hot water in the hot water storage tank, which has become slightly worse, is improved by the medium temperature hot water. Thus, a heat pump water heater excellent in energy saving can be provided without lowering the operating efficiency of the night boiling operation performed at the same time.

  According to a third aspect of the present invention, in the hot water operation mode, the heating capacity of the heat pump cycle is equal to or greater than the heating capacity in the hot water storage operation mode.

  Thereby, in the hot water operation mode, a minimum compression ratio can be ensured, the reliability of the compressor can be improved, and a heat pump water heater excellent in energy saving can be provided.

  According to a fourth aspect of the present invention, in the hot water operation mode, the rotational speed of the compressor is equal to or higher than the rotational speed of the compressor in the hot water storage operation mode.

  Thereby, in the hot water operation mode, a minimum compression ratio can be ensured, the reliability of the compressor can be improved, and a heat pump water heater excellent in energy saving can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a heat pump water heater in the first embodiment of the present invention. The heat pump water heater is composed of a heat pump unit 2a and a hot water storage unit 2b.

  The heat pump unit 2a is provided with a heat pump cycle 1 in which a compressor 4, a water-refrigerant heat exchanger 5, a decompression means 6 such as an expansion valve, and an evaporator 7 which is an air heat exchanger are connected in an annular shape with a refrigerant pipe. A refrigerant is sealed inside the refrigerant pipe. A fan 8 supplies air to the evaporator 7.

  The hot water storage unit 2b is provided with a boiling circuit by connecting the bottom of the hot water storage tank 3, the boiling forward pipe 32, the water refrigerant heat exchanger 5, the boiling return pipe 33, the four-way switching valve 18a, and the hot water storage tank 3 in an annular shape. It has been.

  A boiling pump 21 that conveys the water at the bottom of the hot water storage tank 3 to the water-refrigerant heat exchanger 5 is connected to the middle of the boiling piping 32.

  A boiling return pipe 33 is connected to the inlet side of the four-way switching valve 18a. The outlet side of the four-way switching valve 18a is connected to the bottom of the hot water storage tank 3 by a boiling bypass pipe 34, and the other outlet side of the four-way switching valve 18a is connected to the hot water storage tank via the heating pipe 35 and the first hot water discharge pipe 9. The other outlet side of the four-way switching valve 18a is connected to the upper part of the hot water storage tank 3 via a hot water return pipe 36.

  That is, the hot water in the boiling return pipe 33 conveyed by the boiling pump 21 is returned to the bottom of the hot water storage tank 3 by the four-way switching valve 18a, and the upper part of the hot water storage tank 3 (the first outlet pipe 9 or hot water). It is possible to switch between returning to the return pipe 36).

  Further, a tapping temperature detecting means 42 that is a tapping temperature sensor that detects the water temperature at the outlet of the water-refrigerant heat exchanger 5 is provided.

  A plurality of remaining hot water thermistors (temperature sensors) 40a to 40e as hot water storage temperature detecting means are installed on the wall surface of the hot water storage tank 3, and the amount of heat stored in the hot water storage tank 3 is grasped based on the temperature of the remaining hot water thermistors 40a to 40e. can do.

Water from the water supply passes through the water supply pipe 11 to which the pressure reducing valve 20 is connected midway, and the hot water storage tank 3
Or a third mixing valve 14 and a first mixing valve 15 which will be described later. The water supply pipe 11 branches into a second water supply branch pipe 12 a, a third water supply branch pipe 12 b, and a first water supply branch pipe 12 c at the water supply branch section 12, and the second water supply branch pipe 12 a is formed at the bottom of the hot water storage tank 3. The third water supply branch pipe 12 b is connected to the third mixing valve 14, and the first water supply branch pipe 12 c is connected to the first mixing valve 15.

  A first hot water discharge pipe 9 is connected to the upper part of the hot water storage tank 3, and an intermediate temperature hot water supply pipe 10 is connected between the position where the first hot water discharge pipe 9 is connected in the vertical direction of the hot water storage tank 3 and the bottom of the hot water storage tank 3. ing. The other end of the first hot water discharge pipe 9 is branched into a hot water branch pipe 16 and a follower pipe 25, the hot water branch pipe 16 is connected to the second mixing valve 13, and the follower pipe 25 is connected to the bath heat exchanger 24. Has been.

  The hot water supply circuit mixes the hot water in the hot water storage tank 3 and the water supplied from the water supply with the second mixing valve 13, the third mixing valve 14, and the first mixing valve 15 to obtain hot water at a predetermined temperature. It is a circuit for supplying hot water to a hot water supply terminal (not shown) such as a shower or a bathtub.

  The second mixing valve 13 mixes the hot water supplied from the first hot water discharge pipe 9 and the hot water supplied from the intermediate hot water hot water pipe 10 and causes the hot water to flow out from the hot water joining pipe 17. The outgoing hot water junction pipe 17 branches into a first outgoing hot water joint pipe branch pipe 17a and a second outgoing hot water joint pipe branch pipe 17b. The first outgoing hot water joint pipe branch pipe 17a is connected to the third mixing valve 14 and the second outgoing hot water joint pipe. The branch pipes 17b are connected to the first mixing valve 15, respectively.

  The third mixing valve 14 mixes hot water supplied from the first outlet hot water merging pipe branch pipe 17a and water supplied from the third water supply branch pipe 12b, and causes the hot water to flow out from the hot water pipe 28 to supply hot water such as a currant or shower. Hot water of a predetermined temperature is supplied from a terminal (not shown).

  The hot water supply pipe 28 connected to the outlet side of the third mixing valve 14 is provided with a hot water supply temperature sensor 43a as a first hot water supply temperature detection means. When hot water is supplied from a hot water supply terminal, the hot water supply temperature sensor 43a detects the hot water supply temperature sensor 43a. The control unit 51 controls the mixing ratio of the third mixing valve 14 so that the temperature becomes the target set temperature (set by the user from the remote controller 50).

  The first mixing valve 15 mixes the hot water supplied from the second outlet hot water junction branch pipe 17b and the water supplied from the first water supply branch pipe 12c and causes the hot water to flow out from the bath pouring pipe 27. Then, hot water having a predetermined temperature is poured into the bathtub 31 through the bath going-out pipe 29 and the bath return pipe 30.

  The bath pouring pipe 27 connected to the outlet side of the first mixing valve 15 is provided with a bath hot water temperature sensor 43b as a second hot water temperature detecting means. The control unit 51 controls the mixing ratio of the third mixing valve 14 so that the detected temperature of the sensor 43b becomes the target set temperature (set by the user from the remote controller 50).

  The bath chasing circuit can heat the hot water in the bathtub 31 to a predetermined temperature by exchanging heat between the hot water in the hot water storage tank 3 and the hot water in the bathtub 31 by the bath heat exchanger 24.

  The bath chasing circuit connects the hot water storage tank 3, the first hot water discharge pipe 9, the chasing pipe 25, the bath heat exchanger 24, the chasing pump 22, the chasing return pipe 26, and the hot water tank 3 in a ring shape, and a bathtub 31 The bath return pipe 30, the bath circulation pump 23, the bath heat exchanger 24, the bath return pipe 29, and the bathtub 31 are connected in a ring shape. A bath temperature sensor 45 as a bathtub temperature detecting means for detecting temperature and a water level sensor 46 as a bathtub water level detecting means are installed.

Moreover, the heat pump water heater of the present invention is heated (heated up) in the heat pump cycle 1.
When the hot water storage operation mode in which the hot water is stored in the hot water storage tank 3 and the bath automatic hot water operation in which hot water of a predetermined temperature is applied to the bathtub 31 by a predetermined amount are started, the heat pump cycle 1 is started and the pouring valve 19 is started. And after mixing the hot water supplied from the water refrigerant heat exchanger 5 and the hot water supplied from the first hot water discharge pipe 9, the second mixing valve 13, the first mixing valve 15, and the bath pouring pipe 27 are passed through. And a hot water operation mode for pouring into the bathtub 31.

  In the hot water operation mode, the operation can be started by operating the remote controller 50 as a setting operation means (for example, pressing a bath automatic hot water button).

  Operation control of each device in the hot water storage operation mode and the hot water operation mode is performed by the control means.

  About the heat pump water heater comprised as mentioned above, operation | movement of the operation mode of a heat pump water heater is demonstrated.

  The hot water storage operation mode is a mode in which the water at the bottom of the hot water storage tank 3 is heated by the heat pump cycle 1 and then stored in the upper part of the hot water storage tank 3. It is normal to use cheap electricity at midnight (23:00 to 7:00 the next morning), but if the amount of hot water in the hot water storage tank 3 decreases and the risk of running out of hot water arises, the daytime There is a case of driving from (7 o'clock to 23 o'clock).

  During the hot water storage operation, the refrigerant sealed in the heat pump cycle 1 of the heat pump unit 2a is sucked into the compressor 4 in a low-pressure gas state, compressed into a high-temperature and high-pressure state, and then transferred to the water-refrigerant heat exchanger 5. It exchanges heat with the water transported from the hot water storage tank 3 and becomes itself in a low temperature and high pressure state.

  Thereafter, the refrigerant becomes a gas-liquid two-phase refrigerant expanded to a low-temperature and low-pressure state by the decompression means 6 such as an expansion valve, and the evaporator 7 absorbs heat from the outside air blown by the fan 8 to become a low-pressure gas refrigerant. Repeatedly inhaling.

  On the other hand, the water at the bottom of the hot water storage tank 3 is conveyed to the water / refrigerant heat exchanger 5 via the boiling forward pipe 32 by the boiling pump 21, and is heated by exchanging heat with the refrigerant of the heat pump cycle 1. It becomes warm water. Thereafter, the heated hot water is returned to the top or bottom of the hot water storage tank 3 through the boiling return pipe 33 and the four-way switching valve 18a.

  The temperature of the hot water at the outlet of the water-refrigerant heat exchanger 5 does not reach the target hot water temperature immediately after the heat pump cycle 1 is started, but takes some time. While the temperature detected by the hot water temperature detection means 42 (hereinafter referred to as the detected temperature) is lower than the target hot water temperature (for example, when the temperature difference between the target hot water temperature and the detected temperature is greater than or equal to a predetermined value), boiling is performed. The hot water in the return pipe 33 is returned to the bottom of the hot water storage tank 3 through the boiling bypass pipe 34 by the four-way switching valve 18a.

  Thereafter, when the detected temperature approaches the target hot water temperature (for example, when the temperature difference between the target hot water temperature and the detected temperature becomes less than a predetermined value), the four-way switching valve 18a is switched to warm water in the boiling return pipe 33. Is returned to the upper part of the hot water storage tank 3 through the boiling pipe 35 and the first hot water discharge pipe 9. With the above operation, the hot temperature heated in the heat pump cycle 1 is stored in the hot water storage tank 3.

  Next, the operation of the medium temperature hot water by the second mixing valve 13 in the hot water supply circuit will be described. FIG. 2 shows an example of the temperature distribution in the hot water storage tank 3 after supplying a predetermined amount of hot water from a state where the entire amount of the hot water storage tank 3 is boiled. The solid line in FIG. 2 indicates the case where the medium temperature hot water is performed, and the broken line indicates the case where the medium temperature hot water is not performed.

  When hot water is supplied to the hot water supply terminal or the bathtub 31 at the target hot water supply temperature T1 (° C.) set by the user, hot water supplied from the upper part of the hot water storage tank 3 via the first hot water discharge pipe 9 and the hot water branch pipe 16; Hot water supplied from a substantially central portion of the hot water storage tank 3 via the intermediate hot water discharge pipe 10 is mixed by the second mixing valve 13, and hot water having a temperature higher than the target hot water supply temperature T1 by a predetermined temperature difference δT (K). As shown in FIG.

  When hot water is supplied to the hot water supply terminal at the target hot water supply temperature T1 (° C.), hot water of T1 + δT (° C.) supplied from the second mixing valve 13 via the hot water joining pipe 17 and the first hot water joining pipe branch pipe 17a; The third mixing valve is mixed with the water supplied from the water supply pipe 11 via the second water supply branch pipe 12b by the third mixing valve 14 so that the detected temperature of the hot water supply temperature sensor 43a becomes the target hot water supply temperature T1. 14 is controlled by the control means 51.

  When hot water is supplied to the bathtub 31 at the target hot water supply temperature T1 (° C.), the hot water of T1 + δT (° C.) supplied from the second mixing valve 13 via the hot water joining pipe 17 and the second hot water joining pipe branch pipe 17b. And the water supplied from the water supply pipe 11 via the first water supply branch pipe 12c are mixed by the first mixing valve 15 so that the detected temperature of the bath hot water temperature sensor 43b becomes the target hot water temperature T1. The mixing ratio of the 1 mixing valve 15 is controlled by the control means 51.

  In the present embodiment, the hot water temperature supplied from the first hot water discharge pipe 9 and the hot water temperature supplied from the intermediate hot water hot water pipe 10 are used as the remaining hot water without installing a temperature sensor on the outlet side of the second mixing valve 13. The temperature is detected by the thermistors 40a to 40e and the outlet temperature is controlled to be T1 + δT (° C.). A second mixing valve outlet temperature sensor is added to the outlet of the second mixing valve 13, and this second mixing valve is controlled. The second mixing valve 13 may be controlled so that the temperature detected by the outlet temperature sensor becomes T1 + δT (K).

  With the above operation, the medium temperature of the boundary layer between the hot water in the upper part of the hot water storage tank 3 and the low temperature water in the bottom of the hot water storage tank 3 (hereinafter referred to as the intermediate temperature layer, the hot water existing in the intermediate temperature layer is referred to as the intermediate temperature) Since it is discharged out of the hot water storage tank 3 from the medium temperature hot water discharge pipe 10, it is possible to suppress an increase in the water temperature (ΔT) at the bottom of the hot water storage tank 3 as shown in FIG.

  As a characteristic of the heat pump cycle 1, it is known that the coefficient of performance (COP) decreases as the incoming water temperature during the boiling operation, that is, the inlet water temperature of the water-refrigerant heat exchanger 5 increases. Therefore, by suppressing the rise in the water temperature at the bottom of the hot water storage tank 3 by the medium temperature hot water, it is possible to improve the COP of the heat pump cycle 1 during the boiling operation and to save energy.

  Next, hot water operation to the bathtub 31 will be described.

  FIG. 3 shows a control flowchart at the start of hot water. In FIG. 3, when a hot water bath command is input by the user via the remote controller 50 (step 1), the temperature of the remaining hot water thermistors 40a to 40e installed on the wall surface of the hot water storage tank 3 in order to grasp the remaining hot water amount. Is detected (step 2). Next, in order to determine whether the amount of remaining hot water is large or small, it is compared whether the temperature of the remaining hot water thermistor 40d is higher or lower than a predetermined temperature (step 3).

  For example, when the temperature (T40d) of the remaining hot water thermistor 40d is 60 ° C. or less at step 3, it is determined that the amount of remaining hot water is small, the compressor 4 of the heat pump cycle 1 is operated (step 4), and the hot water from the hot water storage tank 3 is Bath hot water is started in a so-called hot water operation mode in which both hot water boiled by the heat pump is used to heat the bath (step 6).

  On the other hand, when the temperature of the remaining hot water thermistor 40d (T40d) is higher than 60 ° C. at step 3, it is determined that the amount of remaining hot water is large, and the compressor 4 of the heat pump cycle 1 does not operate (step 5). The so-called normal hot water operation mode in which the hot water bath is heated only (step 6).

  FIG. 4 shows a control sequence in the hot water operation mode. In FIG. 4, when a bath hot water command is input by the user via the remote controller 50, the remaining hot water amount is detected as shown in FIG. 3, and when it is determined that the remaining hot water amount is small, the compressor 4 is activated. Thus, the heat pump cycle 1 is started and the boiling pump 21 is operated.

  In addition, the pouring valve 19 is opened, and the four-way switching valve 18a is switched so that the boiling return pipe 33 and the hot water return pipe 36 communicate with each other.

  By this operation, the water at the bottom of the hot water storage tank 3 is conveyed to the water / refrigerant heat exchanger 5 by the boiling pump 21, where it is heated and exchanged with the refrigerant of the heat pump cycle 1, and then heated to the boiling return pipe 33. It passes through the four-way switching valve 18 a and the hot water return pipe 36 and once enters the hot water storage tank 3. Thereafter, it is mixed with hot water in the hot water storage tank 3, and the first outlet pipe 9, the second mixing valve 13, the first mixing valve 15, the bath pouring pipe 27, the pouring valve 19, the bath outlet pipe 29, and the bath return pipe 30. The hot water is poured into the bathtub 31 via

  At the beginning of the heat pump cycle 1, the outlet water temperature of the water-refrigerant heat exchanger 5 does not rise immediately, but after passing through the hot water return pipe 36, it once enters the hot water storage tank 3 and mixes with the hot water in the hot water storage tank 3. Then, since it is mixed with the hot water supplied via the first hot water discharge pipe 9, it does not fall below the target hot water supply temperature.

  FIG. 5 shows the relationship between the coefficient of performance (COP) of the heat pump cycle and the tapping temperature. Here, the coefficient of performance (COP) of the heat pump cycle in the hot water storage operation mode is represented by COPA, and the coefficient of performance (COP) of the heat pump cycle in the hot water operation mode is represented by COPB.

  The hot water temperature in the hot water storage operation mode (detected temperature of the hot water temperature detection means 42) is generally 65 ° C. to 90 ° C., but the hot water temperature in the hot water operation mode is lower than the hot water temperature in the hot water operation mode (for example, , 35 ° C.), COPB can be improved over COPA and energy can be saved.

  As a specific means for lowering the hot water temperature in the hot water operation mode to be lower than the hot water temperature in the hot water operation mode, increasing the flow rate by increasing the rotation speed of the boiling pump 21 than in the hot water operation mode. Thus, the outlet temperature of the water-refrigerant heat exchanger 5 can be made lower than the outlet temperature in the hot water storage operation mode.

  FIG. 6 shows the relationship between the heating capacity of the heat pump cycle 1 and the compression ratio in the hot water operation mode. When the rotation speed of the compressor 4 is the same, the higher the compression ratio, the higher the discharge pressure, and the higher the discharge temperature and the higher the heating capacity. However, the characteristics increase slightly to the right (solid line).

  Furthermore, when the tapping temperature is the same, the discharge pressure is almost the same regardless of the heating capacity, but the higher the heating capacity, the higher the rotation speed of the compressor 4 and the lower the suction pressure, so the compression ratio increases. It becomes the characteristic of rising to the right (dashed line).

  For example, if the compression ratio that can ensure the reliability of the compressor 4 is d (broken line), it can be seen that the lower the heating capacity, the lower the rotation speed of the compressor 4 but the higher the hot water temperature.

  FIG. 7 shows the relationship between the heating capacity of the heat pump cycle 1 in the hot water operation mode and COPB, which is the coefficient of performance (COP) of the heat pump cycle in the hot water operation mode. In the compression ratio d in FIG. 6, when the heating capacity in the hot water storage operation mode is 4.5 (kW), COPB peaks at e1 (kW) lower than the heating capacity.

  However, in the hot water operation mode, hot water from the hot water storage tank 3 and hot water from the heat pump cycle 1 are used in combination, so that if the heating capacity of the heat pump cycle 1 is low, a large amount of hot water from the hot water storage tank 3 is required. Become.

  FIG. 8 shows the relationship between the heating capacity of the heat pump cycle 1 and the bath pouring COP in the hot water operation mode. Here, the bath pouring COP is represented by (Equation 1).

  The bath pouring COP has a COPA in the hot water storage operation mode (for example, a heating capacity of 4.5 kW), an amount of heat used from the hot water storage tank 3 during hot water filling, and a COPB in the hot water operation mode (for example, a heating capacity of 3.0 kW, 3 .5 kW, 4.0 kW, 4.5 kW, 5.0 kW) and expressed by the amount of heat boiled in the heat pump cycle 1 and the amount of hot water.

  Here, the hot water heat amount is the heat amount of hot water that has entered the bathtub 31, and is represented by the sum of the heat amount used from the hot water storage tank 3 and the heat amount boiled in the heat pump cycle 1. The amount of heat boiled in the heat pump cycle 1 is calculated by the product of the heating capacity of the heat pump cycle 1 and the operation time. Therefore, the amount of heat used from the hot water storage tank 3 is calculated as the difference between the amount of heat of the hot water that has entered the bathtub 31 and the amount of heat that has been boiled in the heat pump cycle 1.

  As can be seen from FIG. 8, when the heating capacity in the hot water storage operation mode is 4.5 (kW), the bath pouring COP peaks at e2 (kW), which is larger than the heating capacity.

  FIG. 9 shows the relationship between the rotational speed of the compressor 4 and the bath pouring COP in the hot water operation mode. As in FIG. 8, for example, the compressor rotation speed is changed to 30 Hz, 35 Hz, 40 Hz, 45 Hz, and 50 Hz, and the bath pouring COP is calculated from the heating ability for each rotation speed.

  As can be seen from FIG. 9, in the hot water pouring COP, when the rotation speed of the compressor 4 in the hot water storage operation mode is 45 (Hz), for example, e3 (Hz) higher than the rotation speed reaches a peak. .

  Next, the stop time of the hot water operation mode will be described.

  FIG. 10 shows a control flowchart when the hot water operation mode is stopped. In FIG. 10, when a predetermined amount of hot water is applied by the water level sensor 46 or the like during a hot water bath operation (step 1) in the hot water operation mode, when the hot water hot water completion is detected (step 2), the remaining hot water amount is grasped. Therefore, the temperature of the remaining hot water thermistors 40a to 40e installed on the wall surface of the hot water storage tank 3 is detected (step 3).

  Next, in order to determine whether the amount of remaining hot water is large or small, it is compared whether the temperature of the remaining hot water thermistor 40b is higher or lower than a predetermined temperature (step 4). For example, in step 4, when the temperature (T40b) of the remaining hot water thermistor 40b is less than 60 ° C., it is determined that the amount of remaining hot water is small, and the hot pump operation mode is shifted to the hot water storage operation mode without stopping the operation of the heat pump. (Step 5). In the hot water storage operation mode, when a predetermined condition is satisfied, the hot water storage operation is completed (step 6), and the operation of the compressor 4 of the heat pump cycle 1 is stopped (step 7).

  On the other hand, when the temperature (T40b) of the remaining hot water thermistor 40b is 60 ° C. or more at step 4, it is determined that the amount of remaining hot water is large, and the operation of the compressor 4 of the heat pump cycle 1 is stopped (step 7).

  Therefore, when the amount of remaining hot water is small, the compressor is shifted from the hot water operation mode to the hot water storage operation mode without stopping, so that the start-up loss can be reduced as compared with the case of newly operating in the hot water storage operation mode. Further, when the amount of remaining hot water is large, the hot water operation mode is completed and the operation of the compressor is stopped, so that energy loss due to excess hot water can be reduced.

  Fig.11 (a) is the figure which showed the change of the temperature distribution in the hot water storage tank in case there exists an intermediate temperature hot-water supply circuit. 61 is the temperature distribution before performing hot water in the hot water operation mode, 62 is the temperature distribution after performing hot water in the hot water operation mode, and 63 is the temperature distribution after performing hot water supply and boiling operation thereafter. Show.

  By performing hot water heating in the hot water operation mode, the temperature of the upper part of the hot water storage tank 3 decreases (61 → 62). Thereafter, by performing hot water supply and boiling operation while performing medium temperature hot water, the angle of the temperature distribution changes from α → β (β> α) (62 → 63). This means that the temperature distribution, which was slightly worsened by hot water in hot water operation mode, could be improved by medium temperature hot water, and the reduction in operating efficiency of the subsequent night boiling operation can be avoided. The energy saving performance is not impaired.

  FIG.11 (b) is the figure which showed the change of the temperature distribution in the hot water storage tank when there is no intermediate temperature hot-water supply circuit. 61 is the temperature distribution before performing hot water in the hot water operation mode, 64 is the temperature distribution after performing hot water in the hot water operation mode, and 65 is the temperature distribution after performing hot water supply and boiling operation thereafter. Show.

  By performing hot water heating in the hot water operation mode, the temperature of the upper part of the hot water storage tank 3 decreases (61 → 64). Thereafter, even if hot water supply or boiling operation is performed, the angle of temperature distribution does not change γ (β> α> γ) (64 → 65). This means that since there was no medium temperature hot water supply circuit, the temperature distribution that was slightly worsened by performing hot water in hot water operation mode could not be improved. As a result, the energy saving performance is impaired.

  Accordingly, since the intermediate temperature hot water supply circuit is provided, the hot water is poured in the hot water operation mode, the temperature distribution of the hot water storage tank 3 that is slightly broken can be improved, the lowering of the operation efficiency of the heat pump unit 2 can be avoided, and the energy is saved. Sex is not impaired.

(Embodiment 2)
FIG. 12 is a configuration diagram of a heat pump water heater in the second embodiment of the present invention.

  The difference of the second embodiment from the first embodiment is that the hot water return pipe 36 is shared with the boiling pipe 35, and the four-way switching valve 18a is replaced with the three-way switching valve 18b. That's right.

  Thus, according to the 2nd Embodiment of this invention, the hot water return pipe | tube 36 can be reduced and the same effect can be acquired at low cost.

  As described above, since the heat pump water heater according to the present invention is excellent in energy saving without impairing the comfort of the user, it can be applied to a hot water supply device for home use, and in a system having a heat source and a hot water storage tank. It can also be applied to business use.

DESCRIPTION OF SYMBOLS 1 Heat pump cycle 3 Hot water storage tank 4 Compressor 5 Water refrigerant | coolant heat exchanger 6 Pressure reducing means 7 Evaporator 9 1st hot water pipe 10 Medium temperature hot water pipe 11 Water supply pipe 12 Water supply branch part 13 2nd mixing valve (intermediate mixing valve)
14 Third mixing valve (hot water mixing valve)
15 First mixing valve (bath mixing valve)
16 Hot water branch pipe 17 Hot water junction pipe 18a Four-way switching valve 19 Hot water valve 20 Pressure reducing valve 21 Boiling pump 27 Bath pouring pipe 28 Hot water pipe 31 Bath 32 Heating pipe 33 Heating return pipe 40a-40e Hot water storage temperature detection means (Remaining hot water thermistor)
41 Incoming water temperature detecting means 42 Hot water temperature detecting means (hot water temperature sensor)
51 Control means

Claims (4)

A heat pump cycle connected with a compressor, a water refrigerant heat exchanger, a decompression means, an evaporator, a hot water storage tank for storing hot water heated in the heat pump cycle, and a hot water temperature detection means arranged in the water refrigerant heat exchanger A hot water storage temperature detection means, and a control means, and a hot water storage operation mode for storing hot water heated in the heat pump cycle in the hot water storage tank, and hot water having a temperature lower than at least the tapping temperature in the hot water storage operation mode. while heating produced by the heat pump cycle includes a hot beam operation mode for pouring the bath, and the melt-beam operation mode is the hot water heated by the heat pump cycle, once the hot water storage tank flowed, the after mixed with hot water in the hot water storage tank, a driving mode for supplying to the tub side, the detected temperature of the hot water storage temperature detecting means Tokoro When the temperature is less than the value, pouring into the bathtub is started in the hot water operation mode. On the other hand, when the detected temperature of the hot water storage temperature detecting means is higher than a predetermined value, the compressor is not operated. A heat pump hot water supply apparatus that starts pouring water into the bathtub using hot water stored in the hot water storage tank . In the hot water operation mode, a hot water return pipe for allowing hot water heated in the heat pump cycle to flow into the hot water storage tank, and an intermediate temperature hot water pipe connected between the upper and lower parts of the hot water storage tank are provided. The heat pump water heater according to claim 1, wherein the hot water return pipe is connected to an upper side of the hot water storage tank with respect to the intermediate temperature hot water pipe. The heat pump water heater according to claim 1 or 2, wherein, in the hot water operation mode, the heating capacity of the heat pump cycle is equal to or greater than the heating capacity in the hot water storage operation mode. The heat pump water heater according to claim 3, wherein in the hot water operation mode, the rotation speed of the compressor is equal to or higher than the rotation speed of the compressor in the hot water storage operation mode.