JP2017083045A - Heat pump water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump water heater having excellent power saving properties without damaging comfort and convenience of a user.SOLUTION: A heat pump water heater includes: hot water supply flow rate detection means (43a, 43b) for detecting a hot water supply flow rate from a hot water storage tank 3; hot water supply temperature detection means (47a, 47b) for detecting hot water supply temperature from the hot water storage tank 3; and hot water supply heat quantity calculation means 52 for calculating and storing the hot water supply heat quantity daily for each time zone from the hot water supply flow rate and the hot water supply temperature. The heat pump water heater executes a boiling operation for heating hot water to a predetermined temperature with predetermined heating power. The boiling operation in the late-night time zone includes a plurality of operation modes for operating at different heating capacities. The different heating capacities are set in such a manner that they become larger when the hot water supply heating quantity in the daily late-night time zone calculated and stored by the hot water supply heating quantity calculation means 52 is large than the time when it is small, and also they are substantially the same or less than the heating capacity in the daytime zone.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heat pump water heater.

  Conventionally, the control specifications for the boiling operation of this type of heat pump water heater include the following.

  FIG. 10 is a conceptual diagram of boiling operation control of a conventional heat pump water heater. As shown in FIG. 10, the heat pump hot water supply apparatus performs a boiling operation by the heat pump mainly in the inactive time zone and in the late-night time zone (for example, from 23:00 to 7:00 the next day) in which electricity is not used by other devices. The hot water stored in the hot water storage tank 3 is controlled by the user, and the user uses the hot water stored in the hot water storage tank 3 mainly in the daytime time zone (for example, 7:00 to 23:00) of the next day, which is the activity time zone.

  By matching the user's life pattern in this way, both the leveling of electricity usage for each time zone and the usability of the user are compatible. If the amount of hot water in the hot water storage tank 3 decreases and the risk of running out of hot water occurs, the heat pump may perform a boiling operation during the daytime period to suppress the risk of hot water running out.

  In the heat pump water heater designed as described above, the heating capacity of the heat pump is increased from the rated heating capacity only during the midnight hours to improve the efficiency during the night boiling operation of boiling the hot water in the entire hot water storage tank during the midnight hours. A control method has been devised to set the value to a lower value (for example, see Patent Document 1).

  It is possible to improve the energy efficiency of the heat pump water heater by obtaining the effect of improving the efficiency (COP) of the heat pump by lowering the heating capacity during boiling operation by making maximum use of the time corresponding to the midnight time zone. It is a possible configuration.

  The heating capacity of the heat pump in the midnight time zone is determined as follows.

  First, “the amount of heat required for boiling” is grasped at the start time 23:00 (first time) in the midnight time zone. The “boiling hot water amount” is calculated by subtracting the “remaining hot water amount” from the “hot water amount that needs to be stored” in the hot water storage tank 3 at 7:00 (second time) after the end time of the midnight time zone.

  Here, at 7:00 (second time) after the end time of the midnight time zone, “the amount of hot water that needs to be stored” is predicted based on the use record up to the previous day and the use record of the day, The more hot water that needs to be stored, the higher the boiling temperature is. Further, the “remaining hot water amount” is often obtained based on the temperature detected by the remaining hot water amount detecting means such as a remaining hot water thermistor.

  Next, when performing a heating operation with a heat pump with a rated heating capacity (for example, 4.5 kW), grasp the time required to secure the “heating required heat amount”, and follow the end time of the midnight time zone When boiling is completed a predetermined time (for example, 1 hour) or more before 7 o'clock, the heating capacity during boiling operation is set to a heating capacity lower than the rated heating capacity (for example, 3.6 kW). Understand the time required to secure the “boiling required heat” when operating.

At this time, if the boiling is completed before the predetermined time or longer, the boiling operation is performed with the determined heating capacity.If the boiling is not completed before the predetermined time or longer, the heating capacity during the boiling operation is rated. Boiling operation is performed with the heating capacity as it is.

  In addition, after starting boiling operation, when hot water is used and boiling cannot be completed more than a predetermined time before 7 o'clock the end of the midnight time zone, the heating capacity is greatly changed to raise Do the driving. This determination may be performed at a predetermined time after starting the boiling operation, or may be performed every time a predetermined time elapses.

  In addition, when the heat pump performs a boiling operation during the daytime, the heating capacity remains the rated heating capacity.

  As described above, when the heating operation by the heat pump is performed with a heating capacity lower than the rated heating capacity, it is determined whether or not the boiling can be completed more than a predetermined time before 7 o'clock the end time of the midnight time zone. Since the heating capacity of the heat pump is determined after that, the heat pump of the heat pump during boiling operation in the midnight time zone is suppressed while suppressing the occurrence of insufficient hot water storage due to incomplete boiling at 7:00 the next day after the end of the midnight time zone. COP can be improved and the energy efficiency as a heat pump hot-water supply apparatus can be improved.

JP 2010-127469 A

  However, in the conventional technology, when hot water is used during boiling operation at midnight, when the heating capacity is greatly changed during boiling operation, or when hot water is used in the latter half of midnight In addition, it may be necessary to increase the heating capacity beyond the rated heating capacity. Therefore, when the heating capacity is changed, a loss of transition of the operating point of the heat pump occurs, or in order to increase the heating capacity beyond the rated heating capacity, the differential pressure of the compressor is increased to lower the boiling efficiency. End up. Furthermore, when a large amount of hot water is used, the heating capacity is insufficient, and boiling cannot be completed within a predetermined time, and the amount of hot water is insufficient, which has the problem of impairing the usability of the user. .

  The present invention solves the above-described conventional problems, and an object thereof is to provide a heat pump hot water supply apparatus that is excellent in energy saving and that reduces the amount of medium-temperature water generated in a hot water storage tank and suppresses a decrease in reheating performance. And

  In order to solve the conventional problem, a heat pump water heater of the present invention includes a heat pump cycle including a compressor and a water refrigerant heat exchanger, a hot water storage tank for storing hot water heated by the water refrigerant heat exchanger, Hot water flow rate detection means for detecting the hot water flow rate from the hot water storage tank, hot water temperature detection means for detecting the hot water temperature from the hot water storage tank, hot water flow rate detected by the hot water flow rate detection means and the hot water temperature detection means Hot water supply calorie calculating means for calculating and storing hot water supply heat amount for each time period from the hot water supply temperature, and control means, the control means operates the compressor, with a predetermined heating capacity, A boiling operation in which hot water is heated to a predetermined temperature in a water-refrigerant heat exchanger is executed, and the boiling operation in the midnight time zone includes a plurality of operation modes that are operated with different heating capacities. Thus, the different heating capacity is substantially larger than the heating capacity in the daytime period so that the heating capacity becomes larger when the hot water heating quantity in the daily midnight time zone calculated and stored by the hot water supply calorie calculating means is larger when it is small. It is characterized by being set to be equal or less.

  By determining the heating capacity based on daily hot water usage in the midnight hours, hot water expected to be used after the start of boiling operation can be boiled up in the midnight hours. It is possible to suppress the occurrence of efficiency loss by changing the heating capacity during operation, or the shortage of the heating capacity for completion of boiling due to the use of a large amount of hot water.

  As a result, while setting the heating capacity of the heat pump low based on the amount of hot water used in the midnight hours to improve COP, the heating capacity change is reduced to improve the boiling efficiency, and a large amount of hot water The heat pump hot water supply apparatus which suppresses the risk of running out of hot water when used and can achieve both energy saving and user usability can be provided.

  ADVANTAGE OF THE INVENTION According to this invention, the heating capability of the heat pump cycle in a midnight time zone can be set low, and the heat pump hot water supply apparatus excellent in energy saving property can be provided, without impairing a user's usability.

The figure which shows an example of the change of the heating capability of the heat pump cycle at the time of the boiling operation according to the usage pattern of the hot water by the user in Embodiment 1 of this invention The block diagram of the heat pump hot-water supply apparatus in Embodiment 1 of this invention (A) Top sectional view of heat pump unit in Embodiment 1 of the present invention (b) Front sectional view of heat pump unit in Embodiment 1 of the present invention The figure which shows the flowchart of the setting of the heating capability of the heat pump cycle at the time of the boiling operation in Embodiment 1 of this invention The figure which shows the time-dependent change of the tapping temperature after the boiling operation start by the same heat pump cycle The figure which shows the time-dependent change of the rotation frequency and tapping temperature of the compressor of the heat pump cycle Diagram showing the distribution of medium temperature water in the hot water storage tank The figure which shows the relationship between the heating capacity and COP of the same heat pump cycle (A) Top sectional view of the other heat pump unit (b) Front sectional view of the other heat pump unit The figure which shows an example of the usage pattern of the hot water by the conventional user, and the state of the heating capability of the heat pump cycle at the time of boiling operation according to it

  A first invention is a heat pump cycle including a compressor and a water refrigerant heat exchanger, a hot water storage tank for storing hot water heated by the water refrigerant heat exchanger, and a hot water supply flow rate for detecting a hot water supply flow rate from the hot water storage tank. A hot water supply temperature detecting means for detecting a hot water supply temperature from the hot water storage tank, a hot water supply flow rate detected by the hot water supply flow rate detecting means, and a hot water supply temperature detected by the hot water supply temperature detecting means for each daily time zone Hot water supply calorific value calculation means for calculating and storing heat quantity, and control means, wherein the control means operates the compressor and has hot water at a predetermined temperature in the water / refrigerant heat exchanger with a predetermined heating capacity. The boiling operation in the midnight time zone includes a plurality of operation modes that operate at different heating capacities, and the different heating capacities are calculated by the hot water supply calorie calculating means. It is characterized in that it is set to be greater when the amount of hot water supply in the daily midnight time zone to be calculated is larger than when it is small, and to be approximately equal to or less than the heating capacity in the daytime time zone. It is a heat pump hot water supply device.

By determining the heating capacity based on daily hot water usage in the midnight hours, hot water expected to be used after the start of boiling operation can be boiled up in the midnight hours. It is possible to suppress the occurrence of efficiency loss by changing the heating capacity during operation, or the shortage of the heating capacity for completion of boiling due to the use of a large amount of hot water.

  As a result, while setting the heating capacity of the heat pump low based on the amount of hot water used in the midnight hours to improve COP, the heating capacity change is reduced to improve the boiling efficiency, and a large amount of hot water The heat pump hot water supply apparatus which suppresses the risk of running out of hot water when used and can achieve both energy saving and user usability can be provided.

  In a second aspect of the invention, in particular, in the first aspect of the invention, the control means sets the rotation speed of the compressor at the start of the boiling operation in the midnight time zone to the water refrigerant heat exchanger in the same time zone. In the heat pump hot water supply apparatus, the temperature of the heated hot water is set to be higher than the rotation speed of the compressor when the temperature reaches a target temperature.

  As a result, the temperature of the hot water heated by the water-refrigerant heat exchanger can be increased faster since the temperature of the compressor and the water-refrigerant heat exchanger can be increased quickly when starting the boiling operation at midnight. Since the target boiling temperature can be reached and the amount of medium-temperature water to be generated can be further reduced, the decrease in the temperature of the hot water in the hot water storage tank is suppressed and the reheating performance is improved. Cutting risk can be reduced.

  A third invention is a heat pump hot water supply apparatus characterized in that, in the first or second invention, a heat insulating material is provided in the compressor and / or the water refrigerant heat exchanger. .

  Thereby, since the temperature of a compressor and a water refrigerant | coolant heat exchanger can be raised still more rapidly, the temperature of the hot water heated with the water refrigerant | coolant heat exchanger can also be made to reach a target boiling temperature more quickly.

  In a fourth aspect of the present invention, in particular, in any one of the first to third aspects, at least a part of the compressor and the water-refrigerant heat exchanger are disposed in the same partitioned space in the housing. It is the heat pump hot-water supply apparatus characterized by having.

  As a result, when starting the heating operation at midnight, a part of the heat radiated from the compressor is received by the water refrigerant heat exchanger, and the temperature of the water refrigerant heat exchanger can be increased more quickly. The hot water heated by the water-refrigerant heat exchanger can reach the target boiling temperature faster, and the amount of medium-temperature water to be generated can be reduced. It is possible to suppress a decrease in the temperature of hot water, improve the reheating performance, and reduce the risk of running out of hot water.

  In a fifth aspect of the present invention, in particular, in any one of the first to fourth aspects of the invention, the heat pump cycle is a heat pump hot water supply device that operates in a supercritical state of refrigerant on the high pressure side.

  This makes it possible to increase the COP when the heat pump cycle boils hot water at a high temperature. Therefore, even when the heating capacity of the heat pump cycle is set low in the midnight heating operation, boiling by the heat pump cycle is efficient. Since the raising operation can be performed, the energy efficiency of the heat pump water heater can be increased.

  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. 2 is a diagram illustrating a configuration of the heat pump hot water supply apparatus according to the first embodiment of the present invention. The heat pump hot water supply apparatus includes a heat pump unit 2a and a hot water storage unit 2b.

  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 piping 32, the water refrigerant heat exchanger 5, the boiling return piping 33, the three-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 three-way switching valve 18a. One outlet of the three-way switching valve 18a is connected to a substantially bottom portion of the hot water storage tank 3 by a boiling bypass pipe 34, and the other outlet of the three-way switching valve 18a is connected to a substantially top portion of the hot water storage tank 3 through a boiling piping 35. It is connected.

  That is, the hot water in the boiling return pipe 33 conveyed by the boiling pump 21 is switched between the case of returning to the substantially bottom portion of the hot water storage tank 3 and the case of returning to the approximate top portion of the hot water storage tank 3 by the three-way switching valve 18a. Can be done.

  Further, the water inlet temperature detection means 41 that is a water temperature sensor that detects the water temperature at the inlet is provided at the water side inlet of the water refrigerant heat exchanger 5, and the hot water temperature that is a hot water temperature sensor that detects the water temperature at the outlet at the water side outlet. Detection means 42 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 is supplied to the hot water storage tank 3, a third mixing valve 14, and a first mixing valve 15, which will be described later, via a water supply pipe 11 to which a pressure reducing valve 20 is connected. 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. The water supply pipe 11 is provided with a water supply temperature sensor 53 for detecting the water supply temperature.

  A first hot water discharge pipe 9 is provided at the upper part of the hot water storage tank 3, and an intermediate temperature hot water supply is provided at a position below the position where the first hot water discharge pipe 9 is connected in the vertical direction of the hot water storage tank 3 and above the bottom of the hot water storage tank 3. Tubes 10 are connected to each other. 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. This 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 hot water supply pipe 28 is provided with a hot water supply flow rate sensor 47a as a first hot water supply flow rate detection means.

  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 pouring pipe 27 is provided with a bath hot water flow rate sensor 47b as second hot water flow rate detecting means.

  Hot water pouring into the bathtub 31 using the first mixing valve 15 can be started by operating a remote controller 50 as setting operation means (for example, pressing a bath automatic hot water button). When bath remote hot water is instructed from the remote controller 50 to the control means 51, the control means 51 opens the pouring valve 19 and pours water into the bathtub 31 through the first mixing valve 15 and the bath pouring pipe 27.

  52 is a hot water supply calorie calculating means for calculating and storing the daily heat amount from the temperature and flow rate of hot water flowing out from the hot water supply pipe 28 and the bath pouring pipe 27.

  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 outlet pipe 29, and the bathtub 31 are connected in a ring shape.

  Further, in the middle of the return pipe 26, in the middle of the return temperature sensor 44 for detecting the temperature of hot water returning from the bath heat exchanger 24 to the hot water storage tank 3 through the follow pump 22, and in the middle of the bath return pipe 30. Are provided with a bath temperature sensor 45 as a bath temperature detecting means for detecting a hot water temperature in the bathtub 31 and a water level sensor 46 as a bathtub water level detecting means.

  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.

FIG. 3 is a front view of the inside of the heat pump unit 2a. Reference numeral 101 denotes a compressor heat insulating material, which is provided by being wound around the outer periphery of the compressor 4. The compressor heat insulating material 101 plays a role of suppressing heat leakage from the outer peripheral surface of the compressor to the outside of the heat pump unit 2a through the machine room 200. The compressor heat insulating material 101 may be made of a material having a sound absorbing effect in addition to the heat insulating effect.

  Reference numeral 102 denotes a water refrigerant heat exchanger heat insulating material, which is provided so as to cover the water refrigerant heat exchanger 5 and plays a role of suppressing heat leakage from the water refrigerant heat exchanger 5 to the outside.

  About the heat pump hot-water supply apparatus comprised as mentioned above, the operation | movement is demonstrated.

  The basic boiling operation control method is the same as that of the conventional heat pump water heater, and the refrigerant is compressed to a high pressure by the compressor 4 mainly in the late-night time zone, which is the inactive time zone, and the high-pressure and high-temperature refrigerant. Then, the water conveyed from the substantially lower part of the hot water storage tank 3 is heated by the water-refrigerant heat exchanger 5 and returned to the substantially upper part of the hot water storage tank 3 to perform the boiling operation by the heat pump cycle 1, and the daytime of the next day. Prepare for hot water use in time.

  In the heat pump cycle 1, the fan 8 is rotated to supply air (heat) to the refrigerant flowing in the evaporator 7, and the refrigerant discharged from the compressor 4 is reduced by the decompression means 6 such as an expansion valve. The temperature is adjusted.

  FIG. 4 shows a control flowchart of the heating operation in the midnight time zone. As with conventional heat pump water heaters, we know the amount of hot water that needs to be stored for the next day, which is predicted from past usage results, and the amount of remaining hot water before the start of boiling operation at midnight. (Step 1).

  The “remaining hot water amount” is grasped by using at least one of the temperatures detected by the remaining hot water thermistors 40 a to 40 e installed on the wall surface of the hot water storage tank 3.

  For example, using the remaining hot water thermistor 40c and the remaining hot water thermistor 40d disposed between the substantially central portion and the bottom in the height direction of the hot water storage tank 3, the temperature difference (Tc−Td) between these values can be obtained. When the value Td of the remaining hot water thermistor 40d below the predetermined value α (for example, 3 deg) exceeds the predetermined value β (for example, 60 ° C.), the remaining hot water thermistor 40d is removed from the top surface of the hot water storage tank 3. It can be determined that there is hot water to the position.

  When the temperature of the remaining hot water thermistor 40d is 60 ° C. or less, it is determined that the amount of remaining hot water is small. On the other hand, when the temperature of the remaining hot water thermistor 40d is higher than 60 ° C., the remaining hot water thermistor 40d It can be determined that there is hot water to the position.

  Although it is more accurate to calculate the “remaining hot water amount” using a plurality of remaining hot water thermistors, in this way, in the hot water storage tank 3, a temperature stratified type hot water storage in which the upper side is hotter than the lower side is stored. In the tank 3, it is desirable to determine the temperature using the temperature of the remaining hot water thermistor 40 d disposed at least between approximately the center and the bottom in the height direction of the hot water storage tank 3.

  Subsequently, the hot water supply heat amount calculation means is calculated from the hot water supply temperature detected by the hot water supply temperature sensor 45, the hot water supply temperature detected by the hot water supply temperature sensor 43a and the hot water supply temperature sensor 43b, and the hot water supply flow rate detected by the hot water supply flow rate sensor 47a and the hot water supply flow rate sensor 47b. Based on the amount of hot water used in the past midnight time zone calculated and stored by 52, the “amount of hot water used in the midnight time zone” of the day is estimated (step 2).

  After that, in addition to “the amount of hot water that needs to be stored” and “the amount of remaining hot water” obtained in (step 1), using “the amount of hot water used in midnight” estimated in (step 2), The necessary amount of hot water is grasped (step 3).

  The remaining hot water amount stored in the hot water supply calorie calculating means 52 based on the height from the top of the hot water storage tank 3 to the remaining hot water thermistor determined to have hot water is calculated from “the amount of hot water that needs to be stored”. By subtracting and adding the estimated “amount of hot water used in the midnight hours”, it is possible to grasp the “amount of hot water required for boiling”.

  Next, the heat pump cycle grasps the required time t1 when the heating capacity is Q1 and the boiling operation is performed to secure the “boiling required hot water amount” (step 4).

  It is determined whether or not the boiling operation completion time predicted from the required time t1 is earlier than a predetermined time (for example, 1 hour) by 7 hours following the end time of the midnight time zone (step 5).

  If the "boiling required amount of hot water" is appropriate for the heating capacity Q1 and the predicted boiling operation completion time is more than a predetermined time earlier than the end time of the midnight time zone, the heat pump cycle sets the heating capacity to Q1. A boiling operation is performed (step 6).

  If the “boiling required hot water volume” is excessive with respect to the heating capacity Q1, and the predicted boiling operation completion time does not advance more than a predetermined time with respect to the end time of the midnight time zone, the heat pump cycle sets the heating capacity to Q2. The required time t2 when the boiling operation is performed to ensure the “boiling required hot water amount” is grasped (step 7). Here, heating capacity Q2> heating capacity Q1.

  It is determined whether or not the boiling operation completion time predicted from the required time t2 is a predetermined time (for example, 1 hour) or more earlier than 7 o'clock the next midnight end time (step 8).

  When the “boiling required hot water amount” is appropriate for the heating capacity Q2 and the predicted boiling operation completion time is earlier than the end time of the midnight time period by a predetermined time or more, the heat pump cycle sets the heating capacity to Q2. A boiling operation is performed (step 9).

  If the “boiling required hot water volume” is excessive with respect to the heating capacity Q2, and the predicted boiling operation completion time does not advance more than a predetermined time with respect to the end time of the midnight time zone, the heat pump cycle sets the heating capacity to Q3. A boiling operation is performed (step 10). Here, the heating capacity Q3> the heating capacity Q2, and the heating capacity Q3≈the rated heating capacity may be satisfied.

  FIG. 1 is a diagram illustrating an example of a hot water usage pattern by a general user and a heating operation pattern of a heat pump hot water supply apparatus corresponding thereto.

  Similar to the conventional heat pump hot water supply apparatus, it is controlled to perform boiling operation by the heat pump mainly at midnight and store hot water in the hot water storage tank 3, but when starting the boiling operation at midnight, FIG. The heating capacity of the heat pump is determined as Q2 from the “boiling hot water amount” calculated according to the flowchart shown.

  As a result, the heating operation of the heat pump in the midnight time zone is performed with the heating capability Q2 smaller than the rated heating capability.

  The heating capacity of the heat pump cycle 1 increases as the amount of hot water used in the midnight time zone predicted by the hot water supply calorific value calculation means 52 increases, and the heating capability of the heat pump cycle 1 decreases as the amount of hot water used in the predicted midnight time zone decreases. The boiling operation will be performed.

  Further, the smaller the heating capacity of the heat pump cycle 1 is, the lower the target value of the boiling temperature of the hot water supplied to the hot water storage tank 3 is heated by the water refrigerant heat exchanger 5 of the heat pump cycle 1 is set. Yes.

  FIG. 8 is a diagram showing the relationship between the heating capacity of the heat pump cycle 1 and the COP. The COP tends to increase as the heating capacity decreases.

  In the case of the heating operation pattern shown in FIG. 1, the heating operation by the heat pump is performed with high energy consumption efficiency with COP2 (> COP3) as the COP related to the heating operation in the midnight time zone.

  Since heat pump cycle 1 uses carbon dioxide as a refrigerant and is operated in a supercritical state on the high pressure side, it is efficient when boiling hot water at a high temperature (for example, 65 to 90 ° C.). .

  Further, even when the boiling operation is performed with the heating capacity reduced, the refrigerant is similarly operated in a supercritical state, so that hot water can be efficiently generated.

  FIG. 5 is a diagram showing a change with time in the tapping temperature after the start of the boiling operation by the heat pump cycle.

  Immediately after the start of the boiling operation by the heat pump cycle, it is necessary to raise the temperature of the compressor 4 and the water / refrigerant heat exchanger 5 itself, and it takes a certain time for the tapping temperature to reach the target boiling temperature.

  During this fixed time, while the heat of the compressor 4 and the water / refrigerant heat exchanger 5 is increased, the hot water temperature of the heat pump cycle 1 is temporarily set to a medium temperature (for example, 20 to 50 ° C.). Degree) and reach the target boiling temperature.

  In general, when the heating capacity of the heat pump cycle 1 is reduced, the COP is improved as described above, but the time until the tapping temperature reaches the target boiling temperature is significantly increased.

  This is because the amount of heat released from components such as the compressor 4 and the water refrigerant heat exchanger 5 does not depend on the size of the heating capacity of the heat pump cycle 1 depending on the temperature of the components, so the heating capacity is small. This is because the relative ratio of the heat dissipation amount to the heating capacity is increased.

  However, in the heat pump hot water supply apparatus of the present invention, since the heat insulating material is provided in the component parts such as the compressor 4 and the water-refrigerant heat exchanger 5 and the heat radiation from the component parts to the outside is suppressed as much as possible, the heating capacity is reduced. Even in this case, the hot water temperature can reach the target boiling temperature in a short time after the boiling operation is started.

  Furthermore, as shown in FIG. 6, in the heat pump hot water supply apparatus of the present invention, the rotation speed of the compressor 4 at the start of the boiling operation is the rotation when the tapping temperature becomes the target boiling temperature and the steady state is reached. The temperature of the components such as the compressor 4 and the water / refrigerant heat exchanger 5 is increased in a short time, and the boiling temperature is set to the target boiling temperature in a short time after starting the boiling operation. To reach.

  By doing in this way, the quantity of the middle temperature water produced | generated after a boiling operation start can be suppressed.

  Therefore, by insulating the compressor 4 and the water-refrigerant heat exchanger 5, it is possible to suppress the hot water temperature in the hot water storage tank 3 from being lowered by the generated hot water even if the heating capacity is reduced according to the boiling temperature. COP can be improved by reducing the heating capacity without lowering the hot water temperature and increasing the time required to replenish the hot water in the bathtub, or without running out of hot water on days when hot water usage is high. It is possible to achieve both user convenience and energy saving.

  Further, since the heating capacity in the midnight time zone is reduced according to the “boiling hot water amount”, the influence of the generated intermediate temperature water on the hot water existing in the hot water storage tank 3 is different.

  FIG. 7 is a diagram showing a change in temperature distribution in the hot water storage tank 3 for each “boiling hot water amount”.

  When the amount of hot water required for boiling is large, the amount of remaining hot water in the hot water storage tank 3 is small and the boiling operation is performed at the rated heating capacity. Therefore, the hot water is generated at the start of the boiling operation and is stored in the hot water storage tank 3. The amount of medium temperature water supplied is relatively small.

  In addition, since the amount of remaining hot water in the hot water storage tank 3 is small, and after the boiling operation is started, a lot of hot water is boiled and stored after the hot water temperature reaches the target boiling temperature. By insulating the components such as the heat exchanger 5, the temperature of the hot water storage tank 3 can be increased as compared with the case where no heat insulating material is provided, although the influence of the moderately warm water to be suppressed is relatively small. .

  On the other hand, when “the amount of hot water required for boiling” is small, the amount of remaining hot water in the hot water storage tank 3 is large and the heating capacity is reduced to Q1, and the boiling operation is performed. Although it is easy to produce | generate, the quantity of the intermediate temperature water produced | generated can be suppressed by thermally insulating components, such as the compressor 4 and the water refrigerant heat exchanger 5, with a heat insulating material.

  In addition, the amount of remaining hot water in the hot water storage tank 3 is small, and after the boiling operation starts, after the tapping temperature reaches the target boiling temperature, only a relatively small amount of hot water is boiled to store hot water. Therefore, the influence of the heat insulating material on the production of intermediate temperature water and the hot water in the hot water storage tank 3 can be greatly suppressed. As a result, the temperature in the hot water storage tank 3 can be significantly increased.

  When a heat insulating material is not provided in the compressor 4 and the water-refrigerant heat exchanger 5, as shown in FIG. 5, when the boiling operation is performed at the rated heating capacity, the tapping temperature reaches the target boiling temperature. Although the time is not significantly different from the case where a heat insulating material is provided, when the heating operation is reduced and the boiling operation is performed, the time until the tapping temperature reaches the target boiling temperature is significantly increased.

  When the hot water in the hot water storage tank 3 is small, the boiling operation is performed with the rated heating capacity, so the amount of intermediate temperature water generated does not increase much more than the case where a heat insulating material is provided, and is also affected by the intermediate temperature water. Since the amount of hot water is small, the effect is relatively small, but when there is a lot of hot water in the hot water storage tank 3, the heating capacity is reduced and the boiling operation is performed, so the amount of medium-temperature water produced is not provided with heat insulation Since the amount of hot water affected by the medium-temperature water is large, the effect is very large.

Therefore, by insulating the compressor 4 and the water refrigerant heat exchanger 5, the hot water temperature in the hot water storage tank 3 is lowered by the generated hot water even if the heating capacity is reduced according to the remaining hot water amount in the hot water storage tank 3. As the temperature of the hot water drops, the time required to replenish the hot water in the bathtub is prolonged, and the heating capacity is reduced without causing hot water to run out on days when hot water usage is high. The COP improvement effect by can be obtained, and both user convenience and energy saving can be achieved.

  9 is a front view and a top view of the inside of the heat pump unit 2a different from FIG.

  3 differs from FIG. 3 in that both the compressor 4 and the water-refrigerant heat exchanger 5 are disposed in a machine room 200 partitioned from a blower circuit through which air flows as the fan 8 rotates. is there.

  By doing in this way, since the heat radiation from the compressor 4 can be received by the water refrigerant heat exchanger 5, the temperature of the water refrigerant heat exchanger 5 is raised in a short time at the start of the boiling operation. It is possible to suppress the amount of medium-temperature water to be generated.

  According to this, since the amount of the intermediate warm water to be generated can be reduced at the start of the boiling operation, the temperature drop of the hot water in the hot water storage tank 3 is suppressed, and the reheating performance and the like are not deteriorated. The heating capacity can be reduced to achieve both user convenience and energy saving.

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

DESCRIPTION OF SYMBOLS 1 Heat pump cycle 2a Heat pump unit 2b Hot water storage unit 3 Hot water storage tank 4 Compressor 5 Water refrigerant | coolant heat exchanger 6 Decompression means 7 Evaporator 8 Fan 40a-40e Hot water storage temperature detection means (remaining hot water thermistor)
43a Hot water temperature detection means (hot water temperature sensor)
43b Hot water temperature detection means (bath hot water temperature sensor)
47a Hot water flow rate detection means (hot water flow rate sensor)
47b Hot water flow rate detection means (bath hot water flow rate sensor)
51 Control means 52 Hot water supply calorie calculation means

Claims (5)

A heat pump cycle including a compressor and a water refrigerant heat exchanger;
A hot water storage tank for storing hot water heated by the water refrigerant heat exchanger;
Hot water flow rate detecting means for detecting the hot water flow rate from the hot water storage tank;
Hot water supply temperature detecting means for detecting hot water supply temperature from the hot water storage tank;
Hot water supply heat amount calculation means for calculating and storing hot water supply heat amount for each daily time zone from the hot water supply flow rate detected by the hot water supply flow rate detection means and the hot water supply temperature detected by the hot water supply temperature detection means;
Control means;
With
The control means operates the compressor, performs a boiling operation of heating hot water to a predetermined temperature in the water refrigerant heat exchanger with a predetermined heating capacity, and
The boiling operation in the midnight time zone includes a plurality of operation modes that operate with different heating capacities,
The different heating capacity is substantially equal to or less than the heating capacity in the daytime period so that the heating capacity is larger when the hot water heating quantity in the daytime midnight time period calculated and stored by the hot water supply calorie calculating means is smaller. The heat pump hot water supply apparatus characterized by being set so that it may become. The control means determines the rotation speed of the compressor at the start of the boiling operation in the midnight time zone when the temperature of the hot water heated by the water-refrigerant heat exchanger reaches the target temperature in the same time zone. The heat pump hot water supply apparatus according to claim 1, wherein the heat pump hot water supply apparatus is set to be higher than a rotation speed of the compressor. The heat pump hot water supply apparatus according to claim 1 or 2, wherein a heat insulating material is provided in the compressor and / or the water refrigerant heat exchanger. The said compressor and at least one part of the said water-refrigerant heat exchanger are arrange | positioned in the same space divided within the housing | casing, The said any one of Claims 1-3 characterized by the above-mentioned. Heat pump water heater. The heat pump hot water supply device according to any one of claims 1 to 4, wherein the heat pump cycle operates in a supercritical state of refrigerant on a high pressure side.

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