Heat pump type water heating device

Abstract

To provide a heat pump type water heating device that has good efficiency of annual supplied-hot-water heat insulation.SOLUTION: A heat pump type water heating device includes: a heat pump unit 200 having a compressor 201 and a water refrigerant heat exchanger 202; and a hot water storage unit 100 having a first tank 101 with a hot water tapping port through which hot water flows out provided in an intermediate portion, a second tank 102 connected to the first tank 101 via a connection pipe 114, and a heat exchanger 103 to exchange heat between the hot water flowing out from the first tank and hot water in a bathtub 301. A return port 105 for returning the hot water flowing out from the heat exchanger 103 is provided at any position on the first tank 101 or a position in the second tank 102 that is higher than the bottom part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a heat pump water heater. [Background technology]

[0002] Conventionally, twin-tank heat pump water heaters have been known, each equipped with a first tank for storing hot water to be dispensed into a bathtub or hot water supply terminal, and a second tank for storing water supplied from city water. Some of these heat pump water heaters are capable of intermediate hot water dispensing, which dispenses hot water from the middle of the first tank. Some of these heat pump water heaters are also capable of reheating, which heats the hot water in the bathtub to a predetermined temperature by exchanging heat between the hot water in the first tank and the hot water in the bathtub. In models capable of reheating, a return port is provided at the bottom of the second tank, and the hot water that leaves the first tank and whose temperature has been reduced by heat exchange is returned to the second tank through the return port. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-169584 Summary of the Invention [Problem to be solved by the invention]

[0004] The heat pump water heater described above has a problem of poor annual hot water supply and insulation efficiency (APF). In view of the above problem, the present disclosure aims to provide a heat pump water heater with good annual hot water supply and insulation efficiency. [Means for solving the problem]

[0005] A heat pump water heater according to one embodiment of the present disclosure includes a heat pump unit having a compressor and a water-refrigerant heat exchanger, a hot water storage unit having a first tank having a hot water outlet located in the middle thereof from which hot water flows, a second tank connected to the first tank by a connecting pipe, and a heat exchanger that exchanges heat between the hot water flowing out of the first tank and the hot water in the bathtub.The heat pump water heater according to one embodiment of the present disclosure is characterized in that a return port is provided at any position in the first tank or at a position above the bottom of the second tank for returning the hot water flowing out of the heat exchanger into the tank. [Effects of the Invention]

[0006] The heat pump water heater according to the present disclosure has a return port at a position in the first tank or at a position above the bottom of the second tank for returning the hot water flowing out from the heat exchanger into the tank. Therefore, the heat pump water heater according to the present disclosure has good year-round hot water supply and insulation efficiency. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an overall configuration diagram illustrating a heat pump hot water supply device according to a first embodiment. [Figure 2] Diagram explaining the heating circuit during heating operation [Figure 3] A diagram explaining the normal hot water discharge circuit during normal hot water discharge operation [Figure 4] A diagram explaining the intermediate hot water discharge circuit during intermediate hot water discharge operation [Figure 5] Flowchart diagram showing switching between normal hot water discharge operation and intermediate hot water discharge operation [Figure 6] Diagram explaining the reheating circuit during reheating operation [Figure 7] FIG. 10 is an overall configuration diagram illustrating a heat pump hot water supply device according to a second embodiment. [Figure 8] Diagram explaining the reheating circuit during reheating operation DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of a heat pump water heater according to the present disclosure will be described with reference to the drawings. Note that the embodiments disclosed below are all examples and are not intended to impose limitations on the heat pump water heater according to the present disclosure.

[0009] Furthermore, in the embodiments disclosed below, unnecessary detailed explanations may be omitted. For example, detailed explanations of well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the explanations and to facilitate understanding by those skilled in the art.

[0010] <First Embodiment> A heat pump hot water supply device according to a first embodiment will be described.

[0011] Fig. 1 is an overall configuration diagram illustrating a heat pump hot water heater according to Embodiment 1. The overall configuration of the heat pump hot water heater will be described using Fig. 1.

[0012] The heat pump hot water supply device according to the first embodiment includes a hot water storage unit 100 and a heat pump unit 200.

[0013] The hot water storage unit 100 includes a first tank 101, a second tank 102, and a heat exchanger 103 (reheating heat exchanger).

[0014] First tank 101 stores hot water to be dispensed into bathtub 301, hot water supply terminal 302, etc. First tank 101 has, for example, a long cylindrical middle section arranged so that the cylindrical axis is parallel to the vertical direction, a substantially hemispherical top section that closes the upper end opening of the middle section, and a substantially hemispherical bottom section that closes the lower end opening of the middle section. In first tank 101, the middle section is a section with a substantially constant outer diameter, the top section is a section where the outer diameter gradually decreases upward, and the bottom section is a section where the outer diameter gradually decreases downward.

[0015] A hot water outlet 104 (intermediate hot water outlet) through which hot water flows out is provided in the middle of the first tank 101. Specifically, the hot water outlet 104 is provided at a position below the third temperature measurement unit 117 and above the fourth temperature measurement unit 118.

[0016] A return port 105 is provided in the middle of the first tank 101 to return the hot water flowing out from the heat exchanger 103 into the first tank 101. Specifically, the return port 105 is provided in approximately the center of the middle part in the up-down direction, at a position below the second temperature measurement unit 116 and above the third temperature measurement unit 117. Furthermore, the return port 105 is provided in a position above the hot water outlet 104.

[0017] Furthermore, a first temperature measurement unit 115, a second temperature measurement unit 116, a third temperature measurement unit 117, and a fourth temperature measurement unit 118 are provided in the middle of the first tank 101 to measure the temperature of the hot water stored in the first tank 101. The first temperature measurement unit 115, the second temperature measurement unit 116, the third temperature measurement unit 117, and the fourth temperature measurement unit 118 are provided at different height positions in that order from top to bottom.

[0018] More specifically, the first temperature measuring unit 115 is provided at the upper end of the intermediate section and measures the lower limit temperature of the hot water in the top section located above the intermediate section. The second temperature measuring unit 116 is provided above the return port 105 and measures the upper limit temperature of the hot water returned from the return port 105. The third temperature measuring unit 117 is provided below the return port 105 and below the outlet 104. The fourth temperature measuring unit 118 is provided below the hot water outlet 104 and measures the lower limit temperature of the hot water that flows out of the hot water outlet 104. The fourth temperature measuring unit 118 is provided below the hot water outlet 104 and measures the lower limit temperature of the hot water that flows out of the hot water outlet 104.

[0019] Four temperature measurement units, namely, a first temperature measurement unit 115, a second temperature measurement unit 116, a third temperature measurement unit 117, and a fourth temperature measurement unit 118, are used to measure the temperature distribution in the entire first tank.

[0020] A relief valve 139 is connected to the top of the first tank 101 to release pressure when the inside of the first tank 101 becomes overpressurized.

[0021] The bottom of the first tank 101 is connected to the top of the second tank 102 via a connecting pipe 114 .

[0022] The second tank 102 stores water supplied from city water. The second tank 102 has, for example, a long cylindrical middle section arranged so that the cylindrical axis is parallel to the vertical direction, a substantially hemispherical top section that closes the upper opening of the middle section, and a substantially hemispherical bottom section that closes the lower opening of the middle section. In the second tank 102, the middle section is a section with a substantially constant outer diameter, the top section is a section where the outer diameter gradually decreases upward, and the bottom section is a section where the outer diameter gradually decreases downward.

[0023] A fifth temperature measuring unit 119 and a feed water temperature measuring unit 120 are provided in the middle of the second tank 102. The fifth temperature measuring unit 119 is disposed at a position higher than the feed water temperature measuring unit 120.

[0024] The bottom of the first tank 101 and the bottom of the second tank 102 are each connected to a drain plug 140 .

[0025] The heat exchanger 103 exchanges heat between the hot water stored in the first tank 101 and the hot water in the bathtub 301 .

[0026] The heat pump unit 200 includes a compressor 201 , a water-refrigerant heat exchanger 202 , a pressure reducer 203 , an evaporator 204 , a fan 205 , a heat pump pipe 206 , and an outside air temperature measuring unit 209 .

[0027] The compressor 201 applies pressure to the refrigerant, thereby increasing the temperature and pressure of the refrigerant.

[0028] The water-refrigerant heat exchanger 202 exchanges heat between the refrigerant that has been heated to a high temperature and pressure by the compressor 201 and the water that has flowed in from the bottom of the second tank 102 .

[0029] The pressure reducer 203 expands the refrigerant from which heat has been removed by the heat exchange in the water-refrigerant heat exchanger 202, thereby lowering the temperature of the refrigerant.

[0030] The evaporator 204 is an air-refrigerant heat exchanger for making the refrigerant, whose temperature has been lowered by the pressure reducer 203, take in heat from the atmosphere.

[0031] A fan 205 supplies air to the evaporator 204 so that the refrigerant efficiently absorbs heat from the atmosphere.

[0032] The heat pump pipe 206 connects the compressor 201, the water-refrigerant heat exchanger 202, the pressure reducer 203, and the evaporator 204 in a ring shape.

[0033] The outside air temperature measuring unit 209 is provided in the evaporator 204 or in the vicinity thereof, and detects the outside air temperature.

[0034] The operation of the heat pump water heater is controlled by a bathroom remote control 303, a kitchen remote control 305, or an additional remote control 306.

[0035] The heat pump water heater according to the first embodiment as described above is capable of performing boiling operation, normal hot water supply operation, intermediate hot water supply operation, and additional heating operation. Next, each operation will be described.

[0036] (Heating operation) Fig. 2 is a diagram illustrating the boiling circuit during boiling operation. The boiling circuit is shown by a thick line in Fig. 2.

[0037] 2, during the boiling operation, a boiling circuit is formed in which the first tank 101, the second tank 102, and the water-refrigerant heat exchanger 202 of the heat pump unit 200 are connected in a ring shape by the connecting pipe 114 and the boiling pipe 108. During the boiling operation, water or hot water circulates through the boiling circuit in the order of the first tank 101, the second tank 102, and the water-refrigerant heat exchanger 202.

[0038] As described above, the bottom of the first tank 101 and the top of the second tank 102 are connected by the connecting pipe 114. In addition, the bottom of the second tank 102 and the water-refrigerant heat exchanger 202, and the water-refrigerant heat exchanger 202 and the top of the first tank 101 are connected by the boiling pipe 108.

[0039] A boiling pump 122 is provided in a portion of the boiling pipe 108 between the second tank 102 and the water-refrigerant heat exchanger 202. The boiling pump 122 sends water from the bottom of the second tank 102 to the water-refrigerant heat exchanger 202.

[0040] An inlet water temperature measuring unit 207 is provided in the boiling pipe 108 upstream of and in the vicinity of the water-refrigerant heat exchanger 202. The inlet water temperature measuring unit 207 measures the temperature of the water or hot water flowing into the water-refrigerant heat exchanger 202.

[0041] An outlet heated water temperature measuring unit 208 is provided in the boiling pipe 108 downstream of and in the vicinity of the water-refrigerant heat exchanger 202. The outlet heated water temperature measuring unit 208 measures the temperature of the water or hot water flowing out of the water-refrigerant heat exchanger 202.

[0042] A three-way valve 123 is provided in the boiling pipe 108 at a portion between the water-refrigerant heat exchanger 202 and the first tank 101.

[0043] One outlet of the three-way valve 123 is connected to the top of the first tank 101, and the other outlet is connected to the bottom of the second tank 102. That is, the hot water that flows into the three-way valve 123 from the water-refrigerant heat exchanger 202 can be switched by the three-way valve 123 between flowing into the top of the first tank 101 and returning to the bottom of the second tank 102.

[0044] (Normal hot water operation) Figure 3 is a diagram illustrating the normal hot water discharge circuit during normal hot water discharge operation. The normal hot water discharge circuit is shown by the thick line in Figure 3.

[0045] The water inlet pipe 106 is a pipe for supplying water from the city water to the hot water storage unit 100, and branches into a tank water supply pipe 107, a hot water supply pipe 110, and a bath hot water supply pipe 111. A pressure reducing valve 121 is provided on the city water side and near the point where the water inlet pipe 106 branches.

[0046] The tank water supply pipe 107 is connected to the bottom of the second tank 102. The hot water supply pipe 110 is connected to a hot water supply terminal 302 such as a faucet or shower. The bath hot water supply pipe 111 is connected to a bathtub 301.

[0047] The hot water supply pipe 110 is provided with a hot water mixing valve 125, an outlet hot water temperature measuring unit 126, a hot water supply flow rate sensor 127, and a hot water supply flow rate adjustment valve 128 in this order from upstream to downstream.

[0048] The bath hot water supply pipe 111 is provided with a bath mixing valve 129, a bath hot water supply valve 130, a bath hot water supply temperature measuring unit 131, a bath flow rate sensor 132, and an after-heating temperature measuring unit 133 in that order from upstream to downstream.

[0049] A hot water mixing valve 125 provided in the hot water supply pipe 110 and a bath mixing valve 129 provided in the bath hot water supply pipe 111 are connected to the first tank 101 via a tank hot water outlet pipe 109. One end of the tank hot water outlet pipe 109 is connected to the first tank 101, and the other end branches into two paths, one of which is connected to the hot water mixing valve 125 and the other to the bath mixing valve 129.

[0050] During normal hot water operation, water supplied from city water to the water inlet pipe 106 is supplied to the bottom of the second tank 102 via the tank water supply pipe 107 branching off from the water inlet pipe 106. The cold or hot water in the second tank 102 is pumped from the top of the second tank 102 to the bottom of the first tank 101 via the connecting pipe 114.

[0051] At the same time, the hot water in first tank 101 is sent from the top of first tank 101 to tank outlet pipe 109 via intermediate mixing valve 124. The hot water in tank outlet pipe 109 and the water in water inlet pipe 106 are mixed in hot water supply mixing valve 125 or bath mixing valve 129 to become hot water of a predetermined temperature, which is sent to bathtub 301 or hot water supply terminal 302.

[0052] (Intermediate hot water discharge operation) FIG. 4 is a diagram illustrating the intermediate hot water discharge circuit during intermediate hot water discharge operation.

[0053] In Figure 4, the thick line indicates the intermediate hot water outlet circuit.

[0054] During intermediate hot water discharge operation, the hot water flowing out from the top of the first tank 101 and the hot water flowing out from the hot water outlet 104 are mixed by the intermediate mixing valve 124 to dispense hot water. The control unit 304 determines the mixing ratio of the hot water flowing out from the top of the first tank 101 and the hot water flowing out from the hot water outlet 104 based on a table. Specifically, the control unit 304 selects the optimal mixing ratio from the table so that the mixed hot water has a temperature equal to or higher than the hot water outlet temperature desired by the user. According to this mixing ratio, the hot water flowing out from the top of the first tank 101 and the hot water flowing out from the hot water outlet 104 are mixed by the intermediate mixing valve 124 to dispense hot water.

[0055] The hot water mixed in the intermediate mixing valve 124 is sent to the tank hot water outlet pipe 109. Thereafter, the hot water is supplied to the hot water supply terminal 302 via the hot water supply pipe 110, and to the bathtub 301 via the bath hot water supply pipe 111, just as in normal hot water supply operation.

[0056] Switching between normal hot water discharge operation and intermediate hot water discharge operation is performed by, for example, control unit 304 (see FIG. 1) provided in bathroom remote control 303.

[0057] FIG. 5 is a flowchart showing the operation of switching between the normal hot water dispensing operation and the intermediate hot water dispensing operation.

[0058] Switching between normal hot water discharge operation and intermediate hot water discharge operation is determined by comparing the temperature of the hot water stored in first tank 101 with the upper and lower limit temperatures of the medium-temperature water. The upper and lower limit temperatures of the medium-temperature water are arbitrarily determined within a preset temperature range of the medium-temperature water. For example, if the temperature range of the medium-temperature water is preset to 20°C to 38°C, the upper limit temperature is set to 38°C and the lower limit temperature is set to 20°C.

[0059] As shown in FIG. 5, the control unit 304 determines whether or not there is a hot water dispensing command (S1).

[0060] If a hot water dispense command is received ("Yes" in S1), the control unit determines whether the temperature (third temperature) measured by the third temperature measurement unit 117 provided in the first tank is equal to or lower than the upper limit temperature (S2). If no hot water dispense command is received ("No" in S1), the control unit continues to wait for a hot water dispense command.

[0061] If the third temperature is not equal to or lower than the upper limit temperature ("No" in S2), normal hot water dispensing operation is performed (S4).

[0062] If the third temperature is equal to or lower than the upper limit temperature ("Yes" in S2), it is determined whether the third temperature is equal to or higher than the lower limit temperature (S3).

[0063] If the third temperature is not equal to or higher than the lower limit temperature ("No" in S3), normal hot water dispensing operation is performed (S4).

[0064] If the third temperature is equal to or higher than the lower limit temperature ("Yes" in S3), the intermediate hot water dispensing operation is performed (S6).

[0065] (Reheating operation) FIG. 6 is a diagram illustrating the reheating circuit during the reheating operation.

[0066] In Figure 6, the thick line indicates the booster heating circuit.

[0067] As shown in FIG. 6, during the reheating operation, the first tank 101, the heat exchanger 103, and the return port 105 are connected in a ring shape by a reheating pipe 112 to form a reheating circuit on the tank side.

[0068] In the heat pump hot water supply device according to the first embodiment, return port 105 functions as a return port during the reheating operation, that is, as a reheating return port.

[0069] A reheating pump 134 and a heat exchanger temperature measuring unit 135 are provided in the reheating pipe 112 in a portion between the heat exchanger 103 and the return port 105 .

[0070] The booster pump 134 pumps the hot water at the top of the first tank 101 through a heat exchanger. Send to 103.

[0071] The heat exchanger temperature measuring unit 135 measures the temperature of the hot water flowing out from the heat exchanger 103 .

[0072] In addition, a bathtub-side reheating circuit is formed by connecting bathtub 301 and heat exchanger 103 in a ring shape with bath hot water supply pipe 111 and bath heat exchange pipe 113. Bath heat exchange pipe 113 is connected to the bath hot water supply pipe 111 at a portion where bath flow rate sensor 132 is installed, so as to merge with bath hot water supply pipe 111.

[0073] A circulation pump 136, a water level sensor 137, and a bath temperature measuring unit 138 are provided upstream of the heat exchanger 103 in the bath heat exchange pipe 113.

[0074] The circulation pump 136 sends the hot water from the bathtub 301 to the heat exchanger 103 .

[0075] The bath temperature measuring unit 138 measures the temperature of the hot water flowing from the bath heat exchange pipe 113 into the heat exchanger 103 .

[0076] During the reheating operation, hot water circulates in the reheating circuit on the tank side in the order of first tank 101, heat exchanger 103, and return port 105. At the same time, hot water circulates in the reheating circuit on the bathtub side in the order of bathtub 301 and heat exchanger 103.

[0077] (Main part configuration) As shown in Fig. 1, the heat pump water heater according to the first embodiment has a return port 105 in the middle of the first tank 101. Therefore, the heat pump water heater according to the first embodiment has good year-round hot water supply and insulation efficiency.

[0078] As described above, the warm water in a tank is generally divided into three layers, from top to bottom: high temperature water (e.g., above 38°C and below 90°C), medium temperature water (e.g., above 20°C and below 38°C), and low temperature water (e.g., below 20°C). Therefore, the warm water in the second tank 102 is also divided into three layers: high temperature water, medium temperature water, and low temperature water.

[0079] High-temperature water is, for example, hot water that is heated by the water-refrigerant heat exchanger 202 during boiling operation and flows into the top of the first tank 101, or hot water that is sent from the top of the first tank 101 to the tank hot water outlet pipe 109 during normal hot water discharge operation. Low-temperature water is, for example, hot water at the bottom of the second tank 102 that is sent to the water-refrigerant heat exchanger 202 by the boiling pump 122 during boiling operation, or hot water that flows into the bottom of the second tank 102 or the hot water supply pipe 110 via the water inlet pipe 106 during hot water discharge operation. Medium-temperature water is hot water in a temperature range between high-temperature water and low-temperature water.

[0080] During boiling operation, the low-temperature water in the second tank 102 is used for boiling. This is because boiling low-temperature water has better year-round hot water supply and insulation efficiency than boiling high-temperature or medium-temperature water. For this reason, one end of a boiling pipe 108 that connects the second tank 102 and the water-refrigerant heat exchanger 202 of the heat pump unit 200 is connected to the bottom of the second tank 102, where the low-temperature water is distributed.

[0081] Furthermore, during boiling operation, water from the city water supply is supplied to the second tank 102 from the bottom of the second tank 102. Because the water from the city water is low in temperature, using it for boiling operation in addition to the low-temperature water in the second tank 102 provides better year-round hot water supply and insulation efficiency.

[0082] However, in conventional heat pump water heaters, return port 905 is provided at the bottom of second tank 102. Therefore, during the booster operation, the high-temperature water flowing out from the top of first tank 101 is heat exchanged in heat exchanger 103, the temperature drops, and the water becomes medium-temperature water, which then returns to the bottom of second tank 102.

[0083] In this way, when the medium-temperature water returns to the bottom of the second tank 102, if a boiling operation is performed after the booster operation, the medium-temperature water that has returned to the bottom of the second tank 102 will be used for the boiling operation.

[0084] That is, in the boost operation, the medium-temperature water that flows out of the heat exchanger 103 returns to the bottom of the second tank 102 through the return port 905. For example, if the boiling operation is performed immediately thereafter, the medium-temperature water that has returned to the bottom of the second tank 102 is sent to the water-refrigerant heat exchanger 202 via the boiling pipe 108 and is boiled. That is, the boiling operation is performed using the medium-temperature water.

[0085] As described above, when boiling operation is performed with medium-temperature water, the year-round hot water supply and insulation efficiency is lower than when boiling operation is performed with low-temperature water. Furthermore, when the return port 905 is provided at the bottom of the second tank 102, the medium-temperature water returned to the second tank 102 during the booster operation is used for boiling operation, resulting in lower year-round hot water supply and insulation efficiency.

[0086] On the other hand, in the heat pump water heater according to the first embodiment, return port 105 is connected to first tank 101. Therefore, the medium-temperature water used in the booster heating operation is not used in the boiling operation, and the year-round hot water supply and insulation efficiency is good.

[0087] In addition, the return port 105 is connected to the middle part of the first tank 101. Therefore, the medium-temperature water that flows into the middle part of the first tank 101 via the return port 105 during the booster heating operation can be used by being discharged from the outlet 104 during the intermediate hot water discharge operation.

[0088] The outlet 104 and the return port 105 are located at the same position and at approximately the same height on the circumference of the middle part of the cylindrical first tank 101. Specifically, the return port 105 is located directly above the outlet 104.

[0089] Therefore, it is possible to prevent the high temperature water and the medium temperature water from mixing by quickly using the returning medium temperature water for intermediate hot water supply and not leaving the medium temperature water in the first tank 101. Therefore, it is possible to reduce the amount of high temperature water used that is suitable for various hot water supplies.

[0090] The outlet 104 and the return port 105 may be located at approximately the same height in the middle of the first tank 101, and may be located adjacent to each other in the circumferential direction or at approximately opposite positions.

[0091] <Embodiment 2> A heat pump hot water supply device according to a second embodiment will be described.

[0092] Fig. 7 is an overall configuration diagram illustrating a heat pump water heater according to embodiment 2. As shown in Fig. 7, the heat pump water heater according to embodiment 2 differs from the heat pump water heater according to embodiment 1 in that return port 141 is provided in second tank 102.

[0093] The return port 141 is for returning the hot water that has flowed out from the heat exchanger 103 into the second tank 102, and functions as a re-heating return port during re-heating operation. The return port 141 is located above the fifth temperature measurement unit 119 in the middle part of the second tank 102, near the upper end of the middle part.

[0094] The heat pump water heater according to the second embodiment has the same configuration as the heat pump water heater according to the first embodiment except for return port 141, and therefore a description of the components other than return port 141 will be omitted. In Fig. 7, the same components as those in the heat pump water heater according to the first embodiment are denoted by the same reference numerals.

[0095] The heat pump water heater according to the second embodiment, like the heat pump water heater according to the first embodiment, is capable of boiling operation, normal hot water discharge operation, intermediate hot water discharge operation, and booster heating operation.

[0096] (Reheating operation) Fig. 8 is a diagram illustrating the reheating circuit during reheating operation. The thick line in Fig. 8 indicates the reheating circuit.

[0097] As shown in Figure 8, during booster operation, a tank-side booster circuit is formed in which the first tank 101, heat exchanger 103, return port 141, and second tank 102 are connected in a ring shape by a booster pipe 112 and a connecting pipe 114.

[0098] During the reheating operation, hot water circulates in the reheating circuit on the tank side in the order of first tank 101, heat exchanger 103, return port 141, and second tank 102. At the same time, hot water circulates in the reheating circuit on the bathtub side in the order of bathtub 301 and heat exchanger 103.

[0099] (Main part configuration) As shown in Fig. 7, the heat pump water heater according to the second embodiment has a return port 141 provided at the top of second tank 102. Therefore, during the booster heating operation, the medium-temperature water that flows out of heat exchanger 103 returns to the top of second tank 102. During the boiling operation, the low-temperature water at the bottom of second tank 102 is used, and the medium-temperature water that returns from heat exchanger 103 is not used, so the heat pump water heater according to the second embodiment has good year-round hot water supply and insulation efficiency.

[0100] Furthermore, in the heat pump water heater according to the second embodiment, return port 141 is connected to second tank 102. Therefore, during the reheating operation, the hot water stored in first tank 101 and second tank 102 can be circulated in the reheating circuit on the tank side and used.

[0101] In the heat pump hot water supply device according to the first embodiment, a return port 105 is provided in the middle of the first tank 101. Therefore, as shown in Fig. 6, during the reheating operation, a tank-side reheating circuit is formed in which the first tank 101, the heat exchanger 103, and the return port 105 are connected in a ring shape by a reheating pipe 112.

[0102] Therefore, in the heat pump water heater according to the first embodiment, during the reheating operation, the high-temperature water flowing out of the first tank 101 is converted into medium-temperature water by heat exchange in the heat exchanger 103 and returned to the first tank 101 via the return port 105. Therefore, the high-temperature water used during the reheating operation is limited to the high-temperature water stored in the first tank 101.

[0103] With this configuration, for example, if the reheating operation is performed for a long period of time, or if the reheating operation is performed even though there is not enough high-temperature water stored in first tank 101, there is a possibility that a small amount of high-temperature water will be stored in first tank 101. If this happens, there is a possibility that sufficient high-temperature water will not be secured when the normal hot water supply operation is performed thereafter, and hot water will not be able to be supplied to hot water supply terminal 302.

[0104] Furthermore, when the amount of high-temperature water stored in the first tank 101 becomes small, it becomes necessary to perform boiling operation to increase the amount of high-temperature water in the first tank 101. However, even if the amount of high-temperature water in the first tank 101 is small, high-temperature water may still be stored in the second tank 102, and if the high-temperature water in the second tank 102 cannot be used for the booster heating operation, the year-round hot water supply and insulation efficiency will be poor.

[0105] On the other hand, in the heat pump water heater according to the second embodiment, return port 141 is connected to second tank 102. Therefore, during the reheating operation, the hot water stored in first tank 101 and second tank 102 can be used by circulating it in the reheating circuit on the tank side.

[0106] That is, high-temperature water can be supplied from the second tank 102 to the first tank 101 via the connecting pipe 114 at the same time that high-temperature water flows out from the first tank 101 to the heat exchanger 103 during the booster heating operation.

[0107] In this case, even when the additional heating operation is performed, there is a high possibility that high-temperature water will be stored in the first tank 101, and it is possible to ensure sufficient high-temperature water when performing the normal hot water supply operation.

[0108] <Modification> Although the configuration of the present disclosure has been described above based on the embodiments, the present disclosure is not limited to the above embodiments. Furthermore, the numerical values ​​described in the above embodiments are merely preferred examples and are not intended to limit the present disclosure. Furthermore, the configuration of the heat pump hot water heater can be appropriately modified within the scope of the technical concept of the present disclosure.

[0109] (Modification of the first embodiment) The position where the return port 105 is provided is not limited to approximately the center in the vertical direction of the intermediate portion, but may be near the upper end or lower end of the intermediate portion, for example.

[0110] The position where the return port 105 is provided is not limited to a position above the tap outlet 104, and it may be provided below the tap outlet 104, for example.

[0111] The position where the return port 105 is provided is not limited to the middle part of the first tank 101, but may be, for example, the top or bottom of the first tank 101.

[0112] (Modification of the second embodiment) The position where the return port 141 is provided is not limited to near the upper end of the intermediate portion, but may be, for example, approximately in the center in the vertical direction or near the lower end of the intermediate portion.

[0113] The position where the return port 141 is provided is not limited to the middle part of the second tank 102, but may be, for example, the top part of the second tank 102.

[0114] (Modifications common to all embodiments) The first temperature measuring unit 115, the second temperature measuring unit 116, the third temperature measuring unit 117, and the fourth temperature measuring unit 118 do not necessarily have to be provided.

[0115] The fifth temperature measuring unit 119 and the feedwater temperature measuring unit 120 do not necessarily have to be provided. [Industrial Applicability]

[0116] INDUSTRIAL APPLICABILITY The present invention is applicable to a heat pump hot water heater that is capable of a booster heating operation in which heat is exchanged between the hot water in the tank and the hot water in the bathtub. [Explanation of symbols]

[0117] 100 Hot water storage unit 101 First Tank 102 Second Tank 103 Heat exchanger 104 Tap 105 Return port 106 Water Inlet 107 Tank water supply pipe 108 Boiling pipe 109 Tank outlet pipe 110 Hot water pipe 111 Bath water supply pipe 112 Reheating pipe 113 Bath heat exchange tube 114 Connecting pipe 115 1st temperature measurement section 116 Second temperature measurement section 117 Third temperature measurement section 118 4th temperature measurement section 119 5th temperature measurement section 120 Supply water temperature measurement section 121 Pressure reducing valve 122 Boiling Pump 123 Three-way valve 124 Intermediate mixing valve 125 Hot water mixing valve 126 Outlet water temperature measurement unit 127 Hot water flow sensor 128 Hot water flow control valve 129 Bath Mixing Valve 130 Bath water valve 131 Bath water temperature measurement unit 132 Bath flow sensor 133 Reheating temperature measurement unit 134 Reheating pump 135 Heat exchanger temperature measurement section 136 Circulation Pump 137 Water level sensor 138 Bath temperature measurement unit 139 Relief valve 140 drain plug 141 Return port 200 Heat Pump Unit 201 Compressor 202 Water refrigerant heat exchanger 203 Pressure Reducer 204 Evaporator 205 Fan 206 Heat pump pipe 207 Inlet water temperature measurement section 208 Outlet water temperature measurement unit 209 Outside air temperature measurement unit 301 Bathtub 302 Hot water terminal 303 Bathroom remote control 304 Control Unit 305 Kitchen Remote Control 306 Additional remote control 905 Return port

Claims

1. a heat pump unit having a compressor and a water-refrigerant heat exchanger; a hot water storage unit having a first tank with a hot water outlet provided in the middle for hot water to flow out, a second tank connected to the first tank by a connecting pipe, and a heat exchanger for exchanging heat between the hot water flowing out of the first tank and the hot water in the bathtub; A heat pump type hot water supply device characterized in that a return port is provided at any position in the first tank or at a position above the bottom of the second tank for returning hot water flowing out from the heat exchanger into the tank.

2. The return port is provided at the top or middle of the first tank or the second tank.

2. The heat pump hot water supply system according to claim 1.

3. The return port is provided at a position above the tapping port in the first tank.

2. The heat pump hot water supply system according to claim 1.

4. The return port is provided at the top of the second tank.

2. The heat pump hot water supply system according to claim 1.

5. Each of the first tank and the second tank is provided with a temperature measuring unit for measuring the temperature of the hot water in the tank.

2. The heat pump hot water supply device according to claim 1, wherein:

6. The first tank is provided with temperature measuring units at positions above and below the hot water outlet for measuring the temperature of the hot water in the tank.

2. The heat pump hot water supply device according to claim 1, wherein:

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