JP4158694B2 - Hot water storage type heat pump water heater - Google Patents

Description

  The present invention relates to a hot water storage type heat pump hot water supply device that boils hot water in a hot water storage tank by a heat pump circuit and stores the hot water in the hot water storage tank as high temperature water, and supplies hot water at a set temperature. In particular, the present invention relates to a structure in which medium temperature water can be taken out from the middle of a hot water tank.

  In a hot water storage type heat pump hot water supply device, for example, when the amount of heat of high temperature water in the hot water tank is used to heat or reheat the bath, medium temperature water with a reduced temperature remains in the hot water tank. If not taken out, it will be boiled twice and the energy consumption efficiency (hereinafter referred to as COP) of the heat pump circuit will deteriorate. In order to alleviate such problems, in recent years, there is a structure in which medium-temperature water can be taken out as shown in Patent Document 1.

  Taking out the warm water in the hot water tank has the effect of reducing the remaining hot water (65-30 ° C when the boiling temperature is 90 ° C) in the area where the COP of the heat pump circuit deteriorates when boiling in the middle of the night. It is desirable to take it out and use it. When the medium-temperature water is taken out ideally, the remaining hot water is separated at the upper part of the hot water tank into high temperature water of 65 ° C. or higher and the lower temperature is divided into low temperature water at the feed water temperature, and there is no residual hot water boiled twice.

FIG. 9A is a partial schematic view showing a hot water storage tank 16 and a hot water supply circuit in a state where high-temperature water is sufficiently present in a conventional hot water storage type heat pump water heater, and FIG. 9B is a medium temperature water mixing valve in that state. 7 is a time chart for explaining the operation of the (second mixing valve) 34. In the conventional hot water supply temperature control, the intermediate hot water mixing valve 34 is made to stand by in a state where it is in communication with the high temperature water discharge path (first hot water supply path) 12 side of the upper part of the hot water tank 16, and first hot water is supplied from the upper part of the hot water tank 16. Supply (for example, for 10 to 15 seconds) to stabilize the opening degree of the hot water supply mixing valve (first mixing valve) 27, and then from an intermediate hot water hot water outlet (second hot water outlet) 35 provided on the side of the hot water storage tank 16. The hot water at a predetermined temperature is supplied to the hot water supply mixing valve 27 by gradually mixing the warm water and adjusting the temperature gently.
JP 2003-240342 A

  However, in the above-described conventional method, the temperature of the hot water that can be taken out from the intermediate temperature hot water outlet 35 is not accurately known, and even if the hot water having a temperature equal to or higher than the hot water supply temperature can be taken out from the intermediate hot water outlet 35. If there is a boundary layer near the hot water outlet (second hot water outlet) 33, there is a risk that cold water will be discharged when passing through it, and in order to avoid this, supply from an intermediate hot water hot water outlet 35 as shown in FIG. Even when the temperature of the hot water to be supplied is sufficiently higher than the temperature supplied to the hot water supply mixing valve 27, first, the hot water in the upper part of the hot water storage tank 16 is discharged.

  As a result, even when it is not necessary to use the high-temperature water at the top of the hot water storage tank 16, the high-temperature water is discharged every time the hot water is supplied, and the amount taken out from the medium-temperature water discharge channel 35 that is originally taken out and used is increased. There is no problem.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a hot water storage type heat pump hot water supply apparatus that uses hot water during hot water supply by preferentially taking it out from an intermediate hot water outlet. is there.

The present invention, in order to achieve the above object, employing the technical means described below. That is, in the invention according to claims 1 to 3, the control means (37) sets a temperature higher by a predetermined temperature (Δt) than the hot water supply set temperature (ST) as the switching determination temperature (KT), and stores hot water during standby for hot water supply. When the temperature of the hot water that can be taken out from the second hot water outlet (33) detected by the temperature detecting means (36) is equal to or higher than the switching determination temperature (KT), the second mixing means (34) is moved to the second hot water outlet (35) side. While waiting as a communicated state, otherwise, the second mixing means (34) is waited as a state communicating with the first hot water outlet (12) side ,
When the hot water is discharged, the opening degree of the second mixing means (34) is controlled according to the temperature detected by the mixing temperature sensor (42) provided on the downstream side of the second mixing means (34) .

  In addition, Claim 1 thru | or Claim 3 differs in a premise structure. Conventionally, in consideration of the sameness and simplification of control, the first hot water passage always with high temperature water (so that cold water is not discharged even when the boundary layer is directly below the second hot water outlet (33) as the worst state) 12) It was controlled to stand by in a state where it communicated with the side. However, according to the described invention, if the temperature of the hot water that can be taken out from the second hot water outlet (33) is a hot water temperature that can be used for temperature adjustment to the hot water supply set temperature (ST), the second hot water outlet (35) side from the beginning. In this state, the second mixing means (34) is put on standby, and the amount taken out from the intermediate temperature hot water outlet (35) can be remarkably increased. Thus, the COP at the time of boiling is not deteriorated by preferentially using the medium temperature water in the hot water tank (16).

  Moreover, in invention of Claim 4, as one of the hot water storage temperature detection means (36), from the same horizontal height as the 2nd hot water outlet (33) in a hot water storage tank (16) to a slightly lower horizontal height. The hot water storage temperature detection means (36c) is provided in the range. Conventionally, since the hot water storage temperature detecting means (36) is not at the height of the second hot water outlet (33), the temperature of the hot water that can be taken out from the second hot water outlet (33) is not accurately known, and since hot water is not discharged, the hot water is discharged from the hot water. I was letting out hot water. However, according to the fourth aspect of the present invention, the temperature of the hot water that can be taken out from the second hot water outlet (33) can be accurately determined, and the medium hot water can be taken out to a point that hardly remains. It is possible to eliminate the remaining hot water that is boiled twice.

  In the invention according to claim 5, the control means (37) is characterized in that the switching determination temperature (KT) has a hysteresis characteristic. According to the fifth aspect of the present invention, if the second mixing means (34) is switched at only one point of the switching determination temperature (KT) at the time of waiting for hot water, there is a variation in the hot water storage temperature detecting means (36c). A state in which the first hot water path (12) side and the second hot water path (35) side are repeated occurs, but this can be prevented by providing the switching determination temperature (KT) with a hysteresis characteristic.

  In the invention described in claim 6, the hot water supply flow rate detecting means (41) for detecting the flow rate of hot water supplied from the first mixing means (27) is provided, and the hot water flow rate detecting means (41) detects the hot water flow during hot water supply. When the hot water supply flow rate to be reduced is below a predetermined value, the control means (37) switches the temperature of hot water that can be taken out from the second outlet (33) detected by the hot water storage temperature detection means (36) to the switching determination temperature (KT). In the above case, the second mixing means (34) is in communication with the second hot water outlet (35), and in other cases, the second mixing means (34) is in communication with the first hot water outlet (12). It is characterized by a state.

  This is because the feedback control becomes unstable when the hot water supply flow rate decreases. According to the invention described in claim 6, when the hot water supply flow rate decreases to a predetermined value or less during hot water supply, the hot water storage temperature detecting means ( The temperature adjustment can be stabilized by fixing the second mixing means (34) to the second hot water outlet (35) side or the first hot water outlet (12) side according to the temperature detected in 36). In addition, the code | symbol in the bracket | parenthesis of each said means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing an overall configuration of a hot water storage type heat pump hot water supply apparatus according to a first embodiment of the present invention, and a thick line part shows a water channel part related to hot water supply. 1 is a heat pump unit, 2 is a hot water storage tank (hot water tank) unit, 3 is a hot water mixing tap, 4 is a heating load terminal such as a floor heating panel.

  The heat pump unit 1 includes a compressor 5, a water refrigerant heat exchanger 6 as a condenser, a decompressor 7, a heat pump circuit 9 including an evaporator 8, and hot water supply water as a water refrigerant heat exchanger. 6 includes a heat pump circulation pump 10 that circulates to 6 and a heat pump control unit 11 that controls their operation. Further, carbon dioxide is used as a refrigerant in the heat pump circuit 9 to constitute a supercritical heat pump cycle. In addition, since carbon dioxide is used as the refrigerant, it is possible to boil low temperature water to a high temperature of about 90 ° C. without an electric heater.

  The water-refrigerant heat exchanger 6 employs a counter flow system in which the refrigerant and hot water supply water flow oppositely. In the supercritical heat pump cycle, the refrigerant is condensed in the supercritical state during heat exchange, so that the hot water can be efficiently heated to a high temperature, and the water refrigerant heat exchanger 6 inlet temperature of the hot water and the outlet temperature of the refrigerant The pressure reducer 7 or the compressor 5 is controlled so that the temperature difference is constant. For this reason, when the inlet temperature of the water-refrigerant heat exchanger 6 for hot-water supply water is a low temperature of about 5 to 20 ° C., the hot-water supply water can be heated in a very good state with a COP (energy consumption efficiency) of 3.0 or more. Is possible.

  The hot water storage tank unit 2 has a high temperature water hot water outlet (first hot water outlet) 13 connected to the high temperature water hot water outlet (first hot water outlet) 12 at the upper end, and a hot water storage having a water supply inlet 15 connected to the water supply path 14 at the lower end. A tank (hot water tank) 16 is provided. A heat pump outlet 17 and a heat pump return port 18 are provided at the lower part of the hot water storage tank 16, and hot water in the hot water storage tank 16 is provided by a heat pump circulation circuit 19 that communicates with the water / refrigerant heat exchanger 6 of the heat pump unit 1. Are connected so that they can be circulated. The hot water storage tank 16 has a capacity of about 370L.

  Reference numeral 20 denotes a heat exchanger for heating as a heating source for the warm floor panel 4. On the primary side, a hot water outlet 21 communicating with the upper part of the hot water tank 16 and an intermediate hot water return port 22 below the hot water tank 16 are used for heating. Hot water in the hot water storage tank 16 is connected to be circulated by a heating circulation circuit 24 provided with a circulation pump 23. The secondary side is provided with a secondary side circuit 25 connected to the floor warming panel 4 so as to be circulated, and a secondary side circulation pump 26.

  Next, reference numeral 27 denotes a hot water supply mixing valve (first mixing means) constituted by an electric mixing valve that mixes hot water from the hot water outlet 12 and low temperature water from the water supply 14. The mixing ratio is controlled so that the hot water temperature detected by the provided hot water temperature sensor 29 becomes the hot water supply set temperature ST set by the user using the remote controller 30. The remote controller 30 has a hot water supply temperature setting switch 31, which can arbitrarily set the hot water supply temperature in a range of 35 to 60 ° C. and has a heating switch 32 for starting heating.

  An intermediate hot water outlet 33 (second outlet) provided at an intermediate height position of the hot water storage tank 16 is an intermediate hot water mixing port provided between the hot water outlet 13 of the hot water outlet 12 and the hot water mixing valve 27. It is connected to the input side of the valve (second mixing means) 34 via a medium-temperature water hot water outlet (second hot water outlet) 35. The intermediate hot water outlet 33 and the intermediate hot water discharge passage 35 are used for discharging the intermediate warm water whose temperature has been lowered by exchanging heat with the secondary side in the heating heat exchanger 20 from the hot water storage tank 16. The mixing valve 34 is mixed with the high-temperature water flowing through the high-temperature water discharge channel 12 and supplied to the hot-water supply mixing valve 27.

  The intermediate hot water mixing valve 34 is an electric mixing valve or the like, and has a temperature higher by a predetermined temperature Δt than an arbitrary hot water supply set temperature ST set by the remote controller 30 according to the temperature detected by the mixing temperature sensor 42 provided downstream thereof. In this way, the mixing valve can be adjusted by adjusting the mixing ratio (mixing temperature) by controlling the opening degree by a hot water supply control unit (control means) 37 described later.

  A plurality of hot water storage temperature sensors 36 (36a to 36e) are arranged in the vertical direction of the hot water storage tank 16, and to what height these hot water storage temperature sensors 36 detect a predetermined temperature (for example, 80 ° C.) or more. Thus, the amount of hot water remaining in the hot water storage tank 16 is detected.

  As a feature of the present embodiment, as one of the hot water storage temperature sensors 36, as one of the hot water storage temperature sensors within the range from the same horizontal height as the intermediate temperature hot water outlet 33 in the tank 16 to a slightly lower horizontal height. A medium temperature water temperature sensor 36c is provided. The installation position is ideally right below the hot water outlet 33, but if it is on the lower side, the amount of hot water taken out can be reduced. Incidentally, if the hot water storage temperature sensor 36 located above the intermediate hot water outlet 33 is used, cold water is discharged to the hot water supply side when a boundary layer of hot water and low temperature water comes to the intermediate hot water outlet 33.

  A hot water supply control unit 37 includes a microcomputer that receives an input from a sensor in the hot water storage tank unit 2 and controls driving of the actuator. A remote controller 30 is connected to the hot water supply control unit 37 by wireless or wired so that the user can set an arbitrary hot water supply set temperature ST. Note that 38 is an overpressure prevention valve for preventing overpressure of the hot water storage tank 16, 39 is a water supply temperature sensor for detecting the temperature of the water supply, 40 is a pressure reducing valve for reducing the pressure of the water supply, and 41 is a flow rate of hot water for supplying hot water. This is a flow rate counter (hot water flow rate detection means).

  Next, an outline of operation in this embodiment will be described. First, the boiling operation will be described. When the hot water storage temperature sensor 36 detects that the required amount of hot water does not remain in the hot water storage tank 16 in the hot water storage tank 16 in the midnight power time zone, the hot water supply control unit 37 issues a boiling start command to the heat pump control unit 11. Upon receiving the command, the heat pump controller 11 drives the heat pump circulation pump 10 after starting the compressor 5, and water-refrigerant heat exchange is performed for low-temperature water of about 5 to 20 ° C. taken out from the heat pump outlet 17 below the hot water storage tank 16. It is heated to a high temperature of about 90 ° C. by the vessel 6 and returned to the hot water storage tank 16 through the heat pump circulation circuit 19 from the heat pump return port 18 above the hot water storage tank 16.

  Thereby, hot water is sequentially stacked from the upper part of the hot water storage tank 16 and stored. When the hot water storage temperature sensor 36 detects that the necessary amount of hot water has been stored, the hot water supply control unit 37 issues a boiling stop command to the heat pump control unit 11, and the heat pump control unit 11 stops the compressor 5 and heat pump circulation pump. 10 is also stopped and the boiling operation is finished.

  Next, the heating operation will be described. When the heating switch 32 of the remote controller 30 is turned on, the hot water supply control unit 37 drives the heating circulation pump 23 and the secondary circulation pump 26 to supply hot water of about 70 to 90 ° C. taken out from the high temperature water outlet 21. The medium-temperature water, which has flowed into the heating heat exchanger 20 and exchanged heat with the warm water in the secondary circuit 25 and has been reduced to about 30 to 50 ° C. by heat exchange, returns from the medium-temperature water return port 22 to the lower part of the hot water storage tank 16.

  Thereby, the hot water is stored so as to push up the boundary surface of the hot water and the intermediate hot water in the form of replacing the hot water. On the secondary side, hot water heated by the heating heat exchanger 20 flows into the floor heating panel 4, heats the space to be heated, and circulates again to the heating heat exchanger 20. When the heating switch 32 of the remote controller 30 is turned off, the hot water supply control unit 37 stops the heating circulation pump 23 and the secondary-side circulation pump 26 and ends the heating operation.

  Next, an outline of the hot water supply operation will be described. When the hot-water supply faucet 3 is opened, high-temperature water and medium-temperature water in the hot water storage tank 16 are pushed out by the supply water pressure from the water supply passage 14. The hot water is pushed out from the hot water outlet 13 at the upper end, and the intermediate hot water is pushed out from the intermediate hot water outlet 33. The extruded high-temperature water of about 70 to 90 ° C. and medium-temperature water of about 30 to 50 ° C. flow into the intermediate-temperature water mixing valve 34 through the high-temperature water hot water outlet 12 and the intermediate hot water hot-water outlet 35, respectively. The hot water is mixed with hot water having a temperature higher by a predetermined temperature than the hot water supply set temperature ST set in.

  The mixed hot water flows into the hot water supply mixing valve 27 and is mixed with low temperature water of about 5 to 20 ° C. from the water supply passage 14, adjusted to the hot water supply set temperature ST, and hot water is supplied from the hot water mixing tap 3. In this way, the mixing ratio is adjusted so that the intermediate temperature water mixing valve 34 is an electric mixing valve, and the mixing ratio is adjusted to be a predetermined temperature higher than an arbitrary hot water supply set temperature ST set by the remote controller 30. It can be used according to any hot water set temperature ST.

  For example, if an arbitrary hot water supply set temperature ST is 50 ° C., the mixing temperature of the intermediate hot water mixing valve 34 is set to 55 ° C., which is approximately 5 ° C. higher than 50 ° C., and hot water mixed at 55 ° C. Hot water is supplied by adjusting the temperature ST to 50 ° C. If the arbitrary hot water supply set temperature ST is the initial set value of 42 ° C., the mixing temperature of the intermediate hot water mixing valve 34 is set to 47 ° C., which is approximately 5 ° C. higher than 42 ° C., and the hot water mixed at 47 ° C. Then, hot water is supplied by adjusting to an arbitrary hot water supply set temperature ST of 42 ° C. In this way, hot water can be supplied using medium-temperature water according to an arbitrary hot water set temperature ST at that time.

  At this time, the intermediate hot water return port 22 is provided in the hot water storage tank 16 at a position higher than the water supply port 15 at the lowermost end of the hot water storage tank 16 and the lower heat pump outlet port 17, so that the intermediate hot water returns from the intermediate hot water return port 22 by heating operation. Even if the hot water is returned to the lower part of the hot water storage tank 16, low temperature water from the hot water supply tank 14 flows from the lower end of the hot water storage tank 16 by using hot water, so that low temperature water is secured at the lowermost end of the hot water storage tank 16. In the next boiling, the water is always boiled from low temperature water. Further, the high temperature water outlet 21 is provided in the middle of the high temperature water outlet 12 connected to the hot water outlet 13 so as to reduce the opening of the hot water storage tank 16.

  Further, since the intermediate hot water outlet 33 is provided at a position higher than the intermediate warm water return port 22, a certain amount of capacity can be secured between the intermediate warm water return port 22 and the intermediate warm water outlet 33, and heat exchange for heating is performed. The medium-temperature water whose temperature has been lowered by the vessel 20 can be temporarily stored by the amount, and the amount of medium-temperature water that is stored at a position higher than the medium-temperature water tap 33 can be reduced.

  Specifically, since the intermediate temperature hot water outlet 33 is at an intermediate height position of the hot water storage tank 16, a capacity of about 90 to 120 L can be secured between the intermediate temperature water return port 22 and the intermediate temperature hot water outlet 33, The medium-temperature water whose temperature has been lowered by the heat exchanger 20 for heating can be temporarily stored by that amount, and the amount of medium-temperature water that is stored at a position higher than the medium-temperature water outlet 33 can be reduced. it can. That is, it is possible to reduce the amount of medium-temperature water that cannot be taken out from the medium-temperature water outlet 33 as much as possible.

  In the present embodiment, the intermediate hot water outlet 33 is provided at a position higher than the intermediate warm water return port 22 as described above. Therefore, the capacity or time from the generation of intermediate warm water to its use by the capacity corresponding to the difference in height. Even if the hot water is supplied at a time interval after the intermediate warm water is generated for a certain volume, the intermediate hot water can be used for hot water supply.

  In this way, since the hot water used as a heating heat source during hot water supply is taken out from the hot water storage tank 16 in preference to the hot water, hot water is supplied until the hot water can be fully supplied. When there is no problem, the hot water in the hot water storage tank 16 decreases every time hot water is supplied, and is replaced with low-temperature water from the water supply channel 14, and when the boiling operation is performed at midnight, the temperature of the hot water is not low. Low low-temperature water is boiled by the heat pump circuit 9, and the efficiency of boiling is improved, and the COP as the heat pump hot water supply apparatus is improved.

  Further, the intermediate hot water mixing valve 34 is mixed with hot water having a temperature approximately 5 ° C. higher than the hot water supply set temperature ST adjusted by the hot water supply mixing valve 27, and then mixed with the hot water supply set temperature ST at the hot water supply mixing valve 27 to supply hot water. Thus, hot water having an arbitrary hot water supply set temperature ST set by the remote controller 30 can be reliably supplied without any special operation on the user side.

  Next, the control part according to the present invention will be described. FIG. 2 is a flowchart showing the concept during standby in the present invention. The hot water supply control unit 37 sets a temperature higher than the hot water supply set temperature ST by a predetermined temperature Δt (10 ° C. in the present embodiment) as the switching determination temperature KT. The reason for setting the predetermined temperature Δt is a margin for preventing the water region from being near the intermediate temperature hot water outlet 33. During hot water supply standby, first, in step S1, it is determined whether or not the temperature of the hot water that can be taken out from the intermediate hot water outlet 33 detected by the intermediate hot water temperature sensor 36c is equal to or higher than the switching determination temperature KT.

  When the determination result is YES and the temperature of the hot water that can be taken out from the intermediate temperature hot water outlet 33 is equal to or higher than the switching determination temperature KT, the process proceeds to step S2 and the intermediate temperature water mixing valve 34 is communicated with the intermediate temperature water discharge channel 35 side. Waiting as a state. Further, when the determination result in step S1 is NO and the temperature of the hot water that can be taken out from the intermediate temperature hot water outlet 33 is lower than the switching determination temperature KT, the process proceeds to step S3 and the intermediate temperature water mixing valve 34 is set to the high temperature water outlet. It is made to stand by as the state connected to 12 side.

  FIG. 3 is a graph showing an example of hysteresis characteristics of the switching determination temperature KT. In the actual machine, the hot water supply controller 37 gives the switching determination temperature KT hysteresis characteristics as shown in FIG. For example, when the switching determination temperature KT is 50 ° C., when the temperature detected by the intermediate temperature water temperature sensor 36c is 53 ° C. or more of the switching determination temperature KT + 3 ° C., the switching is performed to the intermediate temperature water discharge channel 35 side, and conversely, the switching determination temperature KT-2. When it becomes 48 degrees C or less, it switches to the high-temperature water tapping channel 12 side.

  Next, an example of operation in different states will be described with reference to FIGS. 4A is a partial schematic view of the hot water storage tank 16 and the hot water supply circuit in a state where there is sufficient high-temperature water at the intermediate temperature hot water outlet 33, and FIG. 4B is a partial schematic view of the intermediate temperature water mixing valve 34 in that state. It is a time chart explaining operation | movement. The temperature of the hot water taken out from the intermediate hot water outlet 33 can be detected by an intermediate hot water temperature sensor 36c provided at the same height as the intermediate hot water outlet 33. In this example, the temperature is adjusted to 50 ° C. from the hot water supply mixing valve 25 and discharged, while 80 ° C. is detected by the medium hot water temperature sensor 36c. Thus, in the situation where there is sufficient high-temperature water at the intermediate temperature hot water outlet 33, the hot water is taken out only from the intermediate temperature hot water outlet 33, and the high temperature water above the hot water storage tank 16 is not used.

  (A) of FIG. 5 is a partial schematic view showing the hot water storage tank 16 and the hot water supply circuit in a situation where hot water having a temperature equal to or lower than the hot water supply set temperature ST is present immediately below the intermediate temperature hot water outlet 33, and (b) is a schematic view of 4 is a time chart for explaining the operation of a hot water mixing valve 34; In the case of this example, the hot water outlet 33 still has hot water of the switching determination temperature KT or higher, and the hot water mixing valve 34 is waiting on the hot water outlet 35 side so that the hot water can be taken out immediately. When the hot water is discharged, feedback control is performed according to the temperature detected by the medium hot water temperature sensor 36c.

  When the temperature of the intermediate temperature hot water outlet 33 is lower than the hot water supply set temperature ST + 5 ° C., the temperature of the intermediate hot water mixed with the hot water in the upper part of the hot water storage tank 16 and supplied to the hot water supply mixing valve 27 is controlled at the hot water supply set temperature ST + 5 ° C. As a result, the hot water in the upper part of the hot water storage tank 16 is utilized only when high temperature water is required, so that hot water below the intermediate hot water outlet 33 can be taken out as much as possible.

  FIG. 6A is a partial schematic view showing the hot water storage tank 16 and the hot water supply circuit in a situation where there is no hot water having a sufficient temperature at the intermediate temperature hot water outlet 33, and FIG. It is a time chart explaining operation | movement of. In the case of FIG. 6, since there is no hot water at a temperature to be supplied to the hot water mixing valve 27 below the intermediate hot water outlet 33, the temperature of the intermediate hot water outlet 33 is monitored in advance and the intermediate hot water mixing valve 34 is hot. The hot water supply is started by waiting on the side of the water supply hot water path 12. In the case of this example, there is a possibility that there is water in the vicinity of the intermediate temperature hot water outlet 33, and hot water in the upper part of the hot water storage tank 16 is allowed to flow for a while (for example, 10 to 15 seconds), and the opening degree of the hot water supply mixing valve 27 is stabilized. After that, the temperature will be adjusted gradually.

  Next, FIG. 7 is a flowchart showing the concept of hot water supply in the present invention. First, a flow rate counter 41 is provided as a hot water supply flow rate detecting means for detecting the hot water flow rate of hot water supplied from the hot water supply mixing valve 27. In step S11, it is determined whether or not the hot water flow rate detected by the flow rate counter 41 during hot water supply is a predetermined value or less (for example, 1 L / min or less).

If the determination result is NO and the hot water supply flow rate is equal to or greater than a predetermined value, the determination in step S11 is repeated. If the determination result in step S11 is YES and the hot water supply flow rate is equal to or less than the predetermined value, the process proceeds to step S12, and the hot water taken out from the intermediate hot water outlet 33 detected by the intermediate hot water temperature sensor 36c as in the standby state. It is determined whether or not the temperature is equal to or higher than the switching determination temperature KT.
When the determination result is YES and the temperature of the hot water taken out from the intermediate temperature hot water outlet 33 is equal to or higher than the switching determination temperature KT, the process proceeds to step S13, and the intermediate temperature water mixing valve 34 is connected to the intermediate temperature water outlet 35 side. Fix in state. If the determination result in step S12 is NO and the temperature of the hot water taken out from the intermediate temperature hot water outlet 33 is lower than the switching determination temperature KT, the process proceeds to step S14 and the intermediate temperature water mixing valve 34 is set to the high temperature water outlet. It fixes in the state connected to 12 side.

  Next, features in the present embodiment will be described. First, the hot water supply control unit 37 switches a temperature that is higher than the hot water supply set temperature ST by a predetermined temperature Δt as the switching determination temperature KT, and switches the temperature of hot water that can be taken out from the intermediate hot water outlet 33 detected by the hot water storage temperature detection sensor 36 during standby for hot water supply. When the temperature is equal to or higher than the determination temperature KT, the intermediate warm water mixing valve 34 is set in a standby state in communication with the intermediate hot water discharge channel 35 side, and in other cases, the intermediate warm water mixing valve 34 is set in a standby state in communication with the high temperature water discharge channel 12 side. I try to let them.

  Conventionally, considering the sameness and simplification of the control, as a worst-case condition, even when the boundary layer is directly below the intermediate temperature hot water outlet 33, the hot water outlet 12 where the high temperature water always flows is provided so as not to discharge cold water. It was controlled to wait in a connected state. However, according to this, if the temperature of the hot water that can be taken out from the intermediate temperature hot water outlet 33 is a hot water temperature that can be used for temperature adjustment to the hot water supply set temperature ST, the intermediate temperature water mixing valve is in communication with the intermediate temperature water discharge channel 35 from the beginning. 34 is made to stand by, and the taking-out amount from the intermediate temperature hot water discharge channel 35 can be increased remarkably. Thus, the COP at the time of boiling is not deteriorated by preferentially using the medium temperature water in the hot water storage tank 16.

  As one of the hot water storage temperature sensors 36, an intermediate hot water temperature sensor 36c is provided in the range from the same horizontal height as the intermediate hot water outlet 33 in the hot water storage tank 16 to a slightly lower horizontal height. Conventionally, since the hot water storage temperature sensor 36 is not at the height of the intermediate temperature hot water outlet 33, the temperature of the hot water that can be taken out from the intermediate temperature hot water outlet 33 is not accurately known, and the hot water is discharged from the high temperature water so as not to discharge cold water. However, according to this, the temperature of the hot water that can be taken out from the intermediate hot water outlet 33 can be accurately determined, and the intermediate hot water can be taken out to a point where almost no hot water remains. It can be lost.

  Moreover, the hot water supply control unit 37 gives the switching determination temperature KT hysteresis characteristics. According to this, when the hot / cold water mixing valve 34 is switched at only one point of the switching determination temperature KT during the hot water standby, the hot water hot water discharge channel 12 side and the intermediate hot water hot water flow channel 35 side are connected due to variations in the hot water storage temperature sensor 36c. Although a repeated state occurs, this can be prevented by providing the switching determination temperature KT with a hysteresis characteristic.

  Moreover, while providing the flow rate counter 41 which detects the hot-water supply flow rate supplied from the hot-water supply mixing valve 27, and the hot-water supply flow rate detected by the flow rate counter 41 during the hot-water supply becomes a predetermined value or less, the hot-water supply control unit 37 When the temperature of the hot water that can be taken out from the intermediate temperature hot water outlet 33 detected by the hot water temperature sensor 36c is equal to or higher than the switching determination temperature KT, the intermediate temperature water mixing valve 34 is in communication with the intermediate temperature water outlet 35 side, otherwise The intermediate temperature water mixing valve 34 is in communication with the high temperature water tap line 12 side.

  This is because the feedback control becomes unstable when the hot water supply flow rate decreases. According to this, when the hot water supply flow rate decreases to a predetermined value or less during hot water supply, it depends on the temperature detected by the medium hot water temperature sensor 36c. Thus, the temperature adjustment can be stabilized by fixing the intermediate warm water mixing valve 34 to the intermediate warm water discharge channel 35 side or the high temperature water discharge channel 12 side.

  In addition, in a normal hot water storage type heat pump water heater, hot water of 75 ° C. or less is boiled again. However, in the hot water storage type heat pump water heater of this embodiment, it can be used even in medium temperature water, so that only hot water of 60 ° C. or lower is boiled up again. In this way, the boiling load is reduced.

(Second Embodiment)
FIG. 8 is a schematic diagram showing an overall schematic configuration of a hot water storage type heat pump hot water supply apparatus in a second embodiment of the present invention. In the first embodiment described above, the amount of heat of the hot water taken out from the hot water outlet 21 provided at the upper part of the hot water tank 16 is used for floor heating, and the medium hot water whose temperature has been lowered is returned to the hot water tank 16 at the lower part of the hot water tank 16. Although the heat utilization circulation circuit 24 returning to the port 22 is provided, in the present embodiment, a serpentine tube 43 as a heat exchanging means is disposed inside the hot water storage tank 16 and circulated through the inner side of the serpentine tube 43 with hot water inside the hot water storage tank 16 The heat utilization circulation circuit 24 is configured such that the fluid to be heated is heated and the amount of heat obtained by the fluid is used outside. Specifically, bath water is circulated through the serpentine tube 43 and used for chasing and keeping warm. The present invention is also effective in the hot water storage type heat pump water heater having such a configuration.

(Other embodiments)
In the above-described embodiment, the heat utilization circulation circuit 24 is used for heating or heating of bath water, but the heat utilization method and configuration are not limited, and a hot water storage type heat pump water heater without the heat utilization circulation circuit 24 is used. It may be.

It is a schematic diagram which shows the whole structure of the hot water storage type heat pump hot-water supply apparatus in 1st Embodiment of this invention. It is a flowchart which shows the view at the time of standby in this invention. It is a graph which shows the hysteresis characteristic example of switching determination temperature. (A) is the partial schematic diagram of the hot water storage tank 16 and hot water supply circuit of the condition where high temperature water fully exists in the intermediate temperature hot water outlet 33, (b) demonstrates the action | operation of the intermediate temperature water mixing valve 34 in the condition. It is a time chart. (A) is the partial schematic diagram which shows the hot water storage tank 16 and the hot water supply circuit of the condition where the hot water below the hot water supply preset temperature ST exists just under the intermediate temperature hot water outlet 33, (b) is the intermediate temperature water mixing valve in the condition 34 is a time chart for explaining the operation of 34. (A) is the partial schematic diagram which shows the hot water storage tank 16 and the hot water supply circuit of the condition where hot water of sufficient temperature does not exist in the intermediate temperature hot water outlet 33, (b) is the operation of the intermediate temperature water mixing valve 34 in that condition. It is a time chart to explain. It is a flowchart which shows the view at the time of the hot water supply in this invention. It is a schematic diagram which shows the whole schematic structure of the hot water storage type heat pump hot-water supply apparatus in 2nd Embodiment of this invention. (A) is the partial schematic diagram which shows the hot water storage tank 16 and the hot water supply circuit of the condition where sufficient high temperature water exists in the conventional hot water storage type heat pump hot water supply apparatus, (b) is the operation | movement of the intermediate temperature water mixing valve 34 in the condition It is a time chart explaining.

Explanation of symbols

5 ... Compressor
6. Water refrigerant heat exchanger (condenser)
8 ... Evaporator 9 ... Heat pump circuit 12 ... High temperature water tap (first tap)
13 ... Hot water outlet (first outlet)
14 ... Water supply channel 15 ... Water supply port 16 ... Hot water storage tank (hot water storage tank)
DESCRIPTION OF SYMBOLS 17 ... Heat pump outlet 18 ... Heat pump return port 19 ... Heat pump circulation circuit 21 ... High temperature water outlet 22 ... Medium temperature water return port 24 ... Heat utilization circulation circuit 27 ... Hot water supply mixing valve (1st mixing means)
33 ... Medium hot water outlet (second outlet)
34. Medium warm water mixing valve (second mixing means)
35 ... Medium hot water hot spring (second hot spring)
36 ... Hot water storage temperature sensor (hot water storage temperature detection means)
36c ... Medium hot water temperature sensor (hot water storage temperature detection means)
37 ... Hot water supply control unit (control means)
41 ... Flow rate counter (hot water flow rate detection means)
43 ... Snake tube (heat exchange means)
KT ... Switching determination temperature ST ... Hot water supply set temperature Δt ... Predetermined temperature

Claims (6)

A first hot water outlet (13) which has a water supply port (15) into which low-temperature water supplied from the water supply channel (14) flows in at the lower end and discharges hot water stored in the hot water from the first hot water path (12). A hot water tank (16) at the upper end,
A heat pump circuit (9) having a compressor (5), a condenser (6), an evaporator (8);
The low temperature water taken out from the heat pump outlet (17) provided in the lower part of the hot water tank (16) is heated by the condenser (6), and the heated high temperature water is provided in the upper part of the hot water tank (16). A heat pump circuit (19) for returning from (18) into the hot water tank (16);
A second hot water outlet (33) provided at a position lower than the first hot water outlet (13) and allowing the hot water in the hot water storage tank (16) to flow out of the second hot water outlet (35);
Hot water storage temperature detection means (36) capable of detecting the temperature of hot water that can be taken out from the second outlet (33);
High temperature water flowing out from the first hot water outlet (13) and hot water flowing out from the second hot water outlet (33) are mixed to adjust to a temperature higher than a preset hot water supply temperature by a predetermined temperature (34). )When,
First mixing means (27) for mixing hot water flowing out from the second mixing means (34) and low-temperature water supplied from the water supply channel (14) to adjust the hot water supply set temperature;
A hot water storage type hot water supply apparatus comprising a control means (37) for controlling these operations,
The control means (37) sets a temperature that is higher than the hot water supply set temperature (ST) by a predetermined temperature (Δt) as a switching determination temperature (KT), and is detected by the hot water storage temperature detection means (36) during hot water supply standby. When the temperature of the hot water that can be taken out from the hot water outlet (33) is equal to or higher than the switching determination temperature (KT), the second mixing means (34) is made to stand by as being in communication with the second hot water outlet (35) side, and otherwise In this case, the second mixing means (34) is put on standby as a state communicating with the first hot water outlet (12) side ,
When the hot water is discharged, the opening degree of the second mixing means (34) is controlled according to the temperature detected by the mixing temperature sensor (42) provided on the downstream side of the second mixing means (34). Hot water storage type heat pump water heater. A first hot water outlet (13) which has a water supply port (15) into which low-temperature water supplied from the water supply channel (14) flows in at the lower end and discharges hot water stored in the hot water from the first hot water path (12). A hot water tank (16) at the upper end,
A heat pump circuit (9) having a compressor (5), a condenser (6), an evaporator (8);
The low temperature water taken out from the heat pump outlet (17) provided in the lower part of the hot water tank (16) is heated by the condenser (6), and the heated high temperature water is provided in the upper part of the hot water tank (16). A heat pump circuit (19) for returning from (18) into the hot water tank (16);
While using the amount of heat of the high-temperature water taken out from the high-temperature water outlet (21) provided at the upper part of the hot water storage tank (16), the medium-temperature water return port provided at the lower part of the hot water storage tank (16) is used for the medium-temperature water return port ( 22) a heat utilization circulation circuit (24) to be returned to
A second outlet which is provided at a position higher than the intermediate hot water return port (22) and lower than the first hot water outlet (13) and causes the hot water in the hot water storage tank (16) to flow out from the second hot water outlet (35). With a gate (33),
Hot water storage temperature detection means (36) capable of detecting the temperature of hot water that can be taken out from the second outlet (33);
High temperature water flowing out from the first hot water outlet (13) and hot water flowing out from the second hot water outlet (33) are mixed to adjust to a temperature higher than a preset hot water supply temperature by a predetermined temperature (34). )When,
First mixing means (27) for mixing hot water flowing out from the second mixing means (34) and low-temperature water supplied from the water supply channel (14) to adjust the hot water supply set temperature;
A hot water storage type hot water supply apparatus comprising a control means (37) for controlling these operations,
The control means (37) sets a temperature that is higher than the hot water supply set temperature (ST) by a predetermined temperature (Δt) as a switching determination temperature (KT), and is detected by the hot water storage temperature detection means (36) during hot water supply standby. When the temperature of the hot water that can be taken out from the hot water outlet (33) is equal to or higher than the switching determination temperature (KT), the second mixing means (34) is made to stand by in a state of communicating with the second hot water outlet (35) side, and otherwise In this case, the second mixing means (34) is kept in a standby state as being in communication with the first hot water outlet (12) side ,
When the hot water is discharged, the opening degree of the second mixing means (34) is controlled according to the temperature detected by the mixing temperature sensor (42) provided on the downstream side of the second mixing means (34). Hot water storage type heat pump water heater. A first hot water outlet (13) which has a water supply port (15) into which low-temperature water supplied from the water supply channel (14) flows in at the lower end and discharges hot water stored in the hot water from the first hot water path (12). A hot water tank (16) at the upper end,
A heat pump circuit (9) having a compressor (5), a condenser (6), an evaporator (8);
The low temperature water taken out from the heat pump outlet (17) provided in the lower part of the hot water tank (16) is heated by the condenser (6), and the heated high temperature water is provided in the upper part of the hot water tank (16). A heat pump circuit (19) for returning from (18) into the hot water tank (16);
The heat exchange means (43) is disposed inside the hot water tank (16), and the fluid flowing through the heat exchange means (43) is heated with hot water inside the hot water tank (16) to obtain the fluid. A heat-use circulation circuit (24) that uses heat outside,
A second hot water outlet (33) provided at a position lower than the first hot water outlet (13) and allowing the hot water in the hot water storage tank (16) to flow out of the second hot water outlet (35);
Hot water storage temperature detection means (36) capable of detecting the temperature of hot water that can be taken out from the second outlet (33);
High temperature water flowing out from the first hot water outlet (13) and hot water flowing out from the second hot water outlet (33) are mixed to adjust to a temperature higher than a preset hot water supply temperature by a predetermined temperature (34). )When,
First mixing means (27) for mixing hot water flowing out from the second mixing means (34) and low-temperature water supplied from the water supply channel (14) to adjust the hot water supply set temperature;
A hot water storage type hot water supply apparatus comprising a control means (37) for controlling these operations,
The control means (37) sets a temperature that is higher than the hot water supply set temperature (ST) by a predetermined temperature (Δt) as a switching determination temperature (KT), and is detected by the hot water storage temperature detection means (36) during hot water supply standby. When the temperature of the hot water that can be taken out from the hot water outlet (33) is equal to or higher than the switching determination temperature (KT), the second mixing means (34) is made to stand by as being in communication with the second hot water outlet (35) side, and otherwise In this case, the second mixing means (34) is put on standby as a state communicating with the first hot water outlet (12) side ,
When the hot water is discharged, the opening degree of the second mixing means (34) is controlled according to the temperature detected by the mixing temperature sensor (42) provided on the downstream side of the second mixing means (34). Hot water storage type heat pump water heater.   As one of the hot water storage temperature detection means (36), the hot water storage temperature detection means (within the range from the same horizontal height as the second hot water outlet (33) in the hot water storage tank (16) to a slightly lower horizontal height) ( The hot water storage type heat pump hot water supply apparatus according to any one of claims 1 to 3, wherein 36c) is provided.   The hot water storage type heat pump hot water supply apparatus according to any one of claims 1 to 3, wherein the control means (37) has a hysteresis characteristic in the switching determination temperature (KT).   A hot water flow rate detecting means (41) for detecting the hot water flow rate for supplying hot water from the first mixing means (27) is provided, and the hot water flow rate detected by the hot water flow rate detecting means (41) during hot water supply is less than a predetermined value. If the temperature of the hot water that can be taken out from the second outlet (33) detected by the hot water storage temperature detection means (36) is equal to or higher than the switching determination temperature (KT), the control means (37) A state in which the second mixing means (34) is in communication with the second hot water outlet (35) side, and in other cases, the second mixing means (34) is in communication with the first hot water outlet (12) side. The hot water storage type heat pump hot-water supply apparatus according to any one of claims 1 to 3, wherein

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