JP6604166B2 - Hot water storage water heater - Google Patents

Description

  The present invention relates to a hot water storage type hot water supply apparatus such as a heat pump hot water supply apparatus.

  In the heat pump hot water supply device, hot water heated by using a heat pump flows into the hot water storage tank and is stored therein, and the stored hot water is supplied via a hot water pipe connected to the hot water storage tank. It is usual that hot water can be delivered to the hot water supply destination. In such a heat pump hot-water supply apparatus, it is controlled so that hot water of a necessary heat amount is previously boiled and stored in a hot water storage tank according to a heat demand predicted in the future. In order to perform such control accurately, it may be necessary to determine whether or not the inside of the hot water storage tank is full of heat storage. Therefore, conventionally, a plurality of temperature sensors are provided so as to be arranged at intervals in the vertical direction of the hot water tank, and the hot water tank is filled with heat based on the hot water temperature detected by the multiple temperature sensors. A means for determining whether or not there is is employed.

  However, the prior art has room for improvement as described below.

  That is, the high-temperature hot water heated by the heat pump is sequentially stored from the upper side to the lower side in the hot water storage tank. For this reason, even when it is determined that the temperature of hot water is detected by all of the plurality of temperature sensors attached to the hot water storage tank and it is determined that the heat storage is full, the temperature sensor is actually lower than the lowest temperature sensor. In the lower region below, there may be medium / low temperature hot water. Such medium and low temperature hot water is often lower than the hot water supply set temperature and cannot be used for hot water supply as it is. For this reason, it is desired to appropriately eliminate such a state.

  As a means for meeting such a demand, there is a means described in Patent Document 1. In the means described in the document, the hot and cold water present in the lower part of the hot water tank is fed into the hot hot water region in the upper part of the hot water tank, thereby mixing the hot water and the hot water in the hot water tank. Make sure there is no medium or low temperature water. However, according to such a means, the temperature stratification of the high temperature hot water formed in the upper part in the hot water storage tank is destroyed by mixing of the medium and low temperature hot water. As a result, the hot water distribution in the hot water storage tank becomes uneven, and the hot water supply temperature tends to become unstable.

JP 2003-148809 A

  The present invention has been conceived under the circumstances as described above, and suppresses a problem that the hot water temperature becomes unstable during hot water supply operation after so-called full boiling, while suppressing hot water in the hot water storage tank. It is an object of the present invention to provide a hot water storage type hot water supply apparatus that can effectively and appropriately use the entire amount or almost the entire amount of hot water for hot water supply.

  In order to solve the above problems, the present invention takes the following technical means.

The hot water storage type hot water supply apparatus provided by the present invention is capable of storing hot water heated by using an external heat source device from the upper part to the inside, and a hot water pipe connected to the upper part of the stored hot water. And a plurality of temperature sensors for detecting the temperature of the hot water in the hot water storage tank, the hot water storage tank being capable of discharging hot water toward the hot water supply destination, and an interval in the vertical height direction of the hot water storage tank. And a determination means capable of determining whether or not the boiling of a predetermined heat storage state is completed based on the hot water temperature detected using the plurality of temperature sensors. And a first hot water circulation path capable of performing a first hot water circulation operation for sending hot water in the upper part of the hot water storage tank to the lower part of the hot water storage tank. Boil is complete When the effect of the decision is made it is characterized by being configured such that the first hot water circulation operation is performed.

According to such a configuration, the following effects can be obtained.
First, when the determination means determines that the hot water storage tank is full of heat storage, the hot water existing in the upper part of the hot water storage tank can be sent to the lower part of the hot water storage tank. Even if medium and low temperature hot water is present, these hot water and water can be mixed, and the total amount of hot water in the hot water storage tank can be made hot water or hot water close to this temperature. Therefore, although it is determined that the hot water storage tank is in a state of full heat storage, it is possible to eliminate the problem that part of the hot water is actually in a low temperature state. As a result, the amount of hot water that can be used for hot water supply can be increased and energy efficiency can be increased.
Second, in order to send high temperature hot water existing in the upper part of the hot water storage tank to the lower part of the hot water storage tank, unlike Patent Document 1, temperature stratification formed in the upper part of the hot water storage tank is prevented from collapsing. be able to. In addition, a hot water area in which hot water and medium / low temperature hot water are mixed is generated in the lower part of the hot water storage tank. Uniformity is achieved, resulting in hot water with little variation in temperature. From such a thing, the effect of stabilizing hot water supply temperature is also acquired.

  In the present invention, preferably, in the first hot water circulation operation, a temperature sensor provided at a lowermost part of the plurality of temperature sensors detects a temperature substantially the same as the hot water in the upper part of the hot water storage tank. It ends at the time, or is configured to end when the driving time of the pump used for the hot water feeding operation reaches a predetermined time.

  According to such a configuration, the necessary and sufficient amount of hot water sent from the upper part of the hot water storage tank to the lower part of the hot water storage tank is simply and accurately executed without using an expensive flow sensor or the like. Can do.

  In the present invention, preferably, the first hot water circulation operation is executed when the hot water boiling temperature is higher than the hot water supply set temperature, and is not executed when it is not.

  According to such a configuration, the hot water in the upper part of the hot water storage tank is fed into the lower part of the hot water tank and mixed, so that a lot of hot water lower than the set hot water temperature is generated in the hot water tank, which is wasteful. This can be prevented.

  In the present invention, preferably, the apparatus further comprises a second hot water circulation path capable of a second hot water circulation operation for sending hot water in the lower part of the hot water tank into the upper part of the hot water tank, When it is determined that the boiling in the heat storage full state is completed, when the boiling water boiling temperature is higher than the hot water supply set temperature and the temperature difference is less than a predetermined temperature, the first hot water circulation operation is performed. When the hot water boiling temperature is higher than the hot water supply set temperature and the temperature difference is equal to or higher than the predetermined temperature, the second hot water circulation operation is executed.

According to such a configuration, the following effects can be obtained.
First, when the hot water boiling temperature is slightly higher than the hot water supply set temperature, the first hot water circulation operation is executed. As described above, in the first hot water circulation operation, the hot water storage tank is used. Since the inner temperature stratification does not collapse, hot water supply at the hot water supply set temperature can be appropriately performed at the hot water supply destination. On the other hand, since the second hot water circulation operation is the same method as that of Patent Document 1 described above, the temperature stratification in the hot water storage tank is destroyed. However, since the second hot water circulation operation is executed when the hot water boiling temperature is considerably higher than the hot water supply set temperature, it is possible to supply hot water at the hot water supply set temperature to the hot water supply destination. .
In the first hot water circulation operation, since the medium / low temperature hot water and the high temperature hot water are mixed in the lower part of the hot water storage tank, the temperature detection by the temperature sensor at the bottom may be unstable. This is not the case with hot water circulation. Therefore, when the hot water temperature detected by the temperature sensor at the bottom is used as the control means for terminating the hot water circulation operation, the second hot water circulation operation is more preferable than the first hot water circulation operation. High-precision control is possible. Thus, according to the configuration of the present invention, the advantages of the first and second hot water circulation operations can be utilized.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

It is explanatory drawing which shows an example of the hot water storage type hot water supply apparatus which concerns on this invention. (A), (b) is principal part explanatory drawing which shows two types of hot water circulation operation | movement performed in the hot water storage type hot-water supply apparatus of FIG. It is a flowchart which shows the example of the operation control performed in the hot water storage type hot-water supply apparatus of FIG.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  A hot water storage type hot water supply apparatus A shown in FIG. 1 is a heat pump hot water supply apparatus, and is configured by combining a heat pump 1 and a hot water storage tank unit U.

The heat pump 1 is the same as a conventionally known one. For example, an evaporator 10, a compressor 11, and a condenser that absorb heat from air taken in using a fan 10 a into a circulation path of a refrigerant such as CO ₂ . A heat exchanger 12 for heating hot water and an expansion valve 13 are provided.

  The hot water storage tank unit U includes a hot water storage tank 2, an auxiliary heat source device 3, a control unit 4, and a plurality of piping sections described later connected to the hot water storage tank 2 and other parts. As will be described later with reference to FIG. 2, the plurality of piping portions can constitute first and second hot water circulation paths C1 and C2.

The lower part and the upper part of the hot water storage tank 2 are connected to the heat exchanger 12 of the heat pump 1 via pipes 50a and 50b. When the pump P1 provided in the pipe 50a is driven, the hot water in the lower part of the hot water storage tank 2 is sent to the heat exchanger 12 through the pipe 50a and heated, and then the hot water storage tank 2 through the pipe 50b. Returned to the top inside. The boiling of the hot water is performed in this way, and hot hot water is sequentially accumulated from the upper side to the lower side in the hot water storage tank 2. The hot water storage tank 2 is provided with a plurality of temperature sensors Sa for detecting the internal hot water temperature at appropriate intervals in the vertical direction, and the temperature distribution of the hot water in the hot water storage tank 2 and It is possible to judge the amount of heat storage based on this.

  A water inlet pipe 61 having a water inlet 61a and a three-way valve V3 are connected to the lower part of the hot water tank 2, and a hot water pipe 62 having a hot water outlet 62a is connected to the upper part of the hot water tank 2. When the hot water tap 90 piped to the hot water outlet 62a is opened, the hot water in the hot water storage tank 2 flows out into the hot water outlet pipe 62 due to the water pressure in the hot water storage tank 2, and enters the hot water tap 90 from the outlet 62a. Supplied. A pipe 64 having a hot water outlet 64 a for hot water supply to the bathtub 94 is branched and connected to the hot water pipe 62. Further, the hot water outlet pipe 62 is provided with a temperature control valve S2 and a hot water temperature control mixing valve V2 to which the branch pipe 61b of the water inlet pipe 61 is connected. The mixing valve V2 allows hot water passing through the branch pipe 61b of the inlet pipe 61 to flow into the hot water in the outlet pipe 62 and changes the mixing ratio thereof, thereby changing the hot water supply temperature to the hot water supply set temperature (remote control). 40 can be adjusted to a hot water supply temperature set by the user or a hot water supply temperature set by the main control unit 4 according to various conditions. In this embodiment, the heat exchanger 92 for heating the heat medium which distribute | circulates the inside of the piping 93 provided with the pump P3 for the hot water heating terminal 91 is also comprised, and heat exchange is carried out by the path | route mentioned later different from the above. The water heater 92 is also capable of supplying hot water.

  The auxiliary heat source unit 3 is for performing hot water heating when hot water runs out in the hot water storage tank 2, and its configuration is the same as that of, for example, a gas instantaneous water heater. Specifically, the auxiliary heat source unit 3 includes a burner 30 and a heat exchanger 31, and is configured so that hot water supplied to the heat exchanger 31 can be quickly heated by the burner 30. The incoming water side piping part 70a of the auxiliary heat source unit 3 is connected to the upper part of the hot water storage tank 2 via the pump P2 and the three-way valve V1. The hot water outlet side piping part 70b of the auxiliary heat source unit 3 has an on-off valve V4, is connected to the hot water outlet pipe 62, and a piping part 71 provided with a heat exchanger 92 is branched and connected. For this reason, by switching between the three-way valve V1 and the on-off valve V4, hot water heated through the auxiliary heat source unit 3 can be supplied to the hot water tap 90, the bathtub 94, and the heat exchanger 92, respectively.

In the hot water storage tank unit U, the first and second hot water circulation paths C1 and C2 can be formed as shown by the thick lines in FIGS. 2 (a) and 2 (b).
A first hot water circulation path C <b> 1 shown in FIG. 2A is a hot water circulation path for sending hot water in the upper part of the hot water storage tank 2 to the lower part of the hot water storage tank 2. In the first hot water circulation path C1, when the pump P2 is driven, the hot water in the upper part of the hot water storage tank 2 flows out to the water inlet side piping part 70a of the auxiliary heat source unit 3 and passes through the auxiliary heat source unit 3. Thereafter, it passes through the hot water side piping part 70b, the piping part 71, and the three-way valve V3 and flows into the lower part of the hot water storage tank 2. A second hot water circulation path C <b> 2 shown in FIG. 2B is a hot water circulation path for sending hot water in the lower part of the hot water storage tank 2 to the upper part of the hot water storage tank 2. The second hot water circulation path C2 is configured by using a pipe part 63 that connects the three-way valves V1 and V3. When the pump P2 is driven, the hot water in the lower part of the hot water storage tank 2 is transferred to the pipe part 63. After flowing out and passing through the auxiliary heat source unit 3, it passes through the on-off valve V 4 and part of the hot water discharge pipe 62 and flows into the upper part of the hot water storage tank 2. Such switching of the first and second hot water circulation paths C1 and C2 is performed by valve switching control by the control unit 4.

  The control unit 4 corresponds to an example of a determination unit referred to in the present invention, and is configured using a microcomputer or the like. This control unit 4 has a learning ability to predict future heat demand based on past heat demand (hot water supply operation results). Based on the heat demand prediction and the like, operation control of each part of the hot water storage tank unit U Perform data processing. In addition, in cooperation with a control unit (not shown) of the heat pump 1, operation control of the entire hot water storage type hot water supply apparatus A is also executed. In addition, the control unit 4 is configured to perform characteristic control as will be described later when the so-called total amount of hot water in the hot water storage tank 2 is heated.

  Next, the operation of the hot water storage type hot water supply apparatus A will be described. In addition, an example of the operation processing procedure of the control unit 4 will be described with reference to the flowchart of FIG.

  First, after starting the so-called boiling of hot water in the hot water storage tank 2, the control unit 4 stores the heat in the hot water storage tank 2 when a predetermined boiling temperature is detected by all the temperature sensors Sa. It is determined that the vehicle is full, and the boiling operation is terminated (S1, S2: YES, S3). For this reason, even after the completion of boiling, there is a possibility that medium-low temperature hot water that does not reach the boiling temperature exists in the hot water storage tank 2 in a region below the lowest temperature sensor Sa1.

  Next, the control unit 4 compares the boiling temperature Ta of the hot water with the hot water supply set temperature Tb, the hot water boiling temperature Ta is higher than the hot water supply set temperature Tb, and the temperature difference between them is less than a predetermined value. In some cases, the first hot water circulation operation by driving the pump P2 is started (S4: YES, S5: YES, S6). This first hot water circulation operation is an operation of flowing hot water into the first hot water circulation path C1 described with reference to FIG. 2 (a). In this operation, the hot water in the upper part of the hot water storage tank 2 is heated. It is fed into the lower part of the hot water storage tank 2. For this reason, even if medium-low temperature hot water exists in the lower part of the hot water storage tank 2, as a result of mixing high temperature hot water with these, these mixed hot water becomes high temperature hot water or near hot water and originally existed. Medium and low temperature hot water can be substantially eliminated.

  When the temperature detected by the temperature sensor Sa1 at the bottom and the temperature sensor Sb of the outlet pipe 62 becomes substantially the same after the start of the first hot water circulation operation, the driving of the pump P2 is stopped at that time, and the first The hot water circulation operation ends (S7: YES, S8). When high temperature hot water flows into the lower part of the hot water storage tank 2 and this high temperature hot water flows up to the height of the temperature sensor Sa1 at the bottom, the temperature detected by the temperature sensors Sa1 and Sb becomes substantially the same. Therefore, if the first hot water circulation operation is terminated at such timing, the medium / low temperature hot water existing in the lower part of the hot water tank 2 is substantially eliminated, and the high temperature to the lower part of the hot water tank 2 is increased. It is possible to make the inflow of hot water not excessive or insufficient. Further, it is not necessary to use an expensive flow rate sensor in controlling the inflow amount of high-temperature hot water.

  When the first hot water circulation operation described above is executed, the total amount of hot water in the hot water storage tank 2 can be made hot water or hot water having a temperature close thereto. Therefore, even though the controller 4 determines that the hot water storage tank 2 is full of heat storage, the fact that some hot water is actually in a low temperature state is eliminated. For this reason, the utilization frequency of the auxiliary heat source unit 3 can be lowered and the energy efficiency can be increased. In the first hot water circulation operation, high temperature hot water existing in the upper part of the hot water storage tank 2 is sent to the lower part of the hot water storage tank 2 so that the temperature stratification in the upper part of the hot water storage tank 2 does not collapse. Can do. In addition, the mixed hot / cold hot / cold hot water generated in the lower part of the hot water storage tank 2 is not immediately discharged from the hot water storage tank 2 even if the hot water supply operation is started thereafter. As time elapses, the temperature is made uniform, so that the hot water has little variation in temperature. Therefore, even when the temperature difference between the boiling temperature Ta of the hot water and the set temperature Tb of the hot water is smaller than a predetermined value, the hot water can be supplied at a stable temperature without the hot water temperature being lower than the set temperature of the hot water. is there.

On the other hand, unlike the above, when the boiling temperature Ta of the hot water is higher than the hot water supply set temperature Tb and the temperature difference is larger than a predetermined value, the second hot water circulation operation by driving the pump P2 is performed. Is started (S4: YES, S5: NO, S9). The second hot water circulation operation is an operation of flowing hot water into the second hot water circulation path C2 described with reference to FIG. 2B. Is fed into the upper part of the hot water storage tank 2 and mixed with hot hot water. Therefore, it is possible to substantially eliminate the medium / low temperature hot water existing at the lowermost portion in the hot water storage tank 2. Thereafter, as in the case of the first hot water circulation operation, the driving of the pump P2 is stopped when the temperatures detected by the temperature sensors Sa1 and Sb become substantially the same, and the second hot water circulation operation is ended (S7). : YES, S8).

  According to the second hot water circulating operation, the medium and low temperature hot water is mixed with the high temperature hot water in the upper part of the hot water storage tank 2, so that the temperature stratification of the high temperature hot water is broken. Therefore, the hot water supply temperature tends to become unstable. However, in the present embodiment, the second hot water circulation operation is executed only when the boiling temperature Ta of the hot water is considerably higher than the hot water supply set temperature Tb. When hot water is supplied, it is possible to appropriately avoid that the hot water supply temperature is lower than the hot water supply set temperature Tb.

  During the second hot water circulation operation, mixing of the medium / low temperature hot water and the high temperature hot water is not performed in the vicinity of the temperature sensor Sa1 at the bottom. On the other hand, during the first hot water circulating operation, mixing of the medium / low temperature hot water and the high temperature hot water is performed in the vicinity of the temperature sensor Sa1 at the bottom. For this reason, in the second hot water circulation operation, the hot water temperature detected by the temperature sensor Sa1 is more stable than in the first hot water circulation operation, and accurate temperature measurement is possible. For this reason, in terms of hot water flow rate control, the second hot water circulation operation can be more accurate than the first hot water circulation operation. In the second hot water circulation operation, it is possible to more accurately prevent the pump P2 from operating more than necessary. When the second hot water circulation path operation is executed instead of the first hot water circulation operation, the advantages as described above are obtained.

  Unlike the case described above, when the boiling temperature Ta of hot water is not higher than the hot water supply set temperature Tb, the first or second hot water circulation operation as described above is not performed (S4: NO, End). If it does in this way, it will be avoided that the hot water in hot water storage tank 2 is not so high temperature, and that the temperature falls further by being mixed with medium-low temperature hot water.

  The present invention is not limited to the contents of the above-described embodiment. The specific configuration of each part of the hot water storage type hot water supply apparatus according to the present invention can be variously modified within the range intended by the present invention.

  In the above-described embodiment, when the temperatures detected by the temperature sensors Sa1 and Sb are substantially the same, the first and second hot water circulation operations are terminated. The specific means for terminating is not limited to this. For example, it is possible to compare the detected temperature of the temperature sensor Sa1 with that of the uppermost temperature sensor Sa2 and terminate the operation when they reach substantially the same temperature. Further, since the amount of the medium / low temperature hot water existing below the lowest temperature sensor Sa1 can be known in advance, it is also possible to adopt means for terminating the above operation by setting the operation time of the pump P2. it can. Of course, the flow sensor may be used to end the operation when the measured value of the hot water circulation flow rate reaches a predetermined amount.

  The present invention requires that the first hot water circulation operation is executed under a certain condition, but the second hot water circulation operation is not necessarily executed. The external heat source device for heating the hot water in the hot water storage tank is not limited to the heat pump, and other heat source devices can also be used.

A Hot water storage hot water supply devices C1, C2 First and second hot water circulation paths U Hot water storage tank unit Sa Temperature sensor 1 Heat pump (external heat source machine)
2 Hot water storage tank 4 Control part (judgment means)

Claims (4)

Hot water heated using an external heat source machine can be stored by flowing into the inside from the top, and the stored hot water can be discharged toward the hot water supply destination via a hot water pipe connected to the top. A hot water storage tank,
A plurality of temperature sensors provided at intervals in the vertical height direction of the hot water storage tank, and for detecting the hot water temperature in the hot water storage tank;
A determination means capable of determining whether or not the boiling of the predetermined heat storage state is completed based on the hot water temperature detected using the plurality of temperature sensors;
A hot water storage hot water supply device comprising:
A first hot water circulation path capable of a first hot water circulation operation for sending hot water in the upper part of the hot water storage tank to the lower part of the hot water storage tank;
The hot water storage hot water supply system is configured such that the first hot water circulation operation is executed when the determination means determines that the boiling of the heat storage full state is completed. apparatus. The hot water storage type hot water supply device according to claim 1,
The first hot water circulation operation ends when the temperature sensor provided at the lowermost of the plurality of temperature sensors detects a temperature substantially the same as the hot water in the upper part of the hot water storage tank, or A hot water storage type hot water supply device configured to end when a driving time of a pump used for hot water feeding operation reaches a predetermined time. The hot water storage type hot water supply device according to claim 1 or 2,
The first hot water circulation operation is performed when the hot water boiling temperature is higher than the hot water supply set temperature, and is not performed when the hot water boiling temperature is not higher. A hot water storage type hot water supply apparatus according to any one of claims 1 to 3,
A second hot water circulation path capable of a second hot water circulation operation for sending the hot water in the lower part of the hot water tank to the upper part of the hot water tank;
When it is determined in the determination means that the boiling in the heat storage full state is completed, when the boiling water boiling temperature is higher than the hot water supply set temperature and the temperature difference is less than a predetermined temperature, the first While hot water circulation operation is performed,
A hot water storage type hot water supply apparatus configured to perform the second hot water circulation operation when the hot water boiling temperature is higher than a preset hot water supply temperature and the temperature difference is equal to or higher than the predetermined temperature.

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