JP2017194248A - Heat storage water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat storage water heater for sufficiently suppressing attachment of scale.SOLUTION: A heat storage water heater includes: a first circulation circuit in which a first water feeding part for feeding a heating medium for heat storage, a supply heat exchanger for heating the heating medium for heat storage which has been fed by the first water feeding part and a heat storage tank for storing the heating medium for heat storage are connected by first piping; and a second circulation circuit in which a second water feeding part for feeding the heating medium for heat storage stored in the heat storage tank, the heat storage tank and a hot water supply unit which heats the heating medium by exchanging heat with the heating medium for heat storage fed by the second water feeding part are connected by second piping. The hot water supply unit includes: a main heat exchanger for heating the heating medium; and a sub heat exchanger provided on the upstream side of the main heat exchanger in the second circulation circuit, and for heating the heating medium in which heat has been exchanged with the heating medium for heat storage in the main heat exchanger.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat storage water heater that supplies hot water using heat stored in a heat storage tank.

  2. Description of the Related Art Conventionally, there is known a water heater that stores hot heat supplied from a heat source device in a heat storage tank via a heat medium and supplies hot water using the heat stored in the heat storage tank. Since such a water heater uses water, it has a problem that scale is deposited. The water used in the water heater contains, for example, chlorine, calcium, magnesium, and the like, and the scale is more likely to be deposited as the water temperature becomes higher, for example, 65 ° C. or higher. If the deposited scale adheres to the piping or the like, the circulation of water is hindered, and as a result, the piping may be blocked.

  When water is heated by the heat exchanger, the water is gradually heated while passing through the flow path inside the heat exchanger. For this reason, scale deposition tends to occur after flowing out of the heat exchanger. For the purpose of suppressing the scale that can be deposited on the outlet side of the heat exchanger, Patent Document 1 has a first heat exchanger and a second heat exchanger, and uses exhaust gas discharged from the fuel cell. A heat exchanger for hot water supply for warming water is disclosed. The first heat exchanger is disposed on the upstream side of the exhaust gas flow and on the downstream side of the water flow. The second heat exchanger is disposed on the downstream side of the exhaust gas flow, and is disposed on the upstream side of the water flow. Therefore, the water is further heated in the first heat exchanger after being heated in the second heat exchanger. Thereby, high temperature water flows through the water-side flow path of the first heat exchanger. Here, the total cross-sectional area of the water-side flow path of the first heat exchanger is smaller than the total cross-sectional area of the water-side flow path of the second heat exchanger. For this reason, the speed of the water which flows into the water side channel of the 1st heat exchanger is faster than the speed of the water which flows into the water side channel of the 2nd heat exchanger. Thereby, patent document 1 tries to suppress that a scale adheres to the water side flow path of a 1st heat exchanger.

JP 2012-117723 A

  However, since the hot water supply heat exchanger disclosed in Patent Document 1 uses exhaust gas, the temperature at which water is heated cannot be controlled. For this reason, hot water always flows through the water-side flow path of the first heat exchanger. In this way, since high-temperature water always flows, the scale tends to adhere.

  The present invention has been made to solve the above-described problems, and provides a heat storage water heater that sufficiently suppresses adhesion of scale.

  A heat storage hot water supply apparatus according to the present invention includes a first water supply unit that supplies a heat storage heat medium, a supply heat exchanger that heats the heat storage heat medium supplied by the first water supply unit, and a heat storage heat medium. The 1st circulation circuit where the heat storage tank to store was connected by the 1st piping, the 2nd water supply part which supplies the heat storage heat storage stored in the heat storage tank, the heat storage tank, and the 2nd water supply part A hot water supply unit that exchanges heat with the heat storage heat medium fed by the water to heat the heating medium, and is connected by a second pipe, and the hot water supply unit heats the heating medium. A heat exchanger, and a sub heat exchanger that is provided upstream of the main heat exchanger in the second circulation circuit and heats the heating medium heat-exchanged with the heat storage heat medium in the main heat exchanger.

  According to the present invention, the heat storage water heater includes the first circulation circuit and the second circulation circuit to which the heat storage tank is connected. For this reason, the temperature of the heat storage heat medium stored in the heat storage tank can be controlled, and the temperature of the heating medium flowing in the hot water supply unit can also be controlled. Therefore, scale adhesion can be sufficiently suppressed.

It is a circuit diagram which shows the thermal storage water heater 1 which concerns on Embodiment 1 of this invention. It is a graph which shows the relationship between the temperature of the heating medium in Embodiment 1 of this invention, and the adhesion amount of a scale. It is a circuit diagram which shows the thermal storage water heater 100 which concerns on Embodiment 2 of this invention. It is a circuit diagram which shows the thermal storage water heater 200 which concerns on Embodiment 3 of this invention.

Embodiment 1 FIG.
Hereinafter, an embodiment of a heat storage water heater according to the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing a heat storage water heater 1 according to Embodiment 1 of the present invention. Based on this FIG. 1, the thermal storage water heater 1 is demonstrated. As shown in FIG. 1, the heat storage water heater 1 includes a heat pump device 20, a first circulation circuit 3, a second circulation circuit 4, a water pipe 5, a temperature detection unit 6, and a flow rate detection unit 7. The control unit 10 is provided.

(Heat pump device 20)
The heat pump device 20 includes a heat pump circulation circuit 2 in which a compressor 21, a supply heat exchanger 22, an expansion unit 23, and a heat source heat exchanger 24 are connected by a heat pump pipe, and a heat exchange heat medium flows, and an outside air blower 25. . The compressor 21 compresses the heat exchanging heat medium, and pumps the heat exchanging heat medium in a gas phase to increase the temperature and pressure. The supply heat exchanger 22 heats the heat storage heat medium by exchanging heat between the heat exchange heat medium and the heat storage heat medium flowing in the first circulation circuit 3. In the supply heat exchanger 22, the heat exchange heat medium and the heat storage heat medium pass through separate flow paths, respectively, and the heat exchange heat medium and the heat storage heat medium are not mixed.

  The expansion part 23 expands by depressurizing the heat exchange heat medium, and lowers the temperature and pressure of the heat exchange heat medium in a high-pressure liquid phase state to a gas-liquid mixed phase state. The heat source heat exchanger 24 exchanges heat between outdoor air and a heat exchange heat medium. The outdoor air blower 25 is provided in the vicinity of the heat source heat exchanger 24 and blows outdoor air to the heat source heat exchanger 24. The heat exchange heat medium is, for example, a hydrocarbon-based refrigerant or a carbon dioxide refrigerant that is gas-liquid two-phased within a range of temperature or pressure to be used.

  The heat pump device 20 uses the condensation and vaporization of the heat exchange heat medium flowing in the heat pump circuit 2 to release the heat absorbed from the outdoor air to the heat storage heat medium. Note that the heat pump device 20 efficiently moves heat between the outdoor air and the heat storage heat medium via the heat exchange heat medium as compared with the power required for the compression of the compressor 21.

(First circulation circuit 3)
In the first circulation circuit 3, the first water supply section 31, the supply heat exchanger 22, and the heat storage tank 32 are connected by the first pipe 30, and the heat storage heat medium flows. The 1st water supply part 31 is a pump provided in the 1st return path 30b between the supply heat exchanger 22 and the heat storage tank 32, for example, and supplies the heat storage heat medium in the 1st circulation circuit 3. It is. The supply heat exchanger 22 heats the heat storage heat medium supplied by the first water supply unit 31. The heat storage tank 32 is a container sealed with respect to the outside, and a predetermined amount of heat storage heat storage medium is always accommodated therein. The inside of the heat storage tank 32 is a high temperature region, and for example, the temperature of the heat storage heat medium that stays inside is 90 ° C. On the other hand, the inside of the heat storage tank 32 is a low temperature region. For example, the temperature of the heat storage heat medium staying in the inside is 35 ° C. In the heat storage tank 32, the temperature of the heat storage heat medium gradually decreases from the high temperature region to the low temperature region, and the high temperature region and the low temperature region are not clearly divided. In this way, the heat storage tank 32 stores heat by recognizing a high-temperature heat storage heat medium, and the amount of heat storage is determined by the ratio of the high-temperature heat storage heat medium and the low-temperature heat storage heat medium. The

  And the upper part of the heat storage tank 32 and the downstream side of the supply heat exchanger 22 are connected by the 1st outward path 30a of the 1st piping 30, and the lower part of the heat storage tank 32 and the upstream side of the 1st water supply part 31 are the 1st. The first piping 30 is connected by a first return path 30b. The heat storage tank 32 pushes the heat storage heat medium into the first return path 30b downstream of the heat storage tank 32 in response to the heat storage heat medium flowing from the first forward path 30a downstream of the supply heat exchanger 22. Discharge. The heat storage heat medium is an antifreeze liquid having a low freezing point that maintains a liquid state even at low temperatures by mixing glycerin with water, for example. In the supply heat exchanger 22, the flow of the heat exchange heat medium flowing through the heat pump circulation circuit 2 and the flow of the heat storage heat medium flowing through the first circulation circuit 3 are opposed to each other.

(Second circulation circuit 4)
In the second circulation circuit 4, the second water supply section 41, the heat storage tank 32, and the hot water supply unit 42 are connected by the second pipe 40, and the heat storage heat medium flows. The 2nd water supply part 41 is a pump provided in the 2nd return path 40b between the heat storage tank 32 and the hot water supply unit 42, for example, and supplies the heat storage heat medium stored in the heat storage tank 32. Here, the upper part of the heat storage tank 32 and the upstream side of the hot water supply unit 42 are connected by the second forward path 40a of the second pipe 40, and the lower part of the heat storage tank 32 and the downstream side of the first water supply unit 31 are second. The pipes 40 are connected by a second return path 40b. In the hot water supply unit 42, the heat storage heat medium flows from the second forward path 40 a on the downstream side of the heat storage tank 32, and discharges the heat storage heat medium to the second return path 40 b on the downstream side of the heat storage tank 32.

(Hot water supply unit 42)
The hot water supply unit 42 heats the heating medium by exchanging heat with the heat storage heat medium fed by the second water feeding section 41, and has a main heat exchanger 43 and a sub heat exchanger 44. . The main heat exchanger 43 is provided on the upstream side of the second water supply section 41 in the second circulation circuit 4 and heats the heating medium. The main heat exchanger 43 is, for example, a high-performance plate heat exchanger. The auxiliary heat exchanger 44 is provided on the upstream side of the main heat exchanger 43 in the second circulation circuit 4, and further heats the heating medium heat-exchanged with the heat storage heat medium in the main heat exchanger 43. . The auxiliary heat exchanger 44 is, for example, a coil-in-tank heat exchanger.

(Water pipe 5)
The water pipe 5 is a channel through which a heating medium flows, and has a water supply channel 52 and a hot water supply channel 53 that connect the water supply source 51 and the hot water supply unit 54. The water supply source 51 is a supply source of the heating medium, and the hot water supply unit 54 is a hot water supply destination of the heating medium. The water supply path 52 connects the water supply source 51 and the main heat exchanger 43 of the hot water supply unit 42. The hot water supply path 53 connects the auxiliary heat exchanger 44 of the hot water supply unit 42 and the hot water supply unit 54. The heating medium is, for example, tap water, and flows into the hot water supply unit 42 from the water supply source 51 through the water supply path 52 of the water pipe 5, flows out of the hot water supply unit 42, and then passes through the hot water supply path 53 of the water pipe 5. To the hot water supply unit 54. Thus, in the hot water supply unit 42, the flow of the heat storage heat medium flowing in the second circulation circuit 4 and the flow of the heating medium flowing in the water pipe 5 are opposed to each other.

(Temperature detector 6 and flow rate detector 7)
The temperature detector 6 is attached to the heat storage tank 32 and detects the temperature of the heat storage heat medium stored in the heat storage tank 32. The flow rate detector 7 is attached to the hot water supply passage 53 of the water pipe 5 and detects the flow rate of the heating medium flowing out from the auxiliary heat exchanger 44 of the hot water supply unit 42.

(Control unit 10)
Based on the hot water supply set temperature set by the user, the detection result of the temperature detection unit 6, the detection result of the flow rate detection unit 7, and the like, the control unit 10 includes the compressor 21, the expansion unit 23, the outside air blower 25, and the first water supply. Control objects such as the unit 31 and the second water supply unit 41 are controlled.

  FIG. 2 is a graph showing the relationship between the temperature of the heating medium and the amount of scale attached in Embodiment 1 of the present invention. In FIG. 2, the horizontal axis represents the temperature of the heating medium (° C.), and the vertical axis represents the amount of scale attached (mm). Next, the scale adhering to the inside of the water pipe 5 will be described. Inside the water pipe 5, a foreign substance called a scale is generated due to the quality of the heating medium such as water to be used and accumulates on the inner surface of the water pipe 5. There is a possibility that the scale is peeled off and reattached inside the water pipe 5 to block the flow path of the water pipe 5. Here, the higher the temperature of the heating medium, the easier the scale is deposited.

  As shown in FIG. 2, no scale is deposited until the temperature of the heating medium is 50 ° C. When the temperature of the heating medium exceeds 50 ° C., the amount of scale attached gradually increases. Note that FIG. 2 illustrates the case of hard water having a high hardness such as in Europe. In the case of soft water having a low hardness as in Japan, the temperature of the heating medium at which scale can be generated is water having a high hardness. Higher than the case. That is, scale precipitation occurs at a lower temperature in hard water than in soft water.

(Flow of heat exchange heat medium in heat pump circulation circuit 2)
Next, the flow of the heat exchange heat medium in the heat pump circuit 2 will be described. In the heat pump circulation circuit 2, the heat exchange heat medium sucked into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature and high-pressure gas state. The high-temperature and high-pressure gaseous refrigerant discharged from the compressor 21 flows into the supply heat exchanger 22, and is condensed by heat exchange with the heat storage heat medium flowing in the first circulation circuit 3 in the supply heat exchanger 22. Liquefaction. At this time, the heat storage heat medium is heated. The condensed refrigerant in the liquid state flows into the expansion unit 23 and is expanded and depressurized in the expansion unit 23 to be in a gas-liquid two-phase state. Then, the gas-liquid two-phase refrigerant flows into the heat source heat exchanger 24, and in the heat source heat exchanger 24, heat is exchanged with the outdoor air blown by the outdoor air blower 25 to evaporate gas. The evaporated refrigerant in the gas state is sucked into the compressor 21.

(Flow of the heat storage heat medium in the first circulation circuit 3)
Next, the flow of the heat storage heat medium in the first circulation circuit 3 will be described. In the first circulation circuit 3, the heat storage heat medium fed by the first water feeding unit 31 flows into the supply heat exchanger 22, and the heat exchange heat flowing into the heat pump circulation circuit 2 in the supply heat exchanger 22. Heat is exchanged with the medium. The heated heat storage heat medium passes through the first forward path 30 a of the first pipe 30, flows into the heat storage tank 32 from the upper part of the heat storage tank 32, and is stored in the heat storage tank 32. As a result, a high-temperature heat storage heat medium is stored above the inside of the heat storage tank 32. Then, the heat storage heat medium flowing out from the lower part of the heat storage tank 32 to the first return path 30 b of the first pipe 30 returns to the first water supply unit 31 again. As described above, the heat storage heat medium circulates through the first circulation circuit 3.

(Flow of heat storage heat storage in the second circulation circuit 4)
Next, the flow of the heat storage heat medium in the second circulation circuit 4 will be described. In the second circulation circuit 4, the heat storage heat medium supplied by the second water supply unit 41 passes from the lower part of the heat storage tank 32 to the inside of the heat storage tank 32 through the second return path 40 b of the second pipe 40. It flows in and is stored in the heat storage tank 32. The high-temperature heat storage heat medium stored above the heat storage tank 32 flows out from the upper part of the heat storage tank 32 to the second forward path 40 a of the second pipe 40. The heat storage heat medium that has flowed out passes through the second forward path 40a of the second pipe 40 and flows into the auxiliary heat exchanger 44 of the hot water supply unit 42. In the auxiliary heat exchanger 44, the heating medium flowing into the water pipe 5 and Heat exchanged and cooled. At this time, the heating medium is heated. Thereafter, the cooled heat storage heat medium flows into the main heat exchanger 43 of the hot water supply unit 42, and in the main heat exchanger 43, heat is exchanged with the heating medium flowing in the water pipe 5 and further cooled. At this time, the heating medium is heated. The cooled heat storage heat storage medium returns to the second water supply unit 41 again. Thus, the heat storage heat medium circulates through the second circulation circuit 4.

(Flow of heating medium in water pipe 5)
Next, the flow of the heating medium in the water pipe 5 will be described. The heating medium supplied from the water supply source 51 passes through the water supply path 52 and flows into the main heat exchanger 43 of the hot water supply unit 42, and the heat storage heat medium flowing into the second circulation circuit 4 in the main heat exchanger 43. Heat is exchanged with. Thereafter, the heated heating medium flows into the auxiliary heat exchanger 44 of the hot water supply unit 42, and in the auxiliary heat exchanger 44, heat is exchanged with the heat storage heat medium flowing in the second circulation circuit 4 and further heated. . The heated heating medium passes through the hot water supply path 53 and reaches the hot water supply section 54.

(Heat storage operation)
Next, the heat storage operation will be described. The heat storage operation is an operation in which a high-temperature heat storage heat medium is stored in the heat storage tank 32, and is performed when the heat storage heat medium flows into the first circulation circuit 3. The heat storage heat medium heated by the supply heat exchanger 22 flows into the upper part of the heat storage tank 32 and is stored in the heat storage tank 32. As a result, a high-temperature heat storage heat medium is stored above the inside of the heat storage tank 32. Then, the heat storage heat medium flowing out from the lower part of the heat storage tank 32 to the first return path 30 b of the first pipe 30 returns to the first water supply unit 31 again.

  Here, the heat storage operation performed when the temperature of the heat storage heat medium stored in the heat storage tank 32 is reduced will be described. When the temperature of the heat storage heat medium detected by the temperature detection unit 6 attached to the heat storage tank 32 is equal to or lower than a predetermined temperature threshold, the control unit 10 reduces the amount of heat stored in the heat storage tank 32. Judge. In this case, the control unit 10 drives the heat pump device 20. As a result, in the heat pump circulation circuit 2, the heat exchange heat medium compressed by the compressor 21 and having a high temperature flows into the supply heat exchanger 22.

  Further, the control unit 10 drives the first water supply unit 31. As a result, in the first circulation circuit 3, the heat storage heat medium fed by the first water feeding section 31 flows into the supply heat exchanger 22, and heat exchange with the heat exchange heat medium is performed in the supply heat exchanger 22. Heated. In this case, the control unit 10 controls the heating temperature of the heat storage heat medium by controlling the temperature and flow rate of the heat exchange heat medium flowing into the supply heat exchanger 22 by the heat pump device 20. Further, the control unit 10 controls the heating temperature of the heat storage heat medium by controlling the flow rate of the heat storage heat medium circulated by the first water supply unit 31.

  The heat storage heat medium heated in the supply heat exchanger 22 flows into the upper part of the heat storage tank 32 through the first forward path 30 a of the first pipe 30 and is stored in the heat storage tank 32. As a result, a high-temperature heat storage heat medium is stored above the inside of the heat storage tank 32. The temperature of the heat storage heat medium stored above the inside of the heat storage tank 32 is slightly higher than the set hot water supply temperature required by the hot water supply unit 54, for example, 90 ° C. Thereafter, the heat storage heat medium flowing out from the lower part of the heat storage tank 32 to the first return path 30 b of the first pipe 30 returns to the first water supply unit 31 again. The temperature of the heat storage heat medium flowing out from the lower part of the heat storage tank 32 is, for example, 35 ° C.

(Hot water operation)
Next, the hot water supply operation will be described. The hot water supply operation is an operation in which a low-temperature heating medium supplied from the water supply source 51 is heated and sent to the hot water supply unit 54. When the flow rate detection unit 7 attached to the hot water supply path 53 of the water pipe 5 detects that the heating medium has flowed into the hot water supply path 53, the control unit 10 determines to start the hot water supply operation. In this case, the control unit 10 drives the second water supply unit 41. As a result, in the second circulation circuit 4, a heat storage heat medium having a high temperature, for example, 90 ° C. flows from the upper part of the heat storage tank 32 into the sub heat exchanger 44 through the second forward path 40 a of the second pipe 40. Then, it flows into the main heat exchanger 43.

  The hot water supply set temperature is set, for example, between about 45 ° C. and 80 ° C., and the heat storage heat medium flowing in the second circulation circuit 4 and the heating medium passing through the water supply path 52 have respective temperatures and flow rates. Depending on the specific heat, various temperature patterns can be obtained. Therefore, the temperature of the heating medium passing through the water supply passage 52 is controlled to be the hot water supply set temperature by controlling the rotation frequency of the second water supply unit 41.

  Here, the case where the temperature of the heating medium supplied from the water supply channel 52 is 20 ° C., for example, and the set hot water supply temperature is 45 ° C. will be described. In ordinary households, a relatively low temperature hot water supply of about 45 ° C. or less is usually required. The low temperature, for example, 20 ° C. heating medium supplied from the water supply source 51 flows into the main heat exchanger 43 through the hot water supply passage 53 of the water pipe 5, and flows into the second circulation circuit 4 in the main heat exchanger 43. Heat exchange with the heat storage heat medium. Then, the heating medium flows into the sub heat exchanger 44, and heat exchange is performed with the heat storage heat medium flowing in the second circulation circuit 4 in the sub heat exchanger 44. The temperature of the heating medium rises from 20 ° C. to 45 ° C. in the main heat exchanger 43 and the sub heat exchanger 44. The heating medium heated to 45 ° C. is supplied with hot water to the hot water supply section 54 through the hot water supply passage 53.

  Next, the case where the temperature of the heating medium supplied from the water supply path 52 is 20 ° C. and the set hot water supply temperature is 80 ° C. will be described. Even in ordinary households, although it is infrequent, for example, a dishwasher may require a relatively hot water supply of about 80 ° C. The low temperature, for example, 20 ° C. heating medium supplied from the water supply source 51 flows into the main heat exchanger 43 through the hot water supply passage 53 of the water pipe 5, and flows into the second circulation circuit 4 in the main heat exchanger 43. Heat exchange with the heat storage heat medium. At this time, since the temperature of the heat storage heat medium flowing in the main heat exchanger 43 is set to 45 ° C. or less, for example, the temperature of the heating medium rises to about 45 ° C.

  Then, the heating medium flows into the auxiliary heat exchanger 44 and is exchanged with the heat storage heat medium flowing through the second circulation circuit 4 in the auxiliary heat exchanger 44, and the temperature rises to 80 ° C. The heating medium heated to 80 ° C. is supplied with hot water to the hot water supply section 54 through the hot water supply passage 53. Here, the auxiliary heat exchanger 44 reduces the temperature of the heat storage heat medium flowing out from the auxiliary heat exchanger 44 and flowing into the main heat exchanger 43 to 45 ° C. or less even during maximum heat exchange or maximum temperature hot water supply. Has the ability to reduce. Thereby, the temperature of the heat storage heat medium flowing in the main heat exchanger 43 is lowered to 45 ° C. or less. Here, 45 ° C. is the temperature of the heating medium at which scale begins to precipitate as shown in FIG. 2, and is a temperature slightly lower than about 50 ° C.

  In both cases where the set hot water supply temperature is 45 ° C. and 80 ° C., the heat storage heat medium flows out of the main heat exchanger 43, and then the temperature decreases to a low temperature, for example, 35 ° C. When hot water supply to the hot water supply unit 54 is continued, the high-temperature heat storage heat medium stored in the heat storage tank 32 gradually decreases. That is, in the heat storage tank 32, the lower internal low temperature region gradually increases and the internal high temperature region gradually decreases. If all of the heat storage tank 32 is in a low temperature region, hot water supply at a hot water supply set temperature, for example, 80 ° C. is not performed. Therefore, when the low temperature region of the heat storage tank 32 increases, the above-described heat storage operation is performed.

  According to the first embodiment, the heat storage water heater 1 includes the first circulation circuit 3 and the second circulation circuit 4 to which the heat storage tank 32 is connected. For this reason, the temperature of the heat storage heat medium stored in the heat storage tank 32 can be controlled, and the temperature of the heating medium flowing in the hot water supply unit 42 can also be controlled. Therefore, scale adhesion can be sufficiently suppressed. For example, by controlling the first water supply unit 31 and the second water supply unit 41 and adjusting the flow rate of the heat storage heat medium, the temperature of the heating medium heated by heat exchange in the hot water supply unit is, for example, 45. It can be kept below ℃. In the case of a set hot water supply temperature of about 45 ° C. or less, which is normally required in general households, the temperature of the heating medium flowing in the water pipe 5 is 45 ° C. or less. This is smaller than the temperature of the heating medium at which the scale starts to precipitate as shown in FIG. For this reason, it can suppress that a scale adheres.

  In addition, the auxiliary heat exchanger 44 reduces the temperature of the heat storage heat medium flowing out from the auxiliary heat exchanger 44 and flowing into the main heat exchanger 43 to 45 ° C. or less even during maximum heat exchange or maximum temperature hot water supply. Has the ability to For this reason, even if the hot water supply temperature is as high as 80 ° C., the temperature of the heating medium heated by the main heat exchanger 43 can be suppressed to 45 ° C. by the sub heat exchanger 44. Therefore, it is possible to suppress the scale from adhering to the flow path through which the heating medium flows in the main heat exchanger 43. Here, hot water supply at a high temperature of 80 ° C. is used less frequently. For this reason, the scale hardly adheres to the auxiliary heat exchanger 44. Therefore, the sub heat exchanger 44 can be reduced in size and extended in life.

  Further, the auxiliary heat exchanger 44 is a coil-in-tank heat exchanger. The coil-in-tank heat exchanger has high resistance to scale blockage. For this reason, it is difficult for the sub heat exchanger 44 to adhere to the scale. Even if a scale adheres to the auxiliary heat exchanger 44, the auxiliary heat exchanger 44 and the main heat exchanger 43 are separate from each other, so that only the auxiliary heat exchanger 44 can be cleaned or replaced. Therefore, maintainability is high.

  A compressor 21 that compresses the heat exchange heat medium, a supply heat exchanger 22 that exchanges heat with the heat exchange heat medium and heats the heat storage heat medium, an expansion unit 23, and a heat source heat exchanger 24 are connected by a heat pump pipe. The heat pump circulation circuit 2 is further provided. Thereby, the heat storage heat medium can be heated in the supply heat exchanger 22. Further, in the hot water supply unit 42, the flow of the heat storage heat medium and the flow of the heating medium are opposed to each other. Thereby, the heat exchange efficiency in the hot water supply unit 42 is improved.

  The heating medium is heated by exchanging heat with the heat storage heat medium. That is, the heating medium only flows through the water pipe 5 and does not flow through the first circulation circuit 3 and the second circulation circuit 4. Therefore, since the component which becomes the basis of the scale contained in a heating medium does not flow into the heat storage tank 32 and the supply heat exchanger 22, precipitation of a scale is suppressed. In addition, the water pipe 5 does not contain germs that easily propagate at low temperatures, so that the hygiene of the hot water supply can be maintained. Thereby, since sterilization work is unnecessary, temporary high temperature operation is also unnecessary. For this reason, it is not necessary to operate the heat pump device 20 carelessly. Therefore, power consumption can be reduced, which contributes to energy saving. As described above, a highly reliable heat storage water heater that is reduced in size, extended in life and resistant to high-scale blockage is realized.

  2. Description of the Related Art Conventionally, there is known a hot water supply heat exchanger that has a first heat exchanger and a second heat exchanger and heats water using exhaust gas flowing out from a fuel cell. In the conventional heat exchanger for hot water supply, since high-temperature water always flows in the water-side flow path of the first heat exchanger, scale always deposits on the first heat exchanger. For this reason, the risk of clogging due to scale adhesion is increased, and there is a risk that the heat exchanger for hot water supply is enlarged, the cost is increased, and the energy saving performance is deteriorated due to an increase in pressure loss.

  On the other hand, this Embodiment 1 is provided with the 1st circulation circuit 3 and the 2nd circulation circuit 4 to which the thermal storage tank 32 was connected. For this reason, suppression of scale adhesion and suppression of germ propagation can be achieved simultaneously. The auxiliary heat exchanger 44 is not limited to a coil-in-tank heat exchanger, but is a double-pipe heat exchanger, corrugated heat exchanger or corrugated heat exchanger whose diameter is increased by increasing the pipe diameter. It is good also as a shell and tube type heat exchanger. In the first embodiment, even if the heating medium is hard water, the temperature can be suppressed to 45 ° C. or lower, so that scale adhesion can be suppressed.

Embodiment 2. FIG.
FIG. 3 is a circuit diagram showing a heat storage water heater 100 according to Embodiment 2 of the present invention. The second embodiment is different from the first embodiment in that the sub heat exchanger 144 is a plate-type heat exchanger in the heat storage water heater 100. In the second embodiment, portions common to the first embodiment are denoted by the same reference numerals, description thereof is omitted, and differences from the first embodiment will be mainly described.

  As shown in FIG. 3, the hot water supply unit 142 includes a main heat exchanger 43 and a sub heat exchanger 144. The auxiliary heat exchanger 144 is a small and high performance plate heat exchanger, and the plate is provided with a vibrating body 145 that vibrates the plate. A plurality of plates are provided, and the plurality of plates are arranged in one direction. The vibrating body 145 is fixed to a position away from the outer edge of the plate in one of the plurality of plates in the arrangement direction. The vibrating body 145 includes a vibrator that is a piezoelectric element, and is connected to a high-frequency conductor (not shown), a high-frequency power source (not shown), and a power source (not shown).

  Next, scale generation suppression operation will be described. The scale generation suppression operation is an operation that suppresses the generation of scale when there is a possibility that scale is generated in the auxiliary heat exchanger 144. When it is detected by the flow rate detection unit 7 attached to the hot water supply path 53 of the water pipe 5 that the heating medium having a high temperature, for example, 55 ° C. or more has flowed, the control unit 10 performs the scale generation suppression operation. Is determined to start.

  In this case, the control unit 10 controls the power supply so as to apply a voltage to the vibrating body 145 and controls the high-frequency power supply so as to apply a high-frequency voltage to the vibrating body 145 via the high-frequency conductor. Thereby, the vibrating body 145 vibrates at a vibration frequency of 20 kHz which is, for example, ultrasonic vibration. Since the vibrating body 145 is attached to the plate of the sub heat exchanger 144, the sub heat exchanger 144 generates vibration that swings in the plate arrangement direction. Due to this vibration, cavitation bubbles are generated in the heating medium facing the plate surface of the auxiliary heat exchanger 144. Note that the heating medium facing the plate surface of the auxiliary heat exchanger 144 is heat exchanged with the heat storage heat medium in the main heat exchanger 43 through the water supply passage 52 and flows into the auxiliary heat exchanger 144. Cavitation bubbles collapse over time. The physical impact at the time of foam collapse removes foreign matters such as scales adhering to the plate surface, and inactivates microorganisms adhering to the plate surface.

  According to the second embodiment, the auxiliary heat exchanger 144 is a plate-type heat exchanger, and the vibrating body 145 that vibrates the plate is provided on the plate. For this reason, a foreign substance such as a scale adhering to the plate surface is removed by an impact when the foam generated by the vibration of the vibrating body 145 collapses, and microorganisms adhering to the plate surface are inactivated. For this reason, even if the auxiliary heat exchanger 144 is reduced in size and performance, the accumulation of scale can be suppressed. Further, the auxiliary heat exchanger 144 reduces the temperature of the heat storage heat medium flowing out from the auxiliary heat exchanger 144 and flowing into the main heat exchanger 43 to 45 ° C. or less even during maximum heat exchange or maximum temperature hot water supply. Has the ability to For this reason, it can suppress that a scale adheres to the main heat exchanger 43. FIG.

Embodiment 3 FIG.
FIG. 4 is a circuit diagram showing a heat storage water heater 200 according to Embodiment 3 of the present invention. The third embodiment is different from the first embodiment in that the hot water supply unit 242 includes a heating unit 244 instead of the sub heat exchanger 44 in the heat storage hot water supply apparatus 200. In the third embodiment, portions common to the first embodiment are denoted by the same reference numerals, description thereof is omitted, and differences from the first embodiment will be mainly described.

(Hot water supply unit 242)
As shown in FIG. 4, the hot water supply unit 242 includes a main heat exchanger 43 and a heating unit 244. The main heat exchanger 43 is provided on the upstream side of the heat storage tank 32 in the second circulation circuit 4, and heats the heating medium by exchanging heat with the heat storage heat medium. This is the same as the container 43. The heating unit 244 further heats the heating medium heat exchanged with the heat storage heat medium in the main heat exchanger 43, and is connected to the hot water supply path 53 of the water pipe 5. The heating unit 244 is a throwing-type electric heater that is thrown into the heating medium and directly heated. The heating unit 244 is connected to a power source (not shown).

(Water pipe 5)
The water pipe 5 is a channel through which a heating medium flows, and has a water supply channel 52 and a hot water supply channel 53 that connect the water supply source 51 and the hot water supply unit 54. The water supply source 51 is a supply source of the heating medium, and the hot water supply unit 54 is a hot water supply destination of the heating medium. The water supply path 52 connects the water supply source 51 and the main heat exchanger 43 of the hot water supply unit 242. The hot water supply path 53 connects the heating unit 244 and the hot water supply unit 54 of the hot water supply unit 242. The heating medium is, for example, tap water, flows from the water supply source 51 through the water supply path 52 of the water pipe 5, flows into the hot water supply unit 242, flows out of the hot water supply unit 242, and then passes through the hot water supply path 53 of the water pipe 5. To the hot water supply unit 54. Thus, in the hot water supply unit 242, the flow of the heat storage heat medium flowing in the second circulation circuit 4 and the flow of the heating medium flowing in the water pipe 5 are opposed to each other.

(Flow of heat storage heat storage in the second circulation circuit 4)
Next, the flow of the heat storage heat medium in the second circulation circuit 4 will be described. The flow of the heat exchange heat medium in the heat pump circulation circuit 2 and the flow of the heat storage heat medium in the first circulation circuit 3 are the same as those in the first embodiment. In the second circulation circuit 4, the heat storage heat medium supplied by the second water supply unit 41 passes from the lower part of the heat storage tank 32 to the inside of the heat storage tank 32 through the second return path 40 b of the second pipe 40. It flows in and is stored in the heat storage tank 32. The high-temperature heat storage heat medium stored above the heat storage tank 32 flows out from the upper part of the heat storage tank 32 to the second forward path 40 a of the second pipe 40. The heat storage heat medium that has flowed out flows into the main heat exchanger 43 of the hot water supply unit 242 through the second forward path 40a of the second pipe 40, and in the main heat exchanger 43, the heat medium that flows into the water pipe 5 and Heat exchanged and cooled. At this time, the heating medium is heated. The cooled heat storage heat storage medium returns to the second water supply unit 41 again. Thus, the heat storage heat medium circulates through the second circulation circuit 4.

(Flow of heating medium in water pipe 5)
Next, the flow of the heating medium in the water pipe 5 will be described. The heating medium supplied from the water supply source 51 flows into the main heat exchanger 43 of the hot water supply unit 242 through the water supply path 52, and the heat storage heat medium flowing into the second circulation circuit 4 in the main heat exchanger 43. Heat is exchanged with. Thereafter, the heated heating medium flows into the heating unit 244 of the hot water supply unit 242, and is further heated in the heating unit 244. The heated heating medium passes through the hot water supply path 53 and reaches the hot water supply section 54.

(Heat storage operation)
Next, the heat storage operation will be described. In the heat storage operation, the temperature of the heat storage heat medium stored in the heat storage tank 32 is different from the first embodiment in that the temperature at which the scale easily precipitates is, for example, 55 ° C. or less, and the others are the same as in the first embodiment. It is.

(Hot water operation)
Next, the hot water supply operation will be described. First, the case where the temperature of the heating medium supplied from the water supply path 52 is 20 ° C. and the set hot water supply temperature is 45 ° C., for example, will be described. The low temperature, for example, 20 ° C. heating medium supplied from the water supply source 51 flows into the main heat exchanger 43 through the hot water supply passage 53 of the water pipe 5, and flows into the second circulation circuit 4 in the main heat exchanger 43. The temperature is increased from 20 ° C. to 45 ° C. by heat exchange with the heat storage heat medium. The heating medium heated to 45 ° C. is supplied with hot water to the hot water supply section 54 through the hot water supply passage 53.

  Next, the case where the temperature of the heating medium supplied from the water supply channel 52 is 20 ° C., for example, and the set hot water supply temperature is 55 ° C. or higher, for example, 80 ° C. will be described. When the set hot water supply temperature is higher than the temperature of the heat storage heat medium stored in the heat storage tank 32, such as 80 ° C., the control unit 10 controls the power supply so as to apply a voltage to the heating unit 244. The low temperature, for example, 20 ° C. heating medium supplied from the water supply source 51 flows into the main heat exchanger 43 through the hot water supply passage 53 of the water pipe 5, and flows into the second circulation circuit 4 in the main heat exchanger 43. Heat is exchanged with the heat storage heat medium, and the temperature rises from 20 ° C to 45 ° C. And a heating medium flows in into the heating part 244, is heated by the heating part 244, and temperature rises to 80 degreeC. The heating medium heated to 80 ° C. is supplied with hot water to the hot water supply section 54 through the hot water supply passage 53.

  According to the third embodiment, the temperature of the heat storage heat medium stored in the heat storage tank 32 can be suppressed to a temperature at which the scale hardly precipitates. For this reason, power, such as a load of the heat pump device 20, for heating the heat storage heat medium can be suppressed. Further, when the temperature of the heat storage heat medium stored in the heat storage tank 32 is low, the influence of heat radiation from the heat storage tank 32 is low. For this reason, the level of heat insulation applied to the heat storage tank 32 can be lowered.

  Moreover, when the temperature of the heat storage heat medium stored in the heat storage tank 32 is low, the temperature at which the heating medium is heated is also low. For this reason, it can suppress that a scale adheres to the flow path through which a heating medium flows in the main heat exchanger 43. The heating medium is heated by exchanging heat with the heat storage heat medium. That is, the heating medium only flows through the water pipe 5 and does not flow through the first circulation circuit 3 and the second circulation circuit 4. Therefore, since the component which becomes the basis of the scale contained in a heating medium does not flow into the heat storage tank 32 and the supply heat exchanger 22, precipitation of a scale is suppressed. In addition, the water pipe 5 does not contain germs that easily propagate at low temperatures, so that the hygiene of the hot water supply can be maintained. Thereby, since sterilization work is unnecessary, temporary high temperature operation is also unnecessary. For this reason, it is not necessary to operate the heat pump device 20 carelessly, and it is not necessary to operate the heating unit 244 carelessly. Therefore, power consumption can be reduced, which contributes to energy saving.

  In addition, although illustrated about the case where the heating part 244 is an electric heater, not only this but the heating part 244 may be a combustor by a combustible medium.

  In the first to third embodiments, the heat storage heat medium is an antifreeze liquid, but may be water. In this case, it is necessary to control the temperature of the water so that it does not freeze. Moreover, the latent heat storage body may be accommodated in the heat storage tank 32 together with the heat storage heat medium. The latent heat storage body is a container in which a latent heat storage material is hermetically housed, and is, for example, a hollow spherical container or a hollow flat container. The latent heat storage material solidifies and melts within the operating temperature range of the heat storage heat medium, and is, for example, paraffin or sodium acetate hydrate. The heat storage tank 32 in which the latent heat storage body is accommodated can suppress the heat storage volume while maintaining a predetermined heat storage amount. For this reason, the heat storage tank 32 can be reduced in size, or the heat storage amount can be increased with the same heat storage volume. In addition, although Embodiment 1-3 has illustrated about the thermal storage water heater 200, it is good also as a thermal storage hot water supply air conditioner.

  DESCRIPTION OF SYMBOLS 1 Heat storage water heater, 2 Heat pump circulation circuit, 3 1st circulation circuit, 4 2nd circulation circuit, 5 Water piping, 6 Temperature detection part, 7 Flow volume detection part, 10 Control part, 20 Heat pump apparatus, 21 Compressor, 22 Supply heat exchanger, 23 Expansion part, 24 Heat source heat exchanger, 25 Outside air blower, 30 1st piping, 30a 1st outgoing path, 30b 1st return path, 31 1st water supply part, 32 Heat storage tank, 40 2nd Piping, 40a Second outgoing path, 40b Second return path, 41 Second water supply section, 42 Hot water supply unit, 43 Main heat exchanger, 44 Sub heat exchanger, 51 Water supply source, 52 Water supply path, 53 Hot water supply path, 54 Hot water supply Part, 100 heat storage hot water supply machine, 142 hot water supply unit, 144 auxiliary heat exchanger, 145 vibrator, 200 heat storage water heater, 242 hot water supply unit, 244 heating part.

Claims (11)

A first water supply section for supplying the heat storage heat medium, a supply heat exchanger for heating the heat storage heat medium supplied by the first water supply section, and a heat storage tank for storing the heat storage heat medium. A first circulation circuit connected by a first pipe;
Heat exchange is performed by exchanging heat with the second water supply unit that supplies the heat storage heat medium stored in the heat storage tank, the heat storage tank, and the heat storage heat medium supplied by the second water supply unit. A hot water supply unit to be heated and a second circulation circuit connected by a second pipe,
The hot water supply unit is
A main heat exchanger for heating the heating medium;
A sub heat exchanger that is provided upstream of the main heat exchanger in the second circulation circuit and that heats the heating medium heat exchanged with the heat storage heat medium in the main heat exchanger;
Heat storage water heater having. The auxiliary heat exchanger is
The heat storage water heater according to claim 1, wherein the heat storage water heater is a coil-in-tank heat exchanger. The auxiliary heat exchanger is
A plate-type heat exchanger,
The heat storage water heater according to claim 1, wherein the plate is provided with a vibrating body that vibrates the plate. The auxiliary heat exchanger is
The heat storage hot-water supply apparatus of any one of Claims 1-3 which has the capability to reduce the temperature of the said thermal storage heat medium which flows into the said main heat exchanger to 45 degrees C or less. A first water supply section for supplying the heat storage heat medium, a supply heat exchanger for heating the heat storage heat medium supplied by the first water supply section, and a heat storage tank for storing the heat storage heat medium. A first circulation circuit connected by a first pipe;
A second circulation circuit in which the second water supply section for supplying the heat storage heat medium stored in the heat storage tank, the heat storage tank, and a hot water supply unit for heating the heating medium are connected by a second pipe; With
The hot water supply unit is
A main heat exchanger that heats the heating medium by exchanging heat with the heat storage heat medium fed by the second water feeding section;
A heating unit that heats the heating medium heat-exchanged with the heat storage heat medium in the main heat exchanger;
Heat storage water heater having. The heat storage water heater according to claim 5, wherein the heating unit is an electric heater. The heat storage water heater according to claim 5, wherein the heating unit is a combustor. The compressor that compresses the heat exchange heat medium, the supply heat exchanger that exchanges heat with the heat exchange heat medium to heat the heat storage heat medium, the expansion unit, and the heat source heat exchanger are connected by a heat pump pipe. The heat storage hot water supply device according to any one of claims 1 to 7, further comprising a heat pump circulation circuit. The heat storage hot water supply device according to any one of claims 1 to 8, wherein in the hot water supply unit, the flow of the heat storage heat medium and the flow of the heating medium are opposed to each other. The heat storage hot water supply apparatus according to any one of claims 1 to 9, wherein a temperature of the heat storage heat medium is 55 ° C or lower. The heat storage hot water supply apparatus according to any one of claims 1 to 10, wherein the heating medium is hard water.

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