JP2013200078A - Hot water storage heating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water storage heating apparatus capable of lowering a temperature of hot water flowing in a hot water circulation circuit without requiring a dedicated water discharge passage and water discharge on-off valve.SOLUTION: A hot water storage heating apparatus 1 includes: a hot water storage tank 41; an external heat source 2 for heating hot water in the hot water storage tank 41; a hot water circulation circuit 45 circulating hot water between the external heat source 2 and the hot water storage tank 41; and a hot water heating circuit 48 having an expansion tank 80 capable of storing heating water heated via heat storage in the hot water storage tank 41. The hot water storage heating apparatus 1 includes: a replenishing passage 95 having a lower end connected to the expansion tank 80 to supply the heating water to the expansion tank 80; an on-off valve 96 installed in the replenishing passage 95; and a control means 97 switching an opening/closing state of the on-off valve 95. An upper end of the replenishing passage 95 is branched and connected to a return side passage of the hot water circulation circuit 45, and hot water flowing in the hot water circulation passage 45 can be supplied to the expansion tank 80 via the replenishing passage 95.

Description

  The present invention relates to a hot water storage and heating device, and more particularly to a hot water storage device that can supply hot hot water flowing through a hot water circulation circuit to an expansion tank of a hot water heating circuit without returning to the hot water storage tank when the hot water storage tank is fully charged.

  Conventionally, a fuel cell core that generates air by supplying air and a reformed fuel gas (hydrogen-containing gas) to the fuel cell stack, and recovers the heat generated secondaryly during the power generation as hot water. Generation systems are in practical use. The fuel cell cogeneration system includes a power generation unit that generates power, and a hot water storage and heating unit that includes a hot water storage tank that stores hot water after heat exchange is performed between exhaust gas discharged from the power generation unit. It is generally used as a heating device.

  The power generation unit generally includes a fuel cell stack that generates power with air and reformed fuel gas, and reformed fuel gas supplied to the fuel cell stack from pure water (water vapor) and a fuel gas such as natural gas. A reformer to be generated, a heat exchanger for exchanging heat between the exhaust gas from the fuel cell stack and hot water in the hot water storage tank, a storage tank for storing pure water to be supplied to the reformer, and the like. .

  In addition to the hot water storage tank described above, the hot water storage / heating unit supplies hot water circulating between the power generation unit and the hot water storage tank, and supplies hot water stored in the hot water storage tank to a desired hot water supply destination such as a bath. Hot water supply circuit, hot water heating circuit that supplies heating water to floor heating panels, etc. A use circuit is provided.

  By the way, in the power generation unit described above, so-called water self-sustained operation is performed in which water is recovered from the exhaust gas from the fuel cell stack and reused. Normally, hot water in the hot water storage tank is circulated in the hot water circulation circuit, heat is exchanged between the hot water and the exhaust gas in the heat exchanger of the power generation unit, and the water vapor contained in the exhaust gas is cooled to condense the condensed water. Collected.

  However, the temperature of hot water flowing from the hot water storage tank to the heat exchanger through the hot water circulation circuit rises due to the heat storage status of the hot water storage tank, and eventually the hot water storage tank becomes fully stored (a state where the hot water is full). The hot water circulating in the hot water circulation circuit reaches a temperature above the dew point in the heat exchanger. As a result, the amount of condensed water generated in the heat exchanger decreases and a sufficient amount of condensed water cannot be recovered, and the supply of reforming water may be insufficient.

  In such a case, in the fuel cell system disclosed in Patent Document 1, by operating a radiator provided in the hot water circulation circuit, the temperature of the hot water supplied to the heat exchanger is lowered and the condensed water is recovered. When a radiator is not installed, the hot water in the return pipe of the hot water circulation circuit is drained directly to the outside through the drainage passage where the on-off valve is installed, and new low-temperature clean water is supplied to the hot water storage tank. The temperature of the hot water circulating in the hot water circulation circuit is lowered.

JP 2010-277773 A

  However, in the structure in which the radiator of Patent Document 1 is not installed, a dedicated drainage passage and drainage on-off valve for draining hot hot water from the hot water circulation circuit to the outside are required, resulting in high costs. In addition, before returning the hot water heated by the heat exchanger to the upper part of the hot water storage tank, the upper side of the hot water storage tank is structured by draining the water from the return side piping to the outside due to the supply water pressure supplied with the hot water drainage. Therefore, hot hot water may be drained to the outside through the return side piping, and the hot water storage state in the hot water storage tank is not stable. For this reason, even if low temperature clean water is supplied from the water supply source to the lower part of the hot water storage tank, it does not flow smoothly to the piping on the outgoing side of the hot water circulation circuit, and mixes with hot water on the high temperature side in the hot water storage tank. Hot water is supplied to the hot water circulation circuit, and the efficiency of condensate recovery decreases.

  On the other hand, when a radiator is installed, the radiator is generally complicated and expensive, which is disadvantageous in reducing the manufacturing cost and downsizing the device. Although a small size is desirable, there is a possibility that a sufficient amount of condensed water cannot be recovered with a small radiator when the outside air temperature is high in summer or the like.

  Furthermore, in the fuel cell cogeneration system, a circulation pump for circulating hot water in the hot water circulation passage is provided in the power generation unit (or hot water storage / heating unit). However, since the hot water circulation circuit is configured in a closed circuit, When the air venting operation is performed, it is necessary to vent the hot water circulation circuit by drawing water into the circulation pump and driving the circulation pump.

  An object of the present invention is to provide a hot water storage / heating device capable of lowering the temperature of hot water flowing through a hot water circulation circuit without requiring a dedicated drainage passage or a drain on / off valve, and a circulation pump at the time of air venting operation. To provide a hot water storage / heating device capable of bleeding the hot water circulation circuit without being operated.

  The hot water storage and heating device according to claim 1 includes a hot water storage tank, an external heat source for heating hot water in the hot water storage tank, a hot water circulation circuit for circulating hot water between the external heat source and the hot water storage tank, and at least the hot water storage. A hot water storage and heating apparatus comprising a hot water heating circuit having an expansion tank capable of storing heating water heated through heat storage in the tank, wherein a downstream end is connected to the expansion tank and the heating water is supplied to the expansion tank A replenishment passage, an on-off valve provided in the replenishment passage, and a control means for switching the open / close state of the on-off valve, the upstream end of the replenishment passage being branched and connected to the return side passage of the hot water circulation circuit The hot water flowing through the hot water circulation circuit can be supplied to the expansion tank through the supply passage.

  The hot water storage / heating device of claim 2 is characterized in that, in the invention of claim 1, a check valve is provided in the return side passage of the hot water circulation circuit downstream from the branch portion where the supply passage branches. .

  According to a third aspect of the present invention, there is provided the hot water storage / heating apparatus according to the first or second aspect, wherein the control means controls the on-off valve when the temperature of the hot water in the forward passage of the hot water circulation circuit becomes equal to or higher than a predetermined temperature. It is characterized by opening.

  According to a fourth aspect of the present invention, there is provided the hot water storage / heating apparatus according to any one of the first to third aspects, wherein the control means opens the on-off valve during an air bleeding operation.

  According to the first aspect of the present invention, the upstream end of the replenishment passage is branched and connected to the return side passage of the hot water circulation circuit so that hot water flowing through the hot water circulation circuit can be supplied to the expansion tank via the replenishment passage. If you want to drain the hot water flowing through the return side piping of the circulation circuit, or if you want to replenish the heating water to the expansion tank, open the on-off valve to heat the hot water through the supply passage. It can be drained or supplied to the expansion tank of the circuit. Therefore, the existing replenishment passage and opening / closing valve for replenishing heating water are shared for the drainage of hot water from the hot water circulation circuit. This eliminates the need to install a drainage passage and a drainage on-off valve, thereby reducing costs.

  According to the second aspect of the present invention, in the return side passage of the hot water circulation circuit, the check valve is provided downstream from the branching portion where the replenishment passage branches. The hot water in the hot water storage tank does not move, and the hot water in the hot water tank does not move and maintains a stable state. Therefore, low temperature clean water can be reliably supplied to the forward passage of the hot water circulation circuit via the lower part of the hot water tank, and the hot water flowing through the hot water circulation circuit The temperature of can be greatly reduced.

  According to the invention of claim 3, the control means opens the on-off valve when the temperature of the hot water in the outward passage of the hot water circulation circuit is equal to or higher than a predetermined temperature, so that the hot water storage tank is fully charged. In such a case, hot hot water in the hot water circulation circuit can be drained to the expansion tank through the supply passage. For this reason, it is possible to newly introduce low temperature clean water into the hot water circulation circuit via the hot water storage tank, and it is not necessary to provide an expensive and large-sized radiator in the hot water circulation circuit, thereby making it possible to reduce manufacturing costs and operation costs.

  According to the invention of claim 4, since the control means opens the on-off valve during the air bleeding operation, the hot water circulation circuit can be vented by the supply water pressure of the water supply source, and the time for the air bleeding operation can be shortened. Can be planned.

It is a schematic block diagram of the hot water storage heating unit of the hot water storage heating apparatus which concerns on Example 1 of this invention. It is a schematic block diagram of a power generation unit. It is a schematic block diagram of the hot water storage and heating unit of the hot water storage and heating device during the exhaust heat discharge operation. It is a schematic block diagram of the hot water storage and heating unit of the hot water storage and heating device during hot water discharge operation.

  Hereinafter, modes for carrying out the present invention will be described based on examples.

First, the whole structure of the hot water storage / heating device 1 of the present invention will be described.
As shown in FIGS. 1 and 2, a hot water storage and heating device 1 includes a power generation unit 2 that generates electric power, a hot water storage tank 41 that stores hot water after heat exchange, and a hot water circulation circuit 45 that circulates the hot water. This is a fuel cell cogeneration system including a heating unit 3.

  As shown in FIG. 2, the power generation unit 2 is an external heat source of the hot water storage / heating unit 3 for heating the hot water in the hot water storage tank 41, and includes a fuel cell power generation module 4, a cathode air blower 5, and a fuel gas booster blower. The apparatus 6 includes a fuel reforming air blower 7, an exhaust gas discharge passage 8, a heat exchanger 9, a water treatment device 11, an inverter 12, and the like.

  The power generation unit 2 is configured such that the above-described various devices are integrally housed in an outer case 13, and the DC power generated by the fuel cell power generation module 4 is converted into AC power via the inverter 12 to the outside. Is output. The power generation unit 2 is provided with a plurality of temperature sensors including an outside air temperature sensor 14 that can detect the outside air temperature installed in the outer case 13, but detailed description thereof is omitted.

  The air blower 5 for cathode air takes air from the outside into the power generation air blower 5b through the filter 5a, and this taken air is supplied to the air passage 15 in which the buffer tank 15a, the flow sensor 15b, and the check valve 15c are installed. Is supplied to the fuel cell power generation module 4.

  The blower 6 for boosting the fuel gas takes in the fuel gas from a gas supply source (not shown) through the solenoid valve 6a and the gas governor 6b into the fuel booster blower 6c, and the boosted fuel gas is desulfurized with the buffer tank 16a, the flow sensor 16b, and the like. The fuel cell power generation module 4 is supplied through the gas passage 16 in which the vessel 16c is installed and the common passage 18 in which the check valve 18a is installed.

  The fuel reforming air blower 7 takes in the fuel reforming air from the outside to the reforming air blower 7b through the filter 7a, and the taken fuel reforming air is supplied to the flow sensor 17a and the solenoid valve. The fuel cell power generation module 4 is supplied through a reformed air passage 17 and a common passage 18 in which a check valve 17c and a check valve 17c are installed.

Next, the fuel cell power generation module 4 will be described.
As shown in FIG. 2, the fuel cell power generation module 4 (hereinafter referred to as the power generation module 4) includes a fuel cell stack 21, an evaporator 22, a fuel reformer 23, an off-gas combustion chamber 24, a heat exchanger 27, and the like. The fuel cell stack 21 causes a chemical reaction between the reformed fuel gas reformed by the fuel reformer 23 and air as an oxidant.

  The evaporator 22 generates steam for mixing with the fuel gas and supplies it to the fuel reformer 23. The evaporator 22 has a fuel gas (city gas, LPG, etc.) taken in and boosted by the fuel gas boosting blower 6, and fuel reforming air taken in by the fuel reforming air blower 7. However, pure water is supplied from the water treatment device 11 via the pure water passage 35. The evaporator 22 generates water vapor from the supplied pure water.

  The fuel reformer 23 includes a reforming catalyst such as platinum in the inside thereof, and reacts by mixing fuel gas, air, and steam supplied from the evaporator 22 via the mixing passage 25 (so-called steam reforming). Thus, the hydrogen-rich reformed fuel gas is generated, and this reformed fuel gas is supplied to the fuel electrode side of the fuel cell stack 21 via the reformed fuel gas supply path 26.

  The fuel cell stack 21 is configured by arranging a plurality of fuel cells. Each fuel cell is formed of a solid electrolyte such as zirconia, a fuel electrode, and an oxygen electrode. The reformed fuel gas is supplied from the fuel reformer 23 to the fuel electrode (anode) side of the fuel cell stack 21, and the cathode air blower 5 is supplied to the oxygen electrode (cathode) side of the fuel cell stack 21. From the air passage 15 and the heat exchanger 27 heated by the exhaust gas, air is supplied, and these are electrochemically reacted in a high temperature environment to generate DC power.

  The off-gas combustion chamber 24 is for burning the remaining fuel gas generated by the power generation of the fuel cell stack 21 and is connected to the fuel electrode side and the oxygen electrode side discharge sides of the fuel cell stack 21. Yes. In this off-gas combustion chamber 24, a high temperature is obtained by burning a reaction fuel gas containing residual fuel gas discharged from the fuel electrode side and air containing oxygen discharged from the oxygen electrode side using a known combustion catalyst. Exhaust gas is generated, the fuel reformer 23 and the heat exchanger 9 are heated with the exhaust gas, and then discharged to the outside through the exhaust gas discharge passage 8.

  The heat exchanger 9 is provided in the middle of the exhaust gas discharge passage 8 and includes a heat exchange passage portion 9 a that constitutes a part of the hot water circulation circuit 45. In this heat exchanger 9, the exhaust gas discharged from the power generation module 4 is heat-exchanged with hot water flowing through the heat exchange passage 9a, and the water vapor contained in the exhaust gas is cooled and condensed to be condensed water. It becomes.

Next, the water treatment device 11 will be described.
As shown in FIG. 2, the water treatment apparatus 11 includes a treatment tank 31, a pure water tank 32, a pure water pump 33, and the like, and condensate water condensed in the heat exchanger 9 is passed through a recovery passage 34. Then, the water from which impurities are removed by the processing tank 31 is supplied to the evaporator 22 of the power generation module 4 through the pure water passage 35.

  The processing tank 31 is for removing impurities of condensed water recovered from the heat exchanger 9. The treatment tank 31 is provided with an ion exchange resin that removes impurities contained in the condensed water by ion exchange. A recovery passage 34 is connected to the upper portion of the processing tank 31. An overflow drainage passage 37 a is connected to the upper portion of the processing tank 31. A neutralizer 38 is installed in the drainage passage 37a.

  The pure water tank 32 is for temporarily storing the water processed by the processing tank 31. A tank connection passage 36 connected to the lower part of the processing tank 31 is connected to the upper part of the pure water tank 32. Overflow drainage passages 37b and 37c are connected to a middle portion of the tank connection passage 36 and an upper portion of the pure water tank 32, respectively.

  The pure water tank 32 is provided with a water level switch 39 that can detect the level of pure water stored in the pure water tank 32 according to three levels (upper level L1, middle level L2, and lower level L3). ing. The pure water recovery operation mode (exhaust heat recovery operation / exhaust heat discharge operation / hot water discharge operation) is switched according to the level of pure water detected by the water level switch 39.

  A pure water passage 35 is connected to a lower end portion of the pure water tank 32, and a pure water pump 33, a flow rate sensor 35a, and a check valve 35b are sequentially installed in the middle of the pure water passage 35. The pure water pump 33 is for supplying the purified water in the pure water tank 32 to the evaporator 22 of the power generation module 4. By driving the pure water pump 33, pure water is supplied to the evaporator 22 through the pure water passage 35.

Next, the hot water storage / heating unit 3 will be described.
As shown in FIG. 1, the hot water storage / heating unit 3 has functions such as hot water supply, supply of heat to the floor heating panel, reheating of the bath, etc., and includes a hot water storage tank 41, an auxiliary heat source unit 42, first and first heating units. 2 heat exchangers 43 and 44, hot water circulation circuit 45, water supply circuit 46, hot water supply circuit 47, hot water heating circuit 48, bath hot water supply circuit 49, heat utilization circulation circuit 50, and a plurality of these circuits 45 to 50 connected to each other The bypass passages 51 to 54, 57, the bath hot water passage 55, the hot water passage 58, and the like are integrally housed in the exterior case 59.

  The hot water storage tank 41 is a heat-insulating hermetically long tank that can store hot hot water (for example, 80 to 90 ° C.) and is elongated in the vertical direction, and the tank periphery is covered with a heat insulating material to prevent heat dissipation of the stored hot water. ing. The temperature of the hot water in the plurality of reservoirs in the hot water storage tank 41 is detected by the plurality of tank hot water temperature sensors 61a to 61d.

  The auxiliary heat source unit 42 is composed of a known gas water heater with a built-in burner 42a, a heat exchanger 42b, etc., and reheats the hot water only in special cases such as when the temperature of the hot water in the heat utilization circulation circuit 50 is insufficient. To do.

  The first heat exchanger 43 heats the heating water flowing through the hot water heating circuit 48, and the heat exchange passage portion 43 a that becomes a part of the heat utilization circulation circuit 50 and the heat that becomes a part of the hot water heating circuit 48. And an exchange passage portion 43b. In the first heat exchanger 43, heat is exchanged between hot hot water flowing through the heat utilization circulation circuit 50 and heating water flowing through the hot water heating circuit 48, and the heating water is heated and the hot water is cooled.

  The second heat exchanger 44 heats the hot water in the bath that flows through the bath hot water supply circuit 49, and includes a heat exchange passage 44 a that forms part of the heat utilization circuit 50 and the bath hot water supply circuit 49. It has a part of the internal space 44b. In the second heat exchanger 44, heat is exchanged between hot hot water flowing through the heat utilization circuit 50 and bath water flowing through the bath hot water supply circuit 49, and the bath water is heated and the hot water is cooled.

Next, the hot water circulation circuit 45 will be described.
As shown in FIGS. 1 and 2, the hot water circulation circuit 45 is a closed circuit that circulates hot water between the heat exchanger 9 of the power generation unit 2 that is an external heat source and the hot water storage tank 41, and includes an upstream forward passage 45a. A downstream return side passage 45b, an upstream return side passage 45c, and a downstream return side passage 45d. The upstream end of the upstream forward side passage 45a is connected to the lower part of the hot water storage tank 41, and the downstream return side passage is connected to the upper part of the hot water storage tank 41. The downstream end of 45d is connected.

  A first bypass passage 51 connected between the upstream return side passage 45c and the downstream return side passage 45d is branched from between the upstream forward side passage 45a and the downstream forward side passage 45b. A hot water storage switching valve 62 is provided that can alternatively select connection between the passage 45a and the downstream forward passage 45b or connection between the downstream forward passage 45b and the first bypass passage 51. A radiator 63 capable of rapidly cooling the hot and cold water is installed in the downstream outward passage 45b. An exhaust heat recovery circulation pump 64 (see FIG. 2) is installed on the power generation unit 2 side of the downstream forward passage 45b.

  A heat exchange passage portion 9a of the heat exchanger 9 of the power generation unit 2 is connected between the downstream forward passage 45b and the upstream return passage 45c. In the downstream return side passage 45d of the hot water circulation circuit 45, a check valve 65 that allows the flow toward the hot water storage tank 41 is provided downstream of a branching portion 45e where a replenishment passage 95 to be described later branches.

  The temperatures of hot water circulating in the hot water circulation circuit 45 are as follows: a circulating hot water temperature sensor 66a on the radiator inlet side, a circulating hot water temperature sensor 66b on the radiator outlet side, a circulating hot water temperature sensor 66c on the heat exchanger inlet side, and a heat exchanger outlet side. The temperature is detected by a circulating hot water temperature sensor 66d and a circulating hot water temperature sensor 66e in the upstream return side passage 45c. The hot water storage and heating unit 3 is provided with various temperature sensors in addition to the tank hot water temperature sensors 61a to 61d and the circulating hot water temperature sensors 66a to 66e, but detailed description thereof is omitted.

  In a normal exhaust heat recovery operation, as shown in FIG. 1, the hot water storage switching valve 62 is switched to connect the upstream forward passage 45a and the downstream forward passage 45b, and the exhaust heat recovery circulation pump 64 from the hot water storage tank 41 is switched. The hot water passes through the upstream outgoing side passage 45a and the downstream outgoing side passage 45b, is sent to the heat exchange passage portion 9a of the heat exchanger 9 and heated, and the heated hot water returns to the upstream return side passage 45c and the downstream return. It returns to the hot water storage tank 41 through the side passage 45d.

Next, the water supply circuit 46 will be described.
The water supply circuit 46 supplies low temperature clean water from a water supply source to the hot water storage tank 41, and has an upstream water supply passage 46a, an intermediate water supply passage 46b, and a downstream water supply passage 46c. The water supply source is upstream of the upstream water supply passage 46a. The end is connected, and the downstream end of the downstream water supply passage 46 c is connected to the lower part of the hot water storage tank 41. A pressure reducing valve 67 is installed in the upstream water supply passage 46a, and a check valve 46d is installed in the intermediate water supply passage 46b. A drainage passage 68 provided with a safety valve 68 a is connected to the intermediate water supply passage 46 b, and a downstream end of the drainage passage 68 extends to a drainage basin 69.

  In the water supply circuit 46, a second bypass passage 52 connected to the heat utilization circuit 50 is branched from between the intermediate water supply passage 46b and the downstream water supply passage 46c, and the intermediate water supply passage 46b and the downstream water supply passage 46c are branched to this branch portion. Or a heat storage switching valve 71 is provided which can select connection between the intermediate water supply passage 46b and the second bypass passage 52 or connection between the second bypass passage 52 and the downstream water supply passage 46c. By this second bypass passage 52, low temperature clean water can be supplied to the heat utilization circuit 50, and conversely, hot water can be returned from the heat utilization circuit 50 to the hot water storage tank 41. A drainage passage 72 connected to the outside is branched from the downstream water supply passage 46c.

Next, the hot water supply circuit 47 will be described.
The hot-water supply circuit 47 supplies hot water stored in the hot-water storage tank 41 to a desired hot-water supply destination such as a bath. The upstream end of the upstream hot water supply passage 47a is connected to the upper part of the hot water storage tank 41, and the hot water tap 73 is connected to the downstream end of the downstream hot water supply passage 47b. A mixing valve 74 is installed between the upstream hot water supply passage 47a and the downstream hot water supply passage 47b, and a third bypass passage 53 branched from the upstream water supply passage 46a is connected to the mixing valve 74. In the mixing valve 74, the flow ratio of water and hot hot water is controlled so that the tapping temperature becomes the command temperature.

  A check valve 53 a is installed in the third bypass passage 53. A fourth bypass passage 54 is directly branched from the third bypass passage 53 to the downstream hot water supply passage 47b without passing through the mixing valve 74, and a high temperature avoidance electromagnetic valve 78 is installed in the fourth bypass passage 54. By the fourth bypass passage 54, low temperature clean water can be directly supplied from the clean water source to the downstream hot water supply passage 47b.

  A flow rate sensor 47c is installed in the downstream hot water supply passage 47b, and a bath outlet hot water passage 55 connected to the bath hot water supply circuit 49 from the middle of the downstream hot water supply passage 47b on the downstream side of the flow rate sensor 47c is branched. A hot water proportional valve 75 is installed in the section. A flow sensor 55a, a pouring electromagnetic valve 76, and a check valve 55b are integrally installed in the bath outlet passage 55 in this order.

Next, the hot water heating circuit 48 will be described.
The hot water heating circuit 48 is a circuit that circulates heating water supplied to a floor heating panel, a bathroom dryer, and the like, and includes an expansion tank 80, a heating forward common passage 48a, a heating outgoing hot passage 48b, and a heating outgoing cold passage. 48c and a heating return side passage 48d.

  The expansion tank 80 can store the heating water heated via the heat storage of the hot water storage tank 41, and can allow the volume expansion of the heating water due to heating. The expansion tank 80 is provided with a pair of water level sensors 80a and 80b capable of detecting the lower limit level L and the upper limit level H of the level of the heating water. When the water level sensor 80a detects a lack of heating water, it opens and closes. By opening the valve 96, hot water can be replenished as heating water to the expansion tank 80 via the supply passage 95. Further, a drainage passage 81 is connected to the expansion tank 80, and the heating water drained from the drainage passage 81 is drained to a drainage basin 69 through a hopper 81a.

  A heating circulation pump 82 is installed in the heating outgoing common passage 48a. A heat exchange passage portion 43b of the first heat exchanger 43 is interposed in the heating going side high temperature passage 48b. A fifth bypass passage 57 connected from the heating going-side high temperature passage 48 b to the heating going-side low temperature passage 48 c is branched, and a check valve 57 a is installed in the fifth bypass passage 57. A flow control valve 83 is installed in the heating-out side low-temperature passage 48c. The heating-out side high-temperature passage 48b supplies high-temperature heating water to a bathroom dryer or the like, and the heating-out side low-temperature passage 48c supplies low-temperature heating water to a floor heating panel or the like.

  Heating water from the expansion tank 80 via the heating circulation pump 82 passes through the heating-out side common passage 48a and the heating-out side high-temperature passage 48b, is sent to the heat exchange passage portion 43b, and is heated. While being sent out to the bathroom dryer etc. from the heating going side high temperature passage 48b, the heating water is sent out to the floor heating panel etc. without being heated from the heating going side low temperature passage 48c. The heated heating water is returned to the expansion tank 80 through the heating return side passage 48d.

Next, the bath hot water supply circuit 49 will be described.
The bath hot water supply circuit 49 is a circuit for chasing hot water in the bath, and includes a bath going-out side passage 49a and a bath return side passage 49b. An internal space 44b of the second heat exchanger 44 is connected between the bath going-side passage 49a and the bath return-side passage 49b, and a bath water flow switch 84, a bath circulation pump 85, etc. is set up.

  Hot water is sent from the bath via the bath circulation pump 85 through the bath return side passage 49b and sent to the internal space 44b and heated, and the heated hot water is sent out from the bath going side passage 49a to the bath. If necessary, hot water can be replenished to the bath return side passage 49b through the bath hot water passage 55 branched from the hot water supply circuit 47.

Next, the heat utilization circulation circuit 50 will be described.
The heat utilization circulation circuit 50 is a closed circuit that circulates hot hot water in the hot water storage tank 41 and exchanges heat with the hot water heating circuit 48 and the bath hot water supply circuit 49. The hot water supply passage 50a and the auxiliary heat source go out. The hot water supply passage 50a is connected to the upper portion of the hot water storage tank 41. The hot water supply passage 50a has a side passage 50b, a heat exchange forward passage 50c, and a hot water return passage 50d.

  A three-way valve 86 is installed at the junction between the downstream end of the hot water supply passage 50a, the upstream end of the auxiliary heat source forward passage 50b, and the downstream end of the hot water return side passage 50d. The three-way valve 86 is connected to the hot water supply passage 50a. The connection / cutoff between the auxiliary heat source forward passage 50b and the connection / cutoff between the auxiliary heat source forward passage 50b and the hot water return side passage 50d can be switched alternatively. A check valve 50e is installed in the hot water supply passage 50a, and a heat utilization circulation pump 87 and a flow rate sensor 88 are installed in the auxiliary heat source forward passage 50b. A drainage passage 89 provided with a safety valve 89a is connected to the auxiliary heat source forward passage 50b.

  The heat exchanger 42b of the auxiliary heat source unit 42 is connected between the auxiliary heat source forward side passage 50b and the heat exchange forward side passage 50c. The heat of the first and second heat exchangers 43 and 44 is between a pair of branch passages in the downstream portion of the heat exchange forward passage 50c and a pair of branch passages in the upstream portion of the hot water return passage 50d. Exchange passage portions 43a and 44a are connected to each other. A heating heat exchange outlet electromagnetic valve 91 and a bath heat exchange outlet electromagnetic valve 92 are respectively installed in a pair of branch passages of the hot water return side passage 50d. A flow rate sensor 93 is installed in the hot water return side passage 50d.

  A hot water supply passage 58 connected to the hot water supply circuit 47 is branched from the heat exchange outgoing side passage 50c, and a tank water proportional valve 94 is installed in the hot water supply passage 58. With this hot water supply passage 58, hot water whose temperature has decreased in the hot water storage tank 41 or low temperature clean water introduced from the water supply circuit 46 via the second bypass passage 52 is heated by the auxiliary heat source unit 42 to obtain hot hot water. The hot water supply circuit 47 can be supplied.

Hot hot water from the hot water storage tank 41 through the heat utilization circulation pump 87 is sent from the hot water supply passage 50a through the auxiliary heat source forward passage 50b to the heat exchanger 42b of the auxiliary heat source unit 42 and reheated as necessary. The hot water passing through the auxiliary heat source unit 42 is sent to the first and second heat exchangers 43 and 44 through the heat exchange forward passage 50c, and heat exchange is performed in the first and second heat exchangers 43 and 44. The hot water is returned to the lower part of the hot water storage tank 41 through the hot water return side passage 50d, the second bypass passage 52, and the downstream water supply passage 46c.
The hot water storage / heating unit 3 is provided with a plurality of drain plugs, but detailed description thereof is omitted.

Next, the replenishment passage 95 unique to the present application for connecting the hot water circulation circuit 45 and the hot water heating circuit 48 will be described.
As shown in FIG. 1, the supply passage 95 is for supplying heating water to the expansion tank 80, the upstream end is branched and connected to the downstream return side passage 45 d of the hot water circulation circuit 45, and the downstream end is hot water heating. The circuit 48 is configured to be connected to the upper end portion of the expansion tank 80. An opening / closing valve (heating heating water electromagnetic valve) 96 controlled by the control unit 97 is installed in the supply passage 95. That is, hot water flowing through the hot water circulation circuit 45 can be supplied to the expansion tank 80 as necessary.

  According to the configuration in which the supply passage 95 is provided, the open / close valve 96 is opened when it is desired to drain hot hot water flowing through the downstream return side passage 45d of the hot water circulation circuit 45 or when heating water is supplied to the expansion tank 80. In this state, hot hot water can be surely drained or supplied to the expansion tank 80 of the hot water heating circuit 48 via the supply passage 95. Therefore, the conventional supply passage 95 for heating water supply and opening / closing can be performed. By sharing the valve 96 for draining hot water from the hot water circulation circuit 45, it is not necessary to newly install a dedicated drainage passage or drainage on-off valve, and the cost can be reduced.

  Further, in the downstream return side passage 45d of the hot water circulation circuit 45, the check valve 65 is provided on the downstream side of the branching portion 45e where the supply passage 95 branches, so that the hot water on the upper high temperature side in the hot water storage tank 41 is supplied to the supply passage 95. The hot water in the hot water storage tank 41 does not move and maintains a stable state. Therefore, low temperature clean water can be reliably supplied to the upstream forward passage 45a of the hot water circulation circuit 45 through the lower part of the hot water storage tank 41, The temperature of the hot water flowing through the hot water circulation circuit 95 can be greatly reduced.

Next, the control unit 97 will be described.
The hot water storage / heating device 1 is controlled by a control unit 97 (corresponding to control means). Various temperature sensors, various flow sensors, signals of the water level switch 39 and the water level sensors 80a and 80b are transmitted to the control unit 97, and the control unit 97 operates the power generation unit 2 and the hot water storage / heating unit 3 and the various valve members. Controls switching, operation / stop of various pumps, switching of open / close states of various on-off valves, etc., and performs various operations (exhaust heat recovery operation, reheating operation, heating operation, hot water supply operation, etc.).

Next, the operation and effect of the hot water storage / heating device 1 of the present invention will be described.
The hot water storage / heating device 1 includes a normal exhaust heat recovery operation shown in FIG. 1 according to a storage state of pure water in the pure water tank 32 of the power generation unit 2, a hot water storage state of the hot water storage tank 41, and the like. Three pure water recovery operation modes of the exhaust heat discharge operation shown in FIG. 3 and the hot water discharge operation shown in FIG. 4 are provided.

  As shown in FIG. 1, in a normal exhaust heat recovery operation, the control unit 97 sets the hot water switching valve 62 to the hot water storage tank 41 side and controls the on-off valve 96 to be closed. The hot water flowing into the heat exchange passage 9a from the lower end of the hot water storage tank 41 through the upstream forward passage 45a and the downstream forward passage 45b is discharged from the off-gas combustion chamber 24 by driving the exhaust heat recovery circulation pump 64. Heat exchange with the exhaust gas is performed to warm the hot water, and the heated hot water is stored in the hot water storage tank 41 through the upstream return side passage 45c and the downstream return side passage 45d. By repeating this operation, the hot water storage tank 41 has a high temperature. Hot water is stored.

  On the other hand, in the power generation unit 2, the water vapor contained in the exhaust gas is cooled by the heat exchanger 9 to generate condensed water, and this condensed water is sent to the processing tank 31 via the recovery passage 34. The impurities in the condensed water are removed from the inside, and the purified water is sent to the pure water tank 32 and temporarily stored. Thereafter, the water stored in the pure water tank 32 is sent to the evaporator 22 of the power generation module 4 by the pure water pump 33 and reused as reforming water.

  However, the temperature of the hot water flowing from the hot water storage tank 41 to the heat exchanger 9 through the upstream outward passage 45a and the downstream outward passage 45b rises due to the heat storage state of the hot water storage tank 41, and eventually the hot water storage tank 41 is fully stored. The hot water circulating in the hot water circulation circuit 45 reaches a temperature near the dew point in the heat exchanger 9. Then, the temperature drop of the exhaust gas is reduced, the amount of condensed water generated in the heat exchanger 9 is reduced, and a sufficient amount of condensed water cannot be recovered, and the supply of reforming water is insufficient.

  In this case, the plurality of tank hot water temperature sensors 61a to 61d of the hot water storage tank 41 detect the full storage state, or the temperature of the hot water in the upstream outward passage 45a is equal to or higher than a predetermined temperature by the circulating hot water temperature sensor 66a (for example, 80 ° C.). When the water level switch 39 of the pure water tank 32 detects a lowered water level (medium level L2), the operation mode is described below based on these detection signals. Switch to exhaust heat exhaust operation. The full animal state is a state in which the hot water storage tank 41 is filled with hot hot water of, for example, 80 ° C.

  As shown in FIG. 3, in the exhaust heat discharge operation, the control unit 97 sets the hot water storage switching valve 62 to the bypass side, closes the open / close valve 96, activates the radiator 63, and exhaust heat recovery circulation pump. Increase the number of revolutions of 64. As a result, a closed circuit including the downstream forward side passage 45b, the upstream return side passage 45c, and the first bypass passage 51 is formed, and the exhaust heat recovery circulation pump 64 is driven to flow through the downstream forward side passage 45b and the radiator 63. The hot water that is cooled and flows into the heat exchange passage 9a exchanges heat with the exhaust gas discharged from the off-gas combustion chamber 24, warms the hot water, and the heated hot water passes through the upstream return side passage 45c and passes through the first bypass passage. 51, and cooled again by the radiator 63. By repeating this operation, the condensed water is recovered from the water vapor in the exhaust gas while forcibly cooling the hot water.

  However, even if the exhaust heat exhaust operation for recovering pure water while forcibly cooling hot water as described above is executed and a certain time elapses, the outdoor air temperature is high in summer or the like, and the radiator 63 is operated, In some cases, the hot water flowing through the downstream going-side passage 45b cannot be efficiently cooled, and recovery of the water level of the pure water tank 32 is not expected. In this case, the pure water recovery operation mode is switched from the exhaust heat discharge operation to the hot water discharge operation described below.

  As shown in FIG. 4, in the hot water discharge operation, the control unit 97 sets the hot water switching valve 62 to the hot water storage tank 41 side, opens the on-off valve 96, and stops the radiator 63 according to the outside air temperature. Select drive. As described above, the temperature of the hot water in the hot water storage tank 41 (or in the upstream forward passage 45a) is not less than a predetermined set temperature (80 degrees or more), and the water in the pure water tank 32 has a predetermined set water level (intermediate level L2). ), The hot water circulation to the hot water storage tank 41 is switched to the drainage to the expansion tank 80 via the on-off valve 96, and low temperature clean water is introduced into the hot water storage tank 41 from the water supply circuit 46.

  Next, the low temperature clean water flowing into the heat exchange passage 9a through the lower part of the hot water storage tank 41, the upstream forward passage 45a and the downstream forward passage 45b is included in the exhaust gas discharged from the offgas combustion chamber 24. The water is exchanged with the steam to warm the water, and the heated water is discharged to the expansion tank 80 through the upstream return side passage 45c, the downstream return side passage 45d, and the supply passage 95, and the expansion tank 80 is full. In this case, the water is discharged to the outside through the drainage passage 81.

  On the other hand, since the cooling capacity of the heat exchanger 9 is increased by introducing low temperature clean water in the power generation unit 2, more condensed water is generated than in the case of the exhaust heat discharge operation, and this condensation Water is sent to the processing tank 31 through the recovery passage 34, processed in the processing tank 31, and then stored in the pure water tank 32.

  In this way, heat exchange with steam is promoted by using low temperature clean water instead of hot water in the hot water storage tank 41 in a fully stored state, and a sufficient amount of condensed water is obtained. It can be recovered, and it is possible to avoid a power generation operation stop due to a shortage of water for reforming. Thereafter, when the water level of the pure water tank 32 recovers to the set water level or higher (upper level L1), the introduction of clean water from the clean water source may be stopped and switched to normal exhaust heat recovery operation.

  As described above, when the hot water storage tank 41 is fully stored or when the temperature of the hot water in the outgoing side passage (upstream outgoing side passage 45a) of the hot water circulation circuit 45 exceeds a predetermined temperature, When the condensed heat cannot be sufficiently recovered by the exhaust heat recovery operation, the on-off valve 96 is opened, so that the hot water on the upper high temperature side in the hot water storage tank 41 is maintained without being drained, and the hot water circulation circuit 45 is maintained. The hot hot water can be drained into the expansion tank 80 through the supply passage 95. For this reason, since it is possible to newly introduce low temperature clean water into the hot water circulation circuit 45, it is not necessary to provide an expensive and large radiator 63 in the hot water circulation circuit 45, and manufacturing costs and operation costs can be reduced.

  Even when the hot water storage tank 41 is fully charged, it is possible to introduce new low-temperature clean water into the hot water circulation circuit 45 via the lower part of the hot water storage tank 41, so that a sufficient amount of condensed water can be obtained from the exhaust gas. It can be recovered. Further, in the pure water recovery operation mode, when the exhaust heat discharge operation is omitted and the exhaust heat recovery operation is switched directly to the hot water discharge operation, the radiator 63 can be omitted.

  Next, a second embodiment in which the hot water storage / heating device 1 of the first embodiment is partially changed will be described. In the first embodiment, the pure water recovery operation is described. In the second embodiment, the air bleeding operation is described.

  In this embodiment, the air supply of the hot water circulation circuit 45 is described using the replenishment passage 95, and the air release of the hot water storage tank 41, the hot water supply circuit 47, the bath hot water supply circuit 49, the heat utilization circulation circuit 50, and the like is described. Is omitted. In addition, the flow of water supplied from the water supply source during the air bleeding operation is substantially the same as that shown in FIG. 4 of the first embodiment, and will be described based on FIG.

  First, the control unit 97 sets the open / close valve 96 to the open state at the initial stage of operation or at the time of air bleeding operation after draining the tank. In this state, when low temperature clean water is supplied from the clean water source to the water supply circuit 46, the water supply pressure passes through the lower portion of the hot water storage tank 41 and passes through the upstream forward passage 45a and the downstream forward passage 45b of the hot water circulation circuit 45. It flows into the heat exchange passage portion 9a and flows through the upstream return side passage 45c and the downstream return side passage 45d. Since the check valve 65 is provided on the hot water storage tank 41 side of the downstream return side passage 45d, water does not flow into the downstream return side passage 45d from the upper part of the hot water storage tank 41. Therefore, the water flowing through the downstream return side passage 45d Since the water flows through the replenishment passage 95 to the expansion tank 80 without being interfered with other air-releasing water, the hot water circulation circuit 45 can be quickly vented.

  Further, since the water flowing into the expansion tank 80 flows from the expansion tank 80 through the heating forward side common passage 48a and the heating return side passage 48d by driving the heating circulation pump 82, the hot water heating circuit 48 can be vented. . When the expansion tank 80 becomes full, water is drained to the outside through the drainage passage 81. That is, the hot water heating circuit 48 and the hot water circulation circuit 45 can be vented simultaneously.

  In this way, the control unit 97 opens the on-off valve 96 during the air bleeding operation, so that the hot water circulation circuit can be driven by the supply water pressure of the water supply source without driving the exhaust heat recovery circulation pump 64 of the hot water circulation circuit 45. 45 can be vented, and the time for the venting operation can be shortened.

Next, a mode in which the first and second embodiments are partially changed will be described.
[1] In the second embodiment, the fuel cell type power generation unit 2 has been described as an external heat source. However, the present invention is not limited to this, and a heat pump type heating device, a gas engine, or the like may be employed. In addition to these, various known ones can be used.

[2] In addition, those skilled in the art can implement the present invention by adding various modifications without departing from the spirit of the present invention, and the present invention includes such modifications. It is.

DESCRIPTION OF SYMBOLS 1 Hot water storage heating apparatus 2 Electric power generation unit 3 Hot water storage heating unit 41 Hot water storage tank 45 Hot water circulation circuit 48 Hot water heating circuit 80 Expansion tank 95 Supply passage 96 On-off valve 97 Control unit (control means)

Claims (4)

A hot water storage tank, an external heat source for heating the hot water in the hot water storage tank, a hot water circulation circuit for circulating hot water between the external heat source and the hot water storage tank, and at least heat storage through the heat storage of the hot water storage tank In a hot water storage and heating device comprising a hot water heating circuit having an expansion tank capable of storing heating water,
A replenishment passage having a downstream end connected to the expansion tank and supplying the heating water to the expansion tank; an on-off valve provided in the replenishment passage; and control means for switching an open / close state of the on-off valve. ,
A hot water storage heater characterized in that an upstream end of the replenishing passage is branched and connected to a return side passage of the hot water circulation circuit, and hot water flowing through the hot water circulation circuit can be supplied to the expansion tank via the replenishment passage. apparatus.   The hot water storage and heating device according to claim 1, wherein a check valve is provided downstream of a branching portion where the replenishing passage branches in the return side passage of the hot water circulation circuit.   3. The hot water storage device according to claim 1, wherein the control means opens the on-off valve when the temperature of the hot water in the outgoing side passage of the hot water circulation circuit becomes equal to or higher than a predetermined temperature. Heating device. The hot water storage / heating device according to any one of claims 1 to 3, wherein the control means opens the on-off valve during an air bleeding operation.