JP4938385B2 - Hot water storage hot water supply system - Google Patents

Description

  The present invention relates to a hot water storage hot water supply system in which water heated by power generation heat, solar heat or the like is stored in a hot water storage tank, and hot water is supplied using the water stored in the hot water storage tank. In this specification, it is called water without distinguishing warm water and cold water. Even if it says water, it is not necessarily cold water, and it may be warm water.

  2. Description of the Related Art A hot water storage hot water supply system is known in which water heated by power generation heat or solar heat is stored and supplied. If hot water is stored in a hot water storage tank that is hotter than the temperature required at the location where hot water is used (hot water set temperature), adjust the temperature to the hot water set temperature by mixing the water sent from the hot water tank with tap water Can do. If hot water is stored in the hot water storage tank, it is necessary to supply hot water by heating with an auxiliary heat source such as a burner. In this case, water preheated by generated heat or solar heat is used. Is heated by an auxiliary heat source machine, and less energy is required for heating to the hot water supply set temperature than when heating tap water. The hot water storage system has a high overall heat utilization efficiency.

  In the hot water supply system, it is preferable that the time until the water adjusted to the hot water supply set temperature is available at the hot water use location is short. For example, the user waits with the hot-water tap open until the hot-water temperature rises to the temperature set to the hot-water supply temperature after the hot water tap installed in the kitchen or bath is opened. If this time is long, not only will the amount of wasted water be increased, but it will also give the user a lot of discomfort. It is necessary to shorten the time until water adjusted to the hot water supply set temperature starts to be discharged.

Patent Document 1 discloses a technique in which water in a hot water storage tank is preheated to a temperature higher than a hot water supply set temperature in order to shorten the waiting time.
In the technique of Patent Document 1, the daily use amount of hot water supply and the hot water supply set temperature are monitored by a flow sensor and the thermistor installed in the hot water storage tank, and the heat storage amount required to be stored in the hot water storage tank is predicted based on the monitoring. Preheat until the predicted amount of heat storage is obtained. The preheating operation is performed at night on the previous day by predicting the heat storage amount required for the next day. As a result, the water in the hot water storage tank is preheated to a temperature higher than the hot water supply set temperature.
In the technique of Patent Document 1, water that has been kept warm in a hot water storage tank and tap water are mixed and water adjusted to a hot water supply set temperature is supplied to a hot water supply use location. The time until the water adjusted to the hot water supply set temperature starts to be discharged can be shortened.

JP 2002-181385 A

  In the technique of Patent Document 1, water preheated to a temperature higher than the hot water supply set temperature is kept in a hot water storage tank. Even if the hot water storage tank is insulated from the surroundings, it is inevitable to dissipate heat as long as the heat insulation structure is economically realistic. The higher the water temperature is kept, the higher the heat dissipation loss. The technique of Patent Document 1 is a system in which water preheated to a temperature higher than the hot water supply set temperature is kept, and thus heat dissipation loss is high.

  The present invention has been created in view of the above circumstances, and by preheating the water in the hot water tank, the time until the water adjusted to the hot water supply set temperature starts to be discharged can be shortened. At the same time, a technique is provided that can avoid the problem of increased heat dissipation loss because the preheated water is kept warm in the hot water storage tank.

  The hot water storage type hot water supply system of the present invention includes a hot water storage tank, a heating circulation path for returning water in the lower part of the hot water storage tank to the upper part of the hot water storage tank, means for heating water flowing through the heating circulation path, and a lower part of the hot water storage tank. Heating the water flowing through the auxiliary water supply path, the hot water supply path that leads the water in the upper part of the hot water storage tank to the hot water use point, the auxiliary heating circulation path that returns the hot water tank water to the upper part of the hot water storage tank, and the auxiliary heating circulation path An auxiliary heat source unit that detects the temperature of the upper part of the hot water storage tank, a hot water supply temperature setting unit that sets the temperature of the hot water that is led to the hot water use location, and the temperature detected by the detection unit becomes the preheating temperature. A control device having a preheating mode for operating the auxiliary heat source unit to be maintained is provided. Here, the preheating temperature is lower than the hot water supply temperature set by the hot water supply temperature setting means, and the temperature increase range of the water temperature obtained while passing through the auxiliary heat source machine is reduced from the lowest temperature settable by the hot water supply temperature setting means. It is characterized by being higher than the temperature.

The water in the lower part of the hot water storage tank is sent out to the heating circulation path, heated by the power generated by the fuel cell, solar heat, etc., and returned to the upper part of the hot water storage tank. The water returned to the upper part of the hot water storage tank is not mixed with the low temperature water stored in the lower part of the hot water storage tank, and is stored in the upper part of the hot water storage tank in a high temperature state. Temperature stratification is formed inside the hot water storage tank.
Hot water stored in the upper part of the hot water storage tank is sent out to the hot water supply path. Therefore, high-temperature water can be sent out to the hot water supply path until the amount of heat stored in the hot water storage tank becomes small.
When hot water supply operation is required with the temperature of the water stored in the upper part of the hot water tank lowered, the water is circulated using the auxiliary heating circulation path that returns the water in the hot water tank to the upper part of the hot water tank. The water flowing through the auxiliary heating circulation path is heated by the auxiliary heat source unit. The high-temperature water heated by the auxiliary heat source machine is returned to the upper part of the hot water storage tank and sent to the hot water supply path. The temperature of the water stored in the upper part of the hot water storage tank is homogenized by circulation, and the temperature of the water sent to the hot water supply path is stabilized. The upper part of the hot water storage tank functions as a buffer tank and suppresses the temperature fluctuation of the water sent to the hot water supply path. Even when the amount of heat stored in the hot water storage tank is small, the small amount of stored heat can be used effectively for hot water supply.

In this hot water storage type hot water supply system, when the amount of heat stored in the hot water storage tank decreases, the preheating mode is executed so that the water in the upper part of the hot water storage tank is maintained at the preheating temperature. FIG. 1A shows the preheating temperature of the present invention. In the hot water supply temperature setting means, the user can set the hot water supply set temperature Tα from the temperature range from the minimum temperature Tα _min to the maximum temperature Tα _max . In FIG. 1A, ΔTr is the temperature rise width of the water temperature obtained while passing through the auxiliary heat source machine. The preheating temperature Tp of the present invention is higher than Tα _min −ΔTr and lower than the hot water supply set temperature Tα.
The preheating temperature Tp may be calculated by calculation, or may be a temperature set in advance within the above temperature range. For example, the hot water supply set temperature is often set to around 42 ° C., the lowest settable temperature Tα _min is often around 38 ° C., and ΔTr is often around 15 ° C. If the preheating temperature is set to around 35 ° C., the preheating temperature often satisfies a condition that is higher than Tα _min −ΔTr and lower than the hot water supply set temperature Tα.
According to this system, the preheating temperature of the hot water storage tank can be kept lower than that of the prior art. Therefore, the heat loss from the hot water storage tank that has been preheated can be greatly reduced.

In FIG. 2, the figure showing the temperature change of the upper part of the hot water storage tank of this invention is shown. (1) in FIG. 2 represents a temperature change when hot water is supplied without preheating the water in the hot water storage tank, and (2) in FIG. 2 is a case in which hot water is supplied by preheating the water in the hot water storage tank. It represents the temperature change. In the case of (1), the temperature of the water in the upper part of the hot water storage tank is the water supply temperature Ts when there is a hot water request 1. It takes time ΔT1 to heat from this state to the hot water supply set temperature Tα to discharge the hot water. On the other hand, as shown in (2), if the water in the upper part of the hot water storage tank is preheated to the preheating temperature Tp in advance, the water at the hot water supply set temperature Tα can be supplied to the hot water use location in the time ΔT2. it can.
If preheating to a temperature higher than the temperature Tα _min −ΔTr obtained by subtracting the temperature increase range −ΔTr of the water temperature obtained while passing through the auxiliary heat source machine from the minimum temperature Tα _{min that} can be set by the hot water supply temperature setting means, The time of ΔT2 is not too long. Even if the water in the hot water storage tank is preheated to the hot water supply set temperature Tα or higher, the water existing in the pipe connecting the hot water storage tank and the hot water use location is not discharged. The temperature-controlled water does not begin to come out. If it is heated to a temperature that is lower by the temperature rise width ΔTr of the water temperature obtained while passing through the auxiliary heat source unit, the temperature of the water sent out from the hot water storage tank can be increased by starting the heating with the auxiliary heat source unit when the hot water supply is started. It can be raised quickly. Water whose temperature has been adjusted to the hot water supply set temperature Tα at the hot water use location begins to appear at a delay time that is not much different from the case where the water in the hot water storage tank is preheated to the hot water supply set temperature Tα or higher.
By preheating, it is possible to shorten the time until the water adjusted to the hot water supply set temperature starts to be discharged, and at the same time, the heat dissipation loss increases because the preheated water is kept in the hot water tank. Can be avoided.

The water to be preheated may be only the water stored in the upper part of the hot water storage tank, or may preheat only the water existing at an intermediate height or higher of the hot water storage tank. For example, if a single amount of water used on average in a hot water supply use place such as a kitchen or a wash basin is heated, it is possible to respond quickly when using hot water supply. The waiting time of the user can be shortened.
When a fuel cell or the like starts a power generation operation, the water in the hot water storage tank is sent to the heating circulation path and the entire amount of water in the hot water storage tank is heated, so it is necessary to preheat all the water in the hot water storage tank. There is no. This is also effective in reducing heat loss.

  The preheating temperature of the hot water storage type hot water supply system of the present invention is preferably higher than the temperature obtained by subtracting the temperature increase range of the water temperature obtained while passing through the auxiliary heat source device from the hot water supply set temperature, and preferably lower than the hot water supply set temperature.

  FIG. 1B illustrates the preheating temperature of the present invention. If the preheating temperature Tp is higher than the temperature Tα−ΔTr obtained by subtracting the temperature increase range ΔTr of the water temperature obtained while passing through the auxiliary heat source unit from the hot water supply set temperature Tα, the hot water is quickly discharged if it is lower than the hot water supply set temperature Tα. can do. According to said structure, although the lower limit of preheating temperature Tp changes according to hot water supply preset temperature T (alpha), it is still lower than the conventional heat retention temperature, and there is little heat loss.

  As the temperature rise width ΔTr of the water temperature obtained while passing through the auxiliary heat source device of the hot water storage type hot water supply system of the present invention, it is preferable to use the temperature rise width at the minimum amount of water that operates the auxiliary heat source device.

The temperature rise width ΔTr of the water temperature obtained while passing through the auxiliary heat source machine not only changes depending on the heating capacity of the auxiliary heat source machine, but also changes depending on the amount of water passing through the auxiliary heat source machine. If the amount of water passing through the auxiliary heat source device is small, the temperature increase width ΔTr is large.
At the start of hot water supply, it is important that the supply start timing of water adjusted to the hot water supply set temperature is early even if the desired amount of water is not reached. It is acceptable to reduce the amount of water.
If the amount of water is suppressed at the start of hot water supply, the temperature increase range ΔTr of the water temperature obtained while passing through the auxiliary heat source unit becomes large, and thereby the preheating temperature Tp can be lowered. Heat dissipation loss can be suppressed while preventing the hot water supply start timing from being delayed.

  In the hot water storage type hot water supply system of the present invention, it is preferable not to execute the preheating mode when the hot water supply set temperature is higher than a predetermined temperature.

The hot water supply temperature set in the hot water use location varies depending on the application. For example, when the hot water supply temperature is set to about 40 ° C., it is often required that the time until water adjusted to the hot water supply set temperature starts to be discharged, such as dishwashing and showering, is short. . On the other hand, when the hot water supply set temperature is set to a high temperature of 50 ° C. or higher, for example, when hot water is required to prepare a drink, water adjusted to the hot water supply set temperature is discharged. It is often acceptable that the time to start is a little longer. That is, in order to avoid heat dissipation loss, it is often allowed that the preheating is not performed.
If the preheat mode is not executed when the hot water supply set temperature is higher than the predetermined temperature, preheat it when it is required that the time until the water adjusted to the hot water set temperature begins to be discharged is short. The time until the start of hot water supply can be shortened, and heat dissipation loss can be avoided if a long time is allowed until water adjusted to the hot water supply set temperature starts to be discharged.

  The hot water storage type hot water supply system of the present invention preferably has operation switches for switching whether or not to execute the preheating mode.

There is a trade-off between shortening the time until water adjusted to the hot water supply set temperature begins to be discharged and reducing heat dissipation loss. If operation switches are prepared, the user can select whether or not to perform the preheating operation in the hot water storage type hot water supply system.
The switch for switching whether or not to execute the preheating mode may be operable independently. Or the structure linked with the power switch of a hot water storage type hot-water supply system may be sufficient.

A hot water storage hot water supply system according to a reference aspect of the present invention includes a hot water storage tank, a heating circulation path for returning water below the hot water storage tank to the upper part of the hot water storage tank, means for heating water flowing through the heating circulation path, and hot water storage A water supply path for supplying water to the lower part of the tank, a hot water supply path for leading the water in the upper part of the hot water storage tank to the hot water use location, an auxiliary heating circulation path for returning the hot water tank water to the upper part of the hot water storage tank, and an auxiliary heating circulation path An auxiliary heat source that heats the flowing water and has a variable amount of heating, a hot water temperature setting means that sets the temperature of the hot water that leads to the hot water use location, and a temperature that detects the temperature of the water that is sent from the hot water storage tank to the hot water supply path 1 detection means, second detection means for detecting the temperature of water sent from the hot water storage tank to the auxiliary heat source machine, and the heating amount of the auxiliary heat source machine, the hot water supply temperature set by the hot water supply temperature setting means and the second detection means The heating amount determining means for determining based on the difference in temperature detected in step 1 and the heating of the auxiliary heat source machine while the temperature detected by the first detecting means is lower than the hot water supply temperature set by the hot water supply temperature setting means. Heating amount increasing means for increasing the amount from the heating amount determined by the heating amount determining means.

  The heating amount determination means determines the heating amount of the auxiliary heat source unit based on the difference between the hot water supply set temperature and the temperature detected by the second detection means. The auxiliary heat source machine has a configuration in which the heating amount is variable, and the heating amount is controlled so as to coincide with the heating amount determined by the heating amount determining means. If the heating amount of the auxiliary heat source device is adjusted to the heating amount determined by the heating amount determination means, the water that has passed through the auxiliary heat source device is adjusted to the hot water supply set temperature. In practice, the heating amount determined by the heating amount determination means is often calculated so that the water that has passed through the auxiliary heat source unit has a temperature slightly higher (1-2 ° C.) than the hot water supply set temperature. This is different from the heating amount increasing means here, and the heating amount increasing means remarkably increases the heating amount.

In the hot water storage type hot water supply system of the present invention, the water that has passed through the auxiliary heat source is not sent out as it is to the hot water supply path, but is once returned to the upper part of the hot water storage tank, and then sent from the upper part of the hot water storage tank to the hot water supply path. Between returning from the upper part of the hot water storage tank and being sent out to the hot water supply path, it is mixed with the water existing in the upper part of the hot water storage tank, and the mixed water is sent out to the hot water supply path.
In FIG. 3, the temperature change of the water sent out to a hot water supply path | route is shown.
Graph (2) shows a case where the heating amount of the auxiliary heat source unit matches the heating amount determined based on the difference between the hot water supply set temperature and the temperature detected by the second detection means. Since the temperature of the water that passes through the auxiliary heat source device and is returned to the upper part of the hot water storage tank is the hot water supply set temperature, it takes time Δt2 for the temperature of the water sent to the hot water supply path to rise to the hot water supply set temperature Tα.
Graph (1) shows a case where the heating amount of the auxiliary heat source unit is increased by the heating amount increasing means. Since the temperature of the water passing through the auxiliary heat source unit and returning to the upper part of the hot water storage tank is heated to the hot water supply set temperature or higher, it takes time for the temperature of the water sent to the hot water supply path to rise to the hot water supply set temperature Tα. Δt1 can be short.
If the temperature of the water sent out to the hot water supply path becomes equal to the hot water supply setting means, the heating amount of the auxiliary heat source unit becomes the heating amount determined based on the difference between the hot water supply set temperature and the temperature detected by the second detection means. The temperature of the water that is adjusted and passes through the auxiliary heat source unit and returned to the upper part of the hot water storage tank is lowered to the hot water supply set temperature. The driving | running which sends out the water of hot-water supply preset temperature to a hot-water supply path | route can be continued.
As described above, the reference hot water storage tank of the present invention functions as a buffer tank. For this reason, even if the heating amount of the auxiliary heat source machine is changed, the temperature change is buffered by the hot water storage tank, and the hot water supply temperature is hardly affected. The heating amount of the auxiliary heat source machine can be varied without considering the influence on the hot water supply temperature.

  The heating amount determination unit and the heating amount increase unit may have a hardware configuration that can be connected to the auxiliary heat source unit, or may be configured by a program that controls the auxiliary heat source unit.

In the reference hot water storage hot water supply system of the present invention, while the temperature detected by the first detection means is lower than the hot water supply set temperature, the heating amount of the auxiliary heat source machine may be the maximum heating amount.

  According to this, it is possible to further shorten the time until the hot water supply starts at the hot water supply temperature.

  The “upper part of the hot water storage tank” in the present specification can be changed according to various demands when the hot water storage type hot water supply system is actually used. For example, when it is desired to suppress the temperature fluctuation of water sent to the hot water supply path as much as possible, the upper range of the hot water storage tank is widened. Specifically, the position where the upper end of the auxiliary heating circulation path is connected to the hot water storage tank is changed downward. As a result, the capacity of the water stored in the upper part of the hot water storage tank serving as a buffer increases, and the temperature fluctuation of the water sent to the hot water supply path can be effectively suppressed. In addition, in order to shorten the time until the start of hot water supply at the hot water supply set temperature as much as possible, the upper range of the hot water storage tank is made narrow. Specifically, the position where the upper end of the auxiliary heating circulation path is connected to the hot water storage tank is changed upward, and the position where the lower end of the auxiliary heating circulation path is connected to the hot water storage tank is also changed upward. As a result, it is possible to further shorten the time until the hot water supply temperature is started.

  With the above configuration, the rising timing of the temperature of the water sent out to the hot water supply path at the start of hot water supply can be accelerated, and the time from when there is a hot water request until the start of hot water supply at the hot water supply set temperature can be shortened. The waiting time of the user is shortened, and the user's discomfort waiting for the start of hot water can be reduced.

The preferred embodiments of the present invention will be described below.
(Embodiment 1) A means for calculating and storing the preheating temperature is provided.
(Mode 2) The preheating temperature is set in advance.
(Mode 3) An on-off valve is interposed in a path for returning the water that has passed through the auxiliary heat source unit to the upper part of the hot water storage tank.
(Mode 4) A branch path is provided for returning the water that has passed through the auxiliary heat source unit to the intermediate height of the hot water storage tank.
(Mode 5) An on-off valve is interposed in a branch path that returns the water that has passed through the auxiliary heat source unit to the intermediate height of the hot water storage tank.
(Mode 6) A bypass path is provided for returning water that has passed through the auxiliary heat source unit to the auxiliary heat source unit by bypassing the hot water storage tank.
(Mode 7) An on-off valve is interposed in a bypass path for returning water that has passed through the auxiliary heat source unit to the auxiliary heat source unit.
(Embodiment 8) The auxiliary heating circulation path includes a state in which water that has passed through the auxiliary heat source unit is returned to the upper part of the hot water storage tank, a state in which the water is returned to the intermediate height of the hot water storage tank, and an auxiliary heat source that bypasses the hot water storage tank. You can switch between the states returned to the machine.
(Embodiment 9) Water flowing through the heating circulation path can be heated with the exhaust gas that heats the reformer.
(Embodiment 10) By cooling the generator, it heats the water flowing through the heating circulation path with the heated cooling water and cools the cooling water.

Embodiments of the present invention will be described with reference to the drawings. Regarding the common parts of the respective embodiments, a duplicate description is omitted.
(First embodiment)
In FIG. 4, the figure showing the schematic structure of the hot water storage type hot-water supply system 1 of a present Example is shown. A heating circulation path 20 is connected to the hot water storage tank 10. A circulation pump 22 is arranged in the heating circulation path 20, and when the circulation pump 22 is operated, water stored in the lower part of the hot water storage tank 10 passes through the heating circulation path 20 and reaches the upper part of the hot water storage tank 10. Returned.
The heating circulation path 20 passes through the heat exchanger 24 through which the exhaust gas that has heated the reformer 74 passes and the heat exchanger 26 through which water heated by the generated heat passes, and the power generation unit 70 generates power. During operation, water stored in the lower part of the hot water storage tank 10 is heated by exhaust gas and generated heat and returned to the upper part of the hot water storage tank 10. In the hot water storage tank 10, water heated by heat generated with power generation is stored in a temperature stratified state.
The heating circulation path 20 includes a thermistor 202 that detects the temperature of water sent from the lower part of the hot water storage tank 10, a thermistor 204 that detects the temperature of water heated by heat generated during power generation, and a three-way valve. 28 is arranged. One end of a power generation unit bypass path 29 is connected to the three-way valve 28, and the other end of the power generation unit bypass path 29 is connected to the heating circulation path 20 upstream of the heat exchanger 24. By switching the three-way valve 28, the water sent from the lower part of the hot water storage tank 10 passes through the heat exchanger 24 and the heat exchanger 26 and then returns to the upper part of the hot water storage tank 10, and the heat exchanger 24 and the heat The state is switched between the state of bypassing the exchanger 26 and returning to the upper part of the hot water storage tank 10.

The power generation unit 70 shown in FIG. 4 includes a reformer 74, a burner 72 that heats the reformer 74, and a fuel cell 76.
The reformer 74 reforms a fuel gas such as methanol to produce hydrogen gas. The produced hydrogen gas is supplied to the fuel cell 76 via the hydrogen gas supply path 704. In order to reform the fuel gas to produce hydrogen gas by the reformer 74, it is necessary to maintain the reformer 74 at a high temperature. The reformer 74 is maintained at a high temperature by the combustion heat of the burner 72. The exhaust gas from the burner 72 is still hot after the reformer 74 is heated, and heats the water flowing through the heating circulation path 20 when passing through the heat exchanger 24. The heat of the exhaust gas is recovered and stored in the hot water storage tank 10.
The fuel cell 76 generates electricity by reacting the hydrogen gas supplied from the reformer 74 with oxygen in the air. When the fuel cell 76 generates power, generated heat is generated. A cooling water passage 706 passes through the fuel cell 76 in order to cool the fuel cell 76. Water flowing through the cooling water passage 706 cools the fuel cell 76 and maintains the fuel cell 76 at a temperature suitable for power generation. The water heated by cooling the fuel cell 76 passes through the heat exchanger 26 and heats the water flowing through the heating circulation path 20. The water cooled by heating the water flowing through the heating circulation path 20 passes through the fuel cell 76 again. The generated heat is recovered and stored in the hot water storage tank 10.
The controller 80 described later burns the burner 72 during the power generation operation, supplies fuel gas to the reformer 74, and operates the circulation pump 22.

A water supply path 30 for supplying tap water to the hot water storage tank 10 is connected to the bottom of the hot water storage tank 10 in FIG. A pressure reducing valve 32 for reducing the pressure of tap water, a water supply thermistor 302 for measuring the water supply temperature, a flow rate sensor 34 for measuring the water supply amount, a water supply servo 36 and a mixing servo 38 are interposed in the water supply path 30. The mixing servo 38 is disposed at a branch point between the water supply path 30 and the mixing path 46.
When the water pressure in the hot water storage tank 10 decreases, tap water decompressed by the pressure reducing valve 32 is supplied to the hot water storage tank 10 from the water supply path 30. The feed water temperature detected by the feed water thermistor 302 and the feed water amount detected by the flow sensor 34 are input to the controller 80.
A drainage path 90 is connected to the downstream side of the mixing servo 38 of the water supply path 30. A drain valve 92 is interposed in the drain path 90. The drain valve 92 is manually opened and closed. When the drain valve 92 is opened, the water in the hot water storage tank 10 is drained to the outside through the drain path 90.

A hot water supply path 40 for supplying hot water stored in the upper part of the hot water storage tank 10 to the hot water tap 48 is connected to the ceiling (upper part) of the hot water storage tank 10 in FIG. The hot-water taps 48 are disposed at each location where hot water is used such as a bathroom, a washroom, and a kitchen. A hot water solenoid valve 42, a high temperature thermistor 402, a hot water supply thermistor 404, and a hot water supply amount sensor 44 are interposed in the hot water supply path 40. The above-described mixing path 46 is connected to the hot water supply path 40. The mixing path 46 is downstream of the hot water solenoid valve 42 and is connected between the high temperature thermistor 402 and the hot water supply thermistor 404.
The high temperature thermistor 402 detects the temperature of water sent out from the hot water storage tank 10 and before being mixed with tap water from the water supply path 30. The hot water supply thermistor 404 detects the temperature of the water after mixing. The mixing ratio between the amount of hot water from the hot water supply path 40 and the amount of cold water from the mixing path 46 is adjusted by the opening degree of the mixing servo 38. By adjusting the opening degree of the mixing servo 38, the temperature can be adjusted to a preset hot water supply temperature.
The temperature detected by the high temperature thermistor 402 and the temperature detected by the hot water supply thermistor 404 are input to the controller 80. The amount of hot water measured by the hot water amount sensor 44 is input to the controller 80. The controller 80 adjusts the opening degree of the mixing servo 38 based on the detected temperature of the water supply thermistor 302, the detected temperature of the high temperature thermistor 402, and the preset hot water supply temperature. With this configuration, even if the temperature of the water stored in the upper part of the hot water storage tank 10 is higher than the hot water supply set temperature, the water adjusted to the hot water supply set temperature can be supplied.
A first tank thermistor 101 is installed at the upper part of the hot water storage tank 10, a second tank thermistor 102 is installed at the intermediate height of the hot water storage tank 10, and a third tank thermistor 103 is installed at the lower part of the hot water storage tank 10. Is installed. The temperatures measured by these thermistors 101, 102, 103 are input to the controller 80.

An auxiliary heating circulation path 50 is provided between an intermediate height of the hot water storage tank 10 in FIG. 4 (a height substantially equal to the second tank thermistor 102) and the upper portion of the hot water storage tank 10. A circulation pump 52 is disposed in the auxiliary heating circulation path 50, and the water sent from the intermediate height of the hot water storage tank 10 is returned to the upper part of the hot water storage tank 10. An on-off valve 55 is interposed on the upstream side of the hot water storage tank 10.
An auxiliary heat source inlet thermistor 502, a circulation pump 52, an auxiliary heating circulation amount sensor 504, and an auxiliary heating circulation amount servo 54 are interposed in the auxiliary heating circulation path 50. The auxiliary heat source inlet thermistor 502 detects the temperature of the water sent from the intermediate height of the hot water storage tank 10. The circulation pump 52 circulates the water in the auxiliary heating circulation path 50. The auxiliary heating circulation amount sensor 504 detects the flow rate of water flowing through the auxiliary heating circulation path 50. The temperature detected by the auxiliary heat source inlet thermistor 502 and the flow rate detected by the auxiliary heating circulation amount sensor 504 are input to the controller 80. The controller 80 controls the opening degree of the auxiliary heating circulation amount servo 54 based on the input temperature, flow rate, etc., and adjusts the flow rate of water flowing through the auxiliary heating circulation path 50. Opening / closing of the on-off valve 55 is controlled by the controller 80.

The auxiliary heating circulation path 50 in FIG. 4 passes through the auxiliary heat source unit 60. Inside the auxiliary heat source machine 60, a latent heat exchanger 62, a sensible heat exchanger 64, a burner 68, and an auxiliary heat source outlet thermistor 66 are arranged.
The burner 68 heats the water flowing through the auxiliary heating circulation path 50 with the sensible heat exchanger 64. The exhaust gas that has passed through the sensible heat exchanger 64 still contains high-temperature water vapor, and condensation occurs when passing through the latent heat exchanger 62 through which the water before being heated by the sensible heat exchanger 64 flows. The water passing through the latent heat exchanger 62 is heated. The auxiliary heat source unit 60 efficiently heats the water flowing through the auxiliary heating circulation path 50 using the latent heat exchanger 62 and the sensible heat exchanger 64. The latent heat exchanger 62 is provided with a drain 62 for collecting and discharging the condensed drain, and a neutralizer (not shown) is interposed in the drain path (not shown). The auxiliary heat source outlet thermistor 66 detects the temperature of the water after being heated by the auxiliary heat source device 60. The detected temperature is input to the controller 80.

  An auxiliary heating circulation branch 56 branches from the auxiliary heating circulation path 50. The auxiliary heating circulation branch 56 branches from the auxiliary heating circulation path 50 on the downstream side of the auxiliary heat source device 60 and is connected to an intermediate height of the hot water storage tank 10. An opening / closing valve 58 is interposed in the auxiliary heating circulation branch 56. Opening / closing of the on-off valve 58 is controlled by the controller 80.

  When the circulation pump 52 is driven and water starts to circulate through the auxiliary heating circulation path 50, the on-off valve is controlled by the temperature detected by the auxiliary heat source outlet thermistor 66 and the tank thermistors 101, 102, 103 in the hot water storage tank 10. One of the valves 55 and 58 is selected and opened by the controller 80.

When the on-off valve 55 is opened, a circulation path for returning the water circulating through the auxiliary heating circulation path 50 to the upper part of the hot water storage tank 10 is formed, which can be used to return hot water to the hot water storage tank 10 for hot water storage. it can. Since the hot water is returned to the upper part of the hot water storage tank 10, the water can be sent out to the hot water supply path 40.
When the on-off valve 58 is opened, a circulation path for returning the water circulating through the auxiliary heating circulation path 50 to the intermediate height of the hot water storage tank 10 is formed. For example, when the temperature of the water that has passed through the auxiliary heat source device 60 is low, returning to the upper part of the hot water storage tank 10 disturbs the temperature stratification state that exists at the upper part of the hot water storage tank 10, so that hot water can be sent to the hot water supply path 40. become unable. When the on-off valve 58 is opened, the low temperature water can be returned to the intermediate height of the hot water storage tank 10, and the water stored in the upper part of the hot water storage tank 10 can be used for hot water supply.

The controller 80 in FIG. 4 includes a CPU 82, a storage unit 84, and a preheating mode execution unit 86. The controller 80 stores various control programs (not shown). The storage means 84 stores the preheating temperature calculated by the preheating mode execution means 86 and the CPU 82. The preheating mode execution means 86 is embodied by a control program for causing the auxiliary heat source unit 60 to perform a preheating operation and the CPU 82.
The controller 80 inputs operation signals from the input means 110, inputs signals from the various sensors described above, and controls the various pumps, valves, burners and the like described above according to the stored control program.
The input means 110 includes a power switch 112 that outputs a system on signal and an off signal, and a hot water supply temperature setting means 114 that outputs a hot water supply set temperature set by an operator. The input means 110 is operated by the user. A signal output from the input unit 110 is input to the controller 80. When the power switch 112 is operated and an ON signal is output, the hot water storage type hot water supply system 1 determines whether or not the preheating mode is executed.

Hereinafter, various operations of the hot water storage type hot water supply system 1 will be described.
(Heat storage operation by power generation unit)
While the power generation unit 70 of FIG. 4 is performing the power generation operation, the circulation pump 22 of the heating circulation path 20 is driven, and the cooling water heated by the generated heat is transferred to the heat exchanger via the cooling water passage 706. 26, the exhaust gas that has heated the reformer 74 passes through the heat exchanger 24 via the discharge path 702.
The water sent out from the lower part of the hot water storage tank 10 is heated by passing through the heat exchanger 24 and the heat exchanger 26, and the heated water is returned to the upper part of the hot water storage tank 10. As a result, the exhaust gas heat generated with the heating of the reformer 74 and the generated heat generated with the power generation of the fuel cell 76 are stored in the hot water storage tank 10. The water in the hot water storage tank 10 is heated from above.

(Auxiliary heating circulation path switching operation)
FIG. 5 shows a flowchart of the switching operation of the auxiliary heating circulation path 50. In step S2, it is determined whether or not the circulation pump 52 interposed in the auxiliary heating circulation path 50 has been driven. In the present embodiment, the circulation pump 52 is driven when the preheating operation is performed and when the combustion hot water supply operation is performed. When the circulation pump 52 is driven (when the determination is YES), the process proceeds to step S4. When the circulation pump 52 is not driven (when the determination is NO), it waits until the drive of the circulation pump 52 is started. Although not shown, when the circulation pump 52 is driven, the auxiliary heat source unit 60 is operated to heat the water flowing through the auxiliary heating circulation path 50.
In step S4, the auxiliary heat source outlet thermistor 66 detects the temperature Tβ of the water that has passed through the auxiliary heat source unit 60. The detected temperature Tβ is input to the controller 80.
In step S6, the first tank thermistor 101 detects the temperature T1 of the water in the upper part of the hot water storage tank 10. The detected temperature T1 is input to the controller 80.
In step S8, it is determined whether or not the temperature Tβ detected by the auxiliary heat source outlet thermistor 66 is equal to or higher than the temperature T1 detected by the first tank thermistor 101. When Tβ is equal to or greater than T1 (when the determination is YES), the water heated by the auxiliary heat source device 60 is hotter than the water stored in the upper part of the hot water storage tank 10, and the process proceeds to step S10. When Tβ is lower than T1 (when the determination is NO), the water stored in the upper part of the hot water storage tank 10 is hotter than the water heated by the auxiliary heat source unit 60, and the process proceeds to step S12.
In step S10, the water heated by the auxiliary heat source unit 60 is hotter than the water stored in the upper part of the hot water storage tank 10 in the determination in step S8, so the on-off valve 55 is opened (not shown but opened / closed). The valve 58 is closed). When the on-off valve 55 is opened, a circulation path for returning the water circulating through the auxiliary heating circulation path 50 to the upper part of the hot water storage tank 10 is formed. The amount of heat stored in the hot water storage tank 10 can be increased without disturbing the temperature stratification state of the hot water storage tank 10.
In step S12, since the water stored in the upper part of the hot water storage tank 10 is higher than the water heated by the auxiliary heat source unit 60 in the determination in step S8, the on-off valve 58 is opened (not shown but opened / closed). The valve 55 is closed). When the on-off valve 58 is opened, a circulation path for returning the water circulating through the auxiliary heating circulation path 50 to the intermediate height of the hot water storage tank 10 is formed. The amount of heat stored in the hot water storage tank 10 can be increased without disturbing the temperature stratification state of the hot water storage tank 10.
In step S14, it is determined whether the circulation pump 52 has been stopped. When the preheating operation is completed and when the combustion hot water supply operation is completed, the driving of the circulation pump 52 is stopped. When the circulation pump 52 is stopped, the auxiliary heat source unit 60 is also stopped. When the circulation pump 52 is stopped (when the determination is YES), the process proceeds to step S16. When the circulation pump 52 is not stopped (when the determination is NO), the processing from step S4 to step S14 is repeated.
In step S16, the open / close valve opened by the determination process in step S8 is closed, and the switching operation of the auxiliary heating circulation path 50 is completed.
The processing from step S2 to step S16 is executed by the CPU 82 and a control program that causes the CPU 82 to execute the processing from step S2 to step S16.

(Preheating operation with auxiliary heat source machine)
FIG. 6 shows a flowchart of the preheating operation by the auxiliary heat source machine. In step S <b> 20, it is determined whether or not an ON signal is input to the controller 80 from the power switch 112 provided in the input unit 110. When the ON signal is input (when the determination is YES), the process proceeds to step S22. When the on signal is not input (when the determination is NO), the process waits until the on signal is input.
In step S <b> 22, the hot water supply set temperature Tα set by the input unit 110 is input to the controller 80. The hot water supply set temperature Tα is set by the user operating the hot water supply temperature setting means 114 provided in the input means 110.
In step S24, it is determined whether the hot water supply set temperature Tα is lower than 45 ° C. When hot water supply set temperature Tα is lower than 45 ° C. (when the determination is YES), the routine proceeds to step S26 in order to perform the preheating operation. When the hot water supply set temperature Tα is 45 ° C. or higher (when the determination is NO), the preheating operation is not executed, so the operation process of the preheating operation is skipped.
In step S26, the preheating temperature Tp is calculated. Preheating temperature Tp is lower than the hot water set temperature T [alpha, hot water temperature setting unit 114 temperature by subtracting the temperature Yutakahaba ΔTr of the resulting water temperature during passage through the auxiliary heat source unit 60 from the lowest temperature T [alpha _min settable in T [alpha _min - It is calculated from a temperature range higher than ΔTr. In this embodiment, when the minimum temperature Tα _min that can be set by the hot water supply temperature setting means 114 is 30 ° C., the hot water supply set temperature Tα is 40 ° C., and the temperature increase width ΔTr is 10 ° C., the preheating temperature Tp is 20 ° C. It is set in a temperature range higher and lower than 40 ° C. The preheating temperature Tp can be calculated by the following equation.

For example, the preheating temperature Tp = 25 ° C. is obtained from the above formula.
In step S28, the preheating temperature Tp calculated in step S26 is stored in the storage means 84. The preheating temperature Tp stored in this step is rewritten every time the operation process in the preheating mode is executed.
In step S30, the first tank thermistor 101 detects the temperature T1 of the water in the upper part of the hot water storage tank 10. The detected temperature T1 is input to the controller 80.
In step S32, it is determined whether or not the preheating temperature Tp is higher than the temperature T1 detected by the first tank thermistor 101. When Tp is higher than T1 (when the determination is YES), it is considered that the amount of heat stored in the hot water storage tank 10 is insufficient, and the process proceeds to step S34 to execute the preheating operation. When Tp is equal to or lower than T1 (when the determination is NO), it is considered that there is a sufficient amount of heat stored in the hot water storage tank 10 and the preheating operation is not executed, so the operation process of the preheating operation is skipped.

In step S34 of FIG. 6, the circulation pump 52 is driven. When the circulation pump 52 is driven, either the on-off valve 55 or 58 is opened by the selection process of the primary heating primary circulation path in FIG. The water in the hot water storage tank 10 is sent out to the auxiliary heating circulation path 50, and the water that has passed through the auxiliary heat source unit 60 is returned to the hot water storage tank 10 from the circulation path formed by the operation of selecting the circulation path shown in FIG. It is.
In step S36, the auxiliary heat source unit 60 is operated. When the auxiliary heat source unit 60 is operated, the burner 68 is ignited to heat the water passing through the auxiliary heat source unit 60. The temperature detected by the auxiliary heat source outlet thermistor 66 is input to the controller 80, and the controller 80 controls the combustion amount of the burner 68 based on this temperature.
In step S <b> 38, the second tank thermistor 102 detects the temperature T <b> 2 of the intermediate height water in the hot water storage tank 10. The detected temperature T2 is input to the controller 80.
In step S40, it is determined whether or not the temperature T2 detected by the second tank thermistor 102 is equal to or higher than the preheating temperature Tp. When T2 is higher than Tp (when the determination is YES), it is considered that water at an intermediate height from the upper part of hot water storage tank 10 has obtained a heat storage amount of at least Tp ° C., and the process proceeds to step S42. When T2 is lower than Tp (when the determination is NO), it is considered that there is not yet a sufficient heat storage amount in the water at the intermediate height from the upper part of hot water storage tank 10, and the process of step S38 is repeated.
In step S42, the circulation pump 52 is stopped. When the circulation pump 52 is stopped, either the on-off valve 55 or 58 opened by the selection process of the primary heating primary circulation path in FIG. 3 is closed.
In step S44, the auxiliary heat source unit 60 is stopped. When the auxiliary heat source unit 60 is stopped, the burner 68 is also extinguished and the preheating operation is terminated.
The processing from step S20 to step S44 is executed by the preheating mode execution means 86.

The preheating temperature Tp calculated in step S26 is lower than the hot water supply set temperature Tα, and the temperature increase range of the water temperature obtained while passing through the auxiliary heat source unit 60 is reduced from the minimum temperature Tα _{min that} can be set by the hot water supply temperature setting means 114. The temperature may be a preset temperature within a temperature range that satisfies the condition that the temperature is higher than the predetermined temperature.

(Hot water operation)
FIG. 7 shows a flowchart of the hot water supply operation. In step S50, it is determined whether or not the detected flow rate of the hot water supply amount sensor 44 is 2.7 liters / min or more. When the detected flow rate of the hot water supply amount sensor 44 is 2.7 liters / min or more (when the determination is YES), it is considered that the hot water tap 48 has been opened and a hot water supply request has been made, and the process proceeds to step S52. When the detected flow rate of the hot water supply amount sensor 44 is less than 2.7 liters / min (when the determination is NO), it is considered that there is no hot water supply request, and waits until there is a hot water discharge request.
In step S52, the hot water solenoid valve 42 is opened. When the hot water supply electromagnetic valve 42 is opened, the water stored in the upper part of the hot water storage tank 10 is sent out to the hot water supply path 40.
In step S <b> 54, the hot water supply set temperature Tα set by the input unit 110 is input to the controller 80. The hot water supply set temperature Tα is set by the user operating the hot water supply temperature setting means 114 provided in the input means 110.
In step S56, the first tank thermistor 101 detects the temperature T1 of the water in the upper part of the hot water storage tank 10. The detected temperature T1 is input to the controller 80.
In step S58, it is determined whether or not the detected temperature T1 of the first tank thermistor 101 is equal to or higher than the hot water supply set temperature Tα. When T1 is equal to or greater than Tα (when the determination is YES), it is considered that the water in the upper part of the hot water storage tank 10 can be used for hot water supply without heating, and the process proceeds to step S60. When T1 is lower than Tα (when the determination is NO), it is considered that hot water cannot be supplied at the hot water supply set temperature Tα unless the water in the hot water storage tank 10 is heated, and the process proceeds to step S62.
In step S60, a non-combustion hot water supply operation is performed. In the non-combustion hot water supply operation, the auxiliary heat source device 60 is not operated, and the circulation pump 52 is not driven. The controller 80 adjusts the opening of the mixing servo 38 so that the temperature detected by the hot water supply thermistor 404 becomes the hot water supply set temperature Tα.

In step S62 of FIG. 7, a combustion hot water supply operation is performed. In the combustion hot water supply operation, the auxiliary heat source unit 60 is operated, and the circulation pump 52 is driven. The water at the intermediate height of the hot water storage tank 10 is sent out to the auxiliary heating circulation path 50 and heated through the auxiliary heat source device 60. During the combustion hot water supply operation, one of the on-off valves 55 and 58 is opened by the process of selecting the auxiliary heating primary circulation path in FIG. 3, and the water heated by the auxiliary heat source unit 60 is returned to the hot water storage tank 10. It is. The water returned to the hot water storage tank 10 is sent out to the hot water supply path 40.
In step S64, the combustion amount of the burner 68 is controlled so that the detected temperature of the auxiliary heat source outlet thermistor 66 becomes Tα + 5 ° C. The amount of combustion of the burner 68 is controlled by the controller 80. The hot water that has passed through the auxiliary heat source device 60 is heated to Tα + 5 ° C. and returned to the hot water storage tank 10 through the auxiliary heating circulation path 50. Water slightly hotter than Tα ° C. is sent from the upper part of the hot water storage tank 10 to the hot water supply path 40, and the hot water is adjusted to the hot water supply set temperature Tα by the mixing servo 38. From the detected temperature of the hot water supply thermistor 302 and the detected temperature of the hot water supply thermistor 404, the opening degree of the mixing servo 38 is adjusted so that the detected temperature of the hot water supply thermistor 404 becomes the hot water supply set temperature Tα.
In step S66, it is determined whether or not the detected flow rate of the hot water supply amount sensor 44 is 2.0 liters / min or less. If the detected flow rate of hot water supply amount sensor 44 is 2.0 liters / min or less (when the determination is YES), it is considered that the use of hot water supply has ended, and the process proceeds to step S68. When the detected flow rate of the hot water supply amount sensor 44 exceeds 2.0 liters / min (when the determination is NO), it is assumed that the hot water tap 48 is still open and hot water is being supplied, and the process is step S54. Return to. After step S54, it is determined that the non-combustion hot water supply operation is performed if the water temperature in the upper part of the hot water storage tank 10 is equal to or higher than Tα ° C, and the combustion hot water supply operation is performed if the water temperature in the upper part of the hot water storage tank 10 is lower than Tα ° C. , Hot water operation is continued.
In step S68, it is considered that the hot water tap 48 has been closed, the hot water solenoid valve 42 is closed, and the hot water supply operation is terminated.
The processing from step S50 to step S68 is executed by the CPU 82 and a control program that causes the CPU 82 to execute the processing from step S50 to step S68.

In the above processing, in step S56, the first tank thermistor 101 detects the temperature T1, and in step S58, a judgment process is performed by comparing the temperature T1 with the hot water supply set temperature Tα. Instead of the temperature, a determination process based on a comparison between the temperature detected by the high temperature thermistor 402 interposed in the hot water supply path 40 and the hot water supply set temperature Tα may be executed.
In step S64, the heating capacity is adjusted so that the detected temperature of the auxiliary heat source outlet thermistor 66 is Tα + 5 ° C., but the temperature detected by the auxiliary heat source outlet thermistor 66 is not limited to Tα + 5 ° C. For example, the combustion hot water supply operation can be performed by setting the detected temperature of the auxiliary heat source outlet thermistor 66 to a temperature closer to the hot water supply set temperature such as Tα + 1 ° C. Alternatively, the temperature detected by the auxiliary heat source outlet thermistor 66 can be set to a temperature that takes into account the degree of water temperature decrease that occurs before reaching the high temperature thermistor 402, for example. By making such a setting, it is not necessary to mix the water from the hot water storage tank 10 and the water from the water supply path 30 during the combustion hot water supply operation. Compared with the case where the water from the hot water storage tank 10 is heated excessively and mixed with cold water, the thermal efficiency is high.

(Second embodiment)
In FIG. 8, the figure showing schematic structure of the hot water storage type hot-water supply system of 2nd Example is shown. In the following description, detailed description of the same components as those of the hot water storage type hot water supply system 1 of the first embodiment is omitted.

  8 includes a power switch 112 that outputs an on signal and an off signal of the system, a hot water temperature setting means 114 that outputs a set hot water set temperature, and a preheating mode execution selection switch. 115. While the preheating mode execution selection switch 115 is operated and the on signal is output, the hot water storage hot water supply system 2 determines whether or not the preheating mode is performed every time the on signal is output by operating the power switch 112. .

(Preheating operation with auxiliary heat source machine)
FIG. 9 shows a flowchart of the preheating operation of the hot water storage type hot water supply system 2. In step S70, it is determined whether or not the preheating mode execution selection switch 115 is turned on. If it is turned on (if the determination is YES), the process proceeds to step S72 in order to determine whether to execute the preheating mode. When it is not turned on (when the determination is NO), the preheating mode execution selection switch 115 is operated and the preheating mode execution determination process is not performed until an on signal is output.
Steps S72 to S76 are the same processes as steps S20 to S24 shown in FIG.

  In step S78, the preheating temperature Tp is calculated. The preheating temperature Tp is calculated from a temperature region that is lower than the hot water supply set temperature Tα and higher than the temperature obtained by subtracting the temperature increase width of the water temperature obtained while passing through the auxiliary heat source device 60 from the hot water supply set temperature Tα. For example, when the hot water supply set temperature Tα is 35 ° C. and the temperature increase width ΔTr is 10 ° C., the preheating temperature Tp is set in a temperature range higher than 25 ° C. and lower than 35 ° C. The preheating temperature Tp can be calculated by the following equation, for example.

In the above case, the preheating temperature Tp = 20 ° C. is obtained from the above formula. In order to satisfy the condition of 25 ° C. <Tp <35 ° C., the preheating temperature Tp is set to a temperature higher than 25 ° C. .
In the present specification, the term “above” is not mathematically exact, and may include more than equal signs, or may not include equal signs. Similarly, the term “below” is not mathematically exact, and may include the following including an equal sign or may include less than an equal sign.
In step S80, the preheating temperature Tp calculated in step S78 is stored in the storage means 84. The preheating temperature Tp stored in this step is rewritten every time the operation process in the preheating mode is executed.

Steps S82 to S88 in FIG. 9 are the same processes as steps S30 to S36 shown in FIG.
In step S90, the auxiliary heat source inlet thermistor 502 detects the temperature Ti of the water sent from the intermediate height of the hot water storage tank 10. The detected temperature Ti is input to the controller 80. In the hot water storage type hot water supply system 2, in this step, instead of the temperature detected by the second tank thermistor 102, a judgment process is performed by comparing the temperature detected by the auxiliary heat source inlet thermistor 502 with the preheating reference temperature Tp. For example, when the position at which the second tank thermistor 102 is interposed is significantly lower than the connection position at the intermediate height of the hot water storage tank 10 in the auxiliary heating circulation path 50, the temperature detected by the auxiliary heat source inlet thermistor 502 It is possible to complete the preheating mode in a shorter time by judging in (1).
In step S92, it is determined whether or not the temperature Ti detected by the auxiliary heat source inlet thermistor 502 is equal to or higher than the preheating temperature Tp. When Ti is at a temperature higher than Tp (when the determination is YES), it is considered that water at an intermediate height from the upper part of hot water storage tank 10 has obtained a heat storage amount of at least Tp ° C., and the process proceeds to step S94. When Ti is lower than Tp (when the determination is NO), it is considered that there is not yet a sufficient heat storage amount in the water at the intermediate height from the upper part of hot water storage tank 10, and the process of step S90 is repeated.
Steps S94 to S96 in FIG. 9 are the same processes as steps S42 to S44 shown in FIG.
The processing from step S70 to step S96 is executed by the preheating mode execution means 86.

In the operation process in the preheating mode, the temperature (45 ° C. in the present embodiment) that is the determination criterion in step S76 may be selectable by the user along with the selection of whether or not to execute the preheating mode.
Further, the preheating temperature Tp calculated in step S78 is lower than the hot water supply set temperature Tα and higher than the temperature obtained by subtracting the temperature increase range of the water temperature obtained while passing the auxiliary heat source unit 60 from the hot water supply set temperature Tα. The temperature may be set in advance within a temperature range that satisfies the above.

( Reference example)
In FIG. 10, the figure showing schematic structure of the hot water storage type hot-water supply system 3 of a reference example is shown. In the following description, detailed description of the same components as those of the hot water storage hot water supply system 1 and the hot water storage hot water supply system 2 will be omitted.

The controller 81 in FIG. 10 includes a CPU 82, a storage unit 84, a heating amount determination unit 88, and a heating amount increase unit 89. The controller 81 stores various control programs (not shown). The heating amount determination means 88 is embodied by a control program for controlling the heating amount of the auxiliary heat source device 60 and the CPU 82. The heating amount increasing means 89 is embodied by a CPU 82 and a control program that executes control for increasing the heating amount of the auxiliary heat source unit 60 determined by the heating amount determining means 88 according to the conditions.
The controller 81 inputs an operation signal from the input unit 110, inputs signals from the various sensors described above, and controls the various pumps, valves, burners, and the like described above in accordance with a stored control program.
The input unit 110 includes a power switch 112 that outputs a system on signal and an off signal, and a hot water supply temperature setting unit 114 that outputs a set hot water supply set temperature. The input means 110 is operated by the user. An operation signal output from the input unit 110 is input to the controller 81.

(Hot water operation)
FIG. 11 shows a flowchart of the hot water supply operation. Steps S100 to S112 are the same processes as steps S50 to S62 shown in FIG.
In step S114, the combustion amount of the burner 68 is adjusted so that the temperature detected by the auxiliary heat source outlet thermistor 66 becomes 80 ° C. regardless of the hot water supply set temperature Tα. The amount of combustion of the burner 68 is controlled by the controller 81. The hot water that has passed through the auxiliary heat source unit 60 is heated to 80 ° C. and returned to the upper part of the hot water storage tank 10 through the auxiliary heating circulation path 50. The high-temperature water returned from the auxiliary heating circulation path 50 is mixed with water having a temperature lower than Tα ° C. in the upper part of the hot water storage tank 10 and sent out to the hot water supply path 40. The water sent to the hot water supply path 40 is adjusted to a hot water supply set temperature Tα by the mixing servo 38 and supplied. From the detected temperature of the hot water supply thermistor 302 and the temperature detected by the hot water supply thermistor 404, the opening degree of the mixing servo 38 is adjusted so that the detected temperature of the hot water supply thermistor 404 becomes the hot water supply set temperature Tα. In this step, the heating amount increasing unit 89 sets the heating amount of the auxiliary heat source unit 60 to a heating amount (80 in this reference example ) larger than the heating amount according to the hot water supply set temperature Tα (the heating amount determined by the heating amount determination unit 88). Since the amount of heating is in accordance with the temperature, and the combustion hot water supply operation is performed by increasing to 80 ° C.> hot water supply set temperature Tα), the temperature of the water sent to the hot water supply path 40 is set to the hot water supply set temperature Tα or more in a short time. It can be. It is possible to shorten the time until the water adjusted to the hot water supply set temperature Tα from the hot water tap 48 is supplied.
In step S116, the high temperature thermistor 402 detects the temperature Th of the water sent from the hot water storage tank 10 to the hot water supply path 40. The detected temperature Th is input to the controller 81.
In step S118, it is determined whether or not the detected temperature Th of the high temperature thermistor 402 is equal to or higher than the hot water supply set temperature Tα. When Th is equal to or greater than Tα (when the determination is YES), it is considered that there is no need to operate the auxiliary heat source device 60 by increasing the heating amount higher than the heating amount corresponding to the hot water supply set temperature Tα. In order to perform the combustion hot water supply operation with the heating amount according to Tα, the process proceeds to step S120. When Th is lower than Tα (when the determination is NO), it is considered that the heating amount of the auxiliary heat source device 60 needs to be increased to be higher than the heating amount according to the hot water supply set temperature Tα, and step S114 is performed. To S116 are repeated.
In step S120, the combustion amount of the burner 68 is controlled so that the detected temperature of the auxiliary heat source outlet thermistor 66 becomes Tα + 5 ° C. The amount of combustion of the burner 68 is controlled by the controller 81. The hot water that has passed through the auxiliary heat source device 60 is heated to Tα + 5 ° C. and returned to the hot water storage tank 10 through the auxiliary heating circulation path 50. Water slightly higher in temperature than Tα is sent from the upper part of the hot water storage tank 10 to the hot water supply path 40, adjusted to the hot water supply set temperature Tα by the mixing servo 38, and hot water is supplied. From the detected temperature of the hot water supply thermistor 302 and the detected temperature of the hot water supply thermistor 404, the opening degree of the mixing servo 38 is adjusted so that the detected temperature of the hot water supply thermistor 404 becomes the hot water supply set temperature Tα.

Steps S122 to S124 in FIG. 11 are the same processes as steps S66 to S68 shown in FIG.
The processing from step S100 to step S124 is executed by the heating amount determination means 88, the heating amount increase means 89, the CPU 82, and a control program that causes the CPU 82 to execute the processing from step S100 to step S124.

In the above processing, the heating amount of the auxiliary heat source device 60 that increases in step S114 increases to a heating amount that is larger than the heating amount determined by the heating amount determination means 88 (heating amount according to the hot water supply set temperature Tα). For example, when the hot water supply set temperature is 42 ° C., the temperature of the water returned through the auxiliary heat source unit is usually set to about 45 ° C., but in step S114, the heating amount increasing means 89 is used to use hot water. Water heated to a temperature higher than the necessary amount of heat (in this reference example , water heated to 80 ° C.) is returned to the hot water storage tank, mixed with water having a temperature lower than 42 ° C., and sent to the hot water supply path. In this embodiment, the amount of heating is increased by adjusting the combustion amount of the burner 68 so that the temperature detected by the auxiliary heat source outlet thermistor 66 is 80 ° C., but this is variable depending on the apparatus configuration to which this reference example is applied. It is not limited to 80 degreeC. For example, the heating amount of the auxiliary heat source device 60 can be increased so that the hot water supply set temperature is obtained when the water that has passed through the auxiliary heat source device 60 is mixed with the water in the upper part of the hot water storage tank 10.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, the preheating temperature Tp may be a temperature region. This configuration is useful when it is difficult to severely control the heating capacity of the auxiliary heat source machine due to the performance of the auxiliary heat source machine.
In addition to the factors exemplified in the embodiment, the preheating temperature is determined by the outside air temperature, the water supply temperature from the water supply, the size of the hot water storage tank, the heat dissipation loss rate, and the like. For this reason, the calculation formula which calculates preheating temperature is not limited to the illustration of a present Example.
The process for determining whether or not the preheating mode is executed may be determined by detecting the temperature of the upper part of the hot water storage tank every time a predetermined time elapses. For example, it is possible to further improve the convenience of the system by determining whether or not the preheating operation is performed early in the morning and completing the preheating operation as necessary before the use of hot water is started.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

It is a figure which represents the definition of preheating temperature notionally. It is a figure showing the temperature change of the upper part of a hot water storage tank. It is a figure showing the change of the heating amount of an auxiliary heat source machine. It is a figure showing the schematic structure of the hot water storage type hot water supply system 1 of 1st Example. It is a flowchart of the operation | movement outline | summary which switches the circulation path for auxiliary heating. It is a flowchart of the operation | movement outline | summary of preheating operation | movement. It is a flowchart of the operation | movement outline | summary at the time of hot water supply. It is a figure showing the schematic structure of the hot water storage type hot-water supply system 2 of 2nd Example. It is a flowchart of the operation | movement outline | summary of preheating operation | movement. It is a figure showing the schematic structure of the hot water storage type hot-water supply system 3 of a reference example. It is a flowchart of the operation | movement outline | summary at the time of hot water supply.

Explanation of symbols

1, 2, 3: Hot water storage system 10: Hot water storage tank 101: First tank thermistor 102: Second tank thermistor 103: Third tank thermistor 20: Heating circulation path 22: Circulation pump 24: Heat exchanger 26: Heat Exchanger 28: Three-way valve 29: Power generation unit bypass path 202: Thermistor 204: Thermistor 30: Water supply path 32: Pressure reducing valve 34: Water supply sensor 36: Water supply servo 38: Mixing servo 302: Water supply thermistor 40: Hot water supply path 42: Hot water Solenoid valve 44: Hot water supply sensor 46: Mixing path 48: Hot water tap 402: High temperature thermistor 404: Hot water thermistor 50: Auxiliary heating circulation path 52: Circulation pump 54: Auxiliary heating circulation flow rate servo 55: Open / close valve 56: Auxiliary heating Circulation branch path 58: on-off valve 502: auxiliary heat source inlet thermistor 504: auxiliary heating circulation flow rate Sensor 60: Auxiliary heat source machine 62: Latent heat exchanger 64: Sensible heat exchanger 66: Auxiliary heat source outlet thermistor 68: Burner 70: Power generation unit 72: Burner 74: Reformer 76: Fuel cell 702: Exhaust gas heat supply Path 704: Hydrogen gas supply path 706: Cooling water passage 80, 81: Controller 82: CPU
84: Storage means 86: Preheating mode execution means 88: Heating amount determination means 89: Heating amount increase means 92: Drain valve 90: Drainage path 110: Input means 112: Power switch 114: Hot water supply temperature setting means 115: Preheating mode execution selection switch

Claims (5)

A hot water storage tank,
A heating circulation path for returning the water in the lower part of the hot water tank to the upper part of the hot water tank,
Means for heating the water flowing through the heating circulation path;
A water supply route for supplying water to the lower part of the hot water storage tank;
A hot water supply path for leading the water in the upper part of the hot water storage tank to the hot water use point,
An auxiliary heating circulation path for returning water from the hot water tank to the upper part of the hot water tank,
An auxiliary heat source machine for heating the water flowing through the auxiliary heating circulation path;
Detection means for detecting the temperature of the upper part in the hot water storage tank;
Hot water supply temperature setting means for setting the temperature of the hot water led to the hot water use location;
A control device having a preheating mode for operating the auxiliary heat source so that the temperature detected by the detecting means is maintained at the preheating temperature;
The preheating temperature is lower than the hot water temperature set by the hot water temperature setting means, and is lower than the temperature obtained by subtracting the temperature increase range of the water temperature obtained while passing through the auxiliary heat source machine from the lowest temperature settable by the hot water temperature setting means. A hot water storage hot water system characterized by its high price.   The hot water storage system according to claim 1, wherein the preheating temperature is higher than a temperature obtained by subtracting a temperature increase range of the water temperature obtained while passing through the auxiliary heat source unit from the hot water supply temperature set by the hot water supply temperature setting means. Hot water system.   The hot water storage hot water supply system according to claim 1 or 2, wherein the temperature increase width is a temperature increase width in a minimum amount of water for operating the auxiliary heat source device.   The hot water storage type hot water supply system according to any one of claims 1 to 3, wherein the preheating mode is not executed when the hot water supply set temperature is higher than a predetermined temperature.   The hot water storage type hot water supply system according to any one of claims 1 to 3, further comprising operation switches for switching whether or not to execute the preheating mode.

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