JP7579754B2 - Connected hot water system - Google Patents

Description

The present invention relates to a connected hot water supply system.

Patent Document 1 discloses a linked hot water supply system including a plurality of hot water supply devices provided in parallel in a hot water supply circuit, and a number determination means for determining the number of the plurality of hot water supply devices in operation. Each of the plurality of hot water supply devices includes a heating source for heating hot water flowing through the hot water supply circuit, a flow rate detection means for detecting the flow rate of hot water flowing through the heating source, a switching valve for switching between a state allowing hot water to flow to the heating source and a state prohibiting it, and a control device for controlling the operation of the heating source and the switching valve. The number determination means is configured to determine whether to change the number of the plurality of hot water supply devices in operation one by one according to the flow rate detected by the flow rate detection means of each of the plurality of hot water supply devices.

JP 2007-315645 A

In the above linked hot water supply system, even if the flow rate of hot water flowing through the hot water supply circuit changes significantly, the number of operating hot water supply devices is changed one by one, so it takes a long time to realize the appropriate number of operating hot water supply devices. This specification provides technology that can quickly realize the appropriate number of operating hot water supply devices even if the flow rate of hot water flowing through the hot water supply circuit changes significantly.

This specification discloses a linked hot water supply system. The linked hot water supply system may include a plurality of hot water supply devices provided in parallel to a hot water supply circuit, a flow rate detection means for detecting the flow rate of hot water flowing through the hot water supply circuit, and a number determination means for determining the number of the plurality of hot water supply devices in operation. Each of the plurality of hot water supply devices may include a heat source for heating the hot water flowing through the hot water supply circuit, a switching valve for switching between a state in which hot water is permitted to flow to the heat source and a state in which hot water is prohibited to flow to the heat source, and a control device for controlling the operation of the heat source and the switching valve . The number determination means may determine to increase the number of the plurality of hot water supply devices in operation when a first predetermined condition is satisfied that the flow rate detected by the flow rate detection means exceeds an upper threshold. The upper threshold may be a value that increases as the number of the plurality of hot water supply devices in operation increases. The number determination means may determine to decrease the number of the plurality of hot water supply devices in operation when a second predetermined condition is satisfied that the flow rate detected by the flow rate detection means falls below a lower threshold. The lower threshold may be a value that increases as the number of the plurality of hot water supply devices in operation increases. In at least one of the cases where the number of units determination means decides to increase the number of operating units and where the number of units determination means decides to decrease the number of operating units, the number of units determination means may be configured to determine to change the number of operating units by an amount of change in number of units that is set in accordance with the rate of change of the flow rate detected by the flow rate detection means.

In the above-mentioned linked hot water supply system, when determining the number of hot water supply devices in operation, a decision is made to change the number of hot water supply devices in operation by an amount of change in the number of devices that is set according to the rate of change in the flow rate of hot water flowing through the hot water supply circuit. With this configuration, even if the flow rate of hot water flowing through the hot water supply circuit changes significantly, an appropriate number of hot water supply devices in operation can be quickly realized. Furthermore, with the above-mentioned configuration, when the flow rate of hot water flowing through the hot water supply circuit increases and it is determined that the capacity of the hot water supply devices in operation alone is insufficient, a decision can be made to increase the number of hot water supply devices in operation. At this time, when the flow rate of hot water flowing through the hot water supply circuit increases sharply, the number of hot water supply devices in operation is significantly increased, while when the flow rate of hot water flowing through the hot water supply circuit increases only slightly, the number of hot water supply devices in operation is slightly increased. Therefore, an appropriate number of hot water supply devices in operation can be quickly realized according to the degree of change in the flow rate of hot water flowing through the hot water supply circuit. Furthermore, in the above configuration, when the flow rate of hot water and water flowing through the hot water supply circuit decreases and it is determined that reducing the number of operating water heaters would improve the energy efficiency of the hot water supply circuit as a whole, a decision can be made to reduce the number of operating water heaters. In this case, if the flow rate of hot water and water flowing through the hot water supply circuit decreases suddenly, the number of operating water heaters is reduced significantly, whereas if the flow rate of hot water and water flowing through the hot water supply circuit decreases only slightly, the number of operating water heaters is reduced slightly. Therefore, an appropriate number of operating water heaters can be quickly achieved depending on the degree of change in the flow rate of hot water and water flowing through the hot water supply circuit.

The number of units determination means may be configured, when deciding to increase the number of operating units, to calculate the rate of change of the flow rate based on the elapsed time between when the flow rate exceeds a value smaller than the upper threshold by a predetermined flow rate and when the flow rate exceeds the upper threshold.

With the above configuration, the amount of change in the number of operating water heaters can be set according to the rate of change in the flow rate of hot water flowing through the hot water supply circuit immediately before a decision is made to change the number of operating water heaters. Therefore, even if the flow rate of hot water flowing through the hot water supply circuit suddenly changes, an appropriate number of operating water heaters can be quickly achieved.

The number of units determination means may be configured, when deciding to reduce the number of operating units, to calculate the rate of change of the flow rate based on the elapsed time between when the flow rate falls below a value that is a predetermined flow rate greater than the lower threshold value and when the flow rate falls below the lower threshold value.

With the above configuration, the amount of change in the number of operating water heaters can be set according to the rate of change in the flow rate of hot water flowing through the hot water supply circuit immediately before a decision is made to change the number of operating water heaters. Therefore, even if the flow rate of hot water flowing through the hot water supply circuit suddenly changes, an appropriate number of operating water heaters can be quickly achieved.

The number of units determination means may be configured, when deciding to increase the number of operating units, to calculate the rate of change of the flow rate based on the elapsed time from when a change in the flow rate detected by the flow rate detection means is detected until the first specified condition and/or the second specified condition is satisfied and the amount of change in the flow rate.

With the above configuration, the amount of change in the number of water heaters can be set according to the rate of change in the hot and cold water flow rate from immediately after the change in the hot and cold water flow rate begins until immediately before a decision is made to change the number of water heaters in operation. Therefore, an appropriate number of water heaters in operation can be achieved without being affected by short-term fluctuations in flow rate.

FIG. 1 is a diagram showing a configuration of a linked hot water supply system according to a first embodiment and a second embodiment. 1 is a diagram showing a configuration of a water heater 1 according to a first embodiment and a second embodiment. 4 is a flowchart showing a process for increasing the number of operating water heaters 1 executed by the connection unit 2 in the connected hot water supply system of Example 1. 11A to 11C are diagrams showing the gradient measurement period for the total flow rate of hot and cold water that changes at different flow rate change rates in the first embodiment. 4 is a flowchart showing a process for reducing the number of operating water heaters 1 executed by the connection unit 2 in the connected hot water supply system of Example 1. 13 is a flowchart showing a process for increasing the number of operating water heaters 1 executed by a connection unit 2 in a connected hot water supply system according to Example 2. 13A and 13B are diagrams showing the gradient measurement period for the total flow rate of hot and cold water that changes at different flow rate change rates in the second embodiment. 13 is a flowchart showing a process for reducing the number of operating water heaters 1 executed by a connection unit 2 in a connected hot water supply system according to Example 2.

Example 1
As shown in FIG. 1, the connected hot water supply system of this embodiment includes a plurality of hot water heaters 1, a connection unit 2, a water supply pipe 3a, a hot water supply pipe 3b, and a plurality of faucets 5.

Each water heater 1 is connected in parallel to the water supply pipe 3a and the hot water supply pipe 3b so that water is supplied from the water supply pipe 3a and hot water is sent to the hot water supply pipe 3b. Each faucet 5 is connected to the hot water supply pipe 3b, and each faucet 5 is configured to send the hot water supplied from the hot water supply pipe 3b to the outside.

The connection unit 2 is composed of a CPU, memory, etc. The connection unit 2 can communicate with the electrical unit 9 of each water heater 1 (details will be described later), and transmits the target hot water temperature to each water heater 1. The connection unit 2 also determines the number of water heaters 1 in operation based on the water supply information and flow rate information transmitted from the electrical unit 9 of each water heater 1, and transmits an operation start signal or an operation stop signal to each water heater 1. The connection unit 2 is configured not to transmit an operation stop signal when there is only one water heater 1 in a water supply possible state, so that all water heaters 1 do not stop operating. The connection unit 2 has a built-in timer, which can measure time and record the measured time.

As shown in FIG. 2, each water heater 1 includes a water supply pipe 3c that connects the water supply pipe 3a and the hot water supply pipe 3b to enable water to flow, a switching valve 7 that switches between an open state that allows water to be supplied to the water supply pipe 3c and a closed state that blocks the supply of water to the water supply pipe 3c, a flow rate sensor 6 that detects the flow rate of water flowing through the water supply pipe 3c, a heat exchanger 10 provided in the water supply pipe 3c, a gas burner 11 that heats the water flowing through the heat exchanger 10, a temperature sensor 8 that detects the temperature of the hot water heated by the heat exchanger 10, and an electrical unit 9 that has the function of controlling the operation of the gas burner 11 and the switching valve 7.

The electrical equipment unit 9 is composed of a CPU, memory, etc. The electrical equipment unit 9 controls the heat of the gas burner 11 so that the temperature of the hot water detected by the temperature sensor 8 becomes the hot water supply target temperature instructed by the connection unit 2. The electrical equipment unit 9 can communicate with the connection unit 2, and transmits to the connection unit 2 water supply information indicating the operating state of the switching valve 7 and flow rate information indicating the flow rate of water flowing through the water pipe 3c detected by the flow rate sensor 6. The water supply information is indicated by either a "water supply possible state" indicating that water can be supplied to the water pipe 3c by the switching valve 7, or a "water supply cut off state" indicating that the supply of water to the water pipe 3c is cut off by the switching valve 7.

The connection unit 2 calculates the sum of the hot and cold water flow rates (total flow rate) in each water heater 1 based on the flow rate information transmitted from the electrical unit 9 of each water heater 1. The total flow rate is equal to the flow rate of hot and cold water flowing through the water supply pipe 3a and the hot water supply pipe 3b.

Next, the process of increasing the number of operating water heaters 1 executed in the linked hot water supply system according to this embodiment will be described with reference to FIG.

In step 100, the connection unit 2 determines whether the total flow rate exceeds a preset gradient measurement start flow rate Q1. If the determination as to whether the total flow rate exceeds the gradient measurement start flow rate Q1 is negative, the process returns to step 100. If the determination as to whether the total flow rate exceeds the gradient measurement start flow rate Q1 is positive, the process proceeds to step 101. Note that the gradient measurement start flow rate Q1 is smaller than the gradient measurement end flow rate Q2 described below. For example, the gradient measurement start flow rate Q1 is a flow rate that is smaller than the gradient measurement end flow rate Q2 by a predetermined flow rate (e.g., 10 L/min).

In step 101, the connection unit 2 starts measuring time t on a timer built into the connection unit 2, setting t = 0, and proceeds to step 102.

In step 102, the connection unit 2 determines whether the total flow rate exceeds a preset gradient measurement end flow rate Q2. If the determination as to whether the total flow rate exceeds the gradient measurement end flow rate Q2 is negative, the process returns to step 102. If the determination as to whether the total flow rate exceeds the gradient measurement end flow rate Q2 is positive, the process proceeds to step 103. Note that the gradient measurement end flow rate Q2 is, for example, a flow rate that is 2 L/min smaller than the boundary flow rate between "medium" and "large" described below, multiplied by the number of water heaters 1 that are ready to supply water.

In step 103, the connection unit 2 stops the time measurement in the timer built into the connection unit 2, records the time t = T1, and proceeds to step 104.

In step 104, the connection unit 2 provisionally determines the number of water heaters 1 to be increased in relation to the number of operating units. Specifically, the connection unit 2 provisionally determines the number of water heaters 1 to be increased based on the flow rate of each water heater 1 that is in a water supply-enabled state. In this embodiment, the connection unit 2 classifies the flow rate of each water heater 1 into one of the preset stages of "large", "medium", or "small" based on the value of the flow rate of each water heater 1 that is in a water supply-enabled state. For example, when the flow rate of a certain water heater 1 is 14 L/min or more, the connection unit 2 classifies the flow rate of that water heater 1 into "large", when the flow rate of a certain water heater 1 is 6 L/min or more and less than 14 L/min, the connection unit 2 classifies the flow rate of that water heater 1 into "medium", and when the flow rate of a certain water heater 1 is 6 L/min or more and less than 14 L/min, the connection unit 2 classifies the flow rate of that water heater 1 into "small". The connection unit 2 then outputs the difference between the number of water heaters 1 that are in a state where they can supply water and that are classified as having a "large" flow rate, and the number of water heaters 1 that are classified as having a "small" flow rate. If this difference is 3 or more, the connection unit 2 provisionally determines that the number of water heaters 1 to be increased is 3; if this difference is 2, the connection unit 2 provisionally determines that the number of water heaters 1 to be increased is 2; if this difference is 1, the connection unit 2 provisionally determines that the number of water heaters 1 to be increased is 1.

In step 105a, the connection unit 2 determines whether the elapsed time T1 from the start of the gradient measurement to the end of the gradient measurement is less than the flow rate change rate determination index n1. If the determination of whether the elapsed time T1 is less than the flow rate change rate determination index n1 is affirmative, the process proceeds to step 106a.

In step 106a, the connection unit 2 corrects the number of water heaters 1 tentatively determined in step 104 to increase it by one, and confirms the increased number of water heaters 1.

If the determination in step 105a as to whether the elapsed time T1 is less than the flow rate change speed determination index n1 is negative, the process proceeds to step 105b. In step 105b, the connection unit 2 determines whether the elapsed time T1 is equal to or greater than the flow rate change speed determination index n1 and less than the flow rate change speed determination index n2. If the determination as to whether the elapsed time T1 is equal to or greater than the flow rate change speed determination index n1 and less than the flow rate change speed determination index n2 is positive, the process proceeds to step 106b. Note that the value of the flow rate change speed determination index n2 is greater than the value of the flow rate change speed determination index n1.

In step 106b, the connection unit 2 confirms the increased number of water heaters 1 without making any correction to the increased number of water heaters 1 tentatively determined in step 104.

If the determination in step 105b as to whether the elapsed time T1 is equal to or greater than the flow rate change rate determination index n1 and less than the flow rate change rate determination index n2 is negative, the process proceeds to step 105c. In step 105c, the connection unit 2 determines that the elapsed time T1 is equal to or greater than the flow rate change rate determination index n2, and the process proceeds to step 106c.

In step 106c, the connection unit 2 makes a correction to reduce the number of water heaters 1 tentatively determined in step 104 by one, and confirms the number of water heaters 1 to be increased.

After steps 106a, 106b, and 106c, the process proceeds to step 107. In step 107, the connection unit 2 transmits an operation start signal to the electrical units 9 of the water heaters 1 that are in a water supply cut-off state, for the confirmed number of additional water heaters 1, to open the switching valves 7.

As shown in FIG. 4, when the rate of change of the total flow rate is large (see the solid line in the figure), the elapsed time T11 from exceeding the gradient measurement start flow rate Q1 to exceeding the gradient measurement end flow rate Q2 is short. In such a case, the total flow rate increases sharply, so the appropriate number of operating water heaters 1 can be achieved by significantly increasing the number of operating water heaters 1. In contrast, when the rate of change of the total flow rate is small (see the dashed line in the figure), the elapsed time T12 from exceeding the gradient measurement start flow rate Q1 to exceeding the gradient measurement end flow rate Q2 is long. In such a case, the total flow rate has only increased slightly, so the appropriate number of operating water heaters 1 can be achieved by slightly increasing the number of operating water heaters 1. According to the process shown in FIG. 3, in the process of steps 105a, 105b, 105c, 106a, 106b, and 106c, if the elapsed time T1 from exceeding the gradient measurement start flow rate Q1 to exceeding the gradient measurement end flow rate Q2 is short (if it is less than the flow rate change rate determination index n1), the number of water heaters 1 increased is increased, and if the elapsed time T1 is long (if it is equal to or greater than the flow rate change rate determination index n2), the number of water heaters 1 increased is decreased, thereby quickly achieving an appropriate number of operating water heaters 1.

Next, using FIG. 5, we will explain the process of reducing the number of operating water heaters 1 executed in the connected hot water supply system according to this embodiment.

In step 150, the connection unit 2 determines whether the total flow rate is below a preset gradient measurement start flow rate Q3. If the determination of whether the total flow rate is below the gradient measurement start flow rate Q3 is negative, the process returns to step 150. If the determination of whether the total flow rate is below the gradient measurement start flow rate Q3 is positive, the process proceeds to step 151. Note that the gradient measurement start flow rate Q3 is smaller than the gradient measurement start flow rate Q1 and larger than the gradient measurement end flow rate Q4 described below. For example, the gradient measurement start flow rate Q3 is a flow rate that is larger than the gradient measurement end flow rate Q4 by a predetermined flow rate (e.g., 10 L/min).

In step 151, the connection unit 2 starts measuring time t on the timer built into the connection unit 2, setting it to t = 0, and proceeds to step 152.

In step 152, the connection unit 2 determines whether the total flow rate is below a preset gradient measurement end flow rate Q4. If the determination as to whether the total flow rate is below the gradient measurement end flow rate Q4 is negative, the process returns to step 152. If the determination as to whether the total flow rate is below the gradient measurement end flow rate Q4 is positive, the process proceeds to step 153. Note that the gradient measurement end flow rate Q4 is, for example, a flow rate that is 2 L/min greater than the boundary flow rate between "small" and "medium" multiplied by the number of water heaters 1 that are ready to supply water.

In step 153, the connection unit 2 stops the time measurement in the timer built into the connection unit 2, records the time t = T10, and proceeds to step 154.

In step 154, the connection unit 2 provisionally determines the number of water heaters 1 to be reduced in operation. Specifically, the connection unit 2 provisionally determines the number of water heaters 1 to be reduced based on the flow rate of each of the water heaters 1 that are in a state where water can be supplied. In this embodiment as well, the connection unit 2 outputs the difference between the number of water heaters 1 that are in a state where water can be supplied and that are classified as having a "small" flow rate, and the number of water heaters 1 that are classified as having a "large" flow rate. If this difference is 3 or more, the connection unit 2 provisionally determines the number of water heaters 1 to be reduced to 3, if this difference is 2, the connection unit 2 provisionally determines the number of water heaters 1 to be reduced to 2, and if this difference is 1, the connection unit 2 provisionally determines the number of water heaters 1 to be reduced to 1.

In step 155a, the connection unit 2 determines whether the elapsed time T10 from the start of the gradient measurement to the end of the gradient measurement is less than the flow rate change rate determination index n3. If the determination of whether the elapsed time T10 is less than the flow rate change rate determination index n3 is affirmative, the process proceeds to step 156a.

In step 156a, the connection unit 2 corrects the number of water heaters 1 tentatively determined in step 154 to be reduced by one, and confirms the number of water heaters 1 to be reduced.

If the determination in step 155a as to whether the elapsed time T10 is less than the flow rate change speed determination index n3 is negative, the process proceeds to step 155b. In step 155b, the connection unit 2 determines whether the elapsed time T10 is equal to or greater than the flow rate change speed determination index n3 and less than the flow rate change speed determination index n4. If the determination as to whether the elapsed time T10 is equal to or greater than the flow rate change speed determination index n3 and less than the flow rate change speed determination index n4 is positive, the process proceeds to step 156b. Note that the value of the flow rate change speed determination index n4 is greater than the value of the flow rate change speed determination index n3.

In step 156b, the connection unit 2 confirms the number of water heaters 1 to be reduced without making any correction to the number of water heaters 1 tentatively determined in step 154.

If the determination in step 155b as to whether the elapsed time T10 is equal to or greater than the flow rate change rate determination index n3 and less than the flow rate change rate determination index n4 is negative, the process proceeds to step 155c. In step 155c, the connection unit 2 determines that the elapsed time T10 is equal to or greater than the flow rate change rate determination index n4, and the process proceeds to step 156c.

In step 156c, the connection unit 2 corrects the number of water heaters 1 tentatively determined in step 154 to be reduced by one, and confirms the reduced number of water heaters 1.

After steps 156a, 156b, and 156c, the process proceeds to step 157. In step 157, the connection unit 2 transmits an operation stop signal to close the switching valve 7 to the electrical units 9 of the water heaters 1 that are in a state where they can supply water, for the determined number of water heaters 1 that have been reduced.

According to the process shown in FIG. 5, in the process of steps 155a, 155b, 155c, 156a, 156b, and 156c, if the elapsed time T10 from when the flow rate falls below the gradient measurement start flow rate Q3 until when the flow rate falls below the gradient measurement end flow rate Q4 is short (if it is less than the flow rate change rate determination index n3), the number of water heaters 1 that are reduced is increased, and if the elapsed time T10 is long (if it is equal to or greater than the flow rate change rate determination index n4), the number of water heaters 1 that are reduced is decreased, thereby enabling an appropriate number of water heaters 1 in operation to be quickly achieved.

Example 2
The linked hot water supply system according to this embodiment has a similar configuration to the linked hot water supply system according to the first embodiment shown in Figs.

Next, the process of increasing the number of operating water heaters 1 executed in the linked hot water supply system according to this embodiment will be described with reference to FIG. 6.

In step 200, the connection unit 2 determines whether a flow rate change is detected in the total flow rate. In the process of increasing the number of water heaters 1 in operation executed in the connected hot water supply system according to this embodiment, the connection unit 2 determines whether the total flow rate has started to rise (the total flow rate has transitioned from a steady state to a state of transient increase). If the determination of whether a flow rate change is detected is negative, the process returns to step 200. If the determination of whether a flow rate change is detected is positive, the process proceeds to step 201. Note that the steady state referred to here is, for example, a state in which the difference between the total flow rate immediately after a very short period and the total flow rate immediately before, and the difference between the total flow rate immediately before the very short period and the total flow rate immediately after, do not exceed a predetermined value , and this state continues for a certain period of time. That is, the connection unit 2 determines whether the rise of the total flow rate has started by determining whether the difference between the total flow rate immediately after the short period and the total flow rate immediately before exceeds a predetermined value . The predetermined value is, for example, 10% of the total flow rate immediately before the short period.

In step 201, the connection unit 2 starts measuring time t on a timer built into the connection unit 2, setting t = 0, and proceeds to step 202.

In step 202, the connection unit 2 records the total flow rate at t=0 (start-of-rise flow rate Q21) and proceeds to step 203.

In step 203, the connection unit 2 determines whether the total flow rate exceeds a preset gradient measurement end flow rate Q22. If the determination as to whether the total flow rate exceeds the gradient measurement end flow rate Q22 is negative, the process returns to step 203. If the determination as to whether the total flow rate exceeds the gradient measurement end flow rate Q22 is positive, the process proceeds to step 204. Note that the gradient measurement end flow rate Q22 is, for example, a flow rate that is 2 L/min smaller than the boundary flow rate between "medium" and "large" described below, multiplied by the number of water heaters 1 that are ready to supply water.

In step 204, the connection unit 2 stops the time measurement in the timer built into the connection unit 2, records the time t = T2, and proceeds to step 205.

In step 205, the connection unit 2 provisionally determines the number of operating water heaters 1 to be increased. The connection unit 2 provisionally determines the number of operating water heaters 1 to be increased in the same manner as in Example 1 (see step 104 in FIG. 3).

In step 206, the connection unit 2 calculates the flow rate change rate X of the total flow rate from the rise start flow rate Q21 and the gradient measurement end flow rate Q22 recorded in step 202, and the elapsed time T2 from the rise start to the gradient measurement end recorded in step 204. Specifically, the connection unit 2 calculates the flow rate change rate X of the total flow rate as X = (Q22 - Q21) / T2.

In step 207a, the connection unit 2 determines whether the flow rate change rate X of the total flow rate obtained in step 206 is less than the flow rate change rate determination index n21. If the determination of whether the flow rate change rate X of the total flow rate is less than the flow rate change rate determination index n21 is affirmative, the process proceeds to step 208a.

In step 208a, the connection unit 2 corrects the number of water heaters 1 tentatively determined in step 205 to decrease by one, and confirms the number of water heaters 1 to be increased.

In step 207a, if the determination as to whether the flow rate change rate X of the total flow rate is less than the flow rate change rate determination index n21 is negative, the process proceeds to step 207b. In step 207b, the connection unit 2 determines whether the flow rate change rate X of the total flow rate is equal to or greater than the flow rate change rate determination index n21 and less than the flow rate change rate determination index n22. If the determination as to whether the flow rate change rate X of the total flow rate is equal to or greater than the flow rate change rate determination index n21 and less than the flow rate change rate determination index n22 is positive, the process proceeds to step 208b. The value of the flow rate change rate determination index n22 is greater than the flow rate change rate determination index n21.

In step 208b, the connection unit 2 confirms the increased number of water heaters 1 without making any correction to the increased number of water heaters 1 tentatively determined in step 205.

If the determination in step 207b as to whether the flow rate change rate X of the total flow rate is equal to or greater than the flow rate change rate determination index n21 and less than the flow rate change rate determination index n22 is negative, the process proceeds to step 207c. In step 207c, the connection unit 2 determines that the flow rate change rate X of the total flow rate is equal to or greater than the flow rate change rate determination index n22, and the process proceeds to step 208c.

In step 208c, the connection unit 2 corrects the number of water heaters 1 tentatively determined in step 205 to increase by one, and confirms the increased number of water heaters 1.

After steps 208a, 208b, and 208c, the process proceeds to step 209. In step 209, the connection unit 2 transmits an operation start signal to the electrical units 9 of the water heaters 1 that are in a water supply cut-off state, for the confirmed number of additional water heaters 1, to open the switching valves 7.

7, when the flow rate change rate X of the total flow rate is large (see the solid line in the figure), the elapsed time T21 from when the total flow rate starts to rise until it exceeds the gradient measurement end flow rate Q22 is short. In such a case, since the total flow rate has increased sharply from the steady state, the appropriate number of operating water heaters 1 can be realized by significantly increasing the number of operating water heaters 1. In contrast, when the flow rate change rate X of the total flow rate is small (see the dashed line in the figure), the elapsed time T22 from when the total flow rate starts to rise until it exceeds the gradient measurement end flow rate Q22 is long. In such a case, since the total flow rate has only increased slightly from the steady state, the appropriate number of operating water heaters 1 can be realized by slightly increasing the number of operating water heaters 1. According to the process shown in FIG. 6, in the process of steps 207a, 207b, 207c, 208a, 208b, and 208c, if the flow rate change rate X of the total flow rate is small (if it is less than the flow rate change rate judgment index n21), the number of water heaters 1 to be increased is reduced, and if the flow rate change rate X of the total flow rate is large (if it is equal to or greater than the flow rate change rate judgment index n22), the number of water heaters 1 to be increased is increased, thereby quickly achieving an appropriate number of operating water heaters 1.

Next, the process of reducing the number of operating water heaters 1 executed in the linked hot water supply system according to this embodiment will be described with reference to FIG.

In step 250, the connection unit 2 determines whether a flow rate change is detected in the total flow rate. In the process of reducing the number of water heaters 1 in operation executed in the connected hot water supply system according to this embodiment, the connection unit 2 determines whether the total flow rate has started to fall (the total flow rate has transitioned from a steady state to a state of transient reduction). If the determination of whether a flow rate change is detected is negative, the process returns to step 250. If the determination of whether a flow rate change is detected is positive, the process proceeds to step 251. The steady state is, for example, a state in which the difference between the total flow rate immediately after a very short period and the total flow rate immediately before, and the difference between the total flow rate immediately before and the total flow rate immediately after the very short period do not exceed a predetermined value , and this state continues for a certain period of time. That is, the connection unit 2 determines whether the difference between the total flow rate immediately before the short period and the total flow rate immediately after exceeds a predetermined value , thereby determining whether the total flow rate has started to fall. The predetermined value is, for example, 10% of the total flow rate immediately before the short period.

In step 251, the connection unit 2 starts measuring time t on the timer built into the connection unit 2, setting t = 0, and proceeds to step 252.

In step 252, the connection unit 2 records the total flow rate at t=0 (the falling start flow rate Q23) and proceeds to step 253.

In step 253, the connection unit 2 determines whether the total flow rate is below a preset gradient measurement end flow rate Q24. If the determination as to whether the total flow rate is below the gradient measurement end flow rate Q24 is negative, the process returns to step 253. If the determination as to whether the total flow rate is below the gradient measurement end flow rate Q24 is positive, the process proceeds to step 254. Note that the gradient measurement end flow rate Q24 is, for example, a flow rate that is 2 L/min greater than the boundary flow rate between "small" and "medium" multiplied by the number of water heaters 1 that are ready to supply water.

In step 254, the connection unit 2 stops the time measurement in the timer built into the connection unit 2, records the time t = T20, and proceeds to step 255.

In step 255, the connection unit 2 provisionally determines the number of operating water heaters 1 to be reduced. The connection unit 2 provisionally determines the number of operating water heaters 1 to be reduced in the same manner as in Example 1 (see step 154 in FIG. 5).

In step 256, the connection unit 2 calculates the flow rate change rate X0 of the total flow rate from the fall start flow rate Q23 and the gradient measurement end flow rate Q24 recorded in step 252, and the elapsed time T20 from the fall start to the gradient measurement end recorded in step 254. Specifically, the connection unit 2 calculates the flow rate change rate X0 of the total flow rate as X0 = (Q23 - Q24) / T20.

In step 257a, the connection unit 2 determines whether the flow rate change rate X0 of the total flow rate obtained in step 256 is less than the flow rate change rate determination index n23. If the determination of whether the flow rate change rate X0 of the total flow rate is less than the flow rate change rate determination index n23 is affirmative, the process proceeds to step 258a.

In step 258a, the connection unit 2 corrects the number of water heaters 1 tentatively determined in step 255 to be reduced by one, and confirms the reduced number of water heaters 1.

If the determination in step 257a as to whether the flow rate change rate X0 of the total flow rate is less than the flow rate change rate determination index n23 is negative, the process proceeds to step 257b. In step 257b, the connection unit 2 determines whether the flow rate change rate X0 of the total flow rate is equal to or greater than the flow rate change rate determination index n23 and less than the flow rate change rate determination index n24. If the determination as to whether the flow rate change rate X0 of the total flow rate is equal to or greater than the flow rate change rate determination index n23 and less than the flow rate change rate determination index n24 is positive, the process proceeds to step 258b. Note that the value of the flow rate change rate determination index n24 is greater than the flow rate change rate determination index n23.

In step 258b, the connection unit 2 confirms the number of water heaters 1 to be reduced without making any correction to the number of water heaters 1 tentatively determined in step 255.

If the determination in step 257b as to whether the flow rate change rate X0 of the total flow rate is equal to or greater than the flow rate change rate determination index n23 and less than the flow rate change rate determination index n24 is negative, the process proceeds to step 257c. In step 257c, the connection unit 2 determines that the flow rate change rate X0 of the total flow rate is equal to or greater than the flow rate change rate determination index n24, and the process proceeds to step 258c.

In step 258c, the connection unit 2 corrects the number of water heaters 1 tentatively determined in step 255 to be reduced by one, and confirms the number of water heaters 1 to be reduced.

After steps 258a, 258b, and 258c, the process proceeds to step 259. In step 259, the connection unit 2 transmits an operation stop signal to close the switching valve 7 to the electrical unit 9 of the water heater 1 that is in a state where water can be supplied, for the determined number of reduced water heaters 1.

According to the process shown in FIG. 8, in the process of steps 257a, 257b, 257c, 258a, 258b, and 258c, if the flow rate change rate X0 of the total flow rate is small (if it is less than the flow rate change rate judgment index n23), the number of water heaters 1 to be reduced is reduced, and if the flow rate change rate X0 of the total flow rate is large (if it is equal to or greater than the flow rate change rate judgment index n24), the number of water heaters 1 to be reduced is increased, thereby enabling an appropriate number of water heaters 1 in operation to be quickly achieved.

(Modification)
The values of the gradient measurement start flow rate Q1, the gradient measurement end flow rate Q2, the gradient measurement start flow rate Q3, the gradient measurement end flow rate Q4, the gradient measurement end flow rate Q22, and the gradient measurement end flow rate Q24 can be changed as appropriate.

The values of flow rate change rate determination index n1, flow rate change rate determination index n2, flow rate change rate determination index n3, flow rate change rate determination index n4, flow rate change rate determination index n21, flow rate change rate determination index n22, flow rate change rate determination index n23, and flow rate change rate determination index n24 may be changed as appropriate.

The flow rate ranges "large", "medium" and "small" can be changed as appropriate.

The water supply pipe 3a or the hot water supply pipe 3b may be equipped with a flow sensor, and the connection unit 2 may use the flow rate detected by this flow sensor as the total flow rate.

As described above, in one or more embodiments, the connected hot water supply system includes a plurality of water heaters 1 arranged in parallel with the water supply pipe 3a and the hot water supply pipe 3b, a flow sensor 6 and a connection unit 2 (or a flow sensor provided in the water supply pipe 3a or the hot water supply pipe 3b) in each water heater 1 that detects the total flow rate of hot water flowing through the water supply pipe 3a and the hot water supply pipe 3b, and a connection unit 2 that determines the number of operating units of the plurality of water heaters 1. Each of the plurality of water heaters 1 includes a gas burner 11 that heats the water flowing through the water supply pipe 3a and the hot water supply pipe 3b, a switching valve 7 that switches between an open state that allows water to flow to the gas burner 11 and a closed state that prohibits water flow, and an electrical unit 9 that controls the operation of the gas burner 11 and the switching valve 7. The connection unit 2 is configured to determine the number of operating units of the plurality of water heaters 1 to be changed by an amount of change in the number that is set according to the rate of change in the total flow rate of hot water flowing through the water supply pipe 3a and the hot water supply pipe 3b when a predetermined condition is satisfied.

In the above linked hot water supply system, when determining the number of operating water heaters 1, the number of operating water heaters 1 is changed by an amount of change in the number that is set according to the rate of change in the total flow rate, so that an appropriate number of operating water heaters 1 can be quickly achieved even if the total flow rate changes significantly.

In one or more embodiments, the specified condition includes a condition that the total flow rate detected by the flow sensor 6 in each water heater 1 and the connecting unit 2 (or the flow sensor provided in the water supply pipe 3a or the hot water supply pipe 3b) exceeds the gradient measurement end flow rate Q2 (or the gradient measurement end flow rate Q22), and the connecting unit 2 is configured to make a decision to increase the number of operating water heaters 1 when the total flow rate exceeds the gradient measurement end flow rate Q2 (or the gradient measurement end flow rate Q22).

In the above configuration, when the total flow rate increases and it is determined that the capacity of the operating water heaters 1 alone is insufficient, a decision can be made to increase the number of operating water heaters 1. At this time, if the total flow rate increases suddenly, the number of operating water heaters 1 is increased significantly, whereas if the total flow rate has only increased slightly, the number of operating water heaters 1 is increased slightly. Therefore, an appropriate number of operating water heaters 1 can be quickly achieved depending on the degree of change in the total flow rate.

In one or more embodiments, the specified condition includes a condition that the total flow rate detected by the flow sensor 6 in each water heater 1 and the connecting unit 2 (or the flow sensor provided in the water supply pipe 3a or the hot water supply pipe 3b) falls below the gradient measurement end flow rate Q4 (gradient measurement end flow rate Q24), and the connecting unit 2 is configured to decide to reduce the number of operating water heaters 1 when the total flow rate falls below the gradient measurement end flow rate Q4 (gradient measurement end flow rate Q24).

In the above configuration, when the total flow rate decreases and it is determined that reducing the number of operating water heaters 1 would improve the energy efficiency of the hot water circuit as a whole, a decision can be made to reduce the number of operating water heaters 1. At this time, if the total flow rate decreases suddenly, the number of operating water heaters 1 is reduced significantly, whereas if the total flow rate has only decreased slightly, the number of operating water heaters 1 is reduced slightly. Therefore, an appropriate number of operating water heaters 1 can be quickly achieved depending on the degree of change in the total flow rate.

In one or more embodiments, the connection unit 2 is configured to calculate the rate of change of the total flow rate based on the elapsed time T1 between exceeding the gradient measurement start flow rate Q1 and exceeding the gradient measurement end flow rate Q2.

According to the above configuration, the amount of change in the number of water heaters 1 in operation can be set according to the rate of change in the total flow rate immediately before the decision to change the number of water heaters 1 in operation is made. Therefore, even if the total flow rate changes suddenly, an appropriate number of water heaters 1 in operation can be quickly achieved.

In one or more embodiments, the connection unit 2 is configured to calculate the rate of change of the total flow rate based on the elapsed time T10 between when the total flow rate falls below the gradient measurement start flow rate Q3 and when the total flow rate falls below the gradient measurement end flow rate Q4.

According to the above configuration, the amount of change in the number of water heaters 1 in operation can be set according to the rate of change in the total flow rate immediately before the decision to change the number of water heaters 1 in operation is made. Therefore, even if the total flow rate changes suddenly, an appropriate number of water heaters 1 in operation can be quickly achieved.

In one or more embodiments, the connection unit 2 is configured to calculate the flow rate change rate X (or X0) of the total flow rate based on the elapsed time T2 (or T20) from when a change in the total flow rate detected by the flow sensor 6 in each water heater 1 and the connection unit 2 (or a flow sensor provided in the water supply pipe 3a or hot water supply pipe 3b) is detected until the total flow rate exceeds the gradient measurement end flow rate Q22 (or falls below the gradient measurement end flow rate Q24) and the difference between the gradient measurement end flow rate Q22 (or gradient measurement end flow rate Q24) and the rise start flow rate Q21 (or fall start flow rate Q23).

According to the above configuration, the amount of change in the number of water heaters 1 can be set according to the rate of change X (or X0) of the total flow rate from immediately after the total flow rate starts to change until immediately before a decision is made to change the number of water heaters 1 in operation. Therefore, an appropriate number of water heaters 1 in operation can be achieved without being affected by short-term fluctuations in the flow rate.

Although the embodiments have been described in detail above, they are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples given above. The technical elements described in this specification or drawings are technically useful either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful.

1: Water heater 2: Connection unit 3a: Water supply pipe 3b: Hot water supply pipe 3c: Water supply pipe 5: Faucet 6: Flow rate detection means 7: Switching valve 8: Temperature sensor 9: Electrical unit 10: Heat exchanger 11: Gas burner Q1: Gradient measurement start flow rate Q2: Gradient measurement end flow rate Q21: Rise start flow rate Q22: Gradient measurement end flow rate Q23: Fall start flow rate Q24: Gradient measurement end flow rate Q3: Gradient measurement start flow rate Q4: Gradient measurement end flow rate X: Flow rate of change of total flow rate X0: Flow rate of change of total flow rate n1: Flow rate of change judgment index n2: Flow rate of change judgment index n3: Flow rate of change judgment index n4: Flow rate of change judgment index n21: Flow rate of change judgment index n22: Flow rate of change judgment index n23: Flow rate of change judgment index n24: Flow rate of change judgment index

Claims (5)

A plurality of hot water supply devices provided in parallel in a hot water supply circuit;
A flow rate detection means for detecting a flow rate of hot water flowing through the hot water supply circuit;
A connected hot water supply system including a number determination means for determining the number of operation of the plurality of hot water supply devices,
Each of the plurality of hot water supply devices is
A heat source that heats the hot water flowing through the hot water supply circuit;
a switching valve that switches between a state in which hot water is permitted to flow to the heating source and a state in which hot water is prohibited to flow to the heating source;
A control device is provided for controlling the operation of the heat source and the switching valve,
the number determination means determines to increase the number of the hot water heating apparatuses in operation when a first predetermined condition is satisfied, that is, the flow rate detected by the flow rate detection means exceeds an upper threshold value;
The upper threshold value is a value that increases as the number of operating vehicles increases,
the number determination means determines to reduce the number of the hot water heating apparatuses in operation when a second predetermined condition is satisfied, that is, the flow rate detected by the flow rate detection means is lower than a lower threshold value;
The lower threshold value is a value that increases as the number of operating vehicles increases,
A linked hot water supply system, wherein in at least one of the cases where the number of units determination means decides to increase the number of operating units and where the number of units determination means decides to decrease the number of operating units, the number of units determination means is configured to determine to change the number of operating units by an amount of change in the number of units that is set in accordance with the rate of change of the flow rate detected by the flow rate detection means. The connected hot water supply system of claim 1, wherein the number determination means is configured to, when deciding to increase the number of operating units, calculate the rate of change of the flow rate based on the elapsed time between when the flow rate exceeds a value that is a predetermined flow rate smaller than the upper threshold value and when the flow rate exceeds the upper threshold value. The connected hot water supply system of claim 1, wherein the number determination means is configured to, when deciding to reduce the number of operating units, calculate the rate of change of the flow rate based on the elapsed time between when the flow rate falls below a value that is a predetermined flow rate greater than the lower threshold value and when the flow rate falls below the lower threshold value. The connected hot water supply system of claim 1 , wherein the number determination means is configured to, when deciding to increase the number of operating units, calculate the rate of change of the flow rate based on the elapsed time between when the change in the flow rate detected by the flow detection means is detected and when the first specified condition is satisfied and the amount of change in the flow rate. The connected hot water supply system of claim 1 , wherein the number determination means is configured to, when deciding to reduce the number of operating units, calculate the rate of change of the flow rate based on the elapsed time between when the change in the flow rate detected by the flow detection means is detected and when the second specified condition is satisfied and the amount of change in the flow rate.

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