Hot water system

Abstract

To provide a hot water system which does not cause a situation where the temperature of hot water changes due to the shortage of hot water amount in a tank during a hot water supply operation in a bathroom even when the tank is miniaturized.SOLUTION: A controller 4 detects a use amount and / or a flow rate of hot water for a predetermined learning period by a hot water tapping flow rate sensor 17, associates a detection result with detection time and stores it as learning data in storage means, and refers to the learning data and learns the bathroom use time zone during which hot water is used in the bathroom. Then, in the case of supplying hot water in the bathroom use time zone, it controls a switching solenoid valve 16 and stops the use of hot water in a tank 1, and switches so as to supply tap water directly from a water supply pipe 15 to a water heater 3 side, and supplies the tap water to a bathtub 41 after igniting a hot water supply burner 22 and heating the tap water in the water heater 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a hybrid hot water supply system comprising a hot water heater equipped with a burner and capable of heating passing water, and a tank equipped with a heat pump and storing the heated hot water. [Background technology]

[0002] Conventionally, a heat pump-type hot water supply system has been put into practical use, which includes a heat pump and a tank for storing hot water heated by the heat pump, and supplies hot water in the tank to a kitchen, a bathroom, etc. However, in the conventional heat pump-type hot water supply system, there is a problem that the tank must be very large in size in order to store a large amount of hot water required when filling a bathtub. Therefore, as described in Patent Document 1, for example, a hybrid hot water supply system has been devised in which a burner heating device, which is a hot water heater, is installed in the supply path downstream of the tank in which the hot water is stored. In the hybrid hot water supply system described in Patent Document 1, if the amount of hot water in the tank is low when filling the bathtub, the burner heating device is operated in addition to heating by the heat pump to make up for the lack of hot water, and as a result, the tank can be made smaller. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-224762 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the hot water supply system described in Patent Document 1, the tank in which hot water is stored can be made smaller. However, when the tank is made smaller, it is easy for the amount of hot water in the tank to be insufficient during hot water supply operations in the bathroom, where a large amount of hot water is used, particularly for filling the bathtub and using the shower. When the amount of hot water in the tank becomes insufficient, the burner heating device is activated as described above to make up for the lack of hot water. However, if the burner heating device is activated only after detecting that the amount of hot water in the tank is insufficient, the temperature of the hot water being dispensed becomes unstable. This can lead to situations where the temperature of the hot water changes while the shower is in use, which can cause discomfort to the user.

[0005] Therefore, the present invention has been made in consideration of the above problems, and aims to provide a hot water supply system that prevents a situation in which the water temperature changes due to insufficient hot water in the tank during hot water supply operation in the bathroom, even if the tank is made smaller. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a hot water supply system comprising a tank for storing hot water, a heat pump for heating the hot water in the tank, a water heater for heating the supplied hot water using the heat of combustion of fuel gas, a plurality of supply paths for supplying hot water to points of use, including a first supply path for supplying the hot water in the tank to a specified point of use, and a second supply path for heating tap water in the water heater without going through the tank and then supplying it to the point of use, and a control means for controlling the operation of the water heater and the selection of the supply paths, wherein the point of use includes a bathroom, while the system is also equipped with a flow detection means for detecting the flow rate of hot water in the supply path, and a learning means for storing the hot water usage status based on the detection results by the flow detection means in association with time as a usage history, and for learning the bathroom usage time periods when hot water is used in the bathroom based on the usage history, and wherein when hot water is supplied to the point of use during the bathroom usage time periods, the control means does not use the hot water stored in the tank, but supplies hot water to the point of use via the second supply path. Effect of the Invention

[0007] According to the present invention, the hot water supply system includes a bathroom as a place of use, and includes a flow rate detection means for detecting the flow rate of hot water in the supply path, a learning means for storing the hot water usage status based on the detection result by the flow rate detection means in association with time as a usage history, and for learning the bathroom usage time period when hot water is used in the bathroom based on the usage history. When supplying hot water to the place of use during the bathroom usage time period, the control means does not use the hot water stored in the tank, but supplies hot water to the place of use via the second supply path. Therefore, even if the tank is made small, a situation will not occur where the amount of hot water in the tank is insufficient during hot water supply operation in the bathroom, and therefore a hot water supply system will not occur where the temperature of hot water changes during hot water supply operation in the bathroom. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram showing an outline of a hot water supply system. [Diagram 2] This is a table showing the start time of hot water supply, the amount of hot water produced, etc. for a standard four-person household. [Diagram 3] 4 is a flowchart showing control related to hot water supply operation by a controller. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hot water supply system according to an embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory diagram showing an outline of a hot water supply system S. As shown in FIG. The hot water supply system S comprises a tank 1 for storing hot water, a heat pump 2 for heating the hot water in the tank 1, a water heater 3 for heating the supplied hot water by burning a fuel gas, a controller 4, and a remote control 5. The capacity of the tank 1 is 20 L, which is sufficiently smaller than the capacity of a typical bathtub 41. A water supply pipe 6 connected to an external water pipe is also connected to the tank 1. The heat pump 2 is a known device that includes an evaporator, a compressor, a heat exchanger, etc., and heats the passing water by heat exchange between a heat medium and the passing water, and has an output of 2.0 kW.

[0010] A tank forward pipe 7 is connected between the top of the tank 1 and the outlet of the heat pump 2, and a tank return pipe 8 is connected between the bottom of the tank 1 and the inlet of the heat pump 2. The tank forward pipe 7 and the tank return pipe 8 form a circulation path 9 in which hot water circulates between the tank 1 and the heat pump 2. The tank return pipe 8 is provided with a pump 10 for circulating hot water and a return temperature thermistor 11 for detecting the temperature of the hot water in the tank return pipe 8. The upper part of the tank 1 is connected to a relay pipe 12 connected to a hot water heat exchanger 23 of the water heater 3 described later. The relay pipe 12 is provided with a relay temperature thermistor 13 for detecting the temperature of the hot water flowing in the relay pipe 12 and a relay flow rate sensor 14 for detecting the flow rate of the hot water flowing in the relay pipe 12. A direct water supply pipe 15 is connected between a point on the relay pipe 12 upstream of the water heater 3 and the water supply pipe 6 to bypass the tank 1 and directly supply water in the water supply pipe 6 to the water heater 3 side. Furthermore, a switching solenoid valve 16 is provided at the connection between the relay pipe 12 and the direct water supply pipe 15, which can switch between supplying hot water in the tank 1 to the hot water heat exchanger 23 side or supplying tap water from the direct water supply pipe 15 to the hot water heat exchanger 23 side. Note that the switching solenoid valve 16 is normally in a switching state in which the hot water in the tank 1 is supplied to the hot water heat exchanger 23 side.

[0011] When the remote control 5 is operated to instruct heat-retention operation by the heat pump 2, the controller 4 operates the heat pump 2 and the pump 10. Then, the hot water in the tank 1 circulates through the circulation path 9 and is heated as it passes through the heat pump 2. The hot water in the tank 1 is once heated to a high temperature (e.g., 75°C) in the heat pump 2, and then the heat pump 2 is turned ON / OFF based on the temperature detected by the return temperature thermistor 11, thereby maintaining the water at a predetermined heat-retention temperature (e.g., 65°C).

[0012] On the other hand, the water heater 3 includes a water heater 20 and a bath heater 21. The water heater 20 includes a water burner 22 and a water heat exchanger 23, and the relay pipe 12 is connected to the inlet of the water heat exchanger 23. A hot water outlet pipe 26 is connected to the outlet of the water heat exchanger 23, and a hot water outlet temperature thermistor 27 for detecting the temperature of hot water and a hot water outlet flow rate sensor 17 for detecting the flow rate of hot water flowing through the hot water outlet pipe 26 are provided on the hot water outlet pipe 26. An external pipe 28 is connected to the hot water outlet pipe 26, and is provided with a plurality of hot water taps (including a shower head in the bathroom) 29, which are respectively provided in, for example, a washroom, a kitchen, a bathroom, etc. Furthermore, a mixing pipe 30 is connected between the hot water outlet pipe 26 and a point upstream of the switching solenoid valve 16 in the direct water supply pipe 15, to supply tap water into the hot water outlet pipe 26 to adjust the hot water outlet temperature. At the connection between the direct water supply pipe 15 and the mixing pipe 30, a water volume control valve 31 capable of controlling the amount of water flowing from the direct water supply pipe 15 to the mixing pipe 30 is provided.

[0013] The bath heating section 21 has a bath burner 24 and a bath heat exchanger 25. A bath return pipe 42 is connected between the inlet of the bath heat exchanger 25 and the external bathtub 41. A circulation pump 43 and a bath temperature thermistor 44 are provided in the bath return pipe 42. A bath supply pipe 45 is connected between the outlet of the bath heat exchanger 25 and the bathtub 41. The bath return pipe 42 and the bath supply pipe 45 form a reheating circulation path 46 in which hot water circulates between the bath heat exchanger 25 and the bathtub 41. A drop pipe 47 is connected between the bath return pipe 42 and the hot water outlet pipe 26. A drop solenoid valve 48 and a drop flow rate sensor 49 are provided in the drop pipe 47.

[0014] Furthermore, gas pipe 34, which supplies fuel gas to hot water burner 22 and bath burner 24, branches into hot water branch pipe 35 on the hot water heating section 20 side and bath branch pipe 36 on the bath heating section 21 side. Hot water branch pipe 35 supplies fuel gas to hot water burner 22, and bath branch pipe 36 supplies fuel gas to bath burner 24. Hot water branch pipe 35 is provided with hot water gas switching valve 37, and bath branch pipe 36 is provided with bath gas switching valve 38. In addition, a main solenoid valve 39 and a proportional control valve 40 are provided from the upstream side in gas pipe 34 before branching.

[0015] The remote control 5 is operated by the user as appropriate, and is provided with, for example, a setting button (not shown) for setting the hot water temperature, etc., and a reheating button (not shown) for commanding the reheating of hot water in the bathtub 41. The controller 4 is composed of a CPU, a storage means, a timer, etc., and is electrically connected to each thermistor, each sensor, and each valve. Based on operation commands from the remote control 5, the set temperature set by the remote control 5, information obtained from each thermistor and each sensor, etc., the controller 4 executes an operation for keeping hot water in the tank 1 warm, a hot water supply operation for supplying hot water from the hot water tap 29, and a reheating operation for reheating hot water in the bathtub 41, etc., according to a program stored in a non-transient computer-readable storage medium that is part of the storage means.

[0016] Before explaining the control of various operations by the controller 4, we will explain the actual hot water usage as disclosed in JIS2075, that is, a standard model of how 40°C hot water is used in a day in a typical household of four people, based on Fig. 2. Fig. 2 is a table showing the start time of hot water supply, the amount of hot water discharged, etc., in a typical household of four people.

[0017] JIS2075 is a regulation on the method of measuring the modal efficiency of domestic gas and oil hot water appliances, and is a method of measuring the efficiency of hot water appliances using a standard usage mode that reflects the way hot water is used in an ordinary household. Therefore, the way hot water is used disclosed in JIS2075 can be used as a standard model of how 40°C hot water is used in a day in a typical four-person household. Referring to FIG. 2, which is an example of such a standard model, the amount of hot water used when filling the bathtub 41 with hot water and when using a shower (i.e., when supplying hot water in the bathroom) is extremely large compared to when hot water is used for other purposes. Therefore, based on the amount of hot water used, it is possible to detect the time when hot water is supplied in the bathroom. Also, when filling the bathtub 41 with hot water and when using a shower, the hot water flow rate is also large compared to when hot water is used for other purposes. The only time the hot water flow rate during washing was the same as the hot water flow rate during shower use, which was at 9:59 p.m., when washing. Therefore, based on the hot water flow rate, it is possible to detect the time when hot water is supplied in the bathroom.

[0018] Therefore, the controller 4 detects the amount of hot water usage and / or flow rate over a predetermined learning period (e.g., one month) using the outlet hot water flow rate sensor 17, and stores the detection results in the storage means in association with the detection time as learning data. The controller 4 also refers to the learning data to learn the bathroom usage time period when hot water is used in the bathroom. Specifically, the controller 4 counts the times when the amount of hot water usage and / or flow rate exceeds a predetermined threshold, and determines the time period when the count exceeds a predetermined judgment value as the bathroom usage time period. For example, the controller 4 learns the time period from 19:00 to 24:00 as the bathroom usage time period.

[0019] The hot water supply operation by the controller 4 performing the above-mentioned learning will be described with reference to the flowchart shown in Fig. 3. Fig. 3 is a flowchart showing the control related to the hot water supply operation by the controller 4. When the hot water tap 29 is opened and the relay flow rate sensor 14 detects water flow (S1), the controller 4 judges whether the current time is within the learned bathroom use time zone (S2). If the current time is within the bathroom use time zone (YES in S2), the controller 4 controls the switching solenoid valve 16 to stop the supply of hot water in the tank 1 to the hot water heat exchanger 23 side and switches so that tap water is supplied directly from the water supply pipe 15 to the hot water heat exchanger 23 side (S3). The controller 4 also opens the main solenoid valve 39 and the hot water gas switching valve 37 of the gas pipe 34, and opens the proportional control valve 40 at a predetermined opening to supply fuel gas to the hot water burner 22. The controller 4 also operates the igniter to ignite the hot water burner 22. Then, tap water flows from water supply pipe 6 directly through water supply pipe 15 to relay pipe 12 and then to hot water heat exchanger 23, where it is heated by heat exchange with the exhaust gas and then flows to hot water outlet pipe 26 (S4). After that, when hot water tap 29 is closed and the hot water outlet flow rate sensor 17 detects the stop of water flow (S6), the combustion of hot water burner 22 is stopped and switching solenoid valve 16 is controlled to switch to the initial state, that is, the state in which hot water in tank 1 is supplied to hot water heat exchanger 23.

[0020] The same is true when filling the bathtub 41 with hot water. When the controller 4 detects water flow associated with a filling command from the remote control 5 or the like (S1), it determines whether the current time is within the learned bathroom use time period (S2). If the current time is within the bathroom use time period (determined as YES in S2), it controls the switching solenoid valve 16 to stop the supply of hot water in the tank 1 to the hot water heat exchanger 23 side, and switches so that tap water is supplied directly from the water supply pipe 15 to the hot water heat exchanger 23 side (S3). In addition, the master solenoid valve 39 and the hot water gas switching valve 37 of the gas pipe 34 are opened to supply fuel gas to the hot water burner 22, and the igniter is operated to ignite the hot water burner 22. Then, the tap water passes through the water supply pipe 6, the direct water supply pipe 15, the relay pipe 12, and the hot water heat exchanger 23, and flows to the hot water outlet pipe 26 after being heated by heat exchange with the combustion exhaust (S4). The controller 4 also opens the drop solenoid valve 48 of the drop pipe 47 to start dropping water into the bathtub 41. Thus, hot water heated through the hot water supply heat exchanger 23 flows from the outlet pipe 26 to the drop pipe 47, and is supplied to the bathtub 41 from the bath return pipe 42. Furthermore, when the controller 4 confirms that the flow rate detected by the drop flow rate sensor 49 has reached a preset hot water amount, it closes the drop solenoid valve 48 and stops the combustion of the hot water supply burner 22, thereby terminating the supply of hot water to the bathtub 41, i.e., the filling operation. When the controller 4 detects the stop of water flow by the outlet flow rate sensor 17 accompanying the end of the filling operation (S6), it controls the switching solenoid valve 16 to switch to the initial state, i.e., the state in which the hot water in the tank 1 is supplied to the hot water supply heat exchanger 23 side.

[0021] On the other hand, if the result of the determination after checking the flow of water in relay pipe 12 is that the current time is not the bathroom usage time zone (NO in S2), the switching state of switching solenoid valve 16 is maintained in the initial state, i.e., the state in which hot water in tank 1 is supplied to hot water heat exchanger 23, and hot water in tank 1 flows from relay pipe 12 through hot water heat exchanger 23 to hot water outlet pipe 26, and is discharged from hot water tap 29 (S5). When supplying hot water, controller 4 determines whether the temperature of hot water in circulation path 9, i.e., the temperature detected by return temperature thermistor 11, is equal to or higher than a predetermined insulation temperature. If it is confirmed that the temperature is equal to or higher than the insulation temperature, hot water burner 22 is not ignited, and hot water is not heated in hot water heat exchanger 23. However, if the temperature detected by return temperature thermistor 11 is below the insulation temperature, main solenoid valve 39 of gas pipe 34 and hot water gas switching valve 37 are opened to supply fuel gas to hot water burner 22, and an igniter is operated to ignite hot water burner 22, and hot water in tank 1 is heated by heat exchange with the exhaust gas from combustion in hot water heat exchanger 23. Therefore, the hot water heated in this way flows into hot water outlet pipe 26 and is discharged from hot water tap 29. After that, when hot water tap 29 is closed and relay flow rate sensor 14 detects the stop of water flow (S6), if hot water burner 22 is burning, the combustion of hot water burner 22 is stopped and switching solenoid valve 16 is maintained in the initial state.

[0022] In addition, whether the hot water in the tank is being used or not, if the hot water temperature detected by the outlet hot water temperature thermistor 27 is higher than the set temperature set by the remote control 5, the controller 4 controls the water volume control valve 31 to a predetermined opening to directly flow tap water from the water supply pipe 15 into the mixing pipe 30, and mixes it with the hot water in the outlet hot water pipe 26 to adjust it to the set temperature.

[0023] Next, the reheating operation will be described. After filling the bath as described above, when the reheating button on the remote control 5 is operated, the controller 4 executes the reheating operation to heat the hot water in the bathtub 41. That is, the circulation pump 43 is operated, the bath gas switching valve 38 is opened, the bath burner 24 is ignited, and the hot water in the bathtub 41 is circulated through the reheating circulation path 46 for reheating. When the temperature detected by the bath temperature thermistor 44 reaches the preset reheating temperature, the circulation pump 43 is stopped and the combustion of the bath burner 24 is stopped, and the reheating operation is terminated.

[0024] According to the hot water supply system S having the above configuration, the controller 4 detects the amount and / or flow rate of hot water used over a predetermined learning period by the hot water outlet flow rate sensor 17, associates the detection result with the detection time and stores it in the storage means as learning data, and refers to the learning data to learn the bathroom use time period when hot water is used in the bathroom. When supplying hot water during the bathroom use time period, the controller 4 controls the switching solenoid valve 16 to stop the use of hot water in the tank 1, switches to supply tap water directly from the water supply pipe 15 to the water heater 3 side, and ignites the hot water supply burner 22 to heat the tap water in the water heater 3 and then supplies it to the bathtub 41. Therefore, even if the tank 1 is made small, the hot water supply system S can be made to prevent a situation in which the amount of hot water in the tank 1 is insufficient during use of a shower, and thus prevents a situation in which the temperature of the hot water changes during use of a shower.

[0025] The hot water supply system of the present invention is not limited to the above-described embodiment, and the overall configuration of the hot water supply system as well as the configuration related to learning the bathroom usage time period can be modified as necessary.

[0026] In the above embodiment, the bathroom use time zone is learned without taking into consideration the day of the week or whether it is a holiday, but the determination of whether it is a bathroom use time zone may be associated with the date. For example, the bathroom use time zone may not be set on Saturdays, Sundays, and holidays. It is also possible to learn the bathroom use time zone separately for Saturdays, Sundays, and holidays and for weekdays.

[0027] In addition, in the above embodiment, the supply path is switched when water flow is detected, but it is also possible to configure the supply path to be automatically switched based on the time rather than the detection of water flow, i.e., when the bathroom is in use, the switching solenoid valve is automatically activated to switch to the second supply path. Furthermore, learning over a specified learning period may be done once, or may be repeated multiple times. For example, it is possible to configure the learning over a specified learning period to be repeated and the bathroom usage time period to be updated each time learning is done.

[0028] In addition, the capacity of the tank is not limited to 20 L as in the above embodiment, but may be set appropriately between 10.00 L and 25.00 L. The heat exchanger of the water heater may be provided with both a primary heat exchanger for recovering sensible heat and a secondary heat exchanger for recovering latent heat. Furthermore, although the water heater of the above-described embodiment is equipped with a bath heating section, it is also possible to adopt a water heater without a bath heating section. [Explanation of symbols]

[0029] Description of the Reference Numerals: 1··Tank, 2··Heat pump, 3··Water heater, 4··Controller (control means, learning means), 6··Water supply pipe, 12··Relay pipe (first supply path, second supply path), 15··Direct water supply pipe (second supply path), 16··Switching solenoid valve, 17··Outlet water flow sensor (flow detection means), 20··Water supply heating section, 22··Water supply burner, 23··Water supply heat exchanger, 26··Outlet water pipe (first supply path, second supply path), 29··Water supply tap (point of use), 41··Bathtub (point of use), S··Water supply system.

Claims

[Claim 1] A hot water supply system comprising: a tank for storing hot water; a heat pump for heating the hot water in the tank; a water heater for heating the supplied hot water by heat of combustion of a fuel gas; a plurality of supply paths for supplying the hot water to the points of use, including a first supply path for supplying the hot water in the tank to a predetermined point of use, and a second supply path for heating tap water in the water heater without passing through the tank and then supplying it to the point of use; and a control means for controlling the operation of the water heater and the selection of the supply paths, While the above-mentioned places of use include bathrooms, a flow rate detection means for detecting the flow rate of hot and cold water in the supply passage; and a learning means for storing the usage status of hot and cold water based on the detection result by the flow rate detection means in association with time as a usage history, and for learning the bathroom usage time period when hot water is used in the bathroom based on the usage history. A hot water supply system characterized in that, when supplying hot water to the point of use during the bathroom usage time period, the control means supplies hot water to the point of use through the second supply path without using the hot water stored in the tank.

Images