JP5772883B2 - Hot water storage hot water supply system - Google Patents

Description

  The present invention relates to a hot water storage type hot water supply system.

  2. Description of the Related Art Hot water storage hot water supply systems that store hot water boiled by heating means in a hot water storage tank and take out the hot water from the hot water storage tank in response to the occurrence of a hot water supply load are widely used. In general, the hot water storage type hot water supply system has features such that the heating capability of the heating means is relatively small compared to the instantaneous hot water supply system and the like, and the rise of the capability at the time of starting the heating means is slow. For this reason, in the hot water storage type hot water supply system, it is necessary to store hot water in a hot water storage tank in advance so that hot water does not run out due to the occurrence of a hot water supply load. On the other hand, from the viewpoint of energy efficiency, it is required to utilize the heat stored in the hot water storage tank as effectively as possible.

  In addition to hot water supply by discharging hot water from the hot water tap, hot water storage type hot water supply has a function of reheating the bathtub by exchanging heat between the hot water taken out from the hot water storage tank and the bathtub water circulating from the bathtub. Systems are also known. In such a hot water storage type hot water supply system, it is also necessary to prevent the occurrence of hot water shortage (hereinafter referred to as “hot water hot water out”) with respect to the heat load required for reheating.

  As a conventional hot water storage type hot water supply system, Patent Document 1 discloses that a medium temperature additional hot water returning from the additional heat exchanger is returned to a height position of about 2/3 of the hot water storage tank, so An invention for reusing hot water) for hot water supply is disclosed.

  Further, in Patent Document 2, a connection portion for allowing additional hot water to flow into the hot water storage tank is provided at each of an intermediate portion and a lower portion of the hot water storage tank, and when the temperature of the hot water storage tank intermediate portion is equal to or lower than a predetermined value, Is returned to the middle part of the hot water tank, thereby avoiding a temperature drop in the high temperature portion at the upper part of the hot water tank and reusing the reclaimed hot water (medium temperature water) for hot water supply.

Japanese Patent Publication No.8-30605 Japanese Patent No. 3945511

  The temperature of the reclaimed hot water and the position of the temperature boundary layer between the high temperature region and the low temperature region in the hot water storage tank vary depending on the use situation. In the invention of Patent Document 1, when the temperature of the reheating hot water is low, the temperature of the upper part in the hot water storage tank is greatly reduced, so that the amount of heat storage available for reheating is greatly reduced, and the reheating hot water runs out. There is a problem that it is easy. In addition, when there is a temperature boundary layer between the high temperature region and the low temperature region in the hot water storage tank at a height of about 2/3 of the hot water storage tank, the temperature boundary layer is disturbed by the jet flow of the reheating hot water, There is also a problem that the amount of heat storage decreases due to mixing with the low temperature region.

  Further, in the invention of Patent Document 2, even if the reclaimed hot water is returned to the intermediate portion of the hot water storage tank, the reclaimed hot water often remains unused after all, and the amount of heat of the reclaimed hot water is not necessarily effectively restored. Not available.

  The present invention has been made to solve the above-mentioned problems, and provides a hot water storage hot water supply system that can save energy by effectively reusing the amount of heat of the reheating hot water with a simple configuration. The purpose is to do.

The hot water storage type hot water supply system according to the present invention is a heating means that heats water to make hot water, hot water generated by the heating means is stored from above, a hot water storage tank that stores water from below, and circulates from a bathtub. A reheating heat exchanger for exchanging heat between the bathtub water and hot water for heating the bathtub water, a reheating pump for guiding the hot water taken out from the upper part of the hot water storage tank to the reheating heat exchanger, Based on the user's instructions, an upper return channel that returns the reclaimed hot water that returns from the soaking heat exchanger to the hot water storage tank to the upper portion of the hot water storage tank, a lower return channel that returns the additional hot water to the lower portion of the hot water storage tank, and The operation mode setting means for setting the operation mode, and which of the upper return flow path and the lower return flow path should be used preferentially when returning the return hot water to the hot water storage tank in the additional operation without using the heating means Is set by the operation mode setting means. Comprising a reheating returns the hot water control means for determining on the basis of the operating mode and, the, operation mode setting means can set an automatic heat retention mode maintaining the bath temperature automatically, reheating return water control means, When the automatic heat retention mode is set, the upper return flow path has priority .

  ADVANTAGE OF THE INVENTION According to this invention, the reheating hot water which returns to a hot water storage tank from a reheating heat exchanger can be returned to the upper part of a hot water storage tank as much as possible. By returning the reclaimed hot water to the upper part of the hot water storage tank, the amount of heat of the reheated hot water can be reliably reused, and the remaining hot water remaining in the hot water tank can be prevented from remaining in the hot water storage tank. Can do. For this reason, it is possible to promote effective reuse of the amount of heat of the reclaimed hot water and to save energy. Further, when it is inconvenient to return the reclaimed hot water to the upper part of the hot water storage tank, such inconvenience can be avoided by returning the reclaimed hot water to the lower part of the hot water storage tank. Furthermore, it is only necessary to provide the return port of the reclaimed hot water at two locations, the upper and lower portions of the hot water storage tank, and it is not necessary to provide three or more return ports. It is possible to avoid complication of a mechanism for switching the flow path of the return hot water, and the above effect can be achieved with a simple configuration.

It is a block diagram which shows the hot water storage type hot-water supply system of Embodiment 1 of this invention. It is a block diagram showing the flow of the signal in the hot water storage type hot-water supply system of Embodiment 1 of this invention. It is a schematic diagram showing two tracking back circuits according to the first embodiment of the present invention. It is a schematic diagram showing the calorie | heat amount behavior at the time of reheating according to Embodiment 1 of this invention. It is a flowchart showing the control action which concerns on Embodiment 1 of this invention. It is a schematic diagram showing the additional effective heat storage amount which concerns on Embodiment 2 of this invention. It is a flowchart showing the control action which concerns on Embodiment 2 of this invention. It is a schematic diagram showing the behavior of the temperature boundary layer which concerns on Embodiment 3 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
≪Device configuration≫
FIG. 1 is a configuration diagram showing a hot water storage type hot water supply system according to Embodiment 1 of the present invention. As shown in FIG. 1, the hot water storage type hot water supply system of the present embodiment includes a hot water storage tank 1, a heating means 2, a heating pump 31, a reheating pump 32, a bathtub pump 33, a mixing means 4, a reheating heat exchanger. 5, bathtub 6, flow path switching valve 7 (flow path switching valve), heating pipe 301, water supply pipe 302, outlet pipe 303, mixing pipe 304, hot water supply pipe 305, bathtub outlet pipe 306a, bathtub return pipe 306b, a tracking return pipe 307a, a tracking upper return pipe 307b, a tracking lower return pipe 307c, a tracking return pipe 307d, the control means 100, and the like.

  The heating pipe 301 connects the lower part of the hot water storage tank 1 and the heating means 2, and connects the heating means 2 and the upper part of the hot water storage tank 1. A heating pump 31 is provided in the middle of the heating pipe 301. The heating means 2 boils water into high-temperature hot water, and is configured using, for example, a heat pump cycle. The water supply pipe 302 supplies water from a water source such as city water, and is connected to the lower part of the hot water storage tank 1. In the hot water storage tank 1, low-temperature water supplied from the water supply pipe 302 can be stored from the lower side, and hot water boiled by the heating means 2 can be stored from the upper side. The lower water and the upper hot water in the hot water storage tank 1 are maintained without being mixed with each other through the temperature boundary layer because of the specific gravity difference.

  The lead-out piping 303 connects the upper part of the hot water storage tank 1 and the mixing means 4. The mixing means 4 is further connected to a mixing pipe 304 branched from the water supply pipe 302 and a hot water supply pipe 305. The hot water supplied from the hot water storage tank 1 through the outlet pipe 303 and the water supplied from the mixing pipe 304 are mixed by the mixing means 4 to generate temperature-controlled hot water. The hot water is supplied through a hot water supply pipe 305 to a hot water supply terminal such as a bath tub 6, a faucet, or a shower.

  The reheating heat exchanger 5 heats the bathtub water by exchanging heat between the hot water supplied from the hot water storage tank 1 and the bathtub water circulating from the bathtub 6. The bathtub outlet pipe 306 a connects the reheating heat exchanger 5 and the bathtub 6. The bathtub return pipe 306 b is connected to the reheating heat exchanger 5 from the bathtub 6 via the bathtub pump 33. By these bathtub side circuits, the bathtub water is circulated from the bathtub 6 to the heat exchanger 5.

  The follow-up piping 307 a connects the upper part of the hot water storage tank 1 and the follow-up heat exchanger 5. The hot water sent from the hot water storage tank 1 through the follow-up piping 307a to the follow-up heat exchanger 5 is lowered in temperature by heat exchange and returned to the hot water storage tank 1. In the present specification, hot water (medium temperature water) returning from the reheating heat exchanger 5 to the hot water storage tank 1 is referred to as “reheating hot water”. The reclaimed hot water first flows into the reclaimed return pipe 307d. The tracking return pipe 307 d is connected to the flow path switching valve 7 from the tracking heat exchanger 5 via the tracking pump 32. An additional upper return pipe 307 b (upper return flow path) connects the flow path switching valve 7 and the upper part of the hot water storage tank 1. The chasing lower return pipe 307 c (lower return flow path) connects the flow path switching valve 7 and the lower part of the hot water storage tank 1. The flow path switching valve 7 is composed of a three-way valve that distributes the return hot water flowing from the additional return pipe 307d to the upper return pipe 307b and the additional lower return pipe 307c. It is possible to control the ratio between the flow rate of 307b and the flow rate of the additional lower return pipe 307c.

  In the illustrated configuration, the reheating upper return pipe 307 b is connected to the uppermost part of the hot water storage tank 1, but the connection position of the renewal upper return pipe 307 b to the hot water storage tank 1 is not necessarily the uppermost part of the hot water storage tank 1. There may be no position as long as the hot water stored in the upper portion of the hot water storage tank 1 is mixed with the high temperature hot water flowing into the hot water storage tank 1 from the additional hot water return pipe 307b. Further, the connection position of the reheating lower return pipe 307c with respect to the hot water storage tank 1 may not be the lowermost part of the hot water storage tank 1, and reheating hot water flowing into the hot water storage tank 1 from the reheating lower return pipe 307c is stored in the hot water storage tank. The hot water stored in the upper part of 1 is not mixed with the hot water, and the position of the hot water stored in the upper part of the hot water storage tank 1 is not lowered.

  The control unit 100 controls operations of the heating unit 2, the heating pump 31, the reheating pump 32, the bathtub pump 33, the mixing unit 4, and the flow path switching valve 7. In addition, a user interface device (not shown) such as a remote controller installed in a bathroom or kitchen is connected to the control means 100 so as to be communicable by wire or wirelessly.

  The hot water storage tank 1 is provided with six hot water storage temperature sensors 501a to 501f at intervals in the height direction. According to these hot water storage temperature sensors 501a to 501f, the hot water storage temperature in the hot water storage tank 1 can be detected together with the distribution in the height direction. The number of hot water storage temperature sensors is not limited to this, and may be any number that can detect the temperature distribution in the hot water tank 1 in the height direction.

  The heating pipe 301 is provided with a boiling temperature sensor 502 that detects the hot water temperature after heating on the downstream side of the heating means 2. The water supply pipe 302 is provided with a water supply temperature sensor 504 for detecting the water supply temperature. At the uppermost part of the hot water storage tank 1, a derived temperature sensor 503 for detecting the temperature of the hot water derived from the hot water storage tank 1 is provided. The hot water supply pipe 305 is provided with a hot water supply temperature sensor 505 that detects the temperature of hot water that flows out of the mixing means 4 and is supplied to the hot water supply terminal. The bathtub return pipe 306b is provided with a bathtub return temperature sensor 506 that detects the temperature of bathtub water flowing from the bathtub 6 into the reheating heat exchanger 5. The bathtub return temperature sensor 506 may be used as a means for detecting the temperature of bathtub water in the bathtub 6 (hereinafter referred to as “bath temperature”) by periodically operating the bathtub pump 33. Good. The hot water supply pipe 305 is provided with a hot water supply flow rate sensor 601 for detecting the amount of hot water supplied to the hot water supply terminal. The retrace return pipe 307d is provided with a retrace return hot water temperature sensor 507 (recovery return hot water temperature acquisition means) for detecting the temperature of the retrace return hot water returning from the reheating heat exchanger 5 to the hot water storage tank 1. . In addition, as the reheating hot water temperature acquisition means in the present invention, instead of directly detecting the reheating hot water temperature by the reheating hot water temperature sensor 507, the number of revolutions of the reheating pump 32, the bathtub pump 33, and the like. The value of the reheating hot water temperature may be acquired by estimation from the rotation number of the water, the detection temperature of the derivation temperature sensor 503 and the detection temperature of the bathtub return temperature sensor 506, and the like.

  FIG. 2 is a block diagram showing a signal flow in the hot water storage type hot water supply system according to Embodiment 1 of the present invention. As shown in FIG. 2, the control means 100 includes a reheating effective heat storage amount calculation means 101, a reheating required heat amount prediction means 104, a heating control means 105, a flow path switching valve control means 106, a bath target temperature setting means 107, a pump. A control unit 108, a system mode setting unit 109 as an operation mode setting unit, a tracking mode setting unit 110, and the like are included.

  The control means 100 includes a timer that is time detection means, hot water storage temperature sensors 501a to 501f, a boiling temperature sensor 502, a derivation temperature sensor 503, a feed water temperature sensor 504, a hot water supply temperature sensor 505, a bathtub return temperature sensor 506, and a return return. Information from the hot water temperature sensor 507 and the hot water supply flow rate sensor 601 is input. The control means 100 controls the heating means 2, the heating pump 31, the reheating pump 32, the bathtub pump 33, the mixing means 4, and the flow path switching valve 7 based on the input information.

  The bathtub target temperature setting means 107 sets a target temperature (hereinafter referred to as “bath target temperature”) for raising the temperature of the bathtub 6 by a chasing operation based on a user instruction input to the user interface device. To do.

  The reheating effective heat storage amount calculation unit 101 stores heat stored in the hot water in the hot water storage tank 1 based on the bath target temperature set by the bath target temperature setting unit 107 and the information detected by the hot water storage temperature sensors 501a to 501f. Of the amount, the amount of heat storage that can be used for reheating the bathtub 6 (hereinafter referred to as “reheating effective heat storage amount”) is calculated.

  The reheating required heat amount predicting means 104 is based on the past renewal use results of the user or the current temperature and / or hot water amount of the bathtub 6 or information on the reheating of the bathtub 6 (hereinafter referred to as the amount of heat necessary for reheating the bathtub 6). , Referred to as “required heat amount”).

  The heating control unit 105 includes the heating unit 2 and the heating unit 2 based on the additional effective heat storage amount calculated by the additional effective heat storage amount calculation unit 101 and the required additional heat amount predicted by the additional required heat amount prediction unit 104. The necessity for starting the pump 31 is determined.

  The flow path switching valve control means 106 (remaining return hot water control means) adjusts the number of pulses of the pulse motor that operates the flow path switching valve 7, so that the renewal upper return pipe 307 b and reheating lower return pipe 307 c Control the flow distribution of For example, as shown in FIG. 3 (A), when the opening of the flow path switching valve 7 is opened and fully opened to the upper return pipe 307b side, the entire amount of additional return hot water is stored from the upper part of the hot water storage tank 1. It flows into the tank 1. Conversely, as shown in FIG. 3B, when the opening of the flow path switching valve 7 is opened and fully opened to the lower return pipe 307 c, the total amount of the return hot water is from the lower part of the hot water storage tank 1. It flows into the hot water storage tank 1. Control of the flow path switching valve 7 is not limited to the control shown in FIG. 3, and control is performed so that a part of the refilling return hot water is returned to the upper part of the hot water storage tank 1 and the rest is returned to the lower part of the hot water storage tank 1. Also good.

  The pump control means 108 controls the rotation speed of each of the heating pump 31, the reheating pump 32, and the bathtub pump 33, and adjusts the pump circulation amount.

  The system mode setting means 109 is based on a user's instruction input to the user interface device. The system mode setting means 109 prioritizes the energy saving of the system (hereinafter referred to as “energy saving mode”), or the hot water runs out compared to this energy saving mode. An operation mode giving priority to avoiding the hot water (hereinafter referred to as “hot water avoidance mode”) is set.

  The chasing mode setting means 110 sets an operation mode related to chasing operation of the bathtub 6 based on a user instruction input to the user interface device. In the present embodiment, the chasing mode setting means 110 is an automatic warming mode that automatically maintains the bath temperature within a predetermined range, and the batch chasing that collectively raises the bath temperature that has been cooled to a mid-low temperature to the bath target temperature. In order to complete the chasing in a short time, the chasing ability (bath heating amount per unit time) is set in a form selected from the quick chasing mode in which chasing is performed with the highest priority.

≪Basic operation≫
Next, the basic operation of the hot water storage type hot water supply system of this embodiment will be described. Low temperature water flows into the lower part of the hot water storage tank 1 through the water supply pipe 302 and is stored. When the hot water storage tank 1 is boiled by the heating means 2, low-temperature water stored in the lower part of the hot water storage tank 1 is drawn into the heating pipe 301 by the heating pump 31 and guided to the heating means 2. The heating means 2 heats the led low-temperature water and boils it into high-temperature hot water. The boiled hot water flows from the upper part into the hot water storage tank 1 through the heating pipe 301 and is stored.

  When hot water is supplied to the hot water supply terminal, hot water stored in the upper part of the hot water storage tank 1 flows out from the outlet pipe 303 and is guided to the mixing means 4. At this time, the same amount of water as the extracted hot water flows from the water supply pipe 302 into the lower part of the hot water storage tank 1. The mixing means 4 mixes the water supplied from the mixing pipe 304 and the hot water supplied from the hot water storage tank 1 and supplies the mixed water to the hot water supply terminals such as the faucet, shower, and bathtub 6 through the hot water supply pipe 305.

  Further, when performing the chasing operation of the bathtub 6, the chasing pump 32 and the bathtub pump 33 are driven. Thereby, the hot water stored in the upper part of the hot water storage tank 1 is guided to the reheating heat exchanger 5 through the retreating piping 307a. At the same time, the bathtub water in the bathtub 6 is led to the reheating heat exchanger 5 through the bathtub return pipe 306b. The reclaimed hot water whose temperature is lowered by applying heat to the bathtub water in the reheating heat exchanger 5 returns to the hot water storage tank 1 through the reheating upper return pipe 307b or the reheating lower return pipe 307c. The bathtub water that has received heat at the reheating heat exchanger 5 and has risen in temperature returns to the bathtub 6 through the bathtub outlet pipe 306a. Such a chasing operation is forcibly started by a user's instruction input to the user interface device, or the bathtub temperature periodically detected by the bathtub return temperature sensor 506 is the bathtub target temperature setting means. This is automatically started when the temperature becomes lower than the predetermined target temperature set by 107 by a predetermined amount or more. Thereafter, the chasing operation is forcibly terminated by the user's instruction input to the user interface device, or the bath temperature detected by the bath return temperature sensor 506 is higher than the bath target temperature by a predetermined amount or more. When this happens, the chasing operation ends automatically.

≪Characteristic action≫
Next, a characteristic operation of the hot water storage type hot water supply system of the present embodiment will be described. First, with reference to FIG. 4, a phenomenon related to a characteristic operation will be described.

  In the hot water storage type hot water supply system of the present embodiment, it is possible to select whether to return the additional hot water to the upper part of the hot water storage tank 1 or the lower part of the hot water storage tank 1 by controlling the flow path switching valve 7. That is, by controlling the flow path switching valve 7 so as to preferentially use the reheating upper return pipe 307 b, reheating hot water can be preferentially returned to the upper portion of the hot water storage tank 1. Conversely, by controlling the flow path switching valve 7 so that the reheating lower return pipe 307 c is used with priority, the reheating hot water can be returned preferentially to the lower portion of the hot water storage tank 1. In this specification, “use preferentially the upper return pipe 307b” means that the entire amount of hot return water is added to the upper return pipe 307b or the flow rate of the upper return pipe 307b is adjusted. This means that it is larger than the flow rate of the tracking lower return pipe 307c. On the other hand, “use preferentially the lower return pipe 307c” means that the entire amount of hot return hot water is added to the lower return pipe 307c or the flow rate of the lower return pipe 307c is added. This means that the flow rate is larger than that of the upper upper return pipe 307b.

  Further, in the following description, when the reheating hot water is returned to the hot water storage tank 1, the preferential use of the reheating upper return pipe 307b is abbreviated as “returning to the upper tank” and the reheating lower return pipe 307c is referred to as “returning to the hot water tank 1”. Preferential use is abbreviated as “returning to the bottom of the tank”.

  In the present embodiment, as a reference for determining whether to return the reclaimed hot water to the upper part of the tank or to the lower part of the tank, three viewpoints of energy saving, resistance to renewed hot water shortage, and renewal ability are considered.

  Although the temperature of the reclaimed hot water varies depending on the use situation, it is usually higher than the water supply temperature, and therefore the reclaimed rejuvenated hot water has an amount of heat. When the return hot water is returned to the upper part of the tank, the amount of heat of the additional return hot water returns to the high temperature region in the upper part of the hot water storage tank 1, so that the amount of heat of the additional return hot water can be reused for hot water supply. On the other hand, when the return hot water is returned to the lower part of the tank, the hot return hot water mixes with the lower temperature region in the hot water storage tank 1 that is not used for hot water supply, so the heat amount of the additional return hot water is reused. Can not. For this reason, from the viewpoint of energy saving, it is more energy saving to return the reclaimed hot water to the upper part of the tank than to return it to the lower part of the tank. However, the condition that the temperature in the high temperature region at the upper part of the tank does not fall below the temperature effective for hot water supply is necessary.

  With regard to the resistance to running out of hot water, it is better to return the hot water to the upper part of the tank or return it to the lower part of the tank depending on whether the temperature of the hot water is higher or lower than the bath target temperature. Good is different. As shown in the left column of FIG. 4, when the flow rate circulating from the hot water storage tank 1 to the reheating heat exchanger 5 (hereinafter referred to as “tank side flow rate”) is low, or when the bath temperature is low, reheating is performed. When the performance of the heat exchanger 5 is high, the temperature of the reclaimed hot water tends to be lower than the bath target temperature. On the other hand, as shown in the right column in FIG. 4, when the tank-side flow rate is high, the bath temperature is high, or the performance of the reheating heat exchanger 5 is low, the temperature of reheating hot water is It tends to be higher than the bath tub target temperature. Note that the numerical values in FIG. 4 are all examples.

  When the temperature of the reheating water is higher than the bath target temperature, the reheating water has a heat quantity that can heat the bath water. The amount of heat effective for reheating in the high temperature region increases, and the resistance to reheating hot water becomes high. On the other hand, when the temperature of the reheating water is lower than the bath target temperature, the reheating water has a negative amount of heat with respect to the bath water. In addition, the amount of heat effective for replenishment of the high temperature region at the top of the tank is reduced. For this reason, when the temperature of the reclaimed hot water is lower than the bath target temperature, the return heat of the reclaimed hot water to the lower part of the tank increases the resistance to reheating of the reclaimed hot water.

  From the perspective of memorial ability, it is as follows. Since the temperature of the refilling hot water is surely lower than the temperature in the high temperature region at the top of the tank, the temperature in the high temperature region at the top of the tank is always lowered when the reheating water is returned to the top of the tank. The higher the temperature in the high temperature region at the top of the tank, that is, the temperature of hot water sent from the hot water storage tank 1 to the reheating heat exchanger 5, the higher the renewal capability. For this reason, regarding the reheating ability, regardless of the temperature of the reheating hot water, it is possible to maintain a high renewal ability by returning the reheating hot water to the bottom of the tank. It is possible to maintain the reheating capability to some extent by increasing the revolving speed of the reheating pump 32. However, since the revolving speed of the pump generally has an upper limit, the temperature in the high temperature region above the tank It is inevitable that the upper limit of the chasing ability will be lowered if it falls.

  Summarizing the above items, the advantages and disadvantages of whether to return the reclaimed hot water to the upper part of the tank or to the lower part of the tank are as shown in the table in FIG. That is, when the temperature of the reclaimed hot water is lower than the bath target temperature, it is advantageous in terms of energy saving to return the reclaimed hot water to the upper part of the tank. This is disadvantageous. On the other hand, when the return hot water is returned to the lower part of the tank, it is disadvantageous in terms of energy saving, but it is advantageous in terms of the resistance to the hot water shortage and the renewal ability, and has a great merit. Therefore, in the present embodiment, when the temperature of the reclaimed hot water is lower than the bath target temperature, the flow path switching valve 7 is controlled so as to return the reclaimed hot water to the lower part of the tank.

  When the temperature of the reclaimed hot water is higher than the target bath temperature, returning the reclaimed hot water to the bottom of the tank is advantageous in terms of reheating ability, but it has two points of energy saving and resistance to reheating hot water. Is disadvantageous. On the other hand, when the reclaimed hot water is returned to the upper part of the tank, it is disadvantageous in terms of renewal ability, but it is advantageous in terms of energy saving and resistance to renewed hot water shortage, and has a great merit. Therefore, in the present embodiment, when the temperature of the reclaimed hot water is higher than the bath target temperature, the flow path switching valve 7 is controlled so as to return the reclaimed hot water to the upper part of the tank.

  FIG. 5 is a flowchart of a routine representing a control operation executed by the control means 100 in the first embodiment of the present invention to realize the above function. According to the routine shown in FIG. 5, it is first determined whether or not the follow-up operation is being executed (step S1). If the follow-up operation is not executed, the flow path switching valve 7 is in the default state. (For example, the state is fully opened on the side of the bottom return return pipe 307c) (step S2). On the other hand, when the reheating operation is being executed, the bath return hot water temperature detected by the reheating hot water temperature sensor 507 and the bath target temperature set by the bath target temperature setting means 107 are next calculated. Comparison is made (step S3).

  As a result of the comparison in step S3, when the bathtub return hot water temperature is higher than the bath target temperature, the flow path switching valve 7 is controlled so as to return the additional return hot water to the upper part of the tank (step S4). In this step S4, the flow path switching valve 7 may be controlled so that the entire amount of the reclaimed hot water flows into the retreat upper return pipe 307b, or the refill return that flows into the retreat upper return pipe 307b. You may control the flow-path switching valve 7 so that the quantity of hot water may become larger than the quantity of the extra return hot water which flows into the additional lower return piping 307c.

  On the other hand, as a result of the comparison in step S3, when the bathtub return hot water temperature is equal to or lower than the bath target temperature, the flow path switching valve 7 is controlled so as to return the additional return hot water to the bottom of the tank (step S5). In this step S5, the flow path switching valve 7 may be controlled so that the entire amount of the reclaimed hot water flows into the retreat lower return pipe 307c, or the retrace return flowing into the retreat lower return pipe 307c. You may control the flow-path switching valve 7 so that the quantity of hot water may become larger than the quantity of the extra return hot water which flows into the additional upper return piping 307b.

  In the hot water storage type hot water supply system of the present invention, when the reheating hot water is returned to the upper part of the tank, the reheating hot water is mixed with the high temperature region in the upper part of the hot water storage tank 1, so Can be reused. Unlike the present invention, in the case of the configuration in which the reclaimed hot water is returned to the intermediate portion of the hot water storage tank 1, the reclaimed hot water returned to the intermediate portion of the hot water storage tank 1 may remain unused after all. In contrast, in the present invention, when the reclaimed hot water is returned to the upper part of the tank, the amount of heat of the reclaimed hot water is reliably reused, so that energy saving can be achieved. In addition, if it is inconvenient to return the reclaimed hot water to the upper part of the tank due to the state of the system and the intention of the user, the reclaimed hot water can be returned to the lower part of the tank. Can be avoided. Furthermore, in the present invention, it is only necessary to provide the return ports for the reclaimed hot water at two locations, the upper portion and the lower portion of the hot water storage tank 1, and it is not necessary to provide three or more return ports. The complexity and the complexity of the mechanism for switching the flow path of the reclaimed hot water can be avoided, and the above effect can be achieved with a simple configuration.

  Further, in the first embodiment, it is determined by the procedure shown in the flowchart of FIG. 5 whether to return the reclaimed hot water to the upper part of the tank or to the lower part of the tank, thereby saving energy, resistance to reheating hot water, and reheating. It is possible to improve the characteristics of the three points for securing the capability with a good balance. In particular, since the amount of heat effective for reheating that the high temperature region of the upper part of the tank has can be maximized, it is possible to maximize the resistance to reheating hot water.

  In step S3, the bath return hot water temperature and the bath target temperature are directly compared, but the temperature obtained by adding a predetermined value to the bath target temperature is compared with the bath return hot water temperature. If the temperature is higher than the temperature obtained by adding the predetermined value to the bath target temperature, return hot water is returned to the upper part of the tank, and if the temperature of the bath returning hot water is equal to or lower than the temperature obtained by adding the predetermined value to the bath target temperature, May be returned to the bottom of the tank. In this case, it is possible to further suppress a decrease in the tracking ability.

  Further, in the present embodiment, when the energy saving mode is set by the system mode setting means 109, the control shown in FIG. 5 is not executed and the reclaimed hot water is returned to the upper part of the tank regardless of the temperature. The flow path switching valve 7 may be controlled. Thereby, since the calorie | heat amount of reheating hot water can be collect | recovered more reliably and can be reused, according to a user's intention, energy saving can be given top priority.

  Further, in the present embodiment, when the quick chasing mode is set by the chasing mode setting means 110, the control shown in FIG. 5 is not executed, and the chasing hot water is placed at the lower part of the tank regardless of the temperature. The flow path switching valve 7 may be controlled to return. Thereby, since the temperature of the tank upper part can be maximized, according to the intention of the user, the highest priority is to maintain the tracking capability, and the tracking can be performed rapidly.

Embodiment 2. FIG.
Next, the second embodiment of the present invention will be described with reference to FIG. 6 and FIG. 7. The description will focus on the differences from the first embodiment described above, and the same or corresponding parts will be denoted by the same reference numerals. The description is omitted.

  In the second embodiment, particularly, an operation that is advantageous in realizing the energy saving effect obtained by returning the reclaimed hot water to the upper part of the tank in combination with avoidance of the renewed hot water will be described.

<< Operations Characteristic of this Embodiment >>
[Calculation of reheating effective heat storage]
First, a method of calculating the additional effective heat storage amount by the additional effective heat storage amount calculation unit 101 will be described. The right diagram in FIG. 6 shows the change in the hot water storage temperature during reheating when returning reheating hot water to the upper part of the tank. When returning the reclaimed hot water to the upper part of the tank, the intermediate reheated hot water flows into the high temperature region. While performing heat exchange, the temperature drops to the height of the region where the temperature is the same. Therefore, the temperature of the hot water storage during the chasing is generally lowered in the region higher than the temperature boundary layer while the position of the temperature boundary layer remains almost unchanged. Moreover, the hot water in the hot water storage tank 1 cannot be used for chasing unless the temperature is higher than the bath target temperature.

  Based on the above considerations, when returning additional hot water to the upper part of the tank, the additional effective heat storage amount is integrated over the region where the hot water storage temperature is equal to or higher than the reference temperature, with the bath target temperature as the reference temperature, which is the zero point of heat conversion It can be defined as the amount of heat (see the left figure in FIG. 6). Therefore, the reheating effective heat storage amount calculation means 101 integrates the heat amount in the region where the hot water storage temperature is equal to or higher than the bathtub target temperature based on the temperature distribution detected by the hot water storage temperature sensors 501a to 501f, and tracks the integrated value. Calculated as effective heat storage.

[Prediction of additional heat required]
Next, an operation for predicting the amount of heat required for reheating by the reheating required heat amount prediction unit 104 will be described. The amount of heat required for reheating is the amount of heat necessary to raise the temperature of the bathtub 6 from the current temperature to the bathtub target temperature. Therefore, the amount of hot water in the bathtub 6 (for example, 200 L), the temperature difference between the bath target temperature (for example, 40 ° C.) and the current bath temperature (for example, 30 ° C.), the density of water (for example, 1 kg / L), and the specific heat of water (For example, 1 kcal / g ° C.). In this calculation, as the amount of hot water in the bathtub 6, a predetermined value (for example, 200 L) may be used, or a value set by the user using the user interface device may be used. Alternatively, the total amount of water injected into the bathtub 6 obtained by integrating the flow rates detected by the hot water supply flow sensor 601 may be used as the amount of hot water in the bathtub 6. Further, for example, a water level detection means such as a pressure sensor is provided in the bathtub return pipe 306b, and an initial learning is made between the integrated flow rate of the hot water supply flow rate sensor 601 and the bathtub water level. You may make it ask.

  In addition, in the case of a system that learns and stores the amount of heat required for the past renewal, the value of the learning result that is predicted on the day in the form of the maximum value or average value within a predetermined period in the past is predicted for the amount of heat required for renewal. It may be a value. In this case, the learning of the amount of heat required for reheating may be learned from the amount of hot water in the bathtub 6 and the difference between the bath temperatures at the start and end of the reheating operation, or the bathtub return pipe 306b or The flow rate circulating through the bathtub outlet pipe 306a is detected based on the flow rate sensor (not shown) or the rotation speed of the bathtub pump 33, and the temperature difference between the inlet and outlet of the bathtub water of the reheating heat exchanger 5 is detected by the temperature sensor. You may learn by doing.

  In the first embodiment described above, when the temperature of the reheating hot water is lower than the bath target temperature, the reheating hot water is returned to the lower part of the tank in order to increase the resistance to reheating hot water. However, even when the temperature of the reheating hot water is lower than the bath target temperature, it can be predicted that there is no possibility that the reheating hot water runs out if the reheating effective heat storage amount is larger than the reheating required heat amount. Therefore, in this embodiment, even if the temperature of the reclaimed hot water is lower than the bath target temperature, if the effective heat storage amount is larger than the required heat amount, the reclaimed return hot water is returned to the upper part of the tank. Then, it was decided to recover the calorie of the reclaimed hot water.

  FIG. 7 is a flowchart of a routine representing a control operation executed by the control means 100 in the second embodiment of the present invention to realize the above function. According to the routine shown in FIG. 7, steps S1 to S4 are performed in the same manner as the routine shown in FIG. When the bath return hot water temperature is equal to or lower than the bath target temperature in step S3, the reheating effective heat storage amount calculated by the reheating effective heat storage amount calculation unit 101 and the reheating required heat amount prediction unit 104 are predicted next. The reheating required heat amount is compared (step S6). As a result of the comparison in step S6, when the additional effective heat storage amount is larger than the additional required heat amount, the flow path switching valve 7 is controlled to return the additional return hot water to the upper part of the tank (step S7). On the other hand, when the reheating effective heat storage amount is equal to or less than the reheating necessary heat amount, the flow path switching valve 7 is controlled so as to return the reheating hot water to the lower part of the tank (step S8).

  According to the control of this embodiment described above, it is possible to increase the chances of recovering the amount of heat of the reclaimed hot water while reliably avoiding the renewed hot water shortage, and thus further energy saving can be achieved. In particular, in this embodiment, when calculating the additional effective heat storage amount, the bath target temperature is set as a reference temperature that is a zero point in terms of heat amount, and the additional effective heat storage amount is based on a region where the hot water storage temperature is equal to or higher than the reference temperature. Is calculated. As a result, the reheating effective heat storage amount can be calculated more accurately, so that avoiding reheating hot water can be achieved with higher accuracy.

  In step S6, the additional effective heat storage amount and the additional required heat amount are directly compared. However, a value obtained by adding a predetermined value as a margin to the additional required heat amount and the additional effective heat storage amount are obtained. In comparison, when the additional effective heat storage amount is larger than the value obtained by adding the predetermined value to the additional heat amount, the additional return hot water is returned to the upper part of the tank, and the additional effective heat storage amount is set to the additional required heat amount. When the value is equal to or less than the added value, the reclaimed hot water may be returned to the lower part of the tank. In addition, when the heating means 2 is operated during boiling operation to perform boiling, the amount of heat that can be increased by the heating means 2 during the tracking operation may be included in the additional effective heat storage amount. Further, the amount of heat required for additional heating may be predicted as the required amount of heat for one current additional operation, or may be predicted as a total including the additional amount of required heat that may still occur on the day.

  In addition, when calculating the additional effective heat storage amount, the additional effective heat storage amount is calculated from the area excluding the amount of heat stored in the hot water storage tank 1 that is predicted to be required for hot water supply to a faucet or shower. You may make it calculate. In this case, the amount of heat predicted to be required for hot water supply may be predicted based on past hot water supply usage results of users or predetermined design values. When predicting based on the past hot water usage history of the user, for example, based on information from the timer, the hot water temperature sensor 505, and the hot water flow rate sensor 601, the hot water load performance for each time zone is stored every day. Based on the stored hot water supply load results, it is possible to use a method of predicting the hot water supply load on the day and predicting the necessary heat storage amount for hot water supply so that hot water does not run out with respect to the predicted hot water supply load. Further, when predicting based on a predetermined design value, for example, in a time zone in which a large amount of hot water is generally predicted (for example, from 6:00 pm to 11:00 pm), the necessary heat storage amount for hot water supply is set to a large value (for example, It is possible to use a method of setting the required heat storage amount for hot water supply to be small (for example, 80 L converted to 42 ° C.).

  When the automatic heat retention mode is set by the reheating mode setting means 110, the reheating hot water is returned to the upper part of the tank without comparing the reheating effective heat storage amount and the requisite heating amount. The flow path switching valve 7 may be controlled. This is because when the automatic heat retention mode is set, the amount of heat necessary for one reheating operation is small, and therefore, the possibility of occurrence of reheating hot water is small. According to such control, it is possible to realize the energy saving and avoidance of running-off hot water with a simple method.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described with reference to FIG. 8. The description will focus on the differences from the above-described embodiment, and the same or corresponding parts will be described with the same reference numerals. Omitted.

  In the present third embodiment, a method for avoiding the problem that the amount of effective reheating heat remarkably decreases particularly when reflowing hot water having a high flow rate is returned to the upper part of the tank will be described.

<< Operations Characteristic of this Embodiment >>
First, the phenomenon according to the present embodiment will be described with reference to FIG. In the case where the return hot water is returned to the upper part of the tank, when the flow rate of the hot return hot water ejected into the hot water storage tank 1 is small and the momentum does not reach the temperature boundary layer, the temperature distribution during the follow-up operation is The position of the temperature boundary layer is hardly changed, and the temperature at a position higher than the temperature boundary layer is uniformly reduced as a whole (see the upper part of FIG. 8).

  On the other hand, in the case where the flow rate at which the reclaimed hot water spouts into the hot water storage tank 1 is large and the momentum reaches the temperature boundary layer, the high temperature region above the temperature boundary layer and the The low temperature region is mixed, the position of the temperature boundary layer is lowered, the temperature on the upper side of the temperature boundary layer is greatly lowered, and the reheating effective heat storage amount is remarkably reduced (see the lower part of FIG. 8). In order to avoid this situation, in the present embodiment, switching between returning the return hot water to the upper part of the tank or returning to the lower part of the tank is performed depending on whether or not the momentum of the return hot water reaches the temperature boundary layer.

  Specifically, first, a range (hereinafter referred to as “influence range”) within which the momentum of the chasing return hot water sprayed into the hot water storage tank 1 from the chasing upper return pipe 307b reaches is previously grasped by experiments and calculations. . The lower limit position of the influence range is hereinafter referred to as “predetermined position”. During the chasing operation, the position of the temperature boundary layer is determined based on the temperature distribution detected by the hot water storage temperature sensors 501a to 501f. In this case, for example, the position having the steepest temperature gradient may be determined as the position of the temperature boundary layer. And when the position of the temperature boundary layer is lower than the predetermined position, the flow path switching valve 7 is controlled so as to return the reclaimed hot water to the upper part of the tank, and the position of the temperature boundary layer is higher than the predetermined position. Controls the flow path switching valve 7 so that the return hot water is returned to the lower part of the tank. In this embodiment, by performing such control, it is ensured that the high temperature region on the upper side of the temperature boundary layer and the low temperature region on the lower side are mixed by the reheating hot water, and the reheating effective heat storage amount is remarkably reduced. Can be avoided.

  Further, in the present embodiment, the relationship between the jetting flow rate of the refilling return hot water ejected into the hot water storage tank 1 from the retreat upper return pipe 307b and the influence range is grasped in advance by experiments and calculations, and during the reheating operation, From the number of rotations of the reheating pump 32 and the diameter of the recirculation return port to which the recirculation upper return pipe 307b is connected, the flow velocity at which the recirculation return hot water spouts into the hot water storage tank 1 is calculated. The influence range may be calculated based on the ejection flow velocity, and the above control may be performed with the lower limit of the calculated influence range as a predetermined position. In this case, since the influence range can be set according to the jetting flow rate of the refilling hot water that changes depending on the rotation speed of the reheating pump 32, the high temperature region on the upper side of the temperature boundary layer and the low temperature region on the lower side thereof. And can be more reliably prevented from being mixed with the reheating hot water.

  Further, in the present embodiment, when the position of the temperature boundary layer detected based on the outputs of the hot water storage temperature sensors 501a to 501f is higher than the predetermined position, the rotational speed of the reheating pump 32 is corrected in the decreasing direction. You may do it. As a result, the jet flow rate of the reclaimed hot water is reduced and the above-mentioned range of influence is reduced, so that the reheated hot water can be placed in the upper part of the tank without mixing the upper high temperature region and the lower low temperature region of the temperature boundary layer. It becomes possible to return. For this reason, the opportunity to collect | recover the calorie | heat amount of reheating hot water increases, and energy saving can be aimed at.

  Furthermore, in this embodiment, when the position of the temperature boundary layer detected based on the outputs of the hot water storage temperature sensors 501a to 501f is higher than the predetermined position, the rotational speed of the reheating pump 32 is corrected in the decreasing direction. Instead of this, the flow rate of the flow switching valve 7 may be corrected in a direction in which the flow rate of the tracking upper return pipe 307b is decreased and the flow rate of the tracking lower return pipe 307c is increased. As a result, the jet flow rate of the reclaimed hot water from the reheated upper return pipe 307b is reduced and the above-mentioned influence range is reduced, so that the high temperature region on the upper side of the temperature boundary layer and the low temperature region on the lower side are mixed. While avoiding it, it becomes possible to recover the amount of heat of the reclaimed hot water, thereby saving energy.

DESCRIPTION OF SYMBOLS 1 Hot water storage tank, 2 Heating means, 4 Mixing means, 5 Heating heat exchanger, 7 Flow path switching valve, 31 Heating pump, 32 Heating pump, 33 Bath pump, 100 Control means, 301 Heating piping, 302 Water supply piping, 303 Leading piping, 304 Mixing piping, 305 Hot water piping, 306a Bathing piping, 306b Bathing piping, 307a Tracking piping, 307b Tracking top return piping, 307c Tracking bottom return piping, 307d Reheating pipe, 501a to 501f Hot water storage temperature sensor, 502 Boiling temperature sensor, 503 Derived temperature sensor, 504 Feed water temperature sensor, 505 Hot water temperature sensor, 506 Bath return temperature sensor, 507 Reheating water temperature sensor, 601 Hot water supply Flow sensor

Claims (5)

Heating means for heating the water to hot water;
A hot water storage tank for storing hot water generated by the heating means from the upper side and storing water from the lower side,
A reheating heat exchanger for exchanging heat between the bathtub water circulating from the bathtub and hot water for heating the bathtub water;
A reheating pump for guiding hot water taken out from the upper part of the hot water storage tank to the reheating heat exchanger;
An upper return flow path for returning the reclaimed hot water returning from the reheating heat exchanger to the hot water storage tank to the upper portion of the hot water storage tank;
A lower return flow path for returning the reheating hot water to the lower part of the hot water storage tank;
An operation mode setting means for setting an operation mode based on a user's instruction;
In the reheating operation that does not use the heating means, when returning the reheating hot water to the hot water storage tank, which of the upper return flow path and the lower return flow path has priority is used. Reheating hot water control means determined based on the operation mode set by
Equipped with a,
The operation mode setting means can set an automatic heat retention mode for automatically maintaining the bath temperature,
The reheating hot water control means gives priority to the upper return flow path when the automatic heat retention mode is set . In the hot water storage tank, the return port of the reheating hot water is provided only in two places, the return port of the upper return channel and the return port of the lower return channel,
The return port of the upper return channel is at a position where the reheating hot water is mixed with hot water stored in the upper part of the hot water storage tank,
2. The hot water storage hot water supply system according to claim 1, wherein the return port of the lower return flow path is located at a position where the reheating hot water does not mix with hot water stored in an upper portion of the hot water storage tank.   The hot water storage hot water supply system according to claim 2, wherein a return port of the upper return flow path is at an uppermost part of the hot water storage tank. The operation mode setting means is capable of setting an operation mode giving priority to the tracking ability,
The hot water supply type hot water supply system according to any one of claims 1 to 3, wherein the reheating hot water control means prioritizes the lower return flow path when an operation mode in which the reheating capacity is prioritized is set. system. The operation mode setting means can set an operation mode giving priority to energy saving,
The hot water storage type hot water supply system according to any one of claims 1 to 3, wherein the additional return hot water control means prioritizes the upper return flow path when an operation mode prioritizing the energy saving is set.

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