JP2019007692A - Storage water heater - Google Patents

Abstract

To provide an energy-efficient storage water heater capable of suppressing deterioration of energy efficiency caused by freezing preventive operation.SOLUTION: A storage water heater includes: a hot water storage tank for storing hot water; a heat pump heat source machine; and a circulation heating circuit that connects the hot water storage tank and the heat pump heat source machine. The storage water heater also includes control means for predicting future hot water supply use heat quantity by learning and storing a hot water supply use situation of a user and executing hot water storage operation for storing hot water of the predicted hot water supply use heat quantity in the hot water storage tank by driving the heat pump heat source machine. The storage water heater further includes temperature detection means for detecting an inflow water temperature in the heat pump heat source machine and an outside air temperature. The control means determines whether or not freezing preventive operation is necessary on the basis of a detection temperature obtained by the temperature detection means, and when determining that the freezing preventive operation is necessary, executes the hot water storage operation by correcting the predicted hot water supply use heat quantity to increase heat quantity required for the freezing preventive operation.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hot water storage device that stores hot water heated by a heat source device such as a heat pump heat source device in a hot water storage tank and supplies the stored hot water, and more particularly to a hot water storage device that performs an operation to prevent freezing of hot water in a pipe.

  Conventionally, an external heat source device such as a heat pump heat source device and a combustion-type auxiliary heat source device have been provided, hot water heated by the external heat source device is stored in a hot water storage tank, and the stored hot water is adjusted to a hot water supply set temperature to supply hot water. Hot water storage and hot water supply devices with high possible energy efficiency are widely used. In order to further improve energy efficiency, for example, as in Patent Document 1, a technique is known in which standby power is reduced by cutting off part of the power supply during a time period when the operation is not performed.

  By the way, the hot water storage and hot water supply apparatus may be damaged if the freezing of the hot water in the piping occurs due to a decrease in the outside air temperature. In particular, the piping between the external heat source unit and the hot water storage tank, the water supply piping, the hot water supply piping, and the like are out of the case of the hot water storage hot water supply device, so that they are easily frozen even if they are covered with a heat insulating material. Therefore, when the outside air temperature or the hot water temperature in the piping falls below a predetermined temperature, it is heated by a freeze prevention heater wound around those piping, etc. The operation is performed to prevent freezing. The use of a freeze prevention heater is desired to be avoided as much as possible from the viewpoint of energy efficiency.

Japanese Patent No. 3925515

  The hot water storage system equipped with an external heat source unit performs hot water storage operation to store hot water by driving the external heat source unit based on the prediction of hot water supply usage, so hot water equivalent to the amount of heat required for hot water supply is stored in the hot water storage tank and the hot water supply ends Afterwards, no heat remains in the hot water storage tank. Therefore, even if it is configured to perform anti-freezing operation in which hot water in the hot water storage tank is circulated with the external heat source machine when there is a risk of freezing, the circulation is continued for the period until the next hot water storage operation, or It is necessary to drive the stopped external heat source machine for a short time after startup to raise the temperature.

  If the pump is continuously driven to continue the circulation, the energy efficiency of the hot water storage hot water supply device is lowered. On the other hand, when the external heat source device is driven for a short time, the hot and cold water cannot be stably heated immediately after the start-up, and if the external heat source device is repeatedly started, the energy efficiency is lowered and the external heat source device is burdened. The risk of breakage increases.

  The objective of this invention is providing the hot water storage hot-water supply apparatus with high energy efficiency which can suppress the fall of the energy efficiency by freezing prevention driving | operation.

  The hot water storage and hot water supply apparatus of the invention of claim 1 comprises a hot water storage tank for storing hot water, a heat pump heat source device, and a circulating heating circuit for connecting the hot water storage tank and the heat pump heat source device. In a hot water storage hot water supply apparatus having a control means for performing a hot water storage operation for learning and storing the situation and predicting a future hot water use heat amount and driving the heat pump heat source device to store the predicted hot water use heat amount in the hot water storage tank, Temperature detection means for detecting an incoming water temperature or an outside air temperature of the heat pump heat source unit, the control means determines whether or not the freeze prevention operation is necessary based on the stored detected temperature of the temperature detection means, and the freeze prevention When it is determined that the operation is necessary, the predicted amount of heat used for hot water supply is corrected so as to increase the amount of heat necessary for the freeze prevention operation, and the storage is performed. It is characterized by performing the operation.

  With the above configuration, when it is determined that the freeze prevention operation is necessary, the predicted amount of heat used for hot water supply can be corrected to increase the amount of heat for the freeze prevention operation, and stored during the hot water storage operation. And since the stored hot water can be used for freeze prevention operation and the duration of circulation of hot water during the freeze prevention operation can be shortened, the energy efficiency that can suppress the decrease in energy efficiency due to the freeze prevention operation Can be a hot water storage hot water supply device. Moreover, the repetition of starting of a heat pump heat source machine can be suppressed, and the durability of a heat pump heat source machine is not impaired.

  The invention of claim 2 is the temperature of the hot water storage temperature detecting means for detecting the temperature of the hot water stored in the hot water storage tank and the temperature detected by the hot water storage temperature detection means in claim 1, the temperature at which the hot water supply set temperature is difficult to discharge. In this case, there is provided an auxiliary heat source device capable of heating and discharging hot water stored in the hot water storage tank, and the hot water storage operation is completed immediately before the predicted use of hot water supply.

  With the above configuration, the stored hot water can be used for hot water supply before the temperature is lowered, so that a hot water storage hot water supply device with high energy efficiency can be realized. Also, even if the temperature of the stored hot water becomes a temperature that makes it difficult to discharge hot water at the set temperature of the hot water supply, the hot water can be heated with an auxiliary heat source machine to supply hot water. A decrease in energy efficiency can be suppressed.

  In a third aspect of the present invention, in the first or second aspect, when correction is made to increase the predicted amount of heat used for hot water supply, the hot water storage operation corresponding to the increased amount of heat used is a hot water storage operation for the predicted amount of heat used for hot water supply. It is characterized by being performed first at a lower temperature.

  With the above configuration, hot water for hot water supply is stored after storing hot water for freeze prevention operation immediately after the start of hot water storage operation so that the temperature stratification formed by hot water storage operation does not collapse. It can be set as the state where the hot water for preventive operation was stored. Also, hot water for freezing prevention operation is stored at a low temperature when stable heating is not possible immediately after the start of the heat pump heat source unit, so that the reduction in COP of the heat pump heat source unit can be suppressed and the energy efficient hot water storage hot water supply device Can be.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the hot water storage hot-water supply apparatus with high energy efficiency which can suppress the fall of the energy efficiency by freezing prevention driving | operation.

It is a figure which shows the whole structure of the hot water storage hot-water supply apparatus which concerns on the Example of this invention. It is a figure which shows an example of the setting of the target hot water storage calorie | heat amount based on the data stored by learning.

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

Initially, the whole structure of the hot water storage hot-water supply apparatus 1 is demonstrated based on FIG.
The hot water storage hot water supply device 1 includes a hot water storage tank 2, an auxiliary heat source device 3, and an external heat source device 4 including a heat pump heat source device and the like. The hot water storage hot water supply apparatus 1 stores hot water heated by the external heat source unit 4 in a hot water storage tank 2 and uses the hot water for hot water supply. Moreover, the hot water storage hot water supply apparatus 1 can use the hot water heated by the auxiliary heat source device 3 for hot water supply, bath bathing, and the like. The auxiliary heat source unit 3 is a combustion type hot water supply apparatus that heats hot water using, for example, combustion heat of fuel gas.

  A hot water discharge passage 11 for discharging hot water stored in the hot water storage tank 2 is connected to the upper part of the hot water storage tank 2. In addition, a water supply passage 12 for supplying clean water from a clean water source to the hot water storage tank 2 is connected to the lower part of the hot water storage tank 2. A bypass passage 13 branched from the water supply passage 12 is connected to the hot water passage 11, and a hot water mixing valve 14 capable of adjusting the mixing ratio as a mixing means for mixing the hot water of the hot water passage 11 and the fresh water of the bypass passage 13 to this connecting portion. Is arranged. A hot water supply passage 15 is connected to the hot water mixing valve 14, and hot water mixed by the hot water mixing valve 14 flows through the hot water supply passage 15 to supply hot water to a hot water tap or the like not shown.

  An upstream heating passage 5 a that supplies hot water to the external heat source unit 4 is connected to the lower part of the hot water storage tank 2, and a downstream heating passage 5 b that supplies hot water heated by the external heat source unit 4 to the hot water storage tank 2 is connected to the hot water storage tank 2. A circulation heating circuit 5 connected to the upper part and capable of circulating hot water between the hot water storage tank 2 and the external heat source unit 4 is formed. The upstream heating passage 5a is provided with an incoming water temperature sensor 6a (incoming water temperature detecting means) for detecting the incoming temperature of hot water entering the external heat source unit 4 from the hot water storage tank 2, a boiling pump 16 and a switching valve 17. Yes. The downstream heating passage 5b is provided with a heating temperature sensor 6b for detecting the temperature of hot water heated by the external heat source unit 4, and a return passage portion 5c branched from the downstream heating passage 5b is connected to the switching valve 17. . When heating such as immediately after starting the external heat source unit 4 cannot be sufficiently performed, the switching valve 17 can be switched so that the hot water heated by the external heat source unit 4 is sent to the external heat source unit 4 again. Although not shown, the upstream heating passage 5a and the downstream heating passage 5b are covered with a heat insulating material.

  On the outer periphery of the hot water storage tank 2, a plurality of hot water temperature sensors 2 a to 2 d (hot water temperature detection means) for detecting the temperature of the stored hot water are provided at predetermined intervals in the vertical direction. The hot water storage temperature sensors 2 a to 2 d and the hot water storage tank 2 are covered with a heat insulating material (not shown) that prevents the temperature of the hot water stored in the hot water storage tank 2 from falling. The hot water passage 11 is provided with a hot water temperature sensor 11 a for detecting the hot water temperature of hot water supplied to the hot water mixing valve 14 through the hot water passage 11. The water supply passage 12 is provided with a water supply temperature sensor 12a for detecting the temperature of the clean water supplied from the clean water source. The hot water supply passage 15 is provided with a hot water supply temperature sensor 15a for detecting the hot water supply temperature. Although not shown, the hot water supply passage 15 is wound with a freeze prevention heater.

  An auxiliary heating passage 21 for heating the hot water in the hot water storage tank 2 with the auxiliary heat source device 3 is branched from the hot water discharge passage 11 and connected to the auxiliary heat source device 3. The auxiliary heating hot water passage 22 for discharging hot water heated by the auxiliary heat source device 3 is connected to the hot water outlet passage 11 on the downstream side of the branch portion of the auxiliary heating passage 21 via the adjusting valve 23. The adjustment valve 23 adjusts the amount of hot water supplied to the hot water passage 11 through the auxiliary heating hot water passage 22. The auxiliary heating passage 21 is provided with a three-way valve 24 and a pump 25 for sending hot water to the auxiliary heat source unit 3.

  A heat exchanger passage 26 branched from the auxiliary heating hot water passage 22 is connected to the three-way valve 24. The three-way valve 24 is switched so that hot water in the hot water storage tank 2 or hot water in the heat exchanger passage 26 can be supplied to the auxiliary heat source unit 3. The heat exchanger passage 26 is provided with a heat exchanger 26a and an on-off valve 26b. The heat exchanger 26 a is used for a chasing operation in which hot water in the bathtub 29 flowing through the chasing circuit 28 is heated by heat exchange with hot water heated by the auxiliary heat source unit 3 by operation of the chasing pump 27. A heat exchanger for heating may be disposed in the heat exchanger passage 26.

  In the water supply passage 12, a check valve 12b and a branch passage portion 12c branched from the water supply passage 12 and connected to the heat exchanger passage 26 are disposed. A check valve 13 a is disposed in the bypass passage 13, and a high temperature hot water avoidance electromagnetic valve 30 a is disposed in the high temperature hot water avoidance passage 30 branched from the bypass passage 13 and connected to the hot water supply passage 15. Although illustration is omitted, the water supply passage 12 and the bypass passage 13 are wound with a freeze prevention heater.

  The hot water storage hot water supply apparatus 1 includes a control unit 7 (control means) that controls a hot water supply operation or the like based on a detection signal from the hot water temperature sensor 11a and the like, and a remote controller 7a (for a user to perform an operation of setting a hot water supply set temperature). Setting means) is communicably connected to the control unit 7.

  The external heat source unit 4 includes a heat pump circuit 36 in which a compressor 32, a condensation heat exchanger 33, an expansion valve 34, and an evaporation heat exchanger 35 are connected by a refrigerant pipe. The external heat source unit 4 compresses the refrigerant enclosed in the refrigerant pipe by the compressor 32 and raises the temperature, and heats the hot water flowing through the circulation heating circuit 5 by heat exchange with the high-temperature refrigerant by the condensation heat exchanger 33. . The refrigerant after the heat exchange expands at the expansion valve 34 and becomes cooler than the outside air, is heated by the heat exchange with the outside air at the evaporating heat exchanger 35, and is then introduced into the compressor 32 again.

  The evaporative heat exchanger 35 includes an outside air temperature sensor 35a (temperature detecting means) for detecting the outside air temperature and a blower 35b. The external heat source unit 4 includes an auxiliary control unit 37 that controls the compressor 32, the expansion valve 34, the blower 35b, and the like. The auxiliary control unit 37 is communicably connected to the control unit 7 and controls the external heat source device 4 in accordance with an instruction from the control unit 7. The outside air temperature detected by the outside air temperature sensor 35 a is transmitted to the control unit 7 via the auxiliary control unit 37.

Next, the hot water supply operation will be described.
Although not shown, the hot water supply passage 15 is provided with a hot water supply flow rate sensor and a hot water supply flow rate adjustment valve. When the hot water tap or the like is opened and the hot water flow rate sensor detects a predetermined flow rate, the control unit 7 controls the hot water so that the hot water temperature flowing through the hot water passage 15 becomes the hot water set temperature based on the hot water temperature and the hot water temperature. The mixing ratio of the mixing valve 14 is adjusted. Then, based on the hot water temperature detected by the hot water temperature sensor 15a, the controller 7 further adjusts the mixing ratio of the hot water mixing valve 14. In addition, when hot water supply at a hot water supply set temperature is difficult, such as during hot water supply, the auxiliary heat source unit 3 is operated to supply hot water.

Next, hot water storage operation will be described.
The controller 7 learns and stores time series data such as the past water temperature, the outside air temperature, and the amount of heat used for hot water supply as the hot water supply usage status. For example, as shown in FIG. 2, the control unit 7 predicts a future hot water use heat amount based on the learned and stored data, and sets a target hot water storage heat amount based on the predicted hot water use heat amount (predicted use heat amount). At this time, it is determined whether or not the freeze prevention operation is necessary based on the outside air temperature, the incoming water temperature, and the like stored up to now. It should be noted that the target hot water storage amount can be set in advance so as to increase the hot water storage amount in a time zone in which the hot water supply usage is large.

  Whether or not the freeze prevention operation is necessary is determined based on the outside air temperature up to now when the control unit 7 sets the target hot water storage amount from the predicted usage heat amount. In FIG. 2, for example, when the current time is 20:30, after the hot water storage operation to be executed this time, there is no plan for the hot water storage operation for a while (for example, 6 hours), and the current outdoor air temperature is the reference outdoor air temperature (for example, 5 ° C.). ), Or when it is predicted that the future outside air temperature will be lower than the reference outside air temperature based on the change rate of the outside air temperature up to now, it is determined that the freeze prevention operation is necessary.

  When it is determined that the freeze prevention operation is necessary, a correction is made to add to the predicted use heat amount so as to increase the amount of heat necessary for the freeze prevention operation. Then, the target hot water storage amount is set based on the corrected predicted usage heat amount. On the other hand, when it is determined that the freeze prevention operation is not necessary, the target hot water storage heat amount is set based on the predicted heat use amount. In addition, based on the incoming water temperature of the external heat source unit 4 up to now, when it is already predicted that it is lower than the reference incoming water temperature (for example, 5 ° C.) or lower than the reference incoming water temperature in the future, the freeze prevention operation is necessary. You may comprise so that it may determine.

  The controller 7 starts the hot water storage operation so that the hot water storage operation for storing the set target hot water storage amount in the hot water of the hot water storage tank 2 is completed immediately before the hot water supply is used. The hot water storage temperature in the hot water storage operation is set to, for example, a temperature of 45 ° C. or higher, at which hot water can be supplied at a normal hot water supply set temperature (eg, 42 ° C.). Basically, the lower the hot water storage temperature, the smaller the temperature difference from the incoming water temperature, so that the COP (coefficient of performance) of the external heat source unit 4 is improved. The hot water storage temperature can be changed according to the capacity of the hot water storage tank 2 and the target hot water storage amount, but the hot water storage temperature at which the COP of the external heat source unit 4 is increased is set to improve the energy efficiency of the hot water storage hot water supply device 1. .

  Since hot water for the freeze prevention operation is not supplied with hot water, the hot water storage operation is performed at a temperature lower than the hot water supply set temperature (for example, 30 ° C.). Therefore, the COP of the external heat source unit 4 can be increased, and the decrease in energy efficiency of the hot water storage hot water supply apparatus 1 due to the freeze prevention operation can be reduced. In this case, since the hot water for freezing prevention operation is lower than the hot water storage temperature for hot water supply, the hot water storage operation for hot water supply is performed after the hot water storage operation for freezing prevention operation is performed. Thereby, the temperature stratification formed in the hot water storage tank 2 does not collapse by natural convection, and does not hinder the hot water supply operation. In addition, since the external heat source unit 4 is started from a stopped state and cannot perform stable and sufficient heating, a hot water storage operation of low-temperature hot water for freeze prevention operation is performed immediately after startup, so that the COP of the external heat source unit 4 is reduced. Is suppressed. The hot water storage operation can be performed at the same hot water storage temperature as the hot water for hot water supply.

Next, the freeze prevention operation will be described.
When the control unit 7 determines that the freeze prevention operation is necessary, when the outside air temperature falls below the reference outside air temperature, when the incoming water temperature falls below the reference incoming water temperature, or when both conditions are satisfied, The freezing prevention operation in which the boiling pump 16 is driven to circulate hot water in the hot water storage tank 2 in the circulation heating circuit 5 is started. By continuing the freeze prevention operation, the hot water stored for the freeze prevention operation is agitated in the hot water storage tank 2, and hot water having a temperature higher than that of the tap water circulates. Thereby, freezing of circulation heating circuit 5 can be prevented. At this time, the external heat source unit 4 is not started, and the compressor 32 and the blower 35b are not operated. When the controller 7 detects that the incoming water temperature of the external heat source device 4 has risen by a predetermined temperature (for example, 5 ° C.) or more, it stops the freeze prevention operation. The controller 7 repeatedly executes this freeze prevention operation until the next hot water storage operation. If it is determined that the freeze prevention operation is necessary, the freeze prevention heater such as the water supply passage 12 is operated to prevent the passage of the hot water from circulating.

  The hot water stored in the upper portion of the hot water storage tank 2 is moved to the lower portion of the hot water storage tank 2 through the heat exchanger passage 26 and the branch passage portion 12c by driving the pump 25 to the circulation heating circuit 5. It is also possible to supply. Since hot water with high temperature flows through the circulation heating circuit 5, the freeze prevention operation can be stopped in a short time. In addition, since the temperature of the hot water is high, the time until the next freeze prevention operation becomes longer, so the number of executions of the freeze prevention operation can be reduced. Therefore, energy consumption due to driving of the boiling pump 16 and the pump 25 can be suppressed. In addition, it is possible to prevent freezing of the passages such as the auxiliary heating passage 21 through which hot water flows.

The operation and effect of the hot water storage hot water supply apparatus 1 of the present invention will be described.
The hot water storage hot water supply device 1 determines whether or not the freeze prevention operation is necessary based on the learned and stored data. If it is determined that the freeze prevention operation is necessary, the hot water for the freeze prevention operation is stored during the hot water storage operation. The hot water for freeze prevention operation is circulated through the circulation heating circuit 5 to prevent freezing. Since the stored hot water is used for the freeze prevention operation, the duration of the hot water circulation can be shortened during the freeze prevention operation, and the energy efficiency of the hot water storage water heater 1 can be reduced by suppressing the decrease in energy efficiency due to the freeze prevention operation. Can be high. Moreover, since the repetition of starting of the external heat source unit 4 can be suppressed, the durability of the external heat source unit 4 is not impaired, and the noise accompanying the driving of the external heat source unit 4 can be suppressed.

  Further, since the hot water storage operation is performed so as to be completed immediately before the use of the hot water supply, the stored hot water can be used for hot water supply before the temperature decreases, so that the energy efficiency of the hot water storage hot water supply apparatus 1 is improved. Since the stored hot water is heated by the auxiliary heat source unit 3 even when the hot water supply temperature becomes difficult to discharge, it is possible to use the stored hot water without waste to suppress the decrease in energy efficiency due to the use of the auxiliary heat source unit 3. it can.

  In addition, hot water storage operation for freeze prevention operation is performed during hot water storage operation for hot water supply, and the hot water storage temperature for freeze prevention operation is lower than the hot water storage temperature, so energy efficiency by freeze prevention operation Can be kept small. At this time, hot water for hot water supply is stored immediately after the start of hot water storage operation so that the temperature stratification formed by hot water storage operation does not collapse, so hot water for hot water supply is stored. It can be in the state where hot water was stored. Moreover, since the hot water storage operation for the low-temperature freeze prevention operation is performed when the stable heating immediately after the start of the external heat source device 4 cannot be performed, the decrease in the COP of the external heat source device 4 can be suppressed, and the hot water storage hot water supply device The energy efficiency of 1 can be increased.

DESCRIPTION OF SYMBOLS 1 Hot water storage hot water supply apparatus 2 Hot water storage tank 2a-2d Hot water storage temperature sensor (hot water storage temperature detection means)
3 Auxiliary heat source machine 4 External heat source machine (heat pump heat source machine)
5 Circulating heating circuit 6a Incoming water temperature sensor (incoming water temperature detection means)
7 Control unit (control means)
16 Boiling pump 25 Pump

Claims (3)

A hot water storage tank for storing hot water, a heat pump heat source device, and a circulating heating circuit connecting between the hot water storage tank and the heat pump heat source device, learning and storing the hot water use status of the user, and the amount of heat used in the future hot water supply In the hot water storage and hot water supply apparatus having a control means for performing hot water storage operation for driving the heat pump heat source device and storing the predicted hot water use heat amount in the hot water storage tank,
Comprising temperature detection means for detecting the incoming water temperature or the outside air temperature of the heat pump heat source machine,
The control means determines whether or not the freeze prevention operation is necessary based on the stored detected temperature of the temperature detection means, and when it is determined that the freeze prevention operation is necessary, the amount of heat necessary for the freeze prevention operation The hot water storage operation is performed by correcting the predicted hot water use heat quantity so as to increase the hot water storage operation. Hot water storage temperature detecting means for detecting the temperature of hot water stored in the hot water storage tank;
When the temperature detected by the hot water storage temperature detecting means is a temperature at which hot water supply set temperature is difficult to discharge, an auxiliary heat source device capable of heating and discharging hot water stored in the hot water storage tank is provided,
The hot water storage hot water supply apparatus according to claim 1, wherein the hot water storage operation is completed immediately before the predicted use of the hot water supply.   The hot water storage operation corresponding to the increased heat amount when the correction is made to increase the predicted hot water use heat amount is performed at a lower temperature than the predicted hot water storage heat operation. The hot water storage hot-water supply apparatus of 1 or 2.