JP2007271119A - Reservoir type hot water supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a user-friendly reservoir type hot water supply system capable of carrying out boiling with consideration to a lost heat quantity during hot water storage. <P>SOLUTION: The reservoir type hot water supply system 100 boils hot water in a hot water reservoir 10 to a predetermined hot water storage temperature. In a controller 14, after finishing boiling of the hot water in the hot water reservoir 10 in a midnight power time zone by a heat pump 12, a hot water storage temperature Ts in the hot water reservoir 10 is detected by hot water storage temperature sensors 34a-34e, a temperature difference ΔT between the hot water storage temperature Ts and a hot water boiling temperature Tm' of the heat pump 12 detected by a boiling temperature sensor 32 is stored, and in boiling of the stored hot water in the hot water reservoir 10 in a next midnight power time zone, the hot water boiling temperature Tm' of the heat pump 12 is adjusted by using the stored temperature difference ΔT as a parameter. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hot water storage type hot water supply system that includes a hot water storage tank and a heat pump and boils hot water in the hot water storage tank in the late-night power hours.

  As a conventional hot water storage type hot water supply system, a heater (heat pump) for heating hot water, a hot water storage tank for storing water heated by the heater, and water connecting the heater and the hot water storage tank When the water flows in the pipe, the heat dissipation amount detecting means for detecting the amount of heat radiated from the water, and at least the heat dissipation amount detected by the heat dissipation amount detection means is heated by the heater and the hot water storage Control means for controlling the temperature of the water flowing into the tank, grasping the amount of heat loss in the piping as a parameter, heating the water by determining the boiling target temperature, or lack of hot water supply capacity or energy consumption There is one that obtains hot water at a predetermined temperature while preventing an increase (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2003-279137 (second page, FIGS. 1 and 2)

  In general, a hot water storage type hot water supply system performs boiling and hot water storage in the late-night power hours (usually from 23:00 to 7:00 the next morning), and the use of hot water is mainly after the end of the late-night power hours (such as daytime). Therefore, heat dissipation loss and temperature drop during hot water storage in the hot water storage tank cannot be ignored.

  However, according to the above-described conventional technology, the heat radiation loss that occurs in the pipe between the heater (heat pump) and the hot water storage tank can be reflected in the boiling temperature in the heater, but during the hot water storage in the hot water storage tank Heat dissipation loss cannot be reflected.

  Therefore, according to the above-mentioned conventional technology, when the hot water gradually boiled in the late-night power hours is at the time of actual use (usually from 7 o'clock in the morning), the hot water gradually begins to boil from the beginning. Since 8 hours to 0 hours have passed, there is a problem that the hot water storage temperature is lower than the boiling temperature and the usability is poor.

  This invention is made | formed in view of the above, Comprising: It aims at obtaining the hot water storage type hot-water supply system which can perform the boiling which considered the amount of heat loss in hot water storage.

  In order to solve the above-described problems and achieve the object, the present invention includes a hot water storage tank to which water of a predetermined pressure is supplied from the lower part so that the water is always full, and the hot water in the lower part of the hot water tank is sucked and boiled up. A heat pump for returning the heated water to the upper part of the hot water storage tank, an operation unit for setting a target boiling temperature Tm of the hot water storage tank, a suction temperature sensor for detecting the suction temperature of the heat pump, and boiling of the hot water of the heat pump A boiling temperature sensor for detecting the temperature Tm ′, a hot water storage temperature sensor for detecting the temperature Ts of the hot water in the hot water storage tank, and temperature signals from the operation unit, the suction hot water temperature sensor, the boiling temperature sensor, and the hot water temperature sensor And a control device for controlling the operation of the heat pump based on the hot water storage hot water supply system for boiling the hot water in the hot water storage tank to a predetermined hot water storage temperature. In the system, the control device detects the hot water storage temperature Ts in the hot water storage tank by the hot water storage temperature sensor after the boiling of the hot water storage in the hot water storage tank in the midnight power time zone by the heat pump, and the boiling temperature A temperature difference ΔT between the hot water boiling temperature Tm ′ of the heat pump detected by the sensor and the hot water storage temperature Ts is stored, and the hot water of the heat pump is heated when the hot water in the hot water storage tank is heated at the next midnight power time zone. The boiling temperature Tm ′ is adjusted using the stored temperature difference ΔT as a parameter.

  According to the present invention, there is an effect that an easy-to-use hot water storage hot water supply system capable of boiling up in consideration of the amount of heat lost during hot water storage can be obtained.

  Hereinafter, an embodiment of a hot water storage type hot water supply system according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing Embodiment 1 of a hot water storage hot water supply system according to the present invention, FIGS. 2 to 4 are diagrams showing hot water temperature in a hot water storage tank, and FIG. 5 is an implementation by a control device. It is a flowchart of the boiling control of the form 1 of.

  As shown in FIG. 1, a hot water storage hot water supply system 100 according to Embodiment 1 includes a vertically long hot water storage tank 10 including a cylindrical body 10a, a hemispherical lower part 10b, and an upper part 10c, and hot water in the hot water storage tank 10. And a control device 14 that controls the operation of the heat pump 12. The hot water storage tank 10 and the control device 14 are accommodated in a tank unit 18. Carbon dioxide is used as the refrigerant of the heat pump 12.

  A water supply pipe 20 is connected to the lower part 10 b of the hot water storage tank 10 to supply tap water of a predetermined pressure into the hot water storage tank 10. A hot water supply pipe 22 is connected to the upper part 10 c of the hot water storage tank 10, and hot water in the hot water storage tank 10 is supplied from the hot water supply pipe 22 to the residential piping.

  The lower part 10 b of the hot water storage tank 10 and the suction port 12 a of the heat pump 10 are connected by a low-temperature pipe 24, and hot water at the lower part of the hot water storage tank 10 is sucked into the heat pump 12. The upper part 10c of the hot water storage tank 10 and the discharge port 12b of the heat pump 12 are connected by a high temperature pipe 26, and the hot water heated by the heat pump 12 is returned to the upper part 10c of the hot water storage tank 10.

  A suction temperature sensor 30 for detecting the suction temperature of the heat pump 12 is installed in the low temperature pipe 24, and a boiling temperature sensor 32 for detecting the boiling temperature of hot water in the heat pump 12 is provided in the vicinity of the discharge port 12 b of the high temperature pipe 26. The detection signals of the suction temperature sensor 30 and the boiling temperature sensor 32 are input to the control device 14.

  Further, in the hot water storage tank 10, five hot water storage temperature sensors 34 a, 34 b, 34 c, 34 d, 34 e for detecting the hot water storage temperature at each height position in the hot water storage tank 10 are separated from each other in the height direction of the hot water storage tank 10. The detection signals of the hot water storage temperature sensors 34 a to 34 e are input to the control device 14.

  The operation of the heat pump 12 is controlled by a command from the control device 14, and the hot water in the hot water storage tank 10 is circulated between the heat pump 12 and the hot water storage tank 10 as shown by an arrow a by a circulation pump (not shown). The hot water is boiled by heat exchange with the outside air, and heated by the operation unit 16 connected to the control device 14 so as to reach a target boiling temperature preset by the user.

  The control device 14 includes a determination unit 14 a and a storage unit 14 b, and the target boiling temperature signal set by the operation unit 16 and the detected temperatures of the hot water storage temperature sensors 34 a to 34 e, the suction temperature sensor 30, and the boiling temperature sensor 32. The entire system such as the heat pump 12 is controlled based on the signal. The control unit 14 has a built-in clock and controls the operation of the entire system according to the time.

  Next, the overall operation of the hot water storage type hot water supply system 100 of the first embodiment will be described. First, water from the water supply pipe 20 is reduced to a predetermined pressure by a pressure reducing valve (not shown) and supplied to the hot water storage tank 10. The hot water storage tank 10 is always filled with a predetermined pressure.

  The boiling of the water and hot water in the hot water storage tank 10 is performed mainly in the late-night power time zone (generally, the time zone from 23:00 to 7:00 the next morning). The water and hot water in the hot water storage tank 10 are fed from the lower part 10b of the hot water storage tank 10 through the cryogenic pipe 24 by the circulation pump of the heat pump 12 that has received a boiling command from the control device 14, as shown in the arrow a. It is sucked into the inside and heat-exchanged, heated to a set boiling temperature (for example, 80 ° C .: detected by the boiling temperature sensor 32), returned to the upper portion 10c of the hot water storage tank 10 through the high temperature pipe 26. It is. By this boiling operation (operation), high temperature hot water is stored little by little from the upper part 10c of the hot water storage tank 10, and is stored in the hot water storage tank 10 over about 8 hours (23:00 to 7:00).

  At this time, in the high-temperature pipe 26 between the heat pump 12 and the tank unit 18, the temperature of the circulated hot water decreases due to heat radiation due to a temperature difference from the outside air. Although depending on the length of the high-temperature pipe 26 and the heat insulation state, when the temperature of the high-temperature pipe 26 is 5 m and the thickness of the heat insulating material is 10 mm, and the outside air temperature is 7 ° C., the temperature decreases by about 2 ° C.

  When the temperature detected by the suction temperature sensor 30 becomes equal to or higher than a predetermined temperature (for example, 70 ° C.), the boiling operation by the heat pump 12 is judged to have been heated up in the hot water storage tank 10 and finished. Hot water stored in the hot water storage tank 10 is heated and used from the hot water supply pipe 22 while being heated and after the boiling is completed, and gradually radiates heat over time (generally, about 1 hour per hour). 1 ° C) and the temperature decreases.

  Next, with reference to the target boiling temperature Tm set by the operation unit 16, the hot water storage system according to the first embodiment for mainly supplying hot water boiled in the late-night power hours to supply a desired amount of hot water. The boiling operation (operation) of the hot water supply system 100 will be described with reference to FIGS.

  FIG. 2 is a diagram schematically showing the temperature drop due to heat dissipation of each hot water layer, dividing hot water in the hot water storage tank 10 after completion of the boiling operation by midnight power into hot water storage layers every hour of the boiling operation. .

  As shown in FIG. 2, during the boiling operation, the temperature decreases by about 2 ° C. in the high-temperature pipe 26 and by about 1 ° C. per hour in the hot water storage tank 10. When the target boiling temperature Tm is set to 80 ° C., even if the control device 14 controls the operation of the heat pump 12 so that the temperature detected by the boiling temperature sensor 32 is 80 ° C., the hot water supply to the hot water storage tank 10 is performed. Since the temperature is lowered by 2 ° C. due to heat radiation accompanying the hot water, 78 ° C. hot water is supplied to the upper portion 10c of the hot water storage tank 10.

  Furthermore, when 1/8 of the total capacity of the hot water storage tank 10 per hour is stored, the temperature drops by 1 ° C. per hour, and the temperature drops from 78 ° C. to 77 ° C. in the first hour, and thereafter from 76 ° C. to 75 ° C. After 8 hours, hot water of 70 ° C. to 78 ° C. is mixed in the hot water storage tank 10. As a result, the average hot water temperature in the hot water storage tank 10 is 74 ° C. (= average temperature of 78 ° C. to 70 ° C.) even immediately after the completion of boiling, and is in the state shown in FIG.

  When boiling is performed by the above-described conventional boiling control, the hot water storage temperature (78 ° C due to high-temperature pipe heat dissipation) is detected during boiling by using a hot water temperature sensor installed at the top of the hot water tank, and the control of the control device To raise the boiling temperature by the temperature drop due to the heat radiation of the hot tube and adjust it to about 82 ° C. (80 ° C. + 2 ° C.). Therefore, the hot water temperature in the hot water storage tank rises by an average of 2 degrees to about 76 ° C.

  In this case, while the target boiling temperature set by the operation unit 16 is 80 ° C., the hot water temperature in the hot water storage tank immediately after the boiling is actually 76 ° C., the target boiling temperature is 80 ° C. The temperature is low and the amount of stored hot water is lower than the target value, so there is a high possibility of running out of hot water. In addition, the user has a suspicion of a system failure that the set hot water temperature is not reached.

  With reference to FIG.4 and FIG.5, the boiling operation control of the hot water storage type hot-water supply system 100 of Embodiment 1 is demonstrated. In the boiling operation control, the hot water storage temperature in the hot water storage tank 10 immediately after the completion of the heating shown in FIG. 3 is made to coincide with the target boiling temperature Tm set by the operation unit 16, so The temperature difference ΔT = 6 ° C. between the hot water storage temperature Ts = 74 ° C. and the target boiling temperature Tm = 80 ° C. is reflected in advance on the boiling temperature Tm ′ of the heat pump 12.

  This boiling operation control will be described with reference to the control flowchart of FIG. In step S0, the boiling operation is started, and the process proceeds to step S1. In step S1, the storage unit 14b of the control device 14 stores the boiling temperature Tm ′ of the heat pump 12 (detected by the boiling temperature sensor 32) and the hot water storage temperature sensors 34a to 34e of the hot water storage tank 10 in the previous midnight power time zone. The determination unit 14a determines whether or not the temperature difference ΔT (= Tm′−Ts) between the hot water storage temperature Ts detected in step S1 and the storage unit 14b is stored, and if it is stored, the process proceeds to step S2. If not, the process proceeds to step S3.

  In step S <b> 2, the previous temperature difference ΔT (= Tm′−Ts) is read from the storage unit 14 b of the control device 14, and the temperature difference ΔT is set to the target boiling of the hot water storage tank 10 set by the operation unit 16. In addition to the temperature Tm, this Tm + ΔT = Tm ′ is set to the heating temperature of the heat pump 12 in the current midnight power time zone, and the control device 14 performs boiling so that the detected temperature of the boiling temperature sensor 32 becomes Tm ′. The raising operation is performed, and the process proceeds to step S4.

  In step S3, since the temperature difference ΔT is not stored and the temperature drop due to heat dissipation is unknown, the target boiling temperature Tm of the hot water storage tank 10 set by the operation unit 16 by the user is set to the boiling temperature of the heat pump 12, The controller 14 performs a boiling operation so that the temperature detected by the boiling temperature sensor 32 becomes Tm, and the process proceeds to step S4.

  In step S4, it is determined by the determination unit 14a of the control device 14 whether or not the boiling end condition (for example, the hot water temperature detected by the suction hot water temperature sensor 30 is equal to or higher than Tm + ΔT-10 ° C.). When S4 is repeated and the end condition is reached, the process proceeds to step S5 to stop the boiling operation, and the process proceeds to step S6.

  In step S6, a temperature difference ΔT (= Tm′−Ts) between the boiling temperature Tm ′ of the heat pump 12 and the hot water storage temperature Ts calculated based on the detected temperatures of the hot water storage temperature sensors 34a to 34e after the completion of the boiling is obtained. And stored in the storage unit 14 b of the control device 14. Normally, the hot water storage temperature Ts is an average value of the detection temperatures of the hot water storage temperature sensors 34a to 34e, but when the detected temperature of any of the hot water storage temperature sensors 34a to 34e is lower than the target boiling temperature Tm by a certain temperature or more, The detection temperature of the hot water storage temperature sensor is excluded from the average value (to make an appropriate determination when the boiling operation is interrupted or stopped for some reason), the middle stage of the hot water storage tank 10 The hot water storage temperature sensor 34c may be regarded as a representative, and the detected temperature may be set to Ts. After step S6, the operation control is terminated.

  By the operation control by the control device 14 described above, the temperature difference ΔT between the boiling temperature Tm ′ of the heat pump 12 and the hot water storage temperature Ts after the completion of the boiling operation is corrected for each heating operation in the midnight power time zone. Then, the boiling temperature Tm ′ of the heat pump 12 is adjusted using the temperature difference ΔT as a parameter, and an optimum boiling operation can be performed in consideration of the heat radiation amount according to the season and the surrounding environment.

  In the first embodiment, as shown in FIG. 4, in the heating operation by the heat pump 12, the temperature detected by the boiling temperature sensor 32 is Tm ′ = Tm (80 ° C.) + ΔT (6 ° C.) = 86 ° C. The temperature drop in the high-temperature pipe 26 is 2 ° C., the hot water temperature supplied to the upper portion 10c of the hot water storage tank 10 is 84 ° C., and the hot water storage temperature after 8 hours is 84 ° C. to 76 ° C. (maximum from 84 ° C. in 8 hours). The temperature drops to 8 ° C. and reaches an average of 80 ° C. (84 ° C.−8 ° C. = 76 ° C.), and hot water can be stored at the target boiling temperature set by the operation unit 16.

Embodiment 2. FIG.
In the first embodiment, the hot water storage temperature Ts (temperature difference ΔT) is stored immediately after the boiling operation ends, but this is stored immediately after the end of the midnight power time period, or the boiling operation that is not related to the midnight power time period. You may make it memorize | store after the completion | finish of heating operation | movement not after immediately after completion | finish of boiling operation but after a fixed time passes.

  The form of such boiling control is demonstrated with reference to FIG. FIG. 6 is a flowchart of the boiling control according to the second embodiment by the control device 14. In FIG. 6, steps S20 to S25 are the same as steps S0 to S5 of the first embodiment shown in FIG.

  Proceeding to step S26, the determination unit 14a of the control device 14 determines whether or not the midnight power time period has ended, and if not, step S26 is repeated. When the midnight power time period ends, the process proceeds to step S27.

  In step S27, the hot water storage temperature Ts (temperature difference ΔT) calculated based on the temperature detected by the hot water storage temperature sensors 34a to 34e after the end of the midnight power period is stored in the storage unit 14b of the control device 14. Normally, the hot water storage temperature Ts is an average value of the detected temperatures of the hot water storage temperature sensors 34a to 34e, but when the detected temperature of any of the hot water storage temperature sensors 34a to 34e is lower than the target boiling temperature Tm by a certain temperature or more, The temperature detected by the hot water storage temperature sensor is excluded from the average value (to make an appropriate determination when the boiling operation is interrupted or stopped for some reason), The middle hot water storage temperature sensor 34c may be regarded as a representative, and the detected temperature may be Ts. After step S27, the operation control is terminated.

  According to the control of the second embodiment, while having the same effect as the control of the first embodiment, even when time is available from the stop of the boiling operation until the end of the midnight power time zone, It is possible to perform control that takes into account the amount of heat loss in the free time.

  As described above, the temperature difference ΔT between the boiling temperature Tm ′ of the heat pump 12 and the hot water storage temperature Ts after the completion of the boiling operation is corrected for each boiling operation in the midnight power time period, and the season and the surrounding environment An optimum boiling operation can be performed in consideration of the corresponding heat radiation amount, the target hot water storage temperature set by the user is achieved, and an easy-to-use hot water supply system is obtained.

  As described above, the hot water storage hot water supply system 100 according to the present invention is useful as a hot water storage hot water supply system that can raise hot water stored in a hot water storage tank to a boiling temperature set by a user and hardly cause hot water to run out.

It is a figure which shows Embodiment 1 of the hot water storage type hot-water supply system concerning this invention. It is a figure which shows the hot water temperature distribution in a hot water storage tank. It is a figure which shows the hot water temperature in a hot water storage tank. It is a figure which shows the hot water temperature in a hot water storage tank. It is a flowchart of the boiling control of Embodiment 1 by a control apparatus. It is a flowchart of the boiling control of Embodiment 2 by a control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hot water storage tank 10a Body part 10b Lower part 10c Upper part 18 Tank unit 12 Heat pump 12a Suction port 12b Discharge port 14 Controller 14a Judgment part 14b Memory | storage part 16 Operation part 20 Water supply pipe 22 Hot water supply pipe 24 Low temperature pipe 26 High temperature pipe 30 Suction temperature sensor 32 Boiling temperature sensor 34a, 34b, 34c, 34d, 34e Hot water storage temperature sensor 100 Hot water storage type hot water supply system

Claims (6)

A hot water storage tank to which water of a predetermined pressure is supplied from the bottom so as to be always full,
A heat pump that sucks and boils hot water at the bottom of the hot water storage tank and returns the hot water to the upper part of the hot water storage tank;
An operation unit for setting a target boiling temperature Tm of the hot water storage tank;
A suction temperature sensor for detecting a suction temperature of the heat pump;
A boiling temperature sensor for detecting a boiling temperature Tm ′ of hot water of the heat pump;
A hot water storage temperature sensor for detecting a hot water storage temperature Ts in the hot water storage tank;
A control device that controls the operation of the heat pump based on temperature signals from the operation unit, the suction temperature sensor, the boiling temperature sensor, and the hot water storage temperature sensor;
A hot water storage hot water supply system that heats the hot water in the hot water storage tank to a predetermined hot water storage temperature,
The control device detects the hot water storage temperature Ts in the hot water storage tank by the hot water storage temperature sensor after the boiling of the hot water storage in the hot water storage tank is completed by the heat pump in the midnight power time zone, and detects by the boiling temperature sensor. The temperature difference ΔT between the hot water boiling temperature Tm ′ of the heat pump and the hot water storage temperature Ts is stored. A hot water storage hot water supply system, wherein the temperature Tm ′ is adjusted using the stored temperature difference ΔT as a parameter.   2. The hot water storage system according to claim 1, wherein the boiling temperature Tm ′ of the hot water of the heat pump is set to Tm ′ = Tm + ΔT when boiling the hot water in the hot water storage tank in the next midnight power time zone. Hot water system.   The hot water storage hot water supply system according to claim 1 or 2, wherein the detection of the hot water storage temperature Ts in the hot water storage tank is performed after the end of the midnight power time period.   2. The hot water storage temperature sensor is provided in a plurality spaced apart from each other in the height direction of the hot water storage tank, and the hot water storage temperature Ts is an average value of temperature detection values of the plurality of hot water storage temperature sensors. The hot water storage type hot water supply system according to any one of 3 above.   A plurality of hot water storage temperature sensors are provided spaced apart from each other in the height direction of the hot water storage tank, and the hot water storage temperature Ts is a temperature detection value of a plurality of hot water storage temperature sensors that detect a hot water storage temperature that is equal to or higher than a predetermined temperature. The hot water storage hot water supply system according to any one of claims 1 to 3, wherein an average value is used.   A plurality of the hot water storage temperature sensors are provided apart from each other in the height direction of the hot water storage tank, and the hot water storage temperature Ts is set as a temperature detection value of any one of the plurality of hot water storage temperature sensors. The hot water storage type hot water supply system according to any one of claims 1 to 3.

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