JP2007107783A - Hot water storage hot water supply system - Google Patents

Abstract

An object of the present invention is to provide a hot water storage hot water supply system that is easy to use while avoiding a decrease in the heating efficiency of a heat pump.
SOLUTION: A hot water storage tank 10 to which water of a predetermined pressure is supplied from the lower part so as to be always full, and water in the lower part of the hot water storage tank 10 is sucked and heated, and the heated hot water is returned to the upper part of the hot water storage tank 10. A heat pump 12, hot water supply means 14 and 16 for supplying hot water in the upper part of the hot water storage tank 10, a hot water storage temperature detector 34 for detecting the hot water storage temperature in the upper part of the hot water storage tank 10, and a target boiling temperature in the midnight power time zone. Midnight electric power that controls the heat pump at a predetermined high temperature and does not supply hot water in the daytime only with hot water boiled in the midnight power hours, and performs additional boiling when hot water shortage is expected In a time zone other than the time zone, the target boiling temperature is set to substantially the same temperature as the hot water storage temperature in the upper portion of the hot water storage tank 10 detected by the hot water storage temperature detector 34 to control the operation of the heat pump 12. It includes a device 18, the.
[Selection] Figure 1

Description

  The present invention relates to a hot water storage hot water supply system including a hot water storage tank and a heat pump.

  As a conventional heat pump type hot water heater (hot water storage type hot water system), the liquid for hot water supply is heated using a heat pump cycle, the heated liquid is stored from the upper part of the hot water storage tank of the hot water heater body, and heated from the lower part of the hot water storage tank. In the heat pump water heater that stops the heating operation of the heat pump body when the temperature of the liquid returned to the heat pump body that is the source and returned to the hot water storage tank or the heat pump body reaches a preset heating stop temperature, the heating stop temperature is stored in the hot water storage tank. Equipped with control means that can be varied depending on the state of the remaining hot water (stored hot water) and the outside air temperature or water temperature, while preventing hot water shortage, COP (coefficient of performance = energy obtained by boiling water in heat pump cycle ÷ heat pump cycle Boiling that does not deteriorate as much as possible) There is carried out a lower (e.g., see Patent Document 1).

JP 2004-316996 A (page 2, FIG. 1, FIG. 2)

  However, according to the above-described conventional technique, the heating stop temperature is made variable according to the remaining hot water state and the outside air temperature or the water temperature, so that an increase in the incoming water temperature to the heat pump part, which is a COP lowering factor in the heat pump cycle, is suppressed. However, when considering the efficiency in an actual heat pump cycle, it is important to make the boiling temperature as low as possible, and it has the same effect as reducing the incoming water temperature. No consideration is given to the raised temperature. For this reason, there is a problem that even if the incoming water temperature is limited, if the target boiling temperature remains high, a large efficiency improvement effect cannot be expected.

  If the target boiling temperature is generally lowered to improve the efficiency, it may interfere with the original hot water supply function that functions as the heat source of hot water in the hot water storage tank, or bacteria may propagate in the hot water in the hot water storage tank. Therefore, there is a problem that an easy-to-use hot water supply system suitable for actual use cannot be realized only by lowering the target boiling temperature.

  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 avoid the fall of the boiling efficiency of a heat pump and is easy to use.

  In order to solve the above-described problems and achieve the object, the present invention provides 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 heats by sucking water in the lower part of the hot water storage tank. A hot pump for returning heated hot water to the upper part of the hot water storage tank, hot water supply means for supplying hot water in the upper part of the hot water storage tank, a hot water temperature detector for detecting the hot water temperature in the upper part of the hot water storage tank, Set the boiling temperature to a predetermined high temperature and control the operation of the heat pump.If only hot water heated at midnight power hours is not enough to supply hot water during the day, additional boiling is expected when shortage of hot water is expected. A control device that controls the operation of the heat pump by setting the target boiling temperature to substantially the same as the hot water storage temperature at the upper part of the hot water storage tank detected by the hot water storage temperature detector in a time zone other than the midnight power time zone in which Characterized in that it obtain.

  According to the present invention, there is an effect that it is possible to obtain a hot water storage hot water supply system that is easy to use by avoiding a decrease in the boiling efficiency of the heat pump.

  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.
FIG. 1 is a diagram showing a configuration of an embodiment of a hot water storage type hot water supply system according to the present invention, FIGS. 2 to 6 are diagrams showing a hot water temperature distribution in a hot water storage tank, and FIG. 7 is a control device. It is a flowchart of the boiling-up control by.

  As shown in FIG. 1, a hot water storage hot water supply system 100 circulates a vertically long hot water storage tank 10 comprising a cylindrical body 10a, a hemispherical lower part 10b and an upper part 10c, and water and hot water storage in the hot water storage tank 10. A heat pump 12 that heats while mixing, hot water from a hot water storage tank 10 and tap water (water; city water), a mixing valve 16 that supplies hot water via a mixing pipe 15 and a hot water supply port (faucet) 14, a heat pump 12 and mixing And a control device 18 for controlling the valve 16. The mixing valve 16, the mixing pipe 15 and the hot water supply port 14 constitute hot water supply means.

  The water pipe 20 is connected to the lower part 10 b of the hot water storage tank 10 via the pressure reducing valve 22, and supplies tap water having a predetermined pressure set by the pressure reducing valve 22 into the hot water storage tank 10. The water pipe 20 and the mixing valve 16 are connected by a water supply bypass pipe 24, and tap water is supplied to the mixing valve 16. The upper part 10 c of the hot water storage tank 10 and the mixing valve 16 are connected by a hot water supply pipe 26, and hot water in the hot water storage tank 10 is supplied to the mixing valve 16.

  The lower part 10b of the hot water storage tank 10 and the suction port 12a of the heat pump 10 are connected by a low-temperature pipe 28, and water and hot water in the hot water storage tank 10 are 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 10 are connected by a high temperature pipe 30, and the high temperature hot water heated by the heat pump 12 is returned to the upper part 10c of the hot water storage tank 10.

  A temperature detector 32 and a hot water storage temperature detector 34 are installed in the cryogenic pipe 28 and the upper portion 10 c of the hot water storage tank 10, respectively, and detection signals from the temperature detector 32 and the hot water storage temperature detector 34 are output to the control device 18. Is done. The hot water storage temperature detector 34 detects the hot water storage temperature of the upper part 10 c of the hot water storage tank 10. The control device 18 includes a determination unit 18a and a storage unit 18b. Based on the hot water supply temperature and the hot water supply flow rate set by the operation unit 36 and the temperature detection values of the temperature detectors 32 and 34, the heat pump 12 and the mixing valve 16 are provided. Control the entire system. The control device 18 has a built-in clock and controls the operation of the system according to the time.

  The operation of the heat pump 12 is controlled by a command from the control device 18, and water and hot water in the hot water storage tank 10 are circulated between the heat pump 12 and the hot water storage tank 10 as indicated by an arrow A, and preset by the control device 18. Heat to the boiling temperature set.

  The mixing valve 16 is controlled by a command from the control device 18, mixes tap water supplied from the water supply bypass pipe 24 and hot water supplied from the hot water supply pipe 26, and has a built-in temperature detector and flow rate detector ( A detection signal (not shown) is fed back to the control device 18 so that the hot water supply temperature and the hot water supply flow rate are adjusted to the predetermined set values set by the operation unit 36, and the mixed hot water is supplied to the mixing pipe 15. Hot water is supplied from a hot water supply port (faucet) 14. The hot water supply temperature is generally set in a range of about 35 ° C to 60 ° C.

  The mixing valve 16 as the hot water supply means may manually adjust the mixing ratio between the tap water supplied from the water supply bypass pipe 24 and the hot water supplied from the hot water supply pipe 26. Further, if it is not necessary to adjust the hot water supply temperature, the hot water supply means may not include a mixing valve.

  Next, the overall operation of the hot water storage type hot water supply system 100 of the present embodiment will be described. First, water from the water pipe 20 is depressurized to a predetermined pressure by the pressure reducing valve 22 and supplied to the hot water storage tank 10. The hot water storage tank 10 is always filled with a predetermined pressure.

  The boiling operation of the water in the hot water storage tank 10 and hot water 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 sucked into the heat pump 12 from the lower part 10b of the hot water storage tank 10 through the low-temperature pipe 28 by the heat pump 12 that has received a boiling command from the control device 18, as indicated by an arrow A. Rarely, the heat is exchanged, heated to a set high boiling temperature (for example, 90 ° C.), and returned to the upper portion 10 c of the hot water storage tank 10 through the high temperature pipe 30. By this boiling operation, high temperature hot water at 90 ° C. is stored in a layered manner from the upper part 10c of the hot water storage tank 10 toward the lower part 10b.

  When the temperature of the hot water detected by the temperature detector 32 becomes equal to or higher than a certain temperature (for example, 60 ° C.), the boiling by the heat pump 12 is terminated by determining that all the hot water in the hot water storage tank 10 has been boiled.

  After boiling is completed, the hot water stored in the hot water storage tank 10 is used by supplying hot water from the hot water supply port 14, while gradually radiating heat over time (generally about 1 ° C per hour). However, the temperature drops.

  It is only necessary to supply hot water in the daytime with hot water in the hot water storage tank 10 boiled up in the late-night power hours, but when hot water is insufficient, the heat pump 12 is used in the daytime hours (other than the late-night power hours). It is necessary to perform additional boiling by.

  The additional boiling operation of the hot water storage type hot water supply system 100 of embodiment is demonstrated with reference to FIGS. FIG. 2 is a diagram illustrating a state of hot water in the hot water storage tank 10 immediately after the above-described boiling operation using midnight power is completed. After the boiling is completed, the 90 ° C. hot water stored in the hot water storage tank 10 is used by supplying hot water from the hot water supply port 14, and the hot water storage amount is about half of the capacity of the hot water storage tank 10 as shown in FIG. The temperature of the hot water in the hot water storage tank 10 is lowered by about 12 ° C. and about 90 ° C.-12 ° C. = 78 ° C. after about 12 hours.

  Although not shown, a plurality of temperature detectors are arranged in the vertical direction on the body portion 10a of the hot water storage tank 10, and water and hot water in the hot water storage tank 10 detected by the plurality of temperature detectors are arranged. The temperature distribution is detected and a detection signal is output to the control device 18 to determine how much hot water is stored from the temperature distribution.

  As shown in FIG. 3, the amount of hot water storage is about half the volume of the hot water storage tank 10, and the hot water boiled in the hot water storage tank 10 during midnight power hours cannot be used to supply hot water in the daytime. When a shortage of hot water is anticipated, additional heating by the heat pump 12 is performed during the daytime to increase the amount of hot water stored.

  In the state shown in FIG. 3, if the boiling is performed by the boiling control as in the prior art, the boiling is heated so that the boiling temperature becomes a high temperature of 90 ° C., which is the set temperature in the midnight power time zone. As shown in FIG. 5, the hot water in the hot water storage tank 10 is boiled so that the high temperature hot water of 90 ° C. is laminated on the hot water of about 78 ° C. originally in the hot water storage tank 10. Done. The 90 ° C. hot water and the 78 ° C. hot water are finally mixed as shown in FIG. 6, and when the 90 ° C. hot water and the 78 ° C. hot water are approximately the same amount, about 84 ° C. (90 ° C. (Average value of 78 ° C.) hot water.

  In the prior art, the heat pump 12 performs boiling with a target boiling temperature of 90 ° C. When the target boiling temperature is set to a high temperature of 90 ° C., there is no problem as the hot water supply temperature even if the target boiling temperature is set to a temperature lower than 90 ° C. (for example, the inside of the hot water storage tank 10 is finally about 84 Therefore, the COP in the heat pump cycle is lower than that in the case where 84 ° C. is set as the target boiling temperature.

  With reference to FIG. 2 to FIG. 4 and FIG. 7, boiling control of the hot water storage type hot water supply system 100 of the present embodiment will be described. In the state shown in FIG. 3, when it is predicted that only hot water in the hot water storage tank 10 cannot supply hot water in the daytime, additional heating by the heat pump 12 is performed during the daytime.

  When the boiling operation by midnight power is finished and the hot water in the hot water storage tank 10 is in a state as shown in FIG. 2, the boiling operation is stopped, and additional boiling control shown in step S0 of FIG. 7 is started. Proceed to step S1.

  In step S1, the determination unit 18a determines whether or not the current time counted by the control device 18 is outside the midnight power time period stored in the storage unit 18b, and determines that it is the midnight power time period. When it does, it progresses to step S2 and performs the boiling control in the midnight electric power time zone different from the additional boiling control of this Embodiment (it abbreviate | omits description here). If it is determined that it is outside the midnight time zone, the process proceeds to step S3.

  In step S3 and subsequent steps, since the current time is outside the midnight power time zone, the boiling control according to the present embodiment is performed. In step S3, the hot water storage temperature detector 34 detects the hot water storage temperature Ta in the upper part of the hot water storage tank 10, and the process proceeds to step S4.

  In step S4, whether or not the hot water storage temperature Ta in the hot water storage tank 10 detected in step S3 is stored in advance in the storage unit 18b of the control device 18 (the temperature is lower than the high temperature of 90 ° C.) or not. When the determination unit 18a of the control device 18 determines that Ta is less than the specified value, the process proceeds to step S5. In step S5, the specified value is set as the target boiling temperature, and the process proceeds to step S7.

  When Ta is greater than or equal to the specified value, the process proceeds to step S6. In step S6, Ta (may be set to a temperature substantially the same as Ta) is set as the target boiling temperature, and the process proceeds to step S7.

  The prescribed value is, for example, a lower limit temperature at which hot water stored in the hot water storage tank 10 does not rot or the like (for example, 60 ° C.), or a hot water supply temperature setting range of the hot water storage hot water supply system 100 of the present embodiment is For example, in the case of 35 ° C. to 65 ° C., the hot water storage tank 10 satisfies the performance if hot water of a maximum of 65 ° C. can be supplied, so that it is previously stored in the storage unit 18b according to actual use, such as 65 ° C. .

  In step S7, the heat pump 12 starts a boiling operation according to the target boiling temperature set in step S5 or step S6, and the process proceeds to step S8. In step S8, the boiling operation is performed until the hot water storage tank 10 reaches a target hot water storage amount (a target hot water storage amount in a time zone other than the midnight power time zone is set in advance; explanation is omitted in the present embodiment). To do. When the target hot water storage amount is reached, the process proceeds to step S9, and the boiling operation is stopped in step S9.

  Regarding the boiling control of the hot water storage type hot water supply system 100 described above, a specific example of boiling from the hot water storage state in the hot water storage tank 10 shown in FIG. 3 will be described. In step S3, the hot water storage temperature detector 34 detects that the upper temperature Ta in the hot water storage tank 10 is 78 ° C., and in step S4, a preset specified value (here, 60 ° C.). Since Ta is equal to or higher than the specified value of 60 ° C., the process proceeds to step S6, Ta = 78 ° C. (may be set to a temperature substantially the same as Ta) is set as the target boiling temperature, and the process proceeds to step S7. The boiling is started and the process proceeds to step S8.

  In step S8, the boiling operation is continued, and when the target hot water storage amount is reached, the process proceeds to step S9 and the boiling operation is stopped. When the boiling operation is stopped, 78 ° C. hot water is additionally heated as shown in FIG.

  In the hot water storage state shown in FIG. 4, the target hot water storage amount is ensured, hot water is avoided, the target boiling temperature is 78 ° C., and the target boiling temperature is lower than 90 ° C. in the case of the prior art. , COP reduction due to boiling by the heat pump 12 is suppressed.

  As described above, the hot water storage type hot water supply system 100 according to the present invention efficiently performs the boiling control of the heat pump 12 for the purpose of preventing hot water breakage outside the midnight power hours according to the hot water storage temperature of the hot water storage tank 10. This is useful as an energy-saving hot water storage hot water supply system that suppresses COP reduction during boiling operation.

It is a figure which shows the structure of embodiment 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 distribution in a hot water storage tank. 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 distribution in a hot water storage tank. It is a figure which shows the hot water temperature distribution in a hot water storage tank. It is a flowchart of the boiling-up control by a control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hot water storage tank 10b Lower part 10c Upper part 12 Heat pump 14 Hot-water supply port (faucet)
16 Mixing valve 18 Control device 32 Temperature detector 34 Hot water storage temperature detector

Claims (2)

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 heats the water in the lower part of the hot water storage tank and returns the heated hot water to the upper part of the hot water storage tank;
Hot water supply means for supplying hot water in the upper part of the hot water storage tank;
A hot water storage temperature detector for detecting the hot water storage temperature at the top of the hot water storage tank;
The heat pump is controlled by setting the target boiling temperature to a predetermined high temperature during the late-night power hours, and hot water heated during the late-night power hours cannot supply hot water in the daytime. The heat pump is controlled by setting the target boiling temperature to approximately the same as the hot water temperature at the top of the hot water tank detected by the hot water temperature detector during times other than the midnight power hours when additional boiling is performed. A control device,
A hot water storage hot water supply system characterized by comprising: If the target boiling temperature in a time zone other than the midnight power time zone is less than a preset specified value lower than the predetermined high temperature, the specified value is set as the target boiling temperature. The hot water storage type hot water supply system according to claim 1.

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