JP2008175426A - Heat pump-type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump-type water heater capable of surely completing heating-up during a late-night time zone even when a large amount of water of intermediate temperature is stored in a hot water storage tank before starting a heating-up operation. <P>SOLUTION: In this heat pump-type water heater comprising a plurality of stored hot water temperature detecting means 7a-7h vertically disposed on a side face of the hot water storage tank 1 and detecting a temperature of hot water in the hot water storage tank 1, a heat pump-type heating means 2 for heating the hot water in the hot water storage tank 1, and a control means 18 calculating a necessary heating-up time on the basis of the heating-up amount and a heating capacity of the heat pump-type heating means 2, the control means 18 judges the amount of water of intermediate temperature in the hot water storage tank 1 on the basis of the hot water temperatures detected by the stored hot water temperature detecting means 7a-7h, selects a correction coefficient for heating according to the amount of water of intermediate temperature, corrects the heating capacity of the heat pump-type heating means 2 by the selected correction coefficient for heating, and calculates the necessary heating-up time, thus the boiling-up can be surely completed during the late-night time zone even when a large amount of water of intermediate temperature is stored. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat pump type water heater that heats hot water in a hot water storage tank by means of a heat pump type heating means, and particularly relates to control of a boiling operation of the heat pump type heating means.

Conventionally, in this type of power, the unit price of the contracted power by time zone is cheap at night, for example, from 23:00 on the day to 7:00 on the next day, the heat pump heating means is operated to boil most of the hot water in the hot water storage tank, The heated hot water is used as a heat source for heating and baths, and is used for hot water supply. In addition, in the case of using such late-night power, the required boiling time H is previously set to the boiling amount Q, the heat pump type so that the boiling is completed shortly before the end of the late-night power period (7:00 on the next day). It is calculated by the following equation from the heating capacity W of the heating means and the heating correction coefficient α.
H = Q / (860 × W × α)
A so-called peak shift is performed to control the boiling start time. (For example, refer to Patent Document 1.)
JP 2004-218873 A

  By the way, in this conventional heat pump type hot water heater, hot water stored in the hot water storage tank is taken out and used as a heat source for heating or bathing, and the intermediate hot water whose temperature is lowered by heat exchange is returned to the hot water storage tank. As a result, medium-temperature water having a temperature drop of about 40 ° C. to 60 ° C. is stored in the hot water storage tank. If a large amount of medium-temperature water is stored in the hot water storage tank and the boiling operation is started, the heating capacity of the heat pump heating means with respect to the medium-temperature water is greatly reduced. The problem was that the time was long and the boiling in the midnight hours was not finished.

  In order to solve the above-mentioned problems, the present invention is particularly configured in claim 1 to detect the temperature of hot water in a hot water storage tank in which hot water is stored inside and a plurality of hot water tanks provided in the upper and lower sides of the hot water tank. A heat pump type comprising a hot water storage temperature detection means, a heat pump type heating means for heating hot water in the hot water storage tank, and a control means for calculating a required boiling time based on the amount of boiling and the heating capacity of the heat pump type heating means. In the water heater, the control means determines the amount of intermediate temperature water in the hot water storage tank from the hot water temperature detected by the hot water storage temperature detection means, and selects a heating correction coefficient corresponding to the amount of intermediate temperature water and is selected. The required boiling time is calculated by correcting the heating capability of the heat pump heating means by a heating correction coefficient.

  According to a second aspect of the present invention, the control means selects the smaller heating correction coefficient as the amount of medium-temperature water increases.

  According to a third aspect of the present invention, the control means calculates the amount of medium hot water from the number of the hot water storage temperature detection means that detects the first predetermined temperature or higher and the second predetermined temperature or lower.

  According to claim 1 of the present invention, by selecting a heating correction coefficient according to the amount of medium-temperature water, it is possible to calculate the required boiling time in consideration of a decrease in the heating capability of the heat pump heating means with respect to the medium-temperature water. Boiling can be completed in the midnight hours when the unit price of electricity is low.

  Further, according to claim 2, by selecting a smaller heating correction coefficient as the amount of medium warm water increases, when the amount of medium warm water is large, a longer required boiling time is taken and the boiling start time is advanced. Boiling can be completed in the midnight hours when the power unit price is cheap.

  According to the third aspect of the present invention, the control means can easily determine the amount of medium hot water from the number of hot water storage temperature detection means that have detected a predetermined temperature range.

Next, a heat pump type water heater according to an embodiment of the present invention will be described with reference to FIG.
1 is a hot water storage tank having a capacity of 370 L for storing hot water, 2 is a heat pump heating means for heating the hot water in the hot water storage tank 1, 3 is a hot water tap, 4 is a hot water heating terminal such as a bath room temperature water heating dryer or a floor heating terminal It is a vessel.

  A heat pump circulation circuit 5 connects the hot water storage tank 1 and the heat pump type heating means 2 so as to be circulated. A heat pump circulation pump 6 is provided in the heat pump circulation circuit 5 and circulates the hot water in the hot water storage tank 1. The heat-pump circulation circuit 5 is composed of a heat-pump forward pipe 5a connected to the lower part of the hot water storage tank 1 and a heat-pong return pipe 5b connected to the upper part of the hot water storage tank 1. Heated by the heat pump heating means 2, the heated hot water is returned to the upper portion of the hot water storage tank 1 from the heat pump return pipe 5b, and the hot water is sequentially stacked from the upper portion to store the hot water.

  In addition, the hot water storage temperature detection for detecting the temperature of hot water at the position where the hot water storage amount is 20L, 50L, 100L, 150L, 200L, 250L, 300L, 350L measured from the top in the vertical direction of the side surface of the hot water storage tank 1 Hot water storage temperature sensors 7a to 7h are provided as means. The temperature information detected by the hot water storage temperature sensor 7h is for detecting the heating stop temperature when the boiling operation is performed. When the hot water storage temperature sensor 7h reaches the heating stop temperature, the boiling operation is terminated. It is.

  8 is a water supply pipe connected to the lower end of the hot water storage tank 1 to supply water into the hot water storage tank 1, 9 is connected to the upper end of the hot water storage tank 1, a hot water discharge pipe for discharging hot hot water, and 10 is branched from the water supply pipe 8. The water supply bypass pipe 11 is a mixing valve that mixes water from the water supply bypass pipe 10 and hot water from the hot water discharge pipe 9 at a set temperature, and 12 is a hot water supply pipe that supplies hot water having the mixed set temperature. 13 is a hot water supply temperature sensor provided downstream of the mixing valve 11, 14 is a hot water supply flow rate sensor for counting the amount of hot water supply, 15 is a pressure reducing valve for reducing the water pressure to a predetermined pressure, and 16 is provided in the middle of the water supply pipe 8. A water supply temperature sensor for detecting the temperature, 17 is a pressure relief valve for releasing the overpressure caused by heating, 18 is input by various sensors such as operation start / stop control of the heat pump type heating means 2 and a hot water storage temperature sensor. Control means having a microcomputer for controlling the drive of the actuator.

  Next, 19 is a heating heat exchanger for heating the heat medium of the hot water heating terminal 4, and its primary side is connected to the heat transfer pipe 20 connected to the upper part of the hot water tank 1 and the lower part of the hot water tank 1. The high-temperature hot water taken out from the hot water storage tank 1 is formed by the operation of the primary-side circulation pump 23 provided in the middle of the heat exchange return pipe 21. It is circulated through the heating heat exchanger 19 and the medium-temperature water whose temperature has decreased due to the heat exchange is returned to the hot water storage tank 1 again.

  The secondary side of the heating heat exchanger 19 is connected to a secondary side heating circulation circuit 26 composed of a heating forward pipe 24 and a heating return pipe 25 so that the circulating heat medium of the hot water heating terminal 4 can be circulated. The expansion tank 27 provided in the middle of the heating return pipe 25 absorbs the pressure increase due to the volume expansion of the circulating heat medium, and the operation of the secondary side circulation pump 28 also provided in the middle of the heating return pipe 25 activates the hot water heating terminal 4. The circulating heat medium is circulated to the heating heat exchanger 19 and heated by the hot water on the primary side to be heated or dried. 29 is the start / stop of the operation of the secondary side heating circulation circuit 26. Heating operation instruction means for instructing.

  When the heating operation instruction means 29 instructs the start of the heating operation, the primary side circulation pump 23 and the secondary side circulation pump 28 are started to drive, and the hot water in the hot water storage tank 1 is heated to the heating heat exchanger. 19 is heated to heat the circulating heat medium in the secondary side heating circulation circuit 26, and the heated circulating heat medium radiates heat in the hot water heating terminal 4 to perform heating. At this time, the rotational speed of the primary side circulation pump 23 and / or the secondary side circulation pump 28 is appropriately set so that the temperature detected by a temperature sensor (not shown) provided in the secondary side heating circulation circuit 26 becomes a predetermined temperature. Adjusted. Further, the medium-temperature water whose temperature has decreased due to heat exchange with the secondary side is returned to the lower part of the hot water storage tank 1. Then, when there is an instruction to stop heating, the driving of the primary side circulation pump 23 and the secondary side circulation pump 28 is stopped to end the heating operation.

Next, the operation of the embodiment shown in FIG. 1 will be described with reference to the diagram showing the temperature form of the hot water temperature in the hot water storage tank 1 in FIG. 2 and the flowcharts shown in FIGS.
FIG. 2 is an example showing the temperature form of the hot water temperature in the hot water storage tank 1 before starting the boiling operation after using the hot water stored in the hot water storage tank 1 for heating operation or hot water supply. amount of hot water storage layer of the a temperature T _H is 60 ° C. or higher, amount of hot water storage layer temperature T _M is 40 ° C. or more and less than 60 ° C. in B, the layers of the hot water storage amount C is assumed temperature T _L is less than 40 ° C. .

First, when the unit price of the contracted power by time zone reaches an inexpensive midnight time zone (for example, 23:00), the control means 18 starts boiling control, and the past several days in step 1 (hereinafter abbreviated as S1). Within a predetermined temperature range (for example, a range of 65 ° C. to 90 ° C.) from the heat consumption amount estimated to be used the next day from the maximum value of the heat consumption amount of the minute and the feed water temperature detected by the feed water temperature sensor 16 any water heating target temperature _{T O} of, for example, set the 90 ° C., the feed water temperature _{T W} from a water supply temperature sensor 16 in S2, for example, reads the 7 ° C.. Subsequently, the read remaining hot water L _t of the hot water storage tank 1 from the detected temperature of the hot water storage temperature sensor 7a~7h at S3, the amount of hot water in the present embodiment the remaining hot water has a temperature of 2 to be determined that T _H ( in hot water storage amount a of ° C.), read hot water storage amount to a position where the hot water storage temperature sensor 7c are disposed out of the hot water storage amount a, that the 100L as remaining hot water L _t. Then, S4 by the number z of detecting the 40 ° C. or higher and 60 ° C. or less is judged that out in hot water of the hot water temperature sensor 7a to 7h, where hot water storage temperature sensor 7d~ for detecting the temperature T _{M (°} C.) of FIG. 2 3 of 7f are read.

Subsequently, the process proceeds to S5, and it is determined whether the amount of intermediate warm water is large or small from the number z of hot water storage temperature sensors that have detected 40 ° C. or more and 60 ° C. or less that is determined as medium warm water read in S4. Specifically, if the number z is 3 or more, it is determined that the amount of medium-temperature water is large, and if YES, the process proceeds to S6, the heating correction coefficient α is set to 0.8, and if the number z is less than 3, the amount of medium-temperature water is It is determined that there is little, and the process proceeds to S7 with NO, and the heating correction coefficient α is set to 0.9. In the present embodiment, there are three hot water storage temperature sensors 7d to 7f that detect the temperature T _M (° C.) in FIG. .8. In this way, by selecting the heating correction coefficient α according to the amount of medium temperature water, the required boiling time H that takes into account the decrease in the heating capacity of the heat pump heating means 2 with respect to the medium temperature water can be calculated, and the unit price of electricity can be ensured. Boiling is completed in an inexpensive midnight time zone, and it is possible to easily determine whether the amount of medium hot water is large or small from the number of hot water storage temperature sensors. Here, it is determined whether the amount of medium hot water is large or small from the number z of hot water storage temperature sensors that detect 40 ° C. or more and 60 ° C. or less, which is determined as medium hot water, but detection of the hot water storage temperature sensors 7a to 7h. The amount of intermediate warm water may be estimated from the temperature, and it may be determined whether the amount of intermediate warm water is large or small.

Next, the required boiling time H is calculated by the following formula in S8. Here, the heating capacity W of the heat pump type heating means 2 is set to 4.5 KW by rating.
Necessary boiling time H = Boiling amount Q / (860 × heating capacity W × heating correction coefficient α)
Boiling amount Q = (tank capacity L−remaining hot water amount L _t )
× (boiling target temperature _{T O} - water supply temperature _T W)
That means
Necessary boiling time H =
(Tank capacity L−remaining hot water amount L _t ) × (boiling target temperature T _O −feed water temperature T _W )
/ (860 × heating capacity W × heating correction coefficient α)
= (370-100) x (90-7) / (860 x 4.5 x 0.8)
= 7.4 hours = 7 hours 24 minutes.

Then, the start time H _S boiling in S9 is calculated by the following equation.
Heating start time H _S = Late night time end time-Necessary boiling time H
= (7:00)-(7 hours 24 minutes)
= 23: 36. Then, it is determined whether the start time H _S boiling the current time at S10, the current time is raised reaches the start time H _S boiling proceeds to S11 YES, the start of the energization of the heat pump type heating means 2 The boiling is started, and it is determined whether or not the temperature detected by the hot water storage temperature sensor 7h is equal to or higher than a preset heating stop temperature in S12. If the temperature is equal to or higher than the heating stop temperature, the process proceeds to S13 with YES, and the heat pump heating means 2 is stopped to stop boiling, and the boiling control is terminated.

  In addition, this invention is not limited only to said one Embodiment, The value of the heating correction coefficient (alpha) according to the number z of the hot water storage temperature sensors which detected 40 degreeC or more and 60 degrees C or less judged to be medium temperature water For example, when the number z is 1, the heating correction coefficient is 0.9, when the number z is 2, the heating correction coefficient is 0.85, and when the number z is 3, the heating correction coefficient is 0.8. It is possible to calculate the required boiling time more suitable for the amount of intermediate warm water by selecting a smaller heating correction factor as the amount of intermediate warm water increases. It can be done.

  In the above embodiment, a heating circuit is connected to the secondary side of the heating heat exchanger 19, but a bath circuit may be connected instead. It has a bath heat exchanger made of a serpentine tube and may be connected to a bath circuit for heating the bath water. Furthermore, the present invention can also be applied to a heat pump type water heater provided with both a heating circuit and a bath circuit.

The schematic block diagram of one Embodiment of this invention. The figure which shows the temperature form of the hot water storage temperature in the hot water storage tank 1 of the same embodiment. The principal part flowchart. The principal part flowchart.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 2 Heat pump type heating means 7a-7h Hot water storage temperature detection means (hot water storage temperature sensor)
18 Control means

Claims (3)

  A hot water storage tank for storing hot water inside, a plurality of hot water storage temperature detecting means for detecting the temperature of hot water in the hot water storage tank provided on the upper and lower sides of the hot water storage tank, and a heat pump heating means for heating the hot water in the hot water storage tank And a control means for calculating a required boiling time based on the amount of boiling and the heating capacity of the heat pump heating means, wherein the control means is a hot water temperature detected by the hot water storage temperature detecting means. Determining the amount of intermediate temperature water in the hot water storage tank, selecting a heating correction coefficient according to the amount of intermediate temperature water, correcting the heating capacity of the heat pump heating means with the selected heating correction coefficient, and A heat pump type water heater characterized by calculating a raising time.   2. The heat pump type hot water heater according to claim 1, wherein the control unit selects a smaller heating correction coefficient as the amount of medium-temperature water increases.   3. The heat pump type hot water heater according to claim 2, wherein the control means determines the amount of medium hot water from the number of the hot water storage temperature detection means that detects a temperature not lower than a first predetermined temperature and not higher than a second predetermined temperature.

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