KR20100114022A - Heat-pump hot-water supply apparatus - Google Patents

Abstract

A heat pump hot water supply device, comprising: a heat pump and a water storage tank for boiling water heated by the heat pump, in order to increase energy efficiency at the time of boiling the storage tank in the late-night time zone and to level the power demand. And means for setting the heating capacity by using the outside temperature and control means for preferentially operating the heat pump at the minimum value of the heating capacity set by the setting means in the late-night time zone, and the control means includes a minimum value of the heating capacity. When boiling cannot be completed in the midnight time zone even if the furnace heat pump is preferentially operated, the heat pump is operated to be operated with a heating capacity higher than the minimum of the heating capacity.

Description

Heat Pump Hot Water Supply Unit {HEAT-PUMP HOT-WATER SUPPLY APPARATUS}

The present invention relates to a heat pump hot water supply device configured to heat water in a storage tank using a heat pump.

There is a thing described in patent document 1 as an example of the low-heat-type heat pump hot water supply apparatus which boils water in the late night time slot which electric cost is cheap. In order to boil water in the late night time zone and to reduce the heat dissipation loss, the required boiling time is calculated based on the required boiling heat amount and the constant heating capacity of the heat pump, and the time required by subtracting the required boiling time from the late night time zone end time. Is set to the boiling start time, and boiling operation is shifted in the latter half of the late night time zone.

As an example of the heat pump hot water supply apparatus provided with another boiling control means, there exist some described in patent document 2. As shown in FIG. This calculates the heating capacity of the inverter heat pump by (necessary calorie | heat amount / stirring time), and calculate | requires a corresponding frequency from the graph which shows the relationship of a heating capacity and a frequency. Inverter heat pumps are more efficient than those operating at higher frequencies. Therefore, the low temperature water can be performed with high efficiency as compared with the case of boiling water at a constant output.

In addition, Patent Document 3 describes an example of a heat pump hot water supply device having a small water storage tank. This is mainly to store the hot water in the storage tank by driving the heat pump cycle at night, and to store the hot water in the storage tank by appropriately driving the heat pump cycle even during the day, when there is a risk of running out of hot water, heating of the heat pump cycle In order to give priority to the operation which raises a capability, the hot water is prevented, and when there is no fear of hot water being cut off, operation which prioritized the operation efficiency of a heat pump cycle is performed, preventing hot water interruption and improving operation efficiency. Then, the time zone timer gives priority to the heating capacity in order to prevent the hot water being cut off during the time zone (16 to 22:00) that requires the most hot water throughout the day, and the operation efficiency in the other time zones.

Japanese Patent Application Laid-Open No. 2004-347171 Japanese Patent Application Laid-open No. Hei 9-68369 Japanese Patent Application Publication No. 2005-127588

In the heat pump hot water supply apparatus described in Patent Document 1, the influence of the energy efficiency of the heat pump on the change of the outside air temperature in the late night time zone is not considered. The heat pump has a characteristic that the higher the outside temperature, the higher the COP, which is the ratio of the water heating capacity to the power consumption of the heat pump, so-called energy efficiency. When the late night time zone is, for example, 11 pm to 7:00 am, the outside temperature shows a substantially downward change from 11 pm, the late night time zone start time, to 7 am, the late night time zone end time. Accordingly, there is a problem that the energy efficiency (COP) is lowered because the heat pump is operated in the late night time zone where the outside air temperature is lowered by shifting the boiling operation in the second half of the late night time zone.

Moreover, in the heat pump hot water supply apparatus described in patent document 2, the frequency of the heat pump to operate is determined from the graph which shows the relationship of the heating capability and frequency computed by (necessary heat quantity / boiling time). When the COP of the heat pump has a constant compressor efficiency or a small decrease in the compressor efficiency due to a decrease in the frequency, the one operating at a lower frequency like the heat pump hot water supply device described in Patent Document 2 operates at a higher frequency. Energy efficiency is higher than that.

By the way, carbon dioxide is used as a refrigerant | coolant of the heat pump hot water supply apparatus currently commercialized. Carbon dioxide has a high and low pressure differential pressure of 3 times, a cylinder volume of 1/3, and a discharge pressure of about 3 times that of fluorocarbons (Heat Pump & Heat Storage Center, p.50, Omsa, 2004. 2 Issued January 1). As described above, since a compressor using carbon dioxide as a refrigerant has a high pressure difference of three times higher than that of fluorocarbon, the effect of leakage of the compression chamber increases with the decrease in the frequency of the compressor, and the decrease in the compressor efficiency increases. Therefore, in the heat pump hot water supply device using carbon dioxide as the refrigerant, the lower the frequency, the higher the energy efficiency, and there is a frequency at which the energy efficiency is the highest. That is, the patent document 2 does not consider the boiling control means in the case where the frequency with the highest energy efficiency exists.

Moreover, although the heat pump hot water supply apparatus of patent document 3 is made to switch between operation which gave priority to heating capability, and operation which gave priority to operation efficiency, it does not consider about the control means of switching of operation in a late night time zone.

An object of the present invention is to obtain a heat pump hot water supply apparatus capable of maintaining high energy efficiency and contributing to leveling of electric power demand.

In order to achieve the above object, the present invention provides a heat pump hot water supply device having a heat pump and a water storage tank for boiling water heated by the heat pump, comprising: setting means for setting a heating capacity using an outside temperature; And a control means for preferentially operating the heat pump at the minimum value of the heating capacity set by the setting means in the late-night time zone, and the control means only operates the heat pump preferentially at the minimum value of the heating capacity. When boiling cannot be completed in the late night time zone, the heat pump is operated to be operated with a heating capacity higher than the minimum value of the heating capacity.

According to the present invention, the control of operating the heat pump with a heating capacity of which energy efficiency is substantially the highest at a predetermined time period during which the power demand is low during a late night time period with low electric charges is preferred, so that the energy efficiency at the time of tank boiling can be improved. At the same time, it is possible to obtain a heat pump hot water supply apparatus that can contribute to leveling of electric power demand.

Other objects, features and advantages of the present invention will become apparent from the following description of the embodiments of the present invention taken in conjunction with the accompanying drawings.

1 is a system diagram of a heat pump hot water supply device according to a first embodiment of the present invention.
Fig. 2 is a flowchart showing a night boiling control according to the first embodiment of the present invention.
Fig. 3A is a diagram showing the relationship between the minimum and maximum values of the outside air temperature and the heating capacity of the heat pump unit when the boiling temperature target value in the first embodiment of the present invention is 70 ° C or higher.
Fig. 3B is a diagram showing the relationship between the minimum and maximum values of the outside air temperature and the heating capacity of the heat pump unit when the boiling temperature target value in the first embodiment of the present invention is less than 70 ° C.
4 is a diagram showing a relationship between a heating capacity and a COP of a heat pump unit according to the first embodiment of the present invention.
Fig. 5A is a diagram showing the time of heat pump operation in the first embodiment of the present invention.
Fig. 5B is a diagram showing the time of heat pump operation in the first embodiment of the present invention.
Fig. 5C is a diagram showing the time of heat pump operation in the first embodiment of the present invention.
Fig. 6 is a flowchart showing the heating capability reset control of the heat pump unit in the second embodiment of the present invention.
Fig. 7 is a flowchart showing late night boiling control in the third embodiment of the present invention.
Fig. 8A is a diagram showing the relationship between the minimum and maximum values of the outside air temperature and the heating capacity of the heat pump unit when the boiling temperature target value in the fifth embodiment of the present invention is 70 ° C or higher.
Fig. 8B is a diagram showing the relationship between the minimum and maximum values of the outside air temperature and the heating capacity of the heat pump unit when the boiling temperature target value in the fifth embodiment of the present invention is less than 70 ° C.

EMBODIMENT OF THE INVENTION Hereinafter, the 1st Example of the heat pump hot water supply apparatus which concerns on this invention is described based on drawing.

(First embodiment)

1 is a system diagram of a heat pump hot water supply device 100.

The heat pump hot water supply device 100 includes a water storage tank unit 1 and a heat pump unit 2. The water storage tank unit 1 includes a water storage tank 11, a tapping pipe 12 connected to the top of the water storage tank 11, a water supply pipe 13 connected to one of the bottom of the water storage tank 11, and A water supply metal member 14 connected to the other side of the water supply pipe 13 and connected to a water supply outside the apparatus, a pressure reducing valve 15 for adjusting a constant introduced from the water supply metal member 14 to an appropriate water pressure, and a discharge A hot water mixing valve 17 for mixing hot water from the hot water pipe 12 and low temperature water from the water supply branch pipe 16 branched from the water supply pipe 13, and one side is connected downstream of the hot water mixing valve 17. And a hot water supply metal member 20 connected to a hot water supply terminal outside the apparatus, and a hot water supply pipe 18 including a hot water flow rate sensor 19 therebetween.

In addition, the storage tank 11 is connected to the heat pump flow pipe 21 in which one is connected to the lower storage tank 11 lower part, and the other is connected to the heat pump unit 2, and the upper part of the storage tank 11 upper part. On the other hand, the other side is provided with the heat pump return pipe 22 connected with the heat pump unit 2, and the low temperature water in the storage tank 11 is comprised so that circulation is possible through the heat pump unit 2. As shown in FIG.

The plurality of tank temperature sensors 30 provided on the side of the water storage tank 11, the water supply temperature sensor 31 installed on the water supply pipe 13, and the hot water supply temperature sensor 32 installed on the hot water supply pipe 18 detect the temperature of each part. The temperature information is sent to the storage tank control unit 23, and the storage tank control unit 23 communicates with the heat pump control unit 58 and the remote controller (not shown) which will be described later, and controls the storage tank unit 1 at the same time. Is done.

The heat pump circuit 3 of the heat pump unit 2 is a compressor 51 for compressing a refrigerant to be a high temperature refrigerant, and is supplied from the refrigerant and the boiling water tank unit 1 compressed by the compressor 51 to a high temperature. Water refrigerant heat exchanger (52) for exchanging water, expansion valve (53) for depressurizing the refrigerant exiting the water refrigerant heat exchanger (52), and evaporator (54) for evaporating the low temperature low pressure refrigerant from the expansion valve (53). Is connected by a refrigerant pipe. By using carbon dioxide as the refrigerant, hot water can be boiled.

The compressor 51 is capable of capacity control by inverter control, and the rotation speed is variable from low speed to high speed. The evaporator 54 is an air refrigerant heat exchanger and heat exchanges a large amount of outdoor air with a reduced pressure refrigerant by an outdoor fan 55.

The water refrigerant heat exchanger 52 has a refrigerant side heat exchanger tube 52a and a water side heat exchanger tube 52b, and is opposed to the flow of the refrigerant in the refrigerant side heat transfer tube 52a and the water flow in the water side heat transfer tube 52b. . And the high temperature and high pressure refrigerant | coolant and low temperature water heat-exchange. That is, when water which is low temperature passes through the water-side heat pipe 52b at the inlet of the water refrigerant heat exchanger 52 (lower side of the water refrigerant heat exchanger 52 in the drawing), the water refrigerant heat exchanger 52 is gradually heated. Is heated up to the predetermined temperature set by the heat pump control part 58 mentioned later at the exit (upper side of the water refrigerant heat exchanger 52 in drawing).

The tank circulation pump 56 and the water refrigerant heat exchanger water flow rate sensor which are connected to the inlet side of the water side heat exchanger tube 52b of the water refrigerant heat exchanger 52 and the above-mentioned heat pump flow tube 21, and are capable of volume control in the course of the pipeline. 57 is disposed. Further, the outlet side of the water side heat transfer pipe 52b and the heat pump return pipe 22 described above are connected.

Water refrigerant heat exchanger water installed in the compressor discharge temperature sensor 35 installed in the refrigerant pipe on the outlet side of the compressor 51, the outside air temperature sensor 36 installed in the air inlet side of the evaporator 54, and the heat pump flow pipe 21. The water refrigerant heat exchanger water outlet temperature sensor 38 provided in the inlet temperature sensor 37 and the heat pump return pipe 22 detects the temperature of each part, and sends the detected temperature information to the heat pump control unit 58, The heat pump control unit 58 communicates with the above-described storage tank control unit 23 and simultaneously controls the heat pump unit 2.

The operation at the time of the hot water supply will be described below. When the hot water supply terminal (not shown) connected to the hot water supply metal member 20 is opened, the hot water of the upper portion of the hot water tank 11 is introduced into the hot water supply pipe 12 by the water pressure of the water supply connected to the water supply metal member 14. Further, low temperature water supply flows into the water supply branch pipe 16, and the high temperature water and the low temperature water flow out from the hot water supply terminal via the hot water mixing valve 17, the hot water flow rate sensor 19, and the hot water metal member 20. At that time, the flow rate sensor 19 detects the water flow, and the hot water tank control unit 23 performs the hot water supply pipe 12 so that the temperature detected by the hot water temperature sensor 32 becomes the hot water temperature set by the remote controller (not shown). The ratio of the hot water from) and the cold water from the feedwater branch pipe 16 is controlled. As hot water above the water storage tank 11 is used, a low temperature water supply is supplied to the water storage tank 11 lower portion.

The operation at the time of boiling will be described below. When boiling water in the storage tank 11 is boiled, the heat pump control unit 58 controls the heat pump circuit 3 and controls the tank circulation pump 56. At this time, as will be described later, the rotational speed control of the compressor 51, the opening degree control of the expansion valve 53, and the rotational speed control of the tank circulation pump 56 are performed. The reservoir water flowing out from the bottom of the storage tank 11 by the operation of the tank circulation pump 56 flows into the water refrigerant heat exchanger 52 through the heat pump flow pipe 21, and the high temperature of the heat pump circuit 3 is increased. Is heated to the upper portion of the water storage tank 11 through the heat pump return pipe 22 to store hot water.

Next, the operation of the night boiling control will be described with reference to FIGS. 2 to 4. The late night time zone is a time when the electricity bill becomes cheaper, for example, from 11 pm to 7 am. In the flowchart of late night boiling control of FIG. 2, the storage tank control part 23 starts a late night boiling control at 11 pm which is the start time of a late night time zone (S1). First, boiling heat quantity Qa is set (S2). The boiling calorie Qa is calculated as the sum of the mean, standard deviation and preliminary calories for the past 7 days.

The calorific value Qc of one day (from 11:00 pm of the day before to 11:00 pm of the day) is calculated by the following formula.

(Equation 1)

Qc = Qz1 + Qd-Qz

Here, Qz1 is the residual heat amount of the storage tank 11 at 11 pm of the previous day, Qd is the heating amount of the heat pump unit 2, and Qz is the residual heat amount at 11 pm of the day. The residual heat quantities Qz1 and Qz include the temperature difference between the temperature detected by each tank temperature sensor 30 of the water storage tank 11 and the temperature detected by the water supply temperature sensor 31, and each tank temperature sensor 30. It is computed by the sum of the volume of the water storage tank 11 divided into the up-down direction, and the product of the density of a water, and a specific heat | fever. In addition, heating amount Qd is computed as the integral value of the running time of the setting value (required heating capability) of the heating capability of the heat pump unit 2 mentioned later.

The storage tank control unit 23 stores the calories of use for the past 7 days to obtain an average value and a standard deviation, and sets the boiling calorific value Qa as the sum of the average value, the standard deviation and the preliminary calorific value in consideration of the variation in the calorific value of the use. The preliminary calorie value is, for example, a calorific value of a hot water supply temperature of 42 ° C. and a hot water supply amount of 100 L.

Next, the boiling temperature target value tp is set (S3). The boiling temperature tp is calculated by the following formula.

(Equation 2)

tp = Qa / (ρcVVα) + twi

However, in order to prevent the Legionella bacteria generation, when the calculated boiling temperature target value tp is less than 65 degreeC, it sets to 65 degreeC. Here, Qa is the above-described boiling heat amount, ρ is the water density, c is the water specific heat, V is the volume of the storage tank 11, α is the volumetric efficiency, twi is the water supply temperature detected by the water supply temperature sensor 31 of FIG. to be. The volumetric efficiency (α) is a boiling tank because the water inlet temperature of the water refrigerant heat exchanger (52) stops boiling at a temperature lower than the boiling temperature (tp), for example, 55 ° C., for the protection of the heat pump circuit 3. (11) It is considered that the temperature at the bottom does not become the boiling temperature tp.

Next, the boiling time Tn is set (S4). As described above, the night time zone is 8 hours from 11 pm to 7 am. The boiling time Tn is set to 5 hours, for example. These five hours are from 1:00 am to 6:00 am when the demand for electricity is low during the late night hours. The boiling time Tn may be changed depending on the season (calendar), for example, in consideration of the amount of power demand for each season.

Next, the minimum value Wmin and the maximum value Wmax of the heating capacity of the heat pump unit 2 are set (S5). 3A and 3B show the relationship between the minimum temperature (Wmin) and the maximum value (Wmax) of the outside air temperature and the heating capacity when the boiling temperature target value tp is 70 ° C or more and less than 70 ° C. In other words, the minimum value Wmin and the maximum value Wmax of the heating capacity can be determined from the boiling temperature target value tp and the outside temperature (detected value of the outside temperature sensor 36). In FIG. 3B, when the boiling temperature target value is less than 70 ° C. and the outside temperature is ta, the relationship between the heating capacity of the heat pump unit 2 and the COP (the ratio of the heating capacity to the power consumption) is shown in FIG. 4. The heating capacity is mainly changed by changing the rotational speed (frequency) of the compressor 51. The heat pump unit 2 exhibits the characteristic that the COP has the highest value for the heating capability. And the minimum value of the heating capability of the heat pump unit 2 shown in FIG. 3B is made into the heating capability at which COP shown in FIG. 4 becomes the highest. In addition, the maximum value of the heating capacity of FIG. 3B is the heating capacity which completes boiling at 8 hours of a late night time zone even if there is no hot water supply in a midnight time zone at each outside temperature. Therefore, in FIG. 3B, the operation with a smaller heating capacity is higher than the operation with a large heating capacity.

Next, the required heating capacity W of the heat pump unit 2 is calculated (S6). The required heating capacity W is calculated by the following formula.

(Equation 3)

W = (Qa-Qz) / (Tn, β)

Here, Qa is the above-mentioned boiling heat amount, Qz is the remaining heat amount at 11 pm on the same day, Tn is the above-mentioned boiling time, and β is heating efficiency. The heating efficiency β is determined by the defrosting operation when the heating capacity is not satisfied at the required heating capacity W at the start of boiling of the heat pump unit 2 or near the completion of boiling, or when the outside air temperature is low. In consideration of the decrease in the average heating capacity, the value is set according to the outside air temperature.

Next, it is determined whether the calculated required heating capacity W is within the range of the minimum value Wmin and the maximum value Wmax of the heating capacity of the heat pump unit 2 set in step S5, and is necessary for each case. The process is performed (S7 to S15).

When the required heating capacity (W) is less than the minimum value (Wmin) of the heating capacity set in step S5 (YES in S7), the required heating capacity (W) is set to the minimum value (Wmin) (S8), and is reversed to the changed necessary heating capacity. The boiling time Tn is calculated (S9). At this time, the boiling time Tn is calculated by the following formula.

(Equation 4)

Tn = (Qa-Qz) / (W.β)

By this calculation, the boiling time Tn becomes shorter than the value set in step S4 and 5 hours. Therefore, it is possible to complete boiling during the period from 1 AM to 6 AM when the power demand is small during the late night time zone.

Next, the end time shift time Tf is set (S10). At this time, the end time shift time Tf is set to 1 hour in order to shift the boiling end time from 7:00 am at the end time of the late-night time zone to 6 am with less power demand.

When the required heating capacity (W) is equal to or greater than the minimum value (Wmin) of the heating capacity set in step S5 (No in S7), and when it is larger than or equal to the maximum value (Wmax) (Yes in S11), the required heating capacity (W) is set to the maximum value (Wmax). (S12), the boiling time Tn is calculated inversely based on the changed necessary heating capacity (S13). At this time, the boiling time Tn is computed by the same formula as Formula 4. By this calculation, the boiling time Tn becomes longer than the value set in step S4 and 5 hours. Therefore, it is not possible to complete boiling only during the period from 1:00 am to 6:00 am when power demand decreases in the late-night time zone, and during other 6 am to 7:00 am and from 11 pm of the day before to 1 am of the next day It is necessary to carry out boiling operation even until time.

Next, the end time shift time Tf is set (S14). At this time, the end time shift time Tf is set to 0 hours in order not to shift the boiling end time but to be 7 AM at the end time of the late night time zone.

When the required heating capacity W is within the range of the heating capacity set in step S5 (No in S11), the boiling time Tn remains the value set in step S4 for 5 hours, and the amount of power demand decreases in the late night time zone. It is possible to complete the boiling from 1 am to 6 am.

At this time, the end time shift time Tf is set (S15). The end time shift time Tf is set to one hour in order to shift the boiling end time from 7:00 am at the end of the late night time zone to 6 am with less demand.

As described above, after the boiling time Tn and the required heating capacity W are determined in steps S7 to S15, the boiling start time Ts is set (S16). The boiling start time Ts is calculated by the following formula.

(Eq. 5)

Ts = late night time zone end time-Tf-Tn

Here, Tf is the end time shift time described above, and Tn is the boiling time. In addition, the late-night time zone end time is 7:00 AM.

Next, a determination is made as to whether the current time is the boiling start time Ts (S17). If the current time is the boiling start time Ts (YES), the heat pump is operated (S18). If the current time is not the boiling start time Ts (YES), step S17 The determination of is repeated.

Heat pump operation S18 is performed as follows. At this time, the storage tank control part 23 issues a heat pump operation command to the heat pump control part 58, and provides the boiling temperature target value tp and the value of required heating capability W. As shown in FIG. The heat pump control unit 58 controls the rotation speed of the compressor 51 so that the water outlet temperature detected by the water outlet temperature sensor 38 of the water refrigerant heat exchanger 52 becomes the boiling temperature target value tp.

The heat pump control unit 58 also controls the opening degree of the expansion valve 53 so that the discharge temperature detected by the compressor discharge temperature sensor 35 becomes the target value td0 calculated by the following equation.

(Equation 6)

Td0 = f (tp, thwi, ta, W)

Where tp is the boiling temperature target value, thwi is the water inlet temperature detected by the water inlet temperature sensor 37 of the water refrigerant heat exchanger 52, ta is the outside air temperature detected by the outside air temperature sensor 36, and W is the required heating capability. And the target value td0 of the discharge temperature is represented by their function f. The target value is set to the discharge temperature at which the COP of the heat pump unit 2 becomes approximately the highest. Here, since the target value is a function of the required heating capacity W, the high efficiency heat pump can be operated in the entire range of the minimum value Wmin and the maximum value Wmax of the heating capacity shown in FIG. 3B.

In addition, the heat pump control unit 58 rotates the speed of the tank circulation pump 56 so that the water flow rate detected by the water flow rate sensor 57 of the water refrigerant heat exchanger 52 becomes the target value Lw0 calculated by the following equation. Control is performed.

(Eq. 7)

Lw0 = W / [(ρc) (tp-thwi)]

Where W is the required heating capacity, ρ is the water density, c is the specific heat of heat, tp is the boiling temperature target value, and thwi is the water inlet temperature detected by the water inlet temperature sensor 37 of the water refrigerant heat exchanger 52.

The heat pump control part 58 performs the boiling operation whose boiling temperature is tp and heating capability W by the rotation speed control of the compressor 51 and rotation speed control of the tank circulation pump 56 mentioned above.

During the heat pump operation, the water storage tank control unit 23 determines whether the predetermined tank temperature sensor 30 is equal to or higher than the preset boiling end temperature (S19). If it is not above the boiling end temperature (No in S19), the determination of Step S19 is repeated. When the boiling end temperature is equal to or higher (YES), the storage tank control unit 23 issues a heat pump stop command to the heat pump control unit 58 (S20), and completes the late night boiling (S21). In addition, in order to calculate the above-mentioned heating amount Qd, the time integration of the required heating capacity W is calculated during the heat pump operation.

As described in detail above, the night boiling operation is divided into three patterns (see FIGS. 5A to 5C). That is, the first (FIG. 5A) is a heating in which the efficiency of the heat pump is approximately the highest during a late night time period (11 pm to 7 am) and at a predetermined time period (1 am to 6 am) when the power demand is small. The ability to drive a heat pump with the ability. At this time, the time which subtracted the required boiling time from the predetermined time zone end time (6 AM) is set as a boiling start time, and boiling operation is shifted to the latter half of a predetermined time zone.

Second (FIG. 5B) is a case where boiling cannot be completed in a predetermined time period only by operation with a heating efficiency of approximately the highest efficiency. This is to operate the heat pump with a heating capacity higher than the heating capacity at which the efficiency of the heat pump becomes approximately the highest so that boiling is completed in a predetermined time period. At this time, the heat pump is operated with the heating capability to complete boiling using approximately the entire time of the predetermined time zone (1 am to 6 am).

Third (FIG. 5C) is a case where boiling cannot be completed in a predetermined time period even when driving at the maximum heating capacity. Operate the heat pump with maximum heating capacity to ensure boiling is complete at night time. At this time, the time which removed the required boiling time from the late night time zone end time (7 AM) is set as a boiling start time, and boiling operation is shifted to the latter half of a late night time zone.

In addition, in the present embodiment, it has been explained that the boiling is completed at the predetermined time zone end time or the late night time zone end time, but, for example, the heating capacity of the heat pump is reset slightly so that the boiling is completed with a margin before this time, The driving time may be shortened slightly.

According to the first operation pattern, the heat pump is operated with the heating capacity at which the efficiency of the heat pump becomes approximately the highest, so that the heat pump hot water supply device can be operated with high efficiency.

In addition, since the heat pump is operated for a long time with a small heating capacity by the first and second driving patterns, the boiling operation start time of the heat pump is accelerated, and the operating time in the time zone where the outside air temperature is high in the driving late-night time zone is increased. The pump can be operated under conditions of increased energy efficiency.

In addition, since the heat pump operation is performed within a predetermined time period from 1 AM to 6 AM when the demand for power decreases in the late night time zone, the first and second driving patterns can contribute to leveling the power demand.

In addition, according to the third driving pattern, the boiling can be surely completed in the midnight time zone even when the boiling heat amount is large.

(2nd Example)

A second embodiment of the present invention will be described with reference to FIG. This embodiment differs from the first embodiment in the heat pump operation in step S18 of the late-night boiling control flowchart shown in FIG. 2. In this embodiment, the heat capacity of the heat pump is set at each constant time.

The storage tank control unit 23 starts the reset control of the heating capacity during the heat pump operation (S30). If the current heating capacity is less than the maximum value Wmax (Yes S31), the heating capacity is reset, and if the maximum heating power Wmax (S31 NO), control is terminated without resetting the heating capacity (S32). That is, when the heat pump operation is performed within a predetermined time period from 1 am to 6 am, the heating capacity is reset.

To reset the heating capacity, first, the current amount of heat Qx is calculated (S33). The current heat quantity Qx is a storage tank including a temperature difference between a temperature detected by each tank temperature sensor 30 of the storage tank 11 and a temperature detected by the water supply temperature sensor 31, and each tank temperature sensor 30. Calculated by the sum of the volume divided by (11) in the vertical direction and the product of the density of water and the specific heat.

Next, the boiling remaining time Tr is calculated (S34). The boiling remaining time Tr is calculated by the following formula.

(Eq. 8)

Tr = late night time zone end time-Tf-Current time

Here, the late-night time zone end time is 7:00 am, and Tf is the end time shift time, which is one hour set in step S10 or S15 in FIG.

Next, the minimum value Wmin and the maximum value Wmax of the heating capacity of the heat pump unit 2 are set (S35). The setting method is the same as that in step S5 of FIG.

Next, the required heating capacity W of the heat pump unit 2 is calculated (S36). The required heating capacity W is calculated by the following formula.

(Eq. 9)

W = (Qa-Qx) / (Tr, β)

Here, Qa is the boiling heat amount described in the first embodiment, Qx is the current calorie value described above, Tr is the boiling time remaining described above, and β is the heating efficiency described in the first embodiment.

Next, it is determined whether the calculated required heating capacity W is within the range of the minimum value Wmin and the maximum value Wmax of the heating capacity of the heat pump unit 2 set in step S35, and when necessary, the necessary processing is performed. (S37 to S40). When the required heating capacity W is less than the minimum value Wmin of the heating capacity set in step S35 (Yes S37), the required heating capacity W is set to the minimum value Wmin (S38). In addition, when the required heating capacity W is larger than the maximum value Wmax (Yes S39), the required heating capacity W is set to the maximum value Wmax (S40). In addition, in the case of the step S39 example, since the required heating capacity is suppressed to the maximum value Wmax, the boiling is not completed until 6 AM, which is the predetermined time zone end time, but the time excess is small and boils until 7 AM of the late night time zone end time. Is complete.

Next, the required heating capacity W is reset (S41). At this time, the storage tank control part 23 gives the heat pump control part 58 the value of a new required heating capability W. FIG. The heat pump control unit performs operation control of the heat pump unit 2 based on the new required heating capacity W.

The storage tank control unit 23 performs the reset control of the above heating capability every time the timer passes (S42).

By setting the heat capacity of the heat pump delicately and precisely at regular intervals, the heat pump hot water supply device is set up with the smallest possible heating capacity within a predetermined time period from 1 AM to 6 AM when the power demand is low during the late night time. Can operate with efficiency. Moreover, boiling can be completed reliably within a predetermined time slot.

(Third Embodiment)

A third embodiment of the present invention will be described with reference to FIG. In this embodiment, in the late-night boiling control of the first embodiment, the boiling time Tn is changed from 5 hours to 8 hours. In Fig. 7, the same steps as those in Fig. 2 are denoted by the same reference numerals and description thereof will be omitted.

Steps S1 to S3 are the same as in the first embodiment. The boiling time Tn of step S4 'is set to 8 hours of a late-night time zone (11 pm-7 am). In step S6, the boiling time Tn is set to 8 hours and the required heating capacity W is calculated.

In step S7 ', when the required heating capability W is less than the minimum value Wmin of the heating capability set in step S5 (YES in S7'), the required heating capability W is made into the minimum value Wmin (S8), The boiling time Tn is calculated inversely based on the changed necessary heating capacity (S9).

In other cases (S7 'NO), it is assumed that the required heating capacity W is within the range of the heating capacity set in step S5, and the same value is used. In addition, as described in the first embodiment, the maximum value Wmax of the heating capacity of FIG. 3 is the heating capacity at which boiling is completed at 8 hours in the late night time zone even when there is no hot water supply in the late night time zone at each outside temperature. Therefore, the required heating capacity W becomes a value below the maximum value Wmax.

Subsequent steps S16 to S21 are the same as in the first embodiment.

As mentioned above, by setting the boiling time of a heat pump to 8 hours longer than 5 hours, a heat pump hot water supply apparatus can be operated with a smaller heating capacity with respect to the same required boiling heat quantity, and high efficiency can be maintained.

(Example 4)

A fourth embodiment of the present invention will be described. This embodiment differs from the third embodiment in that the heat pump operation in step S18 of the flowchart of the late-night boiling control shown in FIG. In this embodiment, the multiplied by the coefficient k for the required heating capacity W of the heat pump is the heating capacity for the heat pump to operate.

The coefficient k is calculated by the following formula.

(Eq. 10)

k = 1 + d-2d / Tn * T

Here, d is a shift value, Tn is a boiling time for 8 hours, and T is a heat pump operation time. The coefficient k is a linear function of the operating time T, where k = 1-d when T = 0, k = 1 + d, and T = Tn. In other words, by multiplying the coefficient k by the required heating capacity W, the heating capacity of the heat pump becomes larger than the required heating capacity W in the first half of the late-night time zone and becomes smaller than the required heating capacity W in the second half. In addition, when it boils for 8 hours (in the case of no in step S7 'of FIG. 7,), this control process is performed. In addition, the heat capacity of a heat pump shall be in the range from the minimum value Wmin set to FIG. 3 to the maximum value Wmax.

According to the above-described control, since half or more of the boiling heat of the late night is boiled in the first half of the late night time zone, it is possible to operate under the condition that the energy efficiency of the first half of the high outside air temperature is high during the late night time zone, thereby maintaining high efficiency.

(Fifth Embodiment)

The fifth embodiment of the present invention will be described. This embodiment differs from the third embodiment in the method of setting the heating capacity minimum value Wmin in step S5 of the flowchart in the late-night boiling control of FIG. 7. In this embodiment, the heating capacity minimum value Wmin of the heat pump is set to approximately two thirds of the heating capacity maximum value Wmax.

8A and 8B show the relationship between the outside air temperature and the minimum value and the maximum value of the heating capacity of the heat pump unit 2 when the boiling temperature target values in the present embodiment are 70 ° C or more and less than 70 ° C, respectively. Approximately two thirds of the maximum value Wmax, which is greater than the minimum value Wmin of the heating capacity, which is greater than the minimum value Wmin indicating the heating capacity at which the efficiency of the heat pump shown in FIGS. 3A and 3B of the first embodiment becomes approximately the highest. It is set as (66%). At this time, within 66% to 100% of the maximum heating capacity of the heat pump, the smaller the heating capacity, the higher the energy efficiency.

This control process causes the heat pump unit 2 to boil from 66% of the maximum heating capacity to 100% of the maximum heating capacity in the late night time zone, and to operate at least 66% of the maximum heating capacity at least, compared with the third embodiment. The boiling time Tn calculated in step S9 of the flowchart of FIG. 7 becomes small, and therefore, the boiling start time Ts calculated in S16 is shifted to the rear of the late night time zone.

According to the above-described control, while maintaining high energy efficiency, it is possible to suppress an increase in the amount of power in the first half with high electric power demand during the late night time zone.

In the present embodiment, the heating capacity minimum value Wmin of the heat pump is set to approximately two thirds of the heating capacity maximum value Wmax, but the same effect is obtained even when it is set to 50% to 80%.

In the above embodiment, the nighttime time zone is a time when the electric charge becomes cheaper. However, the present invention can be similarly implemented even in a time zone where the hot water supply demand or the electric power demand is small.

In addition, in the above embodiment, in order to obtain the required heating capacity, the rotational speed control of the compressor is performed so that the boiling temperature becomes the target value, and the rotational speed control of the tank circulation pump is performed so that the quantity is the target value. From the relationship, the rotational speed of the tank circulating pump may be controlled so that the rotational speed is set so that the boiling temperature is a target value, and a control method in which an outline of the required heating capability can be obtained.

According to the present invention, priority is given to control of operating the heat pump with a heating capacity of which energy efficiency is approximately the highest at a predetermined time period, so that the energy efficiency at the time of tank boiling operation of the heat pump hot water supply device is increased.

Although the foregoing description has been made with respect to the examples, it is apparent to those skilled in the art that various changes and modifications can be made within the spirit of the invention and the scope of the appended claims.

Claims (12)

With heat pump,
A heat pump hot water supply device having a hot water tank for storing water heated by the heat pump,
Setting means for setting the heating capacity by using the outside temperature, and control means for preferentially operating the heat pump with a heating capacity such that the energy efficiency of the heat pump is substantially the highest at night time,
The control means is characterized in that the energy efficiency is substantially highest when boiling cannot be completed in the late-night time period only by preferentially operating the heat pump with a heating capacity such that the energy efficiency of the heat pump is substantially the highest. And controlling the heat pump to operate with a heating capability higher than the heating capability. With heat pump,
A heat pump hot water supply device having a hot water tank for storing water heated by the heat pump,
Setting means for setting the heating capacity by using the outside temperature;
And a control means for preferentially operating the heat pump at the minimum value of the heating capacity set by the setting means in the late night time zone,
The control means operates the heat pump with a heating capacity higher than the minimum of the heating capacity when boiling cannot be completed in the late-night time zone only by preferentially operating the heat pump with the minimum of the heating capacity. A heat pump hot water supply apparatus, characterized in that the control to make. The heat pump hot water supply apparatus according to claim 2, wherein the control means includes setting means for setting a minimum value of the heating capacity to a heating capacity at which the energy efficiency is substantially maximum. The heat pump hot water supply apparatus according to claim 2, wherein the control means includes setting means for setting the minimum value of the heating capacity to a heating capacity larger than the heating capacity at which the energy efficiency becomes substantially maximum. The heat pump hot water supply apparatus according to claim 2, wherein the minimum value of the heating capacity is set to 50 to 80% of the maximum value of the heating capacity. The heat pump hot water supply apparatus according to claim 2, wherein the control device controls to boil at least half of the total boiling heat of the late night time zone in the first half of the late night time zone. With heat pump,
A heat pump hot water supply device having a hot water tank for storing water heated by the heat pump,
Setting means for setting the heating capacity by using the outside temperature;
Control means for preferentially operating the heat pump with a heating capability such that the energy efficiency of the heat pump is substantially the highest at a predetermined time period in the late night time zone;
Control means for operating the heat pump with a heating capacity higher than the heating capacity at which the energy efficiency is substantially highest, when boiling cannot be completed in the predetermined time period only by an operation in which the energy efficiency of the heat pump is substantially highest;
When the boiling cannot be completed in the predetermined time period even when driving at the maximum value of the heating capacity set by the setting means, the heat pump hot water supply device, characterized in that the control means for operating the heat pump also in the night time zone. . 8. The control apparatus according to claim 7, further comprising control means for operating the heat pump with a heating capacity greater than the heating capacity at which energy efficiency becomes substantially highest during the late night time zone when boiling cannot be completed at the predetermined time period. A heat pump hot water supply device, characterized in that. 8. The heat pump hot water supply device according to claim 7, characterized in that a control means for operating the heat pump with maximum heating capacity is provided in the late night time zone when boiling cannot be completed in the predetermined time zone. The heat pump hot water supply apparatus according to claim 1, further comprising setting means for setting a heating capacity of the heat pump at a predetermined time within a late night time zone. The heat pump hot water supply apparatus according to claim 1, further comprising a water storage tank control unit and a heat pump control unit in which a command of heating capacity is transmitted from the water storage tank control unit. The heat pump hot water supply apparatus according to claim 1, wherein carbon dioxide is used as a refrigerant of the heat pump.

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