JP6913785B2 - Hot water supply system - Google Patents

Description

The present invention relates to a hot water supply system provided with a heat pump type heating means capable of supplying hot water to a hot water storage tank.

There is a hot water supply system equipped with a hot water storage tank for storing hot water, a heat pump type water heater capable of supplying hot water to the hot water storage tank, and a gas water heater capable of heating hot water supplied from the hot water storage tank to a hot water supply terminal. In this hot water supply system, a heat pump type water heater is independently operated to perform a boiling operation in a state where hot water is not discharged. On the other hand, if the hot water runs out while the hot water is being discharged, the heat pump type water heater and the gas water heater are operated at the same time to perform the boiling operation.

Japanese Unexamined Patent Publication No. 2013-11495

The heat pump type water heater is generally operated at a heating capacity (frequency) that maximizes the heat pump efficiency (COP) according to the outside air temperature. This means that the COP is maximized regardless of whether the heat pump type water heater is operated independently to perform the boiling operation or the heat pump type water heater and the gas water heater are operated simultaneously to perform the boiling operation. It is operated at the heating capacity (frequency). In this case, when the hot water runs out, it may not be optimal as the overall energy efficiency of the system including the heat pump type water heater and the gas water heater.

Therefore, an object of the present invention is to provide a hot water supply system capable of optimizing the overall energy efficiency of a system including a heat pump type water heater and a gas water heater, for example, when hot water runs out.

The hot water supply system according to the first invention includes a hot water storage tank for storing hot water and a hot water storage tank.
A heat pump type heating means capable of supplying hot water to the hot water storage tank,
It is provided with an auxiliary heating means capable of heating hot water supplied from the hot water storage tank to the hot water supply terminal.
The heat pump independent operation in which the heat pump type heating means is operated independently, and the heat pump independent operation.
It is possible to perform an auxiliary heating operation in which the heat pump type heating means and the auxiliary heating means are operated at the same time.
The heat pump independent operation is performed when hot water is not discharged from the hot water supply terminal and the amount of hot water stored in the hot water storage tank is less than a predetermined amount.
The auxiliary heating operation is performed when hot water is discharged from the hot water supply terminal and the amount of hot water stored in the hot water storage tank becomes less than a predetermined amount.
When the outside air temperature is the same, the compressor frequency of the heat pump type heating means during the auxiliary heating operation is larger than the compressor frequency of the heat pump type heating means during the heat pump independent operation, and the auxiliary heating operation is performed. The heat pump efficiency of the heat pump type heating means at the time is lower than the heat pump efficiency of the heat pump type heating means when the heat pump is independently operated.

In this hot water supply system, for example, when the heat pump type heating means and the auxiliary heating means are operated at the same time to perform the boiling operation when the hot water runs out, the heat pump efficiency of the heat pump type heating means is lowered and the compressor frequency is increased. , The heating capacity as a heat pump type heating means increases. Therefore, the heating ratio of the heat pump type heating means in the entire hot water supply system increases, and the overall energy efficiency of the hot water supply system including the heat pump type heating means and the auxiliary heating means can be optimized.
Further, in this hot water supply system, when hot water is discharged from the hot water supply terminal and the amount of hot water stored in the hot water storage tank becomes less than the predetermined amount, the auxiliary heating operation is performed, so that even if the amount of hot water stored in the hot water storage tank becomes small. , You can continue to discharge hot water from the hot water supply terminal.

In the hot water supply system according to the second invention, in the first invention, when the outside air temperature is the same during the auxiliary heating operation, the compressor frequency of the heat pump type heating means during the auxiliary heating operation is the heat pump. Higher than the compressor frequency of the heat pump type heating means during independent operation, and the heat pump efficiency of the heat pump type heating means during the auxiliary heating operation is lower than the heat pump efficiency of the heat pump type heating means during the independent operation of the heat pump. After deriving the heating capacity of the heat pump type heating means, the heating capacity of the auxiliary heating means is derived based on the heating capacity of the heat pump type heating means that is insufficient. do.

In the above invention, the heating capacity of the heat pump type heating means during the auxiliary heating operation is larger than the heating capacity at which the COP is maximized at the outside air temperature at that time, and the primary energy efficiency of the heat pump type heating means is high. , It may be derived so as to be equal to or higher than the primary energy efficiency of the auxiliary heating means.

In this hot water supply system, the COP is larger than the maximum heating capacity, and the primary energy efficiency of the heat pump type heating means is derived so as to be equal to or higher than the primary energy efficiency of the auxiliary heating means. This prevents the primary energy efficiency of the heat pump type heating means from becoming lower than the primary energy efficiency of the auxiliary heating means, lowers the primary energy efficiency of the heat pump type heating means, and lowers the energy efficiency of the entire hot water supply system. Can be prevented from doing so.

As described above, according to the present invention, the following effects can be obtained.

In the first invention, for example, when the heat pump type heating means and the auxiliary heating means are simultaneously operated to perform the boiling operation when the hot water runs out, the heat pump efficiency of the heat pump type heating means is lowered and the compressor frequency is increased. Therefore, the heating capacity as a heat pump type heating means is increased. Therefore, the heating ratio of the heat pump type heating means in the entire hot water supply system increases, and the overall energy efficiency of the system including the heat pump type water heater and the gas water heater can be optimized.
Further, in this hot water supply system, when hot water is discharged from the hot water supply terminal and the amount of hot water stored in the hot water storage tank becomes less than the predetermined amount, the auxiliary heating operation is performed, so that even if the amount of hot water stored in the hot water storage tank becomes small. , You can continue to discharge hot water from the hot water supply terminal.

Further, the heat pump type heating means is derived so that the COP is larger than the maximum heating capacity and the primary energy efficiency of the heat pump type heating means is equal to or higher than the primary energy efficiency of the auxiliary heating means. It is possible to prevent the primary energy efficiency of the auxiliary heating means from becoming lower than the primary energy efficiency of the auxiliary heating means, and prevent the primary energy efficiency of the heat pump type heating means from becoming low and the energy efficiency of the entire hot water supply system from being lowered.

It is a block diagram of the hot water supply system of embodiment of this invention. It is a figure which shows the structure of the control part of the hot water supply system of FIG. It is a figure which shows the change of COP when the heating capacity of a heat pump part changes. It is a figure which shows the change of the primary energy efficiency when the heating capacity of a heat pump part changes. It is a flowchart explaining the operation of the hot water supply system of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration diagram of a hot water supply system according to an embodiment of the present invention. The hot water supply system 1 has a heat pump unit 2 and a water unit unit 3. The heat pump unit 2 includes a compressor 11, an outdoor heat exchanger 12, an expansion valve 13, a heat exchanger 16 for hot water supply, a fan 15, a refrigerant pipe 40, and a controller 20 (see FIG. 2). ing. The controller 20 is also used as the heat pump unit 2 and the water unit unit 3.

The heat pump unit 2 includes a refrigerant circuit 41 in which the refrigerant circulates in the refrigerant pipe 40 connecting the compressor 11, the outdoor heat exchanger 12, the expansion valve 13, and the hot water supply heat exchanger 16. In the refrigerant circuit 41, the refrigerant inlet of the hot water supply heat exchanger 16 is connected to the discharge side of the compressor 11, and one end of the outdoor heat exchanger 12 is connected to the suction side of the compressor 11. .. One end of the expansion valve 13 is connected to the other end of the outdoor heat exchanger 12, and the refrigerant outlet of the hot water supply heat exchanger 16 is connected to the other end of the expansion valve 13. The fan 15 is arranged so as to face the outdoor heat exchanger 12.

In the heating operation of the hot water supply system 1, as shown by the arrow in FIG. 1, the refrigerant discharged from the compressor 11 flows in order to the hot water supply heat exchanger 16, the expansion valve 13, and the outdoor heat exchanger 12, and the outdoor heat exchange occurs. A heating cycle (positive cycle) is formed in which the refrigerant that has passed through the vessel 12 returns to the compressor 11. That is, the hot water supply heat exchanger 16 functions as a condenser, and the outdoor heat exchanger 12 functions as an evaporator. In this heating operation, the hot water for hot water supply is heated by heat exchange between the refrigerant flowing from the discharge side of the compressor 11 and the hot water for hot water supply in the hot water supply heat exchanger 16.

The water unit unit 3 includes a pump 17, a hot water supply tank 5, a gas water heater 6, a hot water supply terminal 10, water pipes 45 and 46, a hot water outlet temperature sensor 22, and a controller 20. The water unit portion 3 includes a hot water circuit 48 in which hot water circulates in a water pipe 45 connecting the pump 17 and the hot water supply heat exchanger 16. In the hot water circuit 48, the discharge side of the pump 17 is connected to the hot water inlet of the hot water supply heat exchanger 16, and the suction side of the pump 17 is connected to one end of the hot water supply tank 5. The hot water outlet of the hot water supply heat exchanger 16 is connected to the other end of the hot water supply tank 5.

In the hot water circuit 48, hot water that exchanges heat with the refrigerant flowing through the hot water supply heat exchanger 16 circulates. Specifically, when the heating operation is executed, the hot water for hot water flowing out from the hot water supply tank 5 is supplied to the heat exchanger 16 for hot water supply by the pump 17, and the hot water heated by the heat exchanger 16 for hot water supply is supplied with hot water. Returned to tank 5. The gas water heater 6 connected to the hot water supply tank 5 by a water pipe 46 has a heater 6a and is connected to the hot water supply terminal 10. Therefore, the gas water heater 6 can heat the hot water for hot water supply supplied from the hot water supply tank 5 before it is supplied to the hot water supply terminal 10. The hot water supply terminal 10 makes the hot water in the hot water supply tank 5 available to the user.

The outside air temperature sensor 21 detects the outside air temperature and outputs it to the control unit 30. The hot water outlet temperature sensor 22 is arranged near the hot water outlet of the hot water supply heat exchanger 16 and detects the temperature of the hot water flowing out from the hot water supply heat exchanger 16 and outputs the temperature to the control unit 30. The outside air temperature sensor 21 and the hot water temperature sensor 22 may be any type as long as the detected temperature can be output to the control unit 30.

As described above, the hot water supply system 1 includes a heat pump unit 2 (heat pump type heating means) capable of supplying hot water to the hot water storage tank 5 and a gas water heater 6 (heat pump type heating means) capable of heating hot water supplied to the hot water supply terminal 10. It has an auxiliary heating means). Here, the hot water supply system 1 is capable of boiling up the hot water in the hot water storage tank 5 or the hot water supplied to the hot water supply terminal 10, and as the boiling operation, the heat pump alone operates the heat pump unit 2 independently. The operation and the auxiliary heating operation in which the heat pump unit 2 and the gas water heater 6 are operated at the same time are possible.

As shown in FIG. 2, the control unit 30 of the hot water supply system includes a hot water shortage determination unit 31, a COP curve storage unit 32, a COP curve calculation unit 33, an efficiency calculation unit 34, a capacity derivation unit 35, and boiling. It has a control unit 36. The input side of the control unit 30 is connected to a temperature sensor 5a attached to the upper side surface of the hot water supply tank 5, a controller 20, an outside air temperature sensor 21, and a hot water outlet temperature sensor 22. The output side of the control unit 30 is connected to the compressor 11, the heating unit 6a, and the pump 17.

The hot water shortage determination unit 31 determines whether or not the amount of hot water stored in the hot water supply tank 5 has decreased (the ratio of hot water in the hot water supply tank 5 has decreased) and the hot water has run out (whether or not it is necessary to perform boiling operation). To judge. In the present embodiment, when the temperature detected by the temperature sensor 5a attached to the upper side surface of the hot water supply tank 5 is lower than the hot water storage target temperature by a predetermined temperature or more, the hot water shortage determination unit 31 of the hot water supply tank 5 Assuming that the ratio decreases and the water runs out, it is judged that the boiling operation is necessary. The hot water discharge target temperature is input by operating the controller 20 by the user.

The COP curve storage unit 32 stores a plurality of COP curves, and the plurality of COP curves correspond to various outside air temperatures and hot water target temperatures, respectively. As shown in FIG. 3, the COP curve has a heating capacity (compressor frequency) on the horizontal axis and a COP on the vertical axis, and shows the heating capacity of the heat pump unit 2 and the COP at that heating capacity. As shown in FIG. 3, the COP of the heat pump unit 2 has a maximum value b in the heating capacity a1.

The COP curve calculation unit 33 calculates the COP curve based on the outside air temperature and the hot water target temperature at that time when the hot water discharge is started and the hot water shortage determination unit 31 determines that the boiling operation needs to be performed. do. In the present embodiment, since the COP curve storage unit 32 stores a plurality of COP curves, the COP curve calculation unit 33 can select the outside air temperature at that time from the COP curves stored in the COP curve storage unit 32. Acquire the COP curve based on the target temperature of hot water. The outside air temperature is the temperature detected by the outside air temperature sensor 21, and the hot water target temperature is the temperature input by the controller 20.

The efficiency calculation unit 34 calculates the primary energy efficiency of the heat pump unit 2 based on the COP curve acquired by the COP curve calculation unit 33. In the present embodiment, the efficiency calculation unit 34 calculates the primary energy efficiency by using the primary energy conversion coefficient 0.369 for each COP curve. Therefore, in the primary energy efficiency curve calculated based on the COP curve, as shown in FIG. 4, the horizontal axis is the heating capacity (compressor frequency) and the vertical axis is the primary energy efficiency, and the heating capacity of the heat pump unit 2 is set. And the primary energy efficiency at that heating capacity. As shown in FIG. 4, the curve of the primary energy efficiency calculated based on the COP curve has the maximum value c in the heating capacity a1. In FIG. 4, the primary energy efficiency of the gas water heater 6 is shown as d.

The capacity deriving unit 35 increases the heating capacity of the heat pump type water heater 2 so that the heating capacity maximizes the COP in the COP curve of FIG. 3 when the heat pump independent operation is performed in which the heat pump unit 2 is operated independently. Derived as a1.

On the other hand, in the capacity deriving unit 35, when the auxiliary heating operation for simultaneously operating the heat pump unit 2 and the gas water heater 6 is performed, the primary energy efficiency of the heat pump unit 2 is the same as the primary energy efficiency of the gas water heater 6. The heating capacity of the heat pump unit 2 is derived so as to be. Therefore, as shown in FIG. 4, the capacity deriving unit 35 determines that the primary energy efficiency of the heat pump unit 2 is the primary energy efficiency of the gas water heater 6 based on the primary energy efficiency curve calculated based on the COP curve. The heating capacity of the heat pump unit 2 is derived as a2 so as to be the same as d.

In this way, the capacity derivation unit 35 derives the heating capacity of the heat pump unit 2 as a1 when the heat pump unit 2 is operated independently when the outside air temperature is the same. , When the auxiliary heating operation for operating the heat pump unit 2 and the gas water heater 6 at the same time is performed, the heating capacity of the heat pump unit 2 is derived as a2. Therefore, in the capacity deriving unit 35, the compressor frequency of the heat pump unit 2 during the auxiliary heating operation is larger than the compressor frequency of the heat pump unit 2 during the heat pump independent operation, and the heat pump efficiency of the heat pump unit 2 during the auxiliary heating operation. However, the heating capacity of the heat pump unit 2 is derived so as to be lower than the heat pump efficiency of the heat pump unit 2 when the heat pump is independently operated.

Further, as described above, the capacity deriving unit 35 derives the heating capacity of the heat pump unit 2 during the auxiliary heating operation, and then, as the heating capacity of the boiling operation, the heating capacity of the heat pump unit 2 is insufficient. Based on the above, the heating capacity of the gas water heater 6 is derived.

The boiling control unit 36 controls the frequency of the compressor 11 and the rotation speed of the pump 17 during the heat pump independent operation and the auxiliary heating operation. Specifically, the boiling control unit 36 controls the frequency of the compressor 11 based on the heating capacity of the heat pump unit 2 derived by the capacity extraction unit 35, and the gas water heater 6 derived by the capacity extraction unit 35. The heating unit 6a of the gas water heater 6 is controlled based on the heating capacity to perform the boiling operation. Further, the boiling control unit 36 keeps the frequency of the compressor 11 constant and controls the rotation speed of the pump 17 so as to reach the hot water target temperature.

When the heat pump is independently operated, as described above, the capacity deriving unit 35 derives the heating capacity of the heat pump type water heater 2 as a1 so that the heating capacity maximizes the COP. Therefore, the frequency of the compressor 11 is controlled based on the heating capacity a1 until the hot water temperature detected by the hot water temperature sensor 22 reaches the target hot water temperature.

During the auxiliary heating operation, as described above, the capacity deriving unit 35 derives the heating capacity of the heat pump unit 2 as a2. Therefore, the frequency of the compressor 11 is controlled based on the heating capacity a2 until the hot water temperature detected by the hot water temperature sensor 22 reaches the target hot water temperature. After the hot water temperature detected by the hot water temperature sensor 22 reaches the target hot water temperature, the compressor 11 operates at a frequency (frequency based on the heating capacity a2) higher than the frequency (frequency based on the heating capacity a1) when the heat pump is independently operated. The pump 17 is controlled and the pump 17 is controlled at a frequency higher than the rotation speed of the pump 17 when the heat pump is operated independently. In this way, since the pump 17 is driven at a large rotation speed during the auxiliary heating operation, the flow rate of the hot water circulating in the water unit 3 increases, and while maintaining the hot water temperature constant, compared with the heat pump alone operation. The amount of hot water stored in the hot water supply tank 5 can be increased per unit time.

The operation of the hot water supply system of the present embodiment will be described with reference to FIG.

In step S1, it is determined whether or not the hot water from the hot water supply terminal 10 has started to be discharged. If it is determined in step S1 that the hot water from the hot water supply terminal 10 has started, the process proceeds to step S2 to start the hot water from the hot water supply terminal 10. In step S3, the amount of hot water stored in the hot water supply tank 5 is reduced, and it is determined whether or not the hot water has run out. If it is determined in step S3 that the hot water has run out, the process proceeds to step S4, and a COP curve is calculated based on the outside air temperature and the hot water target temperature at that time. Then, in step S5, the primary energy efficiency of the heat pump unit 2 is calculated based on the COP curve.

Here, if the hot water runs out while the hot water is being discharged from the hot water supply terminal 10, an auxiliary heating operation for simultaneously operating the heat pump unit 2 and the gas water heater 6 is performed. Therefore, in step S6, the heat pump unit The heating capacity of 2 is derived, and the heating capacity of the gas water heater 6 is derived. In step S7, the frequency of the compressor 11 is controlled based on the heating capacity of the heat pump unit 2 derived in this way, and the gas water heater 6 is based on the heating capacity of the gas water heater 6 derived by the capacity extraction unit 35. The heating unit 6a of the above is controlled to perform a boiling operation. After that, in step S8, it is determined whether or not the hot water from the hot water supply terminal 10 has been discharged. When it is determined in step 8 that the hot water from the hot water supply terminal 10 has been discharged, the hot water from the hot water supply terminal 10 is terminated.

<Characteristics of the hot water supply system of this embodiment>
In the hot water supply system of the present embodiment, when the heat pump unit 2 and the gas water heater 6 are operated at the same time to perform the boiling operation when the hot water runs out, the heat pump efficiency of the heat pump unit 2 is lowered and the compressor frequency is increased. Therefore, the heating capacity of the heat pump unit 2 increases. Therefore, the heating ratio of the heat pump unit 2 in the entire hot water supply system increases, and the overall energy efficiency of the hot water supply system 1 including the heat pump unit 2 and the gas water heater 6 can be optimized.

In the hot water supply system of the present embodiment, when hot water is discharged from the hot water supply terminal 10 and the amount of hot water stored in the hot water storage tank 5 becomes less than a predetermined amount, the auxiliary heating operation is performed, so that the amount of hot water stored in the hot water storage tank 5 is small. Even if it becomes, the hot water can be continuously discharged from the hot water supply terminal 10.

In the hot water supply system of the present embodiment, when the auxiliary heating operation in which the heat pump unit 2 and the gas water heater 6 are operated at the same time is performed, the heating capacity is larger than the maximum COP and the primary energy efficiency of the heat pump unit 2 is higher. It is derived so as to be equal to or higher than the primary energy efficiency of the gas water heater 6. As a result, the primary energy efficiency of the heat pump unit 2 is prevented from becoming lower than the primary energy efficiency of the gas water heater 6, the primary energy efficiency of the heat pump unit 2 is lowered, and the energy efficiency of the entire hot water supply system is lowered. Can be prevented.

Although the embodiments of the present invention have been described above with reference to the drawings, it should be considered that the specific configuration is not limited to these embodiments. The scope of the present invention is shown by the scope of claims rather than the description of the above-described embodiment, and further includes all modifications within the meaning and scope equivalent to the scope of claims.

In the above-described embodiment, the heat pump unit 2 has a heating capacity (a2) (compressor frequency corresponding to the heating capacity) during the auxiliary heating operation and the primary energy efficiency is the primary energy efficiency d of the gas water heater 6. The heating capacity was derived. However, the present invention is not limited to this, and when the outside air temperature is the same, the heating capacity of the heat pump unit 2 during the auxiliary heating operation (compressor frequency corresponding thereto) is the heating capacity (a1) (this) during the heat pump independent operation. The effect of the present invention can be obtained when the heat pump efficiency of the heat pump unit 2 during the auxiliary heating operation is lower than the heat pump efficiency of the heat pump unit 2 during the heat pump independent operation.

In the above-described embodiment, when hot water is discharged from the hot water supply terminal 10 and the amount of hot water stored in the hot water storage tank 5 becomes less than a predetermined amount, it is assumed that the hot water has run out, and the heat pump unit 2 and the gas water heater 6 are operated at the same time. Although the case where the operation is performed has been described, an auxiliary heating operation in which the heat pump unit 2 and the gas water heater 6 are operated at the same time may be performed on the assumption that the hot water has run out by another method.

In the above-described embodiment, the case where the hot water supply system has the gas water heater 6 as the auxiliary heating means has been described, but the auxiliary heating means is not limited to the gas water heater. Therefore, the hot water supply system may have other heating means such as an electric heater as an auxiliary heating means.

According to the present invention, when the heat pump type heating means and the auxiliary heating means are operated at the same time to perform the boiling operation, the energy efficiency can be improved by increasing the heating ratio of the heat pump type heating means.

2 Heat pump section (heat pump type heating means)
5 Hot water storage tank 6 Gas water heater (auxiliary heating means)

Claims (2)

A hot water storage tank for storing hot water and
A heat pump type heating means capable of supplying hot water to the hot water storage tank,
It is provided with an auxiliary heating means capable of heating hot water supplied from the hot water storage tank to the hot water supply terminal.
The heat pump independent operation in which the heat pump type heating means is operated independently, and the heat pump independent operation.
It is possible to perform an auxiliary heating operation in which the heat pump type heating means and the auxiliary heating means are operated at the same time.
The heat pump independent operation is performed when hot water is not discharged from the hot water supply terminal and the amount of hot water stored in the hot water storage tank is less than a predetermined amount.
The auxiliary heating operation is performed when hot water is discharged from the hot water supply terminal and the amount of hot water stored in the hot water storage tank becomes less than a predetermined amount.
When the outside air temperature is the same, the compressor frequency of the heat pump type heating means during the auxiliary heating operation is larger than the compressor frequency of the heat pump type heating means during the heat pump independent operation, and the auxiliary heating operation is performed. A hot water supply system characterized in that the heat pump efficiency of the heat pump type heating means at the time is lower than the heat pump efficiency of the heat pump type heating means when the heat pump is independently operated. When the outside air temperature is the same during the auxiliary heating operation, the compressor frequency of the heat pump type heating means during the auxiliary heating operation is higher than the compressor frequency of the heat pump type heating means during the heat pump independent operation. After deriving the heating capacity of the heat pump type heating means so that the heat pump efficiency of the heat pump type heating means during the auxiliary heating operation is lower than the heat pump efficiency of the heat pump type heating means during the heat pump independent operation. The hot water supply system according to claim 1, wherein the heating capacity of the auxiliary heating means is derived based on the heating capacity of the heat pump type heating means that is insufficient.

Images