JP6072670B2 - Heat pump hot water supply / heating system - Google Patents

Description

  The present invention relates to a heat pump hot water supply / heating system having a refrigerant circuit and a water circuit.

  2. Description of the Related Art Conventionally, in a heat pump hot water supply and heating system, there is a technique for detecting a heating capacity during operation and bringing it close to a necessary target heating capacity.

  As an example of using this technology, there is a heat pump type hot water supply device that detects an incoming water temperature with an incoming water thermistor, detects an outgoing hot water temperature with an outgoing hot water thermistor, and detects a heating capability during operation. The detected heating capacity is compared with the target heating capacity that is different for each boiling mode, and the operating frequency of the compressor is adjusted according to the difference so as to approach the target heating capacity (for example, Patent Documents). 1).

JP 2004-116891 A ([0036], [0039] and FIG. 1)

  The technology described in Patent Document 1 described above can accurately obtain the required target heating capacity in a hot water supply system with a known load, but the heating system in which the load and usage pattern of the heat radiating device are unknown. It is difficult to apply. This is because, in the technique described in Patent Document 1, the water circulation flow rate used for calculating the heating capacity is calculated from the output of the water circulation pump, and the accuracy of the calculation is unknown and fluctuates in the pressure loss of the water circuit. Not very expensive in a heating system. There are various types of heat dissipating devices installed in the heating system, and it is difficult to accurately grasp the flow rate of water in the heating system from the output of the water circulation pump.

  Generally, when a heat pump hot water supply / heating system is operated under a condition where the outside air temperature is low, the heat exchanger of the outdoor unit may be frosted and the heating capacity may be reduced. When the heating capacity is reduced due to frost formation, the performance test corresponding to the standards of each country is calculated by the integrated heating capacity including the defrosting operation, and the performance of the heat pump hot water supply / heating system is apparently evaluated to be low.

  Furthermore, depending on how the heat pump hot water supply / heating system is used, heating capacity or COP (Coefficient Of Performance) may be required, and at present, accurate heating capacity and COP are required unless a separate measuring instrument is installed. I can't control it.

The present invention has been made to solve the above-described problems, and a first object is to provide a heat pump that can accurately obtain a required target heating capacity even if the load state of the water circuit is unknown. A hot water supply and heating system is provided.
The second object is to provide a heat pump hot water supply and heating system that can accurately obtain a required COP even if the load state of the water circuit is unknown.

The heat pump hot water supply and heating system according to the present invention includes a compressor that circulates refrigerant in the refrigerant circuit, a water circulation pump that circulates water in the water circuit, and a refrigerant that circulates water circulated in the water circuit in the refrigerant circuit. A heat exchanger that converts heat into the heat exchanger, an incoming water temperature sensor that detects the temperature of water flowing into the heat exchanger, a hot water temperature sensor that detects the temperature of hot water flowing out of the heat exchanger, and the flow rate of water circulating in the water circuit. The flow rate sensor to detect and the control device to control the compressor, the control device calculates the current heating capacity based on the water temperature, hot water temperature and flow rate, the absolute value of the difference between the target heating capacity and the heating capacity When the absolute value is larger than the first constant, the absolute value is smaller than the first constant based on the operating frequency of the compressor and the ratio of the target heating capacity and the heating capacity. Calculate the target operating frequency and compress the compressor Operating frequency is controlled to be the target operating frequency.

  According to the present invention, the current heating capacity is calculated based on the water temperature, the hot water temperature, and the flow rate, and the current operating frequency of the compressor is controlled so that the calculated heating capacity reaches the target heating capacity. With this control, the current heating capacity can be accurately calculated even if the load state of the water circuit is unknown. For this reason, even the heating system in which the load of the heat radiating device fluctuates can be controlled to the required target heating capacity.

1 is a block diagram showing a schematic configuration of a heat pump hot water supply / heating system according to Embodiment 1. FIG. The flowchart which shows the control action of the compressor in the heat pump type hot-water supply heating system of FIG. The flowchart which shows the control action of the compressor in the heat pump type hot-water supply heating system which concerns on Embodiment 2. FIG.

Embodiment 1 FIG.
1 is a block diagram showing a schematic configuration of a heat pump hot water supply / heating system according to Embodiment 1. FIG.
The heat pump hot water supply and heating system in the present embodiment is composed of an outdoor unit 1 and an indoor unit 2 connected by a refrigerant pipe 3, and a cooling operation and a heating / hot water supply operation by a four-way valve 5 provided in the outdoor unit 1. It can be switched to either of these.

  The outdoor unit 1 includes a compressor 4, a four-way valve 5, an outdoor heat exchanger 6, an expansion valve 7, and the like. These components and an indoor heat exchanger 8 provided in the indoor unit 2 are sequentially connected by a refrigerant pipe 3. The refrigerant circuit is configured by being connected. For example, an electronic expansion valve is used as the expansion valve 7. The outdoor heat exchanger 6 is provided with a blower 9 that exchanges heat between the refrigerant flowing into the outdoor heat exchanger 6 and outdoor air.

  The indoor unit 2 includes an indoor heat exchanger 8, a heater built-in container 12, a three-way valve 13, a hot water storage tank 14, a water circulation pump 11, and the like, and these components are sequentially connected by a water pipe 10 to constitute a water circuit. . A heat radiating device 15 is connected to the water circuit. The heat radiating device 15 is installed indoors, and the water inflow side is connected to the three-way valve 13 through the water pipe 10, and the water outflow side is connected to the water circulation pump 11 through the water pipe 10. As the three-way valve 13, for example, an electric three-way valve is used.

  The water circuit is provided with a water flow rate sensor 16, an incoming water temperature sensor 17, and a hot water temperature sensor 18. The water flow rate sensor 16 is installed in the water pipe 10 on the water inflow side of the water circulation pump 11 and detects the flow rate of water circulated by the operation of the water circulation pump 11. The incoming water temperature sensor 17 is installed in the water pipe 10 on the water inflow side of the indoor heat exchanger 8 and detects the temperature of the water flowing into the indoor heat exchanger 8 by the operation of the water circulation pump 11. The hot water temperature sensor 18 is installed in the water pipe 10 on the water outflow side of the heater built-in container 12 and detects the temperature of the water flowing out from the heater built-in container 12. For example, a thermistor is used for the incoming water temperature sensor 17 and the outgoing water temperature sensor 18.

Here, the operation of the refrigerant circuit will be described. First, the refrigerant flow during the cooling operation will be described.
During the cooling operation, the high-temperature and high-pressure gas refrigerant discharged by the operation of the compressor 4 flows into the outdoor heat exchanger 6 through the four-way valve 5. The high-temperature and high-pressure gas refrigerant that has flowed into the outdoor heat exchanger 6 is heat-exchanged with the outdoor air blown by the blower 9 in the outdoor heat exchanger 6, that is, outside air, and becomes a low-temperature and high-pressure supercooled liquid refrigerant that serves as an expansion valve. Flows to 7. The low-temperature and high-pressure liquid refrigerant that has flowed to the expansion valve 7 is decompressed to become a low-temperature and low-pressure gas-liquid two-phase refrigerant, flows from the outdoor unit 1 to the indoor unit 2, and flows into the indoor heat exchanger 8. The gas-liquid two-phase refrigerant that has flowed into the indoor heat exchanger 8 is heat-exchanged with the circulating water that flows into the indoor heat exchanger 8 by the operation of the water circulation pump 11, and becomes high-temperature and low-pressure superheated gas refrigerant. The overheated gas refrigerant flows from the indoor unit 2 to the outdoor unit 1 and is sucked into the compressor 4 through the four-way valve 5.

Next, the operation of the refrigerant circuit during the heating operation will be described.
During the heating operation, the high-temperature and high-pressure gas refrigerant discharged by the operation of the compressor 4 flows from the outdoor unit 1 to the indoor unit 2 through the four-way valve 5 and flows into the indoor heat exchanger 8. The high-temperature and high-pressure gas refrigerant that has flowed into the indoor heat exchanger 8 is heat-exchanged with the circulating water that flows into the indoor heat exchanger 8 by the operation of the water circulation pump 11 to dissipate heat, and becomes a low-temperature and high-pressure supercooled liquid refrigerant. . Thereafter, the low-temperature and high-pressure liquid refrigerant flows from the indoor unit 2 to the outdoor unit 1, is decompressed by the expansion valve 7, becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant, and flows into the outdoor heat exchanger 6. The low-temperature and low-pressure refrigerant flowing into the outdoor heat exchanger 6 is heat-exchanged with the outdoor air blown by the blower 9, and becomes a high-temperature and low-pressure superheated gas refrigerant. Then, the superheated gas refrigerant is sucked into the compressor 4 from the outdoor heat exchanger 6 through the four-way valve 5.

Next, the operation of the water circuit by the indoor unit 2 will be described. Here, the flow of water during heating / hot water supply operation will be described.
The water discharged by the operation of the water circulation pump 11 flows into the indoor heat exchanger 8 and heat is exchanged with the high-temperature and high-pressure gas refrigerant from the outdoor unit 1 to become hot water. Thereafter, the hot water flows into the heater built-in container 12, is reheated as necessary, flows into the three-way valve 13, and flows into either the hot water storage tank 14 or the heat radiating device 15 based on the switching of the three-way valve 13. When hot water supply is selected by the user's remote control operation, the hot water flows into the hot water storage tank 14 to exchange heat with the water, and is drawn into the low temperature water by the water circulation pump 11. The warm water in the hot water storage tank 14 is used for hot water supply. Further, when heating is selected by the user's remote control operation, the hot water flows into the heat radiating device 15 to be dissipated and is drawn into the low temperature water by the water circulation pump 11. The heat radiated by the radiating device 15 is used for radiant heating.

  For example, during the heating operation, the control device 100 detects the water flow rate Q detected by the water flow rate sensor 16, the hot water temperature Wout detected by the hot water temperature sensor 18, and the incoming water temperature Win detected by the incoming water temperature sensor 17. Based on the above, the heating capacity during the current operation (hereinafter referred to as “current capacity CAP”) is calculated. This current capability CAP is obtained from the following equation (1).

CAP = Cp × Q × (Wout−Win) (1)
CAP: Current capacity Cp: Specific heat of water Q: Water flow rate Wout: Hot water temperature Win: Water temperature

In addition, the control device 100 includes, for example, a function formula F including two variables: a target heating capacity (hereinafter referred to as “target capacity CAPt”) set by remote control operation and a current capacity CAP, and a current operating frequency COM. The target operating frequency COMt of the compressor 4 is calculated using (x, y). This target operating frequency COMt is obtained from the following equation (2).
COMt = F (COM, CAPt / CAP) (2)
COMt: Target operating frequency F (x, y): Functional expression COM: Current operating frequency CAPt: Target capacity CAP: Current capacity

The calculation of the target operation frequency COMt will be described in detail when the control operation of the compressor 4 is described. However, the calculation is performed when the absolute value of the difference between the target capacity CAPt and the current capacity CAP is larger than the first constant α. Is called.
The function formula shown in formula (2) differs depending on the system configuration and is determined from the theoretical formula and test results.

Next, control of the compressor 4 is demonstrated based on the flowchart shown in FIG.
FIG. 2 is a flowchart showing the control operation of the compressor in the heat pump hot water supply and heating system of FIG.
For example, when the heating operation is selected by remote control operation, the control device 100 switches the four-way valve 5 so that the indoor heat exchanger 8 acts as a condenser and the outdoor heat exchanger 6 acts as an evaporator. And the control apparatus 100 starts the driving | operation of the compressor 4, circulates the refrigerant | coolant in a refrigerant circuit, starts the driving | operation of the water circulation pump 11, and circulates the water in a water circuit.

  Thereafter, when the heating target capacity CAPt is set by remote control operation (S1), the control device 100 sets the water flow rate Q detected by the water flow rate sensor 16 and the hot water temperature Wout detected by the hot water temperature sensor 18. The current capacity CAP is calculated from the incoming water temperature Win detected by the incoming water temperature sensor 17 and the specific heat Cp of water (S2).

  Then, the control device 100 compares the absolute value of the difference between the target capability CAPt and the current capability CAP with the first constant α (S3). When the absolute value is smaller than the first constant α, the control device 100 proceeds to S4, but when the absolute value is larger than the first constant α, the current operating frequency COM, the target capacity CAPt, and the current capacity CAP The target operating frequency COMt is calculated using a function formula F (x, y) including two variables based on the ratio (S5).

  The control device 100 controls the compressor 4 so that the current operation frequency COM of the compressor 4 becomes the calculated target operation frequency COMt. The control device 100 calculates the current capacity CAP again from the water flow rate Q, the hot water temperature Wout and the incoming water temperature Win, and the specific heat Cp of water, which are changed by this control (S2). Then, the control device 100 compares the absolute value of the difference between the target capability CAPt and the current capability CAP with the first constant α (S3).

  When the absolute value is larger than the first constant α, the control device 100 repeatedly performs the above-described operation (S3, S5, S2). When the absolute value becomes smaller than the first constant α due to the repetition of the operation, the control device 100 regards that the operating frequency COM of the compressor 4 has reached the target operating frequency COMt and ends (S4). That is, it is assumed that the current capability CAP has reached the target capability CAPt, and this state is maintained.

  As described above, in the first embodiment, the operation frequency COM of the compressor 4 is changed until the current capacity CAP calculated based on the water flow rate Q, the tapping temperature Wout and the incoming water temperature Win reaches the target capacity CAPt, When the absolute value of the difference between the target capacity CAPt and the current capacity CAP becomes smaller than the first constant α, it is considered that the operating frequency COM of the compressor 4 has reached the target operating frequency COMt. With this control, the current capacity CAP can be accurately calculated even if the load state of the water circuit is unknown. For this reason, even the heating system in which the load of the heat radiating device 15 fluctuates can be controlled to the required target capacity CAPt.

  Moreover, even when the heat exchanger of the outdoor unit is frosted, the accurate current capacity CAP can be calculated, so that the target capacity CAPt can be maintained and the capacity request from the user can be met. In addition, it is advantageous in a test corresponding to the standard.

  In the first embodiment, the present invention is applied to the frequency control of the compressor 4, but can also be applied to the rotational speed control of the blower 9 and the opening degree control of the expansion valve 7. In this case, the target rotational speed of the blower 9 and the target opening degree of the expansion valve 7 are calculated using a function expression including two variables, ie, a current value to be controlled and a ratio between the target capacity and the current capacity. By expanding the application range in this way, the current capability CAP can be made to reach the target capability CAPt with higher accuracy. In addition, control that improves COP (Coefficient Of Performance) with the same ability is also possible.

Embodiment 2. FIG.
FIG. 3 is a flowchart showing the control operation of the compressor in the heat pump hot water supply and heating system according to the second embodiment. In addition, the heat pump hot water supply and heating system according to Embodiment 2 is the same as that of Embodiment 1 shown in FIG.
In the second embodiment, the operating frequency COM of the compressor 4 is changed until the current COP reaches the target COPt, and the absolute value of the difference between the target COPt and the current COP becomes smaller than the second constant β. The operation frequency COM of the compressor 4 is regarded as reaching the target operation frequency COMt.

The control device 100 in the present embodiment uses, for example, a functional expression G (x, y) including two variables, a target COP and a ratio of the current COP set in accordance with the heating operation and the current operating frequency COM. The target operation frequency COMt of the compressor 4 is calculated. This target operating frequency COMt is obtained from the following equation (3).
COMt = G (COM, COPt / COP) (3)
COMt: target operation frequency G (x, y): function expression COM: current operation frequency COPt: target COP
COP: Current COP

The calculation of the target operation frequency COMt will be described in detail when the control operation of the compressor 4 is described, but is performed when the absolute value of the difference between the target COP and the current COP is larger than the second constant β.
Note that the function equation shown in equation (3) varies depending on the system configuration and is determined from the theoretical equation and test results.

Further, the control device 100 can calculate the input power INP by adding the input power (calculated from the input voltage and input current) to the compressor 4 and the input power to the heater of the heater built-in container 12. Therefore, COP (Coefficient Of Performance) is calculated from the current capability CAP and the input power INP. The COP is obtained from the following equation (4).
COP = CAP / INP (4)
COP: Coefficient of performance CAP: Current capacity INP: Input power

  In the present embodiment, when the heating operation is selected, for example, by a remote control operation, the control device 100 operates as described above, with the indoor heat exchanger 8 acting as a condenser and the outdoor heat exchanger 6 acting as an evaporator. Thus, the four-way valve 5 is switched. And the control apparatus 100 starts the driving | operation of the compressor 4, circulates the refrigerant | coolant in a refrigerant circuit, starts the driving | operation of the water circulation pump 11, and circulates the water in a water circuit.

  Thereafter, the control device 100 sets a target COP according to, for example, the heating operation (S11), the water flow rate Q detected by the water flow rate sensor 16, the hot water temperature Wout detected by the hot water temperature sensor 18, and the incoming water temperature. The current capacity CAP is calculated from the incoming water temperature Win detected by the sensor 17 and the specific heat Cp of water. Then, the control device 100 calculates the input power INP by adding the input power to the compressor 4 and the input power to the heater of the heater built-in container 12, and based on the calculated current capability CAP and the input power INP, COP is calculated (S12).

  The control device 100 compares the absolute value of the difference between the target COPt and the current COP with the second constant β (S13). When the absolute value is smaller than the second constant β, the control device 100 proceeds to S14. However, when the absolute value is larger than the second constant β, the current operating frequency COM and the ratio between the target COPt and the current COP The target operating frequency COMt is calculated using the functional expression G (x, y) including the two variables according to (S15).

  The control device 100 controls the compressor 4 so that the current operation frequency COM of the compressor 4 becomes the calculated target operation frequency COMt. The control device 100 calculates the current capacity CAP again from the water flow rate Q, the tapping temperature Wout and the incoming water temperature Win, and the specific heat Cp of water, which are changed by this control. Further, the control device 100 calculates the input power INP, and calculates the current COP again from the calculated current capability CAP and the input power INP (S12). Then, the control device 100 compares the absolute value of the difference between the target COPt and the current COP with the second constant β (S13).

  When the absolute value is larger than the second constant β, the control device 100 repeatedly performs the above-described operation (S13, S15, S12). When the absolute value becomes smaller than the second constant β due to the repetition of the operation, the control device 100 regards that the operation frequency COM of the compressor 4 has reached the target operation frequency COMt and ends (S14). That is, it is assumed that the current COP has reached the target COPt, and this state is maintained.

  As described above, in the second embodiment, the operating frequency COM of the compressor 4 is changed until the current COP reaches the target COPt, and the absolute value of the difference between the target COPt and the current COP is smaller than the second constant β. When this happens, it is considered that the operating frequency COM of the compressor 4 has reached the target operating frequency COMt. With this control, the current COP can be accurately calculated even if the load state of the water circuit is unknown. For this reason, even the heating system in which the load of the heat radiating device 15 fluctuates can be controlled to the required target COPt.

  Moreover, since control according to the required target COP is possible, a heat pump hot water supply / heating system with high energy saving effect can be provided.

  In the second embodiment, the present invention is applied to the frequency control of the compressor 4, but can also be applied to the rotational speed control of the blower 9 and the opening degree control of the expansion valve 7. In this case, the target rotational speed of the blower 9 and the target opening degree of the expansion valve 7 are calculated using a function expression including two variables, ie, a current value to be controlled and a ratio between the target capacity and the current capacity. By expanding the application range in this way, the current COP can be reached to the target COP with higher accuracy. Further, it is possible to perform control for improving the performance even with the same COP.

  Furthermore, if the above method is applied, not only the target COP is approached, but also the operating frequency of the compressor 4, the rotational speed of the blower 9, and the opening of the expansion valve 7 are optimized so as to search for a point where the COP becomes maximum. It is also possible to make it.

  In the first and second embodiments, the heat pump hot water supply / heating system has been described as an example. However, the present invention is not limited to this, and the present invention can be used for any other equipment. For example, the present invention can be applied to equipment such as a water heater and a chiller.

  DESCRIPTION OF SYMBOLS 1 Outdoor unit, 2 Indoor unit, 3 Refrigerant piping, 4 Compressor, 5 Four way valve, 6 Outdoor heat exchanger, 7 Expansion valve, 8 Indoor heat exchanger, 9 Blower, 10 Water piping, 11 Water circulation pump, 12 Built-in heater Container, 13 Three-way valve, 14 Hot water storage tank, 15 Heat dissipating device, 16 Water flow rate sensor, 17 Incoming water temperature sensor, 18 Hot water temperature sensor, 100 Control device.

Claims (2)

A compressor for circulating the refrigerant in the refrigerant circuit;
A water circulation pump for circulating the water in the water circuit;
A heat exchanger for heat-converting water circulating in the water circuit with refrigerant circulating in the refrigerant circuit;
An incoming water temperature sensor for detecting the temperature of water flowing into the heat exchanger;
A hot water temperature sensor for detecting the temperature of hot water flowing out of the heat exchanger;
A flow sensor for detecting a flow rate of water circulating in the water circuit;
A control device for controlling the compressor,
The control device calculates a current heating capacity based on the water temperature, the hot water temperature and the flow rate, compares the absolute value of the difference between the target heating capacity and the heating capacity with a first constant, and the absolute value is When larger than the first constant, based on the operating frequency of the compressor and the ratio of the target heating capacity and the heating capacity, the target operating frequency where the absolute value is smaller than the first constant is calculated, A heat pump hot water supply and heating system, wherein the operation frequency of the compressor is controlled to be the target operation frequency . A compressor for circulating the refrigerant in the refrigerant circuit;
A water circulation pump for circulating the water in the water circuit;
A heat exchanger that thermally converts water circulating in the water circuit with a refrigerant circulating in the refrigerant circuit; an incoming water temperature sensor that detects a water temperature flowing into the heat exchanger;
A hot water temperature sensor for detecting the temperature of hot water flowing out of the heat exchanger;
A flow sensor for detecting a flow rate of water circulating in the water circuit;
A control device for controlling the compressor,
The control device calculates a COP based on the heating capacity calculated based on the water temperature, the hot water temperature and the flow rate and the input power, and compares the absolute value of the difference between the target COP and the COP with a second constant. When the absolute value is larger than the second constant, the target operating frequency where the absolute value is smaller than the second constant is calculated based on the operating frequency of the compressor and the ratio of the target COP to the COP. heat Toponpu type hot-water supply heating system, and operating frequency of the compressor and controls so that the target operating frequency.

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