JP4452051B2 - Heat pump water heater - Google Patents

Description

  The present invention relates to an instantaneous water heater type heat pump water heater capable of generating hot water using a heat pump cycle and discharging the generated hot water as it is without storing it in a hot water storage tank.

In a hot water supply apparatus that uses a heat pump cycle, frost formation occurs in the evaporator depending on the outside air temperature and operating conditions, and therefore, defrosting operation is performed by detecting frost formation.
The prior art heat pump water heater shown in Patent Document 1 is a hot water storage type heat pump water heater that includes a hot water storage tank and uses hot water previously stored in the hot water storage tank, and operates the heat pump cycle to store the hot water tank. When hot water is being stored, if frost formation is detected immediately before the completion of hot water storage and switching to defrosting operation, hot water storage completion is delayed.To prevent this, defrosting operation is required when hot water storage is not complete. Then, the remaining heating amount of water in the hot water storage tank is detected, and if the remaining heating amount is equal to or less than a predetermined amount, the request for the defrosting operation is masked for a predetermined time, and the hot water storage operation is prioritized.
That is, as shown in the flowchart of FIG. 3, hot water storage is started by starting the operation of the refrigerant circuit (step 11). Then, it is determined whether or not the hot water storage is completed (step 12). When the hot water storage is completed, a defrosting operation is performed in preparation for the next hot water storage operation (step 13), and then the hot water storage operation is terminated (step 14). ). On the other hand, if the hot water storage is not completed, it is determined whether or not there is a defrost request (frost formation) (step 15). When the defrosting operation is requested at this time, it is determined whether the remaining heating amount is equal to or less than a predetermined amount (step 16). If it is less than the predetermined amount, mask the request for defrosting operation for a predetermined time, enter the heating priority mode for preferentially storing hot water, start the timer and perform the heating priority mode for a predetermined time (step 48) Thereafter, a defrosting operation is performed (step 47).
JP 2001-255003 A

  However, the above-described conventional configuration is intended for a hot water storage type heat pump water heater, and in an instantaneous water heater type heat pump water heater that can discharge generated hot water without storing it in a hot water tank, When frost formation was detected during the hot water supply of hot water generated by operating and the defrosting operation was performed as it was, there was a problem that hot water shortage may occur.

  This invention solves such a conventional subject, and it aims at providing the heat pump hot-water supply apparatus which suppresses generation | occurrence | production of a hot-water supply in the instantaneous hot water type heat pump hot-water supply apparatus.

The heat pump hot water supply apparatus of the present invention according to claim 1 is a refrigerant circuit in which a compressor, a hot water supply heat exchanger, a decompressor, an evaporator are connected in an annular shape to flow a refrigerant, and the supplied water is used as the hot water supply heat exchanger. A hot water storage tank for storing hot water generated by heat exchange with the refrigerant, and mixing means for mixing the hot water stored in the hot water storage tank with the hot water generated in the hot water supply heat exchanger and directly supplied water A heat pump hot water supply apparatus comprising a hot water supply circuit for supplying hot water and a hot water supply control means for controlling a mixing ratio of the mixing means to obtain a predetermined hot water supply temperature and a hot water supply amount, wherein the hot water supply control means is a second of the evaporator. Frost detection means for detecting at least two of the first frost state and the second frost state, a defrost means for defrosting the evaporator when any of the frost states is detected, and the hot water storage Remaining hot water detection to detect the amount of hot water stored in the tank And having a stage, wherein when it is detected first frost condition, if the remaining hot water is a predetermined value or more is performed defrosting operation, when the remaining hot water is less than the predetermined value the second wear The defrosting operation is prohibited until the frost state is detected, and the defrosting operation is performed after detecting the second frosting state .
The invention of claim 2, wherein the heat pump water heater according to claim 1, when detecting the first frost condition, if the remaining hot water is less than the predetermined value, by the hot water supply control means The hot water supply amount is controlled to a predetermined value or less.
According to a third aspect of the present invention, in the heat pump hot water supply apparatus according to the first or second aspect , carbon dioxide is used as the refrigerant, and the high pressure side of the refrigerant circuit is operated in a supercritical pressure state. And

  The present invention can suppress the occurrence of hot water out by delaying the start of the defrosting operation when the amount of remaining hot water in the hot water tank is small even if frosting of the evaporator is detected during hot water supply. When the frosting state is detected, the evaporator is defrosted. Thereby, it is possible to perform the defrosting operation while maintaining the reliability of the compressor while suppressing the occurrence of running out of hot water.

In the heat pump hot water supply apparatus according to the first embodiment of the present invention, the hot water supply control means detects at least two ways of the first frost state and the second frost state of the evaporator, When such a frosting state is detected, there is a defrosting means for defrosting the evaporator, and a remaining hot water amount detecting means for detecting the remaining amount of hot water stored in the hot water tank. According to the present embodiment, by detecting at least two frosting states, a defrosting operation according to the frosting state can be performed, and the occurrence of hot water shortage can be finely suppressed. Further, when the first frost state is detected, the defrosting operation is performed when the remaining hot water amount is a predetermined value or more, and the defrosting is performed until the second frost state is detected when the remaining hot water amount is less than the predetermined value. The operation is prohibited, and the defrosting operation is performed after detecting the second frosting state. According to this embodiment, the defrosting operation can be performed while maintaining the reliability of the compressor while suppressing the occurrence of hot water shortage.
The second embodiment of the present invention is the heat pump hot water supply apparatus according to the first embodiment, when detecting the first frost formation condition, if the remaining hot water is less than the predetermined value, the hot water by the hot water supply control means The amount is controlled to a predetermined value or less. According to the present embodiment, the hot water supply capability of the heat pump is reduced due to frost formation on the evaporator, and hot water supply can be performed while suppressing the occurrence of hot water shortage even in a state where the amount of remaining hot water in the hot water storage tank is small.
In the heat pump water heater according to the first or second embodiment, the third embodiment of the present invention uses carbon dioxide as the refrigerant and operates the high pressure side of the refrigerant circuit in a supercritical pressure state. . According to this Embodiment, since hot water can be produced | generated, a hot water storage tank can be reduced in size.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a circuit configuration diagram showing a heat pump hot water supply apparatus according to an embodiment of the present invention.
The heat pump hot water supply apparatus of the present embodiment includes a refrigerant circuit, a hot water supply circuit, and hot water supply control means. The refrigerant circuit includes a compressor 1 that compresses the refrigerant, a heat exchanger for hot water supply that condenses the refrigerant and heats the water with the heat of condensation 2, a decompressor 3 that decompresses the refrigerant, and an evaporator 4 that evaporates the refrigerant A heat pump circuit formed by connection, a bypass circuit 5 for performing defrosting of the evaporator 4, and an on-off valve 6 provided in the bypass circuit 5 are configured. The refrigerant circuit is operated so that an appropriate amount of carbon dioxide is sealed as a refrigerant and the high pressure side is in a supercritical pressure state.
On the other hand, the hot water supply circuit, for example, a hot water storage tank 7 for storing hot water generated by exchanging water supplied from a water supply with a refrigerant in the hot water supply heat exchanger 2, and hot water stored in the hot water storage tank 7 and heat for hot water supply. A first mixing valve 8 that mixes the hot water generated in the exchanger 2 at a variable ratio; a second mixing valve 9 that mixes the hot water that has passed through the first mixing valve 8 and the directly supplied water at a variable ratio; A control valve 10 that controls the amount of water supply, check valves 11 and 12 that prevent back flow of water in the flow path, and a variable capacity water pump 13 and an on-off valve 14 for storing hot water in the hot water tank 7. Composed.
Further, the hot water supply control means receives the temperature sensors 15 to 17 for detecting the remaining hot water amount in the hot water storage tank 7, receives the temperature signals of these temperature sensors 15 to 17, determines the remaining hot water amount, and sends out the remaining hot water amount signal. The remaining hot water detection circuit 18, the flow rate sensor 19 for detecting the amount of hot water supply on the use side, the temperature sensor 20 for detecting the hot water supply temperature, and the hot water supply temperature detected by the temperature sensor 20 in response to the flow rate signal of the flow rate sensor 19 are predetermined. The hot water supply control circuit 21 that controls the mixing ratio of the first mixing valve 8 and the second mixing valve 9 so that the temperature becomes the temperature, the temperature sensor 22 that detects the temperature of the evaporator 4, and the temperature signal of the temperature sensor 22 The defrost control circuit 23 that receives the defrosting of the evaporator 4 and opens the on-off valve 6 of the bypass circuit 5 to defrost the evaporator 4, and the main control that controls the entire heat pump water heater according to the control flow Like device 24 Constructed.

Next, operation | movement of this heat pump hot-water supply apparatus is demonstrated. First, a hot water storage operation for storing hot water in the hot water tank 7 will be described.
During the hot water storage operation, the main controller 24 closes the flow paths of the first mixing valve 8 and the second mixing valve 9 of the hot water supply circuit, opens the open / close valve 14, and turns on the variable capacity water pump 13. Further, the compressor 1 of the refrigerant circuit is turned on. As a result, the lowermost water in the hot water tank 7 flows into the hot water supply heat exchanger 2 from the capacity variable water pump 13 and exchanges heat with the refrigerant to become hot hot water. Flow into. At this time, the temperature of the hot water flowing into the hot water tank 7 is detected by a temperature sensor or the like (not shown) so that the hot water flowing into the hot water tank 7 has a predetermined temperature, and the capacity of the capacity variable water pump 13 is changed. .
In this embodiment, if 80 ° C. hot water is generated, the water in the hot water storage tank 7 is replaced with 80 ° C. hot water from the upper part to the lower part. When the temperature sensor 15 disposed in the lower part reaches 80 ° C., the remaining hot water amount detection circuit 18 determines that the hot water storage is completed and sends a signal, and the main controller 24 turns off the variable capacity water pump 13 and the compressor 1. To do.

Next, the hot water supply operation will be described. When the use-side currant 25 or the like is opened, the flow rate sensor 19 detects the start of hot water supply, the hot water supply control circuit 21 sends a hot water supply start signal to the main controller 24, and the main controller 24 turns on the compressor 1. Then, the capacity variable water pump 13 is turned off and the on-off valve 14 is closed. The hot water supply control circuit 21 receives signals from the flow rate sensor 19 and the temperature sensor 20, and controls the opening degree of each flow path of the first mixing valve 8 and the second mixing valve 9 so that the hot water supply temperature becomes a predetermined temperature. To do.
Water flowing through the hot water supply circuit at this time is supplied from the water supply and passes through the control valve 10 to branch, one of which flows into the second mixing valve 9 through the check valve 11 and the other from the lower part of the hot water tank 7. It flows into the heat exchanger 2 for hot water supply through the check valve 12. Then, heat is exchanged with the refrigerant in the hot water supply heat exchanger 2 to obtain hot water of medium temperature (for example, about 45 ° C.) and flows into the first mixing valve 8. Further, hot water (for example, about 80 ° C.) stored in the hot water tank 7 is pushed by the water passing through the lower portion and flows into the first mixing valve 8. Accordingly, the first mixing valve 8 mixes hot and medium hot water at a variable ratio so that the temperature detected by the temperature sensor 20 becomes a predetermined temperature (for example, 42 ° C.), and further the second mixing valve 9. Then, the hot water control for obtaining a predetermined hot water supply temperature is performed by mixing the mixed hot water and low-temperature water directly supplied from the water supply at a variable ratio.

Next, control when the temperature sensor 22 detects frost formation on the evaporator 4 during the hot water supply operation will be described with reference to FIG. FIG. 2 is a flowchart showing hot water supply control of the heat pump hot water supply apparatus shown in FIG.
As shown in the figure, when the currant 25 is opened, the flow rate sensor 19 detects the flow rate and the hot water supply control circuit 21 determines the start of hot water supply (step 1), and the main controller 24 turns on the compressor 1. The hot water supply operation is started (step 2).
Here, the frost detection of the evaporator is determined to be the first frost state in which a predetermined amount of frost is formed when the temperature T1 detected by the temperature sensor 22 satisfies T1 ≦ Ta. In addition, when T1 ≦ Tb (Tb ≦ Ta), if the operation is further continued, the liquid refrigerant that could not be evaporated returns to the compressor, and the compressor may be damaged. Judged as frost. In addition, the structure which detects the three or more types of frost formation may be sufficient.
Then, when the temperature T1 detected by the temperature sensor 22 during the hot water supply operation becomes T1 ≦ Ta and the defrost control circuit 23 detects the first frosting state of the evaporator 4 (step 3), the hot water storage is then performed. The remaining hot water amount detection circuit 18 determines whether or not there is a remaining hot water amount equal to or larger than a predetermined amount in the tank 7 (step 4).
During the defrosting operation, medium temperature hot water cannot be generated by the hot water supply heat exchanger 2, and during that time, more hot water from the hot water tank 7 is used. Therefore, even in such a case, it is necessary to determine a sufficient amount of remaining hot water that does not run out by experimentation. In this embodiment, if the hot water temperature T2 in the hot water tank 7 detected by the temperature sensor 16 disposed in the intermediate part is 80 ° C. or higher (step 4), the hot water tank above the intermediate part has a temperature of 80 ° C. It is determined that the above hot water is stored and a sufficient amount of remaining hot water is secured, and the defrost control circuit 23 opens the on-off valve 6 to perform the defrosting operation (step 5).
On the other hand, if T2 is less than 80 ° C. (step 4), hot water may run out during the defrosting operation. Therefore, the first mixing is performed so that the hot water supply control circuit 21 reduces the hot water supply amount to a predetermined amount or less. The valve 8 and the second mixing valve 9 are controlled (step 6), and the hot water supply operation is continued. In addition, the structure which omits hot water supply amount control of step 6 may be sufficient.
When the temperature T1 detected by the temperature sensor 22 during the hot water supply operation becomes T1 ≦ Tb and the defrost control circuit 23 determines the second frosting state of the evaporator 4 (step 7), the defrost operation is performed. Transition (step 5). Moreover, frost detection (step 7) is repeated until the 2nd frost state of the evaporator 4 is detected. That is, the hot water supply operation is continued until the second frost state is detected, and the evaporator 4 is defrosted after the second frost state is detected.

  As described above, the heat pump hot water supply apparatus of the present embodiment is configured such that when the first frosting state is detected by the frost detection means and the remaining hot water amount detected by the remaining hot water amount detection means is greater than or equal to a predetermined value, the defrosting means uses the evaporator. When the amount of remaining hot water is less than a predetermined value, the defrosting of the evaporator is prohibited until the second frost state is detected, and the second frost state is detected by the frost detection means and then evaporated. To defrost the vessel. Thereby, defrosting operation can be performed while avoiding breakage of the compressor while suppressing occurrence of hot water shortage.

  In the above embodiment, the case where carbon dioxide is used as the refrigerant has been described, but other refrigerants such as R410A refrigerant and HC refrigerant may be used.

  As described above, the present invention is applied to a heat pump hot water supply device that generates hot water using a heat pump cycle, and discharges the generated hot water as it is without storing it in a hot water storage tank. For example, an instantaneous water heater for home use Suitable for

The circuit block diagram which shows the heat pump hot-water supply apparatus by one Example of this invention The flowchart which shows the hot_water | molten_metal supply control of the heat pump hot-water supply apparatus shown in FIG. The flowchart which shows the hot water supply control of the conventional heat pump hot water supply apparatus

DESCRIPTION OF SYMBOLS 1 Compressor 2 Heat exchanger for hot water supply 3 Decompressor 4 Evaporator 5 Bypass circuit 6,14 On-off valve 7 Hot water storage tank 8 First mixing valve 9 Second mixing valve 10 Control valve 11, 12 Check valve 13 Capacity variable water pump 15, 16, 17, 20, 22 Temperature sensor 18 Remaining hot water detection circuit 19 Flow rate sensor 21 Hot water supply control circuit 23 Defrost control circuit 24 Main controller 25 Curan

Claims (3)

A compressor, a hot water heat exchanger, a decompressor, and an evaporator are connected in a ring to store a refrigerant circuit that flows refrigerant, and hot water generated by heat exchange of the supplied water with the refrigerant in the hot water heat exchanger is stored. A hot water storage tank, a hot water supply circuit for supplying hot water with mixing means for mixing hot water stored in the hot water storage tank, hot water generated by the hot water supply heat exchanger and water supplied directly, and a predetermined hot water supply temperature and amount of hot water And a hot water supply device that controls a mixing ratio of the mixing means, wherein the hot water supply control means has a first frosting state and a second frosting state of the evaporator. Defrosting detection means for detecting at least two ways, defrosting means for defrosting the evaporator when any of the frosting states is detected, and remaining hot water amount for detecting the remaining amount of hot water stored in the hot water storage tank and has a detection means, detects the first frost conditions When the amount of remaining hot water is greater than or equal to a predetermined value, a defrosting operation is performed, and when the amount of remaining hot water is less than a predetermined value, the defrosting operation is prohibited until the second frosting state is detected, A heat pump hot-water supply device that performs a defrosting operation after detecting the frosting state of No. 2 . When detecting the first frost conditions, the remaining hot water If there is less than a predetermined value, according to claim 1, wherein the controller controls the hot water supply amount to a predetermined value or less by the hot water supply control means Heat pump water heater. The heat pump hot water supply apparatus according to claim 1 or 2 , wherein carbon dioxide is used as the refrigerant, and the high pressure side of the refrigerant circuit is operated in a supercritical pressure state.

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