JP5353328B2 - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump type water heater capable of executing a defrosting operation according to necessity and suppressing running-out of hot water due to the defrosting operation. <P>SOLUTION: This water heater 11 includes a storage section for storing a plurality of divided time zones of one day including a first time zone, and a second time zone when the usage of water is more than the first time zone, and further storing a first reference value, and a second reference value set to have a condition of easy frost formation in comparison with the first reference value, as the reference values. A control section 33 determines necessity of the defrosting operation on the basis of the first reference value when the time zone is the first time zone, and determines the necessity of the defrosting operation on the basis of the second reference value when the time zone is the second time zone. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a heat pump type water heater.

  Generally, a heat pump type water heater is composed of a refrigerant circuit in which a compressor, a water heat exchanger, an expansion valve and an air heat exchanger are connected in this order by piping, a tank in which water is stored, and the water in this tank is converted into a water heat exchanger. And a hot water storage circuit having a hot water discharge pipe for returning water heated by the water heat exchanger to the tank. This heat pump type hot water heater has a problem that the air heat exchanger is frosted in winter.

  Therefore, Patent Document 1 discloses a heat pump type water heater that performs a defrosting operation for removing frost from the air heat exchanger based on a detection value of a temperature sensor that detects an outlet temperature of the air heat exchanger. ing.

JP 2003-222396 A

  In the technique described in Patent Document 1, the defrosting operation is started when the value detected by the temperature sensor decreases to a certain value (about −5 ° C.) (see Paragraph No. 0021 of Patent Document 1). Therefore, even if the amount of hot water that can be used in the tank is small, the defrosting operation is started when the detected value decreases to a certain value. For this reason, for example, when the defrosting operation is started in a time zone in which hot water is used, there is a possibility that hot water runs out.

  Therefore, the present invention has been made in view of such a point, and the object of the present invention is to suppress the occurrence of running out of hot water due to the defrosting operation while performing the defrosting operation as necessary. It is in providing the heat pump type hot water heater which can be performed.

The heat pump type water heater of the present invention has a compressor (19), a water heat exchanger (21), a pressure reducing mechanism (23), and an air heat exchanger (25), and a refrigerant circuit in which the refrigerant circulates sequentially. (13), a hot water storage circuit (17) having a small tank (15) having a capacity of 200 L or less in which water is stored, and capable of heating the water by the water heat exchanger (21), and the air heat exchanger Control means (33) for determining the necessity of a defrosting operation for defrosting the air heat exchanger (25) based on a reference value based on a physical quantity capable of determining the frosting state on (25). Yes. The heat pump water heater is stored in a manner divided into a plurality of time zones including a first time zone and a second time zone in which the amount of water used is greater than the first time zone. The apparatus further includes a storage unit that stores a first reference value as a value and a second reference value that is set to a condition in which frost formation is easier than the first reference value. When the time zone is the first time zone, the control means (33) performs the defrosting operation based on the first reference value regardless of the amount of remaining hot water stored in the tank (15) . Determining whether or not the defrosting operation is necessary based on the second reference value regardless of the amount of remaining hot water when the time zone is the second time zone . The timing of the defrosting operation is delayed by making it more difficult to perform the defrosting operation than when it is in one hour .

  In this configuration, the control means (33) determines whether or not the defrosting operation is necessary based on the first reference value when the time zone is the first time zone, and the time zone is more water than the first time zone. Whether or not the defrosting operation is necessary is determined based on the second reference value that is less likely to be required to be the defrosting operation than the first reference value when the usage amount is the second time zone. That is, in the second time zone when the amount of water used is high and the risk of running out of hot water increases, it is difficult to perform the defrosting operation by tightening the criteria for determining the necessity of the defrosting operation, while determining the frosting state. When the physical quantity to be reached reaches the second reference value and the necessity for defrosting further increases, defrosting is prioritized and the defrosting operation is executed. Thus, in this structure, while performing a defrost operation as needed, it can suppress that the hot water shortage resulting from a defrost operation arises.

  In the present invention, it is preferable that the reference value is a temperature of the air heat exchanger (25), and the second reference value is set to a value smaller than the first reference value.

  In this configuration, the reference value is the temperature of the air heat exchanger (25), and the second reference value is set to a value smaller than the first reference value. The temperature of the air heat exchanger (25) is easy to measure and is highly related to the frosting state.

In the present invention, the tank (15) is Ru small tank der within the capacity 200L. In such a water heater, for example, even when the entire amount in the tank (15) is heated at midnight using late-night power, additional boiling is performed at other times as the amount of hot water decreases. It is likely to need to be done. Therefore, when additional boiling is required during a time period when the amount of water used is large, it is difficult to perform the defrosting operation as described above. Can be effectively suppressed. Moreover, by making it difficult to perform the defrosting operation as described above and delaying the time of the defrosting operation from the usual time, some frost formation occurs in the air heat exchanger (25), and the water heat exchanger (21) Even if the heating capacity is slightly reduced, in the case of small tanks, the energy required for one boiling is less than in the case of other large tanks, so the time required for boiling should be kept small. Can do. Moreover, the installation area and installation height which install a heat pump type hot water heater can be made small by using a small tank.

  As described above, according to the present invention, it is possible to suppress the occurrence of running out of hot water due to the defrosting operation while performing the defrosting operation as necessary.

It is a lineblock diagram showing the heat pump type water heater concerning one embodiment of the present invention. It is a flowchart which shows the example 1 of control of the heat pump type water heater of FIG. It is a flowchart which shows the example 2 of control of the heat pump type water heater of FIG.

  Hereinafter, a heat pump type water heater according to an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the heat pump type water heater 11 according to the present embodiment boils low temperature water by heat exchange between a refrigerant circuit 13 that circulates refrigerant and the refrigerant in the refrigerant circuit 13, and supplies high-temperature water to a tank 15. And a hot water storage circuit 17 for storing hot water.

  The refrigerant circuit 13 blows air toward the compressor 19, the water heat exchanger 21, the electric expansion valve (decompression mechanism) 23, the air heat exchanger 25, a pipe connecting them, and the air heat exchanger 25. And a fan 43. In the present embodiment, carbon dioxide is used as the refrigerant circulating in the refrigerant circuit 13. This carbon dioxide is compressed to a critical pressure or higher by the compressor 19. The refrigerant exchanges heat with water circulating in the hot water storage circuit 17 in the water heat exchanger 21 to heat the water, and exchanges heat with the outside air in the air heat exchanger 25 to absorb heat from the outside air.

  The refrigerant circuit 13 is provided with a liquid gas heat exchanger 63 that performs heat exchange between the high-pressure refrigerant that has flowed out of the water heat exchanger 21 and the low-pressure refrigerant that has flowed out of the air heat exchanger 25, and therefore enters the compressor 19. The refrigerant can be overheated. Thereby, the wet compression of the compressor 19 can be suppressed.

  The hot water storage circuit 17 supplies the tank 15 with water heated by heat exchange between the tank 15 in which water is stored, a water inlet pipe 27 that sends water from the tank 15 to the water heat exchanger 21, and the water heat exchanger 21. A hot water supply pipe 29 to be returned and a pump 31 for circulating water in the hot water storage circuit 17 are provided.

  The tank 15 includes a hot water supply pipe 35 for taking out the stored hot water from the upper part of the tank 15 and supplying hot water to a bathtub or the like, and a water supply pipe 37 for supplying low temperature water such as tap water to the bottom of the tank 15. I have. The capacity of the tank 15 of this embodiment is a small tank of 200 liters or less.

  The water heater 11 includes an unillustrated memory (storage unit) for storing various data used for controlling the hot water heater 11 and an unillustrated clock function for knowing the time.

  The refrigerant circuit 13 includes a temperature sensor 57 that detects the temperature of the air heat exchanger 25 and a temperature sensor 59 that detects the discharge temperature of the compressor 19. The temperature sensor 57 is attached to a pipe through which the refrigerant flows in the air heat exchanger 25. Is provided.

  The hot water storage circuit 17 is attached to a water inlet pipe 27 on the upstream side of the water heat exchanger 21 and detects a temperature of water flowing into the water heat exchanger 21, and a downstream side of the water heat exchanger 21. A temperature sensor 41 that is attached to the hot water supply pipe 29 and detects the temperature of the water heated by the water heat exchanger 21 is provided.

  The tank 15 is attached to the upper part of the tank 15 to detect the temperature of the water in the upper part of the tank 15, and is attached to the central part to detect the temperature of the water in the central part of the tank 15. And a temperature sensor 55 that is attached to the lower part and detects the temperature of water in the lower part of the tank 15. By these temperature sensors 51, 53, 55, the amount of remaining hot water in the tank 15 is obtained. As each temperature sensor described above, for example, a thermistor can be used.

  The water heater 11 includes a control unit (control means) 33 including a microcomputer and an input / output circuit. The control unit 33 controls the refrigerant circuit 13 and the hot water storage circuit 17 based on the data from each temperature sensor described above.

  The control unit 33 drives the compressor 19 of the refrigerant circuit 13 to adjust the opening degree of the electric expansion valve 23 and drives the pump 31 of the hot water storage circuit 17. Thereby, the low temperature water in the tank 15 is sent to the water heat exchanger 21 through the water inlet pipe 27 from the water outlet provided at the bottom of the tank 15, and is heated in the water heat exchanger 21. The heated high-temperature water is returned into the tank 15 from the water inlet provided in the upper part of the tank 15 through the hot water supply pipe 29. As a result, in the tank 15 during the boiling operation, hot water is stored in the upper part, and the temperature of the water is lowered toward the lower part.

  The amount of hot water in the tank 15 is the amount of high-temperature water that can be used by the user, and can be obtained from the temperature and amount of water in the tank 15. In this embodiment, since the tank 15 is provided with the three temperature sensors 51, 53, 55, the temperature of the temperature sensor 51, 53, 55 is determined based on the height at which the temperature sensors 51, 53, 55 are attached and their detection data. It is possible to grasp how much water is present in the tank 15.

  The control unit 33 also controls a defrosting operation for defrosting the air heat exchanger 25. In the defrosting operation in the present embodiment, the controller 33 determines whether or not the defrosting operation is necessary, for example, as in the following control example, based on a reference value based on a physical quantity that can determine the frosting state on the air heat exchanger 25. Judging.

<Control example 1>
Next, a control example 1 of the water heater 11 will be described. FIG. 2 is a flowchart showing a control example 1 of the water heater 11.

  In this control example 1, the case where the control is performed by dividing one day into three time zones of a day time (first time zone), a living time (second time zone), and a night time (third time zone). An example will be described. Daytime is 10 to 17 o'clock, living time is 7 to 10 o'clock and 17 to 23 o'clock, and nighttime is 23 to 7 o'clock. Among these time zones, the living time (second time zone) generally uses more water than the day time (first time zone) and night time (third time zone).

  In this control example 1, the temperature of the air heat exchanger 25 detected by the temperature sensor 57 is used as a physical quantity that can determine the frosting state on the air heat exchanger 25. The control unit 33 determines whether the defrosting operation is necessary based on the first reference value (for example, −10 ° C.) when the time zone is the first time zone and the third time zone, and the time zone is the second time. When it is a belt, the necessity of the defrosting operation is determined based on the second reference value (for example, −13 ° C.). The defrosting operation is executed when the temperature of the air heat exchanger 25 becomes lower than the reference value.

  The memory of the water heater 11 stores the above three time zones, the first reference value, and the second reference value. These data may be set in advance before shipment of the product, may be set by a service person at the installation site, or may be set by the user as needed.

  As shown in FIG. 2, when the boiling operation of the water heater 11 is started, in step S1, the control unit 33 determines whether or not a predetermined boiling end condition is satisfied. The boiling end condition can be based on, for example, the amount of remaining hot water in the tank 15. For example, the control unit 33 determines that the boiling termination condition is satisfied when the temperature of the water detected by the temperature sensor 55 located at the lowermost portion is equal to or higher than a set temperature (for example, 85 ° C.). The controller 33 ends the boiling operation when the boiling end condition is satisfied, and proceeds to step S2 when the boiling end condition is not satisfied.

  In step S2, the control unit 33 determines which time zone the current time is in based on the data from the clock function. When the time (current time) at that time is in the first time zone or the third time zone, that is, when the amount of water used is relatively small in one day, the control unit 33 performs the step Proceed to S3. On the other hand, if the current time is in the second time zone, that is, if the amount of water used in the day is greater than the other time zones, the control unit 33 proceeds to step S4.

In step S3, since the current time is the first time zone or the third time zone, the control unit 33 sets a reference value (t _din ) that serves as a criterion for determining whether or not to enter the defrosting operation to the first reference value. Set to (t _din0 ) (for example, set to −10 ° C.) and proceed to step S5. In the first time zone or the third time zone where the amount of water used is less than that in the second time zone, even if the boiling operation is temporarily interrupted by entering the defrosting operation, there is a possibility that hot water will run out. Low compared to the case of the second time zone.

On the other hand, in step S4, since the current time is in the second time zone, the control unit 33 sets a reference value (t _din (° C.)) that serves as a criterion for determining whether or not to enter the defrosting operation to the second reference value. _Set (t _{din0 −Δt} (° C.)) (for example, set to −13 ° C.) and proceed to step S5. The second reference value is set to a temperature that is lower by Δt ° C. (3 ° C. in the present control example 1) than the first reference value. That is, the second reference value is a temperature at which frost formation is easier than the first reference value.

In step S5, the control unit 33 determines whether or not the temperature (t _e (° C.)) of the air heat exchanger is lower than the reference value (t _din (° C.)) set in step S3 or step S4. . When the temperature (t _e (° C.)) of the air heat exchanger is lower than the reference value (t _din (° C.)), the control unit 33 proceeds to step S6, and the temperature of the air heat exchanger (t _e (° C.) )) Is greater than or equal to the reference value (t _din (° C.)), the process returns to step S1 and the above control is repeated.

  In step S6, the control unit 33 starts the defrosting operation and proceeds to step S7. In the defrosting operation, the compressor 19 is driven in the refrigerant circuit 13, and the opening degree of the electric expansion valve 23 is made larger (for example, fully opened) than in the boiling operation. Thereby, since the refrigerant | coolant discharged from the compressor 19 reaches | attains the air heat exchanger 25, without a temperature fall largely, the defrost of the air heat exchanger 25 can be performed. During the defrosting operation, the pump 31 is stopped in the hot water storage circuit 17 to temporarily interrupt the boiling operation.

  In step S7, the control unit 33 determines whether or not a defrosting operation end condition is satisfied. The defrosting operation end condition can be based on the temperature of the air heat exchanger 25, for example. Specifically, for example, when the detection value of the temperature sensor 57 provided in the air heat exchanger 25 reaches a set value (for example, 5 ° C.), it is determined that the defrosting operation end condition is satisfied. When the defrosting operation end condition is not satisfied, the control unit 33 repeatedly determines whether or not the defrosting operation end condition is satisfied. When the defrosting operation end condition is satisfied, the control unit 33 proceeds to step S8. .

  In step S8, the control part 33 complete | finishes a defrost operation, returns to step S1, and repeats the said control.

  By performing the control as described above, it is possible to operate so as to end the predetermined boiling operation before entering the defrosting operation while delaying the entry to the defrosting operation as much as possible. That is, in the flowchart of FIG. 2, in the conventional control in which the reference value is only the first reference value, for example, the temperature of the air heat exchanger 25 falls below the first reference value and enters the defrosting operation. However, in the present control example 1, the reference value is set to the second reference value during the second time zone, so that it is difficult to enter the defrosting operation. That is, in the present control example 1, in the second time zone, it is more difficult to proceed from step S5 to step S6 than in the past, so the control flow of steps S1, S2, S4, S5, and S1 is executed. The heating operation can be continued for as long as possible during the operation (repeating), and in some cases, the operation to end the heating operation of the tank 15 can be performed without executing the defrosting operation. Become.

  As described above, in the above embodiment, the water heater 11 is divided into a plurality of time zones in which one day includes the first time zone and the second time zone in which the amount of water used is larger than the first time zone. And a storage unit in which a first reference value and a second reference value set to a condition where frost formation is easier than the first reference value are stored as the reference value. The control unit 33 determines whether the defrosting operation is necessary based on the first reference value when the time zone is the first time zone, and based on the second reference value when the time zone is the second time zone. To determine the necessity of defrosting operation. That is, in the second time zone in which the amount of water used is high and the risk of running out of hot water increases, it is difficult to perform the defrosting operation by tightening the criteria for determining the necessity of the defrosting operation, while the air heat exchanger 25 When the temperature reaches the second reference value and the necessity for defrosting further increases, defrosting is prioritized and the defrosting operation is executed. Thus, in this embodiment, while performing a defrost operation as needed, it can suppress that the hot water shortage resulting from a defrost operation arises. Moreover, since the frequency | count of a defrost operation can be reduced, it leads also to the saving of an electricity bill.

  Moreover, in the said embodiment, since the temperature data of the water measured by the temperature sensor 51,53,55 each provided in the several position where the height in the tank 15 differs in the amount of remaining hot water is used, each height is used. The temperature of the water at can be measured and the amount of water at each temperature can be evaluated.

  In the above embodiment, the reference value is the temperature of the air heat exchanger 25, and the second reference value is set to a value lower than the first reference value. The temperature of the air heat exchanger 25 is easy to measure and is highly related to the frosting state.

  In the above embodiment, the tank 15 is a small tank having a capacity of 200 L or less. In such a water heater 11, for example, even if the entire amount in the tank 15 is boiled in the midnight time zone using midnight power, additional boiling is performed in another time zone in accordance with the decrease in the amount of hot water. Necessary. Therefore, when it is necessary to additionally boil in the time zone where the amount of water used is large (second time zone), it is difficult to perform the defrosting operation as described above. It can be effectively suppressed. Further, as described above, it is difficult to perform the defrosting operation, and the defrosting operation time is somewhat delayed, so that some frost formation occurs in the air heat exchanger 25 and the heating capacity in the water heat exchanger 21 is slightly decreased. However, in the case of a small tank, the energy required for one boiling is less than in the case of other large tanks, so that the time required for boiling can be kept small. Moreover, the installation area and installation height which install the water heater 11 can be made small by using a small tank.

<Control example 2>
FIG. 3 is a flowchart showing a control example 2 of the water heater 11. In this control example 2, the control unit 33 defrosts based on the second reference value when the time zone is the second time zone and the amount of remaining hot water stored in the tank 15 is equal to or less than a predetermined amount. Determine whether driving is necessary. This point is different from the control example 1.

  That is, in step S12, the control unit 33 determines which time zone the current time is in based on the data from the clock function, and proceeds to step S14 if the time is in the second time zone. In step S14, it is determined whether the amount of remaining hot water in the tank 15 is A liter or less. The control unit 33 proceeds to step S15 when the remaining hot water amount is A liter or less, and proceeds to step S13 when the remaining hot water amount exceeds A liter. Specifically, for example, when the detected value by the temperature sensor 53 provided in the center in the height direction of the tank 15 is less than 85 ° C., it is determined that the remaining hot water amount is A liter or less.

  Therefore, in the present control example 2, the control unit 33 determines whether or not the defrosting operation is necessary according to the amount of remaining hot water in the tank 15 in addition to determining whether or not the water usage is different. That is, when the amount of remaining hot water in the tank 15 is A liter or less, the amount of hot water that can be used by the user is small. In this case, the defrosting operation is executed by tightening the criteria for determining whether or not the defrosting operation is necessary. Make it harder. Thereby, it is possible to further suppress the occurrence of running out of hot water due to the defrosting operation.

  The control of steps S11 and S16 to S19 is the same as steps S1 and S5 to S8 of control example 1. Other configurations, operations, and effects are the same as in Control Example 1 although explanations thereof are omitted.

<Other embodiments>
The present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the spirit of the present invention. For example, in the above embodiment, the case where the control is performed by dividing one day into three time zones has been described as an example. However, for example, one day may be divided into two time zones, and may be divided into four or more time zones. It may be separated.

  In the above embodiment, the first reference value is set as the reference value when the first time zone and the third time zone are set, and the second reference value is set as the reference value when the time zone is the second time zone. As an example, for example, different values are set as reference values in the first time zone, the second time zone, and the third time zone, respectively, and it is difficult to enter the defrosting operation (ease of entry). May be different from each other.

  Moreover, in the said embodiment, although the temperature of the air heat exchanger 25 was used as a physical quantity used as a reference value, for example, the pressure of the air heat exchanger 25, the elapsed time measured by a timer (for example, the previous defrosting operation end point) The elapsed time from the start, the elapsed time from the start of the boiling operation, etc.) may be used as reference values to control the ease of entry into the defrosting operation.

  In the above embodiment, carbon dioxide is used as the refrigerant. However, as the refrigerant, in addition to carbon dioxide, a refrigerant used in a supercritical state such as ethylene, ethane, or nitrogen oxide may be used. Instead of the refrigerant used in the above, a refrigerant such as dichlorodifluoromethane R-12) or chlorodifluoromethane (R-22) may be used.

DESCRIPTION OF SYMBOLS 11 Hot water supply machine 13 Refrigerant circuit 15 Tank 17 Hot water storage circuit 19 Compressor 21 Water heat exchanger 23 Expansion valve 25 Air heat exchanger 27 Intake piping 29 Hot water supply piping 31 Pump 33 Control part 35 Hot water supply piping 37 Water supply piping 39, 41, 51, 53, 55, 57, 59 Temperature sensor

Claims (2)

A refrigerant circuit (13) having a compressor (19), a water heat exchanger (21), a pressure reducing mechanism (23), and an air heat exchanger (25), in which the refrigerant circulates sequentially;
A hot water storage circuit (17) having a small tank (15) having a capacity of 200 L or less in which water is stored, and capable of heating the water by the water heat exchanger (21);
Control means (33) for determining the necessity of a defrosting operation for defrosting the air heat exchanger (25) based on a reference value based on a physical quantity capable of determining the frosting state on the air heat exchanger (25). And a heat pump type water heater provided with
One day is stored by being divided into a plurality of time zones including a first time zone and a second time zone in which the amount of water used is larger than the first time zone, and the first reference value as the reference value A storage unit that stores a second reference value that is set to a condition where frost formation is easier than the first reference value;
The control means (33)
When the time zone is the first time zone, the necessity of the defrosting operation is determined based on the first reference value regardless of the amount of remaining hot water stored in the tank (15) ,
When when the time zone is the second time period, it said regardless of remaining hot water, by determining the necessity of the defrosting operation based on the second reference value, which is the first time period A heat pump water heater that delays the time of the defrosting operation by making it more difficult to perform the defrosting operation . The heat pump type water heater according to claim 1, wherein the reference value is a temperature of the air heat exchanger (25), and the second reference value is set to a value smaller than the first reference value.

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