JP2007107825A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reliable heat pump water heater. <P>SOLUTION: The water heater comprises: a heat pump cycle including a compressor 11, a hot water supply heat exchanger 12, a decompressor 13 and an evaporator 14 successively connected, and a high-pressure protection means; a hot water supply circuit including the hot water supply heat exchanger 12 and a carrying means 17 carrying hot water; and a control means 30 controlling operation of the carrying means 17. When the high-pressure protection means is operated after defrosting operation for defrosting the evaporator 14, the carrying amount of the carrying means 17 is increased more than that before operation of the high-pressure protection means, and the heat pump cycle is then restarted, whereby the compressor 11 is protected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat pump type hot water heater that alleviates a sudden pressure increase in a heat pump cycle and realizes protection of a compressor.

Conventionally, this type of heat pump type water heater is used to maintain the start-up performance of the hot water supply operation after the completion of the defrosting operation. Had been resumed.
JP 2005-147542 A

  However, if the refrigerant pipes that make up the heat pump circuit and the pipes that make up the hot water supply circuit are long and have a large number of bends, or if scales are deposited on the heat exchanger for hot water supply, the water pressure loss will increase. The pump flow rate will decrease. Therefore, when the hot water supply operation is resumed after the defrosting operation is completed, the water flow rate does not increase, the refrigerant discharge pressure of the compressor that constitutes the heat pump cycle rises and exceeds the design pressure, and wear and failure of the components of the heat pump cycle There was a problem of being connected to.

  This invention solves the said conventional subject, and it aims at providing a reliable heat pump type hot water heater.

  In order to solve the above-mentioned conventional problems, a heat pump type hot water supply apparatus of the present invention includes a heat pump cycle in which a compressor, a heat exchanger for hot water supply, a decompression unit, and an evaporator are sequentially connected, and a high pressure protection unit is provided. When the high pressure protection means operates after a defrosting operation for defrosting the evaporator, comprising a heat exchanger, a hot water supply circuit having a conveying means for conveying hot water, and a control means for controlling the operation of the conveying means In this method, the transport amount of the transport unit is increased before the operation of the high-pressure protection unit, and the heat pump cycle is restarted.

  As a result, when the refrigerant discharge pressure of the compressor rises and exceeds the design pressure when the hot water supply operation is resumed after the defrosting operation is finished, the compressor is stopped and the hot water conveyed by the conveying means is increased. Thus, the compressor can be protected by restarting the operation of the compressor.

  The present invention can provide a heat pump type hot water heater with high reliability.

  1st invention connects a compressor, a hot water supply heat exchanger, a pressure reduction means, and an evaporator in order, a heat pump cycle having a high pressure protection means, a hot water supply heat exchanger, and a hot water supply having a conveying means for conveying hot water A circuit and a control means for controlling the operation of the conveying means, and when the high-pressure protection means is operated after the defrosting operation for defrosting the evaporator, the conveyance before the operation of the high-pressure protection means If the refrigerant discharge pressure of the compressor rises and exceeds the design pressure by increasing the transport amount of the means and restarting the heat pump cycle, the compressor is stopped and the hot water transported by the transport means is stopped. Since the operation of the compressor is resumed by increasing the amount, it is possible to prevent wear and failure of the components of the heat pump cycle and provide a highly reliable heat pump type hot water heater.

  The second aspect of the invention is an optimum transport amount corresponding to an increase in water pressure loss by increasing the transport amount for transporting hot and cold water each time the high-pressure protection means operates, particularly in the heat pump type water heater of the first invention. It is possible to set a more reliable heat pump water heater by suppressing the increase in refrigerant discharge pressure of the compressor of the heat pump water heater, preventing wear and failure of the components of the heat pump cycle. Can be provided.

  According to the third aspect of the invention, particularly in the heat pump type water heater of the first or second aspect of the invention, the number of times the high-pressure protection means is operated is counted only for a predetermined time after the defrosting operation, thereby causing a factor other than an increase in water pressure loss. When the high-pressure protection means operates, the amount of hot water transported is not increased, so that the optimum pump flow rate corresponding to the increase in water pressure loss can be set more reliably.

  In the heat pump type hot water heater according to any one of the first to third inventions, the fourth invention is characterized by not clearing the number of times the high-pressure protection means has been operated until the power to be supplied to the device is reset, Since the optimal amount of hot water transferred according to the increase in the pressure is effective during the next operation, the possibility that the high-pressure protection means based on the increase in water pressure loss will be reduced and the reliability of the heat pump water heater will be improved. At the same time, the time to reach the desired tapping temperature is shortened.

  According to a fifth aspect of the invention, in particular, in the heat pump type hot water heater according to any one of the first to fourth aspects of the present invention, the heat pump type hot water heater includes an outside air temperature detecting means for detecting an outside air temperature. It is possible to estimate the decrease in the heating capacity of the heat pump water heater at low outside temperatures and to output the optimal hot water transport amount by changing the transport amount for transporting heat. As well as improving the performance, the time until reaching the desired tapping temperature is shortened.

  The sixth invention is a product that is relatively inexpensive and stable by using carbon dioxide as a refrigerant to be used, particularly in the heat pump type water heater of any one of the first to fifth inventions. Costs can be reduced and reliability can be improved. Carbon dioxide has an ozone depletion potential of zero and a global warming potential of about 1/700 of the alternative refrigerant HFC-407C, which is very small. We can provide gentle products. Carbon dioxide is pressurized to a critical pressure or higher. By using the first to fifth inventions, a highly reliable heat pump water heater can be used even if the refrigerant is pressurized to a critical pressure or higher. Can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a heat pump type hot water heater in the first embodiment of the present invention. In FIG. 1, the heat pump type hot water heater of the present invention includes an inverter type compressor 11, a hot water supply heat exchanger 12, a pressure reducing device 13, and an evaporator 14 that are sequentially connected in an annular manner through a refrigerant pipe 15. A hot water storage unit 16 configured to connect a hot water storage tank 16 for storing hot water supply liquid, a hot water supply heat exchanger 12, and a pump 17, which is a transport means for transporting the liquid in the hot water storage tank, sequentially in an annular manner by a liquid pipe 18; Pressure detection means 21 that is a high-pressure protection control means of the inverter compressor 11, an incoming water temperature detection means 31 that detects an incoming water temperature entering the hot water supply heat exchanger 12, and a hot water temperature that is discharged from the hot water supply heat exchanger 12 The hot water temperature detecting means 32 for detecting the outside air, the outside air temperature detecting means 33 for detecting the outside air temperature, and the microcomputer 30 which is a control means for controlling the rotational speed of the pump 17 are provided. That.

In addition, the refrigerant | coolant distribute | circulated in the refrigerant | coolant piping 15 uses the comparatively cheap and stable carbon dioxide, can suppress product cost and can improve reliability. Carbon dioxide has an ozone depletion coefficient of zero, and the global warming coefficient is about 170 of the alternative refrigerant HFC-407C.
Because it is as small as 1/0, we can provide products that are friendly to the global environment.

  The operation and action of the heat pump type water heater configured as described above will be described below.

  FIG. 2 is a block diagram showing the entire operation control of the heat pump type hot water heater in the first embodiment of the present invention. In FIG. 2, the required capacity is determined by the required capacity determining means 35 based on the input value (for example, boiling temperature) from the operation unit 1 and the temperature detected by the outside air temperature detecting means 33, and the target hot water temperature is the target hot water temperature. It is determined by the determination means 37.

  Further, the output of the pump 17 is determined through the pump flow rate calculation means 38, the pump flow rate correction means 39, and the pump flow rate output means 40 from the incoming water temperature detected by the incoming water temperature detection means 31, the required capacity, and the target hot water temperature. Further, when the defrosting operation is resumed, when the pressure detection means 21 for detecting the refrigerant pressure discharged from the inverter compressor 11 reaches the design pressure, the high pressure protection control means 22 for stopping the operation of the compressor for high pressure protection. The pump flow rate calculation means 38 corrects the pump flow rate.

  The microcomputer 30 is used as the required capacity determining means 35, the target hot water temperature determining means 37, the high pressure protection control means 22, the pump flow rate calculating means 38, the pump flow rate correcting means 39, and the pump flow rate output means 40.

  FIG. 3 is a flowchart for determining the pump flow rate when the defrosting operation is restored. In FIG. 3, a predetermined value α (initial value is α = 1), a required capacity Q determined by the required capacity detection means 35 (for example, Q = 6.0 kW), and a target hot water determined by the target hot water temperature determination means 37. From the temperature Twa (for example, Twa = 65 ° C.) and the incoming water temperature T1 (for example, T1 = 17 ° C.) detected by the incoming water temperature detecting means 31, a theoretically required pump flow rate Wq is calculated by the pump flow rate calculating means 38, decide. In the present embodiment, Wq is represented by α × Y (Y is a value determined by Q, Twa, and T1), and Y is multiplied by a predetermined value α, but is not limited thereto. For example, Wq may be Y + γ (γ is an arbitrary number).

  Further, the pump flow rate correction means 39 determines the maximum pump flow rate value Wqmax. The pump flow rate output means 40 determines the output value qw (= Wq / Wqmax) of the pump 17 from Wq and Wqmax.

  Here, if the liquid pipe 18 is long and the number of times of bending is large, or if the water pressure loss increases due to the deposition of scale on the hot water supply heat exchanger 12, the pump flow rate is reduced compared to the normal time. When the discharge refrigerant pressure of the heat pump type hot water heater after the frost operation is increased and the pressure detection means 21 determines that the discharge pressure has reached the design pressure, the high pressure protection control means 22 stops the operation of the compressor. Then, β (for example, β = 0.2) is added to the value of the predetermined value α to set a new predetermined value α. By doing in this way, since the value of (alpha) increases and the pump flow rate output in connection with it increases, the raise of the discharge refrigerant | coolant pressure of the heat pump type hot water heater after completion | finish of a defrost operation can be prevented. The value of β is not limited to 0.2, and may be changed according to the usage situation.

FIG. 4 is a flowchart for determining the pump flow rate when the operation of the compressor is stopped a plurality of times. As shown in FIG. 4, the number of times the operation of the compressor is stopped because the discharge refrigerant pressure reaches the design pressure. The predetermined value α may be determined according to the count number. In this case, α = 1 + β × N is configured, and α is determined according to the number N of times the operation of the compressor is stopped. By adopting such a configuration, it is possible to determine the pump flow rate according to the number of counts and to set the optimal pump flow rate, so that it is possible to more reliably prevent the discharge refrigerant pressure of the heat pump water heater from increasing. it can.

  Further, since the count number is not cleared except at the time of resetting the power supply, it is possible to operate at the optimum pump flow rate due to water pressure loss even at the next operation, so that the time is shortened until the desired hot water temperature is reached.

  As described above, in the present embodiment, since the necessary pump flow rate can always be output, it is possible to prevent the discharge refrigerant pressure from rising when the heat pump water heater is restarted after the defrosting operation is resumed. It is possible to protect mechanical wear such as.

(Embodiment 2)
The configuration and operation control of the heat pump type hot water heater in the second embodiment of the present invention are the same as the configuration of the heat pump type hot water heater in the first embodiment, and the same portions are denoted by the same reference numerals. Description is omitted.

  FIG. 5 is a flowchart for determining the pump flow rate of the heat pump type water heater in the second embodiment. In the second embodiment, only the method of counting the number of times the compressor has stopped is different, and the others are the same as those in the first embodiment, so the description is omitted.

  In FIG. 5, in the second embodiment, the pump flow rate is determined according to the number N of times the compressor operation is stopped, but within X minutes after the compressor is restarted after the compressor operation is stopped. It does not count. Therefore, if the time when the compressor is stopped has passed X minutes after restarting the compressor, it is counted, and if it has not passed X minutes, it is not counted.

  By performing the control as described above, it is not necessary to change the pump rotation speed when the compressor is stopped due to a factor other than water pressure loss (for example, when the incoming water temperature suddenly rises just before the boiling of the hot water tank 16 is completed). . Even if the compressor stops due to factors other than water pressure loss, if the pump flow rate is increased, it takes time to obtain the desired tapping temperature. Therefore, even when the compressor stops due to a factor other than the water pressure loss, it is possible to set the optimum pump flow rate according to the increase in the water pressure loss more reliably.

(Embodiment 3)
The configuration of the heat pump type water heater in the third embodiment of the present invention is the same as the configuration of the heat pump type hot water heater in the first embodiment. To do.

  FIG. 6 is a block diagram showing the overall operation control of the heat pump type hot water heater in the third embodiment of the present invention. In FIG. 6, the required capacity is determined by the required capacity determining means 35 based on the input value (for example, the boiling temperature) from the operation unit 1 and the temperature detected by the outside air temperature detecting means 33, and the target hot water temperature is the target hot water temperature. It is determined by the determination means 37.

  The pump output is determined through the pump flow rate calculation means 38, the pump flow rate correction means 39, and the pump flow rate output means 40 from the incoming water temperature detected by the incoming water temperature detection means 31, the required capacity, and the target hot water temperature. Further, when the defrosting operation is resumed, when the pressure detection means 21 for detecting the refrigerant pressure discharged from the inverter compressor 11 reaches the design pressure, the high pressure protection control means 22 for stopping the operation of the compressor for high pressure protection. The pump flow rate calculation means 38 corrects the pump flow rate. Further, the pump flow coefficient determining means 41 calculates the pump flow coefficient C from the outside air temperature detected by the outside air temperature detecting means 33, and the pump flow rate output by the pump flow rate output means 40 is corrected by the flow coefficient C.

  FIG. 7 is a flowchart for determining the pump flow rate of the heat pump type hot water heater in the third embodiment of the present invention. In FIG. 7, the pump flow rate coefficient C is determined from the outside air temperature Tg detected by the outside air temperature detecting means 33, and the pump flow rate output means 40 corrects the output pump flow rate.

  FIG. 8 is a diagram showing the relationship between the outside air temperature and the heating capacity, and FIG. 9 is a diagram showing the value of the pump flow coefficient C according to the outside air temperature.

  As shown in FIG. 8, at a low outside air temperature, the heating capacity is reduced due to the influence of frost generated in the evaporator. Therefore, by correcting the lack of capacity when the outside air temperature decreases with the pump flow coefficient coefficient C as shown in FIG. 9 calculated by the pump flow coefficient determining means 41, the heat pump water heater at the low outside air temperature is corrected. It is possible to estimate the decrease in heating capacity and output the optimal pump flow rate, and to protect the wear of compressors and other mechanisms by suppressing the increase in refrigerant pressure of the heat pump water heater when water pressure loss increases Can do.

  The required capacity determining means 35, target hot water temperature determining means 37, high pressure protection control means 22, pump flow rate calculating means 38, pump flow rate correcting means 39, pump flow rate output means 40, and pump flow coefficient determining means 41 include a microcomputer. 30 is used.

  The heat pump type hot water heater according to the present invention realizes protection of the compressor by alleviating a sudden pressure increase after restarting the compressor operation, and in particular, a heat pump type hot water heater and various heat pump devices that are pressurized to a critical pressure or higher. It is useful as an application.

Configuration schematic diagram of heat pump type water heater in Embodiment 1 of the present invention Operation control diagram of the heat pump water heater Operation control flowchart of the heat pump type water heater Other operation control flowchart of the heat pump type water heater Operation control flowchart of heat pump type hot water heater in Embodiment 2 of the present invention Operation control diagram of heat pump water heater in Embodiment 3 of the present invention Operation control flowchart of the heat pump type water heater Operational illustration of the heat pump water heater Relationship diagram between pump flow coefficient and outside air temperature of the same heat pump type water heater

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Operation part 11 Inverter type compressor 12 Heat exchanger for hot water supply 13 Depressurizer 14 Evaporator 15 Refrigerant piping 16 Hot water storage tank 17 Pump 18 Liquid piping 19 Fan 20 Fan motor 21 Pressure detection means 30 Microcomputer 31 Incoming water temperature detection means 32 Hot water supply Temperature detection means 33 Outside air temperature detection means

Claims (6)

Compressor, heat exchanger for hot water supply, decompression means, evaporator sequentially connected, heat pump cycle having high pressure protection means, hot water supply heat exchanger, hot water supply circuit having transport means for transporting hot water, and transport means Control means for controlling the operation of the high-pressure protection means when the high-pressure protection means is operated after the defrosting operation for defrosting the evaporator, the amount of conveyance of the conveyance means is increased from before the operation of the high-pressure protection means And a heat pump type hot water supply device, wherein the heat pump cycle is restarted. 2. The heat pump type hot water supply apparatus according to claim 1, wherein a transport amount for transporting hot water is increased each time the high pressure protection means operates. The heat pump hot water supply device according to claim 1 or 2, wherein the number of times the high-pressure protection means is operated is counted for a predetermined time after the defrosting operation. The heat pump type hot water supply apparatus according to any one of claims 1 to 3, wherein the number of times the high-pressure protection means has been operated is not cleared until a power source to be supplied to the device is reset. 5. The apparatus according to claim 1, further comprising an outside air temperature detection unit configured to detect an outside air temperature, wherein a conveyance amount for conveying hot water is changed based on a detection value of the outside air temperature detection unit. The heat pump type hot water supply apparatus described in 1. The heat pump hot water supply apparatus according to any one of claims 1 to 5, wherein the refrigerant to be used is carbon dioxide.

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