JP2008039272A - Heat pump type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump type water heater capable of preventing abnormal temperature rise and abnormal pressure rise of a compressor even when an operation is continued until the temperature of the water flowing into a water-refrigerant heat exchanger becomes high temperature, securing reliability of the compressor and each of the devices, and performing efficient hot water supply and heating operation. <P>SOLUTION: The heat pump type water heater includes a water inflow temperature detecting means 31 for detecting a water inflow temperature of the water-refrigerant heat exchanger 12, a hot water outflow temperature detecting means 33 for detecting a hot water outflow temperature of the water-refrigerant heat exchanger, and a control means 30 for deciding a target hot water outflow temperature of the water-refrigerant heat exchanger 12 according to a boiling-up temperature of a hot water storage tank, and controlling a flow rate of the pump so that a detection value of the hot water outflow temperature detecting means 33 is agreed with the target hot water outflow temperature, and a maximum value is set as the target hot water outflow temperature when the detection value of the water inflow temperature detecting means 31 is a prescribed value or more. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The heat pump type hot water heater according to the present invention relates to control that prevents an abnormal temperature rise and an abnormal pressure rise of a compressor.

2. Description of the Related Art Conventionally, there is a heat pump type water heater that sets the boiling set temperature lower as the outside air temperature or the feed water temperature becomes higher (see, for example, Patent Document).
JP 2002-147846 A

  However, if the operation is continued until the temperature of the water flowing into the water-refrigerant heat exchanger becomes high in order to boil high-temperature water, the abnormal temperature rise and abnormal pressure rise of the compressor will cause damage to the compressor. There was a problem that it would end up.

  The present invention solves the above-described conventional problems, and prevents abnormal temperature rise and abnormal pressure rise of the compressor even if the operation is continued until the water temperature flowing into the water-refrigerant heat exchanger becomes high, An object of the present invention is to ensure the reliability of the compressor and each device and realize an efficient hot water heating operation.

  In order to solve the above-described conventional problems, a heat pump water heater of the present invention includes a heat pump cycle configured by annularly connecting a compressor, a water-refrigerant heat exchanger, a decompression device, and an evaporator with a refrigerant pipe, Hot water storage tank that stores hot water, a pump that circulates the hot water in the hot water storage tank, a hot water supply circuit that is formed by connecting water-refrigerant heat exchangers in a ring shape, and the water-refrigerant heat exchanger temperature detection A water temperature detecting means, a hot water temperature detecting means for detecting a hot water temperature of the water-refrigerant heat exchanger, a target hot water temperature of the water-refrigerant heat exchanger is determined according to a boiling temperature of the hot water storage tank, Control means for controlling the flow rate of the pump so that the detected value of the temperature detecting means becomes the target hot water temperature, and when the detected value of the incoming water temperature detecting means is a predetermined value or more, the target hot water temperature is reached. Maximum value Operation, it is possible to continue the operation until the temperature of the water flowing into the water-refrigerant heat exchanger reaches a high temperature, allowing high-temperature boiling, as well as abnormal compressor temperature rise, abnormal pressure rise, and water-refrigerant heat exchange. It is possible to prevent the scale from adhering to the vessel.

  The heat pump type water heater of the present invention prevents an abnormal temperature rise and abnormal pressure rise of the compressor even if the operation is continued until the temperature of the water flowing into the water-refrigerant heat exchanger becomes high. Can be ensured, and an efficient hot water heating operation can be realized.

A heat pump type hot water supply apparatus according to a first aspect of the invention includes a heat pump cycle configured by connecting a compressor, a water-refrigerant heat exchanger, a decompression device, and an evaporator in a ring shape with a refrigerant pipe, a hot water storage tank for storing hot water, and the hot water storage A pump that circulates hot water in the tank, a hot water supply circuit that is formed by connecting water-refrigerant heat exchangers in an annular shape by piping, an incoming water temperature detecting means that detects an incoming water temperature of the water-refrigerant heat exchanger, A hot water temperature detecting means for detecting the hot water temperature of the refrigerant heat exchanger, a target hot water temperature of the water-refrigerant heat exchanger is determined according to the boiling temperature of the hot water storage tank, and the detected value of the hot water temperature detecting means is: Control means for controlling the flow rate of the pump so as to achieve the target hot water temperature, and when the detection value of the incoming water temperature detection means is a predetermined value or more, by setting a maximum value to the target hot water temperature, Water-refrigerant It is possible to continue the operation until the temperature of the water flowing into the exchanger reaches a high temperature, and it is possible to boil high temperature, and to prevent abnormal temperature rise and abnormal pressure rise of the compressor and scale adhesion of the water-refrigerant heat exchanger. it can.

  A heat pump type hot water supply apparatus according to a second aspect of the present invention includes a compressor, a water-refrigerant heat exchanger, a decompression device, a heat pump cycle formed by connecting an evaporator in an annular shape by a refrigerant pipe, a hot water storage tank for storing hot water, and the hot water storage A pump that circulates hot water in the tank, a hot water supply circuit that is formed by connecting water-refrigerant heat exchangers in an annular shape by piping, an incoming water temperature detecting means that detects an incoming water temperature of the water-refrigerant heat exchanger, The hot water temperature detecting means for detecting the hot water temperature of the refrigerant heat exchanger, the outdoor air temperature detecting means for detecting the outdoor air temperature, and the target hot water temperature of the water-refrigerant heat exchanger are determined according to the boiling temperature of the hot water storage tank. And a control means for controlling the flow rate of the pump so that the detected value of the hot water temperature detecting means becomes the target hot water temperature, the detected value of the incoming water temperature detecting means is not less than a predetermined value, and the outside air temperature is Predetermined territory At this time, by setting a maximum value for the target hot water temperature, even if the incoming water temperature is equal to or higher than a predetermined temperature, the maximum value of the target hot water temperature only in the outside air temperature region that causes an abnormal temperature increase and abnormal pressure increase of the compressor. Therefore, it is possible to maintain the reliability of the compressor without unnecessarily lowering the boiling temperature and to continue the operation until the temperature of the water flowing into the water-refrigerant heat exchanger becomes high. Can be raised.

  In the heat pump type hot water heater of the third aspect of the invention, particularly in the first or second aspect of the invention, by setting a predetermined value of the incoming water temperature that sets the maximum value to the target hot water temperature according to the outside air temperature, Since the maximum target hot water temperature is set only in the outside air temperature range and the incoming water temperature region that cause temperature rise and abnormal pressure rise, ensuring the reliability of the compressor without unnecessarily raising the boiling temperature, and the water-refrigerant heat exchanger The operation can be continued until the temperature of the water flowing into the water reaches a high temperature, and the hot water tank can be heated to a high temperature.

  In the heat pump type hot water heater of the fourth invention, in particular, in the first to third inventions, the compressor has a configuration without an accumulator, so there is no accumulator. Weight reduction is possible.

  The heat pump type water heater of the fifth invention is the first to fourth inventions, in particular, even if the refrigerant pressure on the high pressure side is equal to or higher than the critical pressure, the water is deprived of heat and the refrigerant temperature decreases. Since it does not condense, it becomes easy to form a temperature difference between the refrigerant and water in the entire water-refrigerant heat exchanger, so that hot water can be obtained and the heat exchange rate can be increased.

  The heat pump type hot water heater of the sixth invention, in particular, in the fifth invention, reduces the product cost by using carbon dioxide, which is relatively inexpensive and stable, as the refrigerant used is carbon dioxide. At the same time, reliability can be improved. In addition, carbon dioxide has an ozone depletion coefficient of zero and a global warming coefficient of about 1/700 of the alternative refrigerant HFC-407C, which is very small.

  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 configuration diagram of a heat pump type water heater in the present embodiment. In FIG. 1, the heat pump cycle of the heat pump type hot water heater in the present embodiment includes an inverter type compressor 11, a water-refrigerant heat exchanger 12, a decompression device 13, and an evaporator 14 that are sequentially connected in an annular manner through a refrigerant pipe 15. It is configured. On the other hand, the hot water supply circuit of the heat pump water heater in the present embodiment stores hot water and a hot water storage tank 16 having a microcomputer for calculating a desired boiling temperature, and the hot water in the hot water storage tank 16 is converted into a water-refrigerant heat exchanger 12. The pump 17 and the water-refrigerant heat exchanger 12 that are introduced into the hot water supply circuit and circulated in the hot water supply circuit are sequentially connected in a ring shape by the liquid pipe 18. If the inverter compressor 11 is configured without an accumulator, the heat pump water heater can be reduced in size and weight. However, the present invention is not limited to this, and the compressor configured without an accumulator is used. There is no problem even if the machine is used. In addition, since the high-pressure side uses carbon dioxide whose critical pressure exceeds the critical pressure, the refrigerant circulating in the heat pump cycle is condensed even if the temperature is lowered due to the heat deprived of the water flowing in the water-refrigerant heat exchanger 12. Therefore, it becomes easy to form a temperature difference between the refrigerant and water in the water-refrigerant heat exchanger, high-temperature hot water can be obtained, and the heat exchange efficiency can be increased.

  In addition, a thermistor 31 serving as a water temperature detecting means for detecting the temperature of hot water entering the water-refrigerant heat exchanger 12 is disposed at the water inlet of the water-refrigerant heat exchanger 12, and water-refrigerant heat exchange is performed. A thermistor 33 serving as a hot water temperature detecting means for detecting the temperature of hot water discharged from the water-refrigerant heat exchanger 12 is disposed at the water outlet of the water heater 13, and is located in the vicinity of the evaporator 14 that exchanges heat with the atmosphere. A thermistor 34, which is an outside air temperature detecting means for detecting the outside air temperature, is provided to detect a desired boiling temperature determined by the hot water storage tank 16, and a target hot water temperature that is a target value detected by the hot water temperature detecting means. And a microcomputer 30 (control means) for controlling the flow rate of the pump 17 so as to reach the target hot water temperature.

  FIG. 2 is a configuration diagram of operation control according to the present embodiment. FIG. 2 shows a configuration in which the pump 17 is controlled so as to reach a target hot water temperature determined by the incoming water temperature detected by the incoming water temperature detecting means 31 and a desired boiling temperature determined by the hot water storage tank 16. ing.

  FIG. 3 is a flowchart according to the control of the present embodiment. The control of the present invention will be described with reference to FIGS. First, the target hot water temperature of the water-refrigerant heat exchanger 12 is determined based on the boiling temperature of the hot water storage tank 16. Next, it is determined whether or not the incoming water temperature detected by the incoming water temperature detecting means 31 is equal to or higher than an arbitrary predetermined temperature. If the incoming water temperature is equal to or higher than the predetermined temperature, a maximum value is set for the target hot water temperature. Thus, the boiling temperature is limited, and the flow rate of the pump 17 is controlled so that the target hot water temperature becomes the maximum value. When the incoming water temperature is lower than a predetermined temperature, the maximum target hot water temperature limit is released, and the flow rate of the pump 17 is limited so that the target hot water temperature determined by the boiling temperature is reached. For example, when the incoming water temperature is lower than a predetermined temperature, the target hot water temperature is set to 90 ° C., and when the incoming water temperature is higher than the predetermined temperature, the flow rate of the pump 17 is set so that the target hot water temperature is 80 ° C. Control. As shown in FIGS. 4 and 5, the predetermined temperature of the incoming water temperature, which is the determination value for setting the maximum value, may always use either a constant temperature or a temperature set for each outside air temperature. However, if the temperature set for each outside air temperature is used, the incoming water temperature can be set higher depending on the outside air temperature, so that the boiling temperature is not unnecessarily lowered.

  FIG. 6 is a diagram comparing various values between the present embodiment and the conventional embodiment. In FIG. 6, the embodiment of the present invention is indicated by a solid line, and the conventional embodiment is indicated by a dotted line. The incoming water temperature is indicated by the same value as that of the embodiment of the present invention and the conventional embodiment, and increases with time.

  In the conventional embodiment, the target hot water temperature determined by the boiling temperature of the hot water storage tank 16 is controlled to be constant regardless of the incoming water temperature. Therefore, after the incoming water temperature exceeds a predetermined value, The pressure of the discharged refrigerant exceeded the design pressure, and the compressor had to be stopped to protect the compressor.

On the other hand, in the present embodiment, the target temperature is determined by the boiling temperature of the hot water storage tank 16, but after the incoming water temperature exceeds a predetermined value, the maximum value is set as the target hot water temperature, Since the pump 17 is controlled so as to reach the maximum value, the operation of the refrigerant can be continued without exceeding the design pressure of the refrigerant discharged from the compressor, so that the hot water tank 16 can be heated to a high temperature.

  As described above, in the present embodiment, the target hot water temperature is set to a maximum value and the target hot water temperature is limited, so that the operation is continued until the water temperature flowing into the water-refrigerant heat exchanger becomes high. Boiling is possible, and abnormal temperature rise and abnormal pressure rise of the compressor and scale adhesion of the water-refrigerant heat exchanger can be prevented.

(Embodiment 2)
FIG. 7 is a configuration diagram of operation control according to the present embodiment. In FIG. 7, the target hot water temperature determined by the incoming water temperature detected by the incoming water temperature detecting means 31, the desired boiling temperature determined by the hot water storage tank 16, and the outside air temperature detected by the outside air temperature detecting means 34. Thus, the configuration in which the pump 17 is controlled is shown. In addition, since the structure of the heat pump type water heater in this Embodiment is the same as the structure of the heat pump type water heater in Embodiment 1, description is abbreviate | omitted.

  FIG. 8 is a flowchart according to the control of the present embodiment. The control of the present invention will be described with reference to FIGS. First, the target hot water temperature of the water-refrigerant heat exchanger 12 is determined based on the boiling temperature of the hot water storage tank 16. Next, it is determined whether or not the incoming water temperature detected by the incoming water temperature detecting means 31 is equal to or higher than an arbitrary predetermined temperature. If the incoming water temperature is higher than or equal to the predetermined temperature, the outside air temperature detecting means 34 is then used. It is determined whether or not the detected outside air temperature is within a predetermined temperature range. If the outside air temperature is within the predetermined temperature range, the boiling temperature is limited by setting a maximum value for the target hot water temperature. When the flow rate of the pump 17 is controlled so that the hot water temperature becomes the maximum value, and the outside air temperature is outside the predetermined temperature range, the maximum hot water temperature limit is canceled and the target hot water temperature determined by the boiling temperature is released. The flow rate of the pump 17 is controlled to reach the temperature. Further, even when the incoming water temperature is lower than the predetermined temperature, the maximum value restriction of the target hot water temperature is released, and the flow rate of the pump 17 is controlled so as to be the target hot water temperature determined by the boiling temperature. As shown in FIGS. 4 and 5, the predetermined temperature of the incoming water temperature, which is the determination value for setting the maximum value, may always use either a constant temperature or a temperature set for each outside air temperature. However, if the temperature set for each outside air temperature is used, the incoming water temperature can be set higher depending on the outside air temperature, so that the boiling temperature is not unnecessarily lowered.

  As described above, in the present embodiment, the target hot water temperature is set to a maximum value and the target hot water temperature is limited, so that the operation is continued until the water temperature flowing into the water-refrigerant heat exchanger becomes high. Boiling is possible, and abnormal temperature rise and abnormal pressure rise of the compressor and scale adhesion of the water-refrigerant heat exchanger can be prevented.

  As described above, the boiling control in the heat pump type hot water heater according to the present invention includes the integrated heat pump type hot water heater in which the hot water storage tank and the heat pump cycle are integrated, and the hot water heated by the water-refrigerant heat exchanger is directly discharged. It can also be applied to instantaneous water heating operation.

Configuration diagram of heat pump water heater in Embodiments 1 and 2 Configuration diagram of operation control in Embodiment 1 Control flowchart in Embodiment 1 Other control flowcharts in the first and second embodiments Incoming water temperature setting diagram for other controls in the first and second embodiments Comparison diagram with the first embodiment in the first embodiment Configuration diagram of operation control in Embodiment 2 Control flowchart in Embodiment 2

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Inverter type compressor 12 Water-refrigerant heat exchanger 13 Pressure reducing device 14 Evaporator 15 Refrigerant piping 16 Hot water storage tank 17 Pump 18 Liquid piping 30 Microcomputer (control means)
31 Thermistor (Incoming water temperature detection means)
33 Thermistor (Tapping temperature detection means)
34 Thermistor (Outside temperature detection means)

Claims (6)

Compressor, water-refrigerant heat exchanger, decompression device, heat pump cycle configured by connecting the evaporators in an annular shape by refrigerant piping, a hot water storage tank for storing hot water, a pump for circulating hot water in the hot water storage tank, water A hot water supply circuit constructed by connecting refrigerant heat exchangers in an annular shape by piping, an incoming water temperature detecting means for detecting the incoming water temperature of the water-refrigerant heat exchanger, and a hot water outlet for detecting the outlet temperature of the water-refrigerant heat exchanger The target hot water temperature of the water-refrigerant heat exchanger is determined according to the temperature detection means and the boiling temperature of the hot water storage tank, and the flow rate of the pump is set so that the detected value of the hot water temperature detection means becomes the target hot water temperature. A heat pump type hot water heater, wherein a maximum value is set to the target hot water temperature when the detected value of the incoming water temperature detecting means is a predetermined value or more. Compressor, water-refrigerant heat exchanger, decompression device, heat pump cycle configured by connecting the evaporators in an annular shape by refrigerant piping, a hot water storage tank for storing hot water, a pump for circulating hot water in the hot water storage tank, water A hot water supply circuit constructed by connecting refrigerant heat exchangers in an annular shape by piping, an incoming water temperature detecting means for detecting the incoming water temperature of the water-refrigerant heat exchanger, and a hot water outlet for detecting the outlet temperature of the water-refrigerant heat exchanger A temperature detection means, an outside air temperature detection means for detecting the outside air temperature, a target hot water temperature of the water-refrigerant heat exchanger is determined according to the boiling temperature of the hot water storage tank, and the detection value of the hot water temperature detection means is: Control means for controlling the flow rate of the pump so as to achieve the target hot water temperature, and when the detected value of the incoming water temperature detecting means is a predetermined value or more and the outside air temperature is in a predetermined region, the target hot water temperature is reached. Maximum value Heat pump water heater, characterized by a constant. The heat pump type hot water heater according to claim 1 or 2, wherein a predetermined value of an incoming water temperature that sets a maximum value as a target hot water temperature is set according to an outside air temperature. The heat pump type hot water supply apparatus according to any one of claims 1 to 3, wherein the compressor has a structure without an accumulator. The heat pump type water heater according to any one of claims 1 to 4, wherein the refrigerant pressure on the high pressure side is equal to or higher than a critical pressure. The heat pump type hot water heater according to claim 5, wherein the refrigerant to be used is carbon dioxide.

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