JP5092692B2 - Heat pump water heater - Google Patents

Description

  The present invention relates to a heat pump water heater.

  Conventionally, a hot water supply apparatus using various heat pump cycles has been proposed, and there is one shown in FIG. 3 (for example, see Patent Document 1).

  FIG. 3 is a block diagram of a conventional heat pump water heater described in the publication. In FIG. 3, a refrigerant circulation circuit including a compressor 1, a heat storage device 2, a heat storage heat transfer tube 3, an expansion device 4, and an evaporator 5, a heat storage device 2, a water supply pipe 11, a hot water transfer heat transfer pipe 12, and a flow rate control valve 13. And a hot water supply circuit to which a mixing valve 14, a bypass pipe 15, and a hot water supply pipe 16 are connected.

  When performing heat storage, the high-temperature and high-pressure superheated gas discharged from the compressor 1 flows into the heat storage device 2 and exchanges heat with the heat storage material (not shown) of the heat storage device 2 when flowing through the heat storage heat transfer pipe 3. Cooled and condensed. The refrigerant exiting the heat storage heat transfer tube 3 is decompressed by the expansion device 3 and flows into the evaporator 4, where it absorbs atmospheric heat to evaporate and returns to the compressor 1.

  When the heat storage operation is terminated, a high pressure cutoff pressure switch 6 is provided on the discharge side of the compressor 1, and the operation of the compressor 1 is stopped when the high pressure of the refrigerant circuit reaches a predetermined value. The predetermined value of the high pressure is the high pressure of the refrigerant when the temperature of the heat storage material reaches the temperature immediately after the end of heat storage in the latent heat region.

When hot water is supplied, one of the tap water passes through the water supply pipe 11 and is introduced into the heat transfer pipe 12 for hot water, and heat exchange with the heat storage material of the heat storage device 2 is performed to heat the tap water. The heated tap water passes through the flow control valve 13 and flows into the mixing valve 14. The other of the tap water passes through the water supply pipe 11 and the bypass pipe 15 and flows into the mixing valve 14. The mixing valve 14 mixes to a desired temperature and supplies hot water from the hot water supply pipe 16.
JP 2004-101031 A

  However, in the conventional configuration, the operation control at the time of the heat storage operation is not particularly described and is unclear. However, it is not necessarily a highly efficient operation, and there is a problem that the operation efficiency is poor.

  This invention solves the said conventional subject, and it aims at providing the heat pump hot-water supply apparatus excellent in the energy-saving property operate | moved by a highly efficient cycle.

In order to solve the conventional problems, a heat pump water heater of the present invention is heated using a heat pump cycle in which a compressor, a heat exchanger for hot water supply, a throttling device, and an evaporator are connected by piping, and the heat pump cycle. A heat storage unit for storing heat by circulating the liquid, and a water temperature detecting means for detecting the temperature of water input to the heat exchanger for hot water supply, and the heat storage unit, the circulation pump, and the heat exchanger for hot water supply are connected by piping. Based on the temperature detected by the incoming water temperature detecting means, a target value of the hot water temperature which is the temperature of the water outlet of the hot water supply heat exchanger is determined, and the target value is set higher than the incoming water temperature. and sets, when the temperature detected by the entering-water temperature detecting means is low, if the target hot water temperature below the temperature detected by the entering-water temperature detecting means higher, setting a high target hot water temperature Since the target temperature of the water outlet of the hot water supply heat exchanger is set according to the temperature of the water inlet of the hot water supply heat exchanger, it is highly efficient when storing heat in the heat storage unit. It can be operated in a cycle and has excellent energy savings.

  ADVANTAGE OF THE INVENTION According to this invention, when storing heat in a thermal storage unit, it can drive | operate with a highly efficient cycle and can provide the heat pump hot-water supply apparatus excellent in energy-saving property.

1st invention is the heat pump cycle which connected the compressor, the heat exchanger for hot water supply, the expansion device, and the evaporator with piping, and the heat storage unit which accumulates heat by circulating the liquid heated using the heat pump cycle, A water temperature detector for detecting the temperature of water entering the hot water heat exchanger, the heat storage unit, the circulation pump, and the heat exchanger for hot water are connected by piping, and detected by the water temperature detector. Based on the temperature, the target value of the hot water temperature that is the temperature of the water outlet of the hot water supply heat exchanger is determined , the target value is set higher than the incoming water temperature, and the temperature detected by the incoming water temperature detecting means is low, the target hot water temperature lower, front case fill water temperature detected by the detecting means temperature is high, characterized in setting a higher target hot water temperature, the water inlet of the hot water supply heat exchanger temperature Depending on, because it sets the target temperature of the water outlet of the hot water supply heat exchanger can be operated at high efficiency cycle, is excellent in energy saving property.

In addition, when the temperature detected by the incoming water temperature detecting means is low, the target hot water temperature is set low, and when the temperature detected by the incoming water temperature detecting means is high, the target hot water temperature is set high. Since the temperature difference between the water inlet temperature and the water outlet temperature of the heat exchanger is controlled so as not to become too small, the heat exchanger can be operated in a highly efficient cycle, and is excellent in energy saving.

In particular, according to a second aspect of the present invention, in the heat pump water heater of the first aspect of the present invention, an outside air temperature detecting means is provided, and the target hot water temperature is set lower as the temperature detected by the outside air temperature detecting means is lower. Since the water outlet temperature of the hot water supply heat exchanger is controlled more finely according to the outside air temperature and the water inlet temperature of the hot water supply heat exchanger, it can be operated in a highly efficient cycle and has excellent energy savings. Yes.

According to a third aspect of the invention , in particular, in the first or second aspect of the invention , a hot water temperature detecting means is provided at the water outlet of the hot water supply heat exchanger so that the hot water temperature detected by the hot water temperature detecting means becomes a target hot water temperature. It is characterized by controlling the number of rotations of the circulation pump. When the target hot water temperature is changed, the control stability and followability can be controlled to the target temperature with good control.

A fourth invention is characterized in that, in particular, in any one of the first to third inventions , the heat storage unit is composed of a latent heat storage material and a liquid circulation path, and the amount of heat storage per unit volume. However, since more latent heat storage materials are used than water, it is possible to reduce the size when storing the same amount of heat.

In particular, the fifth aspect of the invention is that in any one of the first to fourth aspects of the invention , the refrigerant used in the heat pump cycle is carbon dioxide, and the high pressure side is operated in a state exceeding the critical pressure. When the refrigerant leaks to the outside, the impact on global warming 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 present embodiment.

(Embodiment 1)
FIG. 1 is a circuit configuration diagram of the heat pump water heater in the first embodiment of the present invention. In FIG. 1, the refrigeration circuit of the heat pump hot-water supply apparatus in the 1st Embodiment of this invention is demonstrated.

  In the heat pump cycle 20, a compressor 21, a hot water supply heat exchanger 22, an expansion valve 23 that is a throttling device, and an evaporator 24 are connected by piping. Further, a fan 25 for blowing air to the evaporator 24 is provided. Further, an outside air temperature detecting means 26 for detecting the suction temperature of the evaporator 24 is provided. The heat pump hot water supply apparatus according to the present embodiment preferably uses carbon dioxide as a refrigerant and operates on the high pressure side in a state exceeding the critical pressure.

  Next, a hot water supply circuit of the heat pump hot water supply apparatus in the first embodiment of the present invention will be described.

  The heat storage unit 31 includes a latent heat storage material 32 and a liquid circulation path 33. The first bottom pipe 34 of the heat storage unit 31 is connected to a water supply pipe 36 such as a water pipe via a pressure reducing valve 35. The second bottom pipe 37 of the heat storage unit 31 is connected to the inflow side of the water pipe 22 </ b> A of the hot water supply heat exchanger 22 through the circulation pump 38 and is connected to the first upper pipe 39 of the heat storage unit 31. Yes. Further, an inlet water temperature detecting means 22B is installed on the inlet side of the water pipe 22A of the hot water supply heat exchanger 22, and an outlet water temperature detecting means 22C is installed on the outlet side. Moreover, the 2nd upper piping 40 of the thermal storage unit 31 is connected to faucets and bath terminals (not shown), such as a kitchen or a washroom.

  The controller 50 includes a target hot water temperature setting means 51 and a circulation pump rotational speed control means 52, and controls the rotational speed of the circulation pump 38 so that the hot water temperature becomes the target hot water temperature.

  Next, the heat storage operation of the heat pump water heater in the first embodiment of the present invention will be described.

  First, when the user opens the faucet, the hot water is discharged from the second upper pipe 41. When the remaining heat storage amount of the heat storage unit 31 decreases, the compressor 21 starts and the heat pump cycle 20 starts operation. The refrigerant compressed by the compressor 21 dissipates heat in the hot water supply heat exchanger 22, is decompressed by the expansion valve 23, absorbs heat in the evaporator 24, and is sucked into the compressor 21 in a gas state. The fan 25 is set to a rotational speed corresponding to the operating state of the compressor 21.

  Water from the heat storage unit 31 by the circulation pump 38 passes through the second bottom pipe 37 of the heat storage unit 31 and is led to the water pipe 22A of the hot water supply heat exchanger 22 and is heated to high-temperature hot water. Inflow.

  FIG. 2 is a flowchart of operation control of the heat pump water heater in the first embodiment of the present invention. Next, operation control of the heat pump water heater in the first embodiment of the present invention will be described using the flowchart of FIG.

  First, when the user opens the faucet, the hot water is discharged from the second upper pipe 41. When the remaining heat storage amount of the heat storage unit 31 decreases, the compressor 21 starts and the heat pump cycle 20 starts operation (step 1). Next, the incoming water temperature detection means 22B, the outgoing hot water temperature detection means 22C, and the outside air temperature detection means 26 detect the incoming water temperature, the outgoing hot water temperature, and the outside air temperature, respectively (step 2). Next, the target hot water temperature setting means 51 sets the target hot water temperature to a temperature represented by (Table 1) based on the detected incoming water temperature and outside air temperature (step 3).

  Next, the number of rotations of the circulation pump 38 is controlled so as to reach the hot water temperature represented by (Table 1) (step 4).

  Here, although the rotation speed control of the compressor is not particularly described, an appropriate compressor rotation speed is set according to the incoming water temperature and the outside air temperature. Also, although the opening control of the expansion valve is not specifically described, an appropriate target discharge temperature is set according to the incoming water temperature and the outside air temperature, and the expansion valve opening control is performed so as to reach this target discharge temperature. It is carried out.

  Therefore, the target hot water temperature is set according to the incoming water temperature and the outside air temperature, and the flow rate of the circulation pump is controlled to reach this target temperature, so it can be operated in a highly efficient cycle and has excellent energy savings. .

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

  In this embodiment, the latent heat storage agent is not particularly described, but one type of latent heat storage agent or two or more types of latent heat storage agents having different melting points may be filled.

  Moreover, although this Embodiment demonstrated using the heat pump hot-water supply apparatus provided with the heat pump cycle 20, you may use two or more heat pump cycles.

  Further, in the present embodiment, it has been described that the number of revolutions of the circulation pump 38 is controlled. However, duty control that changes the ON time / OFF time may be used.

  As described above, the heat pump hot water supply apparatus according to the present invention can easily store heat in the heat storage unit, and thus can be applied to uses such as heating using the amount of stored heat.

The circuit block diagram of the heat pump hot-water supply apparatus in the 1st form of this invention Flow chart of operation control of the heat pump water heater Configuration diagram of conventional heat pump water heater

DESCRIPTION OF SYMBOLS 20 Heat pump cycle 21 Compressor 22 Hot water supply heat exchanger 22B Incoming water temperature detection means 22C Hot water temperature detection means 23 Expansion valve 24 Evaporator 31 Heat storage unit 38 Circulation pump 51 Target hot water temperature determination means

Claims (5)

A heat pump cycle in which a compressor, a hot water supply heat exchanger, an expansion device, and an evaporator are connected by piping, a heat storage unit that stores heat by circulating a liquid heated using the heat pump cycle, and the hot water supply heat exchange An inlet water temperature detecting means for detecting the incoming water temperature to the water heater, connecting the heat storage unit, the circulation pump, and the heat exchanger for hot water supply with piping, based on the temperature detected by the incoming water temperature detecting means, When the target value of the hot water temperature, which is the temperature at the water outlet of the hot water supply heat exchanger, is determined and the target value is set higher than the incoming water temperature, and the temperature detected by the incoming water temperature detecting means is low, A heat pump hot water supply apparatus characterized in that when the temperature is low and the temperature detected by the incoming water temperature detecting means is high, the target hot water temperature is set high . 2. The heat pump hot water supply apparatus according to claim 1 , wherein an outside air temperature detecting means is provided, and the target hot water temperature is set lower as the temperature detected by the outside air temperature detecting means is lower. Claims provided tapping temperature detection means in the water outlet of the hot water supply heat exchanger, hot water temperature detected by the hot water temperature detecting means so that the target hot water temperature, and controlling the rotational speed of the circulation pump The heat pump hot-water supply apparatus of 1 or 2 . The heat storage unit according to any one of claims 1 to 3 , wherein the heat storage unit includes a latent heat storage material and a liquid circulation path. The heat pump hot water supply apparatus according to any one of claims 1 to 4, wherein the refrigerant used in the heat pump cycle is carbon dioxide and is operated in a state exceeding a critical pressure on a high pressure side.