JP3772883B2 - Operation control method of heat pump device - Google Patents

Description

  The operation control method according to the present invention mitigates sudden pressure fluctuations at the time of changing the compressor operating frequency and expansion valve opening before the defrosting operation, realizes protection of the compressor, and is particularly pressurized above the critical pressure. It is useful as a heat pump water heater and various heat pump devices.

As a prior art, FIG. 11 is a flowchart about the operation before the defrosting operation of the heat pump system. In this system, the electric expansion valve is fully opened after the defrosting condition is established during the heating operation (see, for example, Patent Document 1).
Japanese Patent Publication No. 6-21726

  However, in the case of a system that pressurizes more than the critical pressure, in the conventional system, the full expansion of the electric expansion valve after the defrosting condition is established, and the sudden opening degree change is accompanied by rapid fluctuations in the suction and discharge pressures of the compressor. For this reason, compressor mechanical wear and compressor motor step-out occur, which is a cause of functional loss as a heat pump system.

In order to solve the above-mentioned problem, the operation control method of the heat pump device of the present invention according to claim 1 includes an inverter type compressor, a hot water supply heat exchanger, a decompression device, and a heat source heat exchanger connected in a ring shape by a refrigerant pipe. A heat pump cycle that can adjust the valve opening of the pressure reducing device, a hot water storage tank that stores liquid for hot water supply, a liquid pipe that allows the liquid in the hot water storage tank to circulate through the hot water supply apparatus, and the liquid pipe CO2 in which the liquid in the hot water tank is circulated, and a microcomputer that controls the operating frequency of the inverter compressor and the valve opening of the pressure reducing device, and the refrigerant used is operated at a critical pressure or higher. with it, during defrosting lead time before performing the defrosting operation of the heat exchanger for the heat source, if the operating frequency of the inverter compressor is lowered, the inverter type compressor As the rate of change of refrigerant pressure discharged from becomes less 0.2 MPa / sec, is obtained by said adding a predetermined amount to the valve opening degree of the hot water supply operation last of the pressure reducing device.

The operation control method of the heat pump device of the present invention according to claim 2 is configured by connecting an inverter compressor, a hot water heat exchanger, a pressure reducing device, and a heat source heat exchanger in an annular shape by a refrigerant pipe, and the pressure reducing device. A heat pump cycle that can adjust the valve opening of the water, a hot water storage tank that stores liquid for hot water supply, a liquid pipe that allows the liquid in the hot water storage tank to circulate through the hot water supply device, and the liquid in the hot water tank circulates through the liquid pipe A discharge temperature detecting means for detecting the temperature of the refrigerant discharged from the compressor, and the temperature of the heat source side heat exchanger for determining whether or not the defrosting operation of the heat source side heat exchanger is necessary. a heat source-side heat exchanger temperature detection means for detecting the inverter operating frequency of the compressor, the valve opening before Symbol discharge temperature discharge temperature, which is the output value from the detecting means the decompressor to a predetermined temperature the control degrees Lee black and a computer, in the defrosting preparation period prior to the defrosting operation of the heat exchanger for the heat source, if the operating frequency of the inverter compressor is lowered, the hot water supply operation end of said vacuum The valve opening of the apparatus is held for a certain period of time, and when the operating frequency of the inverter compressor is equal or increased, a predetermined amount is added to the valve opening of the pressure reducing apparatus at the end of the hot water supply operation .

According to a third aspect of the present invention, there is provided a method for controlling the operation of the heat pump apparatus, wherein the number of rotations of the pump is maintained for a predetermined time before the defrosting operation of the heat source heat exchanger .

  Operation control of the heat pump device of the present invention can alleviate sudden pressure fluctuations when changing the compressor operating frequency and expansion valve opening, protect the compressor mechanical wear, etc., and avoid compressor motor step-out.

A first invention comprises an inverter compressor, a hot water supply heat exchanger, a pressure reducing device, a heat source heat exchanger connected in an annular shape by a refrigerant pipe, and a heat pump cycle capable of adjusting the valve opening of the pressure reducing device, A hot water storage tank for storing a hot water supply liquid, a liquid pipe through which the liquid in the hot water storage tank can circulate through the hot water supply apparatus, a pump for circulating the liquid in the hot water storage tank through the liquid pipe, and the inverter compressor And a microcomputer that controls the operating frequency and the valve opening of the decompression device, and the refrigerant used is CO2 that is operated at a critical pressure or higher, and before the defrosting operation of the heat source heat exchanger. during defrosting preparation period, if the operating frequency of the inverter compressor is lowered, the rate of change of refrigerant pressure discharged from the inverter type compressor is less 0.2 MPa / sec In, which was characterized by adding a predetermined amount of the valve opening degree of the hot water supply operation last of the pressure reducing device, hot water supply or driving avoidance and compressor beyond design pressure by preventing an increase in the discharge pressure in the heating operation It is possible to prevent motor overcurrent. In addition, it is possible to prevent the compressor motor from stepping out due to a rapid pressure change before and after the defrosting operation, and to prevent stress of the compressor and the refrigeration cycle parts, thereby extending the life.

A second invention comprises an inverter compressor, a hot water heat exchanger, a pressure reducing device, and a heat source heat exchanger connected in an annular shape by a refrigerant pipe, and a heat pump cycle capable of adjusting the valve opening of the pressure reducing device, A hot water storage tank for storing hot water supply liquid, a liquid pipe through which the liquid in the hot water storage tank can circulate through the hot water supply apparatus, a pump for circulating the liquid in the hot water storage tank through the liquid pipe, and a discharge from the compressor. Discharge temperature detecting means for detecting the temperature of the refrigerant, and heat source side heat exchanger temperature detecting means for detecting the temperature of the heat source side heat exchanger in order to determine the necessity of defrosting operation of the heat source side heat exchanger When the operating frequency of the inverter compressor, and before Symbol discharge temperature control Gosuru microcomputers output value at which the discharge temperature is a valve opening degree of the decompression device to a predetermined temperature from the detection means comprising a heat for the heat source During defrosting preparation period prior to the defrosting operation of the exchanger, when the operation frequency of the inverter compressor is lowered, the valve opening degree of the hot water supply operation last of the pressure reducing device holds a predetermined time, the When the operating frequency of the inverter compressor is equal or increased, a predetermined amount is added to the valve opening of the pressure reducing device at the end of the hot water supply operation , thereby preventing an increase in discharge pressure during hot water supply or heating operation. It is possible to avoid operation exceeding the design pressure and compressor motor overcurrent.

According to a third aspect of the present invention, in particular, before performing the defrosting operation of the heat exchanger for heat source according to the first or second aspect, the hot water sent to the hot water storage tank is maintained by maintaining the rotational speed of the pump for a certain time. Since the temperature is not lowered and the temperature drop of the hot water supply heat exchanger is further suppressed, the heat storage amount is large and the defrosting operation time can be shortened .

(Embodiment 1)
1 and 2 show the heat pump device and the operation control in the first embodiment. FIG. 1 shows an inverter type compressor 11, a hot water supply heat exchanger 12, a pressure reducing device 13, and a heat source heat exchanger 14 connected in a ring shape by a refrigerant pipe 15, and the valve opening of the pressure reducing device 13 is adjusted. Heat pump cycle, a hot water storage tank 16 for storing hot water supply liquid, a liquid pipe 18 through which the liquid in the hot water storage tank can circulate through the hot water supply apparatus, and a pump 17 for circulating the liquid in the hot water storage tank through the liquid pipe. The temperature detection means 31 for detecting the temperature of the refrigerant discharged from the compressor, the temperature detection means 32 for detecting the defrost condition of the heat source side heat exchanger, the operating frequency of the inverter compressor, The microcomputer 30 is configured to control the valve opening degree of the pressure reducing device so that the discharge temperature detecting means has a predetermined temperature. FIG. 2 is an overall configuration diagram of operation control. In the decompression device 13, the valve opening degree is controlled by the decompression device control means 33 in order to control the refrigerant discharge temperature detection means 31 to a desired temperature. Further, the decompression device 13 and the inverter compressor 11 are controlled by the decompression device control means 33 and the compressor operation frequency control means 34 by the defrosting refrigerant temperature detection means 32. FIG. 3 is a flowchart showing the operation of FIGS. 1 and 2, and when the operating frequency of the inverter compressor 11 decreases before the defrosting operation, the valve opening of the decompression device 13 is maintained for a certain period of time. When the operating frequency of the inverter type compressor 11 is equal or increased, the valve opening of the pressure reducing device 13 is opened.

  Next, the operation of this embodiment will be described. 4 and 5 are explanatory diagrams comparing the operation of the compressor and the decompression device and the operation of the discharge refrigerant temperature and the discharge pressure in the respective operation modes in the conventional technique and the present embodiment. According to this, since the operation control of this embodiment maintains the decompression device valve opening degree at the end of the hot water supply operation when the compressor operation frequency is lowered before the defrost operation, the operation control of this embodiment is as in the prior art. Since a sudden pressure drop does not occur, the compressor motor is prevented from stepping out, and a transition to a defrosting operation is possible. Stopping the compressor before the defrosting operation takes time to start again and the heat capacity of the compressor is reduced, so a long-time defrosting operation is required and the hot water supply efficiency deteriorates. It becomes a cause of ice growth on the outdoor unit board and abnormal vibration. Therefore, when the compressor operating frequency is equal or increased before the defrosting operation, the operation control according to the present embodiment adds the predetermined opening degree α to the decompression valve opening degree at the end of the hot water supply operation, thereby reducing the design pressure. An excessive discharge refrigerant pressure rise can be prevented, and a compressor stop due to a compressor motor overcurrent can be prevented.

(Embodiment 2)
6 and 7 show operation control of the heat pump apparatus in the second embodiment. FIG. 6 is an overall configuration diagram of the operation control in the second embodiment. The pump 17 is controlled by the pump rotation speed control means 34 by the defrosting refrigerant temperature detection means 32. FIG. 7 is a flowchart showing the operation in the second embodiment, in which the rotation speed of the pump 17 at the end of the hot water supply operation is held for a certain period of time before performing the defrosting operation.

  Next, the operation of this embodiment will be described. FIG. 8 is an explanatory diagram of the operation of the pump, the compressor, and the pressure reducing device, and the discharge refrigerant temperature and discharge pressure in each operation mode. According to this, since the operation control of this embodiment maintains the pump rotational speed 46 before the defrosting operation, the temperature of the hot water supply heat exchanger is further reduced without reducing the hot water temperature sent to the hot water storage tank 16 as much as possible. In order to suppress the decrease, the heat storage amount is large and the defrosting operation time can be shortened.

(Embodiment 3)
FIG. 9 is a flowchart showing the operation control operation of the heat pump apparatus in the third embodiment. Thus, when the operating frequency of the inverter compressor 11 is lowered before the defrosting operation, the pressure reduction is performed so that the change rate of the refrigerant pressure discharged from the compressor 11 is 0.2 MPa / sec or less. The valve opening of the device 13 is opened by a predetermined amount β.

Next, the operation of this embodiment will be described. FIG. 10 is an explanatory diagram comparing the operation of the compressor and the decompression device and the operation of the discharge refrigerant temperature and the discharge pressure in each operation mode in the first embodiment and the present embodiment. From FIG. 10, when the refrigerant to be used is CO2 that pressurizes above the critical pressure, the operation control of this example is the refrigerant discharged from the compressor 11 when the compressor operating frequency is lowered before the defrosting operation. By opening the valve opening of the pressure reducing device 13 by a predetermined amount β so that the pressure change rate is 0.2 MPa / sec or less, the compressor motor step-out in the defrost preparation 41 is prevented, and immediately after the defrost operation. Therefore, it is possible to reduce the stress on the compressor and the refrigeration cycle parts and extend the life of the parts.

FIG. 3 is a refrigerant circuit diagram of the heat pump device in Embodiment 1 of the present invention. Overall configuration diagram of operation control of heat pump device in Embodiment 1 of the present invention Operation control flowchart of heat pump device in Embodiment 1 of the present invention Operational operation explanatory diagram when compressor operating frequency falls before defrosting operation in Embodiment 1 of the present invention Operational explanatory diagram when compressor operating frequency is equal or increased before defrosting operation in Embodiment 1 of the present invention Operation control overall configuration diagram of the heat pump device in Embodiment 2 of the present invention Operation control flowchart of heat pump device in Embodiment 2 of the present invention Explanatory drawing of operation | movement operation | movement of the heat pump apparatus in Embodiment 2 of this invention. Operation control flowchart of heat pump device in Embodiment 3 of the present invention Explanatory drawing of operation | movement operation | movement of the heat pump apparatus in Embodiment 3 of this invention. Operation control flowchart of heat pump device in the conventional example

Explanation of symbols

11 Compressor 12 Hot-water supply heat exchanger 13 Pressure reducing device (electric expansion valve)
14 Heat source side heat exchanger 15 Refrigerant piping 16 Hot water storage tank 17 Pump (water pump)
DESCRIPTION OF SYMBOLS 18 Liquid piping 19 Fan 20 Fan fan motor 30 Microcomputer 31 Discharge refrigerant | coolant temperature detection means 32 Defrost refrigerant temperature detection means 33 Pressure-reducing-equipment control means 34 Compressor operation frequency control means 35 Pump rotation speed control means

Claims (3)

An inverter compressor, a hot water supply heat exchanger, a pressure reducing device, and a heat source heat exchanger are connected in an annular shape by a refrigerant pipe, and a heat pump cycle capable of adjusting the valve opening of the pressure reducing device, and a liquid for hot water supply A hot water storage tank for storing, a liquid pipe capable of circulating the liquid in the hot water storage tank through the hot water supply device, a pump for circulating the liquid in the hot water storage tank through the liquid pipe, an operating frequency of the inverter compressor, and the pressure reducing device And a microcomputer for controlling the valve opening of the heat source, and the refrigerant used is CO2 operated at a critical pressure or higher, and during the defrost preparation period before performing the defrosting operation of the heat exchanger for heat source , when the operating frequency of the inverter compressor is lowered, as the rate of change of refrigerant pressure discharged from the inverter type compressor is less 0.2 MPa / sec, the hot water supply operation Operation control method of the heat pump apparatus characterized by adding a predetermined amount of the valve opening of the pressure reducing device after. An inverter compressor, a hot water supply heat exchanger, a pressure reducing device, and a heat source heat exchanger are connected in an annular shape by a refrigerant pipe, and a heat pump cycle capable of adjusting the valve opening of the pressure reducing device, and a liquid for hot water supply A hot water storage tank for storing, a liquid pipe through which the liquid in the hot water storage tank can circulate through the hot water supply device, a pump for circulating the liquid in the hot water tank through the liquid pipe, and a temperature of refrigerant discharged from the compressor Discharge temperature detecting means, heat source side heat exchanger temperature detecting means for detecting the temperature of the heat source side heat exchanger to determine whether the defrosting operation of the heat source side heat exchanger is necessary, and the inverter compression operating frequency of the machine, the discharge temperature is the output value from the previous SL discharge temperature detecting means and a micro-computer which control the valve opening degree of the decompression device to a predetermined temperature, for the heat source Defrosting heat exchanger During defrosting preparation period before performing, when the operation frequency of the inverter compressor is lowered, the valve opening degree of the hot water supply operation last of the pressure reducing device holds a predetermined time, the operation of the inverter compressor If the frequency is equal to or rises, the operation control method of the heat pump apparatus characterized by adding a predetermined amount of the valve opening degree of the hot water supply operation last of the pressure reducing device. Before performing the defrosting operation of the heat exchanger for heat source, operation control method of the heat pump apparatus according to claim 1 or 2, wherein the rotational speed of the pump is held a predetermined time.

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