JPH0531064B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a separate heat pump installed in a high-rise building.

(Prior Art) Conventionally, most large heat pumps for high-rise buildings have been of the separate type (Japanese Patent Publication No. 61-5062, Publication of Utility Model Publication No. 55-24524), and Fig. 2 shows this separate type heat pump. The state during heating operation is shown.

That is, as is well known, the heat pump in this state includes a compressor 11, a water heat exchanger 12 that functions as a condenser, a liquid receiver 13, an electromagnetic on-off valve 14, an expansion valve 15, and an air heat exchanger that functions as an evaporator. A closed loop of refrigerant containing 16 is formed. Further, in the illustrated example, the compressor 11 is of a screw type using a screw rotor, and includes a slide valve 18 for capacity control driven by a hydraulic cylinder 17, and is driven by a motor 19.

Two pipes 20 and 21 are connected to the water heat exchanger 12. Chilled water is led from one pipe 20, and inside the vessel, between this led water and the refrigerant in the pipe 22. Heat exchange is performed, and hot water used for heating is sent out from the other pipe 21.

The expansion valve 15 is connected to a pipe line 23 on the suction side of the compressor 11.
A pressure signal is inputted through a pipe line 24 branched from the pipe line 23, and a temperature signal is inputted through a temperature sensing tube 25 provided on the wall of the pipe line 23. The opening degree of the expansion valve 15 is controlled so that the degree of superheating of the expansion valve 15 is constant.

On the other hand, during the illustrated heating transition, a temperature sensor 26 is installed in a hot water pipe 21 connected to a water heat exchanger 12 functioning as a condenser to detect the temperature.
The discharge gas flow rate of the compressor 11 is controlled by adjusting the opening degree of the slide valve based on the detected temperature.

In the figure, the rectangular part indicated by the chain double-dashed line is a high-rise building, and the air heat exchanger 16 is installed on the roof R of the building, and the other parts are installed in the basement B. The distance between them, that is, the height difference, can reach several tens of meters or more than 100 meters. Then, the refrigerant whose pressure is reduced from the high-pressure liquid at the expansion valve 15 is blown into the vertical pipe line 27 from the basement B to the rooftop R, and is sent to the air heat exchanger.

(Problem to be Solved by the Invention) In the conventional device described above, the opening and closing of the expansion valve 15, that is, the refrigerant flow rate here, is controlled so that the degree of superheating on the outlet side of the air heat exchanger 16 is kept constant. On the other hand, the gas flow rate in the compressor 11 is the same as that in the water heat exchanger 1.
It is controlled based on the hot water temperature in the pipe line 21 from 2.

However, since there is a time lag between the state on the outlet side of the air heat exchanger 16 and the state of the suction flow rate of the compressor controlled by the hot water temperature, the compressor 11
There is a problem that an imbalance occurs between the flow rate of the suction gas at the pump and the amount of liquid supplied from the expansion valve 15, and the refrigerant that cannot be completely evaporated in the air heat exchanger 16 flows back to the compressor 11, causing damage to the compressor 11. It is occurring.

Additionally, if the degree of superheating on the outlet side of the air heat exchanger 16 increases while the device is stopped, the expansion valve 15 will be fully opened. The refrigerant liquid in the container 13 is sent to the air heat exchanger 16 all at once and in large quantities.
However, since the flow rate of the suction gas of the compressor 11 and the amount of evaporation in the air heat exchanger 16 are not maximized, the flow rate of the refrigerant in the vertical pipe 27 is insufficient.
Refrigerant liquid accumulates, and as mentioned above, damage to the compressor due to the liquid backlog is a problem.

The present invention has been made in view of these conventional problems, and aims to provide a separate type heat pump that can prevent liquid backflow to the compressor.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a separate heat pump that forms a closed loop of refrigerant including a compressor, a condenser, a liquid receiver, an expansion valve, and an evaporator. A supply unit that calculates the required opening degree of the expansion valve based on detection signals from a pressure sensor and a temperature sensor that are installed in the suction side pipe line of the compressor so as to be able to detect pressure or temperature, and outputs an opening degree signal. The required opening of the expansion valve is calculated based on the detection signal from the liquid controller and the opening sensor provided in the driving part of the slide valve for compressor capacity control to detect the opening of the slide valve. a linearizer that outputs a degree signal, a time function generator that receives a start signal for the compressor, calculates a required opening degree of the expansion valve corresponding to the elapsed time after startup, and outputs an opening signal; An expansion valve control section is provided, which includes a liquid controller, a linearizer, and a low selector that outputs the smallest opening degree signal from the time function generator to the expansion valve as a control signal.

(Function) By forming the structure as described above, the flow rate of the suction gas of the compressor and the flow rate of the refrigerant liquid at the expansion valve are balanced, including when the device is started, and the refrigerant liquid at the outlet of the expansion valve is evaporated. This maintains a flow rate that allows continuous and stable supply of liquid to the evaporator, stabilizes evaporation in the evaporator, and eliminates the liquid back phenomenon.

(Example) Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows the state of the separate heat pump according to the present invention during heating operation, and the heat pump shown in FIG. 2 is substantially the same except for the control unit for the expansion valve, and the parts correspond to each other. are given the same numbers and their explanations will be omitted.

As shown in the figure, the control unit 1 of this device is a compressor 1.
A pressure sensor 2 and a temperature sensor 3 are provided in the suction side pipe line 23 of the pump 1 so as to be able to detect pressure or temperature, and the detection signal from each sensor is inputted to the liquid supply controller 4. be. This liquid supply controller 4 calculates the degree of superheating on the outlet side based on the outlet pressure and temperature of the air heat exchanger 16 as an evaporator detected by each of the sensors,
This calculation result is subjected to PID calculation to calculate the required opening degree of the expansion valve 15 corresponding to the above-mentioned degree of superheating, and this opening degree signal is output.

Furthermore, the compressor 11
The linearizer 6 calculates the suction capacity of the expansion valve 15, calculates the required opening degree O of the expansion valve 15 corresponding to this value, and outputs this opening degree signal. The expansion valve 15 corresponds to the flow rate on the suction side of the compressor 11 with respect to the elapsed time t.
Calculate the required opening degree O from a preset function,
A time function generator 7 is provided to output this opening degree signal. The graphs shown next to the linearizer 6 and time function generator 7 in FIG. 1 illustrate the relationship between the required opening degree O of the expansion valve 15 with respect to the above-mentioned suction capacity and the required opening degree O of the expansion valve 15 with respect to the above-mentioned elapsed time t, respectively. This is what I did.

Furthermore, upon receiving opening signals from the liquid supply controller 4, linearizer 6, and time function generator 7,
A low selector 8 is provided for adjusting the opening degree of the expansion valve 15 with respect to the smallest one of these valves 15.

With this configuration, when the compressor 11 is started, the output from the liquid supply controller 4 is at its maximum, but since the output from the time function generator 7 gradually increases, this output is used as the control signal. The expansion valve 15 is designed to gradually open.

In addition, in normal operation, the output from the time function generator 7 is at its maximum, so the opening of the expansion valve 15 is determined by the smaller of the outputs from the liquid supply controller 4 and the linearizer 6. controlled. For example, when the temperature of hot water from the water heat exchanger 12 rises above a specified value and the suction capacity of the compressor 11 becomes smaller, the output from the linearizer 6 becomes smaller than the output from the liquid supply controller 4. The opening degree of the expansion valve 15 is controlled by this output. Through such control, the air heat exchanger 1
The refrigerant liquid is not sent from the expansion valve 15 in excess of the amount of evaporation at step 6, thereby eliminating the liquid back phenomenon.

In addition, in the above embodiment, only the state during heating operation is shown in order to avoid complication of pipe lines in the drawings, but in reality, heat pumps are operated in cooling mode using pipe switching valves, as has been widely done in this technical field. It is now possible to set it to the operating state.
In this state during cooling operation, a closed loop returns from the compressor 11 to the air heat exchanger 16, liquid receiver 13, on-off valve 14, expansion valve 15, and water heat exchanger 12 in this order to the compressor 11. The temperature sensor 26 detects the temperature of the cold water on the outlet side of the water heat exchanger 12, and the slide valve 1 is activated based on this detection signal.
8, the air heat exchanger 16 functions as a condenser, and the water heat exchanger 12 functions as an evaporator. The rest is the same as in the case of heating operation.

(Effects of the Invention) As is clear from the above description, according to the present invention, in a separate heat pump forming a closed loop of refrigerant including a compressor, a condenser, a liquid receiver, an expansion valve, and an evaporator, the above-mentioned A liquid supply that calculates the required opening degree of the expansion valve based on detection signals from a pressure sensor and a temperature sensor provided in the suction side pipe line of the compressor so as to be able to detect pressure or temperature, and outputs an opening degree signal. The required opening of the expansion valve is calculated based on the detection signal from the controller and the opening sensor installed in the drive section of the slide valve for compressor capacity control to detect the opening of the slide valve. a linearizer that outputs a signal; a time function generator that receives the start signal of the compressor, calculates a required opening of the expansion valve corresponding to the elapsed time after startup, and outputs an opening signal; and a time function generator that outputs an opening signal. controller, linearizer,
An expansion valve control section including a low selector that outputs the smallest of the opening degree signals from the time function generator as a control signal to the expansion valve is provided.

Therefore, the flow rate of the suction gas of the compressor and the flow rate of the refrigerant liquid at the expansion valve are balanced, and the flow rate of the refrigerant liquid at the outlet side of the expansion valve is set to a size that allows continuous and stable refrigerant supply to the evaporator. This has the effect of stabilizing evaporation, eliminating the liquid back phenomenon, and preventing damage to the compressor.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing only the state of a heat pump according to the present invention during heating operation, and FIG. 2 is an overall configuration diagram showing only the state of a conventional heat pump during heating operation. 1... Control unit, 2... Pressure sensor, 3... Temperature sensor, 4... Liquid supply controller, 5... Opening sensor, 6... Linearizer, 7... Time function generator, 8... Low selector , 11...compressor, 12
... Water heat exchanger, 13 ... Liquid receiver, 14 ... Opening/closing valve, 15 ... Expansion valve, 16 ... Air heat exchanger, 17
...Hydraulic cylinder, 18...Slide valve, 19...
...Motor, 23...Pipe line.

Claims (1)

[Claims] 1 In a separate type heat pump that forms a closed loop of refrigerant including a compressor, a condenser, a liquid receiver, an expansion valve, and an evaporator, a pressure sensor installed in the suction side pipe of the compressor to be able to detect pressure or temperature. , a liquid supply controller that calculates the required opening of the expansion valve based on the detection signal from the temperature sensor and outputs an opening signal, and a slide valve opening provided in the drive section of the slide valve for compressor capacity control. A linearizer that calculates the required opening of the expansion valve based on a detection signal from an opening sensor installed to detect the degree of opening, and outputs an opening signal; a time function generator that calculates the required opening of the expansion valve corresponding to the elapsed time and outputs an opening signal; the liquid supply controller; the linearizer;
A separate type heat pump comprising an expansion valve control section comprising a low selector that outputs the smallest of the opening degree signals from the time function generator as a control signal to the expansion valve.