JPS61262553A - Heat pump device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air heat source type heat pump device.

[Conventional technology]

For heating and cooling buildings, we have an outdoor heat exchanger installed on the roof.
A heat pump device is used, which is formed by installing compressors underground and connecting them with long refrigerant piping.

For example, in the heat pump device 7 shown in Figure 2, an outside air heat exchanger unit (A) is installed on the roof of the building, and a compressor unit (B) is installed underground, and the large head difference between them is used as a refrigerant path. They are connected by roads 17 and 18.

Compressor unit B includes a compressor 1, a load-side heat exchanger 2, a receiver 4, a four-way valve 5, and an accumulator 6, and these devices are connected through a refrigerant path.

A solenoid valve 7' is provided between the load side heat exchanger 2 and the receiver 4.
and an expansion valve 8' are arranged in parallel with the check valve 9'.

The outside air side heat exchanger unit) A is equipped with an outside air side heat exchanger 3, and has an expansion valve 8 and a solenoid valve 7 on its inlet side, and a check valve 9.
are deployed in parallel. The expansion valve 8 is a temperature-type automatic expansion valve, and communicates with a pipeline on the outlet side of the outside air side heat exchanger 3 through an external pressure equalizing pipe 11, and a temperature-sensing tube lO provided in the pipeline.
It is communicated with by a communication pipe 15.

The expansion valve 8, which is a thermostatic automatic expansion valve, is shown in detail in FIG. 3. The expansion valve 8 is equipped with a valve 14 and is operated by a diaphragm 12.

The upper chamber of the diaphragm 12 is connected to a temperature sensing tube 1 provided in contact with the outlet pipe of the outside air side heat exchanger 3 through a connecting pipe 15.
It communicates with 0. The temperature sensing cylinder 10 is filled with the same refrigerant used in the heat pump cycle, and is heated by the refrigerant at the temperature TI (the temperature of superheated vapor of the refrigerant) inside the installed pipe line. Almost the same temperature Tl
The saturation pressure pl is introduced into the chamber above the diaphragm 12 through the connecting pipe 15.

A spring 16 is provided in the lower chamber of the diaphragm 12, and the external pressure equalizing pipe 11 communicates with the outlet pipe line of the outside air side heat exchanger 3, and the pressure pz (i.e. steam pressure ) is introduced into the upper chamber of the diaphragm 12.

Therefore, the diaphragm 12 is pushed downward by the force P based on the saturation pressure p+ at the temperature T1 of the superheated steam, the force P of the spring 16 and the force P based on the evaporation pressure p1, and the valve 14 is , P, -P2>P3, and closes when p+ -pg<P3.

Here, P+ Pz is the degree of superheating T'+ Tz (T
z is a value corresponding to the saturation temperature), and according to the above equation, when the degree of superheating becomes large, the valve 14 is opened to supply the refrigerant liquid, and when the degree of superheating is small, the valve 14 is closed to cut off the refrigerant liquid, This operation has the effect of keeping the degree of superheat at a substantially constant value. Since this constant value is determined by the characteristics and initial conditions of the spring 16, the degree of superheat can be adjusted by, for example, fixing a part of the spring 16 using the degree of superheat adjustment screw 13 and changing the spring constant. By keeping this degree of superheat at a predetermined value, it is possible to prevent liquid leakage from occurring during normal operation.

The relationship between this pressure and the degree of superheat is shown in Figure 4.The saturated vapor pressure line of the refrigerant is upright (steep slope) in the high temperature region and flat (gentle slope) in the low temperature region. As shown in the characteristic curve of pressure and temperature in the saturated state of the refrigerant in Figure 4, the same pressure difference P.

On the other hand, the temperature difference (degree of superheating SH) becomes smaller as the pressure becomes higher. That is, when the evaporation pressure has not decreased and still shows a relatively high value Pi' as at the time of starting the heat pump cycle, the same pressure difference P is maintained.

(The force of the spring 16 is constant) The degree of superheating SH is smaller than the degree of superheating SH when the evaporation pressure decreases to P. This indicates that the temperature is close to the outlet of the outside air side heat exchanger 3.

In addition, when the temperature and pressure of the internal refrigerant change in the outlet pipe line of the outside air side heat exchanger 3, the pressure p2 is immediately transmitted by the external pressure equalizing pipe 11, but the temperature is transferred to the temperature sensing tube 10.
Since the response of is poor, the saturation pressure pl corresponding to temperature change
changes are transmitted with a delay. Therefore, when the pressure and temperature of the refrigerant decreases after startup, the force P pushing the diaphragm 12 upward immediately decreases due to the decrease in pressure pt.
Even if the temperature T decreases, the temperature of the refrigerant in the temperature sensing tube 10 does not drop suddenly, and the saturation pressure pl decreases with a delay, so the force P pushing the diaphragm 12 downward decreases immediately after startup. Decreases without delay.

Therefore, immediately after startup, the valve 14 closes later than it should, so the full opening operation takes longer than necessary.

[Problem that the invention seeks to solve]

At startup, the compressor 1 is started and the solenoid valve 7 is opened to supply refrigerant, but when the pressure of the refrigerant is high, such as at startup, the liquid refrigerant approaches the outlet of the outside air side heat exchanger 3. Due to the temperature-type automatic expansion valve and the characteristics of the temperature-type automatic expansion valve, the refrigerant amount control cannot be done in time, leading to an excessive supply of refrigerant liquid, and the liquid refrigerant exits the outside air side heat exchanger 3 and enters the pipe line 18 via the accumulator 6. A large amount of liquid may flow into the compressor 1, and in order to prevent this, the accumulator 6 needs to have an excessively large capacity.

In particular, in a separate type heat pump in which the compressor unit B and the outside air side heat exchanger unit A are installed underground and on the roof, the pipes 17 and 18 are long, and the pipe 17 in particular is used for the summer refrigeration cycle. Since a large pipe is used to allow the refrigerant liquid to flow down naturally during operation, the amount of refrigerant liquid accommodated in the pipe line 17 is large. In the winter, this large amount of refrigerant liquid stored in the pipe 17 up to the inlet of the expansion valve 8 is supplied at the time of startup before waiting for startup.
The excessive supply amount due to the delay in refrigerant amount control becomes extremely large, and the problem of liquid back up becomes even more serious.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat pump device that can solve the above-mentioned problems of the conventional heat pump, prevent liquid back-up during startup of the heat pump, and suppress an increase in the capacity of the achievator.

[Means for solving problems]

The present invention, as a means for solving the above problems,
In a heat pump device comprising a compressor, a load side heat exchanger, an outside air side heat exchanger, an expansion valve, and a refrigerant path connecting these devices, a plurality of on-off valves for supplying refrigerant liquid to the outside air side heat exchanger are provided. It is an object of the present invention to provide a heat pump device characterized in that the heat pump device is arranged in parallel and the flow rate is changed from a small flow rate to a large flow rate by operating the opening and closing operations of the plurality of on-off valves at the time of startup.

〔Example〕

Embodiments of the present invention will be described using the drawings.

In FIG. 1, parts having the same reference numerals as in FIG. 2 have similar structures and functions.

On the inlet side of the expansion valve 8 during the heating cycle, a large capacity solenoid valve 22 and a small capacity solenoid valve 23 are arranged in parallel as a plurality of on-off valves. 20 is a control device, and 21 is a motor.

At startup, the motor 21 is started by a signal from the control device 20, first the small capacity electromagnetic valve 23 is opened, and then, after a predetermined time interval, the large capacity electromagnetic valve 22 is opened to ensure steady capacity operation.

In this way, by suppressing the flow rate to a small flow rate immediately after startup, the initial overshoot can be suppressed, the liquid bank amount can be suppressed to a small amount, and the capacity of the accumulator 6 can be made small. .

The number of solenoid valves may be three or more, and they may have the same capacity.

Although the case where a thermostatic automatic expansion valve is used has been described above, liquid backflow can be prevented even when other systems are used if they are used in conditions where liquid backflow is likely to occur.

〔Effect of the invention〕

According to the present invention, it is possible to provide a heat pump device that prevents liquid back up in an air source heat pump and suppresses an increase in the capacity of an accumulator, and has extremely great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram of an embodiment of the present invention, FIG. 2 is a flow diagram of a conventional example, and FIG. 3 is a flow diagram of an example of a thermostatic automatic expansion valve.
FIG. 4 is a graph showing the relationship between pressure and temperature when the refrigerant is saturated. DESCRIPTION OF SYMBOLS 1...Compressor, 2...Load side heat exchanger, 3...Outside air side heat exchanger, 4...Receiver, 5...Four-way valve, 6
...Akiemureta, 7,7゛...Solenoid valve, 8.8
'...Expansion valve, 9.9'...Check valve, 10...Temperature sensing cylinder, 11...External pressure equalization pipe, 12...Diaphragm 13...Superheat degree adjustment screw, 14 ...Valve, 15...
・Communication pipe, 16... Spring, 17.18... Conduit, 2
0...Control device, 21...Motor, 22...Large capacity solenoid valve, 23...Small capacity solenoid valve. Patent applicant Shimizu Corporation Patent applicant Co., Ltd.
Ebara Corporation Representative Patent Attorney Masayuki Takagi Representative Patent Attorney Pharmacist
Minoru Patent Attorney Yori 1) Takatsugu Department Figure 2 Temperature

Claims (1)

[Claims] 1. In a heat pump device comprising a compressor, a load side heat exchanger, an outside air side heat exchanger, an expansion valve, and a refrigerant path connecting these devices, a plurality of on-off valves for supplying refrigerant liquid to the outside air side heat exchanger are provided. A heat pump device, characterized in that the heat pump device is arranged in parallel, and the flow rate is changed from a small flow rate to a large flow rate by operating the opening and closing operations of the plurality of on-off valves at the time of startup.