JPS62225865A - Heat pump type air conditioner - 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 [Objective of the Invention] (Industrial Field of Application) The present invention relates to a heat pump type air-conditioning system having one outdoor unit and a plurality of indoor units. Used for air conditioning.

(Prior art) The prior art related to the present invention is Japanese Patent Publication No. 52-1657
There is one described in Publication No. 7.

This conventional technology will be explained with reference to FIG. 3. During cooling, high-temperature, high-pressure refrigerant gas discharged from the compressor 32 enters the outdoor heat exchanger 34 and radiates heat to the outside air, and the condensed and liquefied refrigerant passes through the liquid branch point 42. After that, the capillary tubes 39a and 3 in the indoor units 36a and 36b configured in parallel are
The pressure is reduced at 9b, the indoor heat exchangers 37a and 37b absorb heat from the indoor air and evaporate, and the branch point 43 and four-way valve 33
The air flows in this order and is sucked into the compressor 32.

On the other hand, during heating operation, the high-temperature, high-pressure refrigerant gas discharged from the compressor 32 passes through the four-way valve 33, the piping 41, and the branch point 43, and is blown by the indoor heat exchangers 37a and 37b. The indoor air sent by 38b is superheated and condensed into liquid. Then, the pressure is reduced in the capillary tubes 39a, 39b, and the branch pipes 40a, 40b,
It flows in the order of the branch point 42 , absorbs heat and evaporates in the outdoor heat exchanger 34 , and is sucked into the compressor 32 .

(Problem to be solved by the invention) However, in this prior art, during heating operation, if the air volumes of the motorized fans of the indoor units are different from each other, or if there is a difference in the air temperature sucked by the fans, the capillary tube A large difference occurs in the degree of condensation and temperature of the refrigerant flowing into the refrigerant. To explain this using the pressure enthalpy diagram shown in FIG. 4, Pe is the condensation pressure and Pc is the evaporation pressure. A is the state before the compressor, B is the state at the condenser inlet, C is the state of the capillary tube, and D is the state before the evaporator. Here, if there is a difference in indoor temperature or if the fan air volume is different, the 0 point changes to points Ca and Cb, respectively. Regarding cb, the refrigerant here is not completely condensed, does not achieve an appropriate degree of supercooling, and does not effectively absorb heat from the outside air in the evaporator, reducing the coefficient of performance of the device. Also Ca
In this case, the degree of supercooling becomes excessive, and the refrigerant flow rate becomes relatively insufficient for indoor heating requirements.

The technical objective of the present invention is to solve this problem and improve the coefficient of performance during heating.

[Structure of the invention]

(Means for solving the problem) The technical means taken to solve the above problem is to provide an outdoor unit with a compressor, a pressure sensor that detects the discharge pressure, and a pressure sensor that detects the pressure detected by the pressure sensor. A controller for controlling the rotation speed of the compressor to keep it constant and a prime mover are provided, and the indoor unit is provided with an expansion valve for cooling operation disposed in the liquid piping, and an expansion valve disposed in parallel with the expansion valve. A check valve and a temperature-sensitive flow control valve are provided.

(Function) According to this, during heating operation, the pressure inside the indoor heat exchanger, that is, the condensing pressure, is maintained at the set value regardless of the fan motor rotation speed or the indoor temperature, and furthermore, by the function of temperature-sensitive flow rate control, By maintaining the temperature of the refrigerant liquid passing through this at a preset temperature, the coefficient of performance of the heat pump cycle can always be maintained at a high value.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 and 2.

1 is an outdoor unit, and a compressor 2. A pressure sensor 3 for detecting high temperature and high pressure refrigerant gas discharged from the compressor 2.
5. A prime mover that changes the rotation speed of the compressor 2 using a controller 4. Four-way valve6. Outdoor heat exchanger7. A fan with a motor for blowing air to the outdoor exchanger 7 8. Expansion valve9. Check valve 1
Consists of 0.

11a and llb are indoor units, and indoor heat exchanger 1
2a, 12b, motorized fans 13a, 13b for blowing air to the indoor heat exchangers 12a, 12b, and expansion valve 1.
4a, 14b, expansion valves 14a, 14b, temperature-sensitive flow control valves 20a, 20b, and check valves 15a, 15b.

The outdoor unit 1 and the indoor units) 11a and 11b are connected through pipes 16.17 and branch pipes 16a, 16b, 17a, and 17b branched at intermediate branch points 18.19.

The temperature-sensitive flow control valves 20a and 20b form an inlet 21 for the refrigerant liquid, as shown in FIG. It is composed of a valve stem 25 that changes the lifting height according to changes in the volume of the wax 23, and a spring 26 that prevents the valve stem 25 from rattling.

When performing cooling operation with the above configuration, the high temperature and high pressure gas discharged from the compressor 2 radiates heat to the outside air through the four-way valve 6 and the outdoor heat exchanger 7, and is condensed and liquefied.

The condensed and liquefied refrigerant passes through the check valve 10 and reaches the branch point 18.
The branch pipe 1 is distributed to each indoor unit lla and llb.
6a, 16b, the pressure is reduced by expansion valves 14a, 14b, and the indoor heat exchanger 12a.

At 12b, it absorbs heat from the indoor air and becomes a gas, cooling the room.
．． It is sucked into the compressor 2 through the four-way valve 6.

Here, the suction pressure of the compressor 2 changes depending on the fan air volume and cooling load of each indoor unit lla and Ilb, but the pressure sensor 3'' detects the change in suction pressure, and the controller 4 controls the rotation speed of the prime mover 5, that is, the rotation speed of the prime mover 5. The rotational speed of the compressor 2 is controlled to maintain the suction pressure at the set value.This causes the indoor heat exchanger 12a.

Since the evaporation temperature at 12b can be kept at the set value, the cold air blowout temperature can also be kept almost constant. At this time, the refrigerant does not flow through the temperature-sensitive flow control valves 20a, 20b due to the action of the check valves 15a, 15b installed in series therewith.

On the other hand, when performing heating operation, the high-temperature, high-pressure refrigerant gas discharged from the compressor 2 enters the branch point 19 from the four-way valve 6, passes through the branch pipes 17a and 17b, and radiates heat to the indoor air at the indoor heat exchangers 12a and 12b. It condenses and becomes a cooling liquid. After this,
Temperature-sensitive flow control valves 20a, 20b, check valves 15a, 15b
It passes through branch pipes 16a and 16b, joins at a branch point 18, is depressurized by an expansion valve 9, flows into an outdoor heat exchanger 7, absorbs heat from the outside air, evaporates, passes through a four-way valve 6, and then flows into a compressor 2. is inhaled.

The temperature-sensitive flow rate control valves 20a, 20b restrict the passage of the refrigerant higher than the set liquid temperature, and the indoor heat exchangers 12a, 1
After being liquefied in step 2b, the liquid level in the heat exchangers 12a, 12b is raised so that the liquid temperature drops to the set temperature, and when the refrigerant lower than the set value passes through, the inlet is widened and the heat exchanger 12a,
Lower the liquid level in 12b to reduce cooling with liquid,
As a result, it works to keep the temperature of the liquid passing through each part constant.

Here, the pressure (condensing pressure) of the indoor heat exchangers 12a and 12b is maintained at a set value by controlling the rotation speed of the prime mover 5, that is, the rotation speed of the compressor 2, using the discharge pressure sensor 3 and the controller 4. As a result, the temperature-sensitive flow control valve 2
The so-called degree of supercooling of the refrigerant passing through 0a and 20b can be kept constant.

〔Effect of the invention〕

As mentioned above, during heating, the condensing pressure is kept constant by controlling the compressor rotation speed, and the temperature of the refrigerant condensate is kept constant by the temperature-sensitive flow rate control valve. In addition to always maintaining a high coefficient of performance, the temperature of the air blown from the indoor unit can be kept almost constant.

Furthermore, when one indoor unit stops operating, the gaseous refrigerant circulates through this unit as well, but the heat dissipation from this unit is small, and the gaseous refrigerant accumulates in the idle indoor unit, causing the refrigerant to become liquid. Since the refrigerant does not accumulate, heating operation can be performed without the amount of circulating refrigerant becoming insufficient or excessive.

[Brief explanation of drawings]

Fig. 1 is a refrigerant circuit diagram showing one embodiment of the device of the present invention;
The figure is a sectional view of a temperature-sensitive flow control valve, FIG. 3 is a refrigerant circuit diagram of a conventional device, and FIG. 4 is a pressure enthalpy diagram. 1... Outdoor unit, 2... Compressor, 3... Pressure sensor, 4... Controller, 5... Prime mover, l
la, llb...indoor unit. 13a, 13b --- expansion valve, 14a, 14b...
・Check valve, 20a, 20b...temperature-sensitive flow control valve

Claims (1)

[Claims] In a heat pump air conditioning system having one outdoor unit and a plurality of indoor units, the outdoor unit includes a compressor, a pressure sensor that detects discharge pressure, and a pressure sensor that maintains the pressure detected by the pressure sensor constant. The indoor unit has an expansion valve for cooling operation disposed in the liquid piping, and an expansion valve disposed in parallel with the expansion valve. A heat pump type air-conditioning device having a check valve and a temperature-sensitive flow control valve.