JP3134459B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner in which an outdoor unit exchanger and an indoor heat exchanger are connected by refrigerant pipes.

[0002]

2. Description of the Related Art FIG.
FIG. 3 is a configuration diagram illustrating a conventional air conditioner disclosed in Japanese Patent Publication No. 3 (JP-A) No. 3-2003. In the figure, 1 is a compressor that compresses and discharges refrigerant.
2 is a four-way valve for switching the refrigerant passage to the compressor 1 and the destination of the compressed refrigerant, 3 is an outdoor heat exchanger, 4 is a pressure reducing valve, 5 is an indoor heat exchanger, 6 is a liquid storage device, and 8 is a compressor. 1, a refrigerant circuit comprising a four-way valve 2, an outdoor heat exchanger 3, a pressure reducing valve 4, an indoor heat exchanger 5, a liquid storage device 6, and a refrigerant pipe 7 sequentially connected to the compressor 1, and 9, 10 represent outdoor heat exchange, respectively. A temperature detector 11 which is installed on the refrigerant pipe 7 at the center and the outlet of the detector 3 and detects the temperature of the refrigerant pipe 7 at that position; and 11 converts the temperature signal detected by the temperature detectors 9 and 10 into digital temperature data. The A / D converter 12 compares the digital temperature detection signal output from the A / D converter 11 with a preset reference value and calculates the same, thereby obtaining the optimum opening of the pressure reducing valve 4. And 13, a valve opening control means for controlling the optimum opening of the pressure reducing valve 4. .

A conventional air conditioner is configured as described above. When the compressor 1 is driven by turning on a power switch, a high-temperature and high-pressure refrigerant gas is discharged from the compressor 1.
Then, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 is supplied to the outdoor heat exchanger 3 via the four-way valve 2, and exchanges heat with outdoor air to become a high-pressure liquid refrigerant for condensation. The high-pressure liquid refrigerant condensed in this way is depressurized by the pressure reducing valve 4 and then exchanges heat with indoor air when passing through the indoor heat exchanger 5 to become a low-pressure gas refrigerant. The low-pressure gas refrigerant is supplied to the four-way valve 2 and the reservoir 6
, Is compressed again by the compressor 1, and is discharged as a high-temperature and high-pressure refrigerant gas to constitute a refrigeration cycle, thereby achieving the function as an air conditioner. Here, the temperature detectors 9 and 10 installed on the refrigerant pipe 7 at the center and at the outlet of the outdoor heat exchanger 3 serving as a condenser are used to determine the saturation temperature at which high-temperature and high-pressure refrigerant gas is condensed and the saturation temperature of the outdoor heat exchanger 3. Detect outlet temperature. The detection signal is supplied to the A / D converter 11. The A / D converter 11 converts the analog value temperature detection signal supplied from the temperature detectors 9 and 10 into a digital signal and then supplies the digital signal to the comparison operation unit 12. The comparison operation unit 12 compares the digital value supplied from the A / D conversion unit 11 with the reference value of the temperature detection signal and performs an operation to obtain the optimum opening of the pressure reducing valve 4. Then, the valve opening control means 13 controls the valve opening of the pressure reducing valve 4 in accordance with the calculation output of the comparison calculation unit 12, so that the outdoor heat exchanger 3, which is a condenser detected by the temperature detectors 9, 10. Is controlled such that the degree of subcooling (subcooling) of the refrigerant at the outlet of the above becomes a predetermined value.

That is, when the temperature of outdoor air rises,
The condensation capacity of the outdoor heat exchanger 3 decreases, the condensation temperature rises, and the degree of supercooling of the liquid refrigerant at the outlet of the outdoor heat exchanger 3 serving as a condenser decreases. For this reason, the opening degree of the pressure reducing valve 4 is widened so as to make the degree of subcooling constant, and the circulating refrigerant flow rate during the cooling operation is increased. As a result, even if the temperature of the outdoor air rises or falls, the comparison operation unit 12 and the valve opening unit 12 open the valve so that the degree of supercooling detected by the temperature detectors 9 and 10 is constant so that the flow rate of the circulating refrigerant is appropriate. The degree of opening of the pressure reducing valve 4 is controlled by the degree control means 13.

[0005]

In the conventional air conditioner as described above, the pressure reducing valve 4 is controlled to a pressure reducing action suitable for the respective operating states of cooling and heating. Such control is provided with a capacity control function for changing the refrigerant flow rate. For example, when the inverter-controlled compressor 1 is mounted, fine-grained refrigerant control is possible. However, when the compressor 1 without the capacity control function, for example, without the inverter control is mounted, there is a problem that the refrigerant control is insufficient only by adjusting the opening degree of the pressure reducing valve 4. Further, the electrically operated pressure reducing valve 4 itself is expensive, and the air conditioner having the above-described pressure reducing valve 4 control includes complicated components such as temperature detectors 9 and 10, an A / D converter 11, and a comparator 12. However, there is a problem that the production cost is increased because a complicated system is required.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. A compressor without a capacity control function is mounted, and required refrigerant control can be performed by adjusting the opening of a pressure reducing valve in a cooling overload condition. The purpose is to obtain an air conditioner that can be used.

[0007]

In an air conditioner according to the present invention, a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducing capillary, an indoor heat exchanger, and a liquid storage device are sequentially connected by refrigerant piping. A refrigerant circuit and a depressurizing capillary are formed, and both the constant-pressure depressurizing capillary arranged in series with each other and provided near the outdoor heat exchanger, and the heating-time depressurizing capillary provided near the indoor heat exchanger are both provided. and a capillary tube for heating and cooling during normal vacuum provided between the both end provided for the heating and cooling during normal depressurizing capillary of the refrigerant circuit
Connected between the four-way valve and the outdoor heat exchanger, the other end is a refrigerant circuit
Capillary tubes for normal and decompressing heating and cooling
The pressure to operate a bypass circuit connected between a throttle mechanism arranged in a bypass circuit of this, the sliding valve sliding in response disposed bypass circuit pressure chamber outside the heat exchanger inlet An on-off valve is provided.

[0008]

In the air conditioner constructed as described above, when the pressure at the entrance of the outdoor heat exchanger exceeds the set value during the cooling operation, the bypass circuit provided for the heating / cooling normal pressure reducing capillary is opened. As a result, the decompression effect is reduced.

[0009]

[Embodiment 1] 1 to 4 show an embodiment of the present invention.
1 is a compressor that compresses and discharges the refrigerant, 2 is a four-way valve that switches the refrigerant inlet to the compressor 1 and the destination of the compressed refrigerant, 3
Is an outdoor heat exchanger, 41 is a depressurizing capillary, which is arranged in series with each other and is a constant depressurizing capillary 42 provided near the outdoor heat exchanger 3 and a depressurizing capillary provided near the indoor heat exchanger 5. Both of the capillaries 43 are provided, as well as a heating / cooling normal-time depressurization capillary 44 provided between the both. 5 is an indoor heat exchanger, 6 is a reservoir, 8 is a compressor 1,
A refrigerant circuit comprising a four-way valve 2, an outdoor heat exchanger 3, a depressurizing capillary 41, an indoor heat exchanger 5, a liquid storage 6, and a refrigerant pipe 7 to which the compressor 1 is sequentially connected constitutes a heat pump type refrigerant circuit. ing. Reference numeral 14 denotes a check valve provided in a bypass circuit formed for the heating-time pressure reducing capillary 43, and reference numeral 15 denotes a bypass circuit provided for the heating / cooling normal-time pressure reducing capillary 44, as shown in FIG. One end of the refrigerant circuit 8
Is connected between the two-way valve 2 and the outdoor heat exchanger 3, and the other end is connected to a refrigerant circuit.
Route 8 heating / cooling normal depressurization capillary tube 44 and heating depressurization
Connected between the capillary tubes 43 . Reference numeral 16 denotes a pressure opening / closing valve which is provided in the bypass circuit 15 and forms a throttle mechanism 17. A valve inlet 20 and an on-off valve outlet 21 are provided,
In the space inside the base body 18, blocking portions 22 and 23 are formed apart from each other, and a sliding valve 24 that slides therebetween is arranged. Further, the sliding valve 24 is provided with a communication hole 25 corresponding to the opening / closing valve inlet 20 and the opening / closing valve outlet 21, and the pressure receiving port 19 side of the sliding valve 24 is formed from an elastic body into a space 26 with the blocking portion 22. Resistor piece 27 is disposed. Further, an atmosphere opening hole 28 is provided on a side wall of the space 26 of the base 18.

In the air conditioner constructed as described above, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 during normal cooling is supplied to the outdoor heat exchanger 3 through the four-way valve 2 and the outdoor air Then, it is cooled by heat exchange, condensed, and becomes a supercooled liquid refrigerant with high pressure. The high-pressure liquid refrigerant condensed in this way is constantly depressurized by the pressure-reducing capillary 42 and the heating / cooling normal-time pressure-reducing capillary 44, and then returned to the check valve 1.
The heat exchanger 5 passes through the indoor heat exchanger 5 and exchanges heat with the indoor air, thereby being heated and evaporated at a low pressure to become a gas refrigerant. Then, the cycle of returning the low-pressure gas refrigerant to the compressor 1 through the four-way valve 2 and the liquid storage device 6 is repeated. At the time of heating, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2 and exchanges heat with the indoor heat exchanger 5 operating as a condenser to become a high-pressure supercooled liquid refrigerant. Further, the pressure is reduced by the heating pressure reducing capillary 43, the heating / cooling normal pressure reducing capillary 44, and the constant pressure reducing capillary 42, and heat is exchanged in the outdoor heat exchanger 3 which operates as an evaporator.
Evaporates to a gas refrigerant. Then, the cycle of returning the gas refrigerant to the compressor 1 through the four-way valve 2 and the liquid storage device 6 is repeated.

FIG. 4 shows the refrigerant pressure P (kg / kg) on the vertical axis.
FIG. 2 is a Mollier diagram with enthalpy (kcal / kg) on the horizontal axis. The cycles indicated by the “1” solid line and the “2” broken line in FIG.
It shows operating conditions under cooling standard conditions and cooling overload conditions of IS B 8616). Under the cooling overload condition, since the outdoor air temperature is high, the condensing capacity of the outdoor heat exchanger 3 decreases, the condensing temperature rises, and the supercooling degree SC of the liquid refrigerant at the outlet of the outdoor heat exchanger 3 shown in FIG. Decrease. Further, the discharge pressure Pd, the suction pressure Ps, and the discharge refrigerant temperature Td of the compressor 1
Rises, and particularly the discharge pressure Pd and the discharge refrigerant temperature T
d rises significantly. During the cooling overload operation, the pressure at the inlet of the outdoor heat exchanger 3 that operates as a condenser increases with the remarkable rise of the discharge pressure Pd and the discharge refrigerant temperature Td. When the pressure applied to the pressure receiving port 19 of the pressure on-off valve 16 exceeds the set value, the sliding valve 24 slides to the position shown in FIG. 3, and the communication hole 25 moves between the on-off valve inlet 20 and the on-off valve outlet 21. Correspondingly, the bypass circuit 15 is opened. In the cooling operation with the bypass circuit 15 opened, the condensing restriction is always generated only by the depressurizing capillary 42, and the depressurizing action is reduced by the heating / cooling normal depressurizing capillary 44 bypassed by the bypass circuit 15. Is done. As a result, even when the compressor 1 without the capacity control function, for example, without the inverter control, is mounted, the required refrigerant control can be obtained, and the cooling cycle suitable for the cooling overload condition can be easily achieved with a small cost and stable. Can drive.

The high-temperature, high-pressure gas refrigerant discharged from the compressor 1 is condensed in the outdoor heat exchanger 3 to become a high-pressure liquid refrigerant, and further decompressed by the decompression capillary tube 41. The cycle of evaporating and returning to the compressor 1 with the gas refrigerant is repeated in the same manner as during normal cooling. Further, a change in the cycle operation state based on a change in the indoor and outdoor temperature conditions in the refrigerant circuit 8 will be described with reference to FIG. That is, when the temperature inside and outside the room increases during the cooling operation and changes from the standard condition to the overload condition, as described above, the discharge pressure Pd, the suction pressure Ps, the discharge refrigerant temperature Td, the condensing pressure,
The condensing temperature rises, and the cycle indicating the operating state changes from the “1” solid line shown in FIG. 4 to the “2” broken line cycle. At this time, if the condensing pressure exceeds the set value, the bypass circuit 15 is opened, the pressure reducing action is eased, and the circulating refrigerant flow rate in the cycle increases. This allows
The cycle indicating the operation state is changed from “2” shown in FIG.
1) The cycle shown by the solid line is approached.

Embodiment 2 FIG. In the embodiment of FIGS. 1 to 4, the outdoor heat exchanger 3 that operates as a condenser to open and close the bypass circuit 15 of the pressure reducing capillary 41.
Is shown as a mechanical pressure on-off valve 16 which can be controlled in a self-contained manner by the pressure at the inlet of the valve. However, a combination of a pressure switch for electrically turning on / off the pressure on / off valve 16 at a set pressure and a solenoid valve for opening / closing the valve by ON / OFF of the pressure on / off valve 16 is also provided. The throttle mechanism 17 can be formed by a combination of a bimetal thermo-therm and an electromagnetic valve for turning ON / OFF the switch.
The required refrigerant control can be obtained even with the refrigerant circuit 8 having such a throttle mechanism 17. Therefore, although detailed description is omitted, it is obvious that the same operation as the embodiment of FIGS. 1 to 4 can be obtained.

[0014]

As described above, the present invention relates to a refrigerant circuit in which a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducing capillary, an indoor heat exchanger, and a liquid storage device are sequentially connected by refrigerant piping.
Forming a depressurizing capillary, and both a constant-pressure depressurizing capillary arranged near the outdoor heat exchanger and arranged in series with each other, and a heating-time depressurizing capillary provided near the indoor heat exchanger, and both of the above A heating / cooling normal-time depressurizing capillary provided between the heating and cooling normal-time depressurizing capillary, one end of which is provided for the refrigerant circuit four-way valve and the outdoor heat exchanger.
The other end is depressurized during normal heating / cooling of the refrigerant circuit.
The use capillary and the bypass circuit connected between the heating time of pressure reduction capillary, the diaphragm mechanism disposed in the bypass circuit of this,
It is provided with a pressure switch valve operated by a slide valve which slides in accordance disposed bypass circuit to the chamber outside the heat exchanger inlet pressure. Thereby, when the pressure at the entrance of the outdoor heat exchanger exceeds the set value during the cooling operation, the bypass circuit provided for the heating / cooling normal-time depressurizing capillary opens,
The decompression effect is reduced. Therefore, the pressure on-off valve is simply configured and operates reliably, the control method of the circulating refrigerant flow rate is simple, the air conditioner can be manufactured at low cost, and even under cooling overload conditions, and The flow rate of the circulating refrigerant is effectively increased, and a cooling cycle adapted to the cooling overload condition can be performed, thereby obtaining a stable operation state.

[Brief description of the drawings]

FIG. 1 is a conceptual overall configuration diagram showing a first embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view of the pressure on-off valve of FIG. 1;

FIG. 3 is a view for explaining the operation of the pressure on-off valve of FIG. 2;

FIG. 4 is a Mollier diagram showing a cycle operation state according to a change in temperature conditions for the apparatus of FIG. 1;

FIG. 5 is a diagram corresponding to FIG. 1 showing a conventional air conditioner.

[Explanation of symbols]

1 compressor, 2 four-way valve, 3 outdoor heat exchanger, 5 indoor heat exchanger, 6 liquid storage, 7 refrigerant piping, 8 refrigerant circuit,
15 bypass circuit, 16 pressure on-off valve, 17 throttle mechanism, 24 sliding valve, 41 pressure reducing capillary, 42 constant pressure reducing capillary, 43 heating pressure reducing capillary, 44 heating
Capillary tube for decompression during normal cooling.

Claims (1)

(57) [Claims] 1. A refrigerant circuit in which a compressor, a four-way valve, an outdoor heat exchanger, a decompression capillary, an indoor heat exchanger, and a pressure accumulator are sequentially connected by refrigerant piping, and the decompression capillary formed in series with each other. Both the normally depressurized capillary arranged near the outdoor heat exchanger and the heating depressurized capillary provided near the indoor heat exchanger, and the normal heating / cooling depressurization provided between the two. And one end provided for the heating / cooling normal pressure reducing capillary,
Connected between the four-way valve of the medium circuit and the outdoor heat exchanger.
The other end is for depressurization of the refrigerant circuit during normal heating and cooling.
A bypass circuit connected between the capillary and the heating time of pressure reduction capillary, the diaphragm mechanism disposed in the bypass circuit of this, according to the pressure of the upper Symbol outdoor heat exchanger inlet is disposed above Kiba bypass circuit An air conditioner provided with a pressure switching valve operated by a sliding valve that slides.