JPH0367964A - Air conditioner - Google Patents

Abstract

PURPOSE:To perform the capacity control operation with avoiding a reduction in the heating and cooling capacity and over-heating of a motor by a method wherein a first on-off valve which opens and closes a bypass circuit and a second on-off valve which opens and closes a refrigerant feed circuit are provided, and the first and second on-off valves are on-off controlled corresponding to the refrigerant delivery temperature of a multiple-cylinder compressor. CONSTITUTION:A portion of refrigerant discharged from a multiple-cylinder compressor 1 is returned to the inlet side of the compressor 1 through a bypass circuit 28 and an on-off valve 29 opens and closes the bypass circuit 28. In a heat exchanger 31, heat exchange takes place between a liquid refrigerant pipe 30, which is connected to room heat exchangers 12 and 15, and a refrigerant suction pipe 19 for a cylinders of the multiple-cylinder compressor 1. A liquid refrigerant feed pipe 32 connects the refrigerant suction pipe 19 on the upstream side of the heat exchanger 31 and the liquid refrigerant pipe 30 and is opened and closed by an on-off valve 33. A temperature detector 34 detects the refrigerant delivery temperature of the multiple-cylinder compressor 1. An on-off valve controller 37 opens the on-off valves 29 and 33 when the temperature detected by the temperature detector 34 is higher than a preset over- heat preventing temperature, and closes the on-off valves when it is lower.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air conditioner that performs capacity control by controlling the opening and closing of refrigerant suction passages to cylinders with multiple cylinder pressures IBM.

[Conventional technology]

FIG. 4 is a refrigerant circuit diagram showing a conventional air conditioner.

In the figure, (1) is the first cylinder (1a) with the same capacity.
and a second cylinder (1h), and 12 motors (2)
This is a multi-cylinder compressor consisting of a high-pressure shell-type two-cylinder rotary compressor that is driven by a gas refrigerant and compresses gas refrigerant. Cooled by refrigerant gas. (3) is a four-way switching valve that switches the refrigerant circuit;
4) is an outdoor heat exchange device equipped with an outdoor heat exchanger (4a) and a blower (51 and a check valve [71 is connected in parallel with the expander j former 6); (12) is the first indoor heat exchanger; Inner heat exchanger (
12a), a first indoor heat exchanger (15) equipped with an expansion mechanism (8) to which a blower (13) and a check valve (9) are connected in parallel; 15a), an expansion mechanism 00) in which a blower (14) and a check valve (11) are connected in parallel;
6) is an accumulator, and the above (1) to (16) are connected by refrigerant piping to form a refrigeration cycle.

(+7) (18) is an electromagnetic on-off valve connected to the inlet side of the first and second indoor heat exchanger (12) (+5) during cooling operation, and this electromagnetic on-off valve (17) (18) The above-mentioned] and second indoor heat exchange devices (1
2> Controls the operation of <15). (19) is a refrigerant suction path consisting of a refrigerant pipe connecting the outlet side of the accumulator (16) and the input side of the multi-cylinder compressor (1), and this refrigerant suction path (one) is connected to the first cylinder. A refrigerant suction passage (19a) leading to the second
Refrigerant suction passage (2+) leading to cylinder (1b) (2
2) It is divided into two. <231 (24) is an electromagnetic on-off valve connected in series, and the electromagnetic on-off valve (23) is
is connected to the refrigerant suction passage (21) of the second cylinder (1b) of the multiple cylinder pressure machine (11) through the refrigerant pipe (25), and the electromagnetic on-off valve (24) is connected to the refrigerant pipe (26).
It is connected to the discharge side of the multiple cylinder pressure 111i11fi [1,1. A series connection point between the electromagnetic on-off valve (23) and the electromagnetic on-off valve (24) is connected to the electromagnetic on-off valve (20>) via a refrigerant pipe (27).

FIG. 5 FIG. 6 is a longitudinal sectional view of the on-off valve (20) described in 1. In the figure, (20b) is the first coupling hole formed on the side surface of the on-off valve body (20a) and connects the refrigerant suction passage (21), and (20c) is the first coupling hole formed on the side surface of the on-off valve body (20a), and (20c) is the first coupling hole formed on the side surface of the on-off valve body (20a). A second coupling hole (20d) formed at the lower end of the on-off valve body (20a) and connecting the refrigerant suction passage (22) is a third coupling hole connecting the refrigerant pipe (27);
These first coupling holes (20b) to third coupling holes <20d
) are communicated through a communication hole (20e). (2Of)
slides within the communication hole (20e) and connects to the first coupling hole (20e).
20h) and the second coupling hole (20c), and also closes communication between the first and second coupling holes (20b) (20c) and the third coupling hole (20d). . The on-off valve (20) is constructed as follows,
For example, when the compressor (1) is in operation, if the electromagnetic on-off valve (24) in Fig. 4 is closed and the electromagnetic on-off valve (23) is open, the refrigerant pipe (27) and the refrigerant suction passage ( 21) through the electromagnetic on-off valve (23), and by the operation of the second cylinder (1b), the pressure in the refrigerant pipe (27L refrigerant suction i\8 (2+) is reduced to within the refrigerant suction passage (22). , the slider (2Of) is pushed down by the flow of the refrigerant as shown in Fig. 6, and the first and second coupling holes (20b) (20c) are brought into conduction and the refrigerant flows through the first and second coupling holes (20c). 2 cylinders (Ia) (lb), and the multi-cylinder compressor (1) is in full operation at 1100% capacity.Also, when the multi-cylinder compressor (↑) is in operation, the electromagnetic on-off valve ( 24) is open and the electromagnetic on-off valve (23) is closed, the pressure in the refrigerant pipe (27) is the same as the discharge pressure and higher than the pressure in the refrigerant suction passage (22), and the slider (2Of) moves as shown in Fig. 5. , the flow of refrigerant to the second cylinder (I b ) is closed and the multi-cylinder compressor (1) is only supplied with refrigerant to the first cylinder (1a). , cylinder operation will be performed at 50% capacity.

Conventional air conditioners were configured as described above, so that, for example, during cooling operation or defrosting operation, the high temperature and high pressure refrigerant discharged from the multiple cylinder compressor (1) passes through the four-way switching valve (3). Then, it is sent to the outdoor heat exchanger (4), where it exchanges heat with the air sent from the air blower 18 F51 and is liquefied here. Next, this liquefied refrigerant, that is, liquid refrigerant, passes through the check valve (7), passes through the electromagnetic on-off valve (+7) (+8>, and expands to the expansion mechanism +8+00), and is then depressurized and transferred to the indoor heat exchanger (12). (+5) exchanges heat with the air blown from (13) (+4.) and is vaporized again. After the vaporized refrigerant passes through the four-way switching valve (31) and the accumulator (16), one side passes through the refrigerant suction passage (19) (19a) to the first cylinder (1a), and the other side goes through the refrigerant suction passage (19) (19a), and the other side during full operation. That is, the electromagnetic on-off valve (23> (+7) (1, 8) is open, and the electromagnetic on-off valve (24) is connected to the refrigerant suction path (19) at the leap.
(22), the on-off valve (20), and the refrigerant suction path (21), and is sucked into the second cylinder (1b).

During cylinder operation, that is, when one of the electromagnetic on-off valves (17) and (18) is open and the other is closed, when the electromagnetic on-off valve (27+) is open and the electromagnetic on-off valve (23) is closed, the on-off valve (20) Since the circuit from the refrigerant suction passage (22) to the refrigerant suction passage (21) is closed by the slider (2Of), the refrigerant is not supplied to the second cylinder (1b) and is supplied to the first cylinder (Ia ). In this way, a refrigeration cycle is formed.

Further, during heating operation, the refrigerant circuit is switched in the direction shown by the dotted line by the four-way switching valve (3), and the refrigerant flows in the direction shown by the dotted line arrow. That is, the high temperature and high pressure refrigerant discharged from the multiple cylinder compressor (1) passes through the four-way switching valve (3), is sent to the indoor heat exchangers (+2) and (+5), and is sent to the blower (13).
It exchanges heat with the air sent from (+4) and is liquefied here. Next, this liquefied refrigerant, that is, liquid refrigerant, passes through a check valve +9HI+) during full operation and an electromagnetic on-off valve (
+7) (+8) and is depressurized by the expansion mechanism (6).

The depressurized refrigerant is sent to the outdoor exchanger (4a) and sent to the blower (5).
It exchanges heat with the air sent in and is re-vaporized.

After the vaporized refrigerant passes through the four-way switching valve F31 and the accumulator (16), one side is refrigerant suction li! 8 (19
) (19a) to the first cylinder (1a), the other side is the refrigerant suction path
), the second cylinder (1b
). During cylinder operation, the circuit from the refrigerant suction passage (22) to the refrigerant suction passage (21) is closed by the slider <20fl of the on-off valve (20), so the refrigerant does not flow into the second cylinder (1b). It is not supplied and is supplied only to the first cylinder (1a).

In this way, a refrigeration cycle is formed.

[Problem to be solved by the invention]

In the conventional air conditioner as described above, during capacity control operation using the cylinder, the refrigerant suction passage of a predetermined cylinder (cylinder) of the multi-cylinder compressor is blocked and no refrigerant is supplied, so the flow rate of refrigerant flowing through the refrigeration cycle is reduced. is significantly reduced, and the cooling effect of the motor of a multi-cylinder compressor is significantly reduced.
There is a problem in that it causes the motor of the multiple cylinder compressor to overheat, thereby significantly shortening the life of the multiple cylinder compressor.

This invention was made to solve these problems, and provides an air conditioner that can perform capacity control operation without causing overheating of the motor of a multiple cylinder compressor and without reducing the air conditioning capacity. The purpose is to

[Means to solve the problem]

The air conditioner according to the present invention includes a bypass circuit that bypasses a part of the refrigerant discharged from the multiple cylinder compressor to the input side of the multiple cylinder compressor (7), (8) cylinder compressor, and a bypass circuit that opens and closes this bypass circuit. 1 on-off valve, and the first and second valves.
a heat exchange section for exchanging heat between a liquid pipe consisting of refrigerant piping connecting between the heat exchangers and a refrigerant suction path to the cylinders of the plural cylinder compressor; and a refrigerant suction on the side opposite to the compressor of the heat exchange section. a liquid refrigerant injection circuit that connects the passage section and the liquid pipe section; a second on-off valve that opens and closes the liquid refrigerant injection circuit; a temperature detector that detects the temperature of the refrigerant discharged from the plurality of cylinder compressors; The apparatus is provided with an on-off valve control device that controls opening and closing of the first and second on-off valves according to the temperature detected by the temperature detector.

[For production]

The discharge refrigerant temperature of the multiple cylinder compressor of the air conditioner configured as above is detected by a temperature detector, and this detected temperature is compared with a preset overrise prevention temperature in the on-off valve control device. In this case, the first and second on-off valves are opened. By opening the first on-off valve, the discharged refrigerant is bypassed to the input side of the multiple cylinder compressor, and the discharge refrigerant pressure of the multiple cylinder compressor is reduced. Accordingly, the temperature of the refrigerant discharged from the multiple cylinder compressor decreases, and a decrease in suction pressure is prevented. On the other hand, when the second on-off valve is opened, liquid refrigerant is injected from the liquid pipe section into the refrigerant suction path of the multiple cylinder compressor through the liquid refrigerant injection circuit, and this liquid refrigerant becomes a low-pressure, low-temperature liquid refrigerant. In conjunction with the reduction in discharge refrigerant temperature due to opening, the motor of the multi-cylinder compressor is cooled and its overheating is prevented. In addition, the degree of subcooling of the liquid refrigerant passing through the refrigerant suction path increases in the liquid pipe due to heat exchange between the liquid refrigerant suction path and the liquid pipe, which increases the flow rate of refrigerant flowing through the expansion mechanism and the first opening/closing. In cooperation with prevention of a drop in suction pressure due to opening of the valve, a drop in heating and cooling capacity is prevented.

〔Example〕

FIG. 1 is a refrigerant circuit diagram of an air conditioner showing an embodiment of the present invention. In FIG. 1, (1) to (27) indicate the same or equivalent parts as those of the conventional air conditioner described above, and therefore the explanation thereof will be omitted. (28) is a multiple cylinder compressor (1)
The bypass circuit is connected to the discharge side of the compressor and the input side of the accumulator (16), and bypasses a part of the refrigerant discharged from the plural cylinder compressor to the input side of the accumulator (16). (29) is the first on-off valve that opens and closes the bypass circuit (28), and (30) is the outdoor heat exchange device (4).
) and the first and second indoor heat exchange devices (12) <15)
The liquid pipe (31) consisting of refrigerant pipes connecting the liquid pipes (31) is a heat exchange part that exchanges heat between the liquid refrigerant flowing in the liquid pipe (30) and the refrigerant flowing in the refrigerant suction passage (one). The exchange part (31) is formed by, for example, providing a part of the liquid pipe (30) in contact with or in close proximity to the refrigerant suction pipe (19). (32) is a liquid refrigerant injection circuit that connects the liquid pipe (30) and the refrigerant suction path section on the opposite compressor side of the heat exchange section (31) in the refrigerant suction R (19);
3) is a second electromagnetic on-off valve that opens and closes the liquid-liquid refrigerant injection circuit 32), and (34) is a temperature detector that detects the discharge refrigerant temperature, on the discharge side of the multiple cylinder pressure w4 machine (1). is installed in the refrigerant piping. (35) is an over-rise prevention judgment circuit, and its operation is as shown in FIG. If it is high, an overheat prevention activation signal is output, and after outputting the overheat prevention activation signal, when the temperature becomes lower than the detection temperature Td or the overheat prevention release temperature Tb, which is set lower than the overheat prevention temperature Ta in advance, Outputs overheat prevention release signal. (36) is the output signal of the over-rise prevention judgment circuit (35) or opens the above-mentioned first and second electromagnetic on-off valves in the case of the over-rise prevention signal, and in the case of the over-rise prevention release signal, the above-mentioned first and second A control circuit (37) for controlling the electromagnetic on-off valve to close is an on-off valve 1i1J control device consisting of the above-mentioned over-rise prevention judgment circuit (35) and the above-mentioned control circuit (36).

Figure 2 shows the overheat prevention judgment circuit (35) and the control circuit (35).
6) is a flowchart of the on-off valve control device (37). First, in step (38), it is determined whether the overrise prevention activation signal is being outputted. If not, the process proceeds to step (39), and if it is being outputted, the process proceeds to step (42). In step (39), it is determined whether the detected temperature Td is higher than the overrise prevention temperature Ta, and if it is, step (39) is determined.
40) to output an over-rise prevention activation signal, and step (41)
Then, open the first electromagnetic on-off valve (29) and the second electromagnetic on-off valve (11) (12) and return to step (38).

If the judgment result in step 39) is not large, the process returns to step (38). On the other hand, in step (42), it is determined whether the detected temperature Td is smaller than the overrise prevention release temperature Tb,
If it is smaller, an overrise prevention release signal is output in step (43), the first electromagnetic on-off valve (two) and the second electromagnetic on-off valve (33) are closed in step (44), and step (38) is performed.
Return to ). If the determination result in step (42) is not small, the process returns to step (38).

In the air conditioner configured as described above, when the discharge refrigerant temperature of the multiple cylinder compressor (1) is high, the temperature detector (34) detects the discharge refrigerant temperature as the detected temperature Td, and determines whether to prevent excessive rise. Mouth 1i'a (35), control circuit (3
6), the first electromagnetic on-off valve (29) and the second electromagnetic on-off valve (33) are installed based on the flowchart in FIG.
becomes open.

By opening the second electromagnetic on-off valve (33), condensation occurs in the outdoor heat exchanger (4a) during cooling operation, and in the indoor heat exchanger (12a) (15a) during heating operation. The high-pressure liquid refrigerant is injected from the liquid pipe (30) through the liquid refrigerant injection circuit (32) and the second electromagnetic on-off valve (33) into the refrigerant suction passage (one), becoming a low-pressure and low-temperature liquid refrigerant. The liquid refrigerant is supplied to the multiple cylinder pressure 1 fi (11) through the heat exchanger (31).In this way, when the discharge refrigerant temperature of the multiple cylinder compressor (1) becomes higher than the preset overrise prevention temperature Ta Liquid refrigerant is injected into the multiple cylinder pressure m machine (1), and overheating of the morph (2) of the multiple cylinder compressor (1) is prevented.

Furthermore, the liquid refrigerant supplied from the liquid pipe (30) to the liquid refrigerant suction path (19) is supplied as a low-pressure, low-temperature liquid refrigerant to the refrigerant suction path (19).
9) through the heat exchange section (31), the liquid pipe (
30) and passes through the heat exchange section (31), the high-pressure liquid refrigerant is cooled to increase the degree of supercooling. As a result, the expansion mechanism (F8) is activated during refrigerant operation, and the expansion mechanism (6) is activated during heating operation.
The flow rate of refrigerant flowing through the expansion mechanism +8] (10) or expander m (61) is prevented from decreasing by causing the refrigerant to flow through the liquid refrigerant injection circuit (32). , it is possible to prevent the cooling capacity or heating capacity from decreasing.Also, the second electromagnetic on-off valve (
By opening 33), the refrigerant supplied to the indoor heat exchanger (12a) (15a) during cooling operation and to the outdoor heat exchanger (4a) during heating operation decreases, reducing the suction pressure and reducing the indoor side heat exchanger. It is possible to prevent the heat exchangers (12a) (15a) and the outdoor heat exchanger (4a) from freezing.

Also, by opening the first electromagnetic on-off valves (two), the refrigerant discharged from the multiple cylinder compressor (1) is bypassed to the suction side of the multiple cylinder compressor (1), and the refrigerant is bypassed to the suction side of the multiple cylinder compressor (1).
1) The discharge pressure decreases and the suction pressure increases, so the refrigerant circulation amount of the multi-cylinder compressor (1) increases, preventing a decrease in cooling and heating capacity, and the increase in suction pressure increases the evaporation pressure. 1. Due to the decrease in the discharge pressure, the discharge refrigerant temperature of the multiple cylinder compressor decreases and the motor of the multiple cylinder compressor is prevented from overheating. .

As described above, air conditioning operation can be performed without reducing the heating and cooling capacity or overheating the motor.

In the above embodiment, an air conditioner using a high-pressure shell type 2-cylinder rotary compressor was described in which the compressor motor is cooled with compressed refrigerant, but the compressor motor is cooled with uncompressed refrigerant. It may be a low-pressure shell type two-cylinder rotary compressor that cools the air, or it may be a compressor with two or more cylinders.

〔Effect of the invention〕

The present invention includes a bypass circuit that bypasses a portion of the refrigerant discharged from a multiple cylinder compressor to the input side of the multiple cylinder compressor, a first on-off valve that opens and closes this bypass circuit, one of which is a condenser and the other is an evaporator. a heat exchange section for exchanging heat between a liquid pipe consisting of a refrigerant pipe connecting between a first and second heat exchanger serving as a heat exchanger and a refrigerant suction circuit of the plural cylinder compressor; and a heat exchange section between the liquid pipe and the heat exchange section. A liquid refrigerant injection circuit that connects the refrigerant suction passage section on the opposite side of the compression i, and a second on-off valve that opens and closes this liquid refrigerant injection circuit, are provided, and the temperature of the discharge refrigerant of the two-liquid multiple cylinder compressor is controlled. Accordingly, the first and second on-off valves are controlled to open and close, and by this control, the discharged refrigerant is bypassed from the two-liquid bypass circuit to the input side of the multiple cylinder compressor;
In cooperation with liquid refrigerant injection from the refrigerant injection circuit to the refrigerant suction path, the motor of the multiple cylinder compressor (15) is cooled, and the refrigerant discharged from the bypass circuit to the input side of the multiple cylinder compressor is cooled. This prevents the cooling and heating capacity from decreasing due to the heat exchange between the bypass and the liquid pipe and the refrigerant suction path, which effectively cools the motor and prevents the cooling and heating capacity from decreasing. This can be done without overheating of the motor and the reliability of the air conditioner is improved.

[Brief explanation of drawings]

Fig. 1 is a refrigerant circuit diagram of an air conditioner showing an embodiment of the present invention, Fig. 2 is a flowchart 1 to 1 showing the operation of the on-off valve control device shown in Fig. 1, and Fig. 3 is a diagram similar to that shown in Fig. 1. 4 is a refrigerant circuit diagram of a conventional air conditioner, and FIGS. 5 and 6 are longitudinal sections showing the detailed structure of the on-off valve shown in FIG. 4. It is a diagram. In the figure, (28) is the bypass circuit, (2) is the first
(31) is a heat exchange part, (32) is a liquid refrigerant injection circuit, (33) is a second electromagnetic on-off valve, (34) is a temperature detector, and (37) is an on-off valve control device. be. Note that the same reference numerals in the figures do not indicate the same or equivalent parts.

Claims (1)

[Claims] A refrigeration cycle including a plurality of cylinder compressors having a plurality of cylinders, a four-way switching valve, a first heat exchanger, a thermal expansion mechanism, and a second heat exchanger sequentially connected by refrigerant piping, Capacity control is performed by controlling the opening and closing of a refrigerant suction passage to a predetermined cylinder of the multiple cylinder compressor, wherein a part of the refrigerant discharged from the multiple cylinder compressor is transferred to the input side of the multiple cylinder compressor. a bypass circuit that bypasses the bypass circuit, an on-off valve that opens and closes the bypass circuit, a liquid pipe consisting of the refrigerant pipe that connects the first and second heat exchangers, and a refrigerant suction path of the multiple cylinder compressor. a heat exchange section for exchanging heat; a liquid refrigerant injection circuit that connects the refrigerant suction path section on the side opposite to the compressor of the heat exchange section and the liquid pipe section; and a second opening/closing circuit that opens and closes the liquid refrigerant injection circuit. A temperature detector that detects the temperature of the refrigerant discharged from the multiple cylinder compressor, and an on-off valve control device that controls opening and closing of the first and second on-off valves according to the temperature detected by the temperature detector. An air conditioner characterized by: