CN1118860A - air conditioner - Google Patents

Abstract

The purpose of the present invention is to provide an air conditioner capable of selecting the optimum control for cooling the room and heating the room, and performing high-efficiency operation. Among them: the compressor is a compressor that selectively switches the flow direction of the refrigerant flowing out of compressor 1 by four-way valve 2, and can be used for room cooling and room heating. The control of room cooling is placed on the suction side of compressor 1. Based on the temperature detection of the first temperature sensor 10 and the third temperature sensor 12 placed in the indoor heat exchanger 5, the opening degree of the flow regulating valve 4 is controlled so that the degree of superheat is a certain value, and the control of room heating is controlled by placing Based on the temperature detection of the second temperature sensor 11 on the output side of the compressor 1, the opening degree of the flow regulating valve 4 is controlled to reach a given output temperature.

Description

air conditioner

The present invention relates to an air conditioner capable of heating or cooling a room using a refrigeration cycle with an electric expansion valve.

An air conditioner is a device that has a refrigeration cycle composed of a compressor, an outdoor heat exchanger, a pressure reducing valve, and an indoor heat exchanger connected in sequence, and circulates the refrigerant while changing its state in the refrigeration cycle to condition the indoor air.

In the air conditioner capable of cooling or heating, it is equipped with a four-way valve that changes the direction of refrigerant flow. During cooling, the refrigerant output from the compressor is switched to the side of the outdoor heat exchanger, and the refrigerant flows from the outdoor heat exchanger along the pressure reducer. The indoor heat exchanger sequentially flows back to the compressor, cooling the room. That is, when cooling, the above-mentioned outdoor heat exchanger is used as a condenser, and the indoor heat exchanger is used as an evaporator.

On the other hand, when heating, the refrigerant output from the compressor is switched to the side of the indoor heat exchanger, and the refrigerant flows from the indoor heat exchanger along the outdoor heat exchanger of the reducer to return to the compressor to heat the room. That is, when heating, the above-mentioned indoor heat exchanger is used as a condenser, and the outdoor heat exchanger is used as an evaporator.

Moreover, during operation, the speed of the compressor should be controlled according to the air-conditioning load (equivalent to the difference between the indoor temperature and the set temperature), so as to exert the best cooling or heating capacity corresponding to the air-conditioning load.

As a pressure reducer, for example, a flow control valve with adjustable opening can be used. Also, detect the degree of superheat of the refrigerant in the evaporator (the temperature difference between the temperature of the refrigerant at the inlet of the evaporator and the temperature of the refrigerant at the outlet), regardless of whether the speed changes or not, as long as the degree of superheat is a certain value, the flow regulating valve will be controlled. of the opening.

In short, when the degree of superheat is greater than a certain value, the opening of the flow regulating valve is increased to increase the amount of refrigerant flowing to the evaporator. When the degree of superheat is smaller than a certain value, the opening degree of the flow regulating valve is reduced to reduce the amount of refrigerant flowing to the evaporator.

By controlling the degree of superheat, keeping the degree of superheat at a certain value can obtain a good refrigeration capacity (efficiency coefficient), and at the same time, by ensuring a certain degree of superheat, the phenomenon of liquid refrigerant returning to the compressor is prevented.

Conventionally, whether it is room cooling or room heating, the control of the above-mentioned refrigeration cycle has been performed mainly by superheat control.

Here, there are the following problems to be solved with respect to the control mainly based on the degree of superheat control described above.

The degree of superheat is controlled by detecting the degree of superheat, that is, detecting the difference between the refrigerant inlet temperature and the outlet temperature of the condenser (the superheat of the saturation temperature of the refrigerant), so the indoor heat exchanger is used as the cooling of the condenser. During operation, it should be a very good control method to directly control the heat exchanger used for indoor air conditioning (hereinafter referred to as the heat exchanger on the utilization side).

On the one hand, the condenser becomes an outdoor heat exchanger during heating, not a heat exchanger on the utilization side. However, since the degree of superheat control is to control the temperature of the refrigerant sucked into the compressor, it is also to indirectly control the suction temperature of the condenser (the utilization side heat exchanger) which is the temperature of the output refrigerant. Therefore, the control of the use-side heat exchanger is performed indirectly.

However, since the evaporator is located outdoors where the air temperature is low during heating, the degree of superheat cannot be greater than that during room cooling, and the temperature of the refrigerant in the heat exchanger on the utilization side cannot be properly controlled during the control of the degree of superheat. For this reason, the efficiency at the time of heating is low.

In view of the above problems, it is an object of the present invention to provide an air conditioner that can select appropriate controls for heating and cooling and operate efficiently.

The first device is an air conditioner, which is composed of a compressor, an indoor heat exchanger, a flow adjustment valve for decompression, and an outdoor heat exchanger connected in sequence, and there is also a flow path switch for switching the flow direction of the operating fluid between indoor cooling and indoor heating. The valve refrigeration cycle is characterized in that there is a detection device for detecting the degree of superheat of the working fluid in the indoor heat exchanger when the room is cooled, and there is a detection device for detecting the outlet temperature of the working fluid discharged from the compressor when heating. The detection device is useful when the superheat detected by the above-mentioned superheat detection device reaches the set value when the room is cooling, and controls the opening of the above-mentioned flow regulating valve. At the same time, when the room is heated, the above-mentioned outlet temperature detection device detects A device that controls the opening of the above-mentioned flow regulating valve when the outlet temperature reaches the set value.

The second device is in the above-mentioned air conditioner of claim 1, and also has the following features: there is a device for controlling the speed of the compressor corresponding to the load of the air conditioner; when the room is heated, it detects the outlet temperature of the operating fluid discharged from the above-mentioned compressor The detection device; the control device, which stops the control when the superheat reaches a certain value when the outlet temperature detected by the detection device exceeds the set temperature, and reduces the speed of the compressor when the above-mentioned outlet temperature is lower than the set value, and the above-mentioned outlet When the temperature is lower than the set value, the opening degree of the above-mentioned flow regulating valve is controlled.

The third device is that the air conditioner has the following characteristics: the compressor has an airtight casing, the compression part installed in the casing to fill the compressed high-pressure working fluid inside the airtight casing, and the switch outlet side is arranged in the airtight casing The flow path switching valve on the inlet side; it is composed of a compressor, an indoor heat exchanger, a flow regulating valve for decompression, and an outdoor heat exchanger connected in sequence. By switching the above flow path switching valve, the outlet side of the above compressor and the The inlet side selects the refrigeration cycle of indoor heating and indoor cooling; there is a first temperature detection device installed on the piping connecting the compressor and the indoor heat exchanger; there is a device installed in the indoor heat exchanger to detect the refrigeration in the indoor heat exchanger A second temperature detection device for the temperature of the refrigerant; control the opening of the flow adjustment valve based on the refrigerant temperature detected by the first and second temperature detection devices.

The fourth device is that the air conditioner according to claim 3 also has the following features: there is a control device for controlling the opening of the above-mentioned flow regulating valve. Use the refrigerant evaporation temperature detected by the second temperature detection device to calculate the degree of superheat, and control the opening of the flow regulating valve with the degree of superheat as a certain value; The temperature of the refrigerant is used to control the opening of the flow rate adjustment valve with the temperature of the discharged refrigerant as a constant value.

For the air conditioner of claim 1, superheat control is performed when the room is cooled, output temperature is controlled when the room is heated, and the indoor heat exchanger that acts as an evaporator during cooling and a condenser during heating can be directly controlled.

For the air conditioner according to claim 2, when the temperature of the compressor rises abnormally during the cooling operation, the output temperature is controlled at the same time, so that damage to the compressor can be prevented.

The air conditioner of claim 3 is a compressor with a built-in switching valve, and a temperature detection device can detect the temperature of the operating fluid discharged from the indoor heat exchanger during cooling and the operation of flowing to the indoor heat exchanger during heating. The temperature of the fluid is used as the basis for controlling the air conditioner.

For the air conditioner according to claim 4, the temperature detected by the first and second temperature detection devices can be used as a basis to control the superheat degree during cooling and control the output temperature during heating.

Fig. 1(a) is a diagram showing the system and control circuit configuration for room cooling according to the first embodiment of the present invention, and Fig. 1(b) is a diagram showing the configuration of a four-way valve for room heating.

Fig. 2 shows a longitudinal sectional view of a compressor of a second embodiment.

Fig. 3 is same, (a) is the plan view of switching valve, (b) is the longitudinal sectional view along I-I line in (a), (c) is the transverse sectional view along II-II line among (a).

Fig. 4(a) is a system and control circuit configuration diagram when the room is cooled, and (b) is a configuration diagram when the room is heated.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

First, a first embodiment of the present invention will be described. This first embodiment is applicable to an air conditioner using a conventional compressor used heretofore.

1 in Fig. 1 (a) represents the compressor (CP). The compressor 1 sucks refrigerant in the direction indicated by the arrow (亻) in the figure, and outputs it in the direction indicated by the arrow (port) after compression. The four-way valve shown in Figure 2 is connected to the suction side and the output side of the compressor 1, and Figure 1(a) shows a state in which the four-way valve is in the middle.

In this intermediate state, the output side of the compressor 1 is connected to the outdoor heat exchanger 3 with piping. The outdoor heat exchanger 3 is sequentially connected to the pressure reducing flow control valve 4 and the indoor heat exchanger 5 through piping, and the indoor heat exchanger 5 is connected to the suction side of the compressor 1 through the four-way valve 2 through piping.

Furthermore, the above-mentioned compressor 1 is a so-called variable-capacity inverter compressor, which can be controlled according to the room cooling or heating load corresponding to the conversion circuit shown in FIG. 7 . In addition, the above-mentioned flow regulating valve 4 is a pulse motor valve (PMV) whose opening degree is continuously changed corresponding to the number of input pulses.

Moreover, the above-mentioned outdoor heat exchanger 3 is placed in an outdoor part not shown in the figure, and an outdoor fan represented by 8 in the figure is arranged in the outdoor part. The outdoor fan 8 introduces outdoor air to the outdoor heat exchanger 3, and the outdoor heat exchanger 3 efficiently exchanges heat with the outdoor air.

Also, the indoor heat exchanger 5 is placed in an indoor part not shown in the figure, and an indoor fan (cross-flow fan) represented by 9 in the figure is installed in the indoor part. The indoor fan 9 has a function of introducing indoor air into the indoor heat exchanger 5 and blowing the heat-exchanged air into the room.

Fig. 1 shows piping (cooling cycle) when cooling is performed. That is, the above-mentioned four-way valve 2 is set in an intermediate state in advance, and the refrigerant output from the above-mentioned compressor is indicated by a solid arrow, and sequentially passes through the four-way valve 2, the outdoor heat exchanger 3, the flow regulating valve 4, and the indoor heat exchanger. 5 and four-way valve 2 return to compressor 1.

Furthermore, when heating, the four-way valve 2 is switched as shown in Figure 1(b), and the refrigerant output from the compressor 1 passes through the four-way valve sequentially as indicated by the dotted arrows in this figure and Figure 1(a). 2. The indoor heat exchanger 5, the flow regulating valve 4, the indoor heat exchanger 3 and the four-way valve 2 return to the compressor 1. That is, a heating cycle is constituted.

Next, the control system of this air conditioner will be described.

As shown in FIG. 1( a ), a first temperature sensor 10 is attached to the suction piping of the compressor 1 , and a second temperature sensor 11 is attached to the output side piping. The first temperature sensor 10 detects the refrigerant intake temperature of the compressor 1 (refrigerant outlet temperature of the evaporator), and the second temperature sensor 11 detects the refrigerant output temperature of the compressor 1 (refrigerant inlet temperature of the condenser).

In addition, a third temperature sensor 12 is installed approximately in the middle of the indoor heat exchanger 5 . The third temperature sensor 12 is used when the indoor heat exchanger 5 is used as an evaporator to cool the room, and detects the evaporation temperature of the refrigerant.

On the one hand, as mentioned above, the inverter circuit 7 is connected to the compressor 1, and the inverter circuit 7 is connected to the commercial AC power supply 14. The conversion circuit 7 rectifies the voltage of the power supply 15, converts it into a voltage of a frequency corresponding to a command, and operates the motor provided in the compressor 1 with this voltage.

Furthermore, the commercial AC power source 14 is connected to the control section 18 via a step-down transformer 16 . The four-way valve 2 mentioned above, the flow regulating valve 4, the outdoor fan 8, the indoor fan 9, the first to the third temperature sensors 10 to 12, the conversion circuit 7, the remote control operator represented by 19 in the figure (hereinafter referred to as A remote controller) and an indoor temperature sensor represented by 20 are connected to the control section 18, respectively.

That is, the control part 18 is for controlling the whole air conditioner, and is normally hidden in the electric parts box provided in the said indoor part (not shown). Next, the function of the control section 18 will be described with reference to the operation of the air conditioner.

First, the operation during room cooling will be described.

The above-mentioned control part 18 puts the four-way valve 2 in an intermediate state to make the compressor run, and the refrigerant output from the compressor 1 passes through the four-way valve 2, the outdoor heat exchanger 3, the flow regulating valve 4, and the indoor heat exchanger 3. , Four-way valve 2 returns to the compressor, and the room implements cooling operation.

During the cooling operation, the indoor heat exchanger 5 of the heat exchanger for indoor air conditioning (hereinafter referred to as the utilization-side heat exchanger) functions as an evaporator.

Also, the control section 18 controls the compressor 1 according to the difference between the indoor temperature Ta detected by the indoor temperature sensor 20 installed in the indoor heat exchanger 5 and the temperature Ts set by the remote controller 19 (=Ta−Ts). The rotational speed F (the output frequency of the conversion circuit 7). In this way, the compressor 1 is operated according to the cooling load.

Also, let the difference (=Ts−Te) between the detected temperature (suction refrigerant temperature) Ts of the first temperature sensor 10 and the detected temperature (evaporation temperature) Te of the third temperature sensor 12 be The degree of superheat SH of the refrigerant within is detected within a predetermined control time (about 20 seconds to 50 seconds).

The control unit 18 controls the opening Q of the flow regulating valve 4 within the control time (about 20 seconds to 50 seconds) when the detected degree of superheat SH is a constant value. In this way, the power coefficient of the refrigeration cycle can be kept good by directly controlling the utilization side heat exchanger (indoor heat exchanger 5).

On the one hand, if the output refrigerant temperature Td detected by the second temperature sensor 11 is above the set value T2, and the detected temperature is lower than the set value T1, the speed of the compressor 1 is reduced, and the opening of the flow regulating valve is controlled. Make the output refrigerant temperature Td equal to the set value T1 (output temperature control). So far, abnormal heating of the compressor 1 can be effectively prevented, thereby effectively preventing damage of the compressor 1 due to sintering or the like.

According to the above control, the control unit 18 performs control mainly on superheat control during room cooling, and switches to output temperature control to keep the output temperature constant only when the refrigerant output temperature Td of the compressor 1 rises abnormally.

Next, the heating operation will be described.

The above-mentioned control part 18, after switching the four-way valve 2 as shown in the figure, operates the compressor 1, and the refrigerant output from the compressor 1 passes through the four-way valve 2, the indoor heat exchanger 5, the flow regulating valve 4, and the indoor heat exchange The device 3 and the four-way valve 2 are returned to the compressor 1. A heating operation is performed (shown by a dotted arrow in FIG. 1( a )).

In room heating operation, the indoor heat exchanger 5 of the side heat exchanger is used as a "condenser".

Also, the control section 18 detects the difference (=Ta−Ts) between the temperature Ts set by the remote controller 19 and the indoor temperature Ta detected by the indoor temperature sensor 20 as the air-conditioning load, and controls the compressor 1 corresponding to the air-conditioning load. The rotational speed F (the output frequency of the conversion circuit 7). In this way, the compressor 1 is operated according to the heating load.

In addition, the detection temperature (output refrigerant temperature) Tt of the second temperature sensor 11 is set as the output temperature, and detection is performed for a predetermined control time (about 20 seconds to 50 seconds).

The control unit 18 controls the opening Q of the flow rate regulating valve 4 for the control time (about 20 seconds to 50 seconds) so that the detected temperature Tt becomes a constant value (output temperature control). In this way, the temperature of the refrigerant flowing into the use-side heat exchanger (indoor heat exchanger 5) can be directly controlled, and the power coefficient of the refrigeration cycle can be kept high. At the same time, abnormal heating of the compressor 1 can be prevented, and damage such as sintering can be effectively prevented.

According to the above control, the above-mentioned control section 18 performs output temperature control and does not perform superheat degree control during room heating.

With such a configuration, the following effects are obtained.

First, the air conditioner performs control mainly based on superheat control when cooling the room, and performs control mainly based on output temperature control when heating the room.

According to this configuration, the indoor heat exchanger 5 as a heat exchanger can be directly controlled not only during cooling but also during heating, so that there is an effect that optimal control of indoor air conditioning can be performed.

That is, as described above, it is possible to control the refrigeration cycle by superheat control even during heating. The superheat degree control when heating the room is to control the superheat degree of the refrigerant, that is, the temperature of the refrigerant in the outdoor heat exchanger 3 that becomes an evaporator during heating, to control the temperature in the indoor heat exchanger 5 of the heat exchanger on the use side. temperature of the refrigerant.

Therefore, with this control method, the use-side heat exchanger can be directly controlled when the room is cooled, but often only indirectly can be controlled when the room is heated. For this reason, when heating a room with this control method, there is a possibility that the use-side heat exchanger (indoor heat exchanger 5 ) cannot be accurately controlled, and there is a concern that the efficiency (power coefficient) cannot be exhibited.

However, for the present invention, the temperature of the refrigerant in the indoor heat exchanger 5, which is the heat exchanger on the utilization side, can be directly controlled by the output temperature control during heating. Optimum control of heat exchangers to perform air conditioning with high efficiency (coefficient of power) according to operating conditions.

Second, there is an effect that it is easy to control during heating.

That is, when heating is performed, since the outdoor temperature is low, the degree of superheat cannot be larger than when cooling is performed (refrigerant cannot be superheated). Therefore, when the superheat degree is controlled during heating, there is a disadvantage that the control range is small and the control is difficult.

Also, during heating, the output temperature of the compressed refrigerant can directly affect the calorific value of the indoor heat exchanger, which is the heat exchanger on the utilization side, according to the degree of superheat of the refrigerant in the evaporator.

Regarding this point, in the case of the present invention, since the output temperature control can be performed regardless of the degree of superheat during room heating, the control of the air conditioner becomes easy, and there is an effect of optimal control corresponding to room heating. . Therefore, there is an effect of performing air conditioning with high efficiency (power coefficient) according to operating conditions.

Next, a second embodiment of the present invention will be described.

The air conditioner shown in the second embodiment uses the four-way valve built-in fluid compressor shown in 25 in FIG. 2 as the compressor. In addition, components other than the compressor 25 (switching valve) shown in the second embodiment are substantially the same as those in the above-mentioned first embodiment. Therefore, the detailed description of the same components with the same symbols will be omitted.

The four-way valve built-in fluid compressor 25, as shown in Figure 2, has a closed casing 26, is arranged in the casing 26 and compresses the low-pressure refrigerant sucked from the outside of the casing 26, and simultaneously compresses the compressed high-pressure refrigerant. Compression part 27 from which the refrigerant is output from the casing 26, the output pipe of high-pressure refrigerant to the outside of the casing 26 and the suction pipe of low-pressure refrigerant to the above-mentioned compression part 27 are placed in the above-mentioned casing 26 to rotate the valve body 28 and switch to the outside of the casing 26. The circular four-way switching valve 29.

Four-way valve 29, as shown in Figure 3, is provided with the valve seat 33 of three intermediary screw rods 30～32 at intervals of 90° in the circumferential direction, and three screw rods 30～32 are respectively connected with outdoor by piping 35～37 as shown in Figure 2 The heat exchanger 3, the compression part 27 in the casing 26 and the indoor heat exchanger 5 are connected.

Hereinafter, each of the pipes 35 to 37 will be referred to as an indoor heat exchanger side pipe 35 , an outdoor heat exchanger pipe 36 , and a compression section pipe 37 , respectively.

As shown in Fig. 3 (b) (c), on the above-mentioned valve body 28 installed under the above-mentioned valve seat 33, set and drive the valve body 28 and selectively communicate with the above-mentioned three screw rods 30-32 (each piping 35-37 ) in the two communication grooves 38 and the communication hole 39 that makes the residual screw communicate with the casing 26.

The communication groove 38 and the communication hole 39 are shown in figure (c), and they are similar in plan view, but the difference as shown in figure (b) is that the former is not connected on the valve body 28, and the latter is connected.

Furthermore, the portion 40 indicated by a grid is fixed to the above-mentioned valve body 28 and is combined with the communication hole 39 on the valve body 28 . A stopper for setting the rotation angle of the valve body 28 .

Further, on the outer peripheral surface of the valve body 28, a cylindrical permanent magnet 42 divided into an S pole 42a and an N pole 42b is fixed in the circumferential direction. And on the outside of the permanent magnet 42, as shown by 43 in the figure, a pair of struts 44 are extended relatively by the electromagnet with a certain gap.

Therefore, the electromagnet 43 is activated to magnetize the above-mentioned pair of support pieces 44 and then change their magnetic properties, and the valve body 28 is driven to rotate by the attractive or repulsive force of the support piece 44 and the permanent magnet 42 .

Due to this structure, when the room is cooled, the valve body 28 is driven to rotate, the outdoor heat exchanger pipe 35 connected to the outdoor heat exchanger 3 communicates with the inside of the cabinet 26 through the communication hole 39, and the outdoor heat pipe connected to the indoor heat exchanger 5 The exchanger pipe 37 communicates with the compressor-side pipe 35 through the communication groove 38 .

A pattern showing this state is Fig. 4(a).

25 among the figure is four-way valve built-in fluid compressor. A state in which the switching valve 29 is built in the compressor 25 is shown.

The high-pressure refrigerant filled in the casing 26 of the compressor 25 flows into the outdoor heat exchanger side pipe 35 through the communication hole 39 of the valve body 28 of the switching valve 29, and flows into the outdoor heat exchanger 3 as indicated by the arrow. The refrigerant passes through the outdoor heat exchanger 3 , the flow regulating valve 4 (pressure reducer), and the indoor heat exchanger 5 sequentially while undergoing a state change, and flows into the switching valve 29 of the fluid compressor 25 from the indoor heat exchanger side piping 37 . The switching valve introduces the refrigerant into the compression section side piping 36 through the communication groove 38 , and then introduces the refrigerant into the compression section 27 inside the casing 26 .

Accordingly, a room cooling cycle is formed, the outdoor heat exchanger 3 functions as a condenser, and the indoor heat exchanger 5 functions as an evaporator.

When the room is heated, the valve body 28 is driven to rotate, and the indoor heat exchanger side pipe 37 connected to the indoor heat exchanger 5 communicates with the inside of the casing 26 through the communication hole 39, and connects to the outdoor heat exchanger side of the outdoor heat exchanger 3. The pipe 35 communicates with the compression portion side pipe 36 through the communication hole 38 .

The pattern showing this state is Fig. 4(b).

The high-pressure refrigerant filled in the casing 26 of the compressor 25 flows into the indoor heat exchanger side pipe 37 through the communication hole 39 of the valve body 28 of the switching valve 29, and flows into the indoor heat exchanger 5 as indicated by the arrow. The refrigerant passes through the indoor heat exchanger 5 , the flow regulating valve 4 (pressure reducer), and the outdoor heat exchanger 3 sequentially while undergoing a state change, and flows into the switching valve 29 of the fluid compressor 25 from the outdoor heat exchanger side piping 35 . The switching valve 29 guides the incoming refrigerant through the communication groove 38 to the compression section side piping 36 , and then to the compression section 27 inside the casing 26 .

Accordingly, a room heating cycle is constituted, and the indoor heat exchanger 5 functions as a condenser and the indoor heat exchanger 3 functions as an evaporator, contrary to the case of cooling.

Next, the control system of the air conditioner will be described.

As shown in FIGS. 3 and 4 , a first temperature sensor 45 is attached to the indoor heat exchanger side piping 37 . Since the indoor heat exchanger side pipe 37 serves as the refrigerant suction pipe of the compressor when the room is cooled, and as the refrigerant output pipe when the room is heated, the first temperature sensor 45 detects the suction temperature of the refrigerant (indoor heat) when the room is cooled. Inlet temperature of the exchanger) can detect the output temperature of the refrigerant (inlet temperature of the indoor heat exchanger) when the room is heated.

Therefore, the first temperature sensor 45 is one sensor and can function as the first and second temperature sensors 10 and 11 in the first embodiment.

In addition, a second temperature sensor 46 is attached to a position approximately in the middle of the indoor heat exchanger 5 . The second temperature sensor 46 has the same function as the third temperature sensor 12 in the first embodiment, so when the indoor heat exchanger 5 is used as an evaporator for room cooling, it detects the evaporation temperature of the refrigerant.

In addition, since other constituent elements are the same as those of the first embodiment, they are given the same reference numerals, and descriptions of their constitutions and functions are omitted. However, as described above, the output temperature and the suction temperature of the refrigerant can be detected by the first sensor 45, so the number of sensors is one less than that of the first embodiment.

Next, the control of the air conditioner will be described.

The control section 18 of the air conditioner of the second embodiment performs the same control as that of the first embodiment. That is, cooling is performed, and based on the temperature difference SH=Tsu−Te detected by the first temperature sensor 45 and the second temperature sensor 46, that is, the degree of superheat, the flow control valve 4 (PMV) is controlled by keeping the degree of superheat SH at a constant value. Superheat control.

Also, when heating the room, based on the output temperature Tt of the refrigerant detected by the first temperature sensor 45, the output temperature control is performed to control the output temperature Tt of the flow regulating valve 4 at a constant value.

Furthermore, compressor 25 (drive motor (shown as 47 among Fig. 2)), control part 18 is corresponding to indoor temperature Ta that the indoor temperature sensor 20 of indoor heat exchanger 5 detects and the temperature Ts that is set by remote controller 19 The difference between the control rotation speed F (the output frequency of the conversion circuit 7), and control corresponding to the air conditioning load.

According to such a configuration, there are effects described below.

First, the air conditioner performs control mainly based on superheat control when cooling, and controls based on output temperature control when heating, so that the first and second advantages described in the first embodiment above can be obtained. The effect is the same.

Second, compared with the first embodiment, the air conditioner of the second embodiment has the effect of room heating or room cooling operation with a small number of sensors.

That is, in the first embodiment, as shown in FIG. 1 , the compressor 1 and the four-way valve 2 are separated, and the output pipe and the suction pipe of the compressor 1 are always the output pipe and the suction pipe when heating or cooling. For this reason, when the room is cooled, the first temperature sensor 10 installed on the suction pipe will detect the suction temperature of the refrigerant, and when the room is heated, the second temperature sensor 11 installed on the output pipe will detect the output temperature of the refrigerant. , must be tested separately.

However, the compressor 25 of the second embodiment is a four-way valve built-in type, so the output side and the suction side can be switched during cooling and heating, and the indoor heat exchanger side piping 37 serves as a suction pipe during cooling and as a suction pipe during heating. The output pipe works.

Therefore, only the first temperature sensor 45 attached to the indoor heat exchanger side piping 37 can detect the intake temperature of the refrigerant during cooling and detect the output temperature of the refrigerant during heating.

Therefore, the number of sensors can be reduced by one if compared with the first embodiment according to the second embodiment. According to this, the control system is simplified, and there is an effect that control can be easily performed.

Furthermore, in the previous compressors described in the previous examples, the superheat control is performed when the room is heated and when the room is cooled, so it is necessary to exchange heat between the suction pipe of the compressor, the outlet pipe, the middle part of the outdoor heat exchanger, and the indoor heat exchanger. A total of 4 temperature sensors are installed in the middle part of the device.

Therefore, according to the second embodiment, if the control is switched between heating and cooling, and the compressor 25 adopts a four-way valve built-in type compressor, there are half of the previous temperature sensor and high-efficiency air-conditioning operation can be performed. Effect.

Also, since the four-way valve built-in type compressor 25 is conventionally connected to the compressor and the four-way valve, it is characterized in that no necessary piping is required, so there is an effect that the piping configuration can be simplified.

In addition, the present invention is not limited to the above-mentioned first and second embodiments, and various modifications can be made within the scope of not changing the gist of the invention.

For example, for the above-mentioned first and second embodiments, the switch valve 2 for switching the refrigerant circulation route is two four-way valves, but not limited thereto, for example, five-way valves are also acceptable.

As mentioned above, in the present invention, for an air conditioner capable of selectively switching between room cooling and room heating operations, the control of the room cooling operation is to control the degree of superheat, and the control of the room heating operation is to control the output temperature.

According to such a configuration, compared with the case of performing the same superheat control during room heating and room cooling, during heating, the indoor heat exchanger that uses the side indoor heat exchanger can be directly controlled, and it is possible to perform Efficient operation.

Also, even when the degree of overheating is not high during room heating, there is an effect that optimum heating operation can be performed.

In addition, when a compressor with a built-in switching valve is used as a compressor that can switch between the suction side and the output side, it is possible to reduce the number of temperature detection devices and perform high-efficiency air conditioning with a simple control method. running effect.

Claims (4)

1. air conditioner has by compressor, indoor heat converter, decompression and connects and composes successively with flow rate regulating valve, outdoor heat converter, also has the kind of refrigeration cycle of the flow channel switching valve of change action direction of flow between room cooling and room heating; It is characterized in that also comprising:

The checkout gear that detects the degree of superheat of the action fluid in above-mentioned indoor heat converter when cooling off in the room is arranged;

The checkout gear that the outlet temperature that detects the action fluid of discharging from above-mentioned compressor when heating in the room is arranged;

Have and be used in room when cooling and reach setting value by the degree of superheat that the checkout gear of the above-mentioned degree of superheat detects, control the aperture of above-mentioned flow rate regulating valve, simultaneously, the detected outlet temperature of checkout gear of above-mentioned outlet temperature reaches setting value when being used in the room heating, controls the control device of the aperture of above-mentioned flow rate regulating valve;

2. air conditioner as claimed in claim 1 is characterized in that also comprising:

The device that the load control compressor rotary speed of corresponding air-conditioning is arranged;

The checkout gear that the outlet temperature that detects the action fluid of discharging from above-mentioned compressor when cooling off in the room is arranged;

Reach design temperature when above in the outlet temperature that detects with checkout gear, stopping to make the degree of superheat is the control of certain value, above-mentioned outlet temperature is lower than the rotating speed that setting value reduces compressor, and above-mentioned outlet temperature is lower than the device that setting value is controlled the aperture of above-mentioned flow rate regulating valve when following;

3. air conditioner, it be a kind ofly have airtight casing, be arranged at high pressure action fluid after will compressing in this casing be full of this airtight casing inside compression unit, be arranged at the swap out compressor of flow channel switching valve of oral-lateral and inlet side of airtight casing inscribe;

Connect and compose successively with flow rate regulating valve, outdoor heat converter by compressor, indoor heat converter, decompression,, switch the outlet side of above-mentioned compressor and the kind of refrigeration cycle that inlet side is selected room heating and room cooling by switching above-mentioned flow channel switching valve; It is characterized in that also comprising:

First temperature-detecting device that is arranged on the pipe arrangement that connects compressor and indoor heat converter is arranged;

Be arranged in the indoor heat converter, detect second temperature-detecting device of the refrigerant temperature in the indoor heat converter;

It is the control device of the above-mentioned flow rate regulating valve aperture of basis control that the refrigerant temperature that detects with first, second temperature-detecting device is arranged;

4. air conditioner as claimed in claim 3 is characterized in that: the control device that the above-mentioned flow rate regulating valve aperture of control is arranged;

When the room cools off, this control device is calculated the degree of superheat according to the suction refrigerant temperature that detects with above-mentioned first temperature-detecting device with the cold-producing medium evaporating temperature that above-mentioned second temperature-detecting device detects, and is the aperture that certain value is controlled above-mentioned flow rate regulating valve for making this degree of superheat;

When the room heated, the discharging refrigerant temperature that this control device detects according to above-mentioned first temperature-detecting device was the aperture of the above-mentioned flow rate regulating valve of certain value ground control for the temperature that makes this discharging refrigerant.

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