JP2002005536A - Heat pump cycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a heat pump cycle wherein temperature in an indoor side heat exchanger is raised by increasing the degree of overheating for a suction refrigerant to be sucked into a compressor to ensure air conditioning control of blowing off high temperature warm air. SOLUTION: A cooling/heating change-over heat pump cycle is adapted to include a compressor 1, an indoor side heat exchanger 3, an outdoor heat exchanger 5, an expansion valve 4, and a four-way valve 2 for flowing a refrigerant from the compressor 1 to the outdoor side heat exchanger 5 upon cooling operation while flowing a refrigerant from the compressor 1 to the indoor side heat exchanger 3 upon heating operation. In the heat pump cycle in air conditioning control of the heating operation, a low pressure refrigerant flowing out of the outside heat exchanger 5 and sucked into the compressor 1, and a high pressure refrigerant flowing out from the indoor side heat exchanger 3 into the expansion valve 4, are heat exchanged through a refrigerant heat exchanger 6 where a heat transfer tube 6a is disposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump cycle for air conditioning capable of performing a cooling operation and a heating operation, and more particularly to an air conditioning control in a heating operation.

[0002]

2. Description of the Related Art In a heat pump cycle for air conditioning, as is well known, a refrigerant is evaporated in an outdoor heat exchanger (evaporator), and the evaporated gas-phase refrigerant is compressed by a compressor. A condenser is used to heat the room. The air-conditioning control of the heating operation is controlled so that when the room temperature reaches the set temperature, the small capacity is controlled and the room temperature is kept constant.

[0003] In the case of a constant-speed compressor, this control generally performs intermittent control of operation / stop of the operation of the compressor and intermittent control of operation / stop of an indoor blower that blows warm air into the room. Air-conditioning control for keeping the room temperature constant by repeating the control, and in the case of a variable compressor, air-conditioning control for keeping the room temperature constant by small-capacity operation by reducing the rotation speed of the compressor are known.

[0004]

However, among the above-mentioned air conditioning controls, the former air conditioning control for interrupting the blowing of warm air causes discomfort due to repeated warm air blowing, stopping or blowing hot air, and repeatedly blowing cold air. . In the latter case, the air conditioning control for lowering the rotation speed of the compressor reduces the condensing capacity to lower the blow-out temperature, increasing the feeling of cool air. Causes deterioration. Furthermore, if the amount of air blown is reduced in order to increase the blowing temperature, there is a problem that the refrigerant is not sufficiently condensed in the indoor heat exchanger and the cycle is not stable.

In view of the above, an object of the present invention is to provide
By increasing the degree of superheat of the refrigerant sucked into the compressor,
An object of the present invention is to provide a heat pump cycle capable of performing air-conditioning control that raises the temperature in an indoor heat exchanger and blows out high-temperature hot air.

[0006]

In order to achieve the above object, the technical means according to claims 1 to 6 are adopted.

That is, according to the first aspect of the present invention, the compressor (1) for compressing the refrigerant, the indoor heat exchanger (3), the outdoor heat exchanger (5), the throttle means (4), and the cooling system A first switching means (1) that allows the compressor (1) to flow from the compressor (1) to the outdoor heat exchanger (5) during operation and the heating operation to flow from the compressor (1) to the indoor heat exchanger (3). 2) In the heat pump cycle capable of switching between cooling and heating, the low-pressure refrigerant flowing out of the outdoor heat exchanger (5) and sucked into the compressor (1) and the indoor heat when performing air conditioning control of the heating operation. It is characterized in that heat is exchanged with the high-pressure refrigerant flowing out of the exchanger (3) and drawn into the throttle means (4).

According to the first aspect of the present invention, when performing the air conditioning control of the heating operation, the low pressure refrigerant flowing out of the outdoor heat exchanger (5) and the high pressure refrigerant flowing out of the indoor heat exchanger (3) are used. , Heat exchange of the indoor heat exchanger (3) with a part of the condensing capacity (heating capacity) of the indoor heat exchanger (3) is deprived of heat exchange with the low-pressure refrigerant. And the low-pressure refrigerant sucked into the compressor (1)
Since the refrigerant is heated by the high-pressure refrigerant, a superheat degree can be given to the low-pressure refrigerant on the suction side of the compressor (1). Therefore, the saturated gas having a high superheat degree due to the ratio of the gas-phase refrigerant in the indoor heat exchanger (3). Since the area increases, the average temperature in the indoor heat exchanger (3) increases, and high-temperature hot air can be blown out.

Therefore, when performing the air conditioning control of the heating operation,
For example, by performing air conditioning control that blows out high-temperature hot air with a small air volume when the room temperature reaches a set temperature,
Compared to the control method by operating / stopping the compressor, air conditioning control of a comfortable heating operation without a feeling of cool air can be performed.

[0010] Further, during the heating operation in which the outside air temperature is low, the degree of superheat tends to be small (the amount of evaporation is small). However, since the refrigerant sucked into the compressor (1) is reliably heated, the liquid phase is reduced. The refrigerant can be prevented from being sucked.

According to the second and third aspects of the present invention, the heat exchange between the low-pressure refrigerant and the high-pressure refrigerant is performed by the heat transfer means (6) for flowing either the low-pressure refrigerant or the high-pressure refrigerant during the heating operation.
a, 16a) and a heat exchange unit (6) that includes the heat transfer means (6a, 16a) and allows the passage of one of a high-pressure refrigerant and a low-pressure refrigerant that is different from the refrigerant flowing through the heat transfer means (6a, 16a). , 16), and the heat exchange section (6, 16) is provided between the outflow side of the outdoor heat exchanger (5) and the suction side of the compressor (1), and One end of the means (6a, 16a) is connected to the outflow side of the indoor heat exchanger (3), and the other end is connected to the suction side of the throttle means (4).

According to the second and third aspects of the present invention, specifically, the heat transfer means (6a, 16a) connected so as to allow the high-pressure refrigerant to flow from the indoor heat exchanger (3) is provided. Heat exchange section (6, 1) including heat transfer means (6a, 16a)
6) is disposed between the outdoor heat exchanger (5) and the suction side of the compressor (1), so that the low-pressure refrigerant on the suction side of the compressor (1) is easily replaced by the high-pressure refrigerant. As a result, the indoor heat exchanger (3) can control a small capacity as described above, and the indoor heat exchanger (3) The average temperature of the refrigerant temperature increases, and high-temperature hot air can be blown out. Therefore, the same operations and effects as described above are achieved.

Further, according to the invention of claim 4, the heat transfer means (6
a, 16a) is disposed between the outflow side of the indoor heat exchanger (3) and the suction side of the throttle means (4), and the heat transfer means (6, 16). 6a, 16a) is characterized in that one end is connected to the outlet side of the outdoor heat exchanger (5) and the other end is connected to the suction side of the compressor (1).

According to the fourth aspect of the present invention, in addition to the above-described structure, the heat transfer means (6a, 16a) connected so as to allow the low-pressure refrigerant to flow from the outdoor heat exchanger (5) is provided. Heat exchange section (6, 16) including heating means (6a, 16a)
Is provided between the indoor heat exchanger (5) and the suction side of the throttle means (4), thereby providing the same operation and effect as described above.

According to the fifth aspect of the present invention, the heat exchange section (6, 1
6) second switching means (8) for switching the high-pressure refrigerant to flow through either the heat transfer means (6a, 16a) or to bypass the heat transfer means (6a, 16a). Temperature detecting means (14) for detecting room temperature;
An air-conditioning control unit (15) for switching the second switching unit (8) according to the detection output of the temperature detection unit (14) is provided.

According to the invention of claim 5, the heat transfer means (6a, 16a) according to the detection output of the temperature detection means (14).
Air-conditioning control means (15) for switching to either one of the following, or to bypass the heat transfer means (6a, 16a).
Therefore, for example, when the room temperature has not reached the set temperature such as at the start of the heating operation, the heating operation is performed by a general heat pump cycle without circulating the refrigerant by bypassing the heat transfer means (6a, 16a). When the room temperature reaches the set temperature, the second switching means (8) allows the refrigerant to flow through the heat transfer means (6a, 16a) and causes the heat exchange section (6,
By exchanging heat between the high-pressure refrigerant and the low-pressure refrigerant in 16), the indoor heat exchanger (3) can control a small capacity and blow out high-temperature hot air, so that the room temperature is set to the set temperature. It is suitable for controlling the capacity when the pressure has reached.

Therefore, high-temperature blown air can be obtained by controlling the amount of air blown to the indoor heat exchanger (3) with a small amount of air. Therefore, as compared with the conventional method of controlling the air flow of the compressor (1) and the indoor side to control the operation / stop of the air flow, the indoor heat exchanger (3) can perform control to obtain high-temperature blown air, Comfortable and good air-conditioning control without the feeling of cool air.

In addition, compared with the conventional method of controlling the small capacity by lowering the rotation speed of the compressor (1), a high-temperature blown air can be obtained as compared with the method of controlling the air conditioning.
Since the heat exchange section (6) and the control means (15) are simple in structure and control, complicated control such as inverter control and various electric devices for varying the power supply voltage are unnecessary, and a low-cost product can be provided. . In the invention of claim 6, the air conditioning control means (15) adjusts the opening degree by the throttle means (4) so that the degree of superheat on the suction side of the compressor (1) is about 20 to 30 ° C. Features.

According to the fourth aspect of the present invention, by setting the degree of superheat on the suction side of the compressor (1) to about 20 to 30 ° C.,
The temperature inside the indoor heat exchanger (3) can be raised without increasing the pressure, and the liquid-phase refrigerant can be prevented from being sucked into the compressor (1).

Note that the reference numerals in parentheses of the above means indicate the correspondence with the concrete means of the embodiment described later.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a heat pump cycle capable of switching between cooling and heating according to the present invention will be described below with reference to FIGS. First, as shown in FIG. 1, in the heat pump cycle of the present invention, reference numeral 1 denotes a compressor for sucking and compressing a refrigerant, and 2 denotes a refrigerant discharged from the compressor 1 in a heating or cooling operation mode. This is a four-way valve that switches between the case of flowing toward the exchanger 3 and the case of flowing toward the outdoor heat exchanger 5. Then, during the heating operation, as shown in FIG. 1, switching is performed so as to circulate from the compressor 1 to the indoor heat exchanger 3.

The indoor heat exchanger 3 exchanges heat between the refrigerant and the indoor air, and functions as an evaporator during a cooling operation and as a condenser during a heating operation. Also,
The outdoor heat exchanger 5 exchanges heat between the refrigerant and the outdoor air, and functions as a condenser during a cooling operation and functions as an evaporator during a heating operation. Reference numeral 3a denotes an indoor blower that takes in indoor air and blows out either the heat of evaporation (cold air) or the heat of condensation (warm air) of the indoor heat exchanger 3 into the room. , And slow 4
The mode switches to the fast air volume mode. 5a is an outdoor blower that takes in outdoor air and blows out the heat of evaporation (cold air) or the heat of condensation (warm air) of the outdoor heat exchanger 5 to the outside.

Reference numeral 4 denotes an expansion valve for reducing the pressure of the high-pressure refrigerant compressed by the compressor 1. The expansion valve arbitrarily controls the degree of valve opening, such as an electronic expansion valve. Reference numeral 6 denotes a refrigerant heat exchanger that exchanges heat between the high-pressure refrigerant flowing out of the indoor heat exchanger 3 and the low-pressure refrigerant flowing out of the outdoor heat exchanger 3 during air-conditioning control (described later) of the heating operation. The high-pressure refrigerant is circulated through the heat transfer tube 6a provided in the refrigerant heat exchanger 6 for circulating the low-pressure refrigerant, and exchanges heat with the low-pressure refrigerant.

Accordingly, one end of the refrigerant heat exchanger 6 is connected to the outflow side of the outdoor heat exchanger 5, and the other end is connected to the side communicating with the suction side of the compressor 1 via the four-way valve 2 and the accumulator 7. ing. One end of one heat transfer tube 6a is connected from the outlet side of the indoor heat exchanger 3 via a three-way valve 8, and the other end is connected to the suction side of the expansion valve 4 via a first check valve 9a. I have. One end of the heat transfer tube 6a is formed on the other end of the refrigerant heat exchanger 6 which communicates with the suction side of the compressor 1, so that the low-pressure refrigerant and the high-pressure refrigerant exchange heat in opposite flows. I have.

The accumulator 7 is provided so as to store surplus refrigerant during the heat pump cycle, separate the refrigerant into a gaseous refrigerant and a liquid-phase refrigerant, and flow the gaseous refrigerant to the suction side of the compressor 1. .

One end of the three-way valve 8 is connected to the outlet side of the indoor heat exchanger 3, one end of the three-way valve 8 is connected to one end of the heat transfer tube 6 a of the refrigerant heat exchanger 6, and the other end is connected to the other end. Is connected to the suction side of the expansion valve 4 via a first bypass passage 10a bypassing the heat transfer tube 6a and a first check valve 9a. In other words, the high-pressure refrigerant introduced from the indoor heat exchanger 3 is passed through the heat transfer tube 6a, and after the heat exchange with the low-pressure refrigerant, is passed through the suction side of the expansion valve 4, or the first bypass bypassing the heat transfer tube 6a. This is a switching valve that switches the flow to the suction side of the expansion valve 4 via the passage 10a.

Here, the three-way valve 8 is circulated through the first bypass passage 10a that bypasses the heat transfer tube 6a at the time of the start of the heating operation (described later), and during air-conditioning control (described later). Switching is performed so as to circulate through the heat transfer tube 6a.

Next, the first check valve 9a and the second check valve 9b are valves that allow the refrigerant to flow only in one direction, and the first check valve 9a operates during the heating operation. It is provided between the suction side of the expansion valve 4 and the first bypass passage 10a communicating with one end of the heat transfer tube 6a so that the refrigerant flowing out of either the heat transfer tube 6a or the three-way valve 8 flows to the expansion valve 4. ing. The second check valve 9b is connected to the expansion valve 4 during the cooling operation.
A second bypass passage 10b is formed so as to bypass the heat transfer tube 6a and the three-way valve 8 and flow to the indoor heat exchanger 3, and is provided in the second bypass passage 10b.

Next, 11 is a pressure sensor, 12 is a refrigerant temperature sensor, which is installed on the outlet side of the refrigerant heat exchanger 6 and detects the degree of superheat of the gas phase refrigerant after passing through the refrigerant heat exchanger 6 during the heating operation. It is for. Reference numeral 13 denotes a blowout temperature sensor for detecting the temperature of blown air blown out of the indoor heat exchanger 3 for preventing cool air having a predetermined temperature or less from being blown into the room. A room temperature sensor 14 detects a room temperature.

These sensor groups 11, 12, 13, 1
4, the detection signal is input to an electric control device (hereinafter referred to as ECU) 15. The ECU 15 inputs signals such as an operation switch (not shown), an operation mode changeover switch, a blow mode changeover switch, and a set temperature switch other than these signals, performs predetermined arithmetic processing in accordance with a preset program, and executes the processing of the compressor 1. Start / stop, four-way valve 2
Switching control, control of the opening degree of the expansion valve 4, the indoor blower 3
It controls the operation of electric equipment such as the air flow control a and the switching control of the three-way valve 8.

The operation mode changeover switch is a switch for selecting one of a heating operation and a cooling operation, and the blower mode changeover switch is used to change the amount of air blown by the indoor blower 3a between high speed, medium speed and low speed. This switch is used to select any air volume mode. The set temperature switch is a selection switch for the user to set a desired room temperature.

Next, the above-described ECU 15 is provided with air-conditioning control means for heating operation based on a control program as shown in FIG. Hereinafter, description will be given according to the control program. First, in step 100, the operation mode is selected to the heating side, and the operation switch is operated to start the heating operation. In step 110, the four-way valve 2 is connected to the indoor heat exchanger 3 by the refrigerant discharged from the compressor 1. Is operated so as to flow toward the heating circuit side, and switching is performed such that the three-way valve 8 flows through the first bypass passage 10a that bypasses the heat transfer tube 6a. As a result, FIG.
A heat pump cycle as shown in FIG.

That is, the refrigerant discharged from the compressor 1 flows into the expansion valve 4 via the first heat exchanger 3 through the first bypass passage 10a, and then flows through the outdoor heat exchanger 5 and the accumulator 7. Thus, a refrigerant circuit to be drawn into the compressor 1 is formed, and the refrigerant is not circulated through the heat transfer tube 6a. Here, when the compressor 1 is operated, the compressed high-pressure refrigerant is circulated to the indoor heat exchanger 3 to start the heating operation. Note that the outdoor blower 5a also operates at a predetermined air volume.

Next, in step 120, a judgment is made between the room temperature sensor 14 for detecting the room temperature and the set temperature set by the user. Specifically, when the difference X between the room temperature and the set temperature is smaller than −T with respect to the predetermined temperature control width T, the process proceeds to step 130. If the temperature control width T is, for example, 0.5 ° C., X <−0.5
When the temperature is ° C, the process proceeds to step 130. Incidentally, when the room temperature has not reached the set temperature, such as when the heating operation starts, the process proceeds to step 130.

Next, at step 130, the indoor side blower 3a is operated in the blow mode selected from the large air volume (high speed, medium speed, and low speed), and the opening degree of the expansion valve 4 is changed by the refrigerant heat exchange. Control is performed by detecting the refrigerant temperature by the refrigerant temperature sensor 12 so that the degree of superheat is in the range of 5 to 10 ° C. on the outlet side of the vessel 6.

At this time, the high-pressure refrigerant flowing out of the indoor heat exchanger 3 communicates with the low-pressure refrigerant on the refrigerant heat exchanger 6 side because of the refrigerant circuit flowing to the expansion valve 4 via the first bypass passage 10a. No heat exchange. Therefore, all the condensing ability of the indoor heat exchanger 3 contributes to indoor heating.

At the time of start-up immediately after the heating operation or the like, since the indoor-side blower 3a does not blow cool air into the room due to the indoor heat exchanger 3 not reaching the predetermined condensation temperature, the blow-out temperature sensor 13 Does not operate until the predetermined temperature is reached. Then, when the blowout temperature sensor 13 reaches a predetermined temperature, warm air is blown into the room, and a heating operation is performed.

Next, when the room temperature rises and reaches the set temperature, the process returns to step 120 to determine the difference between the room temperature and the set temperature. Specifically, the difference X between the room temperature and the set temperature
Is greater than or equal to −T with respect to the predetermined temperature control width T and is equal to or smaller than the predetermined temperature control width T (−T ≦
If X ≦ T, the process proceeds to step 140.

In step 140 (air conditioning control means), first, the three-way valve 8 is switched so as to flow through the heat transfer tube 6a. Then, the indoor-side blower 3a is operated in a small-volume (slow-speed) air-blowing mode, and the degree of opening of the expansion valve 4 is set to 2 at the outflow side of the refrigerant heat exchanger 6.
The control is performed by detecting the refrigerant temperature by the refrigerant temperature sensor 12 so as to be within the range of 0 to 30 ° C.

Thus, a heat pump cycle as shown in FIG. 1 is formed. That is, the indoor heat exchanger 3
The high-pressure refrigerant that has flowed out flows through the heat transfer tube 6a of the refrigerant heat exchanger 6 through which the low-pressure refrigerant that flows out of the outdoor heat exchanger 5 flows, and exchanges heat.
The refrigerant radiated in the step (1) is operated to control the valve opening so that the superheat degree of the gas-phase refrigerant on the outlet side of the refrigerant heat exchanger 6 is in the range of 20 to 30 ° C. In addition, the indoor side blower 3a is operated at a very low speed in order to obtain high-temperature blowing.

Here, the behavior of the cycle in the air-conditioning control means during the heating operation, which is a feature of this embodiment, will be described. On the Mollier diagram (ph diagram) in FIG.
The cycle diagram (ABCD) shown by the broken line shows the behavior of the cycle at the time of start-up in step 130. As is well known, point A indicates the state on the outflow side of the outdoor heat exchanger 5, and point B Indicates a state on the discharge side of the compressor 1, point C indicates a state on the suction side of the expansion valve 4, and point D indicates a state on the suction side of the outdoor heat exchanger 5. Also,
BC indicates the condensation capacity of the indoor heat exchanger 3, and AD indicates the evaporation capacity of the outdoor heat exchanger 5.

Next, a cycle diagram (EF) shown by a solid line
GH) shows the cycle behavior of the air-conditioning control unit in step 140. The heat exchange between the high-pressure refrigerant and the low-pressure refrigerant is performed in the above-described refrigerant heat exchanger 6, and the superheat degree on the outlet side of the refrigerant heat exchanger 6 is increased, so that this characteristic reduces the refrigerant temperature on the discharge side of the compressor 1. In order to increase the enthalpy, the enthalpy on the inlet side of the indoor heat exchanger 3 increases, and the condensing capacity increases.
However, the refrigerant heat exchanger 6 through which the high-pressure refrigerant flows (between J and G)
And the refrigerant heat exchanger 6 (between KE) through which the low-pressure refrigerant flows, the condensing capacity of the indoor heat exchanger 3 is F-F in the figure.
It is between J. This is suitable for air conditioning control when the heat load is small, such as when keeping the room temperature close to the set temperature constant by reducing the condensation capacity of the indoor heat exchanger 3 to a small capacity.

Further, the proportion of the gas-phase refrigerant in the indoor heat exchanger 3 increases the saturated gas region having a high degree of superheat,
The average temperature in the indoor heat exchanger 3 is increased, and by reducing the air volume, high-temperature hot air can be blown into the room.

Further, even if the heat is radiated at a high temperature and a small air volume in the indoor heat exchanger 3, the supercooled liquid-phase refrigerant flows into the suction side of the expansion valve 4 to stabilize the heat pump cycle. Further, when the refrigerant on the suction side of the compressor 1 is added with a degree of superheat, the gas-phase refrigerant is supplied, and the liquid-phase compression is completely eliminated.

Even if the above-described air-conditioning control means controls the room temperature to approach the set temperature, the room temperature may exceed the set temperature under a use environment condition with a small heat load. At this time, the process returns to step 120 to determine the difference between the room temperature and the set temperature. Specifically, when the difference X between the room temperature and the set temperature is larger than T with respect to the predetermined temperature control width T (T <X), the process proceeds to step 150.

In step 150, air-conditioning control is performed so that the compressor 1, the indoor blower 3a, and the outdoor blower 5a are all stopped to prevent the room temperature from rising above the set temperature. Thereafter, the difference between the room temperature and the set temperature is determined in Step 120, and Step 1 is performed.
Step 40 or step 150 is repeated to control the indoor air conditioning.

While the heating mode has been described above as the operation mode, during the cooling operation, as shown in FIG.
Flows toward the outdoor heat exchanger 5, whereby the high-pressure refrigerant discharged from the compressor 1 flows into the expansion valve 4 via the refrigerant heat exchanger 6 and the outdoor heat exchanger 5, and Thus, a refrigerant circuit is formed in which the refrigerant decompressed in the above is sucked into the compressor 1 via the indoor heat exchanger 3 and the accumulator 7 via the second bypass passage 10b. Thus, the indoor heat exchanger 3 functions as an evaporator, and the outdoor evaporator 5 functions as a condenser to cool the room.

In the cooling operation, the three-way valve 8 is switched so as to communicate with the first bypass passage 10a and the suction side of the indoor heat exchanger 3. Therefore, the heat transfer tube 6
Since the refrigerant does not circulate in a, the operation can be performed without hindering the cooling operation.

According to the heat pump cycle of this embodiment, the low-pressure refrigerant flowing out of the outdoor heat exchanger 5 and the indoor heat exchanger 3
Is exchanged with the high-pressure refrigerant flowing out of the heat exchanger, a part of the condensing capacity (heating capacity) of the indoor heat exchanger 3 is deprived of heat exchange with the low-pressure refrigerant. In addition to the control, the low-pressure refrigerant sucked into the compressor 1 is heated by the high-pressure refrigerant, so that the low-pressure refrigerant on the suction side of the compressor 1 is overheated. , The average temperature of the refrigerant in the indoor heat exchanger 3 increases, and high-temperature hot air can be blown out.

Therefore, when performing the air conditioning control of the heating operation,
For example, by performing air conditioning control that blows out high-temperature hot air with a small air volume when the room temperature reaches a set temperature,
Compared to the control method by operating / stopping the compressor, air conditioning control of a comfortable heating operation without a feeling of cool air can be performed.

In the heating operation in which the outside air temperature is low, the degree of superheat tends to be small (the amount of evaporation is small), but the refrigerant heat exchanger 6 surely heats the refrigerant sucked into the compressor 1. Accordingly, the liquid refrigerant can be prevented from being sucked.

A three-way valve 8 is provided upstream of the flow circuit of the heat transfer tube 6a and a first check valve 9a is provided downstream of the heat transfer tube 6a, so that the refrigerant flows only during the air conditioning control of the heating operation. It can be operated at the time of startup and without hindering the cooling operation.

Further, compared with the conventional system in which the rotation speed of the compressor 1 is reduced to control the small capacity and the air conditioning is controlled, a high-temperature blown air can be obtained, and the structure and control are simple. Since the refrigerant heat exchanger 6 and the air conditioning control means can cope with the above, complicated control such as inverter control and various electric devices for varying the power supply voltage are not required, and a low-cost product can be provided.

(Other Embodiments) In the above embodiment,
Although the first check valve 9a is provided between the suction side of the expansion valve 4 and the first bypass passage 10a communicating with one end of the heat transfer tube 6a, as shown in FIG. It may be provided that the refrigerant flows toward the suction side of the expansion valve 4 before intersecting with one end of the first bypass passage 10 a with the valve 4.

The switching control of the three-way valve 8 according to this configuration is performed when the air-conditioning control of the heating operation is performed, that is, when the room temperature reaches the set temperature, the switching control is performed so as to flow through the heat transfer pipe 6a. The switching control is performed so as to bypass the heat transfer tube 16a when the room temperature does not reach the set temperature, such as when the air conditioner rises, and during the cooling operation.

According to the above configuration, since the second check valve 9b and the second bypass passage 10b are not required, the cost of parts can be reduced.

In the above embodiment, the heat transfer tubes 6a
Is installed between the outflow side of the outdoor heat exchanger 5 and the suction side of the compressor 1 by controlling the air conditioning control of the heating operation with the refrigerant heat exchanger 6 provided therein. It has been described that the high-pressure refrigerant flows through the heat transfer tube 6a.
May be installed on the outflow side of the indoor heat exchanger 3.

As shown in FIG. 7, one end of the three-way valve 8 is connected to the outlet side of the outdoor heat exchanger 5 and one of the other ends is connected to the second end.
Is connected to one end of a second heat transfer tube 16 a of the refrigerant heat exchanger 16, and the other end is connected to communicate with the suction side of the compressor 1. One end of the second refrigerant heat exchanger 16 is connected to the outflow side of the indoor heat exchanger 3 and the other end is connected to the suction side of the expansion valve 4.
One end of the three-way valve 8 is connected to one of the other ends of the three-way valve 8, and the other end is connected to the other end of the other end of the three-way valve 8 via the first check valve 9a. The three-way valve 8 is
When performing the air conditioning control of the heating operation, that is, when the room temperature reaches the set temperature, the switching control is performed so as to flow through the second heat transfer tube 16a, and the room temperature such as at the start of the heating operation does not reach the set temperature. And the second heat transfer tube 1 during cooling operation.
Switching control is performed so as to bypass 6a.

According to the above configuration, heat exchange between the high-pressure refrigerant and the low-pressure refrigerant can be performed in the second refrigerant heat exchanger 16. Therefore, the same operations and effects as those of the embodiment are achieved.

Further, according to this configuration, the second check valve 9
b and the second bypass passage 10b can be dispensed with, so that the cost of parts can be reduced.

In the above embodiment, the operation mode changeover switch and the ventilation mode changeover switch have been described by the manual operation. However, the present invention is not limited to this.
The operation mode and the air blowing mode may be automatically controlled by the ECU 15 by inputting the input signal of No. 4.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a refrigerant flow in a heat pump cycle in a heating operation according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an air conditioning control unit according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a refrigerant flow in a heat pump cycle in a heating operation according to one embodiment of the present invention.

FIG. 4 is a cycle diagram showing a heat pump cycle in one embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a refrigerant flow in a heat pump cycle in a cooling operation according to one embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a refrigerant flow in a heat pump cycle in a heating operation according to another embodiment.

FIG. 7 is an explanatory diagram showing a refrigerant flow in a heat pump cycle of a heating operation in another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Compressor 2 ... Four-way valve (1st switching means) 3 ... Indoor heat exchanger 4 ... Expansion valve (throttle means) 5 ... Outdoor heat exchanger 6 ... Refrigerant heat exchanger (heat exchange part) 6a ... Heat transfer tube (heat transfer means) 8 ... three-way valve (second switching means) 14 ... indoor temperature sensor (temperature detection means) 15 ... electric control device (air conditioning control means) 16 ... second refrigerant heat exchanger (heat exchange) Part) 16a: second heat transfer tube (heat transfer means)

Claims (6)

[Claims] A compressor (1) for compressing a refrigerant, and an indoor heat exchanger (3) disposed indoors and air-conditioning the indoors.
A throttle means (4) installed between an outdoor heat exchanger (5) arranged outdoors and the heat exchangers (3, 5); and a compressor (1) for cooling operation. The discharged refrigerant discharged is circulated to the outdoor heat exchanger (5), and the refrigerant discharged from the compressor (1) is circulated to the indoor heat exchanger (3) during the heating operation. In the heat pump cycle capable of switching between cooling and heating, the first switching means (2) for controlling the air conditioner to perform air conditioning control for heating operation, flows out of the outdoor heat exchanger (5) and flows to the compressor (1). A heat pump cycle characterized in that heat is exchanged between the sucked low-pressure refrigerant and the high-pressure refrigerant flowing out of the indoor heat exchanger (3) and drawn into the throttle means (4). 2. The heat exchange between the low-pressure refrigerant and the high-pressure refrigerant is performed by a heat transfer means (6a, 16) for flowing one of the low-pressure refrigerant and the high-pressure refrigerant during a heating operation.
a) and heat exchange in which either the high-pressure refrigerant or the low-pressure refrigerant, which is different from the refrigerant provided with the heat transfer means (6a, 16a) and passed through the heat transfer means (6a, 16a), flows. The heat pump cycle according to claim 1, wherein the heat pump cycle is performed between the heat pump cycle and the heat pump cycle. 3. The heat exchange section (6, 16) provided with the heat transfer means (6a, 16a) is connected to an outflow side of the outdoor heat exchanger (5) and suction of the compressor (1). And one end of the heat transfer means (6a, 16a) is connected to the outlet side of the indoor heat exchanger (3), and the other end is connected to the suction side of the throttle means (4). The heat pump cycle according to claim 2, wherein the heat pump cycle is configured to be connected. 4. The heat exchange section (6, 16) provided with the heat transfer means (6a, 16a) is connected to the outlet side of the indoor heat exchanger (3) and the suction of the throttle means (4). And one end of the heat transfer means (6a, 16a) is connected to the outlet side of the outdoor heat exchanger (5), and the other end is connected to the suction side of the compressor (1). The heat pump cycle according to claim 2, wherein the heat pump cycle is configured to be connected. 5. The heat exchange section (6, 16) is provided via the heat transfer means (6a, 16a) or the heat transfer means (6, 16a).
a switching means (8) for switching the high-pressure refrigerant to flow through any one of the bypass means (a, 16a).
A temperature detection unit (14) for detecting a room temperature; and an air conditioning control unit (15) for switching the second switching unit (8) in accordance with a detection output of the temperature detection unit (14). Any one of claims 1 to 4
The heat pump cycle according to the paragraph. 6. The air-conditioning control means (15) controls the degree of opening by the throttling means (4) such that the degree of superheat on the suction side of the compressor (1) is about 20 to 30 ° C. The heat pump cycle according to claim 5, wherein