JPH0432304B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field) The present invention relates to a separate heating and cooling system, and more specifically, an outdoor unit equipped with a compressor, a four-way switching valve, and a heat exchanger on the heat source side, and an indoor unit equipped with a heat exchanger on the user side are connected. Related to separate air conditioning and heating equipment. (Prior Art) It has been known to perform low pressure control and high pressure control, respectively, in cooling devices and heating devices using refrigerant circuits. For example, it is described in Utility Model Publication No. 46-14440,
As schematically shown in FIG. 3, a refrigerant circuit is formed by sequentially connecting a compressor 50, a heat source side heat exchanger 51, a liquid receiver 52, a cooling expansion valve 53, a user side heat exchanger 54, and an accumulator 55. In the cooling system, in order to perform low pressure control, the gas region of the liquid receiver 52 and the accumulator 55 are connected to the hot gas bypass pipe 5.
6, a low pressure detection pipe 57 is connected to this pipe 56, and a low pressure control valve 58 is interposed to mechanically adjust (increase) the valve opening degree according to changes (decrease) in suction gas pressure. something is known. Also, it is described in Utility Model Publication No. 51-37266, and
As shown in the figure, in the heating system, a hot gas bypass pipe 5 connects the gas region of the liquid receiver 52 and the accumulator 55, similar to that shown in FIG.
Unlike the one shown in FIG. 3, a high-pressure control valve is provided which connects a high-pressure outlet pipe 59 to the pipe 56 and adjusts (increases) the valve opening according to a change (increase) in the condensing pressure. 60 is known. In FIG. 4, reference numeral 61 denotes a heating expansion valve, and other components indicated by the same reference numerals as in FIG. 3 indicate the same configuration as shown in FIG. 3. However, the valves shown in FIGS. 3 and 4 use valves in which low pressure or high pressure is applied directly to each control valve 58, 60 to mechanically control the valve opening degree. In detail, each of the control valves 58,
For example, the valve 60 is provided with a setting spring (not shown) that sets a lower limit of the low pressure or an upper limit of the high pressure, and counteracts the pushing force of this spring with the pushing force of the low pressure or the high pressure. Since the valve opening was adjusted, it was not possible to perform both low pressure control and high pressure control using one control valve 58 or 60. Therefore, in conventional air-conditioning and heating systems that are capable of both cooling and heating operations, in order to perform low-pressure control during cooling operation and high-pressure control during heating operation, the control valves have to be used for low-pressure control and high-pressure control. This resulted in the problem of complicating the refrigerant circuit. (Object of the Invention) In view of the above-mentioned conventional problems, the present invention has been devised to solve this problem, especially in a separate air-conditioning system consisting of an outdoor unit and an indoor unit. In addition to using an electrically operated valve that can adjust the valve opening automatically, the valve opening of the valve is controlled based on the saturation temperature equivalent to high pressure pressure (condensation temperature) and the saturation temperature equivalent to low pressure pressure (evaporation temperature). In other words, the detection element for high pressure/low pressure control is replaced with pressure, the configuration of the detection section is relatively simple, and the detection element is changed to temperature, while a detection circuit is provided on the outdoor unit side to detect each saturation temperature. By arranging all the wiring for transmitting detection signals connecting each of the detection parts and the electric valve in the outdoor unit, high pressure and low pressure control can be performed in one while maintaining a simple overall configuration. The main point is that it can be done with just one electric valve. (Structure of the Invention) Therefore, the structure of the present invention is such that an indoor unit equipped with a user side heat exchanger is connected to an outdoor unit equipped with a compressor, a heat source side heat exchanger, and a four-way switching valve. In this separate type air-conditioning system, a detection heat exchanger and a pressure reduction mechanism that act as a condenser are interposed between the discharge gas pipe and the suction gas pipe connected to the compressor, and a detection heat exchanger and a pressure reduction mechanism are interposed between the discharge gas pipe and the suction gas pipe connected to the compressor. A detection circuit capable of detecting a pressure-equivalent saturation temperature is interposed, and a first temperature detector is provided on the inlet side of the pressure reducing mechanism in this detection circuit, and a second temperature detector is provided on the outlet side. A hot gas bypass pipe having an electric valve whose opening degree is controlled based on the output from each of the temperature detectors is interposed between the discharge gas pipe and the suction gas pipe, and the opening degree of one of the electric valves is controlled. is controlled based on the saturation temperature corresponding to the high pressure detected by the detection circuit, thereby controlling the high pressure, and
It has been made possible to perform low pressure control by controlling based on the saturation temperature equivalent to the low pressure pressure. (Example) Hereinafter, an example of the present invention will be described based on the drawings. The one shown in FIG. 1 is a separate type air-conditioning and heating system that is composed of an outdoor unit A and an indoor unit B, and is capable of air-conditioning and heating operation. The outdoor unit A is equipped with a compressor 1, a heat source side heat exchanger 2, and an expansion valve 3 that functions as an expansion mechanism for cooling or heating.In order to configure these devices into a reversible cycle, a four-way switching valve 4 is installed. The connection is made as shown below. That is, the discharge gas pipe 5 and the suction gas pipe 6 connected to the compressor 1 are respectively connected to a pair of fixed ports of the four-way switching valve 4, and the pair of switching ports of the four-way switching valve 4 are connected to the A connecting pipe 7 connected to one entrance and exit of the heat source side heat exchanger 2 and a gas pipe 8 connected to one connecting side of the indoor unit B are respectively connected. Further, a liquid pipe 9 serving as the other connection side of the indoor unit B is connected to the other entrance/exit of the heat source side heat exchanger 2, and the expansion valve 3 is interposed in this liquid pipe 9. Moreover, the indoor unit B has a user-side heat exchanger 10.
The user-side heat exchanger 10 is connected to the gas pipe 8 and liquid pipe 9 in the outdoor unit A via a pair of communication pipes 30 to form a refrigerant circuit. In the outdoor unit A, 11 is a liquid receiver, and 12 is an accumulator. In order to perform high-pressure and low-pressure control in the separated air-conditioning and heating system configured in this way, firstly, the hot gas bypass pipe 13 for circulating hot gas from the high-pressure side to the low-pressure side is connected to the discharge gas pipe 5 and the intake gas. In addition to being connected to the pipe 6,
This bypass pipe 13 is provided with an electric valve 14 that adjusts the bypass amount of hot gas. Further, in detail about this electric valve 14, the valve 14 is equipped with a stepper motor and is configured to be able to control the opening degree using an electric signal. Second, the heat source side heat exchange is performed between the inlet/outlet side of the bypass pipe 13 communicating with the discharge gas pipe 5 and the compressor 1 side from the connection point of the bypass pipe 13 in the suction gas pipe 6. A detection circuit 17 is installed in parallel with the detection circuit 17 and sequentially includes a detection heat exchanger 15 acting as a condenser and a pressure reduction mechanism 16 consisting of a capillary reach tube. The discharge gas refrigerant is condensed at the same pressure as the discharge gas pressure (high pressure), and the condensed liquid refrigerant is transferred to the outlet side (suction gas pipe 6 side) of the pressure reducing mechanism 16 at the suction gas pressure (low pressure). and thirdly, a first temperature control device comprising a thermistor on the outlet side of the heat exchanger 15 in the detection circuit 17 and on the inlet side of the pressure reduction mechanism 16. A detector 18 is attached, and a second temperature detector 19 also made of a thermistor is attached on the outlet side of the pressure reducing mechanism 16, and these detectors 18 and 19 measure the saturation temperature (condensation temperature) corresponding to high pressure, respectively. Made to detect the saturation temperature (evaporation temperature) equivalent to low pressure pressure,
Furthermore, fourthly, the first and second temperature detectors 18, 19
and the electric valve 14 are connected by signal transmission wiring, and the opening degree of the electric valve 14 is controlled by the outputs of the respective detectors 18 and 19. Specifically, the outputs from the respective detectors 18 and 19 are input to the motor-operated valve 14, and the motor-operated valve 1
4, a controller K that outputs a signal for controlling the opening degree.
is attached. Then, a set saturation temperature corresponding to the set upper limit pressure of the high pressure and a set saturation temperature corresponding to the set lower limit pressure of the low pressure are input into this controller, so that only the first temperature detector 18 is operated during heating operation. The actual high-pressure equivalent saturation temperature is compared with the set saturation temperature based on the output of the detector 18, and the opening of the electric valve 14 is controlled based on this comparison signal.
Further, during cooling operation, only the second temperature detector 19 is operated to control the opening degree of the electric valve 14 in the same manner. Furthermore, in this embodiment, the expansion valve 3 is also an electric valve whose opening degree can be electrically controlled. Sometimes, the degree of superheating of the suction gas is controlled to be constant. Specifically, firstly, the expansion valve 3 is equipped with a stepper motor (not shown) like the electric valve 14, and the opening degree can be controlled by an electric signal, and secondly, the degree of supercooling, In order to detect the degree of heating by directly detecting the refrigerant temperature, the first and second temperature detectors 18 and 19 are used, and in addition to these,
A third sensor for detecting the temperature of the condensed liquid refrigerant on the outlet side (liquid pipe 9 side) of the user-side heat exchanger 10 during heating operation.
A temperature detector 20 is attached to the indoor unit B side of the expansion valve 3 in the liquid pipe 9, and a fourth temperature detector 21 for detecting the intake gas temperature during cooling operation is attached to the side of the indoor unit B in the intake gas pipe 6. The connection point with the hot gas bypass pipe 13 and the detection circuit 17
It is attached between the connection point and the connection point. Thirdly, the first to fourth temperature detectors 18 to 21 and the expansion valve 3 are connected by wiring for signal transmission. Thus, during heating operation, the first and third temperature detectors 18 and 20 are activated to detect the saturation temperature corresponding to high pressure and the temperature of the condensate refrigerant to detect the degree of supercooling, and this detection signal The opening degree of the expansion valve 3 is controlled so that the degree of supercooling is kept constant based on
Also, during cooling operation, the second and fourth temperature detectors 1
9 and 21 to detect the saturation temperature equivalent to the low pressure pressure and the intake gas temperature to detect the degree of superheating of the intake gas, and based on this detection signal, the It is configured to control the opening degree of the expansion valve 3. Note that the expansion valve 3 is also provided with a controller L similar to that of the electric valve 14. The operation of the separate heating and cooling system configured as described above will now be explained. First, the heating operation will be explained. By switching the four-way switching valve 4, a refrigerant circuit is formed as shown by the solid line A in FIG. When the compressor 1 is driven in this way, the refrigerant is discharged from the compressor 1 as a high-pressure gas refrigerant, reaches the user-side heat exchanger 10 via the four-way switching valve 4, and is condensed to become a high-pressure refrigerant. The refrigerant is further depressurized by the expansion valve 3, becomes a low-pressure liquid refrigerant, reaches the heat source side heat exchanger 2, evaporates there, and flows into the compressor 1 again via the four-way switching valve 4. A heating effect is produced in the user-side heat exchanger 10. On the other hand, high-pressure gas refrigerant also flows into the detection circuit 17 from the discharge gas pipe 5, and this high-pressure gas refrigerant is condensed in the detection heat exchanger 15 at the same pressure as the high pressure (discharge pressure), and becomes liquid. It becomes a refrigerant and reaches the pressure reducing mechanism 16, and is depressurized to the pressure reducing mechanism 16.
On the outlet side of the refrigerant, it evaporates at the same pressure as the low pressure (suction gas pressure), becomes a low pressure gas refrigerant, and flows into the suction gas pipe 6. In addition, during heating operation, as described above, by inputting the outputs of the first and third temperature detectors 18 and 20 to the expansion valve 3, the valve 3 is connected to the outlet side of the utilization side heat exchanger 10. It acts to keep the degree of subcooling of the condensate refrigerant constant. Therefore, during heating operation, the first temperature detector 18
input the output to the electric valve 14, and
When the high pressure becomes equal to or higher than the set upper limit pressure due to a decrease in the heating load, the condensation temperature of the refrigerant in the detection heat exchanger 15 also becomes equal to or higher than the set saturation temperature. As a result, the electric valve 14 operates in the opening direction based on the output of the first temperature detector 18, and the hot gas flows through the hot gas bypass pipe 13 to the discharge gas pipe 5.
It flows out into the suction gas pipe 6 from there. and,
This makes it possible to maintain the high pressure below the set upper limit pressure. Next, the cooling operation will be explained. By switching the four-way switching valve 4, a refrigerant circuit is formed as shown by the dotted arrow B in FIG. Thus, when the compressor 1 is driven, the refrigerant circulates through the four-way switching valve 4 in a cycle opposite to that during heating operation, and a cooling effect is produced in the user-side heat exchanger 10. On the other hand, the refrigerant flows through the detection circuit 17, as shown by the dotted arrow in FIG. 1, in exactly the same manner as during heating operation. Also, during cooling operation, as mentioned above, the second
The output of the fourth temperature detector 19, 21 is connected to the expansion valve 3.
By acting on the valve 3, the valve 3 acts to keep the degree of superheat of the suction gas constant. During this cooling operation, the output of the second temperature detector 19 is applied to the electric valve 14, so that when the low pressure falls below the set lower limit pressure due to a decrease in the cooling load, etc., it is possible to respond to this. Then, the evaporation temperature of the refrigerant at the outlet side of the pressure reducing mechanism 16 in the detection circuit 7 also decreases below the set saturation temperature, and as a result, the electric valve 14 is opened based on the output of the second temperature detector 19. The hot gas flows out from the discharge gas pipe 5 into the suction gas pipe 6 via the hot gas bypass 13.
This allows the low pressure to be maintained above the set lower limit pressure. As described above, according to this embodiment, firstly, high pressure control and low pressure control can be performed using one electric valve 14, and secondly, the opening degree control of the electric valve 14 can be performed depending on the refrigerant temperature. Specifically, since this can be done by detecting the saturation temperature equivalent to high pressure pressure or the saturation temperature equivalent to low pressure pressure, the detectors 18 and 19 can be configured much more simply than in the case of detecting pressure. Thirdly, since each of the above temperatures can be detected in the outdoor unit A without being detected in the user-side heat exchanger 10 of the indoor unit B, the first and second temperature detectors 18 ,19
The wiring for signal transmission connecting the electric valve 14 and the electric valve 14 can be placed entirely within the indoor unit A without the need for wiring between the outdoor and indoor units A and B. This makes work easier, and while the structure is simple overall,
High pressure and low pressure control can be performed with one electric valve 14. Further, according to this embodiment, as described above, in the outdoor unit A, the saturation temperature corresponding to high pressure pressure and the saturation temperature corresponding to low pressure pressure can be detected. While detecting the degree of subcooling of the refrigerant and the degree of superheating of the suction gas, each temperature detector 18 to 2
1 and the expansion valve 3 can all be provided within the outdoor unit A. Therefore, the wiring work is easy in this respect as well. A second embodiment of the present invention will be described below with reference to FIG. What is shown in Figure 2 is one outdoor unit A.
Three indoor units B, C, and D are connected in parallel, and a hot water supply unit E is also connected, so that in addition to cooling and heating operations, cooling and hot water supply operations and hot water supply operations can be performed. Hereinafter, after explaining the main circuit for performing each operation, the configuration of the detection circuit will be explained. In the outdoor unit A, 1 is a compressor, 2 is a heat exchanger on the heat source side, 11 is a liquid receiver, 3 is an electric expansion valve, and SV ₁ and SV ₁ are refrigerant circuits for each of the above operations. 22 is a check valve that allows the refrigerant to flow only during cooling operation, 70 is an electric expansion valve that is activated during heating operation and hot water supply operation, and 23 is also activated only during hot water supply/heating operation. 24 is an on-off valve that opens only during defrost operation, 25 is an on-off valve, 81 is a gas side branch pipe, and 91 is a liquid side branch pipe. Further, 10 is a user-side heat exchanger provided in the indoor units B, C, and D, and 26 is a hot water supply heat exchanger provided in the hot water supply unit E. It should be noted that other reference numerals shown in FIG. 2 having the same reference numerals as those shown in FIG. 1 of the first embodiment each indicate the same structure as the first embodiment. Therefore, as shown in Table 1, the four-way switching valve
SV ₁ and SV ₂ are switched, each on-off valve 24 is opened and closed, and each expansion valve 3 and expansion valve 70 are operated as a superheat degree control (hereinafter referred to as SH) valve, or Depending on whether it is used as a supercooling control (hereinafter referred to as SC) valve,
Can drive on the street.

[Table] Four-way switching valves SV ₁ and SV ₂ communicate with the piping on the dotted line side in Figure 2 when energized (ON), and when de-energized (OFF).
This connects the piping on the solid line side in Figure 2. Further, each on-off valve 24 is of an energized (ON) open type. Further, in Table 1, the numbers shown for each expansion valve 3, 70, for example 19-21, indicate a temperature detector to be described later. In Fig. 2, the solid line arrow C indicates the refrigerant circuit during cooling operation, the dotted line arrow D indicates the cooling/hot water supply operation, the dashed line arrow H indicates the hot water supply operation, and the double dotted line arrow indicates the refrigerant circuit during heating operation. It shows. Incidentally, by closing each of the expansion valves 3 separately, each of the indoor units B, C, and D can be stopped. In the separate type air-conditioning and heating system configured as described above, basically the same as in the first embodiment, firstly, the discharge gas pipe 5 connected to the compressor 1 is
A hot gas bypass pipe 13 with an electric valve 14 interposed between the intake gas pipe 6 and the intake gas pipe 6 is provided, and secondly, a detection heat exchanger 15 and a pressure reducing mechanism 16 consisting of a capillary tube are provided. A circuit 17 is connected between the inlet side of the bypass pipe 13 communicating with the discharge gas pipe 5 and the suction gas pipe 6. Thirdly, the detection heat exchanger in the detection circuit 17 15 and the outlet side of the pressure reducing mechanism 16, first and second temperature detectors 18 and 19 are provided, respectively.
Fourthly, these temperature detectors 18, 19 and the electric valve 14 are electrically connected. Furthermore, in this embodiment, during cooling operation and cooling hot water supply operation, the degree of superheating of the suction gas is controlled for each indoor unit B by the expansion valve 3, and during heating operation, the expansion valve 3 similarly controls the degree of superheating of the suction gas. At the same time, the expansion valve 70
In order to control the degree of superheating of the suction gas, and to control the degree of superheat of the suction gas by operating only the expansion valve 70 during hot water supply operation, the following arrangement is made. That is, in addition to the first and second temperature detectors 18 and 19, the expansion valve 3 in each liquid side branch pipe 91
Each third temperature detector 20 is installed on the indoor unit B side of
Further, each fourth temperature detector 2 is installed in each gas side branch pipe 81.
1 is attached to electrically connect each of the expansion valves 3 and the first to fourth temperature detectors 18 to 21, respectively, while acting on the suction gas pipe 6 during heating/hot water supply operation to detect the suction gas. A fifth temperature detector 71 for detecting temperature is provided, and the expansion valve 70 and the second and fifth temperature detectors 19 and 71 are electrically connected. The liquid receiver 11 uses a liquid pipe 9 between these valves 3 and 70 to simultaneously control the openings of the expansion valve 3 and the electric valve 14 during heating operation by changing the amount of stored liquid refrigerant. , 91, and a bypass pipe connecting the gas region and the low pressure side of the liquid receiver 11 and having a capillary reach tube 27 interposed therein. Reference numeral 28 forms a gas venting passageway for making it possible to increase or decrease the amount of refrigerant stored in the liquid receiver 11. In the above embodiment, the electric valve 14 is equipped with a stepper motor, but a thermoelectric valve as described in Japanese Patent Publication No. 55-143362 or Japanese Patent Application Laid-Open No. 53-1352 may be used. It is also possible to use a solenoid described in the publication. (Effects of the Invention) As described above, the present invention provides a detection heat exchanger 15 that functions as a condenser and a pressure reducing mechanism 1 that is connected to the compressor 1 between the discharge gas pipe 5 and the suction gas pipe 6.
A first temperature detector 18 is installed on the inlet side of the decompression mechanism 16 in the detection circuit 17, and a detection circuit 17 is installed in which the detection circuit 17 is capable of detecting the saturation temperature equivalent to high pressure and the saturation temperature equivalent to low pressure. In addition, a second temperature detector 19 is provided on the outlet side, and the opening degree is controlled between the discharge gas pipe 5 and the suction gas pipe 6 based on the output from each of the temperature detectors 18 and 19. Since the hot gas bypass pipe 13 is provided with an electric valve 14 that performs Specifically, this can be done by detecting the saturation temperature equivalent to high pressure pressure or the saturation temperature equivalent to low pressure pressure, so the configuration of each of the temperature detectors 18 and 19 is significantly simpler than in the case of detecting pressure. Furthermore, since each temperature can be detected in the outdoor unit A without being detected in the user-side heat exchanger 10 of the indoor unit B, the first and second temperature detectors 18 ,19
All wiring for signal transmission connecting the electric valve 14 and the electric valve 14 can be done within the outdoor unit A, and therefore, piping work can be done easily.
Although the overall structure is simple, high pressure and low pressure control can be performed with one electric valve 14.

[Brief explanation of drawings]

FIG. 1 is a refrigerant circuit diagram showing an embodiment of the present invention, FIG. 2 is a refrigerant circuit diagram showing another embodiment, and FIGS. 3 and 4 are refrigerant circuit diagrams showing conventional examples. 1...Compressor, 2...Heat source side heat exchanger, 4...
Four-way switching valve, 5...Discharge gas pipe, 6...Suction gas pipe, 13...Hot gas bypass path, 14...Electric valve, 15...Detection heat exchanger, 16...Pressure reduction mechanism, 17... ...Detection circuit, 18...First temperature detector, 19...Second temperature detector, A...Outdoor unit, B, C, D...Indoor unit.

Claims (1)

[Claims] 1 Compressor 1, heat source side heat exchanger 2, four-way switching valve 4
The user-side heat exchanger 1 is installed in outdoor unit A equipped with
In the separate type air-conditioning system, which is formed by connecting an indoor unit B equipped with 0, a detection heat exchanger 15 serving as a condenser is provided between the discharge gas pipe 5 and the suction gas pipe 6 connected to the compressor 1. and pressure reduction mechanism 16
A detection circuit 17 capable of detecting a saturation temperature equivalent to high pressure pressure and a saturation temperature equivalent to low pressure pressure is interposed, and the pressure reducing mechanism 1 in this detection circuit 17 is
A first temperature detector 18 and a second temperature detector 19 are provided on the inlet side of the gas pipe 6 and a second temperature detector 19 on the outlet side, respectively, and each of the temperature detectors is provided between the discharge gas pipe 5 and the suction gas pipe 6. A separate heating and cooling system characterized in that a hot gas bypass pipe 13 having an electric valve 14 whose opening degree is controlled by the outputs from the air conditioners 18 and 19 is installed.