JPH03113247A - Multi-refrigeration cycle - Google Patents

Abstract

PURPOSE:To automatically control temperatures in rooms separately to desired values by independently controlling the opening of room heat exchange expansion valves based upon deviations between room temperatures and desired values of the formers, and further controlling the openings of outdoor heat exchange expansion valves based upon deviations between the degree of excess heating of gas refrigerations on the discharge side of a compressor and an expectation value of the former. CONSTITUTION:In cooling operation, refrigerant gas from a compressor 1 passes through a four-way valve 2 as indicated by a dotted line, and is condensed and liquefied in an outdoor heat exchanger 3, and further are slightly reduced in pressure by an expansion valve 4. Then, it passes through capillary tubes 5a-5c where it is further reduced in its pressure to form intermediate pressure. Refrigerant side pressure of a room heat exchanger 6a is controlled by an expansion valve 7a, i.e., the opening of the same is adjusted to provide set room temperature. Also for other room heat exchangers 6b, 6c opening of expansion valves 7b, 7c are performed. The refrigerant flows together after vaporization to some degree, and passes through the four-way valve 2 and enters an accumulator 8 and is sucked into the compressor 1.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a single compressor with a plurality of indoor heat exchangers in parallel to improve the comfort of all rooms in a multi-air conditioner.
This article relates to a multi-refrigeration cycle that automatically controls individual room temperatures, greatly easing restrictions on hemming construction.

[Conventional technology]

As described in Japanese Unexamined Patent Publication No. 58-156164, the conventional device increases or decreases the flow rate of refrigerant flowing into each indoor heat exchanger to adjust the heating and cooling capacity for that room to the desired room temperature. do. Depending on the deviation between the actual room temperature of each room and its desired value,
An electronic expansion valve was installed in series with each indoor heat exchanger and controlled once.

[Problem to be solved by the invention]

Conventionally, multi-type air conditioners have a desired room temperature of Kgl1 for each room.
It does not have a function to adjust the temperature, and if there are few indoor units in operation, there are often complaints about it getting too cold or overcooked. In addition, in order to make the flow of refrigerant to each indoor unit uniform, there are many construction restrictions.In the end, these problems are caused by the air conditioner itself being able to detect the temperature of 6 degrees from moment to moment and increase its capacity accordingly. [Means to solve the problem] As a means of individual automatic temperature control, the pressure on the refrigerant side of the indoor heat exchanger is controlled, and the saturation temperature of the refrigerant at that time is controlled. This change controls the amount of heat exchanged with the air. Therefore, during cooling, the control of the low pressure section is roughly divided into two parts: the low pressure in the indoor heat exchanger (referred to as intermediate pressure) and the suction pressure of the compressor. During heating, control of the high pressure section is similarly divided into two parts: compressor discharge pressure and indoor heat exchanger (
This is the internal pressure (intermediate pressure) of the condenser).

This intermediate pressure is adjusted using an electronic expansion valve to adjust the room temperature in each chamber to the set room temperature.

[Effect]

Each indoor heat exchanger is connected in series with a cavity and an electronic expansion valve at both ends, and both cooling and heating depend on the opening degree of the electronic expansion valve and the deviation between the room temperature of the corresponding room and the set room temperature. increase or decrease.

As a result, the refrigerant temperature of the heat exchanger (corresponding to its pressure, 7F, Ba'40 temperature) is automatically adjusted to the cooling and heating capacity (heat exchanger) necessary to reach the desired room temperature. Adjusted ML.

The expansion valves V□, V, ,V in FIG. 1 are controlled by a microcomputer according to the following equation. That is, V, 17) opening correction amount Δvi(
(per period) is ・・・・・・・・・・・・(1) However, Δ#i! #i −”i]slE'rΔVix
k, j Δ#i-y Δ#i+,'Δ#4, I-
P-, (2) However, at that time, the opening degree of the expansion valve v4 in FIG. ' is controlled to be 1
The correction amount Δv4 per period is determined by the following equation. That is, ΔV, -□
1 di for Δ8Hd+ (Δ8Hd) However, [Δ8Hd−chi--- [SH]! ! As before, its sign is then, and the optimal compressor rotation speed at this time is determined by the following formula.

In other words, the correction amount ΔHz of the rotational speed is, however, the ΔH work is as before, and using formulas (1) to (5), the microcomputer calculates the following:
Arithmetic processing is performed, and each element is feedback-controlled.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

First, the cooling operation operates as follows. The refrigerant gas leaving the compressor 1 passes through the four-way valve 2 as shown by the dotted line, is condensed and liquefied in the outdoor heat exchanger 8, and is slightly reduced in pressure by the expansion valve 4 (v4). Then, the pressure is further reduced through the cabin retubes 58 to 5C to form an intermediate pressure. The refrigerant evaporates at the saturation temperature with respect to this intermediate pressure.For example, in the indoor heat exchanger 6a with a temperature of 9 0□, a cooling capacity commensurate with this temperature difference between the air side and the refrigerant side is generated. The pressure on the refrigerant side of the indoor heat exchanger 6a is controlled by the expansion valve 7a, and the degree of opening (as a result, the amount of heat exchanged) is adjusted so that the set room temperature is achieved. Similarly, the room temperature θ of other indoor heat exchangers 6bS6C
2. The opening degree of the expansion valves 7b and 7c is controlled so that #3 becomes a predetermined value (depending on the deviation). After the refrigerant is vaporized to a certain extent, it joins together, passes through the four-way valve 2, enters the accumulator 8, and is sucked into the compressor 1. This suction refrigerant is superheated on the discharge side, that is, from the temperature Td detected by the temperature sensor 12 and the refrigerant saturation temperature conversion jiTc (that is, condensation temperature) from the pressure of the pressure sensor 11, 8Hd-Td-T
c is calculated inside the microcomputer, and the expansion valve 4 (v4) is controlled so that this value becomes a predetermined value.

Next, in the heating cycle, the refrigerant gas discharged from the compressor 1 passes through the four-way valve 2 as shown by the solid line, goes to the branch point, and after branching, is depressurized by the f# tension valve 7a * 7be 7C. (
(forming intermediate pressure) indoor heat exchanger 6a t 6b I
Enter 6C. Here, heat exchange with the room air takes place at a cold S saturation temperature corresponding to the intermediate pressure. For example, when the room temperature θ becomes higher than the set value, g5! ni valve 7a
is controlled in the closing direction, the internal pressure (intermediate pressure) of the heat exchanger 6a moves in the downward direction, the refrigerant temperature decreases, and the amount of heat released to the air (remari heating capacity) decreases, making it impossible to raise the room temperature any further. It acts like there is no such thing. Thus, the expansion valve 7as? bs?
'by q! r Each room is maintained at a separate desired temperature by controlling the capacity of the indoor unit. The condensed liquid refrigerant joins together in the cavity 5a @ 5b 15C after being slightly depressurized.

The combined refrigerant is depressurized by the expansion valve 4 (V4) (as described later, the discharge side super heat is set to a predetermined value),
It is evaporated in the outdoor heat exchanger 8. Part 7) dks four-way valve 2,
It passes through the emleter 8 and is sucked into the compressor 1. As in the case of air conditioning, the discharge gas of the tftta machine is superheated (
The expansion valve 4 (V4) is controlled using the temperature Td of the temperature sensor 12 and the saturated source KiA calculation Tc of the pressure of the pressure sensor 11 so that Td Ip C) becomes a predetermined value.

For example, if expansion valves 7a and 7b remain constant, but only 7c closes a little (that is, when the heating capacity is reduced), the expansion valve 4 will close slightly in an attempt to maintain the discharge side heat. It will open.

Furthermore, a solenoid valve 9 and a capillary lO line are provided as devices for dealing with a transient abnormal rise in high pressure or an abnormal drop in low pressure. By opening this solenoid valve 9, abnormal pressure as described above can be prevented.

Next, the concept of the inventive punching device will be explained with reference to FIG.

That is, the temperature of each room is determined by the temperature sensor as #2.0.
3 is imported into the microcomputer. In addition, the discharge temperature Td of the compressor and its pressure (output of the pressure sensor 11 in Fig. 1) are taken into the microcomputer, and the five calculation processes described in the "effects" section above are performed, resulting in % expansion. Each valve is controlled to its optimum opening degree. The temperature of each chamber of the compressor is #, , a, ,
#, and its setting value (0□)! JET, [θ2)if
I (θ3) is processed by a microcomputer by a linear combination of the deviation with 1, and is passed through the inverter → compressor to ensure that there is no excess or deficiency.
Controlled to the optimum rotation speed.

81st Ad cold 7M, expansion valve Vl, l, V8 (4
1 This is a diagram showing how the refrigeration cycle reacts when 17a to 7c) are slightly opened as shown in figure (a) or closed as shown in figure Φ). be.

That is, as shown in figure (a), when the valve opens slightly, this means an increase in Δθ, which means a rise in room temperature), and an increase in the rotation speed of the compressor (this means that the compressor suction pressure Ps decreases). ), an increase in the amount of refrigerant distributed to the indoor unit, an increase in heat exchange capacity due to a decrease in the refrigerant temperature in the heat exchanger, an effect of pushing up the compressor suction pressure due to the opening of the valve, etc., work toward a favorable balance. It shows things.

Similarly, FIG. 4 shows expansion valves Vl, V2. The cycle response to V8 movement is shown for heating. That is, as shown in Figure (a), when the valve opens a little (that is, Δ0 decreases and the room temperature drops).

), compressor rotation speed increases (this acts to lower the compressor suction pressure), the refrigerant flow rate to the unit increases (by opening the valve), the compressor suction pressure tends to increase due to the valve opening (this It can be seen that the increase in heat exchange capacity due to the increase in the condensing temperature Tc (acting so as to cancel out the pressure drop effect due to the increase in the compressor rotation speed) and the increase in heat exchange capacity due to the increase in the condensing temperature Tc work together favorably and balance each other out.

When the valve closes slightly, it acts in the opposite direction and responds as shown in Figure 4 (b) of the fourth factor.

Next, the operation of the refrigeration cycle will be explained using a P-i diagram of the refrigerant. This is shown in Figure 5. (a) Figure shows cooling, (b) Figure shows heating. First, in cooling, the state of the refrigerant sucked into the compressor is C (point 8 in Figure 1), and the refrigerant is compressed and discharged. The refrigerant gas is in the state d.

The refrigerant cooled and liquefied in the outdoor heat exchanger (8 in Figure 41) enters the expansion valve V4 (7 in Figure 1) 4). The state at this time is e. Then, the state after branching and being depressurized at the middle Yabirari is 1asza+3a (room temperature θ□ in Fig. 1).
The state of the refrigerant at the heat exchanger inlet at the room temperature of 0□, the state of the refrigerant at the heat exchanger inlet at the room temperature of 03), and the state after evaporation in each indoor heat exchanger are as follows: lb,
2b and 8b. The pressure of these refrigerants is further reduced by expansion valves, and the point at which they meet is f. (In Figure 1, V
l-V8 left confluence). On the way, it is warmed by heat leakage and returns to the %C point.

Now, the heating cycle will be explained using the P-i diagram of the Φ) diagram as follows. That is, the compressed refrigerant is discharged from the state C of the refrigerant sucked into the compressor, and the state at this time is D. This goes to point F with fA loss on the way (
In FIG. 1, the state of the inlet of the expansion valves 7a+7b+7c),
After branching, the point where a slight decompression was performed in each # P.S.
2 people, 8A (in Figure 1, heat exchanger 31&
The state of the refrigerant at the entrance to the heat exchanger, the state of the refrigerant at the entrance to the heat exchanger, the room temperature 0. The states of the refrigerant cooled and liquefied in each indoor heat exchanger are 1B, 2B, and 811. These merge after the pressure is reduced due to a slight drop in the middle, resulting in the state at point E (in the diagram Cg1, the state is between the expansion valve 4 and the merging point). This is decompressed by the expansion valve, evaporated by the outdoor heat exchanger, reaches the zero point (8 in the $1 diagram), and is sucked into the compressor again. As can be seen from the above explanation, on the P-i diagram, each heat exchanger 1a-elb, 2a→"
The vertical levels of l b , 3 a - e3 b are controlled. Similarly, in heating, IA → IB t 2A-2
The vertical levels of B, aA-eaB are controlled.

The present invention is characterized in that the indoor heat exchanger is sandwiched between a constant throttle device (here, a capillary) and an electronic expansion valve, and the expansion valve is arranged on the downstream side during cooling and on the upstream side during heating. . This configuration is also applicable to a multi-refrigeration tickle that can be cooled and heated simultaneously. An example of this is shown in figure s6.

An example of the sixth factor is a case where two rooms are cooled and one room is heated.

The gas refrigerant discharged from the compressor 1 passes through the four-way valve 2, is appropriately reduced in pressure by the expansion valve 6, and is condensed in the indoor heat exchanger 65. The saturation pressure at this time is the same as the room temperature of 0. Before reaching the set value, the expansion valve 6 is adjusted in accordance with the deviation and is optimally controlled. After becoming a liquid refrigerant, the pressure is reduced in the capillary 4 and evaporated in the outdoor heat exchanger 8. The gas refrigerant passes through the four-way valve 2 and goes to the Akie emulator 17.

Heating is performed as described above.

On the other hand, the discharged gas passes through the four-way valve 7 to the outdoor heat exchanger 8.
There are also some that are reduced in size. The liquid refrigerant passes through the capillary 9, is depressurized, is evaporated in the indoor heat exchanger 10, and is evaporated in the electronic expansion valve 1.
1, the pressure is further reduced. At this time, the indoor heat exchanger internal pressure is
The amount of heat exchanged with the indoor air is determined according to the saturation temperature so that the set room temperature is achieved. The evaporated gas refrigerant is removed from the four-way valve 7.
After that, A:? Go to Yumureta 17.

The cooling action is performed in the same way in the line from the outdoor heat exchanger 618 to the indoor heat exchanger 615.

This embodiment can also be applied to a multi-type refrigerator, and the first factor embodiment is used for the refrigeration cycle. A major feature of this cycle is that each compartment can be used as either a freezer or a refrigerator, and the internal temperature can be set freely.

〔Effect of the invention〕

According to the present invention, the temperature of each room is arbitrarily and individually adjusted to a desired value automatically, and the rotational speed of the compressor is also controlled to a value commensurate with the total load.

Further, the super heat on the suction side or the discharge side of the compressor can also be adjusted to a predetermined value. In this way, not only is comfort improved, but there is no need for construction restrictions, and a multi-air conditioning system with low equipment costs, reliability, and high comfort can be provided.

[Brief explanation of drawings]

FIG. 1 is a refrigeration cycle diagram according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram of a control device that controls the cycle shown in FIG. Figure 3 shows the expansion valve during cooling (Vl, VB, v8 in Figure 1)
(2)
The figure shows the case when the expansion valve is open, and the Φ) figure shows the case when the expansion valve is closed. Figure 4 shows the expansion valve during heating (Vl, VB, 'l in Figure 1)
(a) is a diagram showing the movement of the cycle when the
The figure shows the case when the expansion valve is open, and the figure Φ) shows the case when #PS is closed. FIG. 5 is a P-i diagram of the refrigeration cycle, where (a) shows the cooling cycle and (b) shows the heating cycle. FIG. 6 shows another embodiment, and is a diagram of a multi-refrigeration cycle capable of simultaneous cooling and heating. 0□... Room temperature θ of indoor unit 1,... Room temperature 0 of indoor unit 2,... Room temperature π of 8 indoor units... Discharge gas temperature Tc of pressure am... Relative to the discharge pressure of the compressor Refrigerant saturation temperature 7a
~'7c #+fhRF, 廿(Vt, Vz, Vi) wealth 2nd 4th concave

Claims (1)

[Claims] In a multi-type air conditioner in which a plurality of indoor heat exchangers are installed in parallel to one rotational speed controlled compressor, electronic expansion is provided in the liquid line side piping of the outdoor heat exchanger. Install the valve. A capillary tube is installed in series between the electronic expansion valve and the plurality of indoor heat exchangers for each indoor heat exchanger. The refrigerant piping branches between the above-mentioned cabillary tube and the above-mentioned electronic expansion valve, and lines for each indoor heat exchanger are formed in parallel. Electronic expansion valves are installed in series on the gas line side piping of each indoor heat exchanger. Each indoor heat exchanger line branches between the indoor heat exchange electronic expansion valve and the four-way valve. The opening degrees of the indoor heat exchange expansion valves are independently feedback-controlled depending on the deviation between the room temperature and its desired value. The degree of opening of the outdoor heat exchange expansion valve is controlled based on the degree of superheating of the gas refrigerant on the discharge side or suction side of the compressor and the deviation between its expected value. The rotation speed of the compressor is controlled using a linear combination value of the deviation between the room temperature and the desired room temperature for each room. A multi-refrigeration cycle characterized by: