JPS6096866A - Multiple type air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a multi-type air conditioner that combines one outdoor unit and a plurality of indoor units.

[Technical background of the invention and its problems]

In conventional multi-type air conditioners, the number, capacity, etc. of indoor units that can be combined with an outdoor unit are determined in advance. If more than the specified number of indoor units are combined, or if indoor units of a type other than the specified type are combined, the indoor unit may not be able to perform to its specified capacity, or the L-dynamic compressor may be overloaded. Problems occur.It is a huge burden for manufacturers to prepare a wide variety of indoor units that can be used in combination, and it is almost impossible to actually remove them.For these reasons, indoor units Currently, because there are only a few types of products, it is not possible to fully satisfy the diverse needs of users.

In addition, with conventional multi-type air conditioners, the capacity of each indoor unit cannot be controlled individually according to the cooling load within each unit, so there is a large difference between the indoor cooling load and cooling capacity, and the room temperature In some cases, it takes too long to reach the set temperature.

[Purpose of Departure J]

This invention was made in consideration of the above circumstances, and regardless of whether or not the indoor unit is equipped with a refrigerant decompression device, the number and capacity of the guide unit 7) and the fl+l
To provide a multi-type air conditioner in which an indoor unit can be freely selected and combined with an outdoor unit without being subject to JPJi, and each indoor unit can control its capacity according to its load.

[Summary of the invention]

In this invention, when the indoor load changes, the suction side pressure of the electric compressor changes, and when the cooling load of the indoor unit changes, the temperature of the refrigerant returned from the indoor unit changes. The refrigerant temperature at the outlet of the bypass capillary tube provided between the high-pressure 111 tl refrigerant passage and the low-pressure side refrigerant passage is always constant, and is constructed as follows.

In other words, in response to changes in the indoor load, the power frequency to the electric compressor is controlled via the inverter based on commands from the compressor control unit in response to changes in the suction side pressure of the electric compressor detected by the pressure sensor. By adjusting the rotation speed ↓ to control the capacity of the dynamic compressor. In addition, in response to changes in the cooling load of the indoor unit, the branch pipes of the outdoor unit are designed to maintain the temperature difference between the outlet refrigerant temperature of the bypass capillary tube and the return refrigerant temperature from each guide unit at a predetermined value. The refrigerant flow rate adjustment valve is opened and closed by a flow rate adjustment valve control unit that adjusts the opening degree of the refrigerant flow rate adjustment valve, thereby supplying the optimal amount of refrigerant to the cooling load in each room.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. 1 in Figure 1 is the outdoor unit, and this extraneous unit 1
For example, three indoor units 2a, 2b
and 2C are combined. And each indoor unit) 2a.

2b and 2C are equipped with pressure reducing devices, 9a, Jb and 3C, and evaporators 4a, 4b and 4C, respectively. In addition, the electric compressor 5 in the outdoor unit 1 is powered by a main power source 6.
In-house with compressor control unit 2 for
They are connected via a computer 8. A pressure sensor 9 is provided electrically connected to the compressor control unit 7 to detect the suction side pressure of the electric compressor TA 5. A condenser 10 is provided downstream of the electric compressor 5, and is cooled by an outdoor blower 11).

A bypass pipe 12 is provided in front of the condenser 10 as a /4 inosine circuit. Then, the downstream stage of the condenser 10 and the Tsukuino! A condensing pressure W,!8I regulating valve 13 is provided at the confluence point with the spy 7''12.The condensing pressure AI'l,!8I regulating valve 13 is provided at the downstream side of the valve 13 via a liquid tank 14 to the valley chamber unit. Corresponding-
Branches 15a to 15C on the C outdoor unit 1 side are provided, and these branch pipes have refrigerant flow rate adjustment valves 16h to 16h, respectively.
16c, the opening degree of which can be adjusted in accordance with a command from a flow rate adjustment valve control unit 17 provided in the guide unit 1. The refrigerant flow rate adjustment valves 16a to 16c are connected to the indoor units 2a to 2C.
Even if any of the
When the room thermostat is off, one of the corresponding refrigerant flow rate adjustment valves 16a to 16c is fully closed. The flow rate adjustment valve control unit 17 controls the high pressure side and low pressure side of the refrigeration cycle. Suru no noi/? Scapillary tube 18
In order to control the temperature difference between the outlet refrigerant temperature and the return refrigerant temperature from each indoor unit 2a to 2C within a predetermined range, the opening degrees of the refrigerant flow rate adjustment valves 16h to 16c are adjusted. A temperature sensor 19 is provided on the outlet side of the bypass capillary tube 18, and temperature sensors 21a to 21a are provided to the branch pipes 20a to 20c of the return refrigerant pipes of the indoor units 2a to 2C on the outdoor unit 1 side. The second temperature sensors 19 and 21a to 21c are electrically connected to the second flow rate adjustment valve control unit 17, respectively, and the flow rate adjustment valve control unit 17 is connected to the refrigerant flow rate adjustment valves 16a to 21c.
16c.

“Niki Paino! An accumulator 22 is provided downstream of the confluence of the cavity 2 retup 18 and the low-pressure side refrigerant pipe.

Next, the operation of this invention constructed as in Section 2 will be explained. When the electric compressor 5 is kept at a constant rotation speed and a predetermined number of indoor units are in the middle of cooling operation, if the indoor (11!l) load changes, the number of operating indoor units increases or decreases, or the indoor cooling When the load changes, the pressure Ps on the suction side of the electric compression 85 changes significantly.

When the number of compressor cycles is constant and the number of domestic units 2 in operation increases or the indoor cooling load increases, P8 increases, and in the opposite case, P8 decreases. In this invention, the pressure sensor 9 detects the pressure Ps on the suction side of the electric compressor 5, and when ps increases, the compressor rotational speed is increased, and when P8 falls, the compressor rotational speed is decreased, so that ps is always maintained. Maintain within a certain range. That is, as shown in FIG. 2, the optimum compressor rotational speed R is always maintained according to the number of indoor operating units N and the cooling load t. However, even if the compressor rotational speed is set to the maximum rotational speed, if the pressure exceeds a certain range of ps, maintain a high rotational speed like the N line.

Next, the condenser 10 is provided with a bypass pipe 12 as a bypass circuit, and a condensation pressure NM % valve 13 is provided at the junction of the downstream side of the condenser 10 and this bypass pipe 12. The discharge gas flow flowing into the condenser 10 and the discharge gas flow passing through the bypass pipe 12 and passing through the condenser 1o are adjusted, as shown in FIG.
Even when the outside air temperature T is low, the condensing pressure Pc is always maintained at the set pressure value. However, if the amount of heat of condensation increases significantly or if the outside air temperature is extremely high, it will start to increase after a certain point.

``Okay, each room 1'' Units 2a to 2c are installed and the indoor cooling 1σ load changes.For example, assuming that the pressure 1ll-1 bale suction pressure Ps1Jc and the compression pressure pc are constant, the indoor cooling load is changed. When this becomes large, the raw refrigerant from the indoor unit is mixed with moss liquid of a gas refrigerant with a small degree of superheating, resulting in saturated gas cooling.

In other words, the change in indoor cooling shell, Rj is due to the saturation of the return refrigerant.
It appears as a change in superheat jjyΔTsh with respect to temperature.

The refrigerant at the exit of the bypass ghee/pavilari tube 18 is before it merges with the refrigerant in the main circuit, and there is almost no exchange of heat with the outside, so the temperature wave is almost saturated71'
1□ (can be considered as degrees. Therefore, each cold inner unit) 2 Return from a to 2c') Difference between the temperature of the cold a and the refrigerant temperature at the exit of the pipe scabilari noob 18 , Zunawa'shi, temperature sensors 21a and 19.2
1b and 19. Each detection of 21c and 19/Jii [difference ΔT
a, ΔTb, ΔTc are the respective indoor units) 2a to 2
The degree of superheat of the refrigerant returned from c.

In addition, as shown in FIG. 1, the refrigerant pressure is reduced by the refrigerant flow rate
4 Regulating valves 16a to 16a and pressure reducing device 3a in the indoor unit
~3C.

In the present invention, when the degree of superheating ΔTsh increases independently in the circuit of each indoor unit, the opening degree of the refrigerant flow rate regulating valves 16a to 16c is decreased, that is, the resistance is increased, and the refrigerant is circulated to the indoor units 2a to 2C. By increasing or decreasing the amount, the degree of superheat is maintained within a certain suitable range. That is, refrigerant can be supplied to each indoor unit at an optimal flow rate commensurate with the load.

Further, in the above embodiment, the indoor units 2a to 2C
are each equipped with a pressure reducing device 3a to 3C, but since the refrigerant flow rate regulating valves 16h to 16c have a pressure reducing function, an indoor unit without a pressure reducing device can also be used in combination with the outdoor unit 1 of the present invention. effective.

Further, in the above embodiment, the indoor units 28 to 2C
If any of the above is stopped or in operation but the thermostat is off, the refrigerant flow rate adjustment valves 16a-
16c is fully closed, but as shown in FIG. 4, a solenoid valve 2 is installed at any location in the refrigerant branch circuit of each indoor unit 2th to 2C, for example, upstream of the evaporator 4a.
3, the solenoid valves 23 are opened when each straw unit (2a to 2C) is in operation, and the solenoid valves 23 are opened when the room thermostat is off even though the units are stopped or in operation. may be closed.

Furthermore, in the above-mentioned embodiment, the confluence point with the main circuit on the outlet side of the pi/scanillary tube 18 was placed on the upstream side of the accumulator 22, but it is not limited to this position, and may be anywhere as long as it is on the low pressure side. . Furthermore, the inlet side may be arbitrarily selected as long as it is within the main circuit portion through which the high-pressure liquid refrigerant flows. As an example, the one shown in FIG. 1 is provided with a bypass valve 12 as a bypass circuit in the condenser 10, and a condensation pressure regulating valve 13 at the confluence of the discharge side of the condenser 10 and the bypass pipe 120. Although the bypass circuit 12 and the condensing pressure regulating valve 13 are removed from the one shown in FIG. 5, the same effect as in the first embodiment can be obtained.

In this case, as shown in FIG. 4, each of the indoor units 28 to 2C is
Regardless of whether or not a refrigerant pressure reducing device is installed in any indoor unit in the refrigerant branch circuit, the capacity of the indoor unit,
Since it can be freely combined with outdoor units, regardless of the number of units or the form of floor-mounted or ceiling-mounted units, it is not only possible to satisfy the diverse needs of users, but also to be able to independently operate each indoor unit. It becomes possible to control the capacity according to the cooling load. In addition, since the capacity of the electric compressor is controlled to the optimum state according to the load, the energy saving effect is significant. In addition, with conventional systems, if there is a difference in the length or inner diameter of the connecting piping between each indoor unit' and outdoor unit, there will be a difference in piping resistance, resulting in a large imbalance in the amount of refrigerant circulating through each indoor unit. In the case of this invention, there are almost no restrictions on indoor unit installation due to the length, inner diameter, etc. of the connection pipe, and the indoor unit can be installed freely to a certain extent. The installation has a great practical effect in that the location can be selected.

[Brief explanation of the drawing]

FIG. 1 is a refrigeration cycle diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing the total indoor load of the operating number N of indoor units and the cooling load t, and the suction side pressure p of the electric compressor.
3 is a graph showing the relationship between condensing heat iQ or outside air temperature T and condensing pressure pc, and FIG. 4 is a graph showing a modification of the present invention. FIG. 5 is a refrigeration cycle diagram showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Outdoor unit, 2a, 2b, 2c... Indoor unit, 5... Electric compressor, 7... Compressor control unit, 8... Inverter, 9... Pressure sensor, 10. ... Condenser, 15a, 15b, 15c...
・Outdoor branch pipe, 16a 116br 16c・
...Refrigerant flow rate adjustment valve, 17...Flow rate adjustment valve control unit.

Claims (1)

[Claims] In a multi-type air conditioner in which multiple indoor units are connected to one outdoor unit, a pressure sensor detects the suction side pressure of the electric compressor and controls the suction side pressure of the electric compressor. An electric compressor capacity control device comprising a compressor control unit and an inverter that controls the power frequency to the two electric compressors;
A refrigerant flow rate adjustment valve is provided in the outdoor branch pipe downstream of the condenser to correspond to each indoor unit, and the refrigerant flow rate adjustment valve is provided to control the degree of heating of the return refrigerant from each indoor unit within a predetermined range. 1. A multi-type air conditioner characterized by comprising a flow-view control valve control unit that adjusts the opening degree of the air conditioner.