JP2008039388A - Multi-type air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently ensure heating capability of an operating indoor unit in a multi-type air conditioner by appropriately controlling a stopped indoor heat exchanger and refrigerant collected in a liquid-side pipe even if the circumferential state of the stopped indoor unit is changed during heating operation. <P>SOLUTION: This air conditioner comprises a plurality of indoor units A and B connected in parallel to one outdoor unit C, temperature sensors 23a and 23b for detecting temperatures of liquid-side pipes 11a and 11b which are inlet side of electric expansion valves 7a and 7b in heating operation, and a control device. The control device includes a control means for correcting, based on the temperatures of the liquid-side pipes 11a and 11b on the stopped indoor unit side detected by the temperature sensors 23a and 23b in heating operation, the opening of the electric expansion valve 7a or 7b on the stopped indoor unit side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a multi-type air conditioner, and is suitable for a multi-type air conditioner configured by connecting a plurality of indoor units in parallel to one outdoor unit.

  In recent multi-type air conditioners, an electrically operated expansion valve associated with each indoor unit is provided only on the liquid side piping side, and an inexpensive refrigerant circuit in which the electromagnetic valve is eliminated from the gas side piping side. The number of air conditioning is increasing.

  An example of such a multi-type air conditioner (Prior Art 1) will be described with reference to FIG. In FIG. 4, the same reference numerals are assigned to the same or equivalent components in the present invention described later. In this example, two indoor units A and B are connected to one outdoor unit C. The two indoor units A and B are connected between the gas-side pipes 10a and 10b and the liquid-side pipes 11a and 11b, and include indoor heat exchangers 4a and 4b and indoor fans 5a and 5b, respectively. . On the other hand, the outdoor unit C is provided with a compressor 1, a four-way valve 2, an outdoor heat exchanger 8, and an outdoor fan 9. The liquid side pipes 11a and 11b in the outdoor unit C are provided with respective indoor units A and B. Electric expansion valves 7a and 7b corresponding to the above are provided. The refrigerant flows in the direction of the solid arrow during the heating operation.

  In this multi-type air conditioner, when heating the indoor units A and B simultaneously, the electric expansion valve 7a for the indoor unit A and the electric expansion valve 7b for the indoor unit B are individually provided according to the air conditioning load. By controlling and distributing an appropriate amount of refrigerant to the heat exchangers 4a and 4b of the indoor unit A and the indoor unit B, the refrigerant circuit can be operated efficiently. When the heating operation on the indoor unit A side is continued and the indoor unit B side is stopped, the refrigerant passage to the indoor unit B side is closed by fully closing the electric expansion valve 7b for the indoor unit B. The indoor unit A and the outdoor unit C that are in the heating operation form a refrigerant circuit.

  However, since the refrigerant circuit does not include the refrigerant ingress prevention valves corresponding to the indoor units A and B in the gas side pipes 10a and 10b, the indoor unit B in which the high-pressure gas refrigerant is stopped during the heating operation. Enters the indoor heat exchanger 4b and condenses after radiating heat. For this reason, if the electric expansion valve 7b for the indoor unit B is fully closed for a long time, a large amount of refrigerant stays in the indoor heat exchanger 4b and the liquid side pipe 11b of the indoor unit B, and the refrigerant circuit There was a drawback that the heating capacity on the indoor unit A side was significantly reduced due to the lack of the total refrigerant circulation.

  Therefore, in the conventional multi-type air conditioner, there is one in which the electric expansion valve on the refrigerant circuit on the stop side is opened at a predetermined opening to prevent the stagnation by performing the control of circulating the refrigerant. . For example, in the one disclosed in Japanese Patent Laid-Open No. 8-159590 (prior art 2), when starting the heating operation, the electric expansion valve corresponding to the indoor unit on the stop side is opened at a predetermined opening degree, and then the operation is started. Corresponding to the opening of the electric expansion valve on the side, the opening of the electric expansion valve on the stop side is also changed to prevent the refrigerant from staying. In addition, the initial opening on the stop side can be corrected by the capacity class and piping length of the connected indoor unit, and the operator switches the setting and corrects it at the time of installation using the setting switch provided in the outdoor control device. It is like that.

However, in the multi-type air conditioner of Prior Art 2, there is no disclosure about control in consideration of the degree of supercooling of the refrigerant returned from the indoor unit on the stop side. For this reason, when the ambient state of the stopped indoor unit, for example, the ambient temperature changes, it cannot reliably cope with the change in the amount of refrigerant accumulated in the heat exchanger and the liquid side pipe of the stopped indoor unit. There's a problem.

  Moreover, in the multi-type air conditioner of the prior art 2, since the operator switches and corrects the setting with the setting switch provided in the outdoor control device at the time of installation, there is a possibility that an erroneous setting of correction may occur. There's a problem.

  The first object of the present invention is to appropriately control the refrigerant accumulated in the stop-side indoor heat exchanger and the liquid-side pipe even when the ambient state of the indoor unit stopped during the heating operation changes, An object of the present invention is to provide a multi-type air conditioner that can sufficiently secure the heating capacity of an indoor unit that is operating.

  The second object of the present invention is to control easily the refrigerant that accumulates in the indoor heat exchanger on the stop side and the liquid side piping even if the ambient state of the indoor unit that is stopped during the heating operation changes with simple control. Accordingly, an object of the present invention is to provide a multi-type air conditioner that can sufficiently ensure the heating capacity of an indoor unit that is in operation.

  The third object of the present invention is to appropriately control the refrigerant accumulated in the indoor heat exchanger on the stop side and the liquid side piping without any erroneous operation during the heating operation, thereby improving the heating capacity of the indoor unit being operated. The object is to provide a multi-type air conditioner that can be sufficiently secured.

  A first feature of the present invention for achieving the first object is that a plurality of indoor units each having an indoor heat exchanger, a switching valve for connecting the indoor units in parallel and switching between cooling and heating operations, and In a multi-type air conditioner comprising: an outdoor unit that includes an electric expansion valve that individually controls the refrigerant flow rate corresponding to the indoor unit; and a control device that controls the expansion valve. The controller includes a temperature sensor for detecting a liquid side pipe temperature on the inlet side, and the control device is configured to detect the indoor unit stop side based on a liquid side pipe temperature on the indoor unit stop side detected by the temperature sensor during heating operation. The control means for correcting the opening degree of the electric expansion valve is provided.

  The second feature of the present invention for achieving the second object described above is that a plurality of indoor units each having an indoor heat exchanger, a switching valve for connecting the indoor units in parallel and switching between cooling and heating operations, and In a multi-type air conditioner comprising: an outdoor unit that includes an electric expansion valve that individually controls the refrigerant flow rate corresponding to the indoor unit; and a control device that controls the expansion valve. A temperature sensor for detecting the temperature of the liquid side pipe on the inlet side is provided, and the control device detects the liquid side pipe temperature on the indoor unit operation side and the liquid side on the indoor unit stop side detected by the temperature sensor during heating operation. Control to correct the opening of the electric expansion valve on the indoor unit stop side based on the piping temperature so that the liquid side piping temperature on the indoor unit operation side and the liquid side piping temperature on the indoor unit stop side have a predetermined temperature difference There is a means.

  The second feature of the present invention for achieving the third object is that a plurality of indoor units each having an indoor heat exchanger, a switching valve for connecting the indoor units in parallel and switching between cooling and heating operations, and In the multi-type air conditioner, comprising: an outdoor unit that includes an electric expansion valve that individually controls the refrigerant flow rate corresponding to the indoor unit; and a control device that controls the expansion valve. The storage device stores a correction parameter such as a capacity class and a volume class of the indoor heat exchanger at the time of assembly, and the control device opens the opening of the electric expansion valve on the indoor unit stop side based on the correction parameter during heating operation. Is provided with a control means for correcting the above.

  ADVANTAGE OF THE INVENTION According to this invention, even if the surrounding state of the indoor unit stopped at the time of heating operation changes, the refrigerant | coolant collected in a stop side indoor heat exchanger and liquid side piping can be controlled appropriately, and operation is carried out by this A multi-type air conditioner that can sufficiently secure the heating capacity of the indoor unit is obtained.

  Further, according to the present invention, the refrigerant that accumulates in the stop-side indoor heat exchanger and the liquid-side pipe is appropriately controlled by simple control even when the ambient state of the indoor unit that is stopped during the heating operation changes. Thus, a multi-type air conditioner that can sufficiently secure the heating capacity of the indoor unit being operated can be obtained.

  Further, according to the present invention, it is possible to appropriately control the refrigerant accumulated in the stop side indoor heat exchanger and the liquid side pipe during the heating operation without erroneously setting the correction parameter at the time of installation. A multi-type air conditioner that can sufficiently secure the heating capacity of the indoor unit is obtained.

  Hereinafter, a multi-type air conditioner according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

  FIG. 1 is a refrigerant circuit configuration diagram of a multi-type air conditioner according to an embodiment of the present invention. The multi-type air conditioner of this embodiment is an example in which two indoor units A and B are connected to one outdoor unit C.

  In the refrigerant circuit, the two indoor units A and B include gas side pipe connection valves 3a and 3b provided in the gas side pipes 10a and 10b and liquid side pipe connection valves 6a provided in the liquid side pipes 11a and 11b, 6b is connected to the outdoor unit C. The gas side pipe connection valves 3a and 3b and the liquid side pipe connection valves 6a and 6b are manual valves that are opened and closed during installation or the like, and are normally used in a fully opened state after installation. Each indoor unit A, B is provided with indoor heat exchangers 4a, 4b, indoor fans 5a, 5b, and room temperature sensors 32a, 32b. In the indoor units A and B, the indoor heat exchangers 4a and 4b having the same or different volumes are selected according to the user's request and combined with the outdoor unit C. The indoor fans 5a and 5b ventilate the indoor air through the indoor heat exchangers 4a and 4b to exchange heat, and cool or heat the indoor air. The room temperature sensors 32a and 32b detect the temperature of indoor air, and specifically detect the air temperature on the suction side of the indoor heat exchangers 4a and 4b.

  On the other hand, the outdoor unit C is provided with a compressor 1, a four-way valve 2, an outdoor heat exchanger 8, and electric expansion valves 7a and 7b. The four-way valve 2 switches whether the refrigerant gas discharged from the compressor 1 is led to the outdoor heat exchanger 8 or the indoor units A and B, and switches between the cooling operation and the heating operation. The state of the four-way valve 2 in FIG. 1 is a state in which the heating operation is performed, and the refrigerant circulates in the refrigerant circuit as indicated by solid arrows. The electric expansion valves 7a and 7b are provided in the liquid side pipes 11a and 11b corresponding to the indoor units A and B, respectively. In this refrigerant circuit, the gas side pipe connection valve 3a, the indoor heat exchanger 4a, the liquid side pipe connection valve 6a and the electric expansion valve 7a are connected in series, and the gas side pipe connection valve 3b, the indoor heat exchanger 4b, The liquid side pipe connection valve 6b and the electric expansion valve 7b are connected in series, and both series refrigerant circuits are connected in parallel. In the outdoor unit C, an outdoor fan 9 is disposed so as to vent outdoor air to the outdoor heat exchanger 8. And in order to detect the main refrigerant temperature of a refrigerant circuit, the refrigerant | coolant discharge temperature sensor 22 is arrange | positioned at the discharge piping of the compressor vicinity, and between electric expansion valve 7a, 7b and liquid side piping connection valve 6a, 6b. The subcooled refrigerant temperature sensors 23a and 23b are arranged in the pipes 11a and 11b.

  FIG. 2 is a control block diagram of the multi-type air conditioner according to the embodiment of the present invention. In FIG. 2, 21 is an outdoor control device provided in the outdoor unit C, 31 a is an indoor control device of the indoor unit A, and 31 b is an indoor control device of the indoor unit B.

  The two indoor control devices 31a and 31b are connected to the outdoor control device 21 through data transmission lines 51a and 51b for transmitting and receiving control signals. The indoor control devices 31a and 31b and the outdoor control device 21 constitute a control device for a multi-type air conditioner. Each of the indoor control devices 31a and 31b includes room temperature sensors 32a and 32b for detecting the room temperature, and correction parameters such as the capacity class of the indoor units A and B and the volume class of the indoor heat exchangers 4a and 4b. , B are connected to the storage devices 33a, 33b stored at the time of assembly, and receive control signals from the remote controllers 41a, 41b. The room temperature sensors 32a, 32b, the storage devices 33a, 33b, and the remote control 41a, Data is input from 41b, and predetermined control is performed based on the data.

  On the other hand, the outdoor control device 21 includes a refrigerant discharge temperature sensor 22 for detecting the temperature of the refrigerant discharged from the compressor 1, supercooled refrigerant temperature sensors 23a and 23b for detecting the supercooled refrigerant temperature, the compressor 1, And the electric expansion valves 7a and 7b are connected. The outdoor unit control device 21 obtains data from these and the indoor control devices 31a and 31b and controls them. Specifically, the compressor rotational speed detection means, the compressor rotational speed control means, and the electric expansion Control means such as valve control means is provided, and the compressor 1 and the electric expansion valves 7a and 7b are controlled by the control means. The refrigerant discharge temperature sensor 22 is provided on the discharge pipe in the vicinity of the compressor 1, and the supercooled refrigerant temperature sensors 23a and 23b are provided between the electric expansion valves 7a and 7b and the liquid side pipe connection valves 6a and 6b. Installed on the liquid side pipes 11a and 11b.

  An outline of the operation when both the indoor unit A and the indoor unit B are heated in the multi-type air conditioner configured as described above will be described. When the heating operation is started by the operation of the remote controllers 41a and 41b, the indoor control devices 31a and 31b control the indoor fans 5a and 5b according to the set wind speed received from the remote controllers 41a and 41b, as well as the heating operation start command and the heating capacity. And the correction parameter are transmitted to the outdoor control device 21 through the data transmission lines 51a and 51b. The heating capacity is set by calculating the air conditioning load at that time based on the set temperature set by the remote controllers 41a and 41b and the room temperature detected by the room temperature sensors 32a and 32b. The correction parameters are acquired from the storage devices 33a and 33b when the indoor control devices 31a and 31b are turned on, and are always transmitted to the outdoor control device 21 regardless of whether the indoor units A and B are operated or stopped.

  When the outdoor control device 21 receives a heating operation start command from the indoor units A and B, the outdoor control device 21 switches the four-way valve 2 to the heating cycle side and drives the outdoor fan 9 at a predetermined rotational speed. In accordance with the correction parameter B, each electric expansion valve 7a, 7b is narrowed to a predetermined initial opening for operation. Further, based on the rotation speed command value of the compressor 1 received from the indoor units A and B, the compressor rotation speed required for the operation of the two units is obtained by calculation to drive the compressor 1. Thereafter, the outdoor control device 21 compares the actual rotation speed detected by the compressor rotation speed detection means (hereinafter referred to as the compressor actual rotation speed N (n)) with the compressor rotation speed target value obtained by the above calculation. High-precision compressor rotation speed control is performed.

  Due to the action of the outdoor control device 21, the refrigerant in the refrigerant circuit flows in the direction of the arrow shown in FIG. The refrigerant compressed by the compressor 1 passes through the four-way valve 2 as a high-temperature and high-pressure gas refrigerant, flows into the indoor heat exchangers 4a and 4b, and dissipates heat to the air sent by the indoor fans 5a and 5b. It becomes. Thereafter, the pressure is reduced by passing through each of the electric expansion valves 7 a and 7 b, the air is heated by the outdoor fan 9 in the outdoor heat exchanger 8, and returns to the compressor 1 via the four-way valve 2.

  Next, the control operation of the electric expansion valves 7a and 7b adjusting the refrigerant circulation amount and the refrigerant temperature in the refrigerant circuit will be described with reference to FIG. FIG. 3 is a flowchart showing the operation of the electric expansion valve control means provided in the outdoor control device.

  The electric expansion valve control means includes refrigerant discharge temperature correction control (S1), compressor rotation speed deviation correction control (S2), distribution control (S3), and open / close control (S4). Each electric expansion valve is based on the detected refrigerant discharge temperature Td, the actual compressor speed N (n) detected by the compressor speed detecting means, and the subcooled refrigerant temperature detected by the subcooled refrigerant temperature sensors 23a and 23b. The valve opening degree of 7a, 7b is controlled.

  First, in the refrigerant discharge temperature correction control (S1), the electric expansion valve 7a, so that the temperature of the refrigerant compressed and discharged by the compressor 1, that is, the refrigerant discharge temperature Td becomes a predetermined temperature corresponding to the compressor rotation speed, The calculation for correcting the opening degree of 7b is performed. For this calculation, fuzzy calculation for correcting the refrigerant discharge temperature is used. When the refrigerant discharge temperature Td and the actual compressor speed N (n) are substituted for this calculation, the correction opening degree ΔPtd of the electric expansion valves 7a and 7b is obtained. It can be obtained with a sign. Hereinafter, the calculation result is referred to as a refrigerant discharge temperature correction opening degree ΔPtd.

  Next, in the compressor rotation speed deviation correction control (S2), the corrected opening when the rotation speed of the compressor 1 fluctuates due to the load fluctuation of the refrigerant circuit is obtained. In this calculation, the difference ΔN (n) = N (n) −N (n−1) when the actual rotational speed of the compressor fluctuates from N (n−1) to N (n) and a predetermined constant compressor. The signed correction opening degree ΔPn is obtained by multiplying by the rotation speed fluctuation correction constant Knm. Hereinafter, the calculation result is referred to as a compressor rotation speed fluctuation correction opening degree ΔPn.

  Next, in distribution control (S3), the number of operating indoor units A and B is detected to determine whether they are operating in two units or one unit (S31). The calculation is performed separately. The calculation during the operation of the two units is performed as distribution control for supplying an appropriate refrigerant circulation amount to each of the indoor units A and B. That is, the processing during the operation of the two units is performed by correcting each of the electric expansion valves 7a and 7b so that the supercooling refrigerant temperature Tsca corresponding to the indoor unit A and the supercooling refrigerant temperature Tscb corresponding to the indoor unit B are the same. An opening is calculated, the current temperature difference Tsc = Tscb−Tsca is calculated (S32), and this temperature difference Tsc is substituted for fuzzy calculation for distribution control to obtain a corrected opening ΔPtsc with a sign. (S33). On the other hand, the calculation during the operation of one unit is based on the correction parameters such as the capacity classes of the indoor units A and B and the volume classes of the indoor heat exchangers 4a and 4b received from the indoor control devices 31a and 31b. The difference correction constant Ksc is calculated (S34), and the temperature difference Tsc obtained by adding the temperature difference correction constant Ksc to the difference between the supercooling refrigerant temperature Tsca corresponding to the indoor unit A and the supercooling refrigerant temperature Tscb corresponding to the indoor unit B is obtained. Calculation is made (S35), and the temperature difference Tsc is substituted for fuzzy calculation for distribution control to obtain the corrected opening ΔPtsc with a sign (S33). The result obtained here is hereinafter referred to as a supercooled refrigerant temperature correction opening degree ΔPtsc. As described above, since the supercooling refrigerant temperature Tsca corresponding to the indoor unit A and the supercooling refrigerant temperature Tscb corresponding to the indoor unit B are controlled to have a predetermined temperature difference, extremely simple control and can do.

  Finally, in the opening / closing control (S4), the above-described three corrected openings ΔPtd, ΔPn, ΔPtsc are totaled with respect to the current openings Pa (n-1), Pb (n-1) of the electric expansion valves 7a, 7b. The target openings Pa (n) and Pb (n) are obtained (S41), and the electric expansion valves 7a and 7b are controlled to be opened and closed so as to match the target openings Pa (n) and Pb (n). . As described above, the three correction openings ΔPtd, ΔPn, and ΔPtsc are set by combining the refrigerant discharge temperature correction control (S1), the compressor rotation speed deviation correction control (S2), and the distribution control (S3). It is possible to correct the opening degree of the electric expansion valves 7a and 7b, which is extremely appropriate, and to further improve the heating operation performance.

  The electric expansion valves 7a and 7b are controlled at predetermined intervals so that the refrigerant circulation amount and the refrigerant temperature in the refrigerant circuit are continuously maintained in an optimum state.

  Next, details of the single operation when the indoor unit A is operated and the indoor unit B is stopped in the heating operation will be described with reference to FIGS. 1 to 3.

  When the outdoor control device 21 confirms that only one of the indoor units A has started the heating operation by a heating operation start command on the data transmission lines 51a and 51b, for example, the outdoor control device 21 switches the four-way valve 2 to the heating cycle side, 9 is driven at a predetermined number of revolutions, and the electric expansion valve 7a of the indoor unit A is narrowed to a predetermined initial opening for operation, and the electric expansion valve 7b of the indoor unit B is narrowed to a predetermined initial opening for stopping. Further, the outdoor control device 21 drives the compressor 1 by obtaining the compressor rotational speed necessary for one unit operation based on the command rotational speed of the compressor 1 received from the indoor unit A. Thereafter, in order to prevent the refrigerant from staying in the stopped indoor unit B and to maintain the refrigerant circulation amount and the refrigerant temperature in the entire refrigerant circuit continuously in an optimal state, the electric expansion valve control means controls each electric motor. The expansion valves 7a and 7b are controlled to a predetermined opening degree.

  The opening / closing operation of the electric expansion valves 7a and 7b in the single operation will be specifically described. Each electric expansion valve opening is corrected by the electric expansion valve control means in the same manner as the two-unit operation. However, since it is necessary to calculate the correction opening in consideration of the air conditioning load of the operating indoor unit A and the amount of heat leakage of the stopped indoor unit B for the distribution control during the single unit operation, the two units are operated. The corrected opening cannot be obtained simply by the same calculation as the time. Therefore, the operating indoor unit A is operated based on the correction parameters stored in the storage devices 33a and 33b, that is, the correction parameters such as the capacity classes of the indoor units A and B and the volume classes of the indoor heat exchangers 4a and 4b. The air conditioning load and the amount of heat leakage of the stopped indoor unit B are determined, and distribution control is performed so that a predetermined temperature difference is generated between the supercooled refrigerant on the operation side and the stop side.

  In the distribution control in the single unit operation, correction parameters such as the capacity classes of the indoor units A and B and the volume classes of the indoor heat exchangers 4a and 4b received from the indoor control devices 31a and 31b in step S34 of FIG. First, a predetermined temperature difference correction constant Ksc is obtained by calculation. Next, in step S35 in FIG. 3, the temperature difference correction constant Ksc is added when the current temperature difference Tsc is calculated. The result is substituted for fuzzy calculation for distribution control, and the corrected opening degree ΔPtsc is obtained with a sign. In step S34, the temperature difference correction constant Ksc is obtained with a sign so that even if one of the indoor unit A and the indoor unit B is operated alone, the calculation of step S34 is performed without dividing the case of the indoor unit. The expression is made available.

  By controlling the electric expansion valves 7a and 7b at predetermined intervals, it is possible to prevent the refrigerant from staying in the stop-side indoor heat exchangers 4a and 4b and the liquid-side connection pipe in the single operation, The refrigerant circulation amount and the refrigerant temperature are continuously maintained in an optimum state.

  In the above-described embodiment, in the multi-type air conditioner configured by connecting a plurality of indoor units A and B to a single outdoor unit C, the heating operation including the stopped indoor unit A is included. When performing the operation, the electric expansion valves 7a and 7b are controlled so that a predetermined temperature difference is obtained by detecting the temperature of the subcooling refrigerant on the side of the operating indoor unit and the temperature of the subcooling refrigerant on the side of the stopped indoor unit. Thus, the refrigerant is prevented from staying in the stop-side indoor heat exchanger 4b and the liquid-side connection pipe 11b without being affected by air-conditioning load factors such as room temperature and outside air temperature, and the heating capacity of the indoor unit A in operation is reduced. It can be pulled out sufficiently.

  Even if a plurality of different types of indoor units A and B are connected to one outdoor unit C, the correction parameters such as the capacity class of the indoor units A and B and the volume class of the indoor heat exchangers 4a and 4b are controlled. By adding to the above control as an element, the control can be optimized.

  Furthermore, storage devices 33a and 33b are provided for storing correction parameters such as capacity classes of the indoor units A and B and volume classes of the indoor heat exchangers 4a and 4b. When the air conditioner is assembled, the storage devices 33a and 33b are provided. By storing the correction parameters and acquiring the correction parameters by the control means that automatically acquires the correction parameters from the storage devices 33a and 33b when controlling the electric expansion valves 7a and 7b, erroneous setting due to human error is prevented. Thus, the above control can be reliably operated.

  As described above, the embodiment of the present invention in the multi-type air conditioner in which two indoor units A and B are connected to one outdoor unit C has been described. However, three or more indoor units are used as one outdoor unit. The present invention can also be applied to connected multi-type air conditioners. In the case of a multi-type air conditioner in which three or more indoor units are connected to one outdoor unit, when all indoor units are heated, the maximum temperature is determined from the supercooling refrigerant temperature sensor corresponding to each indoor unit. By detecting the minimum temperature and controlling the motorized expansion valve so that this temperature difference is the same temperature, the refrigerant circulation amount and the refrigerant temperature in the refrigerant circuit in each indoor unit are continuously maintained in the optimum state. Is possible.

  In addition, when performing heating operation including a stopped indoor unit, an average value of the operation side supercooling refrigerant temperature and an average value of the stop side supercooling refrigerant temperature are obtained, and this temperature difference is a predetermined temperature difference. By controlling so as to become stable, the refrigerant is prevented from staying in the stopped indoor heat exchanger and the liquid side connection pipe, and the refrigerant circulation amount and the refrigerant temperature in the refrigerant circuit are continuously adjusted appropriately. It is possible to maintain the state.

It is a refrigerant circuit block diagram of the multi type air conditioner in one Embodiment of this invention. It is a control block diagram of the air conditioner. It is a flowchart figure which shows the control action of the electric expansion valve in the air conditioner. It is a refrigerant circuit block diagram of the conventional multi type air conditioner.

Explanation of symbols

  A ... Indoor unit, B ... Indoor unit, C ... Outdoor unit, 1 ... Compressor, 2 ... Four-way valve, 3a, 3b ... Gas side pipe connection valve, 4a, 4b ... Indoor heat exchanger, 5a, 5b ... Indoor fan 6a, 6b ... Liquid side pipe connection valve, 7a, 7b ... Electric expansion valve, 8 ... Outdoor heat exchanger, 9 ... Outdoor fan, 10a, 10b ... Gas side pipe, 11a, 11b ... Liquid side pipe, 21 ... Outdoor Control device, 22 ... refrigerant discharge temperature sensor, 23a, 23b ... supercooled refrigerant temperature sensor, 31a, 31b ... indoor control device, 32a, 32b ... room temperature sensor, 33a, 33b ... storage device, 41a, 41b ... remote control, 51a, 51b: Data transmission line.

Claims (9)

A plurality of indoor units each having an indoor heat exchanger, the indoor unit connected in parallel, a switching valve for switching between cooling and heating operation, and an electric expansion valve for individually controlling the refrigerant flow rate corresponding to the indoor unit In a multi-type air conditioner comprising an outdoor unit and a control device that controls the expansion valve,
A temperature sensor for detecting the temperature of the liquid side pipe that becomes the inlet side of the electric expansion valve during heating operation,
The control device includes control means for correcting the opening of the electric expansion valve on the indoor unit stop side based on the liquid side piping temperature on the indoor unit stop side detected by the temperature sensor during heating operation. Multi-type air conditioner. A plurality of indoor units each having an indoor heat exchanger, the indoor unit connected in parallel, a switching valve for switching between cooling and heating operation, and an electric expansion valve for individually controlling the refrigerant flow rate corresponding to the indoor unit In a multi-type air conditioner comprising an outdoor unit and a control device that controls the expansion valve,
A temperature sensor for detecting the temperature of the liquid side pipe that becomes the inlet side of the electric expansion valve during heating operation,
The controller controls the liquid side piping temperature on the indoor unit operation side and the indoor unit based on the liquid side piping temperature on the indoor unit operation side and the liquid side piping temperature on the indoor unit stop side detected by the temperature sensor during heating operation. A multi-type air conditioner comprising control means for correcting the opening of an electric expansion valve on the indoor unit stop side so that the liquid side pipe temperature on the stop side has a predetermined temperature difference.   3. The control device according to claim 2, wherein the controller is configured to control the liquid side pipe temperature on the indoor unit operation side and the liquid side on the indoor unit stop side based on correction parameters such as the capacity class of the indoor unit and the volume class of the indoor heat exchanger during heating operation. A multi-type air conditioner characterized by being a control means for correcting a predetermined temperature difference from the pipe temperature.   3. The predetermined temperature between the liquid side piping temperature on the indoor unit operation side and the liquid side piping temperature on the indoor unit stop side by combining the refrigerant discharge temperature correction of the compressor and the rotation speed fluctuation correction of the compressor in claim 2. A multi-type air conditioner characterized by being a control means for correcting the difference. A plurality of indoor units each having an indoor heat exchanger, the indoor unit connected in parallel, a switching valve for switching between cooling and heating operation, and an electric expansion valve for individually controlling the refrigerant flow rate corresponding to the indoor unit In a multi-type air conditioner comprising an outdoor unit and a control device that controls the expansion valve,
During the heating operation, the control device, based on the subcooling refrigerant temperature on the indoor unit operation side and the subcooling refrigerant temperature on the indoor unit stop side, and the supercooling refrigerant on the indoor unit stop side A multi-type air conditioner comprising control means so that a temperature difference is a predetermined temperature.   6. The control means according to claim 5, wherein the average value of the subcooling refrigerant temperature on the indoor unit operation side and the average value of the subcooling refrigerant temperature on the indoor unit stop side are obtained and controlled so that the temperature difference between the two becomes a predetermined temperature difference. A multi-type air conditioner characterized by A plurality of indoor units each having an indoor heat exchanger, the indoor unit connected in parallel, a switching valve for switching between cooling and heating operation, and an electric expansion valve for individually controlling the refrigerant flow rate corresponding to the indoor unit In a multi-type air conditioner comprising an outdoor unit and a control device that controls the expansion valve,
Each of the indoor units includes a storage device that stores correction parameters such as the capacity class of the indoor unit and the volume class of the indoor heat exchanger at the time of assembly.
The said control apparatus is provided with the control means which correct | amends the opening degree of the said electric expansion valve by the side of an indoor unit based on a correction parameter at the time of heating operation, The multi-type air conditioner characterized by the above-mentioned.   8. The liquid side piping temperature on the indoor unit stop side detected by the temperature sensor for detecting the liquid side piping temperature on the inlet side of the electric expansion valve during heating operation and detecting the temperature sensor during heating operation according to claim 7. The multi-type air conditioner is provided with a control means for correcting the opening of the electric expansion valve on the indoor unit stop side based on the control unit. A plurality of indoor units each having an indoor heat exchanger and an indoor fan, each of which can be individually operated and stopped, and the indoor unit connected in parallel via a pipe connection valve, and a switching valve for switching between cooling and heating operations and the indoor In a multi-type air conditioner comprising an outdoor unit equipped with an electric expansion valve that individually controls the refrigerant flow rate corresponding to the machine, and a control device that controls the expansion valve,
A temperature sensor for detecting a refrigerant temperature between the electric expansion valve and the liquid side pipe connection valve;
During the heating operation, the control device determines whether the liquid side pipe temperature on the indoor unit operation side and the liquid side pipe temperature on the indoor unit stop side are based on correction parameters such as the capacity class of the indoor unit and the volume class of the indoor heat exchanger. Corrects a predetermined temperature difference, and based on the liquid side piping temperature on the indoor unit operation side and the liquid side piping temperature on the indoor unit stop side detected by the temperature sensor, the liquid side piping temperature on the indoor unit operation side and the indoor unit stop A multi-type air conditioner comprising control means for correcting the opening of the electric expansion valve on the indoor unit stop side so that the liquid side pipe temperature on the side has a predetermined temperature difference.

Images