JP7316759B2 - Air conditioner and air conditioning system - Google Patents

Description

TECHNICAL FIELD The present invention relates to an air conditioner and an air conditioning system that include a plurality of user-side heat exchangers and a plurality of fans.

Patent Literature 1 describes an air conditioning system. This air conditioning system has a diffusion outlet device for blowing conditioned air into the indoor space in a diffused state, and a local outlet device for intensively blowing the conditioned air to the indoor space in a predetermined direction. there is In this air conditioning system, when conditioned air is blown out from the blower outlet device for local blowing, the air volume from the blower outlet device for diffusion blowing is suppressed. As a result, it is possible to suppress the energy consumption required for supplying the conditioned air while ensuring the comfort of the user.

JP 2016-35371 A

However, in the air conditioning system of Patent Literature 1, no consideration is given to the operating states of the elemental devices of the refrigeration cycle that serve as heat sources for the conditioned air. Therefore, even if the energy required to supply the conditioned air is reduced, the energy required to operate the refrigeration cycle may increase. Therefore, in the air conditioning system of Patent Literature 1, there is a problem that the energy saving of the entire air conditioning system including the heat source of the conditioned air may not be realized.

The present invention has been made to solve the problems described above, and an object of the present invention is to provide an air conditioner and an air conditioning system that can improve energy saving.

An air conditioner according to the present invention includes a compressor, a heat source side heat exchanger functioning as a condenser, a plurality of pressure reducing devices, and a plurality of user side heat exchangers functioning as an evaporator, and a refrigerant that circulates the refrigerant. a circuit, a plurality of air blowers that supply air to the plurality of utilization side heat exchangers, respectively, and a plurality of utilization units that respectively accommodate the plurality of utilization side heat exchangers and the plurality of air blowers; a first usage-side heat exchanger that is one of the plurality of usage-side heat exchangers; a first fan that is one of the plurality of fans; and when a value obtained by subtracting a set temperature, which is a target value of the temperature, from the temperature of the air-conditioned space of each of the plurality of usage units is defined as the temperature difference between each of the plurality of usage units, the The first blower is driven at a first rotation speed when the temperature difference of the first usage unit is a first value, and the second blower is driven at a first rotation speed when the temperature difference of the first usage unit is smaller than the first value. When the value of maintained within a range of higher than 0° C. and 5° C. or less both when the temperature difference between the usage units is the first value and when the temperature difference between the first usage units is the second value; The frequency of the compressor is the temperature difference of only the usage unit with the largest temperature difference among the plurality of usage units, or the temperature difference of only the usage unit having the usage side heat exchanger with the largest capacity among the plurality of usage units. It is controlled based on the temperature difference.
An air conditioning system according to the present invention includes a plurality of air conditioners that share and air-conditions the same space, and a system controller that controls the plurality of air conditioners, and each of the plurality of air conditioners: A refrigerant circuit including a compressor, a heat source side heat exchanger functioning as a condenser, a plurality of decompression devices, and a plurality of user side heat exchangers functioning as evaporators, circulating a refrigerant, and the plurality of user side heat a plurality of air blowers that respectively supply air to heat exchangers; and a plurality of utilization units each housing the plurality of utilization side heat exchangers and the plurality of air blowers, wherein a first heat exchanger is one of the plurality of utilization units. One usage unit accommodates a first usage-side heat exchanger that is one of the plurality of usage-side heat exchangers and a first fan that is one of the plurality of fans, and When a value obtained by subtracting a set temperature, which is a target value of the temperature, from the temperature of the air-conditioned space of each of the usage units is defined as the temperature difference between the plurality of usage units, the first blower is used for the first usage. When the temperature difference of the unit is a first value, it is driven at a first rotational speed, and when the temperature difference of the first utilization unit is a second value smaller than the first value, the The degree of superheat of the refrigerant flowing out from each of the plurality of usage-side heat exchangers in the refrigerant circuit is such that the temperature difference of the first usage unit is the first and when the temperature difference of the first usage unit is the second value, the air conditioner is maintained in a range of higher than 0°C and 5°C or lower, and the system controller is, during the period from when the plurality of air conditioners start up until the temperature difference between all of the plurality of usage units of the plurality of air conditioners becomes equal to or less than the threshold temperature difference, It is configured to prohibit a decrease in the number of revolutions.

ADVANTAGE OF THE INVENTION According to this invention, the rotation speed of a 1st air blower can be reduced based on the temperature difference of a 1st utilization unit, maintaining a refrigerant circuit in the state with high operating efficiency. As a result, the energy required for operating the first blower can be reduced while suppressing the energy required for operating the refrigerant circuit. Therefore, according to the present invention, the energy saving performance of the air conditioner can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic plan view which shows the structure and installation mode of the air conditioning system 100 which concerns on Embodiment 1 of this invention. 3 is a schematic side view showing the configuration and installation mode of usage unit 302A1 and usage unit 302B1 of air-conditioning system 100 according to Embodiment 1 of the present invention. FIG. Fig. 2 is a refrigerant circuit diagram showing the configuration of the air conditioner 300A of the air conditioning system 100 according to Embodiment 1 of the present invention. 1 is a block diagram showing the configuration of a heat source-side control device 101A, a user-side control device 121A1, and a user-side control device 121A2 of the air-conditioning system 100 according to Embodiment 1 of the present invention; FIG. 4 is a flowchart showing an example of the control flow of the air conditioner 300A executed by the heat source side control device 101A of the air conditioning system 100 according to Embodiment 1 of the present invention. 4 is a graph showing an example of the relationship between the temperature difference of the user units and the rotation speed setting level of the user-side fan in the air-conditioning system 100 according to Embodiment 1 of the present invention. 4 is a graph showing temporal changes in operating conditions in a general air conditioner as a comparative example of Embodiment 1 of the present invention. 4 is a graph showing temporal changes in the operating state of the air conditioner 300A of the air conditioning system 100 according to Embodiment 1 of the present invention. 4 is a flow chart showing an example of the control flow of a usage unit 302A1 executed by a usage-side control device 121A1 of the air-conditioning system 100 according to Embodiment 1 of the present invention. 4 is a flowchart showing an example of the flow of control executed by system controller 110 of air-conditioning system 100 according to Embodiment 1 of the present invention. FIG. 10 is a flow chart showing an example of the control flow of the air conditioner 300A executed by the heat source side control device 101A of the air conditioning system 100 according to Embodiment 2 of the present invention. FIG.

Embodiment 1.
An air conditioner and an air conditioning system according to Embodiment 1 of the present invention will be described. FIG. 1 is a schematic plan view showing the configuration and installation mode of an air conditioning system 100 according to this embodiment. FIG. 2 is a schematic side view showing the configuration and installation mode of usage unit 302A1 and usage unit 302B1 of air conditioning system 100 according to the present embodiment. In FIGS. 1 and 2, the flow of air is indicated by solid line arrows or dashed line arrows. In the present embodiment, as the air conditioning system 100, an air conditioning system that is installed in a building such as an office building and conditions the air in a large indoor space 500 is exemplified.

First, the indoor space 500 of the building in which the air conditioning system 100 is installed will be described. The indoor space 500 has an office 501 and a corridor 502 provided on one side of the office 501 . The office 501 is the main air-conditioned space of the air conditioning system 100 as a whole. The office 501 is a room where a plurality of workers do desk work. Although illustration is omitted, a plurality of sets of desks, chairs, and the like are arranged in the office 501 . A window 503 is provided on the other side of the office 501 .

A plurality of pillars 504A1 and 504A2, which are part of the building, are provided at predetermined intervals along the window 503 on the perimeter side of the office 501, that is, on the window 503 side of the office 501. FIG. Although only two pillars 504A1 and 504A2 are shown in FIG. 1, three or more pillars may be provided along the window 503. FIG. A plurality of pillars 504B1 and 504B2, which are part of the building, are provided along the corridor 502 at predetermined intervals on the interior side of the office 501, that is, on the corridor 502 side of the office 501. FIG. Although only two pillars 504B1, 504B2 are shown in FIG. 1, three or more pillars may be provided along the corridor 502. FIG.

The air conditioning system 100 includes an air conditioner 300A that mainly shares the perimeter-side area of the office 501 and air-conditions it, an air conditioner 300B that mainly shares the interior-side area of the office 501, and air-conditions the area. have. In the following description, the air conditioner 300A and the air conditioner 300B may be referred to as system A and system B, respectively. Each of the air conditioners 300A and 300B has a refrigerant circuit in which a vapor compression refrigeration cycle is executed. Both the air conditioner 300A and the air conditioner 300B are configured to be able to perform at least cooling operation.

The air conditioner 300A has a heat source unit 301A, a usage unit 302A1 and a usage unit 302A2. Each of the usage unit 302A1 and the usage unit 302A2 is connected to the heat source unit 301A via a connection pipe 6A and a connection pipe 10A that form part of the refrigerant circuit of the air conditioner 300A (see FIG. 3). The connecting pipe 6A is a liquid pipe through which liquid refrigerant mainly flows, and the connecting pipe 10A is a gas pipe through which gas refrigerant mainly flows. The heat source unit 301A is arranged outdoors such as on the roof of a building. The usage units 302A1 and 302A2 are arranged inside the pillars 504A1 and 504A2 on the perimeter side of the office 501, respectively. The air conditioner 300A may have three or more usage units. For example, when three or more perimeter-side pillars are provided along the window 503, three or more usage units may be arranged inside these pillars.

The usage unit 302A1 has an air outlet 307A1 and an air inlet 308A1 both facing the office 501 . The outlet 307A1 and the inlet 308A1 are provided on the surface of the column 504A1 facing the column 504B1. The air outlet 307A1 is arranged at a position lower than the ceiling 501a of the office 501 . The air outlet 307A1 is desirably arranged at a height position such that the height from the floor surface 501b of the office 501 is equal to or less than the height of the person in the office 501. A person's height is identified by, for example, the average height in the country where the air conditioning system 100 is installed. The correct height position of the outlet 307A1 is specified, for example, by the height position of the upper end of the outlet 307A1. The suction port 308A1 is arranged at a position lower than the outlet 307A1 and higher than the floor surface 501b. In addition, the usage unit 302A1 includes a usage side heat exchanger 8A1 that forms part of the refrigerant circuit of the air conditioner 300A, and a usage side fan 9A1 that blows air to the usage side heat exchanger 8A1. .

The air outlet 307A1 is provided with a vertical wind direction plate (not shown) for adjusting the direction of the blown air in the vertical direction. The vertical wind direction plate is driven by a wind direction plate drive mechanism 309A1, which will be described later. In FIG. 2, the solid line arrows indicate the air flow when the direction of the blown air is adjusted diagonally downward, and the broken line arrows indicate the air flow when the direction of the blown air is adjusted diagonally upward. showing.

The usage unit 302A1 also has a human sensor 310A1 that detects whether or not a person exists in the air-conditioned space of the usage unit 302A1. The human sensor 310A1 is installed, for example, near the outlet 307A1. An infrared sensor, for example, is used as the human sensor 310A1.

The usage unit 302A2 has the same configuration as the usage unit 302A1. In other words, the usage unit 302A2 has an air outlet 307A2 and an air inlet (not shown) both facing the office 501 . The blowout port 307A2 and the suction port are provided on the surface of the column 504A2 facing the column 504B2. The blowout port 307A2 and the suction port are provided at the same height positions as the blowout port 307A1 and the suction port 308A1, respectively. The air outlet 307A2 is provided with a vertical wind direction plate (not shown). The vertical wind direction plate is driven by a wind direction plate drive mechanism 309A2, which will be described later. The usage unit 302A2 includes a usage side heat exchanger 8A2 that forms part of the refrigerant circuit of the air conditioner 300A, a usage side blower 9A2 that blows air to the usage side heat exchanger 8A2, and the usage unit 302A2. and a human sensor 310A2 that detects whether or not a person exists in the air-conditioned space.

The air conditioner 300B has the same configuration as the air conditioner 300A. That is, the air conditioner 300B has a heat source unit 301B, a usage unit 302B1 and a usage unit 302B2. Each of the usage unit 302B1 and the usage unit 302B2 is connected to the heat source unit 301B via a connection pipe 6B and a connection pipe 10B that form part of the refrigerant circuit of the air conditioner 300B. The heat source unit 301B is arranged outdoors such as on the roof of a building. The usage units 302B1 and 302B2 are arranged inside the pillars 504B1 and 504B2 on the interior side of the office 501, respectively. The air conditioner 300B may have three or more usage units. For example, when three or more interior-side pillars are provided along the corridor 502, three or more usage units may be arranged inside these pillars.

The usage unit 302B1 has an air outlet 307B1 and an air inlet 308B1 both facing the office 501 . The blowout port 307B1 and the suction port 308B1 are provided on the surface of the column 504B1 facing the column 504A1. The blowout port 307B1 and the suction port 308B1 are provided at the same height positions as the blowout port 307A1 and the suction port 308A1, respectively. The air outlet 307B1 is provided with a vertical wind direction plate driven by a wind direction plate driving mechanism. The usage unit 302B1 includes a usage-side heat exchanger 8B1 that constitutes a part of the refrigerant circuit of the air conditioner 300B, a usage-side fan 9B1 that blows air to the usage-side heat exchanger 8B1, and the usage unit 302B1. and a human sensor 310B1 that detects whether or not a person exists in the air-conditioned space.

The usage unit 302B2 has an air outlet 307B2 facing the office 501 and an air inlet (not shown). The blowout port 307B2 and the suction port are provided on the surface of the column 504B2 facing the column 504A2. The blowout port 307B2 and the suction port are provided at the same height positions as the blowout port 307A1 and the suction port 308A1, respectively. The air outlet 307B2 is provided with a vertical wind direction plate driven by a wind direction plate driving mechanism. The usage unit 302B2 includes a usage-side heat exchanger 8B2 that forms part of the refrigerant circuit of the air conditioner 300B, a usage-side blower 9B2 that blows air to the usage-side heat exchanger 8B2, and the usage unit 302B2. and a human sensor 310B2 that detects whether or not a person exists in the air-conditioned space.

The operation of each usage unit will be described using the usage unit 302A1 as an example. When the usage side blower 9A1 operates in the usage unit 302A1, the air on the perimeter side of the office 501 is sucked into the housing of the usage unit 302A1 through the suction port 308A1. The air sucked into the usage unit 302A1 passes through the usage side heat exchanger 8A1, becomes conditioned air, and is blown out to the perimeter side of the office 501 through the outlet 307A1.

During the cooling operation, the density of the cold air cooled by the user-side heat exchanger 8A1 is higher than the density of the indoor air, so the cold air blown into the office 501 from the air outlet 307A1 is below the height at which it was blown. gradually flows down to As a result, during the cooling operation, stratified air conditioning can be performed with the lower space of the office 501 as the main space to be air-conditioned. Here, the lower space is a space in the height range from the height of the floor surface 501b to the height of the outlet 307A1. In particular, when the suction port 308A1 is provided at a position lower than the air outlet 307A1, air circulation is established between the lower space and the air passage in the usage unit 302A1, so stratified air conditioning can be performed more efficiently. . When stratified air conditioning is performed, the cooling load of the space above the lower space, such as near the ceiling 501a, is not processed, so the load of the air conditioning system 100 during cooling operation can be reduced. Therefore, according to the present embodiment, power consumption of the air conditioning apparatus 300A and the air conditioning system 100 including the air conditioning apparatus 300A can be reduced as compared with an air conditioning system in which the outlet is provided on the ceiling.

Here, in the present embodiment, outlet 307A1 is provided on the surface of pillar 504A1, but outlet 307A1 may be provided on the surface of the wall facing office 501. FIG. The same applies to other outlets 307A2, 307B1, and 307B2. In addition, although usage unit 302A1 of the present embodiment is a built-in type that is incorporated into a building such as pillar 504A1, usage unit 302A1 may be of a floor-mounted type having an air outlet in the housing. When the floor-standing type usage unit is installed on the floor surface 501b, the air outlet is located at a height lower than the ceiling 501a, so stratified air conditioning similar to that described above can be performed. The same applies to other usage units 302A2, 302B1, and 302B2.

FIG. 3 is a refrigerant circuit diagram showing the configuration of the air conditioner 300A of the air conditioning system 100 according to the present embodiment. Since the air conditioner 300B has the same configuration as the air conditioner 300A, illustration of the air conditioner 300B is omitted in FIG. As shown in FIG. 3, the refrigerant circuit 20 of the air conditioner 300A includes a compressor 1, a four-way valve 2, a heat source side heat exchanger 3, user side pressure reducing devices 7A1 and 7A2, user side heat exchangers 8A1 and 8A2, and an accumulator. 11 are annularly connected via refrigerant pipes. A set of the user side pressure reducing device 7A1 and the user side heat exchanger 8A1 and a set of the user side pressure reducing device 7A2 and the user side heat exchanger 8A2 are connected in parallel with each other in the refrigerant circuit 20 .

The compressor 1 is a fluid machine that draws in low-pressure gas refrigerant, compresses it, and discharges it as high-pressure gas refrigerant. As the compressor 1, a frequency-adjustable inverter-driven compressor is used. The four-way valve 2 is a channel switching device that switches the flow direction of the refrigerant between cooling operation and heating operation.

The heat source side heat exchanger 3 is a heat exchanger that functions as a condenser during cooling operation and as an evaporator during heating operation. In the heat source side heat exchanger 3 , heat exchange is performed between the refrigerant flowing inside and the outdoor air blown by the heat source side blower 4 .

The user-side decompression devices 7A1 and 7A2 are valves that decompress the refrigerant by throttle expansion. An electronic expansion valve whose opening degree can be adjusted is used as the user-side decompression devices 7A1 and 7A2. The degree of opening of each of the user-side decompression devices 7A1 and 7A2 is controlled so that the degree of superheating or supercooling of the refrigerant approaches a target value. During cooling operation, for example, the degree of opening of the user-side pressure reducing device 7A1 is controlled so that the degree of superheat of the refrigerant at the outlet of the user-side heat exchanger 8A1 approaches a target value, and the degree of opening of the user-side pressure reducing device 7A2 is controlled so that The degree of superheat of the refrigerant at the outlet of the device 8A2 is controlled so as to approach the target value.

The utilization side heat exchangers 8A1 and 8A2 are heat exchangers that function as evaporators during cooling operation and as condensers during heating operation. In the user-side heat exchanger 8A1, heat exchange is performed between the refrigerant flowing inside and the indoor air blown by the user-side fan 9A1. In the user-side heat exchanger 8A2, heat exchange is performed between the refrigerant flowing inside and the room air blown by the user-side fan 9A2. Each of the user-side fans 9A1 and 9A2 is driven at a rotational speed setting level, which will be described later. The accumulator 11 is a container that separates liquid refrigerant and gas refrigerant and stores excess refrigerant.

The air conditioner 300A also has a bypass passage 14 that diverts part of the refrigerant flowing between the heat source side heat exchanger 3 and the user side pressure reducing devices 7A1 and 7A2 and returns it to the accumulator 11 . The bypass flow path 14 is provided with a bypass pressure reducing device 12 that reduces the pressure of the refrigerant branched to the bypass flow path 14 . As the bypass decompression device 12, an electronic expansion valve whose degree of opening can be adjusted is used. Furthermore, the air conditioner 300A cools the refrigerant flowing between the heat source side heat exchanger 3 and the user side decompression devices 7A1 and 7A2 by heat exchange with the refrigerant decompressed by the bypass decompression device 12 for subcooling heat exchange. It has a vessel 13 .

The compressor 1, the four-way valve 2, the heat source side heat exchanger 3, the subcooling heat exchanger 13, the accumulator 11, the bypass pressure reducing device 12 and the heat source side blower 4 are accommodated in the heat source unit 301A. The user-side decompression device 7A1, the user-side heat exchanger 8A1, and the user-side blower 9A1 are housed in the user unit 302A1. The user-side decompression device 7A2, the user-side heat exchanger 8A2, and the user-side blower 9A2 are housed in the user unit 302A2. The heat source unit 301A and the utilization unit 302A1 and the utilization unit 302A2 are connected via the connection pipe 6A and the connection pipe 10A, respectively.

The refrigerant circuit 20 of the air conditioner 300A is provided with a plurality of temperature sensors for detecting refrigerant temperature and a plurality of pressure sensors for detecting refrigerant pressure. The plurality of temperature sensors include a temperature sensor 201 provided on the discharge side of the compressor 1, a temperature sensor 204 provided on the liquid side of the heat source side heat exchanger 3, and a high pressure side outlet of the supercooling heat exchanger 13. , temperature sensors 206A1 and 206A2 provided on the liquid sides of the utilization side heat exchangers 8A1 and 8A2, and gas sides of the utilization side heat exchangers 8A1 and 8A2. Temperature sensors 208A1 and 208A2, a temperature sensor 210 provided at the low pressure side inlet of the subcooling heat exchanger 13, and a temperature sensor 211 provided at the low pressure side outlet of the subcooling heat exchanger 13 are included. . As the plurality of pressure sensors, a pressure sensor 221 provided on the discharge side of the compressor 1 to detect the high pressure side pressure of the refrigerant circuit 20 and a pressure sensor 221 provided on the upstream side of the accumulator 11 to detect the low pressure side pressure of the refrigerant circuit 20 A pressure sensor 222 is included.

A temperature sensor 203 that detects the temperature of outdoor air before passing through the heat source side heat exchanger 3 is provided in the heat source unit 301A. The usage unit 302A1 is provided with a temperature sensor 207A1 that detects the temperature of the room air sucked into the usage unit 302A1 as the temperature of the air-conditioned space of the usage unit 302A1. The usage unit 302A2 is provided with a temperature sensor 207A2 that detects the temperature of the room air sucked into the usage unit 302A2 as the temperature of the air-conditioned space of the usage unit 302A2.

The refrigerant used in refrigerant circuit 20 is not limited to a specific refrigerant. As the refrigerant, for example, HFC (Hydro Fluoro Carbon) refrigerant such as R410A or R32, HCFC (Hydro Chloro Fluoro Carbon) refrigerant, or natural refrigerant such as hydrocarbon or carbon dioxide can be used.

The heat source unit 301A has a heat source side control device 101A that controls the operation of the heat source unit 301A. The usage unit 302A1 has a usage side control device 121A1 that controls the operation of the usage unit 302A1. The usage unit 302A2 has a usage side control device 121A2 that controls the operation of the usage unit 302A2.

The air conditioning system 100 has a system controller 110 . The system controller 110 has an arithmetic section, a control section, a storage section, and a communication section. The system controller 110 communicates with the heat source side control device 101A and the user side control devices 121A1 and 121A2 of the air conditioner 300A, and also communicates with the heat source side control device and the user side control device of the air conditioner 300B (both not shown). are configured to communicate with each other. In addition, the system controller 110 is configured to control the air conditioners 300A and 300B as a higher-order control device than the heat source side control device and the user side control device of each of the air conditioners 300A and 300B.

FIG. 4 is a block diagram showing configurations of the heat source side control device 101A, the usage side control device 121A1, and the usage side control device 121A2 of the air conditioning system 100 according to the present embodiment. Each of the heat source side control device 101A, usage side control device 121A1, and usage side control device 121A2 has a microcomputer equipped with a CPU, ROM, RAM, I/O port, and the like. The heat source side control device and the usage side control device of the air conditioner 300B have the same configuration as the heat source side control device 101A and the usage side control devices 121A1 and 121A2.

As shown in FIG. 4, the heat source side control device 101A has a measurement section 102A, a calculation section 103A, a control section 104A, a storage section 105A and a communication section 106A. Measurement unit 102A acquires temperature information of each part based on detection signals output from temperature sensors 201, 203, 204, 205, 210, and 211, respectively. In addition, the measurement unit 102A acquires pressure information of each part based on detection signals output from the pressure sensors 221 and 222, respectively. 103 A of calculation parts calculate various control parameters based on the information of the temperature and the pressure which were acquired by 102 A of measurement parts. The control unit 104A controls each component of the heat source unit 301A including the compressor 1, the four-way valve 2, the bypass decompression device 12, and the heat source side blower 4 based on the control parameters calculated by the calculation unit 103A. The storage unit 105A stores information such as set values necessary for calculation of control parameters and control target values of devices. The communication unit 106A transmits and receives information to and from the user-side control devices 121A1 and 121A2 and the system controller 110 by wired communication or wireless communication via a communication line.

The user-side control device 121A1 has a measurement section 122A1, a calculation section 123A1, a control section 124A1, a storage section 125A1, and a communication section 126A1. Measurement unit 122A1 acquires temperature information of each part based on detection signals output from temperature sensors 206A1, 207A1, and 208A1. Measurement unit 122A1 also acquires information as to whether or not a person exists in the air-conditioned space of usage unit 302A1 based on the detection signal output from human sensor 310A1. The computing unit 123A1 computes various control parameters based on the information acquired by the measuring unit 122A1. The control section 124A1 controls each device of the usage unit 302A1 including the usage side decompression device 7A1, the usage side blower 9A1, and the wind direction plate drive mechanism 309A1 based on the control parameters calculated by the calculation section 123A1. The storage unit 125A1 stores information such as set values necessary for calculation of control parameters and control target values of devices. The communication unit 126A1 transmits and receives information to and from the heat source side control device 101A and the system controller 110 by wired communication or wireless communication via a communication line.

The user-side control device 121A2 has a measurement section 122A2, a calculation section 123A2, a control section 124A2, a storage section 125A2, and a communication section 126A2. The measurement unit 122A2, the calculation unit 123A2, the control unit 124A2, the storage unit 125A2, and the communication unit 126A2 are similar to the measurement unit 122A1, the calculation unit 123A1, the control unit 124A1, the storage unit 125A1, and the communication unit 126A1 of the user-side control device 121A1, respectively. have a function.

Next, the operation of the air conditioner 300A will be described by taking the cooling operation as an example. Each of the plurality of usage units 302A1 and 302A2 is provided with a remote control as an operation unit that receives operations by the user. When the cooling operation is selected with at least one of these remote controllers, the air conditioner 300A performs the cooling operation. When the cooling operation is performed, the four-way valve 2 is switched so that the discharge side of the compressor 1 is connected to the gas side of the heat source side heat exchanger 3 and the suction side of the compressor 1 is connected to the connecting pipe 10A. . In FIG. 3, the flow path of the four-way valve 2 during cooling operation is indicated by solid lines.

A high-temperature, high-pressure gas refrigerant discharged from the compressor 1 flows through the four-way valve 2 into the heat source side heat exchanger 3 . In the heat source side heat exchanger 3, heat is exchanged between the refrigerant and the outdoor air, and heat of condensation of the refrigerant is radiated to the outdoor air. As a result, the refrigerant that has flowed into the heat source side heat exchanger 3 is condensed into a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flowing out of the heat source side heat exchanger 3 is cooled by heat exchange with the low-pressure refrigerant in the supercooling heat exchanger 13 . The liquid refrigerant cooled by the supercooling heat exchanger 13 is divided into a flow path toward the connecting pipe 6A and the bypass flow path 14 . The liquid refrigerant diverted to the bypass flow path 14 is decompressed by the bypass decompression device 12 , heated by heat exchange with the high-pressure refrigerant in the subcooling heat exchanger 13 , and flows into the accumulator 11 . On the other hand, the liquid refrigerant diverted to the flow path toward the connection pipe 6A flows into the usage unit 302A1 or the usage unit 302A2 via the connection pipe 6A.

The liquid refrigerant that has flowed into the usage unit 302A1 is decompressed by the usage side decompression device 7A1 to become a low-pressure two-phase refrigerant, and flows into the usage side heat exchanger 8A1. In the use-side heat exchanger 8A1, heat is exchanged between the refrigerant and the indoor air, and the evaporation heat of the refrigerant is absorbed from the indoor air. As a result, the refrigerant that has flowed into the user-side heat exchanger 8A1 evaporates and becomes a low-pressure gas refrigerant. Also, the indoor air is cooled by the heat absorbing action of the refrigerant. The gas refrigerant that has flowed out of the usage-side heat exchanger 8A1 joins with the gas refrigerant that has flowed out of the usage-side heat exchanger 8A2, and flows into the heat source unit 301A via the connecting pipe 10A.

The gas refrigerant that has flowed into the heat source unit 301</b>A flows through the four-way valve 2 and joins the refrigerant that has flowed through the bypass flow path 14 to flow into the accumulator 11 . Gas refrigerant in the accumulator 11 is sucked into the compressor 1 . The gas refrigerant sucked into the compressor 1 is compressed into a high-temperature and high-pressure gas refrigerant. In cooling operation, the above cycle is continuously repeated.

The degree of opening of the usage-side decompression device 7A1 is controlled by the usage-side control device 121A1 so that the degree of superheat of the refrigerant at the outlet of the usage-side heat exchanger 8A1 approaches a target value. The degree of superheat of the refrigerant at the outlet of the utilization side heat exchanger 8A1 is calculated by subtracting the temperature detected by the temperature sensor 206A1 from the temperature detected by the temperature sensor 208A1. The degree of opening of the usage-side decompression device 7A2 is controlled by the usage-side control device 121A2 so that the degree of superheat of the refrigerant at the outlet of the usage-side heat exchanger 8A2 approaches the target value. The degree of superheat of the refrigerant at the outlet of the utilization side heat exchanger 8A2 is calculated by subtracting the temperature detected by the temperature sensor 206B1 from the temperature detected by the temperature sensor 208A2.

When the usage unit 302A1 is stopped by the remote controller of the usage unit 302A1, the usage side decompression device 7A1 is controlled to the fully closed opening degree. As a result, the refrigerant does not flow through the utilization side heat exchanger 8A1. Similarly, when the usage unit 302A2 is stopped by the remote control of the usage unit 302A2, the usage side decompression device 7A2 is controlled to the fully closed opening degree. As a result, the refrigerant does not flow through the utilization side heat exchanger 8A2.

The degree of opening of the bypass decompression device 12 is controlled by the heat source side control device 101A so that the degree of superheat of the refrigerant at the low pressure side outlet of the supercooling heat exchanger 13 approaches the target value. The degree of superheat of the refrigerant at the low pressure side outlet of the supercooling heat exchanger 13 is calculated by subtracting the temperature detected by the temperature sensor 210 from the temperature detected by the temperature sensor 211 .

The rotation speed of the heat source side blower 4 is controlled by the heat source side controller 101A so that the condensing temperature of the refrigerant approaches a target value (for example, 40° C.). The condensation temperature of the refrigerant is the saturation temperature of the pressure detected by the pressure sensor 221 .

Here, the value obtained by subtracting the set temperature, which is the target value of the temperature of the air-conditioned space, from the temperature of the air-conditioned space of the usage unit 302A1 (for example, the temperature detected by the temperature sensor 207A1) is the temperature difference of the usage unit 302A1. Define. Similarly, the value obtained by subtracting the set temperature, which is the target value of the temperature of the air-conditioned space, from the temperature of the air-conditioned space of the usage unit 302A2 (for example, the temperature detected by the temperature sensor 207A2) is the temperature difference of the usage unit 302A2. Define. The temperature difference between the usage units 302A1 and 302A2 is usually large during start-up operation immediately after the air conditioning apparatus 300A is started, and smaller during steady-state operation. Even when there are usage units other than the usage units 302A1 and 302A2, the temperature difference is defined for each usage unit.

One usage unit among the plurality of usage units 302A1 and 302A2 of the air conditioner 300A (that is, system A) is identified as the representative usage unit of the air conditioner 300A. As the representative usage unit of the air conditioner 300A, for example, the usage unit with the largest temperature difference is selected from among the usage units 302A1 and 302A2. On the other hand, when the temperature difference between the usage units 302A1 and 302A2 is small, the air conditioner 300A is in a stable operating state. In such a case, the usage unit having the usage-side heat exchanger with the largest capacity among the usage units 302A1 and 302A2 may be selected as the representative usage unit of the air conditioner 300A. For example, if the temperature difference of the usage unit 302A1 is 0.5°C and the temperature difference of the usage unit 302A2 is 0°C, the difference between the maximum temperature difference and the minimum temperature difference is 0.5°C. If the difference between the maximum temperature difference and the minimum temperature difference is, for example, less than 1° C., it is determined that the temperature difference between the usage units 302A1 and 302A2 is small.

The frequency of the compressor 1 is controlled by the heat source side control device 101A based on the temperature difference of the representative usage units of the air conditioner 300A. For example, the frequency of the compressor 1 is controlled so that the temperature difference of the representative usage unit of the air conditioner 300A approaches a target value (eg, 0° C.). By controlling the frequency of the compressor 1 based on the temperature difference of the representative usage unit of the air conditioner 300A, it is possible to suppress frequent fluctuations of the frequency of the compressor 1, so that the operating state of the air conditioner 300A can be stabilized. can be kept in

A method for controlling the compressor 1 of the air conditioner 300A will be specifically described. FIG. 5 is a flowchart showing an example of the control flow of the air conditioner 300A executed by the heat source side control device 101A of the air conditioning system 100 according to the present embodiment. Note that the control shown in FIG. 5 may be executed by either the user-side control device 121A1, the user-side control device 121A2, or the system controller 110. FIG. The control of the air conditioner 300B executed by the heat source side control device 101B or the like is the same as the control of the air conditioner 300A, so the explanation is omitted. In the following explanation, it is assumed that all the usage units are in cooling operation or stopped.

First, in the air conditioner 300A, the superheat degree target values of all the utilization-side heat exchangers 8A1 and 8A2 that are in operation are set to relatively low values higher than 0°C and 5°C or lower (for example, 2°C). (Step S1). If the superheat target value has already been set, the set superheat target value is maintained as it is, or the superheat target value is changed within a range from 0°C to 5°C. The degree of opening of the user-side depressurizing device 7A1 is controlled so that the degree of superheat of the user-side heat exchanger 8A1 approaches the superheat degree target value, and the degree of opening of the user-side depressurizing device 7A2 is controlled so that the degree of superheat of the user-side heat exchanger 8A2 superheats. degree target value. As a result, the degrees of superheat of the refrigerants flowing out of the use-side heat exchangers 8A1 and 8A2 are both maintained in the range of higher than 0° C. and 5° C. or lower. In general, the lower the degree of superheat of the utilization side heat exchanger, the more efficiently the refrigerant circuit 20 operates. Generally, low superheat means that the superheat is higher than 0°C and 5°C or lower.

Next, the temperature difference between all the usage units 302A1 and 302A2 in operation is calculated (step S2).

Next, one representative usage unit is identified from all usage units in operation (step S3). The representative utilization unit is selected based on the temperature difference of each of the plurality of utilization units or the capacity of each of the plurality of utilization side heat exchangers, as described above. For example, when three usage units 302A1, 302A2, and 302A3 are in operation, the set temperature of each usage unit is 26° C., and the intake air temperature of each usage unit is 26° C., 25.5° C., It shall be 26.5°C. At this time, the temperature differences among the usage units 302A1, 302A2, and 302A3 are 0.degree. C., -0.5.degree. C., and +0.5.degree. Therefore, the usage unit 302A3 with the maximum temperature difference of +0.5° C. is selected as the representative usage unit. Information on the specified representative usage unit and information on the temperature difference of the representative usage unit are stored in the storage unit 105A.

Next, the frequency of the compressor 1 is controlled based on the temperature difference of the representative unit (step S4).

The processing from the next step S5 to step S7 is sequentially executed for all the usage units in the operating state. That is, when n usage units 302Ai (i=1 to n) are operating in the air conditioner 300A, the processing from step S5 to step S7 is performed for each of the n usage units. .

In step S5, it is determined whether or not the usage unit is the representative usage unit. If the usage unit is the representative usage unit, the process proceeds to step S6, and if the usage unit is not the representative usage unit, the process proceeds to step S7.

In step S6, the rotation speed setting level of the user-side fan of the user unit is set to "strong". That is, the rotation speed setting level of the usage side fan of the representative usage unit is set to "high". The rotational speed setting level will be described later with reference to FIG.

In step S7, the rotation speed setting level of the user-side fan of the user unit is set based on the temperature difference of the user unit. That is, the setting level of the rotation speed of the usage-side fan of the usage unit other than the representative usage unit is set based on the temperature difference of the usage unit. The relationship between the temperature difference of the usage unit and the rotation speed setting level of the usage side fan will be described later with reference to FIG.

When the processes of steps S5 to S7 have been executed for all of the operating units, the process proceeds to step S8. In step S8, it is determined whether or not all the usage units of the air conditioner 300A have stopped. If all the usage units have stopped, the control shown in FIG. 5 is terminated, and if at least one usage unit is operating, the process returns to step S1.

FIG. 6 is a graph showing an example of the relationship between the temperature difference of the user units and the rotation speed setting level of the user-side fan in the air-conditioning system 100 according to the present embodiment. The horizontal axis of FIG. 6 represents the temperature difference (° C.) of the usage unit, and the vertical axis represents the rotation speed setting level of the usage side fan. The user-side fan of the operating user unit is controlled to one of four rotational speed setting levels: "low/stop", "low", "medium" and "high". The highest rpm setting level is "strong" and the lowest rpm setting level is "weak/stop".

As shown in FIG. 6, when the temperature difference between the usage units is +0.5° C. or more, the rotation speed setting level of the usage side fan is set to “strong”. That is, when the temperature difference between the usage units is +0.5° C. or more, the rotation speed setting level of the usage side fan is set to the same level as that of the usage side fan of the representative usage unit. When the rotational speed setting level is set to "strong", the user-side fan continuously operates at the rotational speed f3, which is the maximum rotational speed for control.

When the temperature difference between the usage units is 0° C. or more and less than +0.5° C., the rotation speed setting level of the usage side fan is set to “medium”. When the rotational speed setting level is set to "medium", the user-side fan continuously operates at the rotational speed f2 lower than the rotational speed f3. When the temperature difference between the usage units is -0.5°C or more and less than 0°C, the rotation speed setting level of the usage side fan is set to "weak". When the rotational speed setting level is set to "low", the user-side fan continuously operates at the rotational speed f1 lower than the rotational speed f2. The number of rotations f1 is the minimum number of rotations for control of the fan on the user side. When the temperature difference of the utilization unit is less than -0.5°C, the rotation speed setting level of the utilization side fan is set to "weak/stop". When the rotation speed setting level is set to "weak/stop", the user-side fan operates at the rotation speed f1 and stops when the rotation speed reaches the stop rotation speed f0 (for example, 0 rpm) at predetermined time intervals. alternately repeat.

When the user-side fan of a general user unit is set to the lowest rotational speed setting level of "weak", it continuously operates at the rotational speed f1, which is the lowest rotational speed for control. For this reason, in order to further reduce the air volume and suppress the heat exchange in the user-side heat exchanger, the rotation speed of the user-side fan had to be set to the stop rotation speed f0. However, when the rotation speed of the user-side blower reaches the stop rotation speed f0, the air in the air-conditioned space is no longer sucked into the usage unit, so the temperature sensor that detects the intake air temperature cannot detect the temperature of the air-conditioned space. put away.

On the other hand, in the present embodiment, "weak/stopped" is provided as a rotational speed setting level lower than "weak". When the rotational speed setting level is set to "low/stop", the user-side fan intermittently operates at the rotational speed f1. Therefore, the air in the air-conditioned space can be sucked into the usage unit while suppressing heat exchange in the usage-side heat exchanger. Therefore, the temperature sensor for detecting the intake air temperature can detect the temperature of the space to be air-conditioned, so that the temperature difference between the utilization units can be calculated with high accuracy.

FIG. 7 is a graph showing temporal changes in operating conditions in a general air conditioner as a comparative example of the present embodiment. (a) of FIG. 7 represents a temporal change in the total number of rotations [rpm] of a plurality of user-side fans. (b) represents the time change of the opening [pulse] (number of pulses) of one user-side decompression device. (c) represents the change over time in the degree of superheat [° C.] of the use-side heat exchanger provided downstream of the use-side decompression device. (d) represents the time change of the COP[-] of the refrigeration cycle of the air conditioner. In the initial state before time t1, the air conditioner is stopped, and the opening degree of the user-side decompression device is the fully closed opening degree.

As shown in FIG. 7, it is assumed that the operation of the air conditioner is started at time t1. The total number of rotations of the plurality of use-side fans is maintained at a constant value after time t1. The opening of the user-side decompression device is first controlled to a high opening (time t1), and then controlled to gradually decrease as the degree of superheat of the user-side heat exchanger rises (time t1 to t2 ~ t3). When the temperature difference of each of the plurality of usage units approaches the target value, the opening of the usage-side decompression device is reduced (time t3 to t4) in order to suppress the capacity of each usage unit, and then the opening is reduced. (after time t4). However, if the opening of the user-side decompression device is maintained at a low opening, the degree of superheat of the user-side heat exchanger is maintained at a high value, resulting in a decrease in the COP, which indicates the operating efficiency of the refrigeration cycle. Even if the rotation speed of each user-side blower is individually reduced, the COP of the refrigeration cycle will still decrease if the opening of the user-side decompression device is reduced. Therefore, in a typical air conditioner, the power consumption of the refrigeration cycle may increase.

FIG. 8 is a graph showing temporal changes in the operating state of air conditioner 300A of air conditioning system 100 according to the present embodiment. (a) of FIG. 8 represents a temporal change in the total number of rotations [rpm] of the plurality of user-side fans 9A1 and 9A2. (b) represents the time change of the opening [pulse] (number of pulses) of one user-side decompression device 7A1. (c) represents the change over time in the degree of superheat [° C.] of the user-side heat exchanger 8A1 provided downstream of the user-side decompression device 7A1. (d) represents the time change of the COP[-] of the refrigeration cycle of the air conditioner 300A. In the initial state before time t11, the air conditioner 300A is stopped, and the opening degree of the user-side decompression device 7A1 is the fully closed opening degree.

As shown in FIG. 8, it is assumed that the operation of the air conditioner 300A is started at time t11. The opening of the user-side decompression device 7A1 is first controlled to a high opening (time t11), and then controlled to gradually decrease as the degree of superheat of the user-side heat exchanger 8A1 increases (time t11). ~ t12). After the degree of superheat of the usage-side heat exchanger 8A1 reaches a target value (for example, 2° C.), the degree of opening of the usage-side decompression device 7A1 is maintained regardless of the temperature difference of the usage unit 302A1 (after time t12). . As a result, after time t12, the degree of superheat of the utilization side heat exchanger 8A1 is maintained near the target value regardless of the temperature difference of the utilization unit 302A1. In this embodiment, the rotation speeds of the usage side fans 9A1 and 9A2 are controlled based on the temperature difference between the usage units 302A1 and 302A2, respectively. Therefore, when the temperature difference between the usage units 302A1 and 302A2 approaches the respective target values (for example, 0° C.), the rotational speeds of the usage side fans 9A1 and 9A2 decrease (time t12 to t13). After that, when the temperature difference between the usage units 302A1 and 302A2 reaches the respective target values, the rotation speeds of the usage side fans 9A1 and 9A2 are maintained at a low rotation speed (time t13 to t14). For example, even if the user-side fan 9A2 stops at time t14, the rotational speed of the user-side fan 9A1 and the degree of opening of the user-side pressure reducing device 7A1 are maintained, so the degree of superheat of the user-side heat exchanger 8A1 is close to the target value. (after time t14). Therefore, according to the present embodiment, the degree of superheat of the utilization side heat exchanger 8A1 is maintained at a low value, so the COP of the refrigeration cycle of the air conditioner 300A can be maintained at a high value. Thereby, the power consumption of the refrigerating cycle of the air conditioner 300A can be reduced. Here, the power consumption of the refrigeration cycle of the air conditioner 300A is the power consumption of the compressor 1 .

In the present embodiment, while the degree of superheat of all the user-side heat exchangers of the air conditioner 300A is maintained at a low value (step S1 in FIG. 5), the rotation of the user-side fans of the user units other than the representative user unit The number can be lowered (steps S5-S7 in FIG. 5). Therefore, not only can the power consumption of the refrigerating cycle be reduced, but also the fan power of the user-side fan can be reduced, so that the energy saving performance of the air conditioner 300A can be greatly improved.

Furthermore, in this embodiment, the frequency of the compressor 1 is controlled based on the temperature difference of the representative usage unit (step S4 in FIG. 5). As a result, the frequency of the compressor 1 is kept low so as not to generate excess heat, so the power consumption of the refrigeration cycle of the air conditioner 300A can be further reduced.

Here, in air conditioning system 100 of the present embodiment, outlets 307A1, 307A2, 307B1, and 307B2 are arranged at positions lower than ceiling 501a. For this reason, compared with an air conditioning system in which the air outlet is installed on the ceiling, in the present embodiment, the conditioned air can be blown from a height position close to the height at which people are present. In an air-conditioning system in which the air outlet is installed on the ceiling, if the rotation speed of the user-side fan is reduced, it may be difficult to deliver the conditioned air to the height at which people are present. On the other hand, in the air-conditioning system 100 of the present embodiment, even if the air volume of the conditioned air is reduced by reducing the rotation speed of the user-side fan, the conditioned air can reach the height at which people are present. . Therefore, according to the present embodiment, it is possible not only to improve energy saving but also to maintain comfort.

FIG. 9 is a flow chart showing an example of the flow of control of usage unit 302A1 executed by usage-side control device 121A1 of air-conditioning system 100 according to the present embodiment. The control shown in FIG. 9 is executed for every usage unit. Therefore, the same control is executed in each of the plurality of user-side control devices of the user-side control device 121A2 and the air conditioner 300B. The control shown in FIG. 9 may be executed by either the heat source side control device 101A or the system controller 110. FIG.

In step S11 of FIG. 9, the user-side control device 121A1 determines whether or not a person exists in the air-conditioned space of the user unit 302A1 based on the output signal of the human sensor 310A1. When the presence of a person is detected by the human sensor 310A1, that is, when it is determined that a person exists in the air-conditioned space of the usage unit 302A1, the process proceeds to step S12. On the other hand, if the presence of a person is not detected by the human sensor 310A1, that is, if it is determined that no person exists in the air-conditioned space of the usage unit 302A1, the process proceeds to step S14.

In step S12, the user-side control device 121A1 controls the wind direction plate driving mechanism 309A1 so that the wind direction of the conditioned air blown out from the air outlet 307A1 is horizontal or obliquely upward. In the present embodiment, outlet 307A1 is provided at a height position that is the upper end of the three-dimensional air-conditioned space. Therefore, by directing the airflow from the air outlet 307A1 horizontally or obliquely upward, conditioned air can be blown out to a height higher than the upper end of the three-dimensional air-conditioned space. Therefore, even if the air outlet 307A1 is provided at a position close to the area where a person may exist, it is possible to prevent the conditioned air from blowing out toward the person. It is possible to avoid causing discomfort due to a feeling of draft.

Next, in step S13, the usage-side control device 121A1 performs control to reduce the rotational speed of the usage-side fan 9A1. As a result, the amount of conditioned air blown out from the air outlet 307A1 is reduced, thereby suppressing the generation of airflow in the vicinity of the air outlet 307A1. Therefore, it is possible to prevent people near the air outlet 307A1 from feeling uncomfortable due to a feeling of draft.

In step S14, the user-side control device 121A1 controls the wind direction plate drive mechanism 309A1 so that the wind direction of the conditioned air blown out from the air outlet 307A1 is obliquely downward. Thereby, when there is no person in the air-conditioned space of the usage unit 302A1, the conditioned air can be positively blown out toward the air-conditioned space.

The air conditioning system 100 of the present embodiment includes a plurality of air conditioners 300A and 300B that air-condition the same space by sharing the areas. In such a case, the area shared by the air conditioner 300A and the area shared by the air conditioner 300B are not necessarily separated by a wall. Therefore, for example, if the number of rotations of the user side fan 9A1 is reduced only based on a decrease in the temperature difference of the user unit 302A1 of the air conditioner 300A, the performance of the user unit 302A1 will be reduced, It may take a long time for the temperature difference of the utilization unit 302B1 of the air conditioner 300B to reach the target value. Therefore, in the present embodiment, all of the user-side fans 9A1, 9A2, 9B1, 9B2 of the air conditioners 300A and 300B operate during the period from when the air conditioners 300A and 300B are activated until the predetermined condition is satisfied. It is designed to prohibit a decrease in the number of revolutions. The predetermined condition is that the temperature difference between all the usage units 302A1, 302A2, 302B1, 302B2 of the air conditioners 300A and 300B is equal to or less than the threshold temperature difference. In other words, all of the usage side fans 9A1, 9A2, 9B1, The rotation speed of 9B2 is either maintained as it is or changed to be higher. During the above period, for example, all of the user-side fans 9A1, 9A2, 9B1, and 9B2 are set to the "strong" rotation speed setting level.

FIG. 10 is a flowchart showing an example of the flow of control executed by system controller 110 of air conditioning system 100 according to the present embodiment. The control shown in FIG. 10 is executed when the air conditioners 300A and 300B are activated. When the air conditioners 300A and 300B can share the temperature difference information of each usage unit, the control shown in FIG. good too.

In step S21 of FIG. 10, the system controller 110 determines whether or not the temperature difference between all the usage units 302A1, 302A2, 302B1, 302B2 of the air conditioners 300A and 300B is equal to or less than the threshold temperature difference. . If the temperature differences among all the usage units 302A1, 302A2, 302B1, 302B2 are equal to or less than the threshold temperature difference, the process proceeds to step S22; otherwise, the process proceeds to step S23.

In step S22, the system controller 110 permits both of the air conditioners 300A and 300B to control the rotation speed of the user-side fan to decrease. As a result, the processes of steps S5 to S7 in FIG. 5 are executed as they are in both air conditioners 300A and 300B. That is, in each of the air conditioners 300A and 300B, the rotation speed setting level of the usage-side fan of the representative usage unit is set to "high", and the rotation speed of the usage-side fan of the usage units other than the representative usage unit is It decreases according to the temperature difference of the utilization unit.

In step S23, the system controller 110 prohibits both of the air conditioners 300A and 300B from controlling the rotation speed of the user-side fan to decrease. As a result, neither of the air conditioners 300A and 300B executes control to reduce the rotation speed of the user-side fan. For example, in a certain user-side fan, if the rotation speed to be set in step S7 in FIG. 5 is lower than the current rotation speed, the current rotation speed is maintained. Therefore, the rotation speeds of all the user-side fans of the air conditioners 300A and 300B are maintained as they are, or become higher than the original rotation speeds. The determination in step S21 is repeated at predetermined time intervals until the temperature differences among all the usage units 302A1, 302A2, 302B1, and 302B2 are equal to or less than the threshold temperature difference.

According to the present embodiment, when the same space is air-conditioned by a plurality of air conditioners 300A and 300B, the time required for the temperature difference of some of the usage units to reach the target value It is possible to avoid an increase in the temperature difference between the units in use. Therefore, comfort can be improved.

As described above, the air conditioner 300A according to the present embodiment includes the compressor 1, the heat source side heat exchanger 3 functioning as a condenser, the plurality of user side pressure reducing devices 7A1 and 7A2 (an example of a plurality of pressure reducing devices ), and a plurality of usage-side heat exchangers 8A1 and 8A2 that function as evaporators, a refrigerant circuit 20 that circulates the refrigerant, and a plurality of usage-side heat exchangers 8A1 and 8A2 that supply air to each of the plurality of usage-side heat exchangers 8A1 and 8A2. Equipped with side fans 9A1 and 9A2 (an example of a plurality of fans), and a plurality of usage units 302A1 and 302A2 respectively accommodating the plurality of usage side heat exchangers 8A1 and 8A2 and the plurality of usage side fans 9A1 and 9A2. . A first usage unit (for example, a usage unit other than the representative usage unit) that is one of the plurality of usage units 302A1 and 302A2 is a first usage side heat exchanger that is one of the plurality of usage side heat exchangers 8A1 and 8A2. and a first fan, which is one of the plurality of user-side fans 9A1 and 9A2. A temperature difference between the plurality of usage units 302A1 and 302A2 is defined as a value obtained by subtracting the set temperature, which is the target value of the temperature, from the temperature of the air-conditioned space of each of the plurality of usage units 302A1 and 302A2. At this time, when the temperature difference of the first usage unit is a first value (for example, +0.5° C. or more), the first blower is driven at a first rotation speed (for example, rotation speed f3). If the temperature difference of one usage unit is a second value smaller than the first value (eg, −0.5° C. or more and less than 0° C.), a second rotation speed lower than the first rotation speed (eg, It is driven at the rotational speed f1) (see step S7 in FIG. 5 and FIG. 6). In the refrigerant circuit 20, the degree of superheat of the refrigerant flowing out from each of the plurality of usage-side heat exchangers 8A1 and 8A2 is set when the temperature difference of the first usage unit is the first value and when the temperature difference of the first usage unit is the first value. In any of the cases where the value is 2, it is maintained in the range of higher than 0° C. and lower than 5° C. (see step S1 in FIG. 5).

According to this configuration, the rotation speed of the first fan can be reduced based on the temperature difference of the first usage unit while maintaining the refrigerant circuit 20 in a state of high operating efficiency. Thereby, the energy required for the operation of the first blower can be reduced while suppressing the energy required for the operation of the refrigerant circuit 20 . Therefore, according to the present embodiment, it is possible to improve the energy saving performance of the air conditioner 300A.

In addition, the air conditioner 300A according to the present embodiment further includes outlets 307A1 and 307A2 that are provided facing the air-conditioned space and that blow out the conditioned air from the first usage unit to the air-conditioned space. The outlets 307A1 and 307A2 are arranged at a position lower than the ceiling 501a of the air-conditioned space. According to this configuration, even if the number of rotations of the first blower decreases, the conditioned air can reach the height at which people are present in the air-conditioned space.

In addition, in air conditioner 300A according to the present embodiment, outlets 307A1 and 307A2 may be provided on the surface of wall or pillar 504A1 facing the air-conditioned space. Moreover, in the air conditioner 300A according to the present embodiment, the first usage unit may be of a floor type in which the housing is provided with an outlet for blowing out the conditioned air.

Air conditioner 300A according to the present embodiment further includes human sensors 310A1 and 310A2 that detect the presence of people in the air-conditioned space. When the presence of a person is detected by the human sensors 310A1 and 310A2, the wind direction of the conditioned air blown from the outlets 307A1 and 307A2 is set horizontally or upward (see step S12 in FIG. 9). . When the human sensors 310A1 and 310A2 do not detect the presence of a person, the wind direction of the conditioned air blown from the outlets 307A1 and 307A2 is set downward from the horizontal direction (see step S14 in FIG. 9). According to this configuration, it is possible to prevent the conditioned air from blowing out toward the person, so it is possible to avoid the discomfort caused by the feeling of draft.

Air conditioner 300A according to the present embodiment further includes human sensors 310A1 and 310A2 that detect the presence of people in the air-conditioned space. When the presence of a person is detected by the human sensors 310A1 and 310A2, the first blower is driven at a lower rotational speed than when the presence of a person is not detected by the human sensors 310A1 and 310A2 (step S13 reference). According to this configuration, it is possible to avoid discomfort caused by a feeling of draft to people near the outlets 307A1 and 307A2.

In addition, in the air conditioner 300A according to the present embodiment, the plurality of user-side fans 9A1 , 9A2 (for example, the user-side fan of the representative use unit) is driven at the maximum control speed (for example, the speed f3) (see step S6 in FIG. 5). According to this configuration, it is possible to increase the capacity of at least one utilization unit while suppressing the energy required for operating the refrigerant circuit 20 .

Further, in the air conditioner 300A according to the present embodiment, when the temperature difference of the first usage unit becomes a third value smaller than the second value, the first fan rotates at the second rotation speed or less. is alternately repeated (for example, operation at the rotation speed setting level “weak/stop”). According to this configuration, the air in the air-conditioned space can be sucked into the usage unit while suppressing heat exchange in the usage-side heat exchanger. Therefore, the temperature of the air-conditioned space can be detected by the temperature sensor that detects the intake air temperature.

Further, in the air conditioner 300A according to the present embodiment, the frequency of the compressor 1 is the maximum value among the temperature differences between the plurality of usage units 302A1 and 302A2, or It is controlled based on the temperature difference of the utilization unit having the utilization side heat exchanger with the largest capacity (see steps S2 to S4 in FIG. 5). According to this configuration, frequent fluctuations in the frequency of the compressor 1 can be suppressed, so that the operating state of the air conditioner 300A can be stably maintained.

The air conditioning system 100 according to the present embodiment includes a plurality of air conditioners 300A and 300B that share and air-condition the same space, and a system controller 110 that controls the plurality of air conditioners 300A and 300B. . Each of the plurality of air conditioners 300A and 300B is an air conditioner according to the present embodiment. The system controller 110 determines that the temperature difference between all the plurality of usage units 302A1, 302A2, 302B1, 302B2 of the plurality of air conditioners 300A, 300B after the plurality of air conditioners 300A, 300B are activated is equal to or less than the threshold temperature difference. It is configured to prohibit a decrease in the number of rotations of the plurality of user-side fans 9A1, 9A2, 9B1, and 9B2 during the period until it reaches (see step S23 in FIG. 10). According to this configuration, it is possible to prevent the temperature difference of some of the usage units from increasing in time until the temperature difference reaches the target value, and the temperature difference of some of the usage units from increasing.

Embodiment 2.
An air conditioner and an air conditioning system according to Embodiment 2 of the present invention will be described. In the first embodiment, the opening degrees of the user-side depressurizing devices 7A1 and 7A2 are controlled based on the degrees of superheat of the user-side heat exchangers 8A1 and 8A2, respectively. The degrees of opening of 7A1 and 7A2 are controlled based on the degree of supercooling of the heat source side heat exchanger 3 . In an air conditioner with a small number of usage units, the degree of opening of the usage side pressure reducing devices 7A1 and 7A2 may be controlled based on the degree of subcooling of the heat source side heat exchanger 3 as in this embodiment. The configurations of the air conditioners 300A and 300B and the air conditioning system 100 of the present embodiment are the same as those of the first embodiment.

FIG. 11 is a flowchart showing an example of the control flow of the air conditioner 300A executed by the heat source side control device 101A of the air conditioning system 100 according to the present embodiment. Note that the control shown in FIG. 11 may be executed by either the user-side control device 121A1, the user-side control device 121A2, or the system controller 110. FIG. The control of the air conditioner 300B executed by the heat source side control device 101B or the like is the same as the control of the air conditioner 300A, so the explanation is omitted. In the following explanation, it is assumed that all the usage units are in cooling operation or stopped.

In step S31 of FIG. 11, the target degree of supercooling of the heat source side heat exchanger 3 of the air conditioner 300A is set to a relatively low value higher than 0° C. and 10° C. or lower (for example, 5° C.). If the supercooling degree target value has already been set, the set supercooling degree target value is maintained as it is, or the supercooling degree target value is changed within a range higher than 0 ° C and 10 ° C or less. . The opening degrees of the user-side decompression devices 7A1 and 7A2 are controlled so that the degree of supercooling of the heat source-side heat exchanger 3 approaches the target value of the degree of supercooling. For example, based on the degree of supercooling of the heat source side heat exchanger 3, the total opening degree of the user side decompression devices 7A1 and 7A2 is calculated. Then, based on the total opening degree of the user side depressurizing devices 7A1 and 7A2 and the weighting of the opening degree of the user side depressurizing devices 7A1 and 7A2 calculated based on the ratio of the capacities of the user side heat exchangers 8A1 and 8A2 Then, the respective opening degrees of the user-side decompression devices 7A1 and 7A2 are calculated. By controlling the opening degrees of the user-side decompression devices 7A1 and 7A2, the degree of superheat of the refrigerant flowing out of the heat source-side heat exchanger 3 is maintained in the range of higher than 0°C and 10°C or lower. In general, the lower the subcooling degree target value of the heat source side heat exchanger, the higher the efficiency of the operation of the refrigerant circuit 20 and the lower the power consumption of the refrigeration cycle. The degree of supercooling of the heat source side heat exchanger 3 is calculated by subtracting the temperature detected by the temperature sensor 204 from the saturation temperature of the pressure detected by the pressure sensor 221 . Usually, the low degree of supercooling means that the degree of supercooling is higher than 0°C and 8°C or lower. Therefore, the target value of the degree of supercooling of the heat source side heat exchanger 3 is higher than 0°C and 8°C or lower so that the degree of supercooling of the heat source side heat exchanger 3 is maintained in the range of 0°C or higher and 8°C or lower. It is desirable to be set in the range of

Steps S32 to S38 are the same as steps S2 to S8 in FIG. 5, so description thereof will be omitted.

As described above, the air conditioner 300A according to the present embodiment includes the compressor 1, the heat source side heat exchanger 3 functioning as a condenser, the plurality of user side pressure reducing devices 7A1 and 7A2 (an example of a plurality of pressure reducing devices ), and a plurality of usage-side heat exchangers 8A1 and 8A2 that function as evaporators, a refrigerant circuit 20 that circulates the refrigerant, and a plurality of usage-side heat exchangers 8A1 and 8A2 that supply air to each of the plurality of usage-side heat exchangers 8A1 and 8A2. Equipped with side fans 9A1 and 9A2 (an example of a plurality of fans), and a plurality of usage units 302A1 and 302A2 respectively accommodating the plurality of usage side heat exchangers 8A1 and 8A2 and the plurality of usage side fans 9A1 and 9A2. . A first usage unit (for example, a usage unit other than the representative usage unit) that is one of the plurality of usage units 302A1 and 302A2 is a first usage side heat exchanger that is one of the plurality of usage side heat exchangers 8A1 and 8A2. and a first fan, which is one of the plurality of user-side fans 9A1 and 9A2. A temperature difference between the plurality of usage units 302A1 and 302A2 is defined as a value obtained by subtracting the set temperature, which is the target value of the temperature, from the temperature of the air-conditioned space of each of the plurality of usage units 302A1 and 302A2. At this time, when the temperature difference of the first usage unit is a first value (for example, +0.5° C. or more), the first blower is driven at a first rotation speed (for example, rotation speed f3). If the temperature difference of one usage unit is a second value smaller than the first value (eg, −0.5° C. or more and less than 0° C.), a second rotation speed lower than the first rotation speed (eg, It is driven at the rotational speed f1) (see step S7 in FIG. 5 and FIG. 6). In the refrigerant circuit 20, the degree of subcooling of the refrigerant flowing out of the heat source side heat exchanger 3 is the first value when the temperature difference of the first usage unit is the first value and the second value of the temperature difference of the first usage unit. In any case, the temperature is maintained in the range of higher than 0° C. and 10° C. or lower (see step S31 in FIG. 11).

According to this configuration, the rotation speed of the first blower can be reduced based on the temperature difference between the temperature of the air-conditioned space and the set temperature while maintaining the refrigerant circuit 20 in a highly efficient state. Thereby, the energy required for the operation of the first blower can be reduced while suppressing the energy required for the operation of the refrigerant circuit 20 . Therefore, according to the present embodiment, it is possible to improve the energy saving performance of the air conditioner 300A.

Each of the above embodiments can be implemented in combination with each other.

1 compressor, 2 four-way valve, 3 heat source side heat exchanger, 4 heat source side blower, 6A, 6B connection piping, 7A1, 7A2 user side pressure reducing device, 8A1, 8A2, 8B1, 8B2 user side heat exchanger, 9A1, 9A2 , 9B1, 9B2 user-side blower, 10A, 10B connection pipe, 11 accumulator, 12 bypass pressure reducing device, 13 subcooling heat exchanger, 14 bypass flow path, 20 refrigerant circuit, 100 air conditioning system, 101A heat source side control device, 102A Measurement unit 103A Calculation unit 104A Control unit 105A Storage unit 106A Communication unit 110 System controller 121A1, 121A2 User-side control device 122A1, 122A2 Measurement unit 123A1, 123A2 Calculation unit 124A1, 124A2 Control unit 125A1 , 125A2 storage unit, 126A1, 126A2 communication unit, 201, 203, 204, 205, 206A1, 206A2, 207A1, 207A2, 208A1, 208A2, 210, 211 temperature sensor, 221, 222 pressure sensor, 300A, 300B air conditioner, 301A, 301B heat source unit 302A1, 302A2, 302A3, 302Ai, 302B1, 302B2 utilization unit 307A1, 307A2, 307B1, 307B2 outlet 308A1, 308B1 inlet 309A1, 309A2 wind direction plate drive mechanism 310A1, 3 10A2, 310B1, 310B2 human sensor, 500 indoor space, 501 office, 501a ceiling, 501b floor, 502 corridor, 503 window, 504A1, 504A2, 504B1, 504B2 pillar.

Claims (15)

a refrigerant circuit that includes a compressor, a heat source side heat exchanger that functions as a condenser, a plurality of decompression devices, and a plurality of user side heat exchangers that function as evaporators, and circulates the refrigerant;
a plurality of blowers that supply air to the plurality of utilization-side heat exchangers, respectively;
a plurality of usage units each accommodating the plurality of usage-side heat exchangers and the plurality of fans;
with
A first usage unit, which is one of the plurality of usage units, includes a first usage-side heat exchanger, which is one of the plurality of usage-side heat exchangers, and a first fan, which is one of the plurality of fans. and contains
When a value obtained by subtracting a set temperature, which is a target value of the temperature, from the temperature of the air-conditioned space of each of the plurality of usage units is defined as the temperature difference between the plurality of usage units,
The first blower is driven at a first rotational speed when the temperature difference of the first usage unit is a first value, and the temperature difference of the first usage unit is smaller than the first value. if the value is 2, drive at a second rotation speed lower than the first rotation speed;
The degree of superheat of the refrigerant flowing out of each of the plurality of usage-side heat exchangers in the refrigerant circuit is the temperature difference when the temperature difference of the first usage unit is the first value and the temperature difference of the first usage unit. is the second value, maintained in the range of greater than 0°C and less than or equal to 5°C;
The frequency of the compressor is
The temperature difference is controlled based on the temperature difference of only the usage unit with the largest temperature difference among the plurality of usage units, or the temperature difference of only the usage unit having the usage side heat exchanger with the largest capacity among the plurality of usage units. air conditioner. a refrigerant circuit that includes a compressor, a heat source side heat exchanger that functions as a condenser, a plurality of decompression devices, and a plurality of user side heat exchangers that function as evaporators, and circulates the refrigerant;
a plurality of blowers that supply air to the plurality of utilization-side heat exchangers, respectively;
a plurality of usage units each accommodating the plurality of usage-side heat exchangers and the plurality of fans;
with
A first usage unit, which is one of the plurality of usage units, includes a first usage-side heat exchanger, which is one of the plurality of usage-side heat exchangers, and a first fan, which is one of the plurality of fans. and contains
When a value obtained by subtracting a set temperature, which is a target value of the temperature, from the temperature of the air-conditioned space of each of the plurality of usage units is defined as the temperature difference between the plurality of usage units,
The first blower is driven at a first rotational speed when the temperature difference of the first usage unit is a first value, and the temperature difference of the first usage unit is smaller than the first value. if the value is 2, drive at a second rotation speed lower than the first rotation speed;
In the refrigerant circuit, the degree of subcooling of the refrigerant flowing out of the heat source side heat exchanger is the same when the temperature difference of the first usage unit is the first value and when the temperature difference of the first usage unit is the first value. maintained in the range of greater than 0° C. and less than or equal to 10° C. in any of the cases where the value is 2;
The frequency of the compressor is
The temperature difference is controlled based on the temperature difference of only the usage unit with the largest temperature difference among the plurality of usage units, or the temperature difference of only the usage unit having the usage side heat exchanger with the largest capacity among the plurality of usage units. air conditioner. further comprising an outlet facing the air-conditioned space for blowing the conditioned air from the first usage unit into the air-conditioned space;
The air conditioner according to claim 1 or 2, wherein the outlet is arranged at a position lower than the ceiling of the air-conditioned space. 4. The air conditioner according to claim 3, wherein the outlet is provided on a surface of a wall or a pillar facing the space to be air-conditioned. 3. The air conditioner according to claim 1, wherein the first usage unit is of a floor standing type having a housing provided with an outlet for blowing out conditioned air. Further comprising a human sensor that detects the presence of a person in the air-conditioned space,
When the presence of a person is detected by the human sensor, the wind direction of the conditioned air blown out from the outlet is set horizontally or upward,
6. The airflow direction of the conditioned air blown from the air outlet is set downward from the horizontal direction when the presence of a person is not detected by the human sensor. air conditioner. Further comprising a human sensor that detects the presence of a person in the air-conditioned space,
According to any one of claims 3 to 6, when the presence of a person is detected by the human sensor, the first blower is driven at a lower rotational speed than when the presence of a person is not detected by the human sensor. The air conditioner according to any one of claims 1 to 3. When the first fan is driven at the first rotation speed and when the first fan is driven at the second rotation speed, at least one of the plurality of fans is The air conditioner according to any one of claims 1 to 7, which is driven at the maximum number of revolutions. The first blower is driven at a third rotation speed that is equal to or lower than the second rotation speed when the temperature difference of the first usage unit is equal to or lower than a third value smaller than the second value. and stop are alternately repeated. a refrigerant circuit that includes a compressor, a heat source side heat exchanger that functions as a condenser, a plurality of decompression devices, and a plurality of user side heat exchangers that function as evaporators, and circulates the refrigerant;
a plurality of blowers that supply air to the plurality of utilization-side heat exchangers, respectively;
a plurality of usage units each accommodating the plurality of usage-side heat exchangers and the plurality of fans;
with
A first usage unit, which is one of the plurality of usage units, includes a first usage-side heat exchanger, which is one of the plurality of usage-side heat exchangers, and a first fan, which is one of the plurality of fans. and contains
When a value obtained by subtracting a set temperature, which is a target value of the temperature, from the temperature of the air-conditioned space of each of the plurality of usage units is defined as the temperature difference between the plurality of usage units,
The first blower is driven at a first rotational speed when the temperature difference of the first usage unit is a first value, and the temperature difference of the first usage unit is smaller than the first value. if the value is 2, drive at a second rotation speed lower than the first rotation speed;
The degree of superheat of the refrigerant flowing out of each of the plurality of usage-side heat exchangers in the refrigerant circuit is the temperature difference when the temperature difference of the first usage unit is the first value and the temperature difference of the first usage unit. is the second value, maintained in the range of greater than 0°C and less than or equal to 5°C;
When the first fan is driven at the first rotation speed and when the first fan is driven at the second rotation speed, at least one of the plurality of fans is Air conditioner driven at maximum speed. a refrigerant circuit that includes a compressor, a heat source side heat exchanger that functions as a condenser, a plurality of decompression devices, and a plurality of user side heat exchangers that function as evaporators, and circulates the refrigerant;
a plurality of blowers that supply air to the plurality of utilization-side heat exchangers, respectively;
a plurality of usage units each accommodating the plurality of usage-side heat exchangers and the plurality of fans;
with
A first usage unit, which is one of the plurality of usage units, includes a first usage-side heat exchanger, which is one of the plurality of usage-side heat exchangers, and a first fan, which is one of the plurality of fans. and contains
When a value obtained by subtracting a set temperature, which is a target value of the temperature, from the temperature of the air-conditioned space of each of the plurality of usage units is defined as the temperature difference between the plurality of usage units,
The first blower is driven at a first rotational speed when the temperature difference of the first usage unit is a first value, and the temperature difference of the first usage unit is smaller than the first value. if the value is 2, drive at a second rotation speed lower than the first rotation speed;
In the refrigerant circuit, the degree of subcooling of the refrigerant flowing out of the heat source side heat exchanger is the same when the temperature difference of the first usage unit is the first value and when the temperature difference of the first usage unit is the first value. maintained in the range of greater than 0° C. and less than or equal to 10° C. in any of the cases where the value is 2;
When the first fan is driven at the first rotation speed and when the first fan is driven at the second rotation speed, at least one of the plurality of fans is Air conditioner driven at maximum speed. a refrigerant circuit that includes a compressor, a heat source side heat exchanger that functions as a condenser, a plurality of decompression devices, and a plurality of user side heat exchangers that function as evaporators, and circulates the refrigerant;
a plurality of blowers that supply air to the plurality of utilization-side heat exchangers, respectively;
a plurality of usage units each accommodating the plurality of usage-side heat exchangers and the plurality of fans;
with
A first usage unit, which is one of the plurality of usage units, includes a first usage-side heat exchanger, which is one of the plurality of usage-side heat exchangers, and a first fan, which is one of the plurality of fans. and contains
When a value obtained by subtracting a set temperature, which is a target value of the temperature, from the temperature of the air-conditioned space of each of the plurality of usage units is defined as the temperature difference between the plurality of usage units,
The first blower is driven at a first rotational speed when the temperature difference of the first usage unit is a first value, and the temperature difference of the first usage unit is smaller than the first value. if the value is 2, drive at a second rotation speed lower than the first rotation speed;
The degree of superheat of the refrigerant flowing out of each of the plurality of usage-side heat exchangers in the refrigerant circuit is the temperature difference when the temperature difference of the first usage unit is the first value and the temperature difference of the first usage unit. is the second value, maintained in the range of greater than 0°C and less than or equal to 5°C;
The first blower is driven at a third rotation speed that is equal to or lower than the second rotation speed when the temperature difference of the first usage unit is equal to or lower than a third value smaller than the second value. The air conditioner alternately repeats and stops. a refrigerant circuit that includes a compressor, a heat source side heat exchanger that functions as a condenser, a plurality of decompression devices, and a plurality of user side heat exchangers that function as evaporators, and circulates the refrigerant;
a plurality of blowers that supply air to the plurality of utilization-side heat exchangers, respectively;
a plurality of usage units each accommodating the plurality of usage-side heat exchangers and the plurality of fans;
with
A first usage unit, which is one of the plurality of usage units, includes a first usage-side heat exchanger, which is one of the plurality of usage-side heat exchangers, and a first fan, which is one of the plurality of fans. and contains
When a value obtained by subtracting a set temperature, which is a target value of the temperature, from the temperature of the air-conditioned space of each of the plurality of usage units is defined as the temperature difference between the plurality of usage units,
The first blower is driven at a first rotational speed when the temperature difference of the first usage unit is a first value, and the temperature difference of the first usage unit is smaller than the first value. if the value is 2, drive at a second rotation speed lower than the first rotation speed;
In the refrigerant circuit, the degree of subcooling of the refrigerant flowing out of the heat source side heat exchanger is the same when the temperature difference of the first usage unit is the first value and when the temperature difference of the first usage unit is the first value. maintained in the range of greater than 0° C. and less than or equal to 10° C. in any of the cases where the value is 2;
The first blower is driven at a third rotation speed that is equal to or lower than the second rotation speed when the temperature difference of the first usage unit is equal to or lower than a third value smaller than the second value. The air conditioner alternately repeats and stops. a plurality of air conditioners that share and air-condition the same space;
a system controller that controls the plurality of air conditioners;
with
Each of the plurality of air conditioners,
a refrigerant circuit that includes a compressor, a heat source side heat exchanger that functions as a condenser, a plurality of decompression devices, and a plurality of user side heat exchangers that function as evaporators, and circulates the refrigerant;
a plurality of blowers that supply air to the plurality of utilization-side heat exchangers, respectively;
a plurality of usage units each accommodating the plurality of usage-side heat exchangers and the plurality of fans;
with
A first usage unit, which is one of the plurality of usage units, includes a first usage-side heat exchanger, which is one of the plurality of usage-side heat exchangers, and a first fan, which is one of the plurality of fans. and contains
When a value obtained by subtracting a set temperature, which is a target value of the temperature, from the temperature of the air-conditioned space of each of the plurality of usage units is defined as the temperature difference between the plurality of usage units,
The first blower is driven at a first rotational speed when the temperature difference of the first usage unit is a first value, and the temperature difference of the first usage unit is smaller than the first value. if the value is 2, drive at a second rotation speed lower than the first rotation speed;
The degree of superheat of the refrigerant flowing out of each of the plurality of usage-side heat exchangers in the refrigerant circuit is the temperature difference when the temperature difference of the first usage unit is the first value and the temperature difference of the first usage unit. is the second value, the air conditioner is maintained in a range of higher than 0 ° C. and 5 ° C. or lower,
The system controller controls, during a period from when the plurality of air conditioners are activated until the temperature differences among all of the plurality of usage units of the plurality of air conditioners become equal to or less than a threshold temperature difference, the plurality of An air conditioning system configured to prohibit a reduction in the fan speed of the air conditioning system. a plurality of air conditioners that share and air-condition the same space;
a system controller that controls the plurality of air conditioners;
with
Each of the plurality of air conditioners,
a refrigerant circuit that includes a compressor, a heat source side heat exchanger that functions as a condenser, a plurality of decompression devices, and a plurality of user side heat exchangers that function as evaporators, and circulates the refrigerant;
a plurality of blowers that supply air to the plurality of utilization-side heat exchangers, respectively;
a plurality of usage units each accommodating the plurality of usage-side heat exchangers and the plurality of fans;
with
A first usage unit, which is one of the plurality of usage units, includes a first usage-side heat exchanger, which is one of the plurality of usage-side heat exchangers, and a first fan, which is one of the plurality of fans. and contains
When a value obtained by subtracting a set temperature, which is a target value of the temperature, from the temperature of the air-conditioned space of each of the plurality of usage units is defined as the temperature difference between the plurality of usage units,
The first blower is driven at a first rotational speed when the temperature difference of the first usage unit is a first value, and the temperature difference of the first usage unit is smaller than the first value. if the value is 2, drive at a second rotation speed lower than the first rotation speed;
In the refrigerant circuit, the degree of subcooling of the refrigerant flowing out of the heat source side heat exchanger is the same when the temperature difference of the first usage unit is the first value and when the temperature difference of the first usage unit is the first value. An air conditioner maintained in the range of higher than 0 ° C. and 10 ° C. or lower in any of the cases where the value is 2,
The system controller controls, during a period from when the plurality of air conditioners are activated until the temperature differences among all of the plurality of usage units of the plurality of air conditioners become equal to or less than a threshold temperature difference, the plurality of An air conditioning system configured to prohibit a reduction in the fan speed of the air conditioning system.

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