JP2013117360A - Air conditioning device and method - Google Patents

Abstract

The present invention is capable of cooling with low power consumption without introducing any additional equipment other than an air conditioner, and avoids blowing almost uncooled air into the room immediately after a compressor cycle.
A refrigerant circuit includes a first circulation path through which a refrigerant bypasses a pump via a compressor, a condenser, and an evaporator; and a refrigerant that bypasses the compressor via a pump, an evaporator, and a condenser. In addition to the two circulation paths, there is a bypass connecting the outlet of the pump and the inlet of the condenser. For this reason, the refrigerant circuit has a third circulation path in which the refrigerant passes through the pump, the condenser, and the bypass thereof, and does not pass through the compressor and the evaporator. The air conditioner starts a pump cycle in which the refrigerant is circulated through the third circulation path after the compressor cycle in which the refrigerant circulates the first circulation path is stopped, and then the refrigerant is circulated through the second circulation path. To do.
[Selection] Figure 1

Description

  The present invention relates to air conditioning.

  In order to construct a computer system, a computer (hereinafter referred to as a server) for communication, database, file management, etc. is required to receive and process a request. This type of server is installed in the server machine room for convenience of operation and management. Specifically, for example, a plurality of servers are stored in a server rack, and a plurality of server racks are installed in a server machine room (a room where servers are installed).

  The server generates a large amount of heat during operation, and it is necessary to keep the temperature in the server machine room below a predetermined temperature for stable operation. For this reason, an air conditioner for controlling the temperature of the server machine room is installed.

  In data centers having many server machine rooms, in recent years, there is an increasing demand for suppressing power consumption other than for servers, and air conditioning apparatuses are also required to have low power consumption.

  As an air conditioner for the entire server machine room, in general, a compressor, an outdoor heat exchanger (condenser), an expansion valve, and an indoor heat exchanger (evaporator) are sequentially connected by a refrigerant pipe to form a refrigeration cycle. A harmony device is used.

  However, the server machine room is sometimes operated at about 30 ° C. If the outside air temperature is lower than that, the refrigerant can be cooled without using the compressor by cooling and circulating the refrigerant directly with the outside air. Such a system that uses the cold heat of low-temperature outside air is called “free cooling”.

  In order to perform free cooling effectively, a system with a forced refrigerant circulation device is being developed. By using a pump for forced circulation, the server machine can be used with low power consumption compared to a refrigeration cycle using a compressor. The room can be cooled.

  For example, Patent Documents 1 and 2 and Non-Patent Document 1 are known as air conditioners.

  According to Patent Document 1, an air conditioning system is constructed in which cooling coils that pass cooling water from a refrigerator and cool air are connected in series to an air conditioner. Thereby, the temperature difference of the air which passes an air conditioning apparatus and a cooling coil can be enlarged, and, therefore, the reduction in power consumption of an air conditioning apparatus is anticipated.

  According to Patent Document 2 and Non-Patent Document 1, when the outside air temperature is lower than the room temperature, the compressor is bypassed, and the outdoor cold heat is transported indoors using another refrigerant circulation device. In this case, the refrigerant circulation device may have power enough to overcome the pipe loss, and can be cooled with low power consumption by circulation using a pump.

JP 2002-168479 A Japanese Patent Laid-Open No. 10-82566

Proceedings of the Japan Society of Mechanical Engineers (Part B), Vol. 67, No. 660 (2001-8), “Study on Improvement of Efficiency of Annual Cooling Package Air Conditioner with Indirect Outside Air Cooling Function”

  According to Patent Document 1, a sub device such as a cooling coil is required in addition to the air conditioner. For this reason, the construction of the system becomes complicated, and the introduction cost is high.

  According to Patent Document 2 and Non-Patent Document 2, when a cycle in which a pump for forced refrigerant circulation is added to a refrigeration cycle in which a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected by a refrigerant pipe, The refrigeration cycle that uses a compressor and the refrigeration cycle that uses a pump have greatly different refrigerant temperatures and pressures. Therefore, immediately after switching from the compressor cycle to the pump cycle, the air that is hardly cooled by the indoor unit for a certain period of time. May blow out. For this reason, it is desirable to improve control in cycle transients.

  The above problem may also be related to air conditioning in rooms other than the server machine room.

  The object of the present invention is to allow cooling with low power consumption without introducing any additional equipment other than the air conditioner, and to avoid blowing almost uncooled wind into the room immediately after the compressor cycle is stopped. There is to do.

  The refrigerant circuit includes a first circulation path in which the refrigerant bypasses the pump via the compressor, the condenser and the evaporator, and a second circulation path in which the refrigerant bypasses the compressor via the pump, the evaporator and the condenser In addition, it has a bypass connecting the outlet of the pump and the inlet of the condenser. For this reason, the refrigerant circuit has a third circulation path in which the refrigerant passes through the pump, the condenser, and the bypass thereof, and does not pass through the compressor and the evaporator. The air conditioner can switch between a refrigeration cycle (compressor cycle) for circulating the first circulation path through the refrigerant and a refrigeration cycle (pump cycle) for circulating the second circulation path through the refrigerant. After stopping the compressor cycle, the refrigerant is circulated through the third circulation path, and then the pump cycle is started.

  Cooling can be performed with low power consumption without introducing any additional equipment other than the air conditioner, and it is possible to avoid blowing almost uncooled wind into the room immediately after the compressor cycle is stopped.

The structural example of the air conditioning apparatus which concerns on Example 1 is shown. The structural example of the air conditioning apparatus which concerns on Example 2 is shown.

  An outline of the embodiment will be described.

  The air conditioner is, for example, an air conditioner for a computer, and includes a compressor, an evaporator, a condenser, and a pump, and the refrigerant does not pass through the pump according to the outside air temperature and the server machine room load. The compressor cycle, which is a refrigeration cycle via an evaporator and a condenser, and the pump cycle, which is a refrigeration cycle via which a refrigerant passes through a pump, an evaporator and a condenser without switching through the compressor, are switched. The air conditioner connects the pump outlet and the condenser and has an evaporator and a compressor bypass. After the compressor cycle is stopped, the air conditioner circulates the refrigerant from the pump outlet to the condenser through a bypass to make the refrigerant temperature sufficiently close to the outside air temperature. Thereafter, the air conditioner closes the bypass and operates the pump cycle. Thereby, the refrigerant having a low temperature can be circulated immediately after the pump cycle is started. As a result, it can be avoided that the refrigerant having a high temperature enters the evaporator immediately after the compressor cycle is stopped and the temperature of the blowout into the room temporarily rises.

  The compressor and the evaporator are provided in the indoor unit, and the condenser and the pump are provided in the outdoor unit, but the bypass is installed in the outdoor unit. Thereby, it is thought that the load of construction of an air conditioning apparatus is equivalent to the load of the general construction of attachment of an indoor unit and an outdoor unit.

  The bypass is provided with a pressure sensor and a restrictor. In addition, a pressure sensor is provided at the pump inlet. Thereby, the flow through which the refrigerant circulates to the condenser through the condenser, the pump, and the bypass (throttle device) can be formed. Therefore, the operation of the pump can be confirmed with the outdoor unit alone. That is, in order to check whether the pump is correctly connected, the differential pressure between the pressure sensor installed at the pump inlet and the pressure sensor installed at the bypass pipe is increased by rotating the pump with the above-mentioned restrictor set to an appropriate opening degree. Arise. By confirming whether the differential pressure is positive or negative, it is easy to determine whether the operation of the pump is correct, and the quality confirmation process at the production stage is facilitated.

  Several embodiments will be described below.

  FIG. 1 shows a configuration example of an air conditioner according to the first embodiment.

  The air conditioner includes an outdoor unit 6 and an indoor unit 7. The indoor unit 7 is installed in the server machine room, and the outdoor unit 6 is installed outside the server machine room (for example, outside the building having the server machine room).

  The air conditioner includes a compressor cycle (a refrigeration cycle in which a cooling operation is performed by returning to the compressor 1 through the refrigerant sequentially through the compressor 1, the condenser 2, the expansion valve 4, the evaporator 5, and the accumulator 16). And a pump cycle (a refrigeration cycle for performing a cooling operation by returning the refrigerant to the condenser 2 through the condenser 2, the forced refrigerant circulation pump 3, the expansion valve 4, and the evaporator 5 in order). That is, the air conditioner has a refrigerant circuit in which the compressor 1, the condenser 2, the pump 3, the expansion valve 4, the evaporator 5, and the accumulator 16 are connected in series and the refrigerant circulates. The refrigerant circuit includes a compressor 1, a condenser 2, an expansion valve 4, an evaporator 5, an accumulator 16, a first circulation path in which refrigerant circulates in order and bypasses the pump 3, a condenser 2, a pump 3, and an expansion A refrigerant is circulated in order through the valve 4 and the evaporator 5 and has a second circulation path that bypasses the compressor 1. In the compressor cycle, the refrigerant circulates through the first circulation path, and in the pump cycle, the refrigerant circulates through the second circulation path. In both cycles, the condenser 2, the expansion valve 4 and the evaporator 5 are shared.

  The indoor unit 7 includes an expansion valve 4, an evaporator 5, an accumulator 16, and a compressor 1, which are sequentially (in series) connected by refrigerant piping. A temperature sensor 14 and a pressure sensor 15 are provided between the outlet of the evaporator 5 and the accumulator 16 (for example, in the vicinity of the outlet of the evaporator 5). With these sensors, the refrigerant heating degree can be detected. Moreover, the bypass pipe 30 of the compressor 1 is provided in the indoor unit 7, and the compressor bypass valve 13 is provided in the middle. In the compressor cycle, the bypass valve 13 is closed by the indoor controller, so that the refrigerant passes through the compressor 1, and in the pump cycle, the bypass valve 13 is opened by the indoor controller, so that the refrigerant passes through the compressor 1. Without passing through the bypass pipe 30. The opening and closing of the bypass valve 13 may be actively performed by the indoor controller regardless of whether there is an instruction from the outdoor controller, or may be performed by the indoor controller in accordance with an instruction from the outdoor controller.

  The outdoor unit 6 includes a stop valve 19, a condenser 2, an excess refrigerant regulator 9, a forced refrigerant circulation pump 3, and a three-way valve 23, which are sequentially (in series) connected by refrigerant piping. In addition to the pump 3, the three-way valve 23 is connected to the indoor unit 7 and a bypass pipe 27 connected to the inlet of the condenser 2. That is, the refrigerant circuit has, in addition to the first and second circulation paths, a third circulation path in which the refrigerant circulates through the pump 3, the bypass pipe 27 and the condenser 2 and does not pass through the evaporator 5 and the compressor 1. . In the middle of the bypass pipe 27, a bypass pipe pressure sensor 24 and a restrictor 25 are provided.

  The air conditioner has a controller. The controller includes a first controller (hereinafter referred to as an indoor controller) (not shown) of the indoor unit 7 and a second controller (hereinafter referred to as an outdoor controller) (not shown) of the outdoor unit 6. The indoor controller and the outdoor controller can communicate with each other. For example, the outdoor controller notifies the indoor controller of a value (sensor detection value) detected by a sensor in the outdoor unit 6, and the indoor controller can switch the refrigeration cycle according to the sensor detection value.

  Silencers 12 are provided before and after the forced refrigerant circulation pump 3, whereby transmission of driving sound of the pump 3 is suppressed. Further, before and after the pump 3, a pump replacement blocking valve 20 is provided for closing a circuit before and after the pump when the pump is replaced. Further, since the pump 3 becomes a resistance during the operation of the compressor 1, there is a bypass pipe 29 that bypasses the pump 3 during the operation of the compressor 1, and a bypass valve 21 is provided in the middle of the bypass pipe 29. ing. The bypass valve 21 may be a check valve or a stop valve that performs control according to the operation of the air conditioner. In the pump cycle, the bypass valve 21 is closed by the outdoor controller, so that the refrigerant passes through the pump 3, and in the compressor cycle, the bypass valve 21 is opened by the outdoor controller, so that the refrigerant bypasses the pump 3 without passing through it. Via tube 29. The opening and closing of the bypass valve 21 may be actively performed by the outdoor controller regardless of whether there is an instruction from the indoor controller, or may be performed by the outdoor controller in accordance with an instruction from the indoor controller.

  The forced refrigerant circulation pump 3, the three-way valve 23 and the bypass pipe 27 are installed in the casing of the outdoor unit 6. Thereby, compared with the presence of these elements (pump 3 or the like) separately from the outdoor unit 6, the construction of the air conditioner is easy. This is because the construction is equivalent to the general construction of mounting indoor units and outdoor units.

  Further, at the inlet of the forced refrigerant circulation pump 3, a pump inlet pressure sensor (a sensor for detecting the pressure of the pump inlet refrigerant (a refrigerant entering the pump 3)) 10 and a pump inlet temperature sensor (a sensor for detecting the temperature of the pump inlet refrigerant). ) 11 is provided. The outdoor controller determines whether or not it is in the liquid phase state on the ph diagram from the detection values of the sensors 10 and 11 (the pump inlet refrigerant is pressure and temperature). Liquid phase recovery control. In the casing of the outdoor unit 6, an outdoor blower 8 and a drive / control device (not shown) for the forced refrigerant circulation pump 3 are further provided.

  The compressor cycle and the pump cycle are switched depending on the heat load and the outside air condition on the indoor unit 7 side. For example, during the compressor cycle, the cooling capacity that is exhibited varies depending on the heat load on the indoor unit 7 side and the outside air conditions. The indoor controller is detected by a load on the indoor side (for example, a load specified based on a value detected by a sensor or the like of the indoor unit 7) and an outdoor temperature condition (for example, a sensor of the outdoor unit 6). Calculated from the value received from the outdoor controller), the refrigeration cycle can be changed from the compressor cycle to the pump cycle if the cooling capacity is sufficient to cover the load in the room. Switch to. For example, the switching instruction is sent from the indoor controller to the outdoor controller, and switching from the compressor cycle to the pump cycle is performed by the outdoor controller.

  Immediately after the compressor cycle is stopped, when the temperature of the refrigerant at the pump inlet is high and the refrigeration cycle is simply switched from the compressor cycle to the pump cycle, as described above, to the server machine room of the air conditioner immediately after the pump cycle is started. The blowout temperature of becomes higher.

  Therefore, in this embodiment, when the compressor cycle is switched to the pump cycle, the outdoor controller 19 is closed after the compressor 1 is stopped by the outdoor controller, and the connection of the three-way valve 23 is connected to the condenser 2. It is switched to the bypass pipe 27. Thereafter, the forced refrigerant circulation pump 3 is activated by the outdoor controller. Thereby, the refrigerant in the outdoor unit 6 circulates to the condenser 2 through the condenser 2, the surplus refrigerant regulator 9, the forced refrigerant circulation pump 3 and the three-way valve 23. At this time, the outdoor controller cools the refrigerant while controlling the outdoor blower 8 in the range where the values detected by the sensors 10 and 11 (pressure and temperature of the pump inlet refrigerant) are in the liquid phase state on the ph diagram. Then, after the temperature of the refrigerant at the pump inlet (the temperature detected by the sensor 11) has sufficiently approached the outside air temperature (the temperature detected by the outside air temperature sensor (not shown) of the outdoor unit 6) (for example, After the temperature of the pump inlet refrigerant approaches the outside air temperature so that the difference between the temperature of the pump inlet refrigerant and the outside air temperature becomes less than a predetermined value), connect the three-way valve 23 from the bypass pipe 27 to the indoor unit side (condensation). For example, the stop valve 19 is opened at the same time, and the operation is switched to the cooling operation in the pump cycle. The refrigerant is circulated to the condenser 2 through the condenser 2, the forced refrigerant circulation pump 3, the expansion valve 4 and the evaporator 5. Thereby, cold air is blown out from the evaporator 5 of the indoor unit 7 into the server machine room. Whether the temperature of the refrigerant at the pump inlet has sufficiently approached the outside air temperature may be determined from the detection values from the sensor 11 and the outside air temperature sensor as described above, or whether a certain time has elapsed since the compressor cycle was stopped. It may be judged.

  The bypass pipe 27 that connects the three-way valve 23 and the condenser 2 can also be used for an operation check test of the outdoor unit 6 that incorporates the forced refrigerant circulation pump 3. In this case, with the outdoor unit 6 alone, the surplus refrigerant regulator 9 is filled with the refrigerant so that the liquid refrigerant can be stored in a predetermined ratio (for example, about 70%) with respect to the capacity of the regulator 9, and the stop valve 19 is Closed and switched so that the three-way valve 23 is connected to the condenser 2.

  The outdoor controller operates the forced refrigerant circulation pump 3 while rotating the outdoor blower 8 with the throttle 25 set to an appropriate opening degree, so that the pump inlet pressure sensor 10 and the bypass pipe pressure sensor 24 are connected to the front and rear of the pump. The pressure can be measured. Therefore, the pump operation can be confirmed (confirmation of forward / reverse rotation, rated head, etc.) from the pump pressure.

  That is, when there is no load, there is no difference in pressure between the inlet and the outlet of the pump 3, and therefore, whether or not the outlet pressure is higher than the inlet pressure of the pump 3 during quality check (that is, the pump 3 is normal). Whether or not there is no load. The throttle 25 can generate a differential pressure between the pressure sensor 10 installed at the pump inlet and the pressure sensor 24 installed at the bypass pipe 27 in the operation check before the start of operation. In addition, although the operation frequency of the pump 3 may be narrow, it can be expected that the narrower 25 compensates for the narrow frequency during operation.

  Example 2 will be described below. At that time, differences from the first embodiment will be mainly described, and description of common points with the first embodiment will be omitted or simplified.

  FIG. 2 shows a configuration example of the air-conditioning apparatus according to the second embodiment.

  In the first embodiment, the heat exchanger (cooler) 2 of the outdoor unit 6 is a single unit. However, in the second embodiment, the refrigerant does not pass through the main heat exchanger (condenser) 2 and is a sub heat exchanger. A circulation path through the (supercooler) 26 is provided. Hereinafter, Example 2 will be described in detail.

  According to the compressor cycle and the pump cycle of the second embodiment, the subcooler 26 is added to the compressor cycle and the pump cycle of the first embodiment, respectively. Specifically, in the compressor cycle of the second embodiment, the cooling operation is performed by sequentially passing the refrigerant through the compressor 1, the condenser 2, the supercooler 26, the expansion valve 4, the evaporator 5 and the accumulator 16. This is a refrigeration cycle to be performed. The pump cycle of the second embodiment performs a cooling operation by sequentially passing the refrigerant through the condenser 2, the supercooler 26, the forced refrigerant circulation pump 3, the expansion valve 4 and the evaporator 5. It is a refrigeration cycle. In both cycles, the condenser 2, the expansion valve 4, the evaporator 5 and the supercooler 26 are shared.

  In the outdoor unit 6, the stop valve 19, the condenser 2, the surplus refrigerant regulator 9, the supercooler 26, the forced refrigerant circulation pump 3, and the three-way valve 23 are sequentially (in series) connected by refrigerant piping. The three-way valve 23 is connected to the indoor unit 7 and a bypass pipe 27 connected immediately before the surplus refrigerant regulator 9. The bypass pipe pressure sensor 24 and the restrictor 25 described above are provided in the middle of the bypass pipe 27 connected between the three-way valve 23 and the surplus refrigerant regulator 9.

  The forced refrigerant circulation pump 3, the three-way valve 23 and the bypass pipe 27 are installed in the casing of the outdoor unit 6.

  In the second embodiment, when the compressor cycle is switched to the pump cycle, the compressor 1 is stopped, and then the stop valve 19 is closed, and the connection of the three-way valve 23 is switched to the bypass rod 27. Thereafter, the forced refrigerant circulation pump 3 is activated. Thereby, the refrigerant in the outdoor unit 6 circulates to the surplus refrigerant regulator 9 via the surplus refrigerant regulator 9, the supercooler 26, the forced refrigerant circulation pump 3 and the three-way valve 23. At this time, the outdoor controller cools the refrigerant while controlling the outdoor blower 8 in the range where the values detected by the sensors 10 and 11 (pressure and temperature of the pump inlet refrigerant) are in the liquid phase state on the ph diagram. The outdoor controller then switches the connection of the three-way valve 23 to the indoor unit 7 after the temperature of the refrigerant at the inlet of the pump has sufficiently approached the outside air temperature, for example, opens the stop valve 19 at the same time, and performs the cooling operation in the pump cycle. And switch. Thereby, the refrigerant is circulated to the condenser 2 through the condenser 2, the forced refrigerant circulation pump 3, the expansion valve 4 and the evaporator 5, and cold air blows out from the evaporator 5 into the room.

  The bypass pipe 27 connecting the three-way valve 23 and the surplus refrigerant regulator 9 can be used for the operation confirmation test application of the outdoor unit 6 incorporating the forced refrigerant circulation pump 3 as in the first embodiment. In this case, with the outdoor unit 6 alone, the surplus refrigerant regulator 9 is filled with refrigerant, the stop valve 19 is closed, and the connection of the three-way valve 23 is switched to the surplus refrigerant regulator 9.

  Although several embodiments have been described above, the present invention is not limited to these embodiments. For example, a temperature sensor for detecting the temperature of the refrigerant discharged from the pump 3 may be provided. The air conditioning apparatus can also be applied to air conditioning in rooms other than the server machine room. That is, the present invention is not limited to an air conditioner for a computer.

1: compressor, 2: condenser, 3: pump, 4: expansion valve, 5: evaporator, 6: outdoor unit casing, 7: indoor unit casing, 8: outdoor blower, 9: surplus refrigerant regulator, 10: pump inlet pressure sensor, 11: pump inlet temperature sensor, 12: silencer, 13: compressor bypass valve, 14: evaporator outlet temperature sensor, 15: pressure sensor, 16: accumulator, 17: compressor outlet pressure sensor, 18: Indoor blower, 19: Stop valve, 20: Pump replacement blocking valve, 21: Pump bypass valve, 22: Compressor outlet check valve, 23: Three-way valve, 24: Bypass soot pressure sensor, 25: Throttle 26: Supercooler 27: Bypass pipe 29: Bypass pipe 30: Bypass pipe

Claims (8)

The refrigerant included a first circulation path for bypassing the pump via the evaporator, the compressor and the condenser, and a second circulation path for the refrigerant bypassing the compressor via the evaporator, the condenser and the pump. A refrigerant circuit;
A controller that switches between a compressor cycle that is a refrigeration cycle that circulates the first circulation path through the refrigerant and a pump cycle that is a refrigeration cycle that circulates the second circulation path through the refrigerant;
The refrigerant circuit further includes a third circulation path;
The third circulation path has a bypass connecting the outlet of the pump and the inlet of the condenser, and the refrigerant passes through the pump, the condenser and the bypass, and does not pass through the compressor and the evaporator.
The controller causes the refrigerant to circulate through the third circulation path after the compressor cycle is stopped, and then starts the pump cycle;
Air conditioner. The air conditioner according to claim 1,
A throttling device is provided for adjusting the amount of refrigerant flowing through the bypass of the third circulation path;
Air conditioner. It is an air conditioning apparatus of Claim 2, Comprising:
A first pressure sensor for detecting the pressure of the refrigerant entering the pump;
An air conditioner having a second pressure sensor for detecting the pressure of the refrigerant flowing through the bypass. The air conditioner according to claim 1,
After the compressor cycle is stopped, the controller circulates the refrigerant through the third circulation path for a certain period of time, or until the temperature of the refrigerant passing through the pump decreases to a certain temperature. After circulating the third circulation path, starting the pump cycle;
Air conditioner. It is an air conditioning apparatus of any one of Claims 1 thru | or 4, Comprising:
The pump, the condenser and the bypass are provided in the same housing;
Air conditioner. It is an air conditioning apparatus of Claim 5, Comprising:
The compressor and the evaporator are provided in an indoor unit,
The housing is a housing of an outdoor unit.
Air conditioner. It is an air conditioning apparatus of Claim 6, Comprising:
The controller is composed of first and second controllers that communicate with each other,
The first controller is provided in the indoor unit,
The second controller is provided in the casing of the outdoor unit,
Air conditioner. After stopping the compressor cycle, which is a refrigeration cycle in which the refrigerant circulates in the first circulation path that bypasses the pump via the evaporator, the compressor and the condenser, the refrigerant passes through the pump and the condenser, and then the compressor And a third circulation path that does not pass through the evaporator is circulated to the refrigerant, and then the refrigerant passes through the second circulation path that bypasses the compressor via the evaporator, the condenser, and the pump. Start a pump cycle,
Air conditioning method.

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