JP2009079815A - Heat source side unit, air-conditioner, and air conditioning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air-conditioner wherein heat exchange is made between water and coolant while avoiding an excessive reduction of a coolant condensing temperature during cooling operation. <P>SOLUTION: The plurality of air-conditioners 10 each comprise an outdoor unit 4 having a compressor 41 for compressing the coolant, and outdoor heat exchangers 51, 52 for making heat exchange between circulating water supplied from a cooling tower 2 and the coolant. The outdoor unit 4 includes a bypass pipe 60 for bypassing both ends of the outdoor heat exchangers 51, 52. A microcomputer 50A controls all or part of the coolant to flow in the bypass pipe 60 instead of the outdoor heat exchangers 51, 52 when there is a small difference between coolant pressure on the discharge side of the compressor 41 and that on the suction side thereof during cooling operation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat source side unit of an air conditioner, an air conditioner, and an air conditioner system including the air conditioner.

Conventionally, it has been pointed out that the refrigerant condensing temperature may be excessively lowered during the cooling operation of the air conditioner, thereby causing liquid compression of the compressor. Therefore, a measure for avoiding a decrease in the refrigerant condensing temperature in the heat source side unit has been proposed. For example, in an air-cooled heat source side unit that exchanges heat between the outside air and the refrigerant, a decrease in the refrigerant condensing temperature is detected and air cooling is performed. A method for reducing the speed of a blower has been proposed (see, for example, Patent Document 1).
JP 05-256528 A

The method disclosed in Patent Document 1 can be applied only in an air conditioner including an air-cooled heat exchanger that exchanges heat between outside air and refrigerant. For example, water is used as a heat source and a cold heat source, and the water and the refrigerant are used. It cannot be applied to a configuration in which heat is exchanged between another type of heat source and a refrigerant, such as an air conditioner that exchanges heat with the refrigerant.
Accordingly, an object of the present invention is to avoid an excessive decrease in the refrigerant condensing temperature during cooling operation in an air conditioner or the like that exchanges heat between water and the refrigerant.

In order to solve the above problems, the present invention provides a heat source side unit of an air conditioner including a compressor that compresses a refrigerant, and a heat source side heat exchanger that exchanges heat between water supplied from the outside and the refrigerant. A bypass pipe for bypassing the heat source side heat exchanger is provided, and a part of the refrigerant discharged from the compressor when a difference in refrigerant pressure between the discharge side and the suction side of the compressor is small during cooling operation Or the control part which controls so that all may be flowed to the said bypass pipe, without flowing to the said heat source side heat exchanger is provided, It is characterized by the above-mentioned.
According to this configuration, the heat source side heat exchanger that exchanges heat between the water supplied from the outside and the refrigerant and the bypass pipe that bypasses the heat source side heat exchanger are provided, and the discharge side of the compressor during the cooling operation When the difference in refrigerant pressure from the suction side is small, part or all of the refrigerant is allowed to flow through the bypass pipe. As a result, when the refrigerant condensing temperature is excessively lowered due to the temperature of water supplied from the outside being too low, and the difference in refrigerant pressure between the discharge side and the suction side of the compressor becomes small, the bypass pipe The hot gas discharged from the compressor is passed through. As a result, it is possible to avoid further decrease in the refrigerant condensing temperature and to quickly recover the refrigerant condensing temperature to a suitable temperature, even if the temperature of the water supplied from the outside to the heat source side heat exchanger is low. Stable cooling operation can be realized.

In the above-described configuration, the control unit is configured such that a difference between a refrigerant pressure in the refrigerant line connected to the discharge side of the compressor and a refrigerant pressure in the refrigerant line connected to the suction side of the compressor is a preset pressure difference. If the temperature of the refrigerant is lower than the value, a part or all of the refrigerant discharged from the compressor may be controlled to flow through the bypass pipe without flowing through the heat source side heat exchanger.
In this case, when the difference between the refrigerant pressure in the refrigerant line connected to the discharge side of the compressor and the refrigerant pressure in the refrigerant line connected to the suction side of the compressor falls below a preset pressure difference, the compressor Since part or all of the refrigerant discharged from the refrigerant flows through the bypass pipe instead of flowing through the heat source side heat exchanger, the refrigerant condensation temperature can be quickly coped with when the refrigerant condensation temperature tends to decrease excessively. The refrigerant condensing temperature can be quickly recovered to a suitable temperature.

Further, in the above configuration, a valve that distributes the refrigerant to the heat source side heat exchanger and the bypass pipe is provided, and the control unit adjusts a difference in refrigerant pressure between the discharge side and the suction side of the compressor during cooling operation. Based on this, it is possible to perform control for setting a ratio of distributing the refrigerant to the heat source side heat exchanger and the bypass pipe by the valve.
In this case, the control unit controls the valve that distributes the refrigerant to the heat source side heat exchanger and the bypass pipe, thereby setting the ratio of distributing the refrigerant by this valve, so that the flow of the refrigerant can be finely adjusted. The stable cooling operation can be realized by recovering the influence caused by the temperature of the heat source water being too low.

Moreover, in order to solve the said subject, the air conditioning apparatus of this invention is a heat source side provided with the compressor which compresses a refrigerant | coolant, and the heat source side heat exchanger which heat-exchanges the water supplied from the outside and the said refrigerant | coolant. In the air conditioner configured to include a unit, the heat source side unit is provided with a bypass pipe that bypasses the heat source side heat exchanger, and further, refrigerant between the discharge side and the suction side of the compressor during cooling operation A control unit is provided that performs control so that a part or all of the refrigerant discharged from the compressor flows through the bypass pipe without flowing through the heat source side heat exchanger when the pressure difference is small. And
According to this configuration, the heat source side unit including the heat source side heat exchanger that exchanges heat between the water supplied from the outside and the refrigerant and the bypass pipe that bypasses the heat source side heat exchanger is compressed during the cooling operation. When the refrigerant pressure difference between the discharge side and suction side of the machine is small, part or all of the refrigerant flows through the bypass pipe, so the refrigerant condensing temperature is reduced because the temperature of water supplied from outside is too low. When the pressure decreases excessively and the difference in refrigerant pressure between the discharge side and the suction side of the compressor becomes small, hot gas discharged from the compressor is flowed through the bypass pipe. As a result, it is possible to avoid further decrease in the refrigerant condensing temperature and to quickly recover the refrigerant condensing temperature to a suitable temperature, even if the temperature of the water supplied from the outside to the heat source side heat exchanger is low. Stable cooling operation can be realized.

Moreover, in order to solve the said subject, the air conditioning system of this invention is the heat source side heat exchange which makes the heat source water supply part which supplies heat source water heat-exchange the compressor which compresses a refrigerant | coolant, and the said heat source water and the said refrigerant | coolant. A plurality of air conditioners including a heat source side unit provided with a heater are connected, and the heat source side unit of the air conditioner is provided with a bypass pipe that bypasses the heat source side heat exchanger, during cooling operation When a difference in refrigerant pressure between the discharge side and the suction side of the compressor is small, a part or all of the refrigerant discharged from the compressor is allowed to flow to the bypass pipe without flowing to the heat source side heat exchanger. A control unit for performing control is provided.
According to this configuration, the heat source side unit including the heat source side heat exchanger that exchanges heat between the heat source water supplied from the heat source water supply unit and the refrigerant, and the bypass pipe that bypasses the heat source side heat exchanger, During the cooling operation of the air conditioner, when the refrigerant pressure difference between the discharge side and the suction side of the compressor is small, part or all of the refrigerant is passed through the bypass pipe. As a result, when the refrigerant condensing temperature is excessively lowered due to the temperature of the heat source water being too low, and the difference in refrigerant pressure between the discharge side and the suction side of the compressor becomes small, compression is performed via the bypass pipe. Hot gas discharged from the machine flows. Thereby, by controlling the operation of the heat source side unit, it is possible to avoid a further decrease in the refrigerant condensing temperature and quickly recover the refrigerant condensing temperature to a suitable temperature. For this reason, even if the heat source water supply unit does not change the supply state of the heat source water, a stable cooling operation can be realized by controlling the operation of the air conditioner that performs the cooling operation. Therefore, for example, when a plurality of air conditioners perform a heating operation in the cold season and only some of the air conditioners perform a cooling operation, the operation of the air conditioner performing the heating operation or the supply of heat source water Without affecting the operation of the unit, the air conditioner that performs the cooling operation avoids an excessive decrease in the refrigerant condensing temperature and can stably perform the cooling operation.

  According to the present invention, when the refrigerant condensing temperature is excessively lowered during the cooling operation, the refrigerant condensing temperature can be prevented from further lowering, and the refrigerant condensing temperature can be quickly recovered to a suitable temperature. Cooling operation can be realized.

FIG. 1 is a diagram showing an example of an installation state of an air conditioning system 1 to which the present invention is applied.
For example, as shown in FIG. 1, the air conditioning system 1 is configured by connecting a plurality of air conditioning apparatuses installed in various places of a building 200. The air conditioning system 1 includes one or a small number of cooling towers 2 installed on the roof of a building 200, for example. The cooling tower 2 supplies circulating water as heat source water to the outdoor units 4 of a plurality of air conditioners installed on each floor of a building, for example, via a circulating water supply pipe 20. Circulating water supplied to the air conditioner 10 via the circulating water supply pipe 20 is used as a heat source in each outdoor unit 4.
In this configuration, each outdoor unit 4 does not include a blower fan such as an outdoor unit that uses air as a heat source, and does not blow out hot or cold air that has undergone heat exchange. For this reason, even if a large number of outdoor units 4 are arranged in close contact with the building as shown in FIG. 1, there are problems that affect the surrounding air temperature by blowing out hot air and cold air, and problems related to exhaust sound. Absent. In addition, since problems such as exhaust shortcuts do not occur at the place where the outdoor unit 4 is installed, the outdoor unit 4 can be installed without problems even in a narrow veranda (balcony).

FIG. 2 is a diagram illustrating a configuration of the air conditioning system 1.
As shown in FIG. 2, the air conditioning system 1 has a configuration in which a plurality of air conditioning apparatuses 10 (four in the example of FIG. 2) are connected to a circulating water supply pipe 20 through which a cooling tower 2 supplies circulating water. It has become. Each air conditioner 10 includes an indoor unit 7 as a use side unit that performs air conditioning in a room to be conditioned, and an outdoor unit 4 as a heat source side unit installed on a veranda or the like. Between the outdoor unit 4 and the indoor unit 7, refrigerant pipes 11 and 12 for circulating the refrigerant and a communication line 13 for transmitting and receiving various control information and the like are arranged.

  The outdoor unit 4 is an engine-driven outdoor unit that drives a compressor 41 (FIG. 3) using a gas engine 42 (FIG. 3) as will be described later. For this reason, the outdoor unit 4 is connected to a gas supply pipe 14 for supplying fuel gas to a gas engine 42 from a building gas piping facility (not shown). Further, the outdoor unit 4 is configured to receive power supply for driving a valve and the like provided in the outdoor unit 4 through the power supply line 15. Furthermore, the outdoor unit 4 is connected to a drain water discharge pipe 16 for draining drain water generated in the heat exchangers provided in the indoor unit 7 and the outdoor unit 4.

  The circulating water supply pipe 20 extending from the cooling tower 2 includes a circulating water feed pipe 20A for sending the circulating water from the cooling tower 2 to the air conditioner 10, and a circulating water return for returning the circulating water from the air conditioner 10 to the cooling tower 2. It is comprised by the pipe | tube 20B. Each air conditioner 10 is connected in parallel to the circulating water feed pipe 20A and the circulating water return pipe 20B, and an open / close valve 23 is arranged on each pipe extending from the circulating water feed pipe 20A to each air conditioner 10. An open / close valve 24 is provided on each pipe connected from each air conditioner 10 to the circulating water return pipe 20B. These on-off valves 23 and 24 are normally opened except when closed to prevent the outflow of circulating water during maintenance of the air conditioner 10, for example.

The cooling tower 2 is a cooling tower that cools the circulating water flowing in the coil by spraying water to a coil (not shown) communicating with the circulating water supply pipe 20. Here, the cooling tower 2 is a hermetic cooling tower, and the circulating water supply pipe 20 and the coil communicating with the circulating water supply pipe 20 constitute a sealed pipe, and the water sprayed on the coil is the circulating water and Is another spray water. For this reason, a foreign material etc. do not mix in the circulating water supplied to the air conditioning apparatus 10 via the circulating water supply pipe 20. FIG. Further, the cooling tower 2 is provided with an antifreezing heater 27 for heating and heating the circulating water circulating through the circulating water supply pipe 20 when it is cold.
A circulating water feed pipe 20A for sending the circulating water from the cooling tower 2 to each air conditioner 10 includes a pump 21 for sending the circulating water cooled in the cooling tower 2 and the circulating water sent from the cooling tower 2. And a flow sensor 22 for detecting the flow state of the gas. Furthermore, the circulating water feed pipe 20A is provided with a circulating water tank 26 for storing extra circulating water. The circulating water tank 26 keeps the circulating water in the circulating water supply pipe 20 at an appropriate amount. Be drunk.

  The cooling tower 2 and each air conditioner 10 are connected to the control device 8 via a control device communication line 81. The control device 8 is a device that controls the overall operation of the circulating water in the air conditioning system 1, and is connected to the pump 21 via a signal line 83 and connected to the flow sensor 22 via a signal line 84. The The circulating water feed pipe 20A is provided with a circulating water temperature sensor 25 for detecting the temperature of the circulating water, and a signal indicating the temperature detected by the circulating water temperature sensor 25 is output to the control device 8 via the signal line 85. Is done.

  The control device 8 transmits and receives various signals between each air conditioner 10 and the cooling tower 2. For example, when receiving a cooling tower operation signal described later from any one of the air conditioners 10, In response, the cooling tower 2 and the pump 21 are operated. Here, when the cooling tower 2 and the pump 21 are already operating, they are operated as they are. And the control apparatus 8 transmits the pump interlock signal which shows that circulating water is supplied to the air conditioning apparatus 10. FIG. The pump interlock signal is generated and output by the control device 8 when the cooling tower 2 and the pump 21 are in operation and the flow sensor 22 detects the flow of circulating water.

  In addition, when the temperature detected by the circulating water temperature sensor 25 is lower than the preset temperature, the control device 8 operates the pump 21 to stop the spraying of the sprayed water in the cooling tower 2, and The freeze prevention heater 27 is operated to prevent the circulating water from freezing. Here, when the detected value of the circulating water temperature sensor 25 remains lower than the set temperature, the control device 8 sends a compulsory interlock signal to the air conditioner 10 to each air conditioner 10. It is also possible to request that the engine be operated.

FIG. 3 is a diagram illustrating a configuration of the air conditioning apparatus 10. FIG. 3 shows the cooling tower 2 for reference. Further, the solid line in the refrigerant flow path of FIG. 3 indicates the flow of the refrigerant during cooling, and the broken line indicates the flow of the refrigerant during heating.
The outdoor unit 4 includes a compressor 41 that compresses the refrigerant and a gas engine 42 that drives the compressor 41, and the gas engine 42 and the compressor 41 are connected via a clutch 43.
The suction pipe and the discharge pipe of the compressor 41 are connected to a four-way valve 50, and one end of an indoor heat exchanger 71 included in the indoor unit 7 is connected to the four-way valve 50 through a refrigerant pipe 12. The other end of the indoor heat exchanger 71 is connected to the receiver tank 53 via the refrigerant pipe 11, and the receiver tank 53 is connected to one end of the outdoor heat exchangers 51 and 52 as heat source side heat exchangers. The other ends of the outdoor heat exchangers 51 and 52 are connected to the four-way valve 50.

  A refrigerant pipe connected to both ends of the outdoor heat exchangers 51 and 52 is provided with a bypass pipe 60 that bypasses the outdoor heat exchangers 51 and 52. One end of the bypass pipe 60 is connected to a branch portion 60A on the refrigerant pipe that connects the receiver tank 53 and the outdoor heat exchanger 51, and the other end of the bypass pipe 60 connects the outdoor heat exchanger 52 and the four-way valve 50. Connected to the branch 60B on the refrigerant pipe. A valve 61 is disposed in the bypass pipe 60, and a valve 62 is disposed between the branch portion 60 </ b> A and the outdoor heat exchanger 51. For this reason, the amount of refrigerant flowing to the bypass pipe 60 and the amount of refrigerant flowing to the outdoor heat exchangers 51 and 52 can be adjusted by adjusting the opening degree of the valves 61 and 62. In the adjustment of the amount of the refrigerant, the ratio of the flow rate of the refrigerant is in the range of 0: 100 to 100: 0, that is, the state in which the entire amount of the refrigerant flows to the bypass pipe 60 and the state in which the entire amount flows to the outdoor heat exchangers 51 and 52. And can be adjusted arbitrarily.

  The outdoor heat exchangers 51 and 52 are two heat exchangers connected in series, and the refrigerant flowing into the outdoor heat exchanger 51 from the receiver tank 53 flows through the outdoor heat exchanger 52 to the four-way valve 50, The refrigerant flowing into the outdoor heat exchanger 52 flows into the receiver tank 53 through the outdoor heat exchanger 51. The outdoor heat exchangers 51 and 52 are connected to the circulating water supply pipe 63 in parallel, and are water heat exchangers that perform heat exchange between the circulating water supplied from the circulating water supply pipe 63 and the refrigerant. For example, it is configured as a plate heat exchanger.

Specifically, the circulating water supply pipe 63 connected to the circulating water feed pipe 20 </ b> A extending from the cooling tower 2 has a circulating water circuit for flowing the circulating water to the outdoor heat exchanger 51 and the circulating water to the outdoor heat exchanger 52. Branching to the circulating water circuit, the circulating water having the same water temperature is supplied to the two outdoor heat exchangers 51 and 52. On the other hand, the outdoor heat exchangers 51 and 52 are connected in series in the refrigerant circuit, and the refrigerant flows through the outdoor heat exchangers 51 and 52 in order. For this reason, the refrigerant is heat-exchanged with circulating water having sufficient heat or cold in each of the outdoor heat exchangers 51 and 52. The circulating water that has passed through the outdoor heat exchangers 51 and 52 merges, flows through the circulating water supply pipe 64, and returns to the cooling tower 2 from the circulating water return pipe 20B.
Each of the circulating water supply pipes 63 and 64 is provided with water temperature sensors 68 and 69 for detecting the temperature of the circulating water, and the temperature of the circulating water supplied from the circulating water feed pipe 20A and the circulating water return pipe. The temperature of the circulating water returned to 20B can be detected.

An expansion valve 56 for reducing the pressure of the refrigerant is disposed between the receiver tank 53 and the branch portion 60A, and a gas refrigerant and a liquid refrigerant are provided between the four-way valve 50 and the suction pipe of the outdoor heat exchanger 51. An accumulator 54 that separates and prevents liquid back is connected.
During the cooling operation of the air conditioner 10, the refrigerant discharged from the compressor 41 flows to the outdoor heat exchanger 52 via the four-way valve 50, as indicated by a solid line in FIG. 52 functions as a condenser, becomes a liquid refrigerant, passes through the expansion valve 56, and flows to the indoor heat exchanger 71 through the refrigerant pipe 11. Here, the indoor heat exchanger 71 functions as an evaporator, and the refrigerant evaporated in the indoor heat exchanger 71 returns to the outdoor unit 4 through the refrigerant pipe 12 and is sucked into the compressor 41 from the four-way valve 50 through the accumulator 54. It is.

On the other hand, during the heating operation of the air conditioner 10, the refrigerant discharged from the compressor 41 flows from the refrigerant pipe 12 to the indoor heat exchanger 71 via the four-way valve 50, as indicated by a broken line in FIG. It is condensed in the heat exchanger 71 and returns to the outdoor unit 4 through the refrigerant pipe 11. The refrigerant returned to the outdoor unit 4 is decompressed by the expansion valve 56 and flows to the outdoor heat exchangers 51 and 52. The outdoor heat exchangers 51 and 52 function as an evaporator to become a gas refrigerant, and the four-way valve 50 To the compressor 41 through the accumulator 54.
Pressure sensors 41 </ b> A and 41 </ b> B are disposed on the discharge pipe and the suction pipe of the compressor 41, respectively. The pressure sensor 41A detects the high-pressure side refrigerant pressure in the refrigerant circuit of the air conditioner 10, and the pressure sensor 41B detects the low-pressure side refrigerant pressure. The detected pressure values detected by the pressure sensors 41A and 41B are acquired by the microcomputer 40A of the electrical unit 40 described later.

The outdoor unit 4 includes an engine coolant circuit 44 that cools the gas engine 42 with engine coolant. The engine coolant circuit 44 includes a coolant pump 45 that sends engine coolant to the gas engine 42, a radiator 48 that exchanges heat between the circulating water flowing through the circulating water supply pipe 64 and the engine cooling water, and engine cooling water. An auxiliary heat exchanger 49 that exchanges heat with the refrigerant, and a proportional three-way valve 46 and 47 that distributes engine cooling water to the radiator 48 and the auxiliary heat exchanger 49 are provided.
The engine coolant circuit 44 is provided with a coolant temperature sensor (not shown) that detects the temperature of the engine coolant.

The radiator 48 is a heat exchanger that radiates engine cooling water by circulating water flowing through the circulating water supply pipe 64. The radiator 48 is located on the downstream side of the outdoor heat exchangers 51 and 52, and is supplied with circulating water after heat exchange is performed in the outdoor heat exchangers 51 and 52. This is because, for example, when cooling operation, flowing low-temperature circulating water to the outdoor heat exchangers 51 and 52 can exhibit higher cooling capacity, and engine cooling water that has passed through the gas engine 42 has passed through the outdoor heat exchangers 51 and 52. Since the temperature is sufficiently higher than the circulating water after, the radiator 48 can reliably radiate the engine cooling water even if the circulating water whose temperature has been increased by the outdoor heat exchangers 51 and 52 is used. Therefore, it is a rational and useful configuration.
3 shows a configuration in which a part of the circulating water flows to the radiator 48 by a pipe branched from the circulating water supply pipe 64. However, a configuration in which the entire circulating water flows through the radiator 48 may be used. What is necessary is just to determine suitably the quantity of the circulating water which flows through 48 according to the size of the radiator 48, the required heat dissipation capability, etc. FIG.

  The auxiliary heat exchanger 49 is a heat exchanger that gives heat of the engine cooling water to the refrigerant that returns to the suction pipe of the compressor 41 in the refrigerant circuit. The auxiliary heat exchanger 49 is a water heat exchanger that exchanges heat between the refrigerant and water, like the outdoor heat exchangers 51 and 52, and is configured as, for example, a plate heat exchanger.

  In the engine coolant circuit 44, the engine coolant discharged from the gas engine 42 is circulated through the auxiliary heat exchanger 49, the conduit circulated through the radiator 48, and the coolant pump 45. Returning pipe lines are provided, and two proportional three-way valves 46 and 47 are provided to control the circulation amount of the engine cooling water to these pipe lines. The proportional three-way valves 46 and 47 are valves that distribute the engine coolant flowing in from one side in the other two directions, and the distribution ratio can be changed in the range of 0: 100 to 100: 0.

  The proportional three-way valve 47 distributes the engine cooling water that has exited the gas engine 42 into a pipe line that returns to the cooling water pump 45 and a pipe line that flows to the radiator 48 or the auxiliary heat exchanger 49. For example, immediately after the gas engine 42 is started, the engine cooling water is usually very low in temperature. If the engine cooling water temperature is low, the viscosity of the engine oil of the gas engine 42 becomes high. Therefore, when the engine cooling water is at a low temperature, the temperature of the engine cooling water needs to be quickly raised by the exhaust heat of the gas engine 42. There is. In such a case, the proportional three-way valve 47 distributes the whole or most of the engine cooling water discharged from the gas engine 42 to a pipe line that returns to the cooling water pump 45. As a result, the engine coolant circulates only between the gas engine 42 and the coolant pump 45, so that the engine coolant is immediately warmed by the exhaust heat of the gas engine 42. When the temperature of the engine cooling water becomes equal to or higher than a predetermined temperature, the proportional three-way valve 47 distributes the engine cooling water to the pipes that flow to the radiator 48 and the auxiliary heat exchanger 49.

  The proportional three-way valve 46 distributes the engine cooling water distributed by the proportional three-way valve 47 into a pipe line going to the radiator 48 and a pipe line going to the auxiliary heat exchanger 49. For example, when the air-conditioning apparatus 10 is in the cooling operation, it is not necessary to apply heat to the refrigerant in the auxiliary heat exchanger 49, and therefore the proportional three-way valve 46 is configured to supply all of the engine cooling water sent from the proportional three-way valve 47 to the radiator. 48. Further, the proportional three-way valve 46 gives heat to the refrigerant during the heating operation of the air conditioner 10, so that the heating load, the pressure difference between the high pressure side and the low pressure side of the refrigerant, the temperature of the circulating water flowing through the circulating water supply pipe 63, etc. The required amount of engine coolant is distributed to the auxiliary heat exchanger 49 based on the above.

  As shown in FIG. 3, the engine coolant circuit 44 is configured such that the radiator 48 and the auxiliary heat exchanger 49 are both connected to the proportional three-way valve 46 and the engine coolant flows in parallel. Since both the radiator 48 and the auxiliary heat exchanger 49 have the effect of dissipating the heat of the engine cooling water, the configuration in which the engine cooling water flows in parallel as shown in FIG. It is reasonable and useful.

  The outdoor unit 4 is provided with an electrical unit 40 that incorporates a power supply circuit that supplies power to each part of the air conditioner 10, a control circuit that includes a microcomputer 40A that controls each part of the air conditioner 10, and the like. . The microcomputer 40A controls each part of the air conditioning apparatus 10 and functions as a control part that transmits and receives various signals to and from the control apparatus 8 (FIG. 2) via the control apparatus communication line 81.

  The microcomputer 40A is configured such that the circulating water temperature detected by the water temperature sensors 68 and 69, the engine cooling water temperature detected by the cooling water temperature sensor (not shown), and the high-pressure side refrigerant detected by the pressure sensors 41A and 41B. Values such as the pressure and the refrigerant pressure on the low pressure side, the temperature in the conditioned room in the indoor unit 7, the temperature of the indoor heat exchanger 71, and the like are acquired. Then, based on the acquired value, the microcomputer 40A controls the operation of the compressor 41 by starting / stopping the gas engine 42 included in the outdoor unit 4, the disconnection / connection control of the clutch 43, the switching control of the four-way valve 50, the expansion valve. 56, opening / closing and opening control of the valves 61, 62, operation / stop control of the cooling water pump 45, distribution control by the proportional three-way valves 46, 47, and the like.

When the microcomputer 40A is instructed to start or stop the cooling operation or the heating operation by the remote control device 70 provided in the indoor unit 7, the microcomputer 40A sets the set values such as the target temperature set by the operation of the remote control device 70 and the above-described various types. Based on the value acquired from a sensor etc., the driving | running state of the air conditioning apparatus 10 is controlled.
Then, when driving the compressor 41 (thermo-on), the microcomputer 40A transmits a cooling tower operation signal to the control device 8 via the control device communication line 81, and responds to this cooling tower operation signal to the control device 8 When the pump interlock signal transmitted from is received, the gas engine 42 is started and the clutch 43 is connected to operate the compressor 41.

In the air-conditioning apparatus 10 configured as described above, when performing a cooling operation, the refrigerant compressed by the compressor 41 as described above passes through the four-way valve 50 under the control of the microcomputer 40A and performs outdoor heat exchange as a condenser. The refrigerant flows into the vessels 51 and 52, is condensed, decompressed by the expansion valve 56, and sent to the indoor heat exchanger 71 through the refrigerant pipe 11. The indoor heat exchanger 71 functions as an evaporator, and cools the conditioned room in which the indoor unit 7 is installed by evaporating the refrigerant. The refrigerant evaporated in the indoor heat exchanger 71 returns to the outdoor unit 4 through the refrigerant pipe 12 and reaches the suction pipe of the compressor 41 through the four-way valve 50.
Here, when the temperature of the circulating water supplied from the cooling tower 2 is low, the refrigerant condensing temperature in the outdoor heat exchangers 51 and 52 becomes lower than an appropriate range. For this reason, there is a possibility that the refrigerant is not sufficiently evaporated in the indoor heat exchanger 71, which is not preferable.

Therefore, the microcomputer 40A acquires the high-pressure side refrigerant pressure detected by the pressure sensor 41A and the low-pressure side refrigerant pressure detected by the pressure sensor 41B, and obtains a pressure difference between the high-pressure side and the low-pressure side. A decrease in the refrigerant condensing temperature in the refrigerant circuit causes a reduction in the pressure difference between the high pressure side and the low pressure side. In other words, when the pressure difference between the high-pressure side and the low-pressure side is reduced, the cause is that the circulating water has a low temperature, which causes a decrease in the refrigerant condensing temperature. Therefore, the microcomputer 40A adjusts the openings of the valves 61 and 62 when the pressure difference between the high-pressure side and the low-pressure side falls below a preset pressure difference, and sets the refrigerant discharged from the compressor 41. Part or all is passed through the bypass pipe 60 without flowing through the outdoor heat exchangers 51 and 52. Here, the set pressure difference is set at the time of shipment or installation of the air conditioner 10, and is stored in the microcomputer 40A.
Thereby, at least a part of the refrigerant reaches the expansion valve 56 without exchanging heat with the low-temperature circulating water in the outdoor heat exchangers 51 and 52, so that the temperature of the refrigerant flowing from the expansion valve 56 to 71 is kept in a favorable range. Can do.
By the above control, when the circulating water becomes lower than a predetermined temperature during the heating operation, an excessive decrease in the refrigerant condensing temperature can be prevented, and a stable cooling operation can be realized.

FIG. 4 is a flowchart showing the operation of the air conditioning apparatus 10 described above, and particularly shows the operation when the thermo-ON is performed during the cooling operation.
When the cooling operation is started or when the thermostat is turned on, the microcomputer 40A transmits a cooling tower operation signal to the control device 8 via the control device communication line 81 (step S11). Here, the microcomputer 40A waits until it receives the pump interlock signal from the control device 8 (step S12). When the microcomputer 40A receives the pump interlock signal (step S12: Yes), it starts the gas engine 42 and activates the clutch 43. The connected state is set (step S13). Thereby, the compressor 41 starts operation.

Subsequently, the microcomputer 40A acquires the detected value of the refrigerant pressure detected by each of the pressure sensors 41A and 41B (step S14), and the high pressure side refrigerant pressure detected by the pressure sensor 41A and the low pressure detected by the pressure sensor 41B. The pressure difference with the refrigerant pressure on the side is obtained, and the flow rate of the refrigerant to the bypass pipe 60 is adjusted based on this pressure difference (step S15). Here, the microcomputer 40A causes the valves 61 and 62 to function as a proportional valve based on the pressure difference, and finely adjusts the ratio of the refrigerant flowing through the bypass pipe 60 and the outdoor heat exchangers 51 and 52.
Specifically, when the pressure difference between the high pressure side and the low pressure side is less than 0.5 to 0.6 MPa (megapascal), the microcomputer 40A sets the ratio of the refrigerant flowing through the bypass pipe 60 to be greater than zero. For example, 50% or more, or 100%.
The microcomputer 40A adjusts the flow rate of the refrigerant to the bypass pipe 60 in consideration of the detection value of the water temperature sensor 68, the temperature of the engine cooling water, etc. in addition to the detection values of the pressure sensors 41A and 41B. Good.

  Thereafter, the microcomputer 40A determines whether or not to switch to thermo-off (step S16). If the thermo-on state is continued (step S16: No), the process returns to step S11. In addition, for example, when switching to thermo-off (eg, when the temperature of the conditioned room reaches a set temperature) (step S16: Yes), the microcomputer 40A stops the gas engine 42 (step S17), and further with the stop of the gas engine 42 The various valves of the outdoor unit 4 are controlled to be in an initial state or a standby state (step S18), and the operation ends.

  As described above, according to the air conditioning system 1 according to the embodiment to which the present invention is applied, the circulating water is supplied from the cooling tower 2 to the plurality of air conditioning apparatuses 10, and the air conditioning apparatus 10 is supplied from the cooling tower 2. Outdoor heat exchangers 51 and 52 for exchanging heat between the circulating water and the refrigerant are provided. Then, when the difference in refrigerant pressure between the high pressure side and the low pressure side in the refrigerant piping of the air conditioner 10 falls below a preset value, such as when the circulating water is at a low temperature during the cooling operation, the control of the microcomputer 40A Thus, the refrigerant flows from the expansion valve 56 to the indoor heat exchanger 71 through the bypass pipe 60 without passing through the outdoor heat exchangers 51 and 52. As a result, an excessive decrease in the refrigerant condensing temperature can be prevented, the already lowered refrigerant temperature can be recovered to a suitable temperature, the refrigerant can be sufficiently evaporated in the indoor heat exchanger 71, and a stable cooling operation can be performed. realizable.

  Moreover, even if it does not change the supply state of the circulating water by the cooling tower 2, the air conditioning apparatus 10 which performs cooling operation controls its own operation | movement, and can implement | achieve stable cooling operation. Therefore, for example, even in a state where a plurality or most of the plurality of air conditioners 10 connected to the cooling tower 2 perform a heating operation and only some of the air conditioners 10 perform a cooling operation in the cold season, Without affecting the operation of the air conditioner 10 or the cooling tower 2 that is operating, the air conditioner 10 that performs the cooling operation can avoid an excessive decrease in the refrigerant condensing temperature and can perform the cooling operation stably.

  Furthermore, when the difference between the refrigerant pressure on the discharge side detected by the pressure sensor 41A and the refrigerant pressure on the suction side detected by the pressure sensor 41B falls below a preset pressure difference, the microcomputer 40A compresses the compressor 41. Control is performed so that a part or all of the refrigerant discharged from the refrigerant flows through the bypass pipe 60 without flowing through the outdoor heat exchangers 51 and 52. Accordingly, it is possible to quickly cope with a situation where the refrigerant condensing temperature tends to be excessively lowered, to avoid further reduction of the refrigerant condensing temperature, and to quickly recover the refrigerant condensing temperature to a suitable temperature. .

  Furthermore, the microcomputer 40A controls the valves 61 and 62 to control the outdoor heat exchanger 51 based on the difference between the refrigerant pressure on the discharge side detected by the pressure sensor 41A and the refrigerant pressure on the suction side detected by the pressure sensor 41B. , 52 and the bypass pipe 60 are set with a ratio of distributing the refrigerant. By finely adjusting the flow of the refrigerant, the influence of the circulating water temperature being too low can be recovered and a stable cooling operation can be realized.

  In the above embodiment, the valves 61 and 62 are both valves whose opening degree can be adjusted, and these two valves are integrated to function as a proportional valve. However, the present invention is not limited to this. For example, the refrigerant returning to the suction pipe of the compressor 41 via the expansion valve 56 may be selectively flowed only to one of the outdoor heat exchangers 51 and 52 and the bypass pipe 60. In this case, the cost can be reduced while maintaining a configuration that can prevent freezing of the circulating water in the outdoor heat exchangers 51 and 52.

The microcomputer 40A has been described as adjusting the amount of refrigerant flowing through the bypass pipe 60 based on the difference in refrigerant pressure detected by the pressure sensors 41A and 41B (step S15 in FIG. 3). For example, the temperature of the refrigerant in the indoor heat exchanger 71 itself may be measured, and adjustment may be performed in consideration of the measured temperature of the indoor heat exchanger 71.
Furthermore, in the said embodiment, as the indoor unit 7 of the air conditioning apparatus 10, various types of air conditioning apparatuses of a wall hanging type, a ceiling embedded type, and a ceiling suspended type are applicable. The number of air conditioners 10 connected to one cooling tower 2 via the circulating water supply pipe 20 is also arbitrary, and other detailed configurations of the air conditioner 10 and the air conditioner system 1 are described in the present invention. Any change can be made without departing from the spirit of the invention.

It is a figure which shows the example of the installation state of the air conditioning system which concerns on embodiment of this invention. It is a figure which shows schematic structure of an air conditioning system. It is a figure which shows the structure of an air conditioning apparatus. It is a flowchart which shows operation | movement of an air conditioning apparatus.

Explanation of symbols

1 Air conditioning system 2 Cooling tower 4 Outdoor unit (heat source side unit)
DESCRIPTION OF SYMBOLS 7 Indoor unit 8 Control apparatus 10 Air conditioning apparatus 11, 12 Refrigerant piping 13 Communication line 20 Circulating water supply pipe 21 Pump 22 Flow sensor 25 Circulating water temperature sensor 27 Antifreeze heater 40 Electrical unit 40A Microcomputer (control part)
41 Compressor 41A, 41B Pressure sensor 42 Gas engine 43 Clutch 44 Engine cooling water circuit 45 Cooling water pump 46, 47 Proportional three-way valve 48 Radiator 49 Auxiliary heat exchanger 50 Four-way valve 51, 52 Outdoor heat exchanger (heat source side heat exchange) vessel)
53 Receiver tank 54 Accumulator 56 Expansion valve 60 Bypass pipe 61, 62 Valve 63, 64 Circulating water supply pipe 68, 69 Water temperature sensor 70 Remote control device 71 Indoor heat exchanger 81 Controller communication line 82, 83, 84, 85 Signal line

Claims (5)

In the heat source side unit of the air conditioner, comprising: a compressor that compresses the refrigerant; and a heat source side heat exchanger that exchanges heat between the externally supplied water and the refrigerant.
Providing a bypass pipe for bypassing the heat source side heat exchanger;
When the refrigerant pressure difference between the discharge side and the suction side of the compressor is small during the cooling operation, a part or all of the refrigerant discharged from the compressor does not flow to the heat source side heat exchanger and the bypass pipe Equipped with a control unit that controls to flow through
A heat source side unit characterized by When the difference between the refrigerant pressure in the refrigerant line connected to the discharge side of the compressor and the refrigerant pressure in the refrigerant line connected to the suction side of the compressor is less than a preset pressure difference, the control unit In addition, control is performed so that part or all of the refrigerant discharged from the compressor flows through the bypass pipe without flowing through the heat source side heat exchanger,
The heat source unit according to claim 1. A valve for distributing refrigerant to the heat source side heat exchanger and the bypass pipe;
The control unit sets a ratio of distributing the refrigerant to the heat source side heat exchanger and the bypass pipe by the valve based on a difference in refrigerant pressure between the discharge side and the suction side of the compressor during the cooling operation. Doing control,
The heat source side unit according to claim 1 or 2. In an air conditioner including a heat source side unit including a compressor that compresses a refrigerant, and a heat source side heat exchanger that exchanges heat between water supplied from the outside and the refrigerant,
The heat source side unit is provided with a bypass pipe that bypasses the heat source side heat exchanger, and when the difference in refrigerant pressure between the discharge side and the suction side of the compressor is small during cooling operation, A control unit that performs control so that a part or all of the discharged refrigerant flows through the bypass pipe without flowing through the heat source side heat exchanger;
An air conditioner characterized by. A plurality of air conditioners including a heat source side unit including a compressor that compresses refrigerant and a heat source side heat exchanger that exchanges heat between the heat source water and the refrigerant are connected to a heat source water supply unit that supplies heat source water. Configured
In the heat source side unit of the air conditioner,
Providing a bypass pipe for bypassing the heat source side heat exchanger;
When the refrigerant pressure difference between the discharge side and the suction side of the compressor is small during the cooling operation, a part or all of the refrigerant discharged from the compressor does not flow to the heat source side heat exchanger and the bypass pipe Equipped with a control unit that controls to flow through
Air conditioning system characterized by

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