JP4145632B2 - Annual cooling type air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioner for a high heat generating device that requires cooling even when the outside air temperature is low. Specifically, when the outside air temperature is high, cooling is performed by a compression-type cooling cycle, and when the outside air temperature is low. The present invention relates to an annual cooling type air conditioner that actively cools an indoor air temperature.
[0002]
[Prior art]
In this type of annual cooling type air conditioner, when the outside air temperature is high, cooling using a compression type cooling cycle is performed. That is, the gas refrigerant is pressurized by the compressor and sent to the condenser as a high-temperature and high-pressure gas, and the refrigerant liquefies by exchanging heat with the outside air. The liquid refrigerant is decompressed by the expansion valve, reaches the evaporator, and the refrigerant is gasified by cooling the indoor air in the evaporator and returns to the compressor. Hereinafter, by repeating this cycle, the indoor heat is released into the atmosphere through the evaporator and the condenser to cool the room.
[0003]
On the other hand, when the outside air temperature is low, the cooling operation is performed only by circulating the refrigerant by the refrigerant pressure feeding means without operating the compressor. Cooling by this method is called indirect external unit cooling because the refrigerant is once cooled by the outside air and the room is cooled by the cooled refrigerant. Although water may be used as the circulation medium, phase change can be used by using a refrigerant, and the power of the pumping means can be reduced by reducing the circulation amount. The cooling cycle in indirect outside air cooling will be described below.
[0004]
The gas refrigerant exiting the evaporator is sent to the condenser as it is, cooled in the condenser by the low temperature outside air, liquefied, and sent to the refrigerant pressure sending means. The liquid refrigerant is pressurized by the refrigerant pressure feeding means and guided to the evaporator. In the evaporator, the indoor air is cooled to gasify the refrigerant and return to the condenser again. Thereafter, this cycle is repeated to cool the room by releasing the heat of the room into the atmosphere through the evaporator and the condenser.
[0005]
In general, when the outside air temperature is high, the operation is performed in the compression cycle described first, and when the outside air temperature is low, the operation is performed in the indirect outside air cooling cycle described above. The cycle switching timing is determined by the outside air temperature, the outside air temperature and the cooling capacity, or the set value of the outside air temperature and the compressor frequency. Note that Patent Documents 1 to 3 are known as documents disclosing such conventional annual cooling type air conditioners.
[0006]
[Patent Document 1]
JP-A-10-82566 [Patent Document 2]
JP 2000-193327 A [Patent Document 3]
JP 2001-248925 A
[Problems to be solved by the invention]
By the way, during the cooling operation in the indirect outdoor air cooling cycle, when the indoor / outdoor temperature difference is not sufficient, the refrigerant is not liquefied in the condenser, so the refrigerant vaporizes in front of or inside the refrigerant pumping means, and cavitation occurs. May occur. Also, even when the condenser capacity increases rapidly, the pressure is instantaneously transmitted to the entire refrigerant circulation system, whereas the temperature is sequentially transmitted by the refrigerant circulation, so that the refrigerant saturates in the refrigerant pumping means due to this time difference. Vaporization may cause cavitation. Here, cavitation is a phenomenon in which a gas is generated in a flowing liquid to create a cavity.
[0008]
When cavitation occurs, the refrigerant is in a gas-liquid mixed state and the circulation rate is reduced or becomes very unstable. As a result, in the indirect outdoor air cooling cycle, sufficient cooling capacity cannot be exhibited. Furthermore, there is a risk of destroying the refrigerant pumping means due to pressure fluctuations due to cavitation and poor wetting.
[0009]
The present invention has been made in consideration of such circumstances, and an object thereof is to provide an annual cooling type air conditioner capable of preventing the occurrence of cavitation.
[0010]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 is configured such that a compressor, a condenser provided outdoors, an expansion valve, and an evaporator provided indoors are connected by piping. A vapor compression cooling circuit that circulates the refrigerant, an outdoor fan that sends air to the condenser, an indoor fan that sends air to the evaporator, and a pipe between the condenser and the expansion valve. The refrigerant pressure feeding means, the refrigerant pressure feeding means is inoperative, the cooling function by a vapor compression type cooling cycle for cooling the room with the compressor in an operating state, the refrigerant pressure feeding means is operated, and the compressor is Measures the flow rate of the liquid refrigerant sent from the refrigerant pumping means during operation by the indirect outside air cooling cycle in an annual cooling type air conditioner having a cooling function by an indirect outside air cooling cycle that cools the room as an inoperative state That the refrigerant flow rate measuring means, when the measurement result of the refrigerant flow rate measuring means during the operation by the indirect outdoor air cooling cycle is below a preset constant value, the input amount of the refrigerant pumping means, the indoor blower Control means for controlling at least one of an air volume, an air volume of the outdoor blower, and a valve opening degree of the expansion valve, wherein the control means has a measurement result of the refrigerant flow rate measuring means equal to or less than a predetermined value set in advance. When the number of times exceeds the predetermined number within a predetermined time, the cooling cycle is changed from the indirect outside air cooling cycle to the vapor compression cooling cycle .
[0011]
According to a second aspect of the present invention, there is provided a compressor, a condenser provided outside the room, an expansion valve, a vapor compression cooling circuit that circulates a refrigerant by connecting an evaporator provided inside the pipe, and the condenser. An outdoor blower for sending wind, an indoor blower for sending wind to the evaporator, and a refrigerant pressure feeding means provided in a pipe between the condenser and the expansion valve, and the refrigerant pressure feeding means is inoperative , A cooling function by a vapor compression cooling cycle that cools the room with the compressor in an operating state, and a cooling function by an indirect outside air cooling cycle that operates the refrigerant pressure feeding unit and cools the room with the compressor inoperative in annual cooling-type air conditioner having bets, and the liquid level detecting means for detecting the height of the liquid level of the liquid refrigerant outputted from the condenser during operation by the indirect outdoor air cooling cycle, luck by the indirect outdoor air cooling cycle When the detection result of the liquid level sensing means is below a preset constant value in the middle, the input amount of the refrigerant pumping means, the air volume of the indoor blower, the air volume of the chamber outer blower valve of the expansion valve Control means for controlling at least one of the opening degrees, the control means , when a state in which the detection result of the liquid level detection means has become a predetermined value or less has been continued for a predetermined time or more, cooling cycle Is changed from the indirect outdoor air cooling cycle to the vapor compression type cooling cycle .
[0012]
The invention described in claim 3 includes a compressor, a condenser provided outside the room, an expansion valve, a vapor compression cooling circuit that circulates a refrigerant by connecting an evaporator provided inside the pipe, and the condenser. An outdoor blower for sending wind, an indoor blower for sending wind to the evaporator, and a refrigerant pressure feeding means provided in a pipe between the condenser and the expansion valve, and the refrigerant pressure feeding means is inoperative , A cooling function by a vapor compression cooling cycle that cools the room with the compressor in an operating state, and a cooling function by an indirect outside air cooling cycle that operates the refrigerant pressure feeding unit and cools the room with the compressor inoperative in annual cooling-type air conditioner having bets, and the temperature sensing means and pressure sensing means for detecting respectively the temperature and pressure of the liquid refrigerant outputted from the condenser during operation by the indirect outdoor air cooling cycle, the inter When supercooling degree which is calculated based on the output of the output and the pressure detecting means of said temperature detecting means during the operation by the outdoor air cooling cycle is below a preset constant value, the input amount of the refrigerant pumping means, said The control means for controlling at least one of the air volume of the indoor fan, the air volume of the outdoor fan, and the opening degree of the expansion valve, and the control means has the supercooling degree equal to or less than a predetermined value set in advance. When the state has continued for a predetermined time or longer, the cooling cycle is changed from the indirect outside air cooling cycle to the vapor compression cooling cycle .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing the configuration of an annual cooling type air conditioner according to the first embodiment of the present invention. The annual cooling type air conditioner shown in this figure mainly includes an evaporator (indoor heat exchanger) 1, an indoor fan 2, an outdoor fan air volume control device 3, an indoor temperature sensor 4, a compressor 5, and an inverter for the compressor. 6, compressor bypass valve 7, condenser (outdoor heat exchanger) 8, outdoor blower 9, outdoor blower air volume control device 10, refrigerant pressure feeding means 11, refrigerant pressure feeding means control device 12, refrigerant pressure feeding means bypass valve 13 , An outside air temperature sensor 14, a refrigerant flow rate detection means 15, an expansion valve 16, an expansion valve control device 17, an expansion valve bypass valve 18, and a calculation unit 19.
[0017]
When operating in the compression cycle, the refrigerant pressure feeding means bypass valve 13 is opened, and the compressor bypass valve 7 and the expansion valve bypass valve 18 are closed. The compression cycle operates as follows. The gas refrigerant is pressurized by the compressor 5 and sent to the condenser 8 as a high-temperature and high-pressure gas. The condenser 8 exchanges heat with the outside air and liquefies the refrigerant. The liquid refrigerant is decompressed by the expansion valve 16 and reaches the evaporator 1, and the refrigerant is gasified by cooling the indoor air in the evaporator 1, and returns to the compressor 5. Hereinafter, by repeating this cycle, indoor heat is released by releasing indoor heat into the atmosphere via the evaporator 1 and the condenser 8.
[0018]
On the other hand, when operating by an indirect outside air cooling cycle, the refrigerant pressure feed unit bypass valve 13 is closed, and the compressor bypass valve 7 and the expansion valve bypass valve 18 are opened. The indirect outdoor air cooling cycle operates as follows. The gas refrigerant exiting the evaporator 1 is sent to the condenser 8 as it is, cooled in the condenser 8 with low temperature outside air, liquefied, and sent to the refrigerant pressure sending means 11. The liquid refrigerant is pressurized by the refrigerant pressure feeding means 11 and guided to the evaporator 1. In the evaporator 1, the refrigerant is gasified by cooling the indoor air and returns to the condenser 8 again. Thereafter, this cycle is repeated, and indoor heat is released by releasing indoor heat into the atmosphere via the evaporator 1 and the condenser 8.
[0019]
An example of the refrigerant pumping means 11 is a device that applies pressure and speed to the liquid by mechanical energy, a so-called mechanical pump, or the like, but any means that can pump the refrigerant can be used. For example, a heat pump or the like may be used. Further, the refrigerant pressure feeding means bypass valve 13 may be a check valve instead of the solenoid valve, but in this case, the valve opening / closing operation is not required. Further, the refrigerant flow rate detection means 15 may be a flow switch in which a threshold value is set instead of a flow meter.
[0020]
Next, the cavitation prevention operation performed in the above embodiment will be described. FIG. 2 is a flowchart showing the cavitation prevention operation. First, during the indirect outdoor air cooling cycle operation (step Sa1), the refrigerant circulation amount is constantly detected by the refrigerant flow rate detection means 15 (step Sa2). As a result of the detection, if the state equal to or lower than the set flow rate A continues for T1 hours or more (determination in step Sa2 is YES), it is determined that cavitation is just occurring and “1” is added to the counter (step Sa3). Next, the input of the refrigerant pressure feeding means 11 is set to 0, the refrigerant pressure feeding means 11 is stopped, and then the indoor / outdoor blowers 2 and 9 are set to the maximum air volume. And after predetermined time T2 progress, the refrigerant | coolant pressure sending means 11 is started again (step Sa5). Then, the process returns to step Sa2.
[0021]
Again, during the indirect outside air cooling cycle operation, if it is determined in step Sa2 that the cavitation has just occurred, and the detection immediately before the occurrence of cavitation has reached a predetermined number of times B during the predetermined time T3 (determination in step Sa4). Is YES), the input of the refrigerant pressure sending means 11 is stopped as 0, and the process proceeds to the compression cycle (step Sa6). After the passage of the predetermined time T4 in the compression cycle, when the indoor / outdoor temperature difference is equal to or smaller than the set value C (NO at Step Sa7), the compressor 5 is continuously operated (Step Sa8) and is larger than the set value C. If this is the case (YES at step Sa7), the detection counter immediately before the occurrence of cavitation is reset, and the indirect outside air cooling cycle operation is performed again (step Sa9).
[0022]
Next explained is the second embodiment of the invention. FIG. 3 is a schematic configuration diagram showing the configuration of the annual cooling type air conditioner according to the embodiment. The annual cooling type air conditioner shown in this figure is different from that shown in FIG. The liquid level detecting means 21 for detecting the liquid level height is installed between the condenser 8 and the refrigerant pressure sending means 11. FIG. 3 shows an example in which the liquid tank 22 exists between the condenser 8 and the refrigerant pressure sending means 11, but the liquid level detection means 21 works effectively even when it does not exist.
[0023]
Hereinafter, the cavitation prevention operation in this embodiment will be described with reference to the flowchart shown in FIG. First, during the indirect outdoor air cooling cycle operation (step Sb1), the coolant level is constantly detected by the level detection means 21. As a result of the detection, if the flow rate is equal to or lower than the set flow rate D (NO in step Sb2), it is determined that cavitation has just occurred, the input of the refrigerant pressure sending means 11 is set to 0, and the air volume of the indoor / outdoor fans 2 and 9 is maximized ( Step Sb3). In this state, the liquid level height is constantly detected by the liquid level detecting means 21. As a result of the detection, if a liquid level equal to or higher than the liquid level D + E is secured, the refrigerant pressure feeding means 11 is activated again (step Sb5). If the D + E liquid level cannot be secured by the liquid level detection means 21 even after the time T5 has elapsed (YES in step Sb6), the process proceeds to the compression cycle. After the predetermined time T6 has elapsed (step Sb7), when the indoor / outdoor temperature difference is equal to or smaller than the set value F (NO in step Sb8), the compressor 5 is continuously operated (step Sb9). When the temperature difference is larger than the set value F (Yes in step Sb8), the indirect outside air cooling cycle operation is performed again (step Sb1).
[0024]
Next explained is the third embodiment of the invention. FIG. 5 is a schematic configuration diagram showing the configuration of the annual cooling type air conditioner according to the embodiment. The annual cooling type air conditioner shown in this figure is different from that shown in FIG. The refrigerant temperature detecting means 24 and the refrigerant pressure detecting means 25 are installed between the condenser 8 and the refrigerant pressure sending means 11.
[0025]
Hereinafter, the cavitation prevention operation in this embodiment will be described with reference to the flowchart shown in FIG. First, during the indirect outdoor air cooling cycle operation (step Sc1), the temperature and pressure of the refrigerant immediately before the refrigerant pressure feeding means 11 are constantly detected by the detection means 24 and 25, and are input to the calculation unit 19 to calculate the degree of supercooling. Here, the degree of supercooling is calculated as the difference between the saturation temperature of the liquid refrigerant determined based on the pressure detected by the pressure detection means 25 and the temperature measured by the temperature detection means 24. When the calculated degree of subcooling of the refrigerant before the refrigerant pressure sending means 11 is equal to or lower than the set supercooling degree G (NO in Step Sc2), it is judged that the cavitation has just occurred, and the refrigerant pressure sending means 11 is input. Is set to 0, and the air volumes of the indoor and outdoor fans 2 and 9 are maximized (step Sc3).
[0026]
In this state, the refrigerant supercooling degree immediately before the refrigerant pressure feeding means 11 is detected based on the outputs of the temperature detecting means 24 and the pressure detecting means 25. As a result, the refrigerant subcooling degree before the refrigerant pressure feeding means 11 is set as the set supercooling degree. If it is determined that the value is larger than G + H (YES in step Sc4), the refrigerant pressure feeding means 11 is activated again (step Sc5). If it is not determined that the refrigerant supercooling degree before the refrigerant pressure sending means 11 is greater than the set supercooling degree G + H even after the time T7 has elapsed (YES in step Sc6), the process proceeds to the compression cycle. After the predetermined time T8 has elapsed (step Sc7), if the indoor / outdoor temperature difference is equal to or less than the set value C (NO in step Sc8), the compressor is continuously operated (step Sc9), and the set value C If larger (YES at Step Sc8), the indirect outside air cooling cycle operation is performed again (Step Sc1).
[0027]
In the first to third embodiments, when there is a possibility of occurrence of cavitation, the input amount of the refrigerant pressure sending means 11 is set to 0 and the indoor / outdoor blowers 2 and 9 are set to the maximum air flow rate. You may make it operate at least one of the input amount of the pressure sending means 11, the air volume of the indoor side fan 2, the air volume of the outdoor side fan 9, and the opening degree of the expansion valve 16.
[0028]
【The invention's effect】
As described above, according to the present invention, by preventing the occurrence of cavitation, it becomes possible to smoothly perform the cooling operation by the refrigerant pressure feeding means using the low temperature outside air in the room containing the high heat generating device. As compared with a cooling device using a conventional compressor, power consumption can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an annual cooling type air conditioner according to a first embodiment of the present invention.
FIG. 2 is a flowchart for explaining the operation of the embodiment;
FIG. 3 is a block diagram showing a configuration of an annual cooling type air conditioner according to a second embodiment of the present invention.
FIG. 4 is a flowchart for explaining the operation of the embodiment;
FIG. 5 is a block diagram showing a configuration of an annual cooling type air conditioner according to a third embodiment of the present invention.
FIG. 6 is a flowchart for explaining the operation of the embodiment;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Evaporator 2 ... Indoor fan 5 ... Compressor 7 ... Compressor bypass valve 8 ... Condenser 9 ... Outdoor fan 11 ... Refrigerant pressure feed means 12 ... Refrigerant pressure feed means control device 13 ... Refrigerant pressure feed means bypass valve 15 ... Refrigerant Flow rate detection means 16 ... expansion valve 18 ... expansion valve bypass valve 19 ... calculation unit 21 ... liquid level detection means 24 ... temperature detection means 25 ... pressure detection means

Claims (3)

A compressor, a condenser provided outside the room, an expansion valve, a vapor compression cooling circuit that circulates the refrigerant by pipe connection of the evaporator provided inside the room, an outdoor fan that sends air to the condenser, and An indoor fan that sends air to the evaporator, and refrigerant pressure feeding means provided in a pipe between the condenser and the expansion valve, the refrigerant pressure feeding means being inactive, and the compressor being in an operating state In an annual cooling type air conditioner having a cooling function by a vapor compression type cooling cycle for performing cooling of the air and a cooling function by an indirect outside air cooling cycle for operating the refrigerant pressure-feeding means and cooling the room with the compressor in an inoperative state ,
Refrigerant flow rate measuring means for measuring the flow rate of the liquid refrigerant sent from the refrigerant pressure sending means during operation by the indirect outside air cooling cycle;
When the measurement result of the refrigerant flow rate measurement means becomes equal to or less than a preset constant value during the operation by the indirect outside air cooling cycle, the input amount of the refrigerant pressure supply means, the air volume of the indoor fan, and the outdoor fan Control means for controlling at least one of the air volume and the valve opening of the expansion valve,
The control means, when the number of times the measurement result of the refrigerant flow rate measurement means becomes equal to or less than a predetermined value set in advance exceeds a predetermined number within a predetermined time, the cooling cycle is changed from the indirect outside air cooling cycle to the vapor compression type. Annual cooling type air conditioner characterized by changing to a cooling cycle . A compressor, a condenser provided outside the room, an expansion valve, a vapor compression cooling circuit that circulates the refrigerant by pipe connection of the evaporator provided inside the room, an outdoor fan that sends air to the condenser, and An indoor fan that sends air to the evaporator, and refrigerant pressure feeding means provided in a pipe between the condenser and the expansion valve, the refrigerant pressure feeding means being inactive, and the compressor being in an operating state In an annual cooling type air conditioner having a cooling function by a vapor compression type cooling cycle for performing cooling of the air and a cooling function by an indirect outside air cooling cycle for operating the refrigerant pressure-feeding means and cooling the room with the compressor in an inoperative state ,
A liquid level detection means for detecting a liquid level height of the liquid refrigerant output from the condenser during operation by the indirect outside air cooling cycle;
When the detection result of the liquid level detection means becomes equal to or less than a preset constant value during operation by the indirect outside air cooling cycle, the input amount of the refrigerant pressure feeding means, the air volume of the indoor blower, and the outdoor blower Control means for controlling at least one of the air volume and the valve opening of the expansion valve,
The control means changes the cooling cycle from the indirect outside air cooling cycle to the vapor compression cooling cycle when a state in which the detection result of the liquid level detection means is not more than a predetermined constant value continues for a predetermined time or longer. year cooling-type air conditioner which is characterized in that. A compressor, a condenser provided outside the room, an expansion valve, a vapor compression cooling circuit that circulates the refrigerant by pipe connection of the evaporator provided inside the room, an outdoor fan that sends air to the condenser, and An indoor fan that sends air to the evaporator, and refrigerant pressure feeding means provided in a pipe between the condenser and the expansion valve, the refrigerant pressure feeding means being inactive, and the compressor being in an operating state In an annual cooling type air conditioner having a cooling function by a vapor compression type cooling cycle for performing cooling of the air and a cooling function by an indirect outside air cooling cycle for operating the refrigerant pressure-feeding means and cooling the room with the compressor in an inoperative state ,
Temperature detection means and pressure detection means for detecting the temperature and pressure of the liquid refrigerant output from the condenser during operation by the indirect outside air cooling cycle, respectively;
When supercooling degree which is calculated based on the output of the output and the pressure detecting means of said temperature detecting means during the operation by the indirect outdoor air cooling cycle is below a preset constant value, the input amount of the refrigerant pumping means Control means for controlling at least one of the air volume of the indoor fan, the air volume of the outdoor fan, and the valve opening of the expansion valve;
The control means changes the cooling cycle from the indirect outside air cooling cycle to the vapor compression cooling cycle when the state in which the degree of supercooling is equal to or less than a preset constant value continues for a predetermined time or more. Annual cooling type air conditioner.

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