Patent Application
20110219794
This application claims priority from Japanese Patent Application No. 2009-249002 filed on Oct. 29, 2009, the entire contents of which are incorporated herein by reference.
The present invention relates to an apparatus using a combustible refrigerant, such as an air-conditioning unit or a refrigeration unit, and more particularly, manufacture, shipment, storage, conveyance, and installation of the apparatus using the combustible refrigerant.
Recently, as attention on global environment increases, refrigerant that does not much affect destruction of ozone layer or global warming and that exhibits a low global warming potential (hereinafter referred to as “GWP”) has gained attention. As of the year 2009, attempts are made to establish regulations such that a low GWP refrigerant exhibiting a GWP of less than 150 should be used for vehicle air-conditioning units in Europe. Home air-conditioning units and business air-conditioning units are also required to use a low GWP refrigerant in order to prevent global warming. HC refrigerants exhibiting a low GWP of less than 150, such as propane, butane, and isobutene, and HFC refrigerants, such as HFO1234yf, have gained attention. Meanwhile, propane, butane, and isobutene of the HC refrigerants are combustible refrigerants. Thus, when using the HC refrigerant, safety must be assured by avoiding occurrence of firing of the refrigerant. On the contrary, the HFC refrigerant, such as HFO1234yf, is a slightly combustible refrigerant, and similarly, safety must be assured. There have hitherto been put forth many techniques for preventing occurrence of firing during operation of an air-conditioning unit or a refrigeration unit which operate by using the combustible refrigerant or the slightly combustible refrigerant. However, only are few techniques for preventing occurrence of firing during manufacturing, shipping, storing, conveying, and setting the air-conditioning unit or the refrigeration unit which operate by using the combustible refrigerant or the slightly combustible refrigerant have been put forth.
In related-art, there has been proposed a refrigerator including the following features (see; for example, JP-A-H09-229522 (pp. 2 to 5, FIG. 1)). Namely, an incombustible refrigerant is sealed into a refrigerant circuit of the refrigerator during storing and conveying processes. After the refrigerator has been installed at a safety location, the incombustible refrigerant is recovered outside of the refrigerator. Subsequently, an HC refrigerant which is a combustible refrigerant is sealed in the refrigerant circuit. By doing so, even if the refrigerator is dropped or toppled, or a fragile portion of the refrigerator, such as a pipe of the refrigerant circuit, is broken during the course of storage and conveyance of the refrigerator, only the incombustible refrigerant will leak. Hence, there is no possibility of occurrence of a fire accident.
Additionally, it is described in a related-art that a combustible refrigerant is sealed into the refrigerant circuit while an inside of an outdoor unit is held in a vacuum state or at a state near atmospheric pressure in a storing or conveying process (see; for example, JP-A-2000-46446 (pp. 3 to 5, FIG. 1)). Further, it is described that by doing so, even if the refrigerant leaks as a result of cracks having occurred in a pipe, or the like, for reasons of vibrations, or the like, in the storing or conveying process, a large quantity of combustible refrigerant will not leak, and therefore, possibility of occurrence of explosion or firing is extremely low.
In the method where the incombustible refrigerant is sealed into the refrigerant circuit during the storing or conveying process, operation for recovering the incombustible refrigerant at the time of installation of an air-conditioning unit or a refrigeration unit is not described in related-art and is a new operation. Thus, new problems such as increase in working time or workload during the installation work arise. Further, some refrigerant oil may also be recovered together with the recovery of the incombustible refrigerant, which will deteriorate reliability of an air-conditioning unit or a refrigeration unit. Further, when an inexperienced installation engineer recovers the incombustible refrigerant, the engineer may erroneously release the incombustible refrigerant into the atmosphere, which affects global warming.
Further, in the method where the combustible refrigerant is sealed in the refrigerant circuit in the storing and conveying processes while the inside of the outdoor unit is held in a vacuum state or at a state near atmospheric pressure, the outdoor units are densely stacked into layers. Therefore, even when an amount of refrigerant leaked from one unit is small, a total amount of leaked refrigerant becomes large, which in turn increase a possibility of occurrence of firing.
An aspect of the present invention provides an apparatus and a method that assure safety in processes for manufacturing, shipping, storing, and conveying an air-conditioning unit or a refrigeration unit using a combustible or a slightly combustible refrigerant and that do not incur an increase in time or workload during the installation of the air-conditioning unit or the refrigeration unit.
According to an exemplary embodiment of the present invention, when installing an outdoor unit to be used for an air-conditioning unit or a refrigeration unit, where an incombustible refrigerant is previously sealed in a refrigerant circuit component part of the outdoor unit and the outdoor unit is shipped from a factory, on a place to be used, a combustible or slightly combustible refrigerant is additionally sealed into a refrigerant circuit while the incombustible refrigerant sealed before shipment remains sealed in the refrigerant circuit component part of the outdoor unit.
Accordingly, when installing an outdoor unit to be used for an air-conditioning unit or a refrigeration unit, where the incombustible refrigerant is previously sealed in the refrigerant circuit component part of the outdoor unit and the outdoor unit is shipped from a factory, on a place to be used, a required amount of combustible or slightly combustible refrigerant is additionally sealed in the refrigerant circuit while the incombustible refrigerant sealed before shipment remains sealed in the refrigerant circuit component part of the outdoor unit without being recovered, whereby the outdoor unit can perform air-conditioning operation or refrigerating operation. Therefore, it is possible to assure safety in processes for shipping, storing, and conveying an air-conditioning unit or a refrigeration unit using a combustible or slightly combustible refrigerant, thereby lessening workload incurred during installation.
An exemplary embodiment of the present invention is hereunder described by reference to the drawings.
Circulation of a refrigerant in the refrigerant circuit is now described. For instance, during cooling operation, a low-pressure refrigerant sucked into the compressor 1 from the liquid reservoir 5 is compressed by the compressor 1, to thus become a high-temperature, high-pressure refrigerant. The refrigerant then flows into the outdoor heat exchanger 3 by way of the four way valve 2. The refrigerant flowed into the outdoor heat exchanger 3 exchanges heat with outdoor air of the outdoor unit 50, to thus become condensed, and then flows into the decompressor 4. The refrigerant thus flowed into the decompressor undergoes decompression in the decompressor 4, whereupon a temperature of the refrigerant decreases. The low-temperature, low-pressure refrigerant subjected to a temperature drop as a result of having been decompressed by the decompressor 4 is delivered to the indoor unit 60 by way of the liquid pipe connection valve 7 of the outdoor unit, the liquid extension pipe 11, and the liquid pipe connecting port 13 of the indoor unit. The refrigerant delivered to the indoor unit 60 flows into the indoor heat exchanger 9 and exchanges heat with indoor air of the indoor unit 60, to thus evaporate. The thus-evaporated refrigerant returns to the outdoor unit 50 by way of the gas pipe connecting port 12 of the indoor unit, the gas extension pipe 10, and the gas pipe connection valve 6 of the outdoor unit, to thus flow into the liquid reservoir 5 by way of the four way valve 2. By such a circulation of refrigerant in the refrigerant circuit, heat exchange between the refrigerant and air is performed in the indoor heat exchanger 9 in the indoor unit 60, thereby cooling the air of the indoor unit 60. Thus, air-conditioning operation is performed.
Further, during heating operation, the four way valve 2 switches a flow route of the refrigerant, thereby letting the indoor heat exchanger 9 condense the refrigerant and the outdoor heat exchanger 3 evaporate the refrigerant. Specifically, the refrigerant sucked from the liquid reservoir 5 and compressed by the compressor 1 flows into the indoor heat exchanger 9 by way of the four way valve 2, the gas pipe connection valve 6 of the outdoor unit, the gas extension pipe 10, and the gas pipe connecting port 12 of the indoor unit. The refrigerant flowed into the indoor heat exchanger 9 exchanges heat with the indoor air of the indoor unit 60 and becomes condensed. The refrigerant then flows into the decompressor 4 by way of the liquid pipe connecting port 13 of the indoor unit, the liquid extension pipe 11, and the liquid pipe connection valve 7 of the outdoor unit. The refrigerant subjected to a temperature drop as a result of having undergone decompression performed by the decompressor 4 is evaporated by the outdoor heat exchanger 3 and returns to the liquid reservoir 5 by way of the four way valve 2. By such a circulation of the refrigerant through the interior of the refrigerant circuit, heat exchange between the refrigerant and air is performed in the indoor heat exchanger 9 in the indoor unit 60, thereby heating the air of the indoor unit 60 and performing heating operation.
Incidentally, in the case of a cooling-only air-conditioning unit that does not require heating operation, the four way valve 2 can be omitted.
Circulation of the refrigerant through the interior of the refrigerant circuit will be described. The refrigerant sucked from the liquid reservoir 5 and compressed by the compressor 1 flows into the outdoor heat exchanger 3 by way of the four way valve 2. The outdoor heat exchanger 3 exchanges heat between refrigerant flowed into the outdoor heat exchanger 3 and outdoor air of the outdoor unit 50 and condenses the refrigerant, and the thus-condensed refrigerant flows into the decompressor 4. The decompressor 4 decompresses the inflow refrigerant, whereupon the temperature of the refrigerant drops. The refrigerant subjected to a temperature drop as a result of having undergone decompression performed by the decompressor 4 flows into the heat exchanger 15 of the freezer 61 by way of the liquid pipe connection valve 7 of the outdoor unit, the liquid extension pipe 11, and the liquid pipe connecting port 17 of the freezer 61. The refrigerant evaporated as a result of having exchanged heat with air in the freezer 61 flows into the liquid reservoir 5 by way of the gas pipe connecting port 16 of the freezing chamber 61, the gas extension pipe 10, the gas pipe connection valve 6 of the outdoor unit, and the four way valve 2. The air in the freezer 61 undergoes heat exchange by circulation of the refrigerant so that goods to be stored, such as food products, in the freezer 61 can be frozen. Even when the freezer 61 is a refrigerator that keeps goods to be stored, such as food products, cold, the refrigerator is identical with the freezer 61 in terms of configuration and system for circulating a refrigerant. When the freezer 61 is a freezer that freezes food products or a refrigerator that keeps the food products cold, the flow route of the refrigerant will not be required to be switched. Hence, the four way valve 2 can be omitted. However, in the case of a show case or an automatic vending machine, there may be a case where goods to be stored, such as food products, in the show case or the automatic vending machine are kept warm. For this reason, the flow route of the refrigerant is switched by the four way valve 2, thereby letting the heat exchanger 15 condense the refrigerant and the outdoor heat exchanger 3 evaporate the refrigerant. Circulation of the refrigerant in the refrigerant circuit is the same as that performed during heating operation. That is, the heat exchanger 15 heats air in the showcase or the automatic vending machine, whereby the goods in the showcase or the automatic vending machine are kept warm.
Circulation of the refrigerant in the refrigerant circuit will be described. When hot water is generated as in the case with a hot water supply, the refrigerant sucked from the liquid reservoir 5 and compressed by the compressor 1 flows into the load-side heat exchanger 20 by way of the four way valve 2. The load-side heat exchanger 20 is configured such that water flowed from the pipe connecting port 21 exchanges heat with the refrigerant, thereby generating hot water, and then exits from a pipe connecting port 22. The pipe connecting port 22 is equipped with an unillustrated tank, and the tank is used for using generated hot water for a hot water supply or heating operation. When the hot water is used for air-conditioning such as heating, the thus-generated hot water may be circulated, that is, passing through an air-conditioning unit that air-conditions an indoor space and returning to the connecting port 21, as a secondary refrigerant. The refrigerant flowed into the load-side heat exchanger 20 exchanges heat with water, undergoes condensation, and then flows into the decompressor 4. The refrigerant subjected to temperature drop as a result of having been decompressed by the decompressor 4 is evaporated by the outdoor heat exchanger 3 and returns to the liquid reservoir 5 by way of the four way valve 2. Through such circulation of the refrigerant through the interior of the refrigerant circuit, the load-side heat exchanger 20 exchanges heat between the refrigerant and water, thereby generating hot water and providing a hot water supply or heating an indoor space. When the outdoor unit performs cooling operation as an air-conditioning unit, the four way valve 2 is switched, and the load-side heat exchanger 20 generates cold water, and the cold water is supplied as a secondary refrigerant to the indoor air-conditioning unit, whereby cooling operation is performed. In the case of a hot water supply that does not involve generation of cold water, the four way valve 2 is not switched and hence, is omitted. Likewise, when the indoor air-conditioning unit is solely for cooling purpose, switching of the four way valve 2 is not performed and hence, is omitted.
A refrigeration unit can also be configured by utilization of the configuration of the outdoor unit shown in
Circulation of the refrigerant in the refrigerant circuit is the same as that performed during cooling operation. The antifreeze liquid cooled by the refrigerant in the load-side heat exchanger 20 is delivered as the secondary refrigerant to the freezer to cool air in the freezer and again returns to the load-side heat exchanger 20. Goods to be stored, such as food products, in the freezer are cooled. Even when the freezer is a refrigerator that keeps goods to be stored, such as food products, cold, the refrigerator is identical with the freezer in terms of configuration and system for circulating the refrigerant. However, when the freezer connected to the load-side heat exchanger 20 is a show case or an automatic vending machine, there may be a case where goods to be stored, such as food products, in the show case or the automatic vending machine will be kept warm. In this case, the flow route of the refrigerant is switched by the four way valve 2, thereby letting the load-side heat exchanger 20 heat the secondary refrigerant. Circulation of the refrigerant in the refrigerant circuit is the same as that performed for heating; namely, the secondary refrigerant heated by the refrigerant in the load-side heat exchanger 20 is delivered to the showcase or the automatic vending machine, thereby heating air in the showcase or the automatic vending machine and again returns to the load-side heat exchanger 20. Goods to be stored, such as food products, in the showcase or the automatic vending machine, are thereby kept warm. However, in the case of a freezer that freezes food products or a refrigerator that keeps the food products cold, neither the freezer nor the refrigerator are used for keeping the goods warm. Therefore, the flow route of the refrigerant does not need to be switched by switching the four way valve 2, and therefore, the four way valve 2 is omitted.
Next,
The above descriptions are about the steps of manufacturing the air-conditioning unit or the refrigeration unit using the outdoor unit 50. However, the same steps and sequence apply to the case of an air-conditioning unit or a refrigeration unit using the outdoor unit 51.
The above descriptions are about the steps of manufacturing the outdoor unit 50 of the air-conditioning unit. However, the same steps also apply to manufacture of a refrigeration unit.
The steps for manufacturing the outdoor unit 50 have been described thus far. Steps for manufacturing the outdoor unit 51 used for providing a hot water supply will be described hereinafter. The steps shown in
When the outdoor units 50 and 51 perform test working while the refrigerant is sealed in the units as described in connection with STEP 15 to STEP 17 in
Meanwhile, in relation to the incombustible refrigerant, a previously-sealed incombustible refrigerant is not recovered on site. Therefore, an HFC refrigerant, such as R410A and R407C, or a natural refrigerant like CO2 that is capable of phase change, to thus be able to use latent heat, under pressure conditions of a refrigerant that circulates through a refrigerant circuit during air-conditioning operation of an air-conditioning unit or refrigerating operation of a refrigeration unit. An inert gas, such as nitrogen, helium, and argon, is also available as an incombustible material. However, the inert gas is not capable of a phase change, to thus be able to use latent heat, under pressure conditions of a refrigerant that circulates through a refrigerant circuit during air-conditioning operation of the air-conditioning unit or refrigerating operation of the refrigeration unit. Therefore, the inert gas does not act as a refrigerant in the refrigerant circuit and is not suitable as an incombustible refrigerant of the present invention and hence not used.
The amount of incombustible refrigerant sealed in the refrigerant circuit component parts of the outdoor units 50 and 51 is determined so that a pressure of the incombustible refrigerant is an atmospheric pressure or more. Accordingly, even if the refrigerant circuit is accidentally brought into mutual communication with the atmosphere in any of the shipping step, the storing step, the conveying step, and the setup step, entry of the atmosphere into the refrigerant circuit component parts of the outdoor units 50 and 51 is prevented.
In relation to the refrigerant circuit of the air-conditioning unit and the refrigeration unit, guidelines, such as an intensity of the refrigerant circuit, are described in JISB8020, or the like, so as to prevent pipes of the refrigerant circuit from being damaged by a refrigerant gas sealed in the refrigerant circuit. A pressure limitation achieved as a result of intensity of the refrigerant circuit being designed so as to prevent occurrence of fractures, in compliance with the guidelines, is referred to as design pressure. Since the refrigerant circuits of the outdoor units 50 and 51 are designed so as to use a combustible low GWP refrigerant or a slightly combustible low GWP refrigerant, the outdoor units are equipped with a refrigerant circuit having strength of design pressure that prevents occurrence of fractures when the combustible low GWP refrigerant or the slightly combustible low GWP refrigerant is sealed in the refrigerant circuit. However, a density of the combustible low GWP refrigerant or the slightly combustible low GWP refrigerant is about 100 times or more than that of an incombustible refrigerant. Therefore, design pressure for the combustible low GWP refrigerant or the slightly combustible low GWP refrigerant becomes lower than design pressure for the incombustible refrigerant. Therefore, even when the incombustible refrigerant is sealed up to the design pressure for the combustible low GWP refrigerant or the slightly combustible low GWP refrigerant, the amount of sealed refrigerant becomes small, and hence a break or deformation, which would otherwise arise when the internal pressure of the refrigerant circuit component parts of the outdoor units 50 and 51 become too high, does not occur.
Procedures from the packing step corresponding to STEP 2 in
Further, the refrigerant circuit component part of the load unit, such as the indoor unit 60 and the freezer 61, does not have any sealing valve, such as the switching valve. Since the indoor unit 60 and the freezer 61 are shipped while their refrigerant circuit component parts remain in mutual communication with the atmosphere, they are originally free from a risk of fire. Further, a load unit, such as a hot water supply unit, connected to the outdoor unit 51 is not equipped with a refrigerant circuit. Accordingly, the load unit does not raise a fire problem, either.
In the conveying step corresponding to STEP 4 or 6 shown in
Meanwhile, conveying the air-conditioning unit or the refrigeration unit and the refrigerant cylinder in the same transport means does not raise any problem. All you need to do at that time is to take sufficient safety measures against toppling of the refrigerant cylinder. By doing so, even if the air-conditioning unit or the refrigeration unit conveyed concurrently with the refrigerant cylinder has toppled down, the combustible or slightly combustible refrigerant filled in the refrigerant cylinder will not leak.
In storing step corresponding to STEP 5 shown in
In order to notify people around the outdoor unit that the outdoor unit using a combustible or slightly combustible refrigerant in the conveying step corresponding to STEP 4 or STEP 6 shown in
Next, the installation/setup step shown in
Through the operations mentioned above, the combustible or slightly combustible refrigerant can additionally be sealed without recovering the incombustible refrigerant from the refrigerant circuit component part of the outdoor unit 50. Additionally, the refrigeration unit including the freezer 61 and the outdoor unit 50 can be installed and set through substantially the same steps.
In STEPS 57 to 59, after connection of the airtight container of the refrigerant A, the switching valves 6d and 7d can be opened before opening of the switching valve 6e, thereby bringing the refrigerant circuit component part of the indoor unit 60 and the refrigerant circuit component part of the outdoor unit 50 into mutual communication and subsequently, the switching valve 6e can be opened to seal the refrigerant A into the refrigerant circuit component part.
Explanations have been provided by reference to the example in which the switching valve 6e for opening and closing the refrigerant sealing connecting port 6c and the connecting port 6c are provided in the gas pipe connection valve 6. However, the connecting port 6c and the switching valve 6e may be provided to the refrigerant pipes of the indoor unit 60 or the extension pipes 10 and 11. In this case, the setup and installation step remains unchanged, and the vacuum pump is connected to the connecting port 6c in STEP 54 to STEP 58, and the switching valve 6e is opened, thereby producing a vacuum in the refrigerant circuit component part of the indoor unit 60. After the vacuum has been produced, the switching valve 6e is temporarily closed. The vacuum pump is disconnected, and the refrigerant cylinder is connected to the connecting port 6c, whereby a refrigerant is sealed in the refrigerant circuit component part. After completion of sealing operation, the switching valve 6e is closed, and the refrigerant cylinder is disconnected. Steps subsequent to STEP 59 are the same as those described previously.
Further, the refrigerant sealing connecting port 6c and the switching valve 6e can be provided at any position between the pipe connecting port 6a of the gas pipe connection valve 6 and the four way valve 2 shown in
Similarly, the refrigerant sealing connecting port 6c and the switching valve 6e can be provided at any position between the pipe connecting port 7a of the liquid pipe connection valve 7 and the decompressor 4 shown in
Next, the step of installing and setting the outdoor unit 51 will be described.
Through the operations mentioned above, the combustible or slightly combustible refrigerant can additionally be sealed without recovering the incombustible refrigerant from the refrigerant circuit component part of the outdoor unit 50. Additionally, the refrigeration unit including the freezer and the outdoor unit 51 can be installed and set through substantially the same steps.
When circulating through the refrigerant circuit at internal pressure of the refrigerant circuit achieved during the course of air-conditioning operation or refrigerating operation, for instance, 0.3 to 4.1 MPa, the combustible or slightly combustible low GWP refrigerant undergoes a phase change from liquid to gas in the heat exchanger, or the like, that is an evaporator, or a phase change from gas to liquid in the heat exchanger, or the like, that is a condenser. The heat exchanger thereby performs heat exchange operation, thereby air-conditioning a room space or freezing food products. Since the incombustible refrigerant is selected from HFC refrigerants, such as R410A and R407C, or natural refrigerants, such as CO2, the refrigerant causes a phase change from liquid to gas in the heat exchanger, or the like, that is an evaporator, or a phase change from gas to liquid in the heat exchanger, or the like, that is a condenser, when circulating through the refrigerant circuit under internal pressure conditions for the refrigerant circuit achieved during air-conditioning operation or refrigerating operation. Therefore, when the combustible or slightly combustible low GWP refrigerant performs heat exchange by circulating through the refrigerant circuit, the incombustible refrigerant does not hinder heat exchange action of the combustible or slightly combustible low GWP refrigerant. Moreover, since the incombustible refrigerant itself performs heat exchange by circulation, heat exchange capability is not hindered.
Further, because the amount of incombustible refrigerant sealed is determined so that a pressure of the incombustible refrigerant is equal to or higher than the atmospheric pressure and equal to or lower than the design pressure of the refrigerant circuit of the outdoor unit using a combustible or slightly combustible low GWP refrigerant, the incombustible refrigerant is sealed in small amount that is about one-hundredth of an amount of combustible or slightly combustible low GWP refrigerant, which will be additionally sealed later, or less. Since the amount of incombustible refrigerant that performs heat exchange by circulating through the refrigerant circuit is relatively small, heat exchange capability of the combustible or slightly combustible low GWP refrigerant is sufficiently exhibited.
Since both of the outdoor units 50 and 51 are large scale refrigerant circuits, an amount of refrigerant more than necessary is sealed in the refrigerant circuits during air-conditioning or refrigerating operation, in order to sufficiently exhibit refrigerating capability by accommodating to a difference in setup conditions arising on site. Excessive refrigerant is temporarily recovered and stored in the liquid reservoir 5. Therefore, even when the amount of incombustible refrigerant sealed is an amount of refrigerant fulfilling the design pressure of the refrigerant circuit of the outdoor unit using a combustible or slightly combustible low GWP refrigerant, the amount of incombustible refrigerant sealed is still extremely smaller than the amount of combustible or slightly combustible low GWP refrigerant sealed on site. Further, in the air-conditioning unit or the refrigeration unit of the present invention, the incombustible refrigerant is sealed only in the refrigerant circuit component part of the outdoor unit 50. Thus, from the viewpoint of an entire refrigerant circuit made by connecting the vacuum refrigerant circuit component part of the indoor unit 60 or the freezer 61 with the vacuum liquid extension pipe 11 and the gas extension pipe 10, the relative amount of incombustible refrigerant becomes even smaller. Therefore, even when the incombustible refrigerant circulates through the refrigerant circuit, the incombustible refrigerant does not hinder the heat exchange capability exhibited by the combustible or slightly combustible refrigerant.
For these reasons, even when the incombustible refrigerant previously sealed in the refrigerant circuit component part of the outdoor unit is not recovered, the air-conditioning unit or the refrigeration unit does not induce large deterioration of performance. Rather, predetermined capability achieved when the combustible or slightly combustible low GWP refrigerant is sealed can be exhibited.
Even when a high GWP incombustible refrigerant having a GWP of the order of 2000 to 1500 is used for the outdoor units 50 and 51 as compared with a low GWP combustible or slightly combustible refrigerant having a GWP of less than 150 sealed on site, the amount of the incombustible refrigerant sealed before factory shipment is extremely small. Therefore, in view of the entire refrigerant including the refrigerant additionally sealed during installation and setup operation, GWP is less than 150. Thus, an air-conditioning unit or a refrigeration unit in which a low GWP refrigerant having a GWP of less than 150 is sealed can be provided.
Further, when a refrigerant sealed and used during air-conditioning or refrigerating operation is a combustible HC refrigerant, a small amount of HC refrigerant may be previously mixed in the incombustible refrigerant sealed in an outdoor unit shipped from the factory. The HC refrigerant exhibits high compatibility with a mineral oil that is a lubricant for the compressor, whilst the incombustible HFC refrigerant previously sealed in the outdoor unit exhibits low compatibility with the mineral oil. In the installation and setup step corresponding to STEP 7 shown in
Meanwhile, R422D and R600a are combustible refrigerants. In order to let R422D or R600a sealed concurrently with the incombustible refrigerant circulate and return to the compressor, a sufficient amount of combustible refrigerant is as small as about 10 to 20 percents of the amount of mineral oil. Therefore, even if a refrigerant leaks as a result of the outdoor unit having fallen or toppled down in the storage or conveying step, a possibility of occurrence of firing due to leakage of the refrigerant is low. Further, even when there is used an HC refrigerant sealed during air-conditioning or refrigerating operation in place of R422D or R600a, the amount of HC refrigerant is about 10 to 20 percents of the amount of mineral oil as in the case with R422D or R600a. Therefore, even if a refrigerant leaks as a result of the outdoor unit having fallen or toppled down in the storage or conveying step, a possibility of occurrence of firing due to leakage of the refrigerant is low.
Further, in the case of an outdoor unit in which an HFC refrigerant, such as HFO123yf, is sealed during air-conditioning or refrigerating operation, there is used a refrigerant oil that exhibits high compatibility with the HFC refrigerant and that is a lubricant for the compressor, regardless of whether the refrigerant oil is combustible or incombustible. Therefore, there is no need to mix an HC refrigerant in the incombustible refrigerant before sealing.
As described above, when the outdoor unit that is shipped from the factory after an incombustible refrigerant has been sealed in a refrigerant circuit thereof is set at a place where the user is to use the outdoor unit, the outdoor unit can be used by additionally sealing a required amount of combustible refrigerant or slightly combustible refrigerant into a refrigerant circuit without recovery of the incombustible refrigerant sealed before shipment from the refrigerant circuit, that is, while the incombustible refrigerant is sealed in the refrigerant circuit. Therefore, there can be provided an air-conditioning unit or a refrigeration unit using a combustible refrigerant or a slightly combustible refrigerant, wherein safety in steps of shipping, storing, and conveying the air-conditioning unit or the refrigeration unit can be assured and work load imposed during setup operation on site can be lessened.
Further, according to the present embodiment of this invention, even when the air-conditioning unit or the refrigeration unit has toppled down or fallen in the storage or conveying step, the possibility of the refrigerant catching fire is low. Further, the incombustible refrigerant does not need to be recovered during setup operation. Therefore, the possibility of the incombustible refrigerant being released into the atmosphere is low.
Further, according to the present embodiment of this invention, an HC refrigerant, such as propane, butane, and isobutene, and an HFC refrigerant, such as HFO1234yf, which have a low GWP refrigerant exhibiting a GWP of less than 150, are used as a combustible or slightly combustible refrigerant sealed in an air-conditioning unit or a refrigeration unit at the timing of inspection in manufacturing steps and after setup on site, so to be useable. Thus, ozone layer will not be destroyed and the refrigerant exhibits a small GWP, and therefore, is friendly to the global environment.
Further, according to the present embodiment of this invention, an HFC refrigerant, such as R410A and R407C, or a natural refrigerant, such as CO2, is used as an incombustible refrigerant to be sealed before shipment from the factory. Since the incombustible refrigerant changes its phase from liquid to gas or gas to liquid under pressure conditions for the refrigerant required during air-conditioning or refrigerating operation, heat exchange of the additionally sealed HC refrigerant or HFC refrigerant is not hindered. Further, even if a refrigerant leaks as a result of the outdoor unit having fallen or toppled down in the storage or conveying step, the possibility of occurrence of firing due to leakage of the refrigerant is low.
Further, the refrigerant circuit of the present embodiment of this invention is a large scale refrigerant circuit having a liquid reservoir for storing excessive refrigerant. When the air-conditioning unit or the refrigeration unit is installed and set on site, in order to accommodate a difference in setup conditions on site and sufficiently exhibit refrigerating capability, an additionally sealed combustible or slightly combustible refrigerant is sealed in an amount more than necessary. Thus the amount of incombustible refrigerant sealed before shipment from the factory is smaller than the amount of additionally sealed combustible or slightly combustible refrigerant. Meanwhile, even if the incombustible refrigerant circulates through the refrigerant circuit, heat exchange capability exhibited by the combustible or slightly combustible refrigerant is not hindered, and hence, incombustible refrigerant does not need to be recovered.
Further, according to the present embodiment of this invention, the amount of incombustible refrigerant sealed before shipment from the factory is smaller than the amount of combustible or slightly combustible low GWP refrigerant additionally sealed during installation and setup operation. Therefore, even when a small amount of incombustible refrigerant exhibiting a high GWP is mixed with the combustible or slightly combustible low GWP refrigerant, the GWP exhibited by the entire refrigerant can be maintained less than 150. Accordingly, there can be provided an air-conditioning unit or a refrigeration unit in which a low GWP refrigerant fulfilling a target GWP of less than 150 is sealed.
Further, according to the present embodiment of this invention, a small amount of HC refrigerant is previously mixed in an incombustible refrigerant. Therefore, even if the compressor is started while sealing of the HC refrigerant is forgotten during work for setting an outdoor unit having a refrigerant circuit component part in which an HFC refrigerant has previously been sealed, an HC refrigerant exhibiting high compatibility with a mineral oil circulates through the refrigerant circuit along with the mineral oil and returns to the compressor. Thus, depletion of oil in the compressor can be avoided, and a failure does not take place in the compressor. The HC refrigerant employed at this time can be an HC refrigerant sealed during air-conditioning or refrigerating operation or another HC refrigerant, such as R422D and R600a, which does not hinder circulation of the HC refrigerant additionally sealed on site. Further, although R422D or R600a is a combustible refrigerant, the amount of R422D or R600a included in the incombustible refrigerant is small. Hence, even if a refrigerant leaks as a result of the outdoor unit having fallen or toppled down in the storage or conveying step, a possibility of occurrence of firing due to leakage of the refrigerant is low.
Further, according to the present embodiment of this invention, means for notifying people around an outdoor unit that an incombustible refrigerant is sealed in the outdoor unit during storage, shipment, and conveying operations and that a combustible or slightly combustible refrigerant is sealed in the outdoor unit when the outdoor unit is set, is provided on a surface of a packing material of the outdoor unit in steps of manufacturing outdoor units for refrigeration units or air-conditioning units. Thus, it is possible to notify people around the outdoor unit that there is little possibility of occurrence of firing even if the outdoor unit toppled down in storage, shipment, and conveying steps.
Moreover, according to the present embodiment of this invention, the combustible or slightly combustible refrigerant sealed in the outdoor unit is stored, shipped, and conveyed in a space separated from the outdoor unit in steps of shipping, storing, and conveying the outdoor unit of the air-conditioning unit or the refrigeration unit. Therefore, even if a combustible refrigerant leaks as a result of the outdoor unit having fallen or topped down in the storage, shipment, or conveying step, there is little possibility of occurrence of firing due to leakage of the refrigerant.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-249002 | Oct 2009 | JP | national |
