EP2312241B1

EP2312241B1 - Refrigerating cycle apparatus, and air-conditioning apparatus

Info

Publication number: EP2312241B1
Application number: EP09770035.5A
Authority: EP
Inventors: Hiroyuki Morimoto; Kazuki Okada; Tetsuji Saikusa
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2008-06-24
Filing date: 2009-06-12
Publication date: 2019-11-27
Anticipated expiration: 2029-06-12
Also published as: JPWO2009157325A1; EP2312241A1; EP2312241A4; US20110079040A1; WO2009157325A1; CN102077040A

Description

Technical Field

The present invention relates to a refrigerating cycle device such as an air conditioner, a water heater and the like. Particularly, reliability of a refrigerating cycle device is improved by providing removing means for removing substances that react with an unstable refrigerant.

Background Art

In general, in a refrigerating cycle device using a refrigerating cycle (heat-pump cycle) such as an air conditioner, a freezer, a water heater and the like, basically, a compressor, a condenser (heat exchanger), an expansion valve, and an evaporator (heat exchanger) are connected by piping so as to constitute a refrigerant circuit through which a filled refrigerant is circulated. The refrigerant compressed in the compressor becomes a high-temperature and high-pressure gas refrigerant and is fed into the condenser. The refrigerant having been fed into the condenser is liquefied by emitting heat through heat exchange with a heat-exchange target. The liquefied refrigerant is decompressed by the expansion valve and turned into a gas-liquid two-phase flow state and gasified (evaporated) by absorbing heat through heat exchange in the evaporator, returned to the compressor again and circulated.
Here, there are many types of refrigerants circulating through the refrigerant circuit according to applications and physical characteristics, and some of them are refrigerants containing chemical substances affecting global warming. From a viewpoint of preventing global warming, a refrigerant having as small global warming coefficient (GWP: a degree of incurring global warming with respect to a substance, which is a greenhouse effect gas, represented by a coefficient determined on the basis of knowledge internationally approved as numeral values indicating a ratio to the degree regarding carbon dioxide) as possible is preferably used.
For example, carbon dioxide (CO₂) has a considerably small global warming coefficient, but efficiency of the refrigerating cycle is lowered and power consumption is increased. Also, since pressure resistance of equipment, piping and the like needs to be raised in general as compared with a case using a refrigerant circulated in a refrigerant circuit (R410A refrigerant, for example), a weight of the entire apparatus is increased, which results in cost-up and prevents popularization.
Then, an HFO (Hydro Fluoro Olefin) refrigerant (hereinafter referred to as an HFO refrigerant) is proposed. The HFO refrigerant has a small global warming coefficient and better energy efficiency than carbon dioxide and is an effective refrigerant from a viewpoint of a global environment. Also, since its boiling point is high and pressure of the refrigerant in the refrigerant circuit is low, there is no need to raise the pressure resistance. However, the HFO refrigerant has a characteristic that its chemical reactivity is high due to a double bond in an atomic bond constituting a substance (thus, the global warming coefficient gets smaller). Therefore, if impurities other than the refrigerant are present in the refrigerant circuit, the refrigerant reacts with the impurities and is deteriorated, which is a problem.
If the refrigerant is deteriorated, the high pressure gets higher or a discharge temperature becomes higher, and efficiency of the refrigerating cycle is drastically lowered. Also, a chemically reacted new substance further reacts with refrigerant oil, which generates sludge or blocks a thin pipe such as a capillary tube or an expansion valve, which is a problem.
As mentioned above, the HFO refrigerant has a low warming coefficient and is environmentally friendly, but deterioration of the refrigerant itself should be prevented in order to be used as a refrigerant in a vapor compression refrigerating cycle, while reliability is ensured. Therefore, in order to prevent circulation of an oxygen component in the refrigerant circuit, a method of providing oxygen adsorbing means for adsorbing oxygen is disclosed (See Patent Document 1, for example).

Citation List

Patent Document

PTL 1: Japanese Unexamined Patent Application Publication No. 2007-315663 (Fig. 1)
JP H07 159004A discloses a refrigerating cycle device which uses an adsorbent for adsorbing air in the refrigerating cycle of the outdoor unit. The adsorbent is a material which can adsorb two or more of gases such as moisture, oxygen and carbon dioxide in the air which is filled into a vessel forming a part of the refrigerating cycle.
Further, JP H07 294065A relates to a refrigeration system which uses a first filter filled with adsorbent to remove water and methane, and a second filter filled with adsorbent to remove non-condensable gases such as air.
JP H04 302967 relates to a refrigeration system using zeolites having a pore size between 0.3 and 0.4 nm to remove water from a refrigerant, yet uses another method to remove oxygen.

Summary of Invention

Technical Problem

However, since oxygen is not the only substance to become an impurity in the refrigerant circuit, even if the HFO refrigerant is sealed by adsorbing oxygen as above, it is highly likely that the HFO refrigerant is deteriorated, and efficiency and reliability of a refrigerating cycle device is lowered over time. Thus, in order to prevent deterioration of the HFO refrigerant, further measures are required.
The present invention was made in order to solve the above problems and has an object to obtain a refrigerant cycle device or the like that can prevent impurities contained in a refrigerant circuit from circulating in the refrigerant circuit and can effectively use the HFO refrigerant or the like.

Solution to Problem

A refrigerating cycle according to the invention is defined in claim 1.

Advantageous Effects of Invention

According to the refrigerating cycle device of the present invention, since the air adsorbing means is provided on the refrigerant circuit so as to adsorb an oxygen molecule and a nitrogen molecule in the air of the refrigerant circuit, the oxygen molecule and the nitrogen molecule to become impurities can be prevented from circulating. Therefore, when the HFO-1234yf refrigerant which has double bond and is chemically unstable is circulated through the refrigerant circuit, the HFO refrigerant and the air can be prevented from deteriorating or the like by chemical reaction or the like, performances of the refrigerating cycle device can be maintained for a long time, and moreover, reliability can be ensured. Also, since deterioration of the refrigerant can be prevented and feeding of a heat quantity can be maintained without applying a load on the compressor, energy can be saved. Since the HFO refrigerant tetrafluoropropylene (HFO-1234yf) is used as a refrigerant at this time has a global warming coefficient equivalent to that of carbon dioxide, which is a natural refrigerant, for example, and is a so-called nonflon refrigerant, the refrigerant is suitable from a viewpoint of the environment.

Brief Description of Drawings

[Fig. 1] Fig. 1 is a diagram of a basic configuration of a refrigerating cycle device according to Embodiment 1 of the present invention.
[Fig. 2] Figs. 2 are diagrams illustrating a configuration or the like of air adsorbing means 3 according to Embodiment 1.
[Fig. 3] Fig. 3 is a diagram illustrating an example of an installation position of the air adsorbing means 3 according to Embodiment 1.
[Fig. 4] Fig. 4 is a diagram illustrating another example of an installation position of the air adsorbing means 3 according to Embodiment 1.
[Fig. 5] Fig. 5 is a system configuration diagram of the refrigerating cycle device according to Embodiment 2, which describes a refrigerating cycle not part of the invention.
[Fig. 6] Fig. 6 is a diagram illustrating a configuration or the like of air adsorbing means 3 according to Embodiment 2.
[Fig. 7] Fig. 7 is a diagram illustrating an example not part of the invention to which air separating / removing means 11 is applied.
[Fig. 8] Fig. 8 is a diagram illustrating an example of an installation position of the air separating / removing means 11 according to Embodiment 2.

Description of Embodiments

Embodiment

1

An embodiment of the present invention will be described below referring to the attached drawings.
Fig. 1 is a diagram illustrating a basic configuration of a refrigerating cycle device according to Embodiment 1 of the present invention. Arrows 100 in Fig. 1 indicate a direction along which a refrigerant flows. In Fig. 1, the refrigerating cycle device has a compressor 1, a condenser 2, air adsorbing means 3, a throttle device (expansion valve) 4, and an evaporator 5. Each device (element part) is connected to each other by piping so as to constitute a refrigerant circuit. In the refrigerant circuit, a refrigerant to be circulated is sealed. As the refrigerant, in this Embodiment, a refrigerant having a double bond in an atomic bond such as CF₃CH = CH₂, CF₃CF = CF₂ including an HFO refrigerant containing tetrafluoropropene (represented by CF₃CF = CH₂: 2,3,3,3-Tetrafluoropropene, HFO-1234yf) is sealed.
The compressor 1 sucks the refrigerant to be circulated through the refrigerant circuit and compresses and pressurizes it. The condenser 2 performs heat exchange between a gas state refrigerant discharged by the compressor 1 (hereinafter referred to as a gas refrigerant) and a heat-exchange target and emits a heat quantity in the refrigerant so as to heat the heat-exchange target.
The air adsorbing means 3 is means for adsorbing air in the refrigerant circuit. Usually, a vacuuming process is provided before the refrigerant is filled in the refrigerating cycle device in order to vacuum the inside of the refrigerating cycle device. However, even with vacuuming, an air amount in the refrigerating cycle device cannot be brought to zero (fully vacuum state). Actually, approximately 130 to 250 Pa (approximately 1 to 2 Torr) is a limit. Thus, air is present all the time as an impurity in the refrigerant circuit of the refrigerating cycle device. Here, a presence ratio between nitrogen and oxygen in the air is 8 : 2, and oxygen and nitrogen (particularly nitrogen) occupy the most part. Thus, the air adsorbing means 3 according to the invention is supposed to adsorb oxygen molecules and nitrogen molecules. The air adsorbing means 3 will be described later in detail.
The throttle device 4 adjusts a flow rate of the refrigerant and lowers the pressure of the refrigerant (decompression). The evaporator 5 performs heat exchange between a gas-liquid two-phase refrigerant whose pressure is lowered by the throttle device 4 (refrigerant in which a gas refrigerant and a liquid-state refrigerant (hereinafter referred to as a liquid refrigerant) coexist) and a heat-exchange target, has a heat quantity absorbed by the refrigerant, evaporated, and gasified. The heat-exchange target is cooled. Here, a level of the pressure in the refrigerant circuit is not determined by a relationship with a pressure to be a reference but is indicated as a relative pressure determined by compression of the compressor 1, refrigerant flow-rate control of the throttle device 4 and the like. The same applies to a degree of the temperature.
Subsequently, an operation of the refrigerating cycle device according to this Embodiment will be described based on a flow of the refrigerant. The refrigerant having been compressed and pressurized by the compressor 1 passes through the piping and is fed into the condenser 2. The refrigerant having passed through the condenser 2 is condensed and liquefied. At this time, the refrigerant emits heat, by which the heat-exchange target is heated.
The liquefied refrigerant passes through the air adsorbing means 3 and is fed into the throttle device 4. The liquid-state refrigerant is decompressed while passing through the throttle device 4, becomes a refrigerant in the gas-liquid two-phase flow state (hereinafter referred to as a gas-liquid two-phase refrigerant) and is fed into the evaporator 5. The gas-liquid two-phase flow state refrigerant having passed through the evaporator 5 is evaporated and gasified. The gasified refrigerant is sucked into the compressor 1 again.
Figs. 2 are diagrams illustrating a configuration of the air adsorbing means 3. Subsequently, a configuration or the like of the air adsorbing means 3, which is a point of the present invention, will be described. Fig. 2A illustrates a sectional view of the air adsorbing means 3, and Fig. 2B illustrates filters (mesh) 3e, 3f, which is one of constituent elements of the air adsorbing means 3. As shown in Fig. 2A, the air adsorbing means 3 in this Embodiment is configured by a casing (container) 3a, an adsorbing material portion 3b filled with an adsorbing material, an inflow pipe 3c, an outflow pipe 3d, and the filters 3e, 3f. However, the configuration is not limited to this but means can be added or the like as necessary.
Here, a flow of the refrigerant in the air adsorbing means 3 will be described. As described above, the refrigerant having passed through the condenser 2 flows in through the inflow pipe 3c of the air adsorbing means 3, passes through the filter 3e and flows into the adsorbing material portion 3b. Here, the filter 3e traps a foreign substance inflowing with the refrigerant and prevents adhesion of the foreign substance to the adsorbing material in the adsorbing material portion 3b. By preventing adhesion of the foreign substance to the adsorbing material portion 3b, deterioration of the adsorbing material can be prevented, and stable performances can be obtained. Then, from the refrigerant flowing into the adsorbing material portion 3b, the adsorbing material of the adsorbing material portion 3b adsorbs only an air component (oxygen and nitrogen) contained in the refrigerant. The refrigerant whose air component has been adsorbed flows out of the outflow pipe 3d through the filter 3f and is fed into the throttle device 4.
Here, by means of the refrigerant flowing to the adsorbing material portion 3b, the adsorbing material in the adsorbing material portion 3b might be pulverized. If the pulverized adsorbing material flows out of the air adsorbing means 3 and circulates with the refrigerant in the refrigerant circuit, occlusion might be induced in members such as a capillary tube or the throttle device 4, which is a narrow flow passage. Also, it might cause a failure of the compressor 1. Then, the filter 3f is provided so that the pulverized adsorbing material is trapped and prevented from flowing out of the air adsorbing means 3. Therefore, the filer 3f is an important component in ensuring reliability of the air adsorbing means 3 and thus, the refrigerating cycle device.
According to the invention, as the adsorbing material in the adsorbing material portion 3b, zeolite which has excellent chemical stability and can strongly adsorb a substance with a low concentration (low partial pressure) is used. A mechanism for adsorbing air by zeolite is adsorption by trapping an oxygen molecule and a nitrogen molecule in a manner of a molecular sieve. Thus, in order to selectively adsorb only air by the adsorbing material 3b, a pore size of zeolite (here, it is supposed to be a diameter) should be not smaller than a diameter according to the air component and smaller than a diameter according to the HFO refrigerant. Due to this restriction, the pore size of the zeolite is inevitably determined. Here, a size of a nitrogen molecule, which is a major component of the air, is approximately 0.36 nm (3.6 angstrom) and a size of an oxygen molecule is approximately 0.34 nm (3.4 angstrom). Thus, even if the adsorbing material is optimized from a viewpoint of oxygen adsorption and the pore size of the adsorbing material is set at 0.35 nm (3.5 angstrom), the nitrogen molecule is larger than the oxygen molecule and cannot be removed. Also, a dryer which has been used is intended to adsorb moisture, and a pore size of the adsorbing material is in the vicinity of 0.29 nm (2.9 angstrom) (the size of a water molecule is 2.8 angstrom), therefore the nitrogen molecule and the oxygen molecule cannot be removed. From the above, the pore size of the adsorbing material needs to be approximately 0.36 nm in accordance with the nitrogen molecule.
On the other hand, the molecular size of the HFO-1234yf refrigerant is approximately 0.40 nm. Thus, by setting a pore size dp of the adsorbing material for removing oxygen and nitrogen at 0.36 nm < dp <0.40 nm, the air component can be selectively adsorbed. Here, according to the invention, zeolite is used as the adsorbing material, but in refrigerating cycle devices not part of the present invention the adsorbing material is not limited only to zeolite. In these refrigerating cycle devices not part of the invention, any adsorbing material such as silica gel, activated coal, mesoporous silica and the like, for example, can achieve the similar effect as long as it has a pore size of 0.36 nm < dp <0.40 nm as mentioned above.
An installation position of the air adsorbing means 3 will be described below. In Fig. 1, it is installed in a high-pressure liquid line (between the condenser 2 and the throttle device 4. A liquid refrigerant on the high-pressure side flows in the refrigerant circuit) on a downstream side of the condenser 2. When passing through the air adsorbing means 3, for example, the refrigerant generates pressure loss therein. The pressure loss generated in the refrigerant deteriorates (operation) efficiency of the refrigerating cycle device. However, by installing the means in the high-pressure liquid line, the pressure loss of such a degree that is generated in the air adsorbing means 3 can be considered as a part of a decompression operation in the throttle device 4 and does not affect efficiency of the refrigerating cycle device. Therefore, the air adsorbing means 3 is preferably installed in the high-pressure liquid line basically from a viewpoint of efficiency of the refrigerating cycle device.
Fig. 3 is a diagram illustrating an example of the installation position of the air adsorbing means 3. In Fig. 3, a case will be described in which the air adsorbing means 3 is installed in a low-pressure gas line (between the evaporator 5 and an intake side of the compressor 1. A gas refrigerant on the low-pressure side flows in the refrigerant circuit) on the downstream side of the evaporator 5. In Fig. 3, an oil separator 7 separates a lubricant discharged from the compressor 1 with the refrigerant from the refrigerant. A capillary tube 9 adjusts a flow rate when the separated lubricant is returned to the compressor 1. The oil separator 7 and the capillary tube 9 are connected to the intake side and the discharge side of the compressor 1 in parallel with the refrigerant circuit so as to constitute an oil return circuit 10.
In the case of an operation to reduce sub-cooling, for example, if the air adsorbing means 3 is installed in the high-pressure liquid line as in the above-mentioned Fig. 1, the pressure loss in the air adsorbing means 3 causes generation of air bubbles in the refrigerant (a part of the refrigerant is evaporated), and the refrigerant is brought into the gas-liquid two-phase state in a stage prior to an inflow into the throttle device 4. If the gas-liquid two-phase refrigerant flows into the throttle device 4, a pressure is violently fluctuated in a short time, and a hunting phenomenon or the like might occur in order to follow the movement, which might make control unstable. Thus, in the case of the operation which would reduce sub-cooling, the air adsorbing means 3 is preferably disposed in the low-pressure gas line depending on the cases.
Also, since the adsorbing material exerts better adsorbing performance if the temperature is lower in general, an amount of the adsorbing material can be reduced under a low-temperature environment if the same amount of air is to be adsorbed, for example. Thus, by installing the air adsorbing means 3 in the low-pressure gas line through which the low-temperature refrigerant passes, the size of the air adsorbing means 3 can be reduced, and costs relating to the air adsorbing means 3 can be declined. In this way, it is only necessary that the air adsorbing means 3 is simply provided on the low-pressure gas line, but the pressure loss generated in the air adsorbing means 3 might give too large impact on the efficiency of the refrigerating cycle device.
Thus, a bypass pipe for bypassing a part of the refrigerant is provided in the low-pressure gas line so as to form a bypass circuit 6, and the air adsorbing means 3 is disposed in the bypass circuit 6. By having a part of the refrigerant pass through the air adsorbing means 3 as above, a refrigerant flow rate passing through the air adsorbing means 3 is reduced, by which the pressure loss by the air adsorbing means 3 in the low-pressure line is decreased and efficiency drop of the refrigerating cycle device is minimized.
Here, as shown in Fig. 3, the air adsorbing means 3 is preferably provided at a position on the upstream side from the oil return circuit 10 from the oil separator. Even in the low-pressure gas line, on the downstream of the oil return circuit, an oil amount is large, and the oil adheres to the adsorbing material, which deteriorates performances of the adsorbing material, and the means is preferably installed on the upstream from a merger point with the oil return circuit.
Fig. 4 is a diagram illustrating another example of the installation position of the air adsorbing means 3. As shown in Fig. 4, the air adsorbing means 3 is installed in the oil return circuit 10. The air contained in refrigerator oil is adsorbed by the air adsorbing means 3. By providing the air adsorbing means 3 in the oil return circuit 10, the pressure loss generated in the air adsorbing means 3 does not affect the refrigerant circuit, and efficiency and controllability of the refrigerating cycle device is not affected.
As mentioned above, according to the refrigerating cycle device of Embodiment 1, by using the HFO refrigerant as a refrigerant circulating through the refrigerant circuit, since it is a so-called non-flon refrigerant having the global warming coefficient equivalent to that of carbon dioxide, which is a natural refrigerant, the refrigerating cycle device friendly to the global environment can be obtained. Also, since the air adsorbing means 3 is provided in the refrigerant circuit so that the oxygen molecule and the nitrogen molecule in the air remaining in the refrigerant circuit even after vacuuming, for example, are trapped, the oxygen molecule and the nitrogen molecule to become impurities can be prevented from circulating. Thus, even if the chemically unstable HFO refrigerant or the like having double bond is circulated in the refrigerant circuit, deterioration or the like of the HFO refrigerant and air due to chemical reaction or the like can be prevented. As a result, performances of the refrigerating cycle device can be ensured for a long time, and reliability can be also ensured. Also, deterioration of the refrigerant is prevented, and transportation of the heat quantity can be maintained without giving a load to the compressor 1, and energy saving can be promoted.
Also, since the air adsorbing means 3 is installed in the high-pressure liquid line through which the high-pressure liquid refrigerant flows, the influence of the pressure loss due to the air adsorbing means 3 can be reduced to an negligible level, and the efficiency of the refrigerating cycle device can be prevented from being affected. On the other hand, by installing the means 3 in the low-pressure gas line through which the low-pressure gas refrigerant flows, the low-temperature refrigerant can pass through the air adsorbing means 3, adsorbing performance is improved, and the size of the air adsorbing means 3 can be reduced in installation. Since the bypass circuit 6 is provided so that a part of the gas refrigerant passes through the air adsorbing means 3, the influence of the pressure loss of the air adsorbing means 3 in the low-pressure gas line can be suppressed.

Embodiment 2

Fig. 5 is a diagram illustrating a configuration of a refrigerating cycle device according to Embodiment 2 which describes a refrigerating cycle not part of the invention. In Fig. 5, means and the like given the same symbols as those in Fig. 1 and the like will be described supposing that the operations and the like described in Embodiment 1 are performed. Air separating / removing means 11 is means for separating the refrigerant and air using a density difference between the liquid refrigerant and air. Thus, the air separating / removing means 11 needs to be installed where the refrigerant is in the liquid state. Thus, in Fig. 5, the air separating / removing means 11 is installed in a high-pressure liquid line between the condenser 2 and the throttle device 4. Here, in each diagram which will be described in this Embodiment, it is supposed that the upper side is an upward direction in the vertical direction, and the lower side is a downward direction in the vertical direction.
Fig. 6 is a diagram illustrating a section of the air separating / removing means 11. In Fig. 6, the air separating / removing means 11 which is not part of the invention has an air vent valve 11a, an air vent pipe 11b, a container 11c, a refrigerant inflow pipe 11d, and a refrigerant outflow pipe 11e. With regard to the vertical relationship in arrangement of the air separating / removing means 11, the air vent valve 11a and the air vent pipe 11b are located on the upper side from the refrigerant inflow pipe 11d and the refrigerant outflow pipe 11e in the vertical direction.
A density of the liquid refrigerant in the HFO refrigerant is approximately 800 to 1100 [kg/m³], for example. On the other hand, the density of air is approximately 1.2 [kg/m³]. Since the air and the liquid refrigerant has a large density difference as above, the liquid refrigerant flowing in through the refrigerant inflow pipe 11d located at the lower part of the container 11c is collected as a liquid refrigerant 12b in the container 11c, and a part of the refrigerant flows out of the refrigerant outflow pipe 11e. The air flowing in together with the liquid refrigerant is collected as air 12a in the upper part of the container 11c. Also, since the refrigerant outflow pipe 11e protrudes inward from the lower part of the container 11c, even if a foreign substance heavier than the refrigerant is contained in the refrigerant for some reason, for example, it does not flow out of the refrigerant outflow pipe 11e but can be collected in the lower part of the container 11c, and removal of the foreign substance can be realized.
By opening the air vent valve 11a provided on the upper part of the container 11c, a pressure relating to inflow of the liquid refrigerant through the refrigerant inflow pipe 11d pushes out the air 12a to an external space through the air vent pipe 11b and air is purged. When the air 12a is fully pushed out, the liquid refrigerant is also pushed out, and the air vent valve 11a is closed. As mentioned above, the air remaining in the refrigerant circuit is purged.
Fig. 7 is a diagram illustrating an air conditioner not part of the invention using the air separating / removing means 11. Here, an air conditioner as a typical example of the refrigerating cycle device will be described. The air conditioner in Fig. 7 has an outdoor unit 200a and an indoor unit 200b. The outdoor unit 200a is provided with a compressor 201, a flow-passage switching valve 202, an outdoor-side heat exchanger 203, a throttle device 204, and air separating / removing means 11. On the other hand, the indoor unit 200b is provided with an indoor-side heat exchanger 205. The compressor 201 and the throttle device 204 perform operations similar to those of the compressor 1 and the throttle device 4 described above, respectively. The flow-passage switching valve 202 switches a flow of the refrigerant in the refrigerant circuit between a cooling operation and a heating operation.
The outdoor-side heat exchanger 203 functions as the condenser 2 in Embodiment 1 in the cooling operation and functions as the evaporator 5 in the heating operation to perform heat exchange between the air and the refrigerant. Also, the indoor-side heat exchanger 205 functions, to the contrary to the outdoor-side heat exchanger 203, as the evaporator 5 in the cooling operation and functions as the condenser 2 in the heating operation to perform heat exchange between the indoor air and the refrigerant. Also, though not particularly illustrated here, control means for controlling operations of each means is provided. Alternatively, a fan for performing heat exchange with the refrigerant efficiently may be provided in the outdoor-side heat exchanger 203 and the indoor-side heat exchanger 205. Then, in this air conditioner, too, as the refrigerant to be circulated in the refrigerant circuit tetrafluoropropene (tetrafluoropropylene) refrigerant, which is one type of HFO (hydrofluoroolefin) refrigerant, is used.
Subsequently, an operation of the air conditioner according to this Embodiment which is not part of the invention will be described based on the refrigerant. Arrows along the refrigerant circuit shown in Fig. 7 represent a flow of the refrigerant in the cooling operation. First, the refrigerant flow in the cooling operation will be described. The high-temperature and high-pressure gas refrigerant compressed by the compressor 201 and pressurized and discharged passes through the flow-passage switching valve 202 and is fed into the outdoor-side heat exchanger 203. The refrigerant having flown into the outdoor-side heat exchanger 203 is heat-exchanged with the air and liquefied by emitting heat to the air. The liquefied refrigerant passes through the air separating / removing means 11 and flows into the throttle device 204. The liquefied refrigerant is decompressed by passing through the throttle device 204 so as to become a gas-liquid two-phase refrigerant, flows into the indoor unit 200b through the piping and is fed into the indoor-side heat exchanger 205. The gas-liquid two-phase refrigerant having flown into the indoor-side heat exchanger 205 is heat-exchanged with the indoor air and evaporated by absorbing heat from the air and gasified. The gasified refrigerant is sucked by the compressor 201 again.
On the other hand, in the heating operation, the refrigerant flow is reversed by the flow-passage switching valve 202 so that the high-temperature and high-pressure refrigerant gas flows into the indoor unit 200b. At this time, the indoor-side heat exchanger 205 functions as the condenser, while the outdoor-side heat exchanger 203 functions as the evaporator.
Here, the air separating / removing means 11 provided in the air conditioner in Fig. 7 will be described. If the portions other than the air separating / removing means 11 are located at the highest position (position to become the uppermost part) in the outdoor unit 200a, for example, it is likely that air is also collected in that portion and does not move. Then, the air separating / removing means 11 is installed on the highest piping in the outdoor unit 200a.
Also, air-purge is most preferably performed by the air separating / removing means 11 in the cooling operation during a trial operation. The air-purge is performed in the trial operation since the earlier the air is removed, the smaller a degree of deterioration of the refrigerant can be.
Also, in the heating operation, for example, the indoor-side heat exchanger 205 becomes the condenser, and the liquid refrigerant is present in the indoor-side heat exchanger 205. Thus, if the indoor unit 200b is installed at a position higher than the outdoor unit 200a, the refrigerant and the air are separated in the indoor unit 200b, and thus, air is not collected in the air separating / removing means 11. On the other hand, if the outdoor unit 200a is installed at a position higher than the indoor unit 200b such as a roof top, by installing the air separating / removing means 11 at a position in front of the throttle device 4, for example, the air can be separated even in the heating operation. However, it is more convenient to perform air-purge in the cooling operation since the installation positions of the outdoor unit 200a and the indoor unit 200b are not to be worried about.
Figs. 8 are diagrams illustrating a case not part of the invention in which the air separating / removing means 11 is installed in the indoor unit 200b. The indoor unit 200b might be installed at a position higher than the outdoor unit 200a in many cases. Also, the trial operation might be performed in the winter in many cases. Taking such situations into consideration, as shown in Fig. 8A, the air separating / removing means 11 may be provided in the indoor unit 200b.
Also, since the indoor-side heat exchanger 205 becomes the condenser, the air separating / removing means 11 is installed on the piping where the refrigerant returns to the outdoor unit 200a. If the indoor unit 200b is located at a position higher than the outdoor unit 200a, the air separating / removing means 11 might be located below the indoor-side heat exchanger 205. Thus, as shown in Fig. 8B, the piping is raised so that it is located above the indoor-side heat exchanger 205 so that the air collected in the piping is purged by the air separating / removing means 11 configured by the air vent valve 11a and the air vent pipe 11b at the highest position. The configuration of the air separating / removing means 11 as in Fig. 8B can be configured by the outdoor unit 200a.
As mentioned above, according to the refrigerating cycle device of Embodiment 2, since the air separating / removing means 11 having the air vent valve 11a and the air vent pipe 11b is provided on the refrigerant circuit in order to remove the air remaining in the refrigerant circuit even after vacuuming from the refrigerant circuit, for example, the air to become impurities can be prevented from circulating. Thus, even if the chemically unstable HFO refrigerant or the like having double bond is circulated in the refrigerant circuit, the HFO refrigerant and the air can be prevented from deteriorating or the like by chemical reaction or the like. As a result, performances of the refrigerating cycle device can be maintained for a long time, and moreover, reliability can be ensured. Since the air separating / removing means 11 is provided in a portion through which the liquid refrigerant flows, the refrigerant and the air can be reliably separated on the basis of a difference in density between the liquid refrigerant and the air. Also, by providing the air separating / removing means 11 at the highest position in the refrigerant circuit, the air can be collected in the air separating / removing means 11 and separated efficiently.

Embodiment 3

In the above Embodiments, the cases in which the air adsorbing means 3 according to the invention and the air separating / removing means 11 which are not part of the invention are installed singularly in the refrigerant circuit (refrigerating cycle device) were shown, but the number of installation is not limited to one. Particularly, the air separating / removing means 11 may be provided at plural spots where air can be easily collected.

Embodiment 4

In the above Embodiments, the air conditioner has been described in Embodiment 2 which is not part of the invention, but not limited to that, the air conditioner provided with the air adsorbing means 3 described in Embodiment 1 according to the invention can also be realized.
According to the invention. the refrigerant containing tetrafluoropropene (CF₃CF = CH₂) has been described as the refrigerant containing chemically unstable substance.

Reference Signs List

1: compressor
2: condenser
3: air adsorbing means
3a: casing
3b: adsorbing material portion
3c: inflow pipe
3d: outflow pipe
3e, 3f: filter
4: throttle device
5: evaporator
6: bypass circuit
7: oil separator
9: capillary tube
10: oil return circuit
11: air separating / removing means
11a: air vent valve
11b: air vent pipe
11c: container
11d: refrigerant inflow pipe
11e: refrigerant outflow pipe
12a: air
12b: liquid refrigerant
100: refrigerant flow direction
200a: outdoor unit
200b: indoor unit
201: compressor
202: flow-passage switching valve
203: indoor-side heat exchanger
204: throttle device
205: indoor-side heat exchanger

Claims

A refrigerating cycle device, wherein
a compressor (1) for compressing a refrigerant containing HFO-1234yf;

a condenser (2) for condensing said refrigerant by heat exchange;

expanding means for decompressing the condensed refrigerant;

an evaporator (5) for evaporating said refrigerant by heat exchange between said decompressed refrigerant and air; and

a molecular sieve (3) adsorbing oxygen and nitrogen, are connected by piping so as to constitute a refrigerant circuit through which the refrigerant containing said HFO-1234yfis circulated

characterized in that

the molecular sieve (3) is a Zeolite having a pore size > 0.36 nm and < 0.40 nm.
The refrigerating cycle device of claim 1, wherein said molecular sieve (3) is disposed in a portion where a liquid state refrigerant with high pressure flows in said refrigerant circuit.
The refrigerating cycle device of claim 1, wherein said molecular sieve (3) is disposed in a portion where a gas state refrigerant with low pressure flows in said refrigerant circuit.
The refrigerating cycle device of claim 3, wherein a bypass circuit (6) for having a part of said refrigerant pass through the molecular sieve (3) is disposed in a portion where the gas state refrigerant with low pressure flows in said refrigerant circuit.
An air conditioner, wherein a target space is cooled/heated by the refrigerating cycle device of any one of claims 1 to 4.
Air conditioner, wherein each means constituting the refrigerating cycle device of any one of claims 1 to 5 is provided with:
a single or a plurality of indoor units (200b) each including an indoor-side heat exchanger (205) which functions as the condenser or the evaporator, the single or the plurality of indoor units (200b) performing cooling/heating of a space to be air-conditioned; and

a single or a plurality of outdoor units (200a) each including the compressor (201), the expanding means (204), and an outdoor-side heat exchanger (203) which functions as the condenser or the evaporator, the single or the plurality of outdoor units (200a) supplying a heat quantity to make the indoor unit to perform said cooling/heating by circulating said refrigerant.
The air conditioner of claim 6, wherein said outdoor unit (200a) is provided with said molecular sieve (3).
The air conditioner of claim 7, wherein said indoor unit (200b) is provided with said molecular sieve (3).