Refrigeration – Gas controller or director – Cooled gas directed relative to cooled enclosure
Reexamination Certificate
2001-08-30
2003-03-25
Jiang, Chen-Wen (Department: 3744)
Refrigeration
Gas controller or director
Cooled gas directed relative to cooled enclosure
C062S498000
Reexamination Certificate
active
06536225
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an air-conditioning apparatus with a refrigerant circuit. This invention is directed more specifically to providing means for prevention of harmful effects due to refrigerant leakage.
BACKGROUND ART
Air-conditioning apparatus that perform a refrigerating cycle by refrigerant circulation in a refrigerant circuit have long been known. Besides, there is known another air-conditioning apparatus of the type that its every constitutional equipment such as a refrigerant circuit, a fan, and the like is housed within an outdoor casing and the outdoor casing and an indoor space are connected together by a duct for supplying conditioned-air into the room. An example of such a type of air-conditioning apparatus is an air-conditioning apparatus of the so-called roof top type. In that air-conditioning apparatus, its casing is placed on a roof of for example a house and duct connected to a room.
PROBLEMS THAT THE INVENTION INTENDS TO SOLVE
Since CFC, a substance which has been used as a refrigerant for air conditioners and refrigerators, destroys the Earth's ozone layer, there have been attempts to replace CFC refrigerants with ozone-friendly refrigerants. These CFC replacements are HFC substances such as R32, R152a, and the like. However, these substances are slightly flammable. If such a flammable substance is employed as a refrigerant for air-conditioning apparatus with an outdoor refrigerant circuit and if there occurs refrigerant leakage from the refrigerant circuit, this introduces the danger that leaking refrigerant flows into a room by way of a duct. Such refrigerant leakage may cause serious hazards. For example if leaking refrigerant is ignited in the room, this may cause a fire.
On the other hand, R407C and R410A, which are combined refrigerants containing R32, have been proposed. These combined refrigerants contain R125 which is an ignition suppressant and their flammability is lower in comparison with sole R32. However, because of the mixing of R125, the global warming potential (GWP) (the ratio with respect to CO
2
) becomes relatively high. More specifically, the GWPs of R407C, R410A, R404A, and R22 are 1530,1730, 3260, and 1500, respectively. On the other hand, since R32 and R152a have molecules that contain a relatively larger amount of hydrogen, they are easily decomposed in the atmosphere and have low GWP. Because of this, when taking into consideration the GWP, it is preferable that R32 or the like be used alone as a refrigerant.
As the aforesaid replacement for CFC, hydrocarbon refrigerants such as propane and butane have been known, but these hydrocarbon refrigerants are highly flammable. Therefore, if a refrigerant of the above flammable type is used in the foregoing air-conditioning apparatus, this may cause a fire hazard not only when the refrigerant leaks and flows into a room, but also even when the leaking refrigerant stays within the casing. That is, since these refrigerants are highly flammable, there is the danger that they are ignited by a slight spark occurring at a relay contact point in an electric system of the air-conditioning apparatus, thereby causing a fire hazard.
Further, even when a typical R22 substance or the like is used as a refrigerant, the possibility of accidents such as suffocation due to a lack of oxygen exists if leaking refrigerant flows into a room.
Bearing in mind the above-described problems, the present invention was made. Accordingly, an object of the present invention is to provide means for preventing the occurrence of harmful effects due to refrigerant leakage in air-conditioning apparatus with an outdoor refrigerant circuit.
DISCLOSURE OF THE INVENTION
In the present invention, leaking refrigerant from the refrigerant circuit is assuredly discharged into the open air.
The present invention provides a first solution means intended for an air-conditioning apparatus including a refrigerant circuit (
20
) charged with refrigerant. In this air-conditioning apparatus, a utilization side air passageway (
35
) in which a utilization side heat exchanger (
24
) for the refrigerant circuit (
20
) is disposed is divided into zones, the utilization side air passageway (
35
) being in communication with the inside of a room. In addition, an opening portion (
40
), which opens to the utilization side air passageway (
35
) to allow the utilization side air passageway (
35
) to communicate with the outside of the room so that refrigerant leaking from the refrigerant circuit (
20
) into the utilization side air passageway (
35
) is at least discharged from the opening portion (
40
) to outside the room.
The present invention provides a second solution means intended for an air-conditioning apparatus comprising an outdoor casing (
11
) for housing therein a refrigerant circuit (
20
) charged with refrigerant. In this air-conditioning apparatus, a utilization side air passageway (
35
) in which a utilization side heat exchanger (
24
) for the refrigerant circuit (
20
) is disposed and a heat source side air passageway (
31
) in which a heat source side heat exchanger (
22
) for the refrigerant circuit (
20
) is disposed are formed in the casing (
11
), these passageways (
35
) and (
31
) being in communication with the inside and the outside of a room, respectively. In addition, an opening portion (
40
) allowing the utilization side air passageway (
35
) to communicate with the outside of the casing (
11
) is formed in the casing (
11
).
The present invention provides a third solution means according to the first or second solution means in which the refrigerant of the refrigerant circuit (
20
) comprises a substance whose atmospheric specific gravity is greater than that of air and the opening portion (
40
) is so formed as to open to a lower portion of the utilization side air passageway (
35
).
The present invention provides a fourth solution means according to the third solution means wherein the opening portion (
40
) is so formed as to open to the utilization side air passageway (
35
) at a level lower than one-third of the overall height of the utilization side air passageway (
35
) from the bottom of the utilization side air passageway (
35
).
The present invention provides a fifth solution means according to the first or second solution means wherein the refrigerant of the refrigerant circuit (
20
) comprises a substance whose atmospheric specific gravity is smaller than that of air and the opening portion (
40
) is so formed as to open to an upper portion of the utilization side air passageway (
35
).
The present invention provides a sixth solution means according to the fifth solution means wherein the opening portion (
40
) is so formed as to open at a level higher than two-thirds of the overall height of the utilization side air passageway (
35
) from the bottom of the utilization side air passageway (
35
).
The present invention provides a seventh solution means according to the second solution means wherein the refrigerant of the refrigerant circuit (
20
) comprises a substance whose atmospheric specific gravity is greater than that of air, wherein an air suction opening (
38
) is formed in a lateral portion of the casing (
11
), thereby allowing the utilization side air passageway (
35
) to communicate with the inside of the room through a duct (
17
) connected to the air suction opening (
38
), and wherein the opening portion (
40
) is so formed as to open to the utilization side air passageway (
35
) at a level lower than the uppermost portion of the air suction opening (
38
).
The present invention provides an eighth solution means according to the second solution means wherein the refrigerant of the refrigerant circuit (
20
) comprises a substance whose atmospheric specific gravity is smaller than that of air, wherein an air suction opening (
38
) is formed in a lateral portion of the casing (
11
), thereby allowing the utilization side air passageway (
35
) to communicate with the inside of the room through a duct (
17
) connected to the air suction opening (
38
), and wher
Daikin Industries Ltd.
Jiang Chen-Wen
Nixon & Peabody LLP
Studebaker Donald R.
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