Refrigeration – Atmosphere and sorbent contacting type
Reexamination Certificate
2001-09-17
2002-11-26
Doerrler, William (Department: 3744)
Refrigeration
Atmosphere and sorbent contacting type
C062S094000, C062S093000, C062S412000
Reexamination Certificate
active
06484525
ABSTRACT:
TECHNICAL FIELD
This invention relates to an air conditioning system using an air cycle.
BACKGROUND ART
A conventional refrigerator operating through an air cycle is disclosed, for example, in “Shin-ban Reito-Kucho-Binran Dai-4-han Kiso-hen” pp.45-48, published by Japan Society of Refrigerating and Air Conditioning Engineers. Alternatively, a heating system in which an air cycle is used to form a heat pump is disclosed in “AIRAH JOURNAL” June 1997 pp.16-21, published by The Australian Institute of Refrigeration Air Conditioning and Heating. Hereinafter, this heating system will be described.
As shown in
FIG. 9
, the above heating system comprises a heat source side channel (a) and a heat application side channel (f). The heat source side channel (a) is formed by connecting a compressor (b), a first heat exchanger (c), a second heat exchanger (d) and an expander (e) in this order and arranged to operate through an air refrigeration cycle. On the other hand, the heat application side channel (f) is formed by connecting the second heat exchanger (d), a humidifier (g) and the first heat exchanger (c) in this order.
Further, in the heat source side channel (a), when the compressor (b) is driven, a room air being discharged for ventilation is taken in the compressor (b) and compressed therein. The compressed air sequentially flows through the first heat exchanger (c) and the second heat exchanger (d), is expanded in the expander (e) and is then discharged to outdoors. On the other hand, in the heat application side channel (f), an outside air being supplied to the room for ventilation is taken in and sequentially flows through the second heat exchanger (d), the humidifier (g) and the first heat exchanger (c). During this flow, the outside air is heated through heat exchange with the air of the heat source side channel (a) in both the heat exchangers (d, c) and humidified in the humidifier (g). The system provides heating for the room by heating and humidifying the outside air taken in the heat application side channel (f) and then supplying it to the room.
Problems to Be Solved
As described above, in the conventional heating system, the room air taken in the heat source side channel (a) does nothing but to sequentially flow through the compressor (b), both the heat exchangers (c, d) and the expander (e). Therefore, the following problems arise.
The actual air contains a certain amount of moisture. The air reaches a low temperature through expansion in the expander. Therefore, moisture in the air is condensed so that water droplets will be ejected together with the air from the expander. Further, when the heating system is operated as a heat pump, the temperature of the air undergoing expansion often drops to sub-zero Celsius temperatures. In this case, moisture in the air may be frozen into ice and ejected as snow combined with the air.
This problem is highlighted particularly in such a structure that supplies a room air to the compressor as in the above-described heating system. Specifically, during heating, the absolute humidity of a room air is generally higher than that of an outside air. Therefore, the air higher in absolute humidity than the outside air will be discharged from the compressor. As a result, not only moisture in the air may be condensed at the expansion, but also moisture in the air discharged from the expander may be condensed and blown out as mist.
Accordingly, the conventional heating system requires a structure for disposing of water droplets and ice discharged together with the air from the expander. Particularly, when the system has caused freezing, the processes of defrosting ice and then draining off defrosted water are needed. This creates the need for components for such processes and therefore induces the problem that the system construction is complicated.
On the contrary, if the air temperature at the inlet of the expander is elevated and the air temperature at the outlet of the expander is thereby increased, it can be prevented that moisture in the air discharged from the expander is condensed. Therefore, the above problem can be avoided. In this case, however, it is necessary to increase the input to the compressor in order to ensure a required heating capacity. This induces the problem of decreasing the COP (coefficient of performance).
If a structure is adopted which supplies an outside air to the heat exchanger in order to cool the compressed air as for example in the above-described heating system, the air temperature at the inlet of the expander may be reduced to provide improved COP because during heating the outside air is generally at a relatively low temperature. In this case, however, the air temperature at the outlet of the condenser cannot be reduced enough to avoid the above-described problem resulting from moisture condensation. Therefore, it is impossible to reduce the air temperature at the inlet of the expander to provide improved COP.
The present invention has been made in view of the foregoing points and therefore has its object of maintaining a high COP and concurrently providing a simplified construction of the system by eliminating the need for drainage and snow removal processes.
DISCLOSURE OF INVENTION
The present invention provides for dehumidifying an air, which works in an air cycle, in a portion of the cycle upstream of an expander (
22
) until the air reaches the absolute humidity of an outside air or below.
More specifically, a first solution taken in the present invention is directed to an air conditioning system that is formed with an air cycle circuit (
20
) including a compressor (
21
), a heat exchanger (
30
) and an expander (
22
) and configured to provide heating for a room by heating a secondary air through heat exchange with a primary air of the air cycle circuit (
20
) in the heat exchanger (
30
) and then supplying the heated secondary air to the room. Further, the system is provided with dehumidifying means (
55
,
60
) for dehumidifying the primary air so that the absolute humidity of the primary air is equal to or below the absolute humidity of an outside air, the dehumidifying means (
55
,
60
) being disposed in a portion of the air cycle circuit (
20
) upstream of the expander (
22
).
In a second solution taken in the present invention, based on the first solution, the primary air is an exhaust air being discharged from the room to outdoors or a mixed air of the exhaust air and an outside air and is discharged to outdoors through the expander (
22
), while the secondary air is an inlet air being supplied from outdoors to the room or a mixed air of the inlet air and a room air and is supplied to the room through the dehumidifying means (
55
,
60
).
In a third solution taken in the present invention, based on the second solution, the dehumidifying means (
55
,
60
) is arranged to supply to the secondary air moisture having been removed from the primary air.
In a fourth solution taken in the present invention, based on any one of the first to third solutions, the dehumidifying means (
55
) is disposed in a portion of the air cycle circuit (
20
) located between the compressor (
21
) and the expander (
22
) and arranged to dehumidify the primary air compressed by the compressor (
21
).
In a fifth solution taken in the present invention, based on the fourth solution, the dehumidifying means (
55
) includes a separation membrane configured so that vapor in the air is permeable from higher side to lower side in vapor partial pressure of the separation membrane, and is arranged to separate vapor from the primary air without condensation.
In a sixth solution taken in the present invention, based on the fifth solution, the separation membrane is formed of a polymer film and configured so that vapor permeates therethrough by diffusion of water molecules into the membrane.
In a seventh solution taken in the present invention, based on the fifth solution, the separation membrane has a large number of pores of substantially the same size as a free path of molecules and configured so that vapor permeates thereth
Piao Chun-cheng
Sakamoto Ryuichi
Watanabe Yuji
Yonemoto Kazuo
Yoshimi Manabu
Daikin Industries Ltd.
Doerrler William
Nixon & Peabody LLP
Shulman Mark S.
Studebaker Donald R.
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