U.S. patent application number 12/526587 was filed with the patent office on 2010-05-06 for heat exchanger and refrigeration cycle apparatus.
This patent application is currently assigned to Mitsubishi Electric Corporation. Invention is credited to Takeyuki Maegawa, Fumio Matsuoka, Hiroyuki Morimoto, Takeshi Sugimoto, Koji Yamashita, Tetsuya Yamashita.
Application Number | 20100107681 12/526587 |
Document ID | / |
Family ID | 39788550 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100107681 |
Kind Code |
A1 |
Morimoto; Hiroyuki ; et
al. |
May 6, 2010 |
HEAT EXCHANGER AND REFRIGERATION CYCLE APPARATUS
Abstract
Heat exchangers 40, 40a, 40b for performing heat exchange
between a refrigerant and air include fins 45, 45a, 45b for heat
transfer, each of which has fine pores each having a diameter
ranging from 1 to 3.5 nm for adsorbing water contained in the air
by a capillary condensation phenomenon. Preferably, the fine pores
are distributed having a different diameter in accordance with the
position of the fins 45, 45a, 45b on the surface.
Inventors: |
Morimoto; Hiroyuki; (Tokyo,
JP) ; Sugimoto; Takeshi; (Tokyo, JP) ;
Matsuoka; Fumio; (Tokyo, JP) ; Yamashita; Koji;
(Tokyo, JP) ; Yamashita; Tetsuya; (Tokyo, JP)
; Maegawa; Takeyuki; (Tokyo, JP) |
Correspondence
Address: |
BUCHANAN, INGERSOLL & ROONEY PC
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
Mitsubishi Electric
Corporation
Chiyoda-ku
JP
|
Family ID: |
39788550 |
Appl. No.: |
12/526587 |
Filed: |
March 26, 2008 |
PCT Filed: |
March 26, 2008 |
PCT NO: |
PCT/JP2008/055665 |
371 Date: |
August 10, 2009 |
Current U.S.
Class: |
62/498 ; 165/181;
236/44C; 62/229; 62/408 |
Current CPC
Class: |
F24F 2011/0002 20130101;
F28F 13/187 20130101; F24F 13/222 20130101; F24F 11/30 20180101;
F24F 2110/20 20180101; F24F 3/14 20130101; F24F 1/0059 20130101;
F28F 17/005 20130101; F28F 1/32 20130101; F24F 1/027 20130101 |
Class at
Publication: |
62/498 ; 165/181;
236/44.C; 62/229; 62/408 |
International
Class: |
F25B 1/00 20060101
F25B001/00; F28F 1/20 20060101 F28F001/20; F24F 3/14 20060101
F24F003/14; F25B 49/02 20060101 F25B049/02; F25D 17/04 20060101
F25D017/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 28, 2007 |
JP |
2007-085385 |
Claims
1. A heat exchanger for exchanging heat between a refrigerant and
air, comprising a fin for transferring the heat, wherein the fin
includes a fine pore with a diameter ranging from 1 to 3.5 nm for
adsorbing water contained in the air by a capillary condensation
phenomenon.
2. The heat exchanger of claim 1, wherein the fine pore has a
diameter which is different in accordance with a position on a
surface of the fin.
3. The heat exchanger of claim 2, wherein the fine pores are
distributed on the fin so that each diameter becomes small as the
fine pore is positioned from an upwind to a downwind of an air flow
direction upon water adsorption.
4. The heat exchanger of claim 1, wherein the fin includes a first
fin which has the fine pore with a first predetermined diameter,
and a second fin which has the fine pore positioned either upwind
or downwind of the first fin in an air flow direction upon the
water adsorption, and has a second predetermined diameter different
from the first predetermined diameter.
5. The heat exchanger of claim 4, wherein the second fin is
positioned downwind of the first fin in an air flow direction upon
the water adsorption, and the second predetermined diameter is
smaller than the first predetermined diameter.
6. A refrigeration cycle apparatus which includes a refrigerant
circuit formed by connecting a compressor for compressing a
refrigerant, a condenser for condensing the refrigerant through a
heat exchange, a throttle device for adjusting a pressure of the
condensed refrigerant, and an evaporator for evaporating the
refrigerant through the heat exchange between the refrigerant
decompressed by the throttle device and air, further comprising the
heat exchanger of claim 1 as a heat exchanger for
dehumidification/humidification, wherein the throttle device
adjusts a refrigerant pressure for controlling adsorption and
desorption performed by the heat exchanger for
dehumidification/humidification.
7. The refrigeration cycle apparatus of claim 6, further
comprising: plural units of the heat exchangers for
dehumidification/humidification; a flow passage switching unit for
forming a flow passage through which the refrigerant selectively
flows into or out of the heat exchanger for
dehumidification/humidification; and a control unit for controlling
the flow passage switching unit to switch between the heat
exchanger for dehumidification/humidification for adsorbing water
contained in air subjected to a heat exchange in the evaporator by
flowing the refrigerant decompressed by the throttle device and the
heat exchanger for dehumidification/humidification for desorbing
the adsorbed water by flowing the refrigerant condensed by the
condenser.
8. A refrigeration cycle apparatus which includes a refrigerant
circuit formed by connecting a compressor for compressing a
refrigerant, a condenser for condensing the refrigerant through a
heat exchange, a throttle device for adjusting a pressure of the
condensed refrigerant, and an evaporator for evaporating the
refrigerant through the heat exchange between the refrigerant
decompressed by the throttle device and air, further comprising:
plural heat exchangers for dehumidification/humidification each
formed as the heat exchanger of claim 1; a flow passage switching
unit for forming a flow passage through which the refrigerant
condensed by the condenser selectively flows into the heat
exchanger for dehumidification/humidification; and a control unit
for switching between the heat exchanger for
dehumidification/humidification for adsorbing the water contained
in the air subjected to a heat exchange in the evaporator and the
heat exchanger for dehumidification/humidification for desorbing
the adsorbed water by controlling the flow passage switching unit
to flow the refrigerant.
9. The refrigeration cycle apparatus of claim 7, further comprising
a first temperature/humidity detection unit for detecting
temperature and/or humidity of the evaporator at an inlet of an air
passage of the evaporator, wherein the control unit calculates a
relative humidity of the air in the evaporator based on data
detected by the first temperature/humidity detection unit, and
controls the flow passage switching unit to switch between the heat
exchanger for dehumidification/humidification for adsorbing water
and the heat exchanger for dehumidification/humidification for
desorbing the water based on the calculated relative humidity.
10. The refrigeration cycle apparatus of claim 7, wherein the
control unit further controls a drive frequency of the compressor,
and converts the relative humidity into a dew point to control the
drive frequency of the compressor and switching of the heat
exchanger for dehumidification/humidification under the control of
the flow passage switching unit so that the evaporating temperature
of the refrigerant in the evaporator is equal to or higher than the
dew point.
11. The refrigeration cycle apparatus of claim 7, further
comprising a second temperature/humidity detection unit for
detecting the temperature and/or the humidity of the heat exchanger
for dehumidification/humidification at an inlet of the air passage
of the heat exchanger for dehumidification/humidification, wherein
the control unit calculates the relative humidity of the air in the
heat exchanger for dehumidification/humidification based on the
detection data of the second temperature/humidity detection unit to
convert the calculated relative humidity into a dew point, and
controls the drive frequency of the compressor and switching of the
heat exchanger for dehumidification/humidification under the
control of the flow passage switching unit so that a temperature of
a refrigerant which passes in the heat exchanger becomes higher or
equal to the dew point.
12. The refrigeration cycle apparatus of claim 7, further
comprising an air passage switching unit for switching the air
passages between the plural heat exchangers for
dehumidification/humidification and the evaporator, wherein the
control unit controls the air passage switching unit to form the
air passages for the heat exchanger for adsorbing water and the
evaporator.
13. The refrigeration cycle apparatus of claim 8, further
comprising a first temperature/humidity detection unit for
detecting temperature and/or humidity of the evaporator at an inlet
of an air passage of the evaporator, wherein the control unit
calculates a relative humidity of the air in the evaporator based
on data detected by the first temperature/humidity detection unit,
and controls the flow passage switching unit to switch between the
heat exchanger for dehumidification/humidification for adsorbing
water and the heat exchanger for dehumidification/humidification
for desorbing the water based on the calculated relative humidity
by controlling the flow passage switching unit.
14. The refrigeration cycle apparatus of claim 8, further
comprising a second temperature/humidity detection unit for
detecting the temperature and/or the humidity of the heat exchanger
for dehumidification/humidification at an inlet of the air passage
of the heat exchanger for dehumidification/humidification, wherein
the control unit calculates the relative humidity of the air in the
heat exchanger for dehumidification/humidification based on the
detection data of the second temperature/humidity detection unit to
convert the calculated relative humidity into a dew point, and
controls the drive frequency of the compressor and switching of the
heat exchanger for dehumidification/humidification under the
control of the flow passage switching unit.
15. The refrigeration cycle apparatus of claim 9, further
comprising a second temperature/humidity detection unit for
detecting the temperature and/or the humidity of the heat exchanger
for dehumidification/humidification at an inlet of the air passage
of the heat exchanger for dehumidification/humidification, wherein
the control unit calculates the relative humidity of the air in the
heat exchanger for dehumidification/humidification based on the
detection data of the second temperature/humidity detection unit to
convert the calculated relative humidity into a dew point, and
controls the drive frequency of the compressor and switching of the
heat exchanger for dehumidification/humidification under the
control of the flow passage switching unit.
16. The refrigeration cycle apparatus of claim 10, further
comprising a second temperature/humidity detection unit for
detecting the temperature and/or the humidity of the heat exchanger
for dehumidification/humidification at an inlet of the air passage
of the heat exchanger for dehumidification/humidification, wherein
the control unit calculates the relative humidity of the air in the
heat exchanger for dehumidification/humidification based on the
detection data of the second temperature/humidity detection unit to
convert the calculated relative humidity into a dew point, and
controls the drive frequency of the compressor and switching of the
heat exchanger for dehumidification/humidification under the
control of the flow passage switching unit.
17. The refrigeration cycle apparatus of claim 8, further
comprising an air passage switching unit for switching the air
passages between the plural heat exchangers for
dehumidification/humidification and the evaporator, wherein the
control unit controls the air passage switching unit to form the
air passages for the heat exchanger for adsorbing water and the
evaporator.
18. The refrigeration cycle apparatus of claim 9, further
comprising an air passage switching unit for switching the air
passages between the plural heat exchangers for
dehumidification/humidification and the evaporator, wherein the
control unit controls the air passage switching unit to form the
air passages for the heat exchanger for adsorbing water and the
evaporator.
19. The refrigeration cycle apparatus of claim 10, further
comprising an air passage switching unit for switching the air
passages between the plural heat exchangers for
dehumidification/humidification and the evaporator, wherein the
control unit controls the air passage switching unit to form the
air passages for the heat exchanger for adsorbing water and the
evaporator.
Description
TECHNICAL FIELD
[0001] The present invention relates to a heat exchanger for
adsorbing water content in the air, and a refrigeration cycle
apparatus having the same.
BACKGROUND ART
[0002] In a refrigeration cycle apparatus using a refrigeration
cycle such as an air conditioning system and a refrigeration
system, a compressor, a condenser (heat exchanger), an expansion
valve, and an evaporator (heat exchanger) are basically connected
with the pipe to form a refrigerant circuit for circulating a
refrigerant such as a geotropic refrigerant mixture, a pseudo
azeotropic refrigerant mixture, and a single refrigerant. Utilizing
that the refrigerant absorbs and radiates heat against air
subjected to the heat exchange upon evaporation and condensation,
the air-conditioning and cooling operations are performed while
changing the pressure of the refrigerant passing through a
pipe.
[0003] The heat exchanger functioning as the evaporator and the
condenser allows the refrigerant to pass through the pipe therein
to perform heat exchange. Since in the heat exchanger serving as
the evaporator, the low temperature refrigerant passes through the
pipe to absorb the heat in the air, the water content (vapor) in
the air is condensed on the surface of the pipe to be deposited
thereon as frost. When the frost is deposited (formed), the frost
exists between the refrigerant and air. The deposited frost narrows
a gap through which air passes, thus interfering with the air flow.
Heat exchange between the refrigerant and air cannot be
appropriately performed, thus deteriorating operation efficiency.
Therefore, defrosting for removing the frost adhered to the
evaporator is performed on a regular basis, or when it is judged
that efficiency is deteriorated.
[0004] The defrosting may remove the frost adhered to the
evaporator, but consumes an extra energy, thus failing to improve
the efficiency of the air conditioning system. Immediately after
finishing the defrosting, the temperature in the freezer and
refrigerator is increased although it is required to maintain a
predetermined temperature range. In such a case, the load for
cooling up to a required temperature range is increased, thus
further consuming electric power, resulting in efficiency
deterioration.
[0005] Meanwhile, in the case of such as an air conditioning system
for cooling/heating, in the in-between period of cooling (rainy
season, autumn) for example, a cooling load tends to be small. In
such a case, an operation frequency of the compressor is usually
controlled to decrease the flow rate of the refrigerant (per unit
time) circulated in the refrigerant circuit. At this time, the
evaporating temperature in the evaporator increases to remove a
sensible heat. However, a latent heat (water content in the air
(vapor)) may not be removed. If the latent heat in the room cannot
be removed, the relative humidity in the air in the room will be
increased, which cause discomfort of the person in the room to
increase.
[0006] A device for removing the water content in the air has been
disclosed to solve the aforementioned problem (for example, see
Patent Document 1). The dehumidifying device uses zeolite which is
a porous inorganic oxide, as a water adsorbing material
(hereinafter referred to as an adsorbing material) for example, to
make the fin for performing heat exchange between the air and
refrigerant support it.
[0007] [Patent Document 1] Japanese Unexamined Patent Application
Publication No. 2004-353887 (FIG. 1)
DISCLOSURE OF INVENTION
Problems to be Solved by the Invention
[0008] In the aforementioned device, the thermal expansion may
cause distortion between the fan and the adsorbing material, so
that the adsorbing material may peel off to be contained in the air
and dispersed. In the case where such device is employed in the
freezer and refrigerator for storing foods, it is required to
prevent the adsorbing material from being peeled off for quality
control of foods. The aforementioned requirement may be applied to
the heat exchanger for air conditioning in the living space. It is
therefore difficult to control the heat exchanger using the
adsorbing material. The loss in thermal conduction may lower the
energy efficiency.
[0009] If the zeolite is employed as the adsorbing material on the
surface of the desiccant rotor for removing a water content in the
air which flows into the heat exchanger, the temperature required
for desorption is high. Therefore, it is difficult to desorb the
adsorbed water using the temperature of the refrigerant flowing
through the refrigerant circuit and to re-use the water.
[0010] The present invention is made to solve the aforementioned
problem, and an object of the present invention is to provide a
heat exchanger and a refrigeration cycle apparatus such as an air
conditioning device and refrigerator capable of more efficiently
adsorbing water performing the heat exchange.
Means for Solving the Problems
[0011] A heat exchanger according to the present invention includes
fins for heat transfer in the heat exchanger for exchanging heat
between a refrigerant and air. The fin has fin pores on the surface
for adsorbing the water in the air by capillary condensation. Each
of the fine pores has a different diameter depending on the
position on the surface of the fins.
[0012] Preferably the fine pores are in the range from 1 to 20 nm.
The fin is made of a material which contains aluminum, titanium,
zirconium, niobium, or tantalum. The fine pores are formed by an
anodic oxidation method. After forming recess portions at
predetermined intervals on the material to be the fin, fin pores
can be formed by the anodic oxidation method.
Advantages
[0013] The fine pores are formed on the surface of the fin of the
heat exchanger such that the fin itself functions as the water
adsorbing unit using the capillary condensation phenomenon. The
heat exchanger capable of making the fins adsorb water contained in
air in the subject space may be provided without requiring special
means and materials. The peeling-off of the supported adsorbing
member never occurs, thus it is safe from the viewpoint of
sanitation and easy to manage. No pressure loss of air caused by
the adsorbing material occurs, so that efficient heat exchange can
be performed in view of the energy consumption. Since it is not
necessary to provide adsorbing material, the apparatus can be made
compact. By making each diameter of the fine pores different
depending on the position on the fin surface, it is possible to
obtain the heat exchanger appropriately performing
adsorption/desorption while being suitably adapted to the
environment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a configuration view showing an essential portion
of the structure of a heat exchanger according to Example 1.
[0015] FIG. 2a is a view showing a relationship between the fine
pore diameter of the fin which forms the heat exchanger and the
relative humidity.
[0016] FIG. 2b is a view schematically showing how the water being
adsorbed in the fine pore.
[0017] FIG. 3 is a view showing characteristics of the fine pore
diameter and adsorption.
[0018] FIG. 4 is a view showing an example of the water adsorbing
characteristics of the fine pores on the surface of a fin 45.
[0019] FIG. 5 is an enlarged view of the surface of the fin 45.
[0020] FIG. 6 is a structural view showing the heat exchanger
having a fine-pores distribution of along an air flow direction
(column direction).
[0021] FIG. 7a is a view showing the relationship between the air
flow direction (column direction) and the relative humidity.
[0022] FIG. 7b is a view showing the relationship between the air
flow direction and the adsorption amount.
[0023] FIG. 8a is a view showing the relationship between the air
flow direction (column direction) and the relative humidity.
[0024] FIG. 8b is a view showing the relationship between the air
flow direction and the desorption amount.
[0025] FIG. 9a is a view showing the method for manufacturing the
fin having fine pores with the same diameter.
[0026] FIG. 9b is a view showing the method for manufacturing the
fin having fine pores with a different diameter.
[0027] FIG. 10 shows operation points on the psychrometric
diagram.
[0028] FIG. 11 schematically shows an exemplary structure of a
refrigeration cycle apparatus according to Embodiment 4.
[0029] FIG. 12 is a relationship view showing a relationship
between the evaporating temperature and COP.
[0030] FIG. 13 is a schematic view showing an exemplary structure
of the refrigeration cycle apparatus according to Embodiment 5.
[0031] FIG. 14 is a schematic view three-dimensionally showing a
humidifying unit of the refrigeration cycle apparatus.
[0032] FIG. 15 is an illustrative view showing the state where an
air passage in an indoor unit is switched.
[0033] FIG. 16 is a P-h diagram showing the state of the
refrigerant in the refrigeration cycle.
[0034] FIG. 17 is a psychrometric diagram for explaining the
operation of the refrigeration cycle apparatus.
[0035] FIG. 18 is a schematic view showing an exemplary structure
of the refrigeration cycle apparatus according to Embodiment 6.
[0036] FIG. 19 is a schematic view showing the structure of the
indoor unit having a built-in evaporator.
[0037] FIG. 20 is an illustrative view showing the state where the
air passage in the indoor unit is switched.
[0038] FIG. 21 is a P-h diagram showing the state of the
refrigerant in the refrigeration cycle.
[0039] FIG. 22 is a psychrometric diagram for explaining the
operation of the refrigeration cycle apparatus.
[0040] FIG. 23 is a schematic view showing an exemplary structure
of the refrigeration cycle apparatus according to Embodiment 7.
REFERENCE NUMERALS
[0041] 1, 1a, 1b, 1c, 1d refrigerant pipe [0042] 2, 2a, 3, 3a
bypass pipe [0043] 10 compressor [0044] 20 condenser [0045] 30, 31,
32, 33, 34, 35, 36, 37 on-off valve [0046] 38, 39 three-way valve
[0047] 40 heat exchanger [0048] 40a heat exchanger with distributed
fine pores [0049] 41, 41a, 41b, 41c, 41d, 41e, 41f heat exchanger
for dehumidification/humidification [0050] 45 fin [0051] 45a fine
pores [0052] 45b porous layer [0053] 45c barrier layer [0054] 45aa
fin at the first column [0055] 45ab fin at the second column [0056]
45ac fin at the third column [0057] 46 heat transfer pipe [0058]
50,51 back-flow prevention member [0059] 60, 61, 62, 63, 64, 85
throttle device [0060] 70 evaporator [0061] 80, 80a, 80b control
unit [0062] 81 temperature/humidity detection unit [0063] 90,91
blower [0064] 100, 100a, 100b, 100c refrigeration cycle apparatus
[0065] 300,300a indoor unit [0066] 301a, 301b, 302a, 302b, 303a,
303b, 304a, 304b, 311a, 311b, 312a, 312b, 313a, 313b, 314a, 314b
air passage switching unit [0067] 305a, 305b, 315a, 315b air
passage switching unit [0068] 400 refrigerated warehouse [0069] 401
interior [0070] 500 external air [0071] 610 dc power source [0072]
620 electrolyte [0073] 630 electrolyte vessel [0074] 640 carbon
electrode [0075] 650 fin
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1
[0076] FIG. 1 shows an essential portion of a heat exchanger 40
according to Embodiment 1 of the present invention. The structure
of the heat exchanger 40 as the featuring part of the present
invention will be described referring to FIG. 1. The heat exchanger
of a fin tube type which has been widely used for the refrigerator
and air conditioning system will be explained as an example.
[0077] The heat exchanger 40 is mainly composed of plural fins 45
for heat exchanger (hereinafter referred to as a fin 45), and
plural heat transfer pipes 46. The fin 45 of the present embodiment
is a flat plate made of the material with a high thermal
conductivity (thermal conductivity: approximately 230 W/mK) such as
aluminum. The fin 45 has fine pores on the surface as described
later. The plural fins 45 are laminated at a predetermined
interval. The heat transfer pipes 46 are provided, for example, at
a predetermined interval so as to penetrate through holes formed in
each fin 45. Each heat transfer pipe 46 becomes part of a
refrigerant circuit, allowing the refrigerant to flow therethrough.
The heat of the refrigerant flowing through the heat transfer pipe
46 and the heat of the air flowing outside are transferred via the
fins 45 to expand the heat transfer area, thus the heat exchange
between the refrigerant and the air is efficiently performed. The
path of the heat transfer pipes 46 in the heat exchanger 40 is not
especially limited. For example, the flow path may be formed to be
branched to allow the refrigerant to flow into the plural heat
transfer pipes 46 which penetrate the fins 45, and then to be
joined. The refrigerant flow path may also be formed to make the
laminated fins 45 bent at the end of the heat exchanger 40 or
connected by the bent pipe reciprocated. Referring to FIG. 1, the
heat transfer pipes 46 penetrate the fins 45 at 6 points, however,
the number of the heat transfer pipes 46 is not limited
thereto.
[0078] The fin 45 is made of materials containing aluminum,
titanium, zirconium, niobium, or tantalum, and includes a plurality
of fine pores having diameters ranging from 1 to 20 nm. The fine
pores of the fin 45 may be formed by the anodic oxidation method.
The fine pores may be formed by the anodic oxidation method after
forming recesses at a predetermined interval in the material for
forming the fin 45 in advance.
[0079] FIG. 2a is a view showing the relationship between the
diameter (hereinafter referred to as fine pore diameter) of the
fine pores of the fin 45 and the relative humidity at which the
capillary condensation occurs. The horizontal axis represents the
fine pore diameter [nm (nanometer)], and the vertical axis
represents the relative humidity [%] of the air in the subject
space (assuming that current humidity is P, and saturated humidity
at the current humidity being PO, the relative humidity may be
expressed as P/PO). FIG. 2a shows a graph calculated based on the
formula of Kelvin.
Relative humidit y : P P 0 = exp ( - 2 v 1 .gamma.cos .theta. rRT )
[ Formula 1 ] ##EQU00001##
[0080] Here, v1 denotes a condensed molecule volume, .gamma. a
surface tension, .theta. an angle when in contact with capillary, R
a gas constant (8.31[J/mol.degree. K]), T the absolute temperature,
and r the radius of the fine pore. The relationship may hold in the
case of water vapor. So, the radius r of the fine pore required for
water vapor to cause capillary condensation may be theoretically
obtained for a certain relative humidity P/PO.
[0081] As shown in FIG. 2a, capillary condensation (a phenomenon in
which the vapor (water content) inside the fine pore is liquefied)
occurs at the relative humidity corresponding to the fine pore
diameter. In FIG. 2a, water molecules may be maintained in the fine
pore in the zone A, while water molecules cannot be maintained in
the fine pore in the zone B. That is, the water content in the air
may be adsorbed in the zone A. On the contrary, the water content
can be removed from the fine pore by making the air conditions of
the zone B.
[0082] FIG. 2b shows the image of adsorption of water into the fine
pore. As shown in FIG. 2b, water is gradually adsorbed into the
fine pore. The equilibrium adsorption amount may be sharply
increased (changed) at the boundary of the predetermined narrow
range in the vicinity of the relative humidity when a number of
fine pores having the diameter in accordance with the relative
humidity uniformly are formed.
[0083] The relationship between the fine pore diameter and the
adsorption isothermal may be obtained in reference to FIG. 2a. FIG.
3 is a characteristic view showing the relationship between the
water content (adsorbing characteristics) of the fine pore diameter
of the fin 45 according to Embodiment 1 of the present invention
and the relative humidity showing a sharp change (hereinafter
referred to as rising edge). As shown in FIG. 3, the relative
humidity at the rising edge becomes relatively low by making the
fine pore diameter of the fin 45 relatively small (line (a) in FIG.
3). On the other hand, the relative humidity at the rising edge
becomes relatively high by making the fine pore diameter large
(line (b) in FIG. 3).
[0084] For example, the adsorbing material may demonstrate the
rising edge feature at the relative humidity of approximately 30%
as shown by the line (c) in FIG. 3 by setting the fine pore
diameter d at 2.0 nm. The adsorbing material may demonstrate the
sharp rising edge feature at the relative humidity of approximately
90% by setting the fine pore diameter of 20 nm. Adsorbing
characteristics of the fin 45 may be freely controlled using FIG.
3.
[0085] Since the adsorbing material is used for the fin 45 for the
purpose of dehumidification, an upper limit of the relative
humidity is less than 100%. The line (b) shown in FIG. 3 indicating
a sharp rising edge at the relative humidity of approximately 90%
is an upper limit value of the adsorbing characteristics, and the
fine pore diameter is approximately 20 nm. Therefore, when used for
the air-conditioning device (including the refrigerator), the upper
limit of the fine pore diameter of the fin 45 is set at 20 nm.
[0086] In the manufacturing, selection of the fine pore diameter in
accordance with the usage may reduce the production volume to
increase the cost of the adsorbing material. Since the fine pore of
nano scale is invisible to human eyes, it is not possible to
identify the fin with a different fine pore diameter. As a result,
there may be a risk of mounting the adsorbing material with
improper fine pore diameter on the product, resulting in a poor
quality. Therefore, it is preferable to consolidate the fine pore
diameter of the adsorbing material to one kind in view of the cost
and quality. However, in order to be effective as the fin 45 for
dehumidification, the fine pore diameter have to be consolidated
into a fine pore diameter capable of dehumidification in the most
usages (most humidity conditions).
[0087] Table 1 shows an example of the fine pore diameters
(relative humidity) required for the respective usages. Table 1
shows the relative humidity in the subject space and the fine pore
diameter of the fin 45 required for the relative humidity. Table 1
is quoted from the collection of papers of "Latest humidity control
technology" in the lecture meeting of Japan Society of
Refrigerating and Air conditioning Engineers (pp. 5-6, published on
May 25, 2005).
TABLE-US-00001 TABLE 1 Fine pore Relative humidity Field diameter
[nm] condition [%] Fruits and vegetables 6-20 70-95 Stock farm
products 4-20 65-95 Pharmaceutical factory 2-4 40-50 Library 2-4
40-50 Art museum/museum 2-5 40-55 Photographic plant 1-6 24-70
Human 1-2 20-30
[0088] For example, in the warehouse for storing fruits and
vegetables, the relative humidity is required to be in the range
from approximately 70 to 95%, therefore, the fine pore diameter may
be set so that the relative humidity sharply rises at approximately
70 to 95% in the adsorbing characteristics shown in FIG. 2a. That
is, the fine pore diameter of the adsorbing material may be
designed to be 6 to 20 nm in reference to FIG. 2a (showing the
relationship between the fine pore diameter and capillary
phenomenon). In an air conditioned space (living space for the
human), the relative humidity is generally said to be kept in the
range from 20 to 30% or higher.
[0089] Generally, the lower limit value of the relative humidity is
considered to be in the range from approximately 20 to 30% except
for a special usage. Accordingly, the use of the fin 45 with the
adsorbing characteristics (the fine pore diameter is in the range
from approximately 1.0 nm to 3.5 nm) which sharply rises at the
relative humidity around 20% to 50% as shown in FIG. 3 may cover
almost all the usage (wide range). Increase of the use of the fin
45 having the same specification (the same fine pore diameter) may
produce a mass production effect to reduce the cost of the fin 45,
thus improving the manufacturing quality.
[0090] The refrigeration cycle of the refrigerator is designed to
have the condensation pressure corresponding to the condensation
temperature of approximately 65.degree. C. Because of the
restriction, in the condenser, the air of an external air side 100a
is heated up to about 65.degree. C. So that, it is realistic to
think that a lower limit value of the relative humidity produced by
the exhaust heat of the condenser of the refrigeration cycle be
approximately 10% (an external air of 32.degree. C. and the
relative humidity 60% is heated up to 65.degree. C. and the
relative humidity 10%). The fine pore diameter at that time is
approximately 1 nm by FIG. 2a. Accordingly, the lower limit of the
fine pore diameter of the fin 45 for dehumidification is made to be
1 nm.
[0091] FIG. 4 is a view showing an example of the water adsorbing
characteristics of the fine pore formed on the surface of the fin
45. Next, the fine pore formed on the surface of the fin 45 will be
described. FIG. 4 shows the adsorption isothermal of the fine pore
with the diameter of approximately 2 nm. The horizontal axis
represents the relative humidity [%] of the air in the space to be
cooled, and vertical axis represents the water content (adsorbed
water amount/weight of fin 45, which is proportional to the
equilibrium adsorption amount).
[0092] As shown in FIG. 4, the fin 45 capable of adsorbing water at
the relative humidity of approximately 30% or higher no longer
keeps adsorbing the water when the relative humidity is decreased
to approximately 30% or lower. Therefore, the adsorbed water may be
desorbed by lowering the relative humidity to approximately 30% or
smaller.
[0093] FIG. 5 is an enlarged view of the surface of the fin 45. In
the present embodiment, as described above, the fine pores 45a for
adsorbing/desorbing the water are formed on both surfaces of the
fin 45 simultaneously using the anodic oxidation (anodization).
When performing a direct current electrolysis under the environment
of in the acidic solution such as sulfuric acid, oxalic acid,
phosphoric acid, chromic acid, and alkaline solution such as sodium
phosphate with the fin (aluminum) being an anode, the aluminum ion
(Al.sup.3+) dissolved from the fin (aluminum) reacts with the water
(H.sub.2O) to generate an aluminum oxide (alumina) film
(hereinafter, referred to as the anodic oxide film) on the
aluminum, which is a substrate metal. Here, the fine pore 45a may
be formed by a through hole, because an effect remains unchanged
that the fine pore 45a can adsorb/desorb water even if it is a
through hole.
[0094] The anodic oxide film is formed of a porous layer 45b where
the vertical fine pore 45a is formed and a barrier layer 45c at the
bottom wall portion in contact with the substrate metal, having a
so-called hexagonal cell structure. When forming the fine pore 45a,
since the thickness of the barrier layer 45c is basically kept
constant, the depth of the fine pore 45a may be controlled by
substantially controlling the film thickness. Since the film
forming rate and film thickness depend on the current or potential
to be supplied between the both electrodes and the anodic oxidation
period, the current or potential to be supplied between the both
electrodes and the anodic oxidation period are controlled when
forming the fine pore 45a with a predetermined depth. Since the
number of fine pores per unit area (density) and the fine pore
diameter depend on the potential between the both electrodes, the
potential therebetween is controlled so as to form a predetermined
number and diameter of the fine pores. A mold (metal mold) having
protrusions formed at an interval corresponding to that of the fine
pores 45a is pressed against an aluminum surface, which is to be a
fin 45, to form regular recess portions on the surface. Thereafter,
when the anodic oxidation is conducted, the fine pores 45a are
formed centering around the recess portion, so that the fine pores
45a are regularly arranged and it is possible to perform high
accuracy control on a surface with a constant density. In order to
prevent the fine pore 45a formed by the anodic oxidation from
reacting with the water contained in air to be blocked, the fin 45
is heated by hot air at the temperature 100 to 200.degree. C.
immediately after the formation of the fine pores to remove the
water contained in the film to perform an operation of changing
into a stable oxide. The heat transfer pipes 46 are inserted into
the thus formed plural through holes of the fins 45 to make the
heat exchanger 40.
[0095] In Embodiment 1, the fine pores are formed on the surface of
the fin 45 of the heat exchanger 40 and the fin 45 is made to
function as water adsorbing member, so that it is possible to make
the water in the air in the subject space adsorb without requiring
the special member and materials. Thus, the adsorbing material can
be prevented from peeling off due to the distortion caused by the
temperature swing between adsorbing materials having different heat
expansion coefficients. Since no thermal resistance exists between
the fin 45 and the adsorbing material such as silica gel, the heat
transfer efficiency may be improved. The thermal conductivity of
the silica gel is small, such as approximately in the range from
0.05 to 0.17 W/mK, so that the heat transfer efficiency may be
deteriorated. However, since direct heat exchange can be performed
between the fin 45 with good thermal conductivity and the air, the
heat exchange between the air and the refrigerant can be more
efficiently conducted.
[0096] The fin 45 does not have to be thick to accommodate the
adsorbing material so that the interval between the fins 45 of the
heat exchanger 40 may be increased. As a result, the pressure loss
of the flowing air is reduced, so that the input of the fan for
making the air flow into the heat exchanger 40 can be decreased.
Even if the interval is not changed, the heat exchanger 40 may be
made compact by the amount corresponding to the thickness of the
adsorbing material. Since the fine pores with a fine pore diameter
within the range from approximately 1 to 20 nm in accordance with
the relative humidity are arranged to be formed on the surface of
the fin 45, the adsorbed water may be desorbed and reproduced
(making the water adsorbed again) using the heat (exhaust heat) of
the refrigerant flowing in a common refrigeration cycle
apparatus.
[0097] The fine pores having a regular pattern are formed by the
anodic oxidation method vertically to the surface of the fin 45.
Therefore, unlike the adsorbing material with the fine pores
arranged in no regular pattern, for example, the flow
directionality of the adsorbed water may be aligned to efficiently
transfer the heat of the fin 45.
Example 2
[0098] FIG. 6 is a configuration view showing an essential portion
of a heat exchanger 40a according to Embodiment 2 of the present
invention. In FIG. 6, fins 45aa, 45ab, 45ac are made to have fine
pores with different diameters for each column along the air flow
direction. That is, against the air flow direction upon the
adsorption, the fine pore diameter at an upwind side is made large,
and that at a downwind side is made small. Therefore, in the case
of FIG. 6, the fine pores are distributed in such an aspect that
fine pore diameter on the first column 45aa>fine pore diameter
on the second column 45ab>fine pore diameter on the third column
45ac.
[0099] FIG. 7a shows a simulated result of the relative humidity
distribution of the air flow direction (column direction of the
heat transfer pipe) of the heat exchanger using fins having the
same fine pore diameter. The water content of the fin 45 has a
feature to rise up at the relative humidity of approximately 30%.
From the heat transfer pipe at the upwind side upon the adsorption,
it is referred to as the first and the second, and the third
columns. As can be understood from FIG. 7a, as the air flows from
the upwind side to the downwind side, the water is adsorbed by the
fin 45, so that the relative humidity around the fin is
decreased.
[0100] Meanwhile, the embodiment according to the present invention
employs the fin which has the fine pore distribution with different
fine pore diameters along the flow direction. That is, viewing from
the upwind side, the fine pore diameter on the second column is
smaller than that on the first column, and the fine pore diameter
on the third column is smaller than that on the second column. The
fine pore diameters of the fin 45 is changed for each column. The
number of the columns is not especially limited, though, as the
number of the columns is increased, the diameter of the fine pores
distributed on the fin may be gradually changed.
[0101] For example, the fin 45aa on the first column has the fine
pores diameter for which the water content rises at the relative
humidity of approximately 50% (3.5 nm), the fin 45ab on the second
column at the relative humidity of approximately 40% (2.5 nm), and
the fin 45ac on the third column at the relative humidity of
approximately 30% (2 nm). The change in the adsorption amount with
respect to the air flow direction (column direction) is shown in
FIG. 7b. As can be understood from FIG. 7b, the total adsorption
amount of the fin with the fine pores made to have a distribution
along the column direction is larger than that of the fin having
the same fine pores diameter. So that the fin may be effectively
used.
[0102] In the case of the fin having the same fine pores diameter,
the more downstream side the fin is located, the smaller the
difference becomes between the relative humidity of air around the
fin and the relative humidity 30%, where the water content of the
fin rises. So that the adsorbing speed of the fin is reduced, and
resultantly, the adsorption amount decreases toward the downstream
side.
[0103] The fin having the fine pores of relatively larger diameter
may be employed, so that it is possible to reduce the total cost of
the fin. (the larger the fine pore diameter becomes, the less
manufacturing period, and accordingly, the production cost may be
reduced).
[0104] FIG. 8a shows the relative humidity to the air flow
direction upon desorption when using the fin with fine pores having
the same diameter. The air flow direction is reversed to that upon
adsorption. While on desorption, the fin at the third column is at
the upwind side, on adsorption it is at the downwind side. From
FIG. 8a, it is found that the relative humidity around the fin
becomes larger toward the downwind side.
[0105] The embodiment according to the present invention employs
the fins having a fine pore distribution making the fine pore
diameter changed along the flow direction. For example, the fin
45aa on the first column has the fine pore diameter for which the
water content rises at the relative humidity of approximately 50%
(about 3.5 nm), the fin 45ab on the second column the relative
humidity of approximately 40% (about 2.5 nm), and the fin 45ac on
the third column the relative humidity of approximately 30% (about
2 nm), respectively. As shown in FIG. 8b, the fine pore
distribution in the column direction provides a larger desorption
amount in total compared with the use of the fin having the fine
pores of the same diameter, resulting in the effective use of the
fin. In the case of the fins having the fine pores of the same
diameter, the difference between the relative humidity of air
around the fin and the relative humidity 30%, where the water
content around the fin 45 rises, becomes smaller toward the
downstream side to decelerate adsorbing rate of the fin, an
desorption amount is decreased toward the downwind side.
[0106] The distribution of the fine pores diameter of the fin 45
formed along the column direction allows effective use of the fin
45 to improve the adsorption/desorption performance. Resultantly,
it is possible to make the heat exchanger compact.
[0107] When the fin includes two columns (FIG. 1 shows two columns,
however, three or more columns may be possible) as shown in FIG. 1,
the relative humidity is lowered at the downwind side, it is
preferable to set the fine pore diameter to be relatively smaller.
As shown in FIG. 7a, the relative humidity around the fin adjacent
to the outlet is approximately 35%. The fine pore diameter may be
set to approximately 1 to 3.5 nm because the fin is required to
have characteristics in which the water content abruptly rises at
the relative humidity of about 20 to 40%.
[0108] In the description, the fine pore diameter of the fin at the
downwind side with respect to the air flow direction in the water
absorption is smaller than the fine pore diameter of the fin at the
upwind side. However, the fine pore diameter of the fin at the
downwind side with respect to the air flow direction in the water
absorption may be larger than that of the fin at the more downwind
side than that so far as the fine pore diameters are different for
each column and in the range approximately from 1 to 3.5 nm. For
example, when the fine pore diameter of the fin outside the heat
exchanger may be set to be larger than the fine pore diameter of
the fin inside the heat exchanger, it is possible to perform
efficient dehumidification by making the air in contact with the
heat exchanger flow from two directions rather than a single
direction.
[0109] A method for manufacturing the heat exchanger having a fine
pore distribution using an anodic oxidation method will be briefly
described. As shown in FIG. 9a, a three-column fin 650 is
collectively submerged in an electrolysis vessel 630 to form a fin
having homogeneous fine pores. Meanwhile, each column of the fin
650 is submerged to form predetermined fine pores as shown in FIG.
9b when manufacturing the heat exchanger having fine pore
distribution along the column direction. The anodic oxidation is
conducted three times under the different conditions to produce
three fins having different fine pores. Thereafter, the heat
transfer pipes 43 are inserted for each column to be finally
combined together by connecting a U-type pipe for providing the
three-column heat exchanger. In FIGS. 9(a) and 9(b), reference
numerals 610, 620 and 640 denote a direct current power supply, an
electrolyte, and a cathode, respectively.
[0110] The effect derived from operating the heat exchangers 40,
40a using the fins with fine pores while being cooled with the
refrigerant supplied thereto will be described. FIG. 10 shows
operations on the psychrometric diagram when the refrigerant is
supplied to the heat exchanger and when the refrigerant is not
supplied. At the inlet of the heat exchangers 40 and 40a, the
dry-bulb temperature, the relative humidity, the absolute humidity,
and the dew point of air are 25.degree. C., 60%, 0.0119[kg/kg], and
16.7.degree. C., respectively. In the case where the refrigerant is
not supplied, the relative humidity is lowered while the air
temperature is increased by the adsorbing heat to finally become
the air of the state (b)(dry-bulb temperature: 32.2.degree. C.,
relative humidity: 30%, absolute humidity: 0.0119 kg/kg, and dew
point: 12.44.degree. C.). Meanwhile, in the case where the heat
exchanger 40 is operated while cooling with the refrigerant
supplied thereto, the refrigerant removes the adsorbing heat to
substantially realize isothermal adsorption to finally become the
state (c) (dry-bulb temperature: 25.degree. C., relative humidity:
30%, absolute humidity: 0.0058 kg/kg, and dew point: 6.24.degree.
C.)
[0111] The difference in the absolute humidity for the case where
the refrigerant is supplied and the case where the refrigerant is
not supplied shows that the absolute humidity difference in the
case where the refrigerant is supplied is twice higher than the
absolute humidity difference in the case where the refrigerant is
not supplied (absolute humidity difference when the refrigerant is
not supplied: 0.0029[kg/kg], absolute humidity difference when the
refrigerant is supplied: 0.00601[kg/kg]). That is, adsorption
conducted while supplying the refrigerant to the heat exchangers
40,40a may largely improve the absorbing performance. The
isothermal adsorption allows the dew point to be decreased from
12.44.degree. C. to 6.24.degree. C., thus applicable for use at the
low dew point.
[0112] By preparing the fine pores which cause the capillary
condensation on the fin of the heat exchanger, and supplying the
refrigerant to the heat transfer pipes 46, it is possible to
provide a latent heat exchanger having the largely improved
adsorbing performance.
Embodiment 3
[0113] In the above Embodiment 1, the fin 45 is made of aluminum,
however, the material is not limited to the aluminum. For example,
the so-called valve metal may be used as the material of the fin 45
to form fine pores on the surface through the anodic oxidation. The
valve metal refers to a generic name of a metal which forms an
oxide film showing an electrolytic rectifying operation through the
anodic oxidation such as aluminum, tantalum, niobium, titanium,
hafnium, zirconium, zinc, tungsten, bismuth and antimony. Among
them, metals such as aluminum, titanium, zirconium, niobium, and
tantalum may be practically used as the fin 45. The use of those
metals may provide the same effect as aluminum.
Embodiment 4
[0114] FIG. 11 shows an exemplary structure of a refrigeration
cycle apparatus 100 according to Embodiment 4 of the present
invention. The basic structure of the refrigerant circuit composed
by the refrigeration cycle apparatus 100 will be described based on
FIG. 11. The refrigeration cycle apparatus 100 is operated for
cooling, refrigerating, and air conditioning by circulating the
refrigerant.
[0115] The refrigeration cycle apparatus 100 is formed by
sequentially connecting the compressor 10, the condenser 20, the
first throttle device 60, the heat exchanger 41 for
dehumidification/humidification, the second throttle device 61, and
the evaporator 70 with a refrigerant pipe 1. Here, the explanation
will be given on the assumption that the compressor 10 and the
condenser 20 are built into an outdoor unit (unit at the heat
source side) which is disposed outside the space to be
cooled/air-conditioned, and the first throttle device 60, the heat
exchanger 41 for dehumidification/humidification, the second
throttle device 61, and the evaporator 70 are built into the indoor
unit (unit at the load side) disposed inside the subject space.
Here, the condenser 20 is disposed at the outdoor unit, and the
evaporator 70 is disposed at the indoor unit for explaining such
operations for cooling and air-conditioning, however, these roles
will be switched in the case of the heating operation. The
switching is performed by the control unit for controlling a
four-way valve (not shown).
[0116] The refrigerant pipe 1 includes a refrigeration pipe at the
gas side which allows communication of a gaseous refrigerant, and
the refrigeration pipe at the liquid side which allows
communication of the liquid refrigerant. The refrigeration pipe at
the liquid side communicates the refrigerant which has been
condensed and liquefied, and the refrigeration pipe at the gas side
communicates the refrigerant which has been evaporated and
gasified. A blower (not shown) such as the fan for feeding air
outside the subject space (hereinafter, referred to an external
air) into the condenser 20 to promote heat exchange is disposed
around the condenser 20. A blower (not shown) such as the fan is
also disposed around the evaporator 70. The refrigerant to be
enclosed into the refrigerant pipe 1 will be described later.
[0117] The compressor 10 sucks and compresses the refrigerant into
a gaseous state of high temperature/pressure to supply to the
refrigerant pipe 1. The condenser 20 is a heat exchanger to perform
heat exchange between the refrigerant and external air to
condensate/liquefy the refrigerant. The first throttle device 60 is
generally composed of a decompression valve and an expansion valve
such as an electronic expansion valve for decompressing and
expanding the refrigerant.
[0118] The heat exchanger 41 for dehumidification/humidification is
composed of the heat exchangers 40, 40a (hereinafter represented by
the heat exchanger 40) as described in Embodiments 1 to 3, having
fine pores on the surface of the fin 45. The description will be
given, not limited to, on the assumption hereinafter that the heat
exchanger 41 for dehumidification/humidification includes the fine
pores with diameters for increasing the adsorption amount at the
relative humidity of approximately 30% to desorbe the adsorbed
water. The heat exchanger 41 for dehumidification/humidification
mainly as an apparatus to remove the latent heat so as to supply
air within the dehumidified subject space (hereinafter referred to
simply the air) to the evaporator 70 by adsorbing the water. It is
not limited to the usage, however, humidification unit may be
disposed in the refrigeration cycle apparatus 100 to humidify the
subject space using the heat exchanger 41 for
dehumidification/humidification.
[0119] The second throttle device 61 is generally composed of the
decompression valve and the expansion valve such as the electronic
expansion valve to decompress and expand the refrigerant. The
evaporator 70 evaporates and gasifies the refrigerant through the
heat exchange between the refrigerant and the air. The blower
disposed adjacent to the evaporator 70 sucks the air and supplies
the cooled air through the heat exchange in the evaporator 70 to a
region to be cooled (interior space, in the refrigerator, and
refrigerated warehouse). For example, the control unit 80 composed
of such as microcomputers controls the drive frequency of the
compressor 10, and opening of the first throttle device 60 and the
second throttle device 61. In the embodiment, description is given
as a single control unit 80, however, the control units may be
provided for both the outdoor unit and the indoor unit,
respectively and each controller controls the apparatus (unit) that
each unit possesses. Thereby, an associated control is possible by
enabling signal communication.
[0120] The refrigerant used for the refrigeration cycle apparatus
100 will be described. As for the refrigerant used for the
refrigeration cycle apparatus 100, there are the zeotropic
refrigerant mixture, the quasi-azeotropic refrigerant mixture, and
the single refrigerant. Regarding the zeotropic refrigerant
mixture, there is such as R407C (R32/R125/R134a), which is an HFC
(hydrofluoro carbon) refrigerant. Since the zeotropic refrigerant
mixture is a mixture of refrigerants having different boiling
points, it has characteristics that composition ratios of the
liquid-phase refrigerant and gas-phase refrigerant are different.
For the quasi-azeotropic mixture refrigerant, there are such as
R410A (R32/R125), R404A(R125/R143a/R134a), that are HFC
refrigerants.
[0121] The single refrigerant has the type R22 as the HCFC (hydro
chlorofluorocarbon) refrigerant, and R134a as the HFC refrigerant.
The single refrigerant has characteristics that it is not a
mixture, so that it may be easily handled. Such natural
refrigerants as carbon dioxide, propane, isobutene, and ammonia may
also be employed. The R22, R32, R125, R134a, and R143a denote
chlorodifluoromethane, difluoromethane, pentafluoroethane,
1,1,1,2-tetrafluoroethane, and 1,1,1-trifluoroethane, respectively.
Accordingly, the refrigerant suitable for the usage and object of
the refrigeration cycle apparatus 100 may be employed.
[0122] The operation of the refrigeration cycle apparatus 100 will
be described. The heat exchanger 41 for
dehumidification/humidification will be described with respect to
the operation for adsorbing the water in the air. The refrigerant
of high temperature/pressure compressed by the compressor 10 is
condensed/liquefied to be the liquid refrigerant while releasing
heat through the heat exchange with the external air in the
condenser 20. The liquid refrigerant flows into the first throttle
device 60 and decompressed therein to become the low pressure
gas-liquid two-phase refrigerant. The gas-liquid two-phase
refrigerant having the temperature lower than the air flowed into
the heat exchanger 41 for dehumidification/humidification is made
to cool the fin 45 and air passing therearound through the heat
exchange, and part of the air is evaporated and discharged. At this
time, the fin 45 adsorbs the water of the passing air. The
gas-liquid two-phase refrigerant discharged from the heat exchanger
41 for dehumidification/humidification passes through the fully
opened second throttle device 61 to flow into the evaporator 70.
All the gas-liquid two-phase refrigerant is evaporated/gasified
through the heat exchange in the evaporator 70 to be a gaseous
refrigerator, and sucked by the compressor 10 again and
discharged.
[0123] The operation of the heat exchanger 41 for
dehumidification/humidification to desorb the adsorbed water will
be described. The refrigerant of high temperature/pressure
compressed by the compressor 10 becomes the gas-liquid two-phase
refrigerant while releasing the heat to the external air in the
condenser 20. The gas-liquid two-phase refrigerant under the high
pressure state passes through the fully opened first throttle
device 60 and flows into the heat exchanger 41 for
dehumidification/humidification. The gas-liquid two-phase
refrigerant having the higher temperature than the air flowed into
the heat exchanger 41 for dehumidification/humidification heats to
liquefy the fin 45 and the ambient air. The liquefied refrigerant
is decompressed by the second throttle device 61 to become the low
pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase
refrigerant flows into the evaporator 70, evaporated and gasified
entirely into the gaseous refrigerant, and arranged to be sucked by
the compressor 10 again.
[0124] FIG. 12 is a view showing the relationship between the
evaporating temperature and COP (Coefficient of Performance: energy
consumption efficiency). FIG. 12 shows the proportional relation
between the evaporating temperature and the COP. For example, when
the evaporating temperature is 11[.degree. C.], the COP is
approximately 3.1 (shown by (A)). When the evaporating temperature
is increased to 20[.degree. C.], the COP increases up to
approximately 3.9 (shown by (B)). The increase in the evaporating
temperature may improve the COP accordingly.
[0125] In the refrigeration cycle apparatus 100 according to the
present embodiment, the latent heat of the water contained in the
air and the sensible heat may be processed by the heat exchanger 41
for dehumidification/humidification and the evaporator 70
respectively, so that the division of roles is achieved. Unlike the
case where the evaporator 70 processes the latent heat and the
sensible heat, the evaporating temperature of the refrigerant can
be set higher. Thus, the air conditioning system can prevent
deposition of the frost and needs no defrosting operation even when
conventionally the evaporating temperature has to set to be the
value lower than the dew point in the evaporator 70 and the frost
deposited.
[0126] The use of the condensed exhaust heat in the condenser 20
may desorb the water adsorbed in the heat exchanger 41 for
dehumidification/humidification (fin 45). The desorbed water may be
disposed, or used for humidification. The heating device such as
the heater for desorbing the water is no longer necessary, thus
requiring no power for the heating device. This makes it possible
to largely reduce the power consumption.
[0127] When the refrigeration cycle apparatus 100 according to the
present embodiment is applied to the refrigerated warehouse under
the conditions where external air is maintained at the dry-bulb
temperature of 30[.degree. C.], the relative humidity of 60[%], and
absolute humidity of 16.04[g/kg], the control unit 80 may control
each apparatus so that the refrigeration cycle apparatus is
operated for the refrigerated room (air-conditioned space) in the
refrigerated warehouse to be maintained and continued under the
conditions of the dry-bulb temperature 10[.degree. C.], the
relative humidity 60[%], and the absolute humidity 4.56[g/kg].
[0128] In the refrigeration cycle apparatus according to Embodiment
4, by making the water adsorbed by the fin 45 using the heat
exchanger 41 for dehumidification/humidification as described in
Embodiments 1 to 3 as the dehumidifying/humidifying device, the
evaporating temperature of the refrigerant in the heat exchange
with the air in the evaporator 70 does not have to be set in
consideration of the latent heat caused by the water, so that the
refrigerant may be controlled to the temperature in consideration
of the sensible heat. This makes it possible to make the
compression ratio in the compressor of the refrigeration cycle
apparatus small, thus improving the energy performance represented
by the COP in the refrigeration cycle apparatus as an index.
Embodiment 5
[0129] FIG. 13 shows an exemplary structure of the refrigeration
cycle apparatus 100a according to Embodiment 3 of the present
invention. The refrigeration cycle apparatus 100a of the present
embodiment is formed, but is not limited to, as an air conditioning
system for heating/cooling operations. The apparatuses shown in
FIG. 13 with the same reference numerals as those described in
Embodiment 4 perform the same functions, so that explanations will
be omitted.
[0130] The refrigeration cycle apparatus 100a is formed by the
compressor 10, the condenser 20, the first on-off valve 30 and the
second on-off valve 31 which are provided in parallel, the heat
exchangers 41a and 41b for dehumidification/humidification which
are provided in parallel, back-flow prevention members 50 and 51
which are provided in parallel, the throttle device 62, and the
evaporator 70, being sequentially connected with the refrigerant
pipe 1. As described in Embodiments 1 to 3, the refrigeration cycle
apparatus 100a includes heat exchangers 41a (a first heat
exchanger) and 41b (a second heat exchanger) for
dehumidification/humidification that are the heat exchangers 40
having the fin 45 with fine pores formed on the surface. These two
heat exchangers 41a and 41b for dehumidification/humidification are
independently built into the indoor unit independently.
[0131] The refrigerant pipe 1 is branched into refrigerant pipes 1a
and 1b. After the on-off valve 30, the heat exchanger 41a for
dehumidification/humidification, and the back-flow prevention
member 50 are connected by refrigerant pipe 1a, and the on-off
valve 31, the heat exchanger 41b for
dehumidification/humidification and the back-flow prevention member
51 being connected by refrigerant pipe 1b respectively, these are
joined together again. The refrigerant flowing in the refrigerant
pipe 1 may employ the one described in Embodiment 2. The
refrigeration cycle apparatus 100a is provided with a
temperature/humidity detection unit 81 (a first
temperature/humidity detection unit) at the inlet of the air
passage of the evaporator 70 for detecting the temperature and
humidity of air flowing into the evaporator 70.
[0132] The temperature/humidity detection unit 81 may be of any
type so far as the temperature and the humidity are detected and
types are not limited in particular. For example, the temperature
sensor such as the thermistor, thermometer, humidity sensor, and
hygrometer may be employed.
[0133] The on-off valves 30 and 31 function as flow passage
selecting units for selecting the refrigerant circuit that are not
limited to the particular type. The back-flow prevention members 50
and 51 prevent back-flow of the refrigerant flowing through the
refrigerant pipes 1a and 1b. Such as a check valve may be employed,
but is not limited to the particular type. The throttle device 62
is generally composed of a decompression valve and expansion valve
for decompressing the refrigerant to expand. The electronic
expansion valve may be employed, for example. The control unit 80
according to the present embodiment controls the respective
apparatuses including the on-off valves 30, 31 in addition to the
controlling operations described above. The control unit further
performs the air passage control by switching the air passage
switching units 301a to 304a, and 301b to 304b described later, and
calculates the relative humidity of the air in the evaporator 70
based on the information from the temperature/humidity detection
unit 81 to convert the relative humidity into the dew point
(dew-point temperature).
[0134] FIG. 14 shows a structure of an indoor unit 300 where the
evaporator 70 and the like are built-in. The indoor unit 300 shown
in FIG. 14 is partially disposed in the refrigerated warehouse
(air-conditioned space) 400 and the rest portion is disposed at the
external air side 500. In the indoor unit 300, the heat exchangers
41a and 41b for dehumidification/humidification and the evaporator
70 as shown in FIG. 13 are built-in. Blowers 90 and 91 such as a
centrifugal fan and axial flow fan are disposed adjacent to the
heat exchangers 41a and 41b for dehumidification/humidification.
The indoor unit 300 is provided with a duct 310 which not only
feeds air from the evaporator 70 to the refrigerated warehouse 400
but also sucks the air.
[0135] The indoor unit 300 is structured to disconnect the air
passage (air flow) between the heat exchangers 41a and 41b for
dehumidification/humidification. The indoor unit 300 is capable of
switching the air passage. By switching the air passage the heat
exchangers 41a and 41b for dehumidification/humidification can be
communicated with the inside of the refrigerated warehouse 400 and
the external air 500. The operation for switching the air passage
is performed by the air passage switching units 301a and 301b, 302a
and 302b, 303a and 303b, and 304a and 304b, respectively. The air
passage may be finely adjusted by the air passage adjustment units
305a and 305b.
[0136] The air flow in the indoor unit 300 will be described.
Referring to FIG. 14, the air passage switching units 301a, 302b,
303b, and 304a are opened, and the air passage switching units
301b, 302a, 303a, and 304b are closed. When the respective air
passage switching units are in the aforementioned state, the
built-in space of the heat exchanger 41a for
dehumidification/humidification is communicated with the external
air 500 to allow the air to flow from outside (arrow A). The
built-in space of the heat exchanger 41b for
dehumidification/humidification is communicated with the inside of
the refrigerated warehouse 400 via the duct 310 to allow the air
(for example, the temperature 10[.degree. C.] and relative humidity
60[%])(arrow B) to flow in.
[0137] In the above structured air passages, the heat exchanger 41a
for dehumidification/humidification performs desorption, and the
heat exchanger 41b for dehumidification/humidification performs
adsorption. Thereby, the latent heat may be processed by the heat
exchanger 41b for dehumidification/humidification and the sensible
heat may be processed by the evaporator 70 individually. Meanwhile,
when the open/closed states of each air passage switching unit are
inverted, the air flows into the built-in space of the heat
exchanger 41a for dehumidification/humidification, and the expanded
air flows into the built-in space of the heat exchanger 41b for
dehumidification/humidification. The heat exchanger 41a for
dehumidification/humidification performs adsorption, and the heat
exchanger 41b for dehumidification/humidification performs
desorption, respectively.
[0138] FIG. 15 is an explanatory view showing the state where the
air passages in the indoor unit 300 is switched. Referring to FIG.
15(a), the air passage switching units 301a, 302b, 303b and 304a
are closed, and the air passage switching units 301b, 302a, 303a
and 304b are opened.
[0139] As shown in FIG. 15(a), the built-in space of the heat
exchanger 41b for dehumidification/humidification is communicated
with the external air 500 to allow the external air to flow in
(arrow C). The built-in space of the heat exchanger 41a for
dehumidification/humidification is communicated with the inside of
the refrigerated warehouse 400 via the duct 310 to allow the air to
flow in (arrow D). At this time, the heat exchanger 41b for
dehumidification/humidification desorbs the water, and the heat
exchanger 41a for dehumidification/humidification adsorbs the
water. FIG. 15(b) shows the same as what is shown in FIG. 14, so
that the explanation will be omitted.
[0140] FIG. 16 is a P-h diagram (Mollier diagram) which represents
the refrigerant state in the refrigeration cycle. The refrigerant
state in the refrigeration cycle will be described based on FIG.
16. The vertical axis of the diagram denotes an absolute pressure
(P), and the horizontal axis denotes enthalpy (h). Referring to
FIG. 16, the region surrounded by the saturated liquid line and the
saturated vapor line represents the refrigerant in the gas-liquid
two-phase state. The region to the left of the saturated liquid
line represents the liquefied refrigerant, and the region to the
right of the saturated vapor line represents the gaseous
refrigerant. That is, in the states (1) and (5), the refrigerant is
gaseous, and in the states (2) and (4), the refrigerant is in the
gas-liquid two-phase state. In the state (3), the refrigerant is
liquefied.
[0141] The operation of the refrigeration cycle apparatus 100a will
be described based on FIGS. 13 and 16. Descriptions will be given
to when the on-off valve 30 is opened, the on-off valve 31 is
closed, the heat exchanger 41a for dehumidification/humidification
is operated for desorbing the water, and the heat exchanger 41b for
dehumidification/humidification is operated for adsorbing the
water. Since the on-off valve 31 is closed, the refrigerant does
not flow into the heat exchanger 41b for
dehumidification/humidification.
[0142] The refrigerant in the gaseous state of high
temperature/pressure state compressed by the compressor 10 (in the
state (1) shown in FIG. 16) flows into the condenser 20. The
refrigerant in the aforementioned state turns into the gas-liquid
two-phase state while partially releasing heat to the external air
in the condenser 20 (the state (2) shown in FIG. 16). The
gas-liquid two-phase refrigerant of high pressure state flows into
the heat exchanger 41a for dehumidification/humidification, and
passes through the heat transfer pipe 46. At this time, a heat
exchange between the refrigerant and the air is conducted to
increase temperature of the fin 45 and the ambient air to reduce
the relative humidity. As a result, the water adsorbed on the fin
45 is desorbed. The gas-liquid two-phase refrigerant turns into the
liquefied refrigerant (the state (3) shown in FIG. 16).
[0143] The refrigerant flows in the back-flow prevention member 50
to be decompressed in the throttle device 62. The decompressed
refrigerant becomes a low pressure gas-liquid two-phase refrigerant
(the state (4) shown in FIG. 16). The gas-liquid two-phase
refrigerant flows into the evaporator 70 and is evaporated by
removing heat from the air to become a low pressure gaseous
refrigerant (the state (5) shown in FIG. 16). The air here adsorbs
the water by the heat exchanger 41b for
dehumidification/humidification as described later. The air is
cooled to flow out into the refrigerated warehouse 400. Then, the
gaseous refrigerant is sucked by the compressor 10 again to
circulate in the refrigerant circuit. The cooling/refrigerating
operations are conducted by circulating the refrigerant in the
refrigerant circuit while changing the states of the refrigerant by
repeating the heat absorbing/releasing operations.
[0144] FIG. 17 is a psychrometric diagram for explaining the
operation of the heat exchanger 41b for
dehumidification/humidification in the refrigeration cycle
apparatus 100a. The operation of the above refrigeration cycle
apparatus 100a will be described using the psychrometric diagram
and the structural view of FIG. 14. In FIGS. 14 and 17, for the air
passing through the heat exchanger 41b for
dehumidification/humidification made to be communicated with the
inside of the refrigerated warehouse 400, descriptions are given to
the state (1) shown in FIG. 17 representing the state of the air
before passing through the heat exchanger 41b for
dehumidification/humidification, the state (2) shown in FIG. 17
representing the state of the air immediately after passing through
the heat exchanger 41b for dehumidification/humidification, and the
state (3) shown in FIG. 17 representing the state of the air
immediately after the heat exchange with the evaporator 70.
[0145] Descriptions will be given to when the heat exchanger 41b
for dehumidification/humidification adsorbs the water content of
the air inside the refrigerated warehouse 400. The air in the state
(1) is the dry-bulb temperature 10[.degree. C.], the relative
humidity 60[%], and the absolute humidity 4.56[g/kg]. When the air
in the aforementioned state flows into the heat exchanger 41b for
dehumidification/humidification, the air is brought into the state
(2) along an equi-enthalpy line to be fed to the evaporator 70,
where the relative humidity being reduced from 60[%] to 30[%], the
absolute humidity being reduced from 4.56[g/kg] to 2.96[g/kg], and
the dry-bulb temperature being increased from 10[.degree. C.] to
14[.degree. C.].
[0146] Since the amount of the water adsorbed by the heat exchanger
41b for dehumidification/humidification becomes large in the region
where the relative humidity is equal to or higher than
approximately 30%, it is possible to dehumidify the air in the
state (1). The air in the state (2) is cooled by the removal of the
sensible heat through the heat exchange of the evaporator 70 in the
state of constant absolute humidity to turn into the air of the
state (3) where the relative humidity is lower than 100[%] and the
dry-bulb temperature is -2[.degree. C.].
[0147] In most cases, the inside of the refrigerated warehouse 400
is generally kept at the temperature range lower than 10[.degree.
C.], and the evaporating temperature is required to set lower than
0[.degree. C.]. However, the refrigeration cycle apparatus 100a is
capable of setting the evaporating temperature of the evaporator 70
(14[.degree. C.] of the state (2)) to be higher than the dew-point
temperature (for example, the dew-point temperature -2.9[.degree.
C.] of the state (2)) so as not to allow the refrigeration cycle to
execute a defrosting operation for removing the frost formed on the
evaporator 70.
[0148] The control unit 80 may be configured to adjust the
evaporating temperature of the evaporator 70 to increase by
controlling the opening of the throttle device 62, the drive
frequency of the compressor 10, the rotating speed of the blower 91
and the like. As described in FIG. 12, if the evaporating
temperature is set high, the COP may be improved by that amount.
Since the evaporating temperature of the evaporator 70 may be
higher than the dew point, no drain occurs. That is, no drain pipe
is required, thus reducing the manufacturing cost.
[0149] The control unit 80 calculates the relative humidity of the
air in the evaporator 70 based on the information from the
temperature/humidity detection unit 81. The calculated relative
humidity is then converted into the dew point. The dew point may be
detected based on the converted result. Air in the state (3) is
diffused into the refrigerated warehouse 400 to maintain the
dry-bulb temperature at 10[.degree. C.] or lower. The amount of the
water content which can be adsorbed by the heat exchanger 41b for
dehumidification/humidification is limited. When it is determined
that the relative humidity of the heat exchanger 41g for
dehumidification/humidification at the outlet of the air passage
becomes equal to or larger than a predetermined threshold value
based on the detection information from the temperature/humidity
detection unit 81, the control unit 80 switches the on-off valve 30
from the open to the closed state, and the on-off valve 31 from the
closed to the open state to switch the refrigerant flow. The
gaseous refrigerant of high temperature/pressure is made to flow
into the heat exchanger 41b for dehumidification/humidification to
increase temperatures of the fin 45 and the ambient air.
[0150] That is, the operation of the heat exchanger 41b for
dehumidification/humidification which has been adsorbing the water
is switched to desorb the water. When temperatures of the fin 45 of
the heat exchanger 41b for dehumidification/humidification and the
ambient air are increased, the relative humidity is decreased to
release the adsorbed water for reproduction. Meanwhile, the
refrigerant flow passage is switched, so that the heat exchanger
41a for dehumidification/humidification comes to adsorb the water
in the air. The heat exchanger 41a for
dehumidification/humidification is structured to adsorb the water
in the air such that the air inside the warehouse 400 is
dehumidified from the state (1) to (2) as shown in FIG. 17.
[0151] The amount of the water which can be adsorbed by the heat
exchanger 41a for dehumidification/humidification is limited. When
it is determined that the relative humidity of the heat exchanger
41a for dehumidification/humidification at the outlet side of the
air passage becomes equal to or higher than a predetermined
threshold value based on the detection information from the
temperature/humidity detection unit 81, the control unit 80
switches the on-off valve 30 from the closed to the open state, and
the on-off valve 31 from the open to the closed state to switch the
refrigerant flow. The gaseous refrigerant of high
temperature/pressure is fed into the heat exchanger 41a for
dehumidification/humidification to increase temperatures of the fin
45 and the ambient air such that the relative humidity is lowered
to desorb the water.
[0152] As mentioned above, when one of the heat exchangers for
dehumidification/humidification (heat exchanger 41b for
dehumidification/humidification) adsorbs the water, the
refrigeration cycle apparatus 100a is structured to allow the other
heat exchanger for dehumidification/humidification (heat exchanger
41a for dehumidification/humidification) to desorb the water. The
operations of the heat exchangers are alternately switched
depending on the amount of the adsorbed water. Switching of the air
passage to select the refrigerant flow passage allows the humidity
(latent heat) of the air in the refrigerated warehouse 400 to be
removed continuously.
[0153] Table 2 collectively shows control states of the on-off
valves 30 and 31 (flow passage switching unit) and air passage
switching units 301a to 304b, and functions of the heat exchangers
41a and 41b for dehumidification/humidification. In Table 2,
pattern 1 represents that the heat exchanger 41a for
dehumidification/humidification adsorbs water, and the heat
exchanger 41b for dehumidification/humidification desorbs the
adsorbed water as shown in FIG. 15(a). Pattern 2 represents that
the heat exchanger 41a for dehumidification/humidification desorbs
the adsorbed water, and the heat exchanger 41b for
dehumidification/humidification adsorbs the water as shown in FIG.
15(b). The continuous operation may be performed by switching the
patterns 1 and 2.
TABLE-US-00002 TABLE 2 Air Air Air Air passage passage passage
passage Heat On-off switching switching switching switching
exchanger valve unit unit unit unit Pattern 41a 41b 30 31 301a 301b
302a 302b 303a 303b 304a 304b 1 Adsorb Desorb Close Open Close Open
Open Close Open Close Close Open 2 Desorb Adsorb Open Close Open
Close Close Open Close Open Open Close
[0154] As described above, the refrigeration cycle apparatus 100a
according to Embodiment 5 is structured to allow the heat
exchangers 41a and 41b for dehumidification/humidification composed
of the heat exchanger 40 according to Embodiments 1 to 3 to
alternately adsorb the water in air in the refrigerated warehouse
400 continuously. This makes it possible to eliminate the
defrosting operation conventionally frequently performed to further
reduce the power consumption for the defrosting operation. The
evaporating temperature of the evaporator 70 may be set higher than
the dew-point temperature to enable an efficient operation of the
refrigeration cycle.
[0155] Since the water adsorbed by the heat exchangers 41a and 41b
for dehumidification/humidification is configured to be desorbed
using the heat (exhaust heat which is not required for cooling the
inside of the refrigerated warehouse 400) of the refrigerant
condensed by the condenser 20, no specific heating device for the
desorption is required, and the space for accommodation can be
saved, so that no electric power is required for heating by the
heating unit.
[0156] The refrigeration cycle apparatus 100a does not require a
high pressure in excess of a critical pressure. That is, the
compressor 10, the condenser 20 and the refrigerant pipe 1
(including refrigerant pipes 1a and 1b) connecting those may be low
in pressure-resistant performance, so that manufacturing costs can
be reduced. The compression ratio of the refrigerant in the
compressor 10 may be suppressed, thus improving the operation
efficiency of the compressor 10. That is, COP can be significantly
improved and energy saving can be achieved.
Embodiment 6
[0157] FIG. 18 shows an exemplary structure of a refrigeration
cycle apparatus 100b according to Embodiment 6 of the present
invention. Descriptions will be given, but not limited in
particular, to that the refrigeration cycle apparatus 100b of the
present embodiment is, for example, an air conditioning system for
cooling/heating operations. In FIG. 18, since the apparatuses
designated with the same reference numerals as those described in
Embodiments 4 and 5 perform the same functions, explanations will
be omitted.
[0158] The refrigeration cycle apparatus 100b is formed by the
compressor 10, the condenser 20, the first and the second on-off
valves 32 and 33 provided in parallel, the heat exchangers 41c and
41d for dehumidification/humidification provided in parallel, the
on-off valves 34 and 35 provided in parallel, the throttle device
85 (third throttle device), and the evaporator 70, being
sequentially connecting with the refrigerant pipe 1. The
refrigeration cycle apparatus 100b is also provided with the heat
exchangers 41c (a first heat exchanger) and 41d (a second heat
exchanger) for dehumidification/humidification that are the heat
exchanger 40 having the fin 45 with the fine pores formed on the
surface. Those two heat exchangers 41c and 41d for
dehumidification/humidification are built into the indoor unit
separately.
[0159] The refrigerant pipe 1 is branched into the refrigerant
pipes 1c and 1d. After the on-off valve 32, the heat exchanger 41c
for dehumidification/humidification, and the on-off valve 34 are
connected by the refrigerant pipe 1c, and the on-off valve 33, the
heat exchanger 41d for dehumidification/humidification, and the
on-off valve 35 are connected by the refrigerant pipe 1d, these are
then joined again. The refrigerant flowing in the refrigerant pipe
1 may employ the refrigerant described above. The refrigerant pipes
1c and 1d include a bypass pipe 2 (a first bypass pipe) branched
from the refrigerant pipe 1c between the on-off valve 32 and the
heat exchanger 41c for dehumidification/humidification to join with
the refrigerant pipe 1d between the heat exchanger 41d for
dehumidification/humidification and the on-off valve 35, and a
bypass pipe 3 (a second bypass pipe) branched from the refrigerant
pipe 1d between the on-off valve 33 and the heat exchanger 41d for
dehumidification/humidification to join with the refrigerant pipe
1c between the heat exchanger 41c for
dehumidification/humidification and the on-off valve 34.
[0160] The bypass pipe 3 includes a throttle device 63 (a first
throttle device) and an on-off valve 36 (a third on-off valve). The
bypass pipe 2 includes a throttle device 64 (a second throttle
device) and an on-off valve 37 (a fourth on-off valve). The
refrigeration cycle apparatus 100b includes a temperature/humidity
detection unit 81 for detecting the temperature/humidity of the
evaporator 70 at the inlet side of the air passage thereof, and a
temperature/humidity detection unit 82 (a second
temperature/humidity detection unit) for detecting the
temperature/humidity of the heat exchangers 41c and 41d for
dehumidification/humidification at the outlet side of the air
passage of the heat exchanger 41c for
dehumidification/humidification, respectively.
[0161] The temperature/humidity detection units 81 and 82 may be of
any type so far as the temperature and the humidity are detected
and types are not limited in particular. For example, the
temperature sensor such as the thermistor, thermometer, humidity
sensor, and hygrometer may be employed. In the example, the
apparatus employs a single unit of the temperature/humidity
detection units 81 and 82, respectively, however, plural units may
be employed without being limited to the above. The
temperature/humidity detection unit 82 may be disposed at the
outlet sides of the respective air passages of the heat exchangers
41c and 41d for dehumidification/humidification.
[0162] The refrigeration cycle apparatus 100b is provided with a
control unit 80a which controls a drive frequency of the compressor
10, opening of the on-off valves 32 to 37, and opening of the
throttle devices 63, 64 and 85. The on-off valves 32 to 37 are
operated for switching the flow passages, not limited to a specific
type. The throttle devices 63, 64 and 85 are generally composed of
the decompression and expansion valves to decompress and expand the
refrigerant, and may be composed of an electronic expansion valve
and the like.
[0163] In addition to controlling each apparatus, the control unit
80a calculates the relative humidity of the heat exchanger 41c for
dehumidification/humidification at the outlet side of the air
passage based on the signal which contains data from the
temperature/humidity detection unit 82 to convert the calculated
relative humidity into the dew point (dew-point temperature). The
control unit 80 also controls the relative humidity in the
evaporator 70 based on the information from the
temperature/humidity detection unit 81 to convert and the
calculated relative humidity into the dew point (dew-point
temperature). When the desorption/adsorption function is switched
between the heat exchangers 41c and 41d for
dehumidification/humidification, the control unit 80a calculates
the relative humidity of the heat exchanger 41d for
dehumidification/humidification at the outlet side of the air
passage to convert the calculated relative humidity into the dew
point (dew-point temperature).
[0164] FIG. 19 shows a structure of an indoor unit 300a where the
evaporator 70 and the like are built-in. The basic structure of the
indoor unit 300a will be described based on FIG. 19. Descriptions
will be given to differences from the indoor unit 300 shown in FIG.
14. In FIG. 19, a part of the indoor unit 300a is disposed inside
(air-conditioned space) 401 of the room, and the rest is disposed
at the side of the external air 500. In the indoor unit 300a, the
heat exchangers 41c and 41d for dehumidification/humidification and
the evaporator 70 shown in FIG. 18 are built-in.
[0165] The indoor unit 300a is structured to disconnect the air
passage between the heat exchangers 41c and 41d for
dehumidification/humidification. The indoor unit 300a is allowed to
switch the air passage to communicate the heat exchangers 41c and
41d for dehumidification/humidification with the interior 401 and
the external air 500. The switching of the air passage may be
performed by air passage switching units 311a and 311b, 312a and
312b, 313a and 313b, and 314a and 314b, respectively. The fine
adjustment of the air passage may be performed by the air passage
adjustment units 315a and 315b.
[0166] The air flow in the indoor unit 300a will be described. FIG.
19 shows that the air passage switching units 311a, 312b, 313b and
314a are opened, and the air passage switching units 311b, 312a,
313a and 314b are closed. In the aforementioned state of the air
passage switching units, the built-in space of the heat exchanger
41c for dehumidification/humidification is communicated with the
external air 500 to allow the air to flow from outside (arrow A).
The built-in space of the heat exchanger 41d for
dehumidification/humidification is communicated with the interior
401 via the duct 310 to allow the air (for example, temperature
26[.degree. C.] and relative humidity 60[%]) to flow in (arrow
B).
[0167] When the air passages are formed as described above, the
heat exchanger 41c for dehumidification/humidification performs the
desorption, and the heat exchanger 41d for
dehumidification/humidification performs the adsorption. Thereby,
the heat exchanger 41d for dehumidification/humidification
processes latent heat, and the evaporator 70 processes sensible
heat separately. Meanwhile, when the open-close states of the
respective air passage switching units are inverted, the heat
exchanger 41c for dehumidification/humidification performs
adsorption, and the heat exchanger 41d for
humidification/humidification performs desorption.
[0168] FIG. 20 is an explanatory view showing the state where the
air passage of the indoor unit 300a is switched. Referring to FIG.
20, a portion of the indoor unit 300a is disposed in the interior
401, and the rest is disposed at the side of the external air 500.
FIG. 20(a) shows that the air passage switching units 311a, 312b,
313b and 314a are closed, and the air passage switching units 311b,
312a, 313a and 314b are closed.
[0169] Referring to FIG. 20(a), the built-in space of the heat
exchanger 41d for dehumidification/humidification is communicated
with the external air 500 to allow the external air to flow in
(arrow C). The built-in space of the heat exchanger 41c for
dehumidification/humidification is communicated with the interior
401 via the duct 310 to allow the air to flow in (arrow D). At this
time, the heat exchanger 41d for dehumidification/humidification
desorbs water, and the heat exchanger 41c for
dehumidification/humidification adsorbs the water, respectively.
FIG. 20(b) shows the same as what is shown in FIG. 19, so that the
explanation will be omitted.
[0170] In the case where the refrigeration cycle apparatus 100b is
applied to an air-conditioning apparatus such as the room
air-conditioner and all-in-one air conditioning system with the
condition of the external air 500 being kept at the dry-bulb
temperature 30[.degree. C.], the relative humidity 60[%], and the
absolute humidity 16.04[g/kg], the control unit 80a should control
the respective apparatuses to operate the refrigeration cycle
apparatus 100b while maintaining and continuing the interior 401
(air-conditioned space) under conditions of the dry-bulb
temperature 26[.degree. C.], the relative humidity 60[%], and the
absolute humidity 8.74[g/kg].
[0171] FIG. 21 is a P-h diagram (Mollier diagram) which represents
the refrigerant state in the refrigeration cycle. The refrigerant
state in the refrigeration cycle will be described based on FIG.
21. Referring to FIG. 21, it is configured to be able to understand
that the refrigerant is gaseous in the states (1) and (7). The
refrigerant is in the gas-liquid two-phase state in the states (2),
(4), (5) and (6). The refrigerant is liquefied in the state
(3).
[0172] The operation of the refrigeration cycle apparatus 100b will
be described based on FIGS. 18 and 21. Descriptions will be given
on the operation of the refrigeration cycle apparatus 100b when the
on-off vales 32, 34 and 35 are opened, the on-off valves 33, 37 and
36 are closed, the heat exchanger 41c for
dehumidification/humidification is operated as the heat exchanger
for desorption, and the heat exchanger 41d for
dehumidification/humidification is operated as the heat exchanger
for adsorption.
[0173] The gaseous refrigerant of high temperature/pressure
compressed by the compressor 10 (the state (1) shown in FIG. 21)
flows into the condenser 20. The refrigerant in the aforementioned
state turns into the gas-liquid two-phase state (state (2) shown in
FIG. 21) while partially releasing the heat to the external air by
the condenser 20. The high pressure gas-liquid two-phase
refrigerant flows into the heat exchanger 41c for
dehumidification/humidification. The gas-liquid two-phase
refrigerant flowing into the heat exchanger 41c for
dehumidification/humidification increases the temperatures of the
fin 45 and the ambient air to reduce the relative humidity.
Thereby, the water adsorbed in the fin 45 is desorbed. The
gas-liquid two-phase refrigerant turns into the liquefied
refrigerant (state (3) shown in FIG. 21).
[0174] The aforementioned refrigerant flows through the on-off
valve 36 to be decompressed by the throttle device 63. The
decompressed refrigerant turns into the low pressure gas-liquid
two-phase state (state (4) shown in FIG. 21, here, the first
evaporating temperature). Then the gas-liquid two-phase refrigerant
flows into the heat exchanger 41d for
dehumidification/humidification to lower the temperatures of the
fin 45 and the ambient air with the first evaporating temperature
lower than the air and enhance the adsorbing performance. The
gas-liquid two-phase refrigerant flowing into the heat exchanger
41d for dehumidification/humidification partially evaporates to
turn into the low pressure gas-liquid two-phase refrigerant (state
(5) shown in FIG. 21). The gas-liquid two-phase refrigerant is
further decompressed by the throttle device 85 to be a second
evaporating temperature (state (6) shown in FIG. 21), then flows
into the evaporator 70 to turn into a low pressure gaseous
refrigerant by absorbing the sensible heat of the air through the
heat exchange (state (7) shown in FIG. 21). The gaseous refrigerant
is sucked by the compressor 10 again to circulate in the
refrigerant circuit.
[0175] The refrigeration cycle apparatus 100b is structured to
allow the refrigerant which has passed through one of the heat
exchangers for dehumidification/humidification (heat exchanger 41c
for dehumidification/humidification) to flow into the other heat
exchanger for dehumidification/humidification (heat exchanger 41d
for dehumidification/humidification) via a bypass pipe (bypass pipe
3). As a result, the heat exchanger 41 for
dehumidification/humidification efficiently desorbs the water using
the heat of the refrigerant related to condensation, and the other
heat exchanger 41 for dehumidification/humidification efficiently
adsorbs the water using the heat of the refrigerant related to
evaporation to enhance adsorption/desorption performance and
improve the performance of the refrigeration cycle apparatus.
[0176] FIG. 22 is a psychrometric diagram for explaining the
operation of the heat exchanger 41d for
dehumidification/humidification of the refrigeration cycle
apparatus 100b. The operation of the above-mentioned refrigeration
cycle apparatus 100b will be described referring to the
psychrometric diagram and the structure shown in FIG. 19. Referring
to FIGS. 19 and 22, for the air passing through the heat exchanger
41d for dehumidification/humidification communicating with the
interior 401, the state (1) shown in FIG. 22 represents the state
of air before passing through the heat exchanger 41d for
dehumidification/humidification, the point (2) shown in FIG. 22
represents the state of air immediately after passing through the
heat exchanger 41d for dehumidification/humidification, and the
point (3) shown in FIG. 22 represents the state of air immediately
after the heat exchange with the evaporator 70.
[0177] The operation of the heat exchanger 41d for
dehumidification/humidification when adsorbing the water of air in
the interior 401 will be described. The air in the state (1) is the
dry-bulb temperature of 26[.degree. C.] and the relative humidity
60[%] when the air in this state flows into the heat exchanger 41d
for dehumidification/humidification, the air is subjected to
isothermal or cooling adsorption in the heat exchanger 41d to turn
into the state (2) to flow into the evaporator 70. Same the amount
of water which can be adsorbed by the heat exchanger 41b for
dehumidification/humidification is increased in the region of the
relative humidity of 30% or higher, the air in the state (1) can be
dehumidified.
[0178] The air in the state (2) is subjected to heat exchange by
the evaporator 70 to turn into the air in the state (3). The air in
the state (2) is cooled with only the sensible heat being removed
at a constant absolute humidity by the evaporator 70 to turn into
the state (3) where the relative humidity is lower than 100[%] and
the dry-bulb temperature is 14[.degree. C.]. The air in the state
(3) is supplied to the interior 401.
[0179] The control unit 80a controls the opening of the throttle
devices 63 and 85, the drive frequency of the compressor 10, and
the rotating speed of the blower 91, and adjusts the first
evaporating temperature to be equal to or higher than the dew point
(in the present embodiment, 18[.degree. C.]) of the intake air in
the heat exchanger 41d for dehumidification/humidification. The
control unit controls the second evaporating temperature to be
equal to or higher than the dew point (in the present embodiment,
14[.degree. C.]) of air at the outlet of the heat exchanger 41d for
dehumidification/humidification. The control unit 80a converts the
data of temperature and humidity detected by the
temperature/humidity detection units 81 and 82 into the dew point.
FIG. 22 shows the first evaporating temperature of 18[.degree. C.],
and the second evaporating temperature of 14[.degree. C.].
[0180] The amount of water is limited which can be adsorbed by the
heat exchanger 41d for dehumidification/humidification functioning
as a heat adsorption exchanger. When it is determined that the
relative humidity in the evaporator 70 becomes equal to or higher
than a predetermined threshold value based on the data detected by
the temperature/humidity detection unit 81, the control unit 80a
switches on-off valves 32, 36 and 35 from the open to the closed
state, and on-off valves 33, 37 and 34 from the closed to the open
state to change the refrigerant flow. A high temperature/pressure
gaseous refrigerant is fed into the heat exchanger 41d for
dehumidification/humidification to increase the temperatures of the
fin 45 and the ambient air for desorption and reproduction.
[0181] Since the refrigerant flow passage is switched, the heat
exchanger 41c for dehumidification/humidification is operated as an
adsorption heat exchanger. In the heat exchanger 41c for
dehumidification/humidification, the water contained in the air is
adsorbed. The refrigeration cycle apparatus 100b, alternately
switches heat exchangers according to the water adsorption amount
such that when one of the heat exchangers for
dehumidification/humidification (heat exchanger 41d for
dehumidification/humidification) is adsorbs the water, the other
heat exchanger for dehumidification/humidification (heat exchanger
41c for dehumidification/humidification) desorbs the water. The air
in the interior 401 may be continuously dehumidified (latent heat
may be removed) by switching the air passages.
[0182] The external air for example, the dry-bulb temperature
32[.degree. C.] and the relative humidity 60[%], is supplied from
the external air 500 side to the heat exchanger 41c for
dehumidification/humidification by the blower 90. The heat
exchanger 41c for dehumidification/humidification desorbs the
adsorbed water. Then, the absolute humidity is increased through
the desorption, and the air is discharged to the external air 500
again. The air is merely discharged here, however, the desorbed
water may be used for humidification. In this way, the latent heat
may be removed by the heat exchangers 41c, 41d for
dehumidification/humidification, and the sensible heat may be
removed by the evaporator 70. The exhaust heat generated by
condensation in the condenser 20 may be used for desorbing the
adsorbed water, air-conditioning and refrigerating performance is
significantly improved.
[0183] Table 3 shows control states of the on-off valves 32 to 37
and functions of the heat exchangers 41c, 41d for
dehumidification/humidification. Referring to Table 3, the pattern
1 shows that the heat exchanger 41d for
dehumidification/humidification adsorbs the water, and the heat
exchanger 41c for dehumidification/humidification desorbs the
adsorbed water as shown in FIG. 20(b). Then, the on-off valves 32,
36 and 35 are opened, and the on-off valves 33, 37 and 34 are
closed. The pattern 2 shows that the heat exchanger 41d for
dehumidification/humidification desorbs the adsorbed water, and the
heat exchanger 41c for dehumidification/humidification adsorbs the
water as shown in FIG. 20(a). Then, the on-off valves 33, 37 and 34
are opened, and the on-off valves 32, 36 and 35 are closed.
Continuous operations may be performed by alternately switching the
patterns 1 and 2.
TABLE-US-00003 TABLE 3 On-off On-off On-off Pat- Heat Exchanger
valve valve valve tern 41c 41d 32 33 36 37 34 35 1 Desorp-
Adsorption Open Close Open Close Close Open tion 2 Adsorp-
Desorption Close Open Close Open Open Close tion
[0184] When either of the heat exchangers 41c and 41d for
dehumidification/humidification desorbs the water, the refrigerant
is condensed therein. When adsorbing the water, the refrigerant is
evaporated. Functions of the heat exchangers 41c and 41d for
dehumidification/humidification may be switched by controlling
opening of each on-off valve to switch the refrigerant flow and
continuous operation is possible while switching adsorption and
desorption alternately.
[0185] When the air-conditioned space is at the dry-bulb
temperature of 26[.degree. C.] and the relative humidity of 60[%],
and the external air is at the dry-bulb temperature of 32[.degree.
C.] and the relative humidity of 60[%], the conventional
refrigeration cycle apparatus is used to adjust the balance of the
condenser 20 at the condensation temperature of about 47[.degree.
C.] and the evaporator 70 at the evaporating temperature of about
11[.degree. C.] to process both the sensible heat (cooling
operation) and the latent heat (dehumidifying operation) of the
air-conditioned space simultaneously. Such a refrigeration cycle
apparatus requires the evaporating temperature to be set low, so
that the operation efficiency is poor.
[0186] The refrigeration cycle apparatus 100b allows the sensible
heat processing (cooling operation) and the latent heat processing
(dehumidifying operation) in the air-conditioned space to be
conducted separately. The evaporator 70 is operated only for
processing the sensible heat, so that the evaporating temperature
can be set high. The evaporating temperature conventionally set at
11[.degree. C.] may be increased to be as high as approximately
14[.degree. C.]. As a result, the refrigerant cycle efficiency may
be largely improved.
[0187] As shown in FIG. 12, the evaporating temperature is
proportional to the COP. In Embodiment 4, when the evaporating
temperature is 11[.degree. C.], the COP is approximately 3.1 ((A)
in the drawing). When the evaporating temperature is increased to
14[.degree. C.], the COP is increased up to approximately 3.3
(shown as the point (B) in the drawing). The increase in the
evaporating temperature by 3[.degree. C.] may improve the COP by
approximately 14%.
[0188] Likewise Embodiment 5, the refrigeration cycle apparatus
100b according to Embodiment 6 is not required to conduct
defrosting, and allows the evaporating temperature of the
evaporator 70 to be set high. In the present embodiment, since the
refrigerant of the first evaporating temperature lower than the air
is made to lower the temperature of the fins 45 of the heat
exchanger 41c or 41d for dehumidification/humidification on the
side of adsorbing the water and the ambient air to increase the
relative humidity so as to promote the water adsorption, it is
possible to realize a higher performance operation.
Example 7
[0189] FIG. 23 shows an exemplary structure of a refrigeration
cycle apparatus 100c according to Embodiment 7 of the present
invention. The refrigeration cycle apparatus 100c of the present
embodiment is described as, for example, but not limited to, the
air conditioning system for cooling/heating operations. Referring
to FIG. 23, since what is designated with the same reference
numerals as those described in Embodiments 4, 5 and 6 have the same
functions, explanations will be omitted.
[0190] The refrigeration cycle apparatus 100c is formed by
sequentially connecting the compressor 10, the condenser 20, the
on-off valve 32 as the first on-off valve and the on-off valve 33
as the second on-off valve that are provided in parallel, the heat
exchangers 41e and 41f for dehumidification/humidification provided
in parallel, three-way valves 38 and 39 provided in parallel, the
on-off valves 34 and 35 provided in parallel, throttle device 85,
and evaporator 70 with the refrigerant pipe 1. Here, the
refrigeration cycle apparatus 100c is also provided with the heat
exchanger 41e (a first heat exchanger) for
dehumidification/humidification and the heat exchanger 41f (a
second heat exchanger) for dehumidification/humidification that are
the heat exchanger 40 including the fin 45 which fine pores are
formed on the surface. Those two heat exchangers 41e and 41f for
dehumidification/humidification are built into the indoor unit
separately. The control unit 80b controls the three-way valves 38
and 39 to switch the refrigerant flow passage.
[0191] Likewise the refrigeration cycle apparatus 100b according to
the above Embodiment 6, the refrigerant pipe 1 is branched into the
refrigerant pipes 1c and 1d, and after connecting the on-off valve
32, the heat exchanger 41e for dehumidification/humidification, and
the three-way valve 38 with the refrigerant pipe 1c connecting the
on-off valve 33, the heat exchanger 41f for
dehumidification/humidification, and the three-way valve 39 with
the refrigerant pipe 1b, respectively, they are joined again. The
aforementioned refrigerant may be employed as the one flowing
through the refrigerant pipe 1. The refrigerant pipes 1c and 1d
include a bypass pipe 2a (a first bypass pipe) which is branched
from the refrigerant pipe 1c between the on-off valve 32 and the
heat exchanger 41e for dehumidification/humidification to join with
the refrigerant pipe 1d between the heat exchanger 41f for
dehumidification/humidification and the three-way valve 39, and a
bypass pipe 3a (a second bypass pipe) which is branched from the
refrigerant pipe 1d between the on-off valve 33 and the heat
exchanger 41f for dehumidification/humidification to join with the
refrigerant pipe 1c between the heat exchanger 41e for
dehumidification/humidification and the three-way valve 38.
[0192] The bypass pipe 3a is provided with the throttle device 63.
The bypass pipe 2a is provided with the throttle device 64. The
refrigeration cycle apparatus 100c is provided with a
temperature/humidity detection unit (not shown) for detecting the
temperature and humidity of the evaporator 70 at the inlet of the
air passage of the evaporator 70. The temperature/humidity
detection unit is not limited to the specific type so far as the
temperature and the humidity may be detected. For example, a
temperature sensor such as a thermistor, thermometer, humidity
sensor, and hygrometer may be employed.
[0193] The refrigeration cycle apparatus 100c is provided with a
control unit (not shown) for controlling the drive frequency of the
compressor 10, opening of the on-off valves 32, 33, opening of the
throttle devices 63, 64 and 85, and opening of the three-way valves
38, 39. The three-way valves 38 and 39 switch the flow of the
refrigerant flowing through the refrigerant pipes 1a and 1b to
switch the functions (adsorption and desorption) of the heat
exchangers 41e and 41f for dehumidification/humidification.
[0194] The operation of the refrigeration cycle apparatus 100c will
be described based on FIG. 23 on the assumption that the on-off
valve 32 is opened, the on-off valve 33 is closed, the heat
exchanger 41e for dehumidification/humidification is operated to
desorb the water, and the heat exchanger 41f for
dehumidification/humidification is operated to adsorb the
water.
[0195] A high temperature/pressure gaseous refrigerant compressed
by the compressor 10 flows into the condenser 20. The refrigerant
in the aforementioned state becomes the gas-liquid two-phase
refrigerant in the condenser 20 while partially releasing the heat
to the external air. The high pressure gas-liquid two-phase
refrigerant flows into the heat exchanger 41e for
dehumidification/humidification. The incoming gas-liquid two-phase
refrigerant passes through the heat transfer pipe 46 to allow the
heat exchange between the refrigerant and air and then increase the
temperature of the fins 45 and the ambient air to lower the
relative humidity. Thereby, the water adsorbed in the fin 45 is
desorbed. The gas-liquid two-phase refrigerant is liquefied into
the liquid refrigerant.
[0196] The refrigerant flowing from the heat exchanger 41e for
dehumidification/humidification has a flow direction determined by
the three-way valve 38 under the control of the control unit 80b.
If the refrigerant is controlled to flow through the bypass pipe
3a, the low pressure gas-liquid two-phase refrigerant flows into
the heat exchanger 41f for dehumidification/humidification to lower
the temperatures of the fins 45 and the ambient air like the
Embodiment 6. This makes it possible to enhance the adsorbing
performance of the heat exchanger 41f for
dehumidification/humidification. The gas-liquid two-phase
refrigerant flowing out from the heat exchanger 41f for
dehumidification/humidification is decompressed by the throttle
device 85 via the three-way valve 38, on-off valve 35, and bypass
pipe 1d, flowing into the evaporator 70 to become the low pressure
gaseous refrigerant while removing the sensible heat of the air by
the heat exchange, then being sucked by the compressor 10 to be
circulate in the refrigerant circuit. The operation of the
refrigeration cycle apparatus 100c is reversed compared with that
of the three-way valves 38 and 39 when closing the on-off valve 32,
opening the on-off valve 33, making the heat exchanger 41f for
dehumidification/humidification desorb the water, and making the
heat exchanger 41e for dehumidification/humidification adsorb the
water.
[0197] In Embodiment 7, the apparatus is provided with the
three-way valves 38, 39 to facilitate water adsorption by lowering
the temperatures of the fins 45 of the heat exchanger 41e or 41f
for dehumidification/humidification on the side of the water
adsorbtion and the ambient air to increase the relative humidity,
so that it is possible to operate the apparatus with higher
performance.
Embodiment 8
[0198] In Embodiments 4 to 7, the heat exchanger 40 according to
Embodiments 1 to 3 is applied only to the heat exchanger 41 for
dehumidification/humidification, however, it is not limited
thereto. For example, the condenser 20 and the evaporator 70 which
serve as the heat exchangers may be provided with the fin 45 for
adsorbing the water.
[0199] In Embodiments 4 to 7 as described above, two heat
exchangers 41a, 41b for dehumidification/humidification are used
for alternate desorption and adsorption, however, the number of the
heat exchangers 41 for dehumidification/humidification is not
limited.
[0200] In Embodiments 4 to 7, the compressor 10 is not limited to a
specific type. For example, the inverter compressor capable of
controlling the capacity, and the constant rate compressor which
performs the compression at a constant rate may be employed. In the
respective embodiments, a single unit of the compressor 10 is
disposed for the refrigeration cycle, however, the number of the
compressors is not limited and plural compressor may be provided.
In the aforementioned case, the control unit 80 may be configured
to execute the multiple control of as many as the provided
compressors.
Embodiment 9
[0201] In the respective embodiments, the control units 80 and 80a
control the opening of the on-off valves, drive frequency of the
compressor 10, the opening of the respective throttle devices and
the three-way valves, however, it is not limited thereto. The
control unit may be provided for each of the apparatuses. In the
respective embodiments, a single temperature/humidity detection
unit 81 is disposed at the inlet side of the air passage of the
evaporator 70, however, it is not limited thereto. For example, the
temperature detection unit and the humidity detection unit may be
separately provided, or plural units may be provided. The pressure
detection units for detecting the refrigerant pressure may be
provided adjacent to the respective apparatuses.
[0202] In the embodiments, the refrigeration cycle apparatuses 100
to 100c are applied to the refrigerator, room air-conditioner,
all-in-one air conditioning system and the like, however, it is not
limited thereto. For example, the refrigeration cycle apparatuses
100 to 100c may be applied to the refrigerated warehouse,
humidifier, humidity control unit and the like. The type of the
refrigerant, the air passage and the flow passage in the
refrigeration cycle may be determined in accordance with the
intended use and application.
* * * * *