U.S. patent application number 13/049332 was filed with the patent office on 2012-02-02 for desiccant air-conditioning system.
This patent application is currently assigned to MITSUBISHI HEAVY INDUSTRIES, LTD.. Invention is credited to Yoshie Togano, Kenji Ueda.
Application Number | 20120023988 13/049332 |
Document ID | / |
Family ID | 44936955 |
Filed Date | 2012-02-02 |
United States Patent
Application |
20120023988 |
Kind Code |
A1 |
Togano; Yoshie ; et
al. |
February 2, 2012 |
DESICCANT AIR-CONDITIONING SYSTEM
Abstract
To reduce energy consumption, a desiccant air-conditioning
system is provided with: an air supply channel 1 that supplies
outside air A1 that flows from the outside, to an object to be
air-conditioned; an exhaust channel 2 that exhausts return air A2
that flows from the object to be air-conditioned, to the outside; a
desiccant portion 10 that adsorbs moisture from the outside air A1
passing through the air supply channel 1, and that desorbs the
adsorbed moisture to the return air A2 passing through the exhaust
channel 2; a first cooling portion 31 which is installed between
the desiccant portion 10 and the object to be air-conditioned in
the air supply channel, and which cools the outside air A1; a
second cooling portion 44 which is installed between the desiccant
portion 10 and the first cooling portion 31 in the air supply
channel, and which absorbs the heat from the outside air A1 to cool
it; a heating portion 45 which is installed between the desiccant
portion 10 and the object to be air-conditioned in the exhaust
channel 2, and which heats the return air A2 up to at least the
regeneration temperature at which the desiccant portion 10 desorbs
the moisture; and a heat supplying portion 50 that supplies the
heat absorbed from the outside air A1 by the second cooling portion
44, to the heating portion 45.
Inventors: |
Togano; Yoshie; (Tokyo,
JP) ; Ueda; Kenji; (Tokyo, JP) |
Assignee: |
MITSUBISHI HEAVY INDUSTRIES,
LTD.
Tokyo
JP
|
Family ID: |
44936955 |
Appl. No.: |
13/049332 |
Filed: |
March 16, 2011 |
Current U.S.
Class: |
62/159 ;
62/238.3 |
Current CPC
Class: |
B01D 2259/4009 20130101;
B01D 53/06 20130101; F24F 3/147 20130101; Y02B 30/563 20130101;
F24F 2203/1032 20130101; B01D 53/261 20130101; F24F 2203/104
20130101; B01D 2253/3425 20130101; Y02B 30/52 20130101; F24F 12/003
20130101; B01D 2253/202 20130101; B01D 2257/80 20130101; Y02B 30/56
20130101; B01D 2258/06 20130101; B01D 2253/106 20130101; F24F
3/1423 20130101; F24F 2203/1016 20130101 |
Class at
Publication: |
62/159 ;
62/238.3 |
International
Class: |
F25D 17/04 20060101
F25D017/04; F25B 27/00 20060101 F25B027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 27, 2010 |
JP |
2010-168532 |
Claims
1. A desiccant air-conditioning system comprising: an air supply
channel that supplies outside air that flows from the outside, to
an object to be air-conditioned; an exhaust channel that exhausts
return air that flows from the object to be air-conditioned, to the
outside; a desiccant portion that adsorbs moisture from the outside
air passing through the air supply channel, and that desorbs the
adsorbed moisture to the return air passing through the exhaust
channel; a first cooling portion which is installed between the
desiccant portion and the object to be air-conditioned in the air
supply channel, and which cools the outside air; a second cooling
portion which is installed between the desiccant portion and the
first cooling portion in the air supply channel, and which absorbs
the heat from the outside air to cool it; a heating portion which
is installed between the desiccant portion and the object to be
air-conditioned in the exhaust channel, and which heats the return
air up to at least the regeneration temperature at which the
desiccant portion desorbs the moisture; and a heat supplying
portion that supplies the heat absorbed from the outside air by the
second cooling portion, to the heating portion.
2. A desiccant air-conditioning system according to claim 1,
comprising a sensible heat exchange portion that exchanges heat
between the outside air in the air supply channel between the
desiccant portion and the second cooling portion, and the return
air in the exhaust channel between the heating portion and the
object to be air-conditioned.
3. A desiccant air-conditioning system according to claim 1 or
claim 2, comprising a control portion that increases and decreases
the amount of heat supplied to the heating portion in proportion to
the latent heat load of the object to be air-conditioned.
4. A desiccant air-conditioning system according to claim 3,
wherein the second cooling portion increases and decreases the
amount of heat absorbed from the outside air according to the
amount of heat to be supplied, and the control portion cools the
outside air in the first cooling portion such that the outside air
to be supplied to the object to be air-conditioned reaches a target
supply air temperature.
5. A desiccant air-conditioning system according to claim 1,
wherein the heat supplying portion further comprises: a
high-temperature heat transfer medium circuit, which is connected
to the heating portion, and through which a high-temperature heat
transfer medium that has a relatively high temperature circulates;
a low-temperature heat transfer medium circuit, which is connected
to the second cooling portion, and through which a low-temperature
heat transfer medium that has a relatively low temperature
circulates; and a heat pump that moves the heat of the
low-temperature heat transfer medium to the high-temperature heat
transfer medium.
6. A desiccant air-conditioning system according to according to
claim 1, comprising: a pre-cooling portion that cools the outside
air, which is installed between the desiccant portion and the
outside in the air supply channel; a header that connects the
pre-cooling portion and the first cooling portion; and a
centrifugal chiller that can supply chilled water to at least one
of the pre-cooling portion and the first cooling portion.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a desiccant
air-conditioning system.
[0003] Priority is claimed on Japanese Patent Application No.
2010-168532, filed Jul. 27, 2010, the content of which is
incorporated herein by reference.
[0004] 2. Description of Related Art
[0005] As is widely known, the air-conditioning load of a building
comprises a sensible heat load and a latent heat load. Roughly, in
the air-conditioning load, the ratio of the sensible heat load to
the latent heat load is approximately 8:2. Consequently, in an
attempt toremove the air-conditioning load by heat exchange between
the air in the building and a heat transfer medium, the temperature
of the heat transfer medium must be further lowered by the amount
of the latent heat load, which increases the energy consumption.
Therefore, in recent years, desiccant air-conditioning systems, in
which the latent heat load is removed after the sensible heat load
is removed with a desiccant (hygroscopic material), has been widely
used as described in the Patent Document 1.
[0006] One of the desiccant systems includes: an air supply channel
that supplies outside air flowing from the outside to the inside of
a building; an exhaust channel that exhausts return air flowing
from the inside of the building to the outside; a desiccant portion
that adsorbs moisture from the outside air passing through the air
supply channel and desorbs the adsorbed moisture to the return air
passing through the exhaust channel; a cooling portion, which is
placed between the desiccant portion and an object to be
air-conditioned, in the air supply channel, and cools the outside
air; and a heating portion that heats the return air up to a
regeneration temperature at which the desiccant portion desorbs the
moisture.
PRIOR ART DOCUMENT
Patent Document
[0007] [Patent Document 1] Japanese Unexamined Patent Application,
First Publication No. 2006-189189
SUMMARY OF INVENTION
Problems to be Solved by the Invention
[0008] In the conventional technique, the outside air is cooled in
the cooling portion that supplies the air, and afterwards the
return air is heated up to the regeneration temperature of the
desiccant portion. Therefore cooling and heating of the flowing air
are needed, energy being spent doubly, which is inefficient.
[0009] The present invention has been made in consideration of the
above circumstances, with an object of reducing the energy
consumption of a desiccant air-conditioning system.
Means for Solving the Problem
[0010] In order to achieve the above-described object, the present
invention adopts the following means.
[0011] That is, a desiccant air-conditioning system according to
the first aspect of the present invention includes: an air supply
channel that supplies outside air that flows from the outside, to
an object to be air-conditioned; an exhaust channel that exhausts
return air that flows from the object to be air-conditioned, to the
outside; a desiccant portion that adsorbs moisture from the outside
air passing through the air supply channel, and that desorbs the
adsorbed moisture to the return air passing through the exhaust
channel; a first cooling portion which is installed between the
desiccant portion and the object to be air-conditioned in the air
supply channel, and which cools the outside air; a second cooling
portion which is installed between the desiccant portion and the
first cooling portion in the air supply channel, and which absorbs
the heat from the outside air to cool it; a heating portion which
is installed between the desiccant portion and the object to be
air-conditioned in the exhaust channel, and which heats the return
air up to at least the regeneration temperature at which the
desiccant portion desorbs the moisture; and a heat supplying
portion that supplies the heat absorbed from the outside air by the
second cooling portion, to the heating portion.
[0012] According to this configuration, since the second cooling
portion has a heat supplying portion that supplies heat absorbed
from the outside air to the heating portion, the heat from the
outside air passing through the air supply channel is transferred
to the return air passing through the exhaust channel. This reduces
the amount of heat (specific enthalpy difference) handled by the
first cooling portion, energy used by the first cooling portion can
be reduced, and thus energy consumption can be reduced. In
addition, since the heat is supplied from the second cooling
portion to the heating portion, energy required for heating can be
reduced, compared to using a high-temperature heat source such as a
boiler or the like.
[0013] Thus, it is possible to reduce the energy consumption of the
overall air-conditioning system.
[0014] The desiccant air-conditioning system according to the first
aspect of the present invention may further includes, a sensible
heat exchange portion that exchanges heat between the outside air
in the air supply channel between the desiccant portion and the
second cooling portion, and the return air in the exhaust channel
between the heating portion and the object to be
air-conditioned.
[0015] According to this configuration, since it is provided with
the sensible heat exchange portion that exchanges heat between the
outside air and the return air, heat exchange is performed in
advance by the heat supplying portion, before heat is transferred
from the outside air to the return air. Because of this, the amount
of heat to be transferred by the heat supplying portion can be
reduced, energy used for the heat supplying portion can be reduced,
so that the energy consumption can be further reduced.
[0016] The desiccant air-conditioning system according to the first
aspect of the present invention may further includes, a control
portion that increases and decreases the amount of heat supplied to
the heating portion in proportion to the latent heat load of the
object to be air-conditioned.
[0017] According to this configuration, since the amount of heat
supplied to the heating portion is increased and decreased in
proportion to the latent heat load, excessive heat supply with
respect to the latent heat load can be prevented, and energy used
for the heat supplying portion can be reduced. As a result, the
energy consumption can be further reduced.
[0018] In the desiccant air-conditioning system according to the
first aspect of the present invention may further includes, the
second cooling portion may increase and decrease the amount of heat
absorbed from the outside air according to the amount of heat to be
supplied, and the control portion may cool the outside air in the
first cooling portion such that the outside air to be supplied to
the object to be air-conditioned reaches a target supply air
temperature.
[0019] According to this configuration, since the outside air is
cooled by the first cooling portion to adjust the temperature of
the supply air to the target supply air temperature, energy used
for the second cooling portion can be reduced appropriately in
accordance with the amount of heat supplied to the heating portion,
and the temperature of the outside air can be adjusted to the
target supply air temperature securely.
[0020] In the desiccant air-conditioning system according to the
first aspect of the present invention, the heat supplying portion
may further comprises: a high-temperature heat transfer medium
circuit, which is connected to the heating portion, and through
which a high-temperature heat transfer medium that has a relatively
high temperature circulates; a low-temperature heat transfer medium
circuit, which is connected to the second cooling portion, and
through which a low-temperature heat transfer medium that has a
relatively low temperature circulates; and a heat pump that moves
the heat of the low-temperature heat transfer medium to the
high-temperature heat transfer medium.
[0021] According to this configuration, it is possible to provide a
desiccant air-conditioning system with a relatively simple system
configuration.
[0022] The desiccant air-conditioning system according to the first
aspect of the present invention may further includes: a pre-cooling
portion that cools the outside air, which is installed between the
desiccant portion and the outside in the air supply channel; a
header that connects the pre-cooling portion and the first cooling
portion; and a centrifugal chiller that can supply chilled water to
at least one of the pre-cooling portion and the first cooling
portion.
EFFECTS OF THE INVENTION
[0023] According to the desiccant air-conditioning system of the
present invention, it is possible to reduce energy consumption.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a schematic structural diagram of a desiccant
air-conditioning system 51 according to a first embodiment of the
present invention.
[0025] FIG. 2 is a psychrometric chart showing the change in state
of air in the desiccant air-conditioning system 51 according to the
first embodiment of the present invention.
[0026] FIG. 3 is a schematic structural diagram of a desiccant
air-conditioning system C, which is a comparative example of the
desiccant air-conditioning system 51. The numbers with parentheses
correspond to spaces in channels as explained in FIG. 1.
[0027] FIG. 4 is a psychrometric chart showing the change in state
of air in the desiccant air-conditioning system C, which is a
comparative example of the desiccant air-conditioning system 51.
Symbols with numbers corresponding to spaces in channels are shown
as explained in the FIG. 2.
[0028] FIG. 5 is a schematic structural diagram showing a desiccant
air-conditioning system S2 according to a second embodiment of the
present invention. The numbers with parentheses correspond to
spaces in channels as explained in FIG. 1.
[0029] FIG. 6 is a diagram for explaining the operation of the
desiccant air-conditioning system S2 according to the second
embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0030] Hereunder is a description of embodiments of the present
invention, with reference to the drawings.
[0031] FIG. 1 is a schematic structural diagram of a desiccant
air-conditioning system 51 according to a first embodiment of the
present invention.
[0032] As shown in FIG. 1, the desiccant air-conditioning system 51
has; an air supply channel 1, an exhaust channel 2, a desiccant
portion 10, a sensible heat exchange device (sensible heat exchange
portion) 20, a refrigeration unit 30, a heat exchange unit 40, a
control portion 60, and a sensor portion 70.
[0033] The air supply channel 1 supplies outside air A1 flowing
from the outside to the inside of a room (an object to be
air-conditioned). The outside air A1 is sucked in by the first
ventilation fan 3 through an outside opening 1a, supplying the
outside air A1 to the inside of the room through a room side
opening 1b.
[0034] The exhaust channel 2 exhausts return air A2 flowing from
the inside of the room to the outside. The return air A2 is sucked
in by the second ventilation fan 4 through a room side opening 2b,
exhausting the return air A2 through an outside opening 2a to the
outside. The exhaust channel 2 is provided in parallel with the air
supply channel 1.
[0035] The desiccant portion 10 is rotatable. It comprises a disk
shaped rotor member (not shown in the figure) having a bundle of
honeycomb shaped passages, and a silica gel type adsorbent or a
polymer sorbent soaked into the surfaces of the honeycomb shaped
passages of the rotor member. The desiccant portion 10 extends
between the air supply channel 1 and the exhaust channel 2. The
return air A2 and the outside air A1 pass through the honeycomb
shaped passages. By rotating the rotor member, locations of the
honeycomb shaped passages are alternated between the air supply
channel 1 and the exhaust channel 2.
[0036] The desiccant portion 10 adsorbs the moisture contained in
the outside air A1 on the surfaces of the honeycomb shaped passages
as it passes through the passages in the air supply channel 1. By
rotating the rotor member, the honeycomb shaped passages in which
the moisture is adsorbed, are positioned in the exhaust channel 2,
and the adsorbed moisture is desorbed to the return air A2 passing
through the honeycomb shaped passages.
[0037] The sensible heat exchange device 20 exchanges heat between
the outside air A1, which is in the air supply channel 1 and
between the desiccant portion 10 and a second cooling coil 44
(described later), and the return air A2, which is in the exhaust
channel 2 and between a regeneration heating coil 45 (described
later) and the room.
[0038] The sensible heat exchange device 20 is rotatable. It
comprises a honeycomb rotor of a form in which aluminum sheets are
processed into a corrugated form, and are rolled up into a
cylinder. The sensible heat exchange device 20 extends between the
air supply channel 1 and the exhaust channel 2. The return air A2
and the outside air A1 pass through the honeycomb rotor. The
outside air A1 passes through the sensible heat exchange device 20
after being dehumidified (after passing through the desiccant
portion 10) in the air supply channel 1, absorbs heat contained in
the passing outside air A1, and forms a heat storage portion in
part of the sensible heat exchange device 20. Afterwards, by being
rotated, the heat storage portion is positioned in the exhaust
channel 2, and transfers the heat to the return air A2 passing
through the heat storage portion.
[0039] The refrigeration unit 30 generally comprises: a first
cooling coil (first cooling portion) 31 that absorbs heat from the
outside air A1; a centrifugal chiller 32 that cools the first
cooling coil 31; a cooling tower 33 releasing the heat that the
first cooling coil 31 absorbed from the centrifugal chiller 32; a
pump 34a that pumps chilled water between the first cooling coil 31
and the centrifugal chiller 32; and a pump 34b that pumps cooling
water between the centrifugal chiller 32 and the cooling tower
33.
[0040] The refrigeration unit 30 is controlled by the control
portion 60 such that the outside air A1 flowing into the first
cooling coil 31 is cooled to a predetermined target supply air
temperature.
[0041] The heat exchange unit 40 generally comprises: a heat
supplying portion 50 which includes a hot water heat pump (heat
pump) 41, a hot water circuit (high temperature heating medium
circuit) 42, and a heat source water circuit (low temperature
heating medium circuit) 43; the second cooling coil (second cooling
portion) 44; and the regeneration heating coil (heating portion)
45.
[0042] The hot water heat pump 41 has a compressor 41a that
compresses a refrigerant, a condenser 41b that cools the compressed
refrigerant to condense it, an expansion valve 41c that expands the
condensed refrigerant, and an evaporator 41d that evaporates the
expanded refrigerant. The hot water heat pump 41 can supply chilled
water (heat source water) and hot water at the same time.
[0043] The condenser 41b and the evaporator 41d are
refrigerant-to-water heat exchangers, and can be general plate heat
exchangers or double tube heat exchangers.
[0044] The hot water circuit 42 is connected to the regeneration
heating coil 45 and the hot water heat pump 41, and circulates hot
water between the regeneration heating coil 45 and the hot water
heat pump 41. The hot water of the hot water circuit 42 transfers
the heat received from the refrigerant to the regeneration heating
coil 45 via the condenser 41b of the hot water heat pump 41.
[0045] The heat source water circuit 43 is connected to the second
cooling coil 44 and the hot water heat pump 41, and circulates low
temperature heat source water between the second cooling coil 44
and the hot water heat pump 41. The heat source water of the heat
source water circuit 43 transfers the heat received from the second
cooling coil 44 to the refrigerant via the evaporator 41d.
[0046] The second cooling coil 44 is kept at a low temperature by
the heat source water circulating in the heat source water circuit
43, and absorbs heat from the outside air A1 passing through the
sensible heat exchange device 20 and cools the outside air A1. In
other words, the second cooling coil 44 uses the evaporator 41d of
the hot water heat pump 41 as a low temperature heat source.
[0047] Heat is supplied to the regeneration heating coil 45 by hot
water circulating through the hot water circuit 42. In other words,
the regeneration heating coil 45 uses the condenser 41b of the hot
water heat pump 41 as a high temperature heat source.
[0048] By having the configuration described above, in the heat
exchange unit 40, the heat absorbed by the second cooling coil 44
from the outside air A1 is transferred to the heat source water.
Then, after the heat of the heat source water, which is absorbed by
the evaporator 41d of the hot water heat pump 41, is transferred to
the refrigerant, the heat of the refrigerant is transferred to the
hot water by the condenser 41b, and supplied to the regeneration
heating coil 45.
[0049] Furthermore, the amount of heat supplied to the regeneration
heating coil 45 is controlled by the control portion 60 such that
it increases and decreases in proportion to the latent heat
load.
[0050] "The amount of heat supplied" means the amount of heat
supplied per unit mass (the same definition applies hereunder).
[0051] The sensor portion 70 detects the dry-bulb temperature and
the absolute humidity of the outside air A1, and outputs them to
the control portion 60.
[0052] A sensor portion 71 detects the absolute humidity of the
return air A2, and outputs it to the control portion 60.
[0053] The control portion 60 controls the temperature of the
return air A2 to be kept within a range of regeneration temperature
(refer to FIG. 2), and increases and decreases the amount of heat
supplied to the regeneration heating coil 45 in proportion to the
latent heat load. In the present embodiment, the lower limit of the
regeneration temperature is set to the desorption temperature of
the hygroscopic material, and the upper limit is set to a
temperature below that which the hot water heat pump 41 can supply
(for example, 90.degree. C.). The upper limit of the regeneration
temperature may be set to a temperature at which the structure of
the hygroscopic material does not change.
[0054] The processing of the control portion 60 is described in
more detail below. The control portion 60 calculates the difference
between a preset target absolute humidity and the absolute humidity
of the outside air A1 input from the sensor portion 70, as a latent
heat load. Here the latent heat load processing capability
(absorption and desorption capabilities) of the desiccant portion
10 is determined mainly by the following elements: the dry-bulb
temperature and the absolute humidity at the inlet of the desiccant
portion in the air supply channel 1, and the dry-bulb temperature
and the absolute humidity at the inlet of the desiccant portion in
the exhaust channel 2. The control portion 60 calculates the
dry-bulb temperature at the inlet of the desiccant portion in the
exhaust channel 2 corresponding to the calculated latent heat load,
from the relationship between the latent heat load and each of the
elements (a mathematical function between the latent heat load and
each of the elements, or a table in which the latent heat load and
each of the elements are associated), using in addition to the
latent heat load, the dry-bulb temperature and the absolute
humidity of the outside air A1 input from the sensor portion 70
(equal to the dry-bulb temperature and the absolute humidity at the
inlet of the desiccant portion in the air supply channel 1), and
the absolute humidity of the return air A2 at the outlet E of the
sensible heat exchange device in the exhaust channel 2, which is
input from the sensor portion 71 (equal to the absolute humidity at
the inlet of the desiccant portion in the exhaust channel 2).
[0055] Then, it calculates the temperature of the hot water
supplied to the regeneration heating coil 45, from the dry-bulb
temperature of the return air A2 at the outlet E of the sensible
heat exchange device in the exhaust channel 2, which is input from
the sensor portion 71, and the dry-bulb temperature at the inlet of
the desiccant portion in the exhaust channel 2. Then it controls
the heat supplying portion 50 to adjust the temperature of the hot
water supplied to the regeneration heating coil 45. In this case,
the amount of heat that the second cooling coil 44 absorbs from the
outside air A1 increases and decreases correlating with the change
of the temperature of the hot water, in other words, the increase
and decrease of the amount of heat supplied to the regeneration
heating coil 45.
[0056] Next is a description of the operation of the desiccant
air-conditioning system S1 of the above-described configuration,
with reference to the drawings.
[0057] First, the operation of the control portion 60 will be
described.
[0058] The control portion 60 controls the amount of heat supplied
to the regeneration heating coil 45 from the hot water heat pump 41
such that the temperature of the return air A2 is kept within the
regeneration temperature range. At the same time, the control
portion 60 increases and decreases the amount of heat supplied in
proportion to the latent heat load. To be specific, by controlling
the amount of heat exchanged between the hot water and the heat
source water, and the temperature and the flow rate of the hot
water, the control portion 60 controls the amount of heat supplied
to the regeneration heating coil 45. For example, in the case where
the latent heat load drops from L11 to L12, only a smaller amount
of heat is required to regenerate the desiccant portion 10.
Therefore the amount of heat supplied is reduced from Qh2 to Qh3
(refer to FIG. 2).
[0059] Then, the hot water heat pump 41 supplies the heat absorbed
from the outside air A1 by the second cooling coil 44, to the
regeneration heating coil 45 according to the heat supply amount
under the control of the control portion 60 (refer to FIG. 2).
[0060] Then, the control portion 60 controls the first cooling coil
31 and lets the first cooling coil 31 to absorb heat from the
outside air A1 after the second cooling coil 44 has absorbed the
heat, cooling the outside air A1 to the target supply air
temperature.
[0061] Next, the state of the outside air A1 and the return air A2
in the desiccant air-conditioning system S1 will be described,
focusing on the flow of the outside air A1 and the return air
A2.
[0062] In FIG. 1, the reference symbols (1) to (4) indicate spaces
in the supply channel 1. (1) represents a space between outside
opening 1a and the desiccant portion 10. (2) represents a space 1
between the desiccant portion 10 and the sensible heat exchange
portion 20. (3) represents a space between the sensible heat
exchange portion 20 and the second cooling coil 44. (3)' represents
a space between the second cooling coil 44 and the first cooling
coil 31. (4) represents a space between the first cooling coil 31
and the room side opening 1b.
[0063] In addition, the reference symbols (5) to (8) in FIG. 1
indicate spaces in the exhaust channel 2. (5) represents a space
between the sensible heat exchange portion 20 and the room side
opening 2b. (6) represents a space between the regeneration heating
coil 45 and the sensible heat exchange portion 20. (7) represents a
space between the desiccant portion 10 and the regeneration heating
coil 45. (8) represents a space between the outside opening 2a and
the desiccant portion 10.
[0064] FIG. 2 is a psychrometric chart showing the change of state
of the air in the desiccant air-conditioning system S1.
[0065] In FIG. 2, symbols (open triangles and closed diamonds) with
the reference symbols (1) to (8) represent absolute humidity and
dry-bulb temperature at the spaces (1) to (8) as described
above.
[0066] Firstly, as shown in FIG. 1, when the outside air A1 flowing
from the outside opening 1a to the air supply channel 1 passes
through the desiccant portion 10 (from the space (1) to the space
(2)), the moisture of the outside air A1 is adsorbed on the
surfaces of the honeycomb shaped passages, and as shown in FIG. 2,
the absolute humidity drops. Furthermore, the honeycomb shaped
passages in the air supply channel 1 are regenerated by the return
air A2 whose temperature is higher than the outside air A1 in the
exhaust channel 1, so the temperature is higher than the outside
air A 1. As a result, in the air supply channel 1, when the outside
air A1 passes through the desiccant portion 10 (honeycomb shaped
passages), the dry-bulb temperature of the outside air A1 increases
(from the symbol corresponding to the space (1) to (2)).
[0067] For example, by passing through the desiccant portion 10,
the absolute humidity of the outside air A1 drops from 15 g/kg(DA)
to 9 g/kg(DA), and the dry-bulb temperature increases from
29.degree. C. to 49.degree. C.
[0068] Next, as shown in FIG. 1, when the outside air A1 passes
through the sensible heat exchange device 20 (from the space (2) to
the space (3)), as shown in FIG. 2, the outside air A1 has its heat
absorbed by the sensible heat exchange device 20 and is cooled. For
example, by passing through the sensible heat exchange device 20,
the dry-bulb temperature drops from 49.degree. C. to 34.degree.
C.
[0069] Next, as shown in FIG. 1, when the outside air A1 passes
through the second cooling coil 44 (from the space (3) to the space
(3)'), as shown in FIG. 2, the outside air A1 has its heat absorbed
by the second cooling coil 44, and is cooled. That is, as described
above, the outside air A1 is cooled by the amount of the absorbed
heat determined according to the heat supply amount under the
control of the control portion 60.
[0070] For example, by passing through the second cooling coil 44,
the dry-bulb temperature drops from 34.degree. C. to 26.degree.
C.
[0071] Next, as shown in FIG. 1, when the outside air A1 passes
through the first cooling coil 31 (from the space (3)' to the space
(4)), as shown in FIG. 2, the outside air A1 has its heat absorbed
by the first cooling coil 31, and is cooled. That is, as described
above, the control portion 60 cools the outside air A1 by the first
cooling coil 31, taking the outside air A1 to the set target supply
air temperature.
[0072] For example, by passing through the first cooling coil 31,
the dry-bulb temperature drops from 26.degree. C. to 18.degree.
C.
[0073] At this time, the amount of heat (specific enthalpy
difference) that the first cooling coil 31 handles is reduced by
the amount of the absorbed heat handled by the second cooling coil
44 (Qc2.fwdarw.Qc3). Therefore the energy required for the
centrifugal chiller 32 is reduced compared to a configuration
without the second cooling coil 44.
[0074] In this way, the outside air A1 is supplied to the room
after reaching to the target supply air temperature.
[0075] Next, as shown in FIG. 1, when the return air A2 that flows
from the room into the exhaust channel 2 via the room side opening
2b passes through the sensible heat exchange device 20 (from the
space (5) to the space (6)), as shown in FIG. 2, the return air A2
receives heat from the sensible heat exchange device 20, and is
heated. For example, by passing through the sensible heat exchange
device 20, the dry-bulb temperature increases from 28.degree. C. to
44.degree. C. Due to passing through inside the room, the
temperature of the return air A2 increases from the dry-bulb
temperature 18.degree. C. (supply air temperature) to the dry-bulb
temperature 28.degree. C.
[0076] Next, as shown in FIG. 1, when the return air A2 passes
through the regeneration heating coil 45 (from the space (6) to the
space (7)), as shown in FIG. 2, the return air A2 receives heat
from the regeneration heating coil 45, and is heated. For example,
by the return air A2 passing through the regeneration heating coil
45, the temperature increases from the thy-bulb temperature
44.degree. C. to the dry-bulb temperature 56.degree. C.
[0077] Next, as shown in FIG. 1, when the return air A2 passes
through the desiccant portion 10 (from the space (7) to the space
(8)), it absorbs moisture from the desiccant portion 10 so that the
absolute humidity of the return air A2 increases as shown in FIG.
2. Furthermore, since the honeycomb shaped passages in the exhaust
channel 2 had passed the outside air A1 in the air supply channel 1
with a lower temperature than the return air A2, their temperature
is lower than the return air A2. As a result, when the return air
A2 passes through the desiccant portion 10 (honeycomb shaped
passages) in the exhaust channel 2, the dry-bulb temperature of the
return air A2 drops (from the symbol corresponding to the space (7)
to (8)).
[0078] For example, by passing through the desiccant portion 10,
the absolute humidity of the return air A2 increases from 9
g/kg(DA) to 17 g/kg(DA), and the dry-bulb temperature drops from
56.degree. C. to 39.degree. C.
[0079] Then, this return air A2 is exhausted to the outside.
[0080] As described above, according to the desiccant
air-conditioning system S1, the second cooling coil 44 supplies the
heat absorbed from the outside air A1, to the regeneration heating
coil 45. Therefore the heat of the outside air A1 passing through
the air supply channel 1 is transferred to the return air A2 that
passes through the exhaust channel 2. This reduces the amount of
heat (specific enthalpy difference) that is handled by the first
cooling coil 31 (Qc2.fwdarw.Qc3), so that it is possible to reduce
the energy required for the centrifugal chiller 32, and thus enable
the energy consumption to be reduced. Moreover, heat is supplied
from the second cooling coil 44 to the regeneration heating coil
45. Therefore compared to a case in which a high-temperature heat
source such as a boiler or the like is used, the energy required
for heating can be reduced.
[0081] FIG. 3 shows a desiccant air-conditioning system C, being a
comparative example of a desiccant air-conditioning system S1, and
FIG. 4 is a psychrometric chart showing the change in state of the
air in the desiccant air-conditioning system C.
[0082] The reference symbols indicating spaces in the channels are
the same to symbols used in FIG. 1, except for (3)'' representing
the space in the supply channel 1 between the sensible heat
exchange device 20 and the first cooling coil 31.
[0083] As shown in FIG. 3, the configuration of the desiccant
air-conditioning system C is such that the heat supplying portion
50 is omitted from the configuration of the desiccant
air-conditioning system S1, and a boiler B is provided as a heat
source for the regeneration heating coil 45. In FIG. 3 and FIG. 4,
the same reference symbols are used for the same structural
elements as in FIG. 1 and FIG. 2, and their descriptions are
omitted.
[0084] As shown in FIG. 4, the desiccant air-conditioning system C
cools the outside air A1 that has passed through the sensible heat
exchange device 20, to the target supply air temperature (from the
space (3)'' to the space (4)). Therefore the amount of heat
(specific enthalpy difference) Qc2 must be handled only by the
refrigeration unit 30. Whereas, as shown in FIG. 2, after the
outside air A1 that has passed through the sensible heat exchange
device 20 has been cooled by the second cooling coil 44 (from the
symbol corresponding to the space (3) to (3)'), the desiccant
air-conditioning system S1 cools it to the target supply air
temperature by the refrigeration unit 30 (from the symbol
corresponding to the space (3)' to (4)). Therefore the amount of
heat (specific enthalpy difference) handled by the refrigeration
unit 30 is reduced from Qc2 to Qc3. This enables the energy
required for the centrifugal chiller 32 to be reduced, so that it
is possible to reduce the amount of energy consumed.
[0085] On the other hand, since the heat exchange unit 40 can
transfer a large amount of heat using comparatively low power, it
can reduce the energy required for heating compared to the
desiccant air-conditioning system C using the boiler B.
[0086] Therefore, it is possible to reduce the energy consumption
of the overall air-conditioning system.
[0087] Furthermore, a heat exchange device 20 is provided that
exchanges heat between the outside air A1 and the return air A2.
Therefore heat exchange is performed in advance at an earlier stage
than when heat is transferred from the outside air A1 to the return
air A2. Because of this, it is possible to reduce the amount of
heat to be transferred in the heat exchange unit 40, reducing the
energy required for the hot water heat pump 41, so that the energy
consumption of the overall air-conditioning system can be further
reduced.
[0088] Moreover, the amount of heat supplied to the regeneration
heating coil 45 is increased and decreased in proportion to the
latent heat load. Therefore it is possible to prevent the amount of
heat supplied from being excessive with respect to the latent heat
load, and also to reduce the energy require for the hot water heat
pump 41. As a result, the energy consumption can be further
reduced.
[0089] For example, when the latent heat load is reduced, the
moisture that is adsorbed from the outside air A1 by the desiccant
portion 10 is reduced, so that only a small amount of heat is
required to regenerate the desiccant portion 10. In this case, if a
fixed amount of heat Qh2 is supplied to the regeneration heating
coil 45, the amount of heat supplied becomes excessive with respect
to the latent heat load.
[0090] In general, most of the energy consumption of a hot water
heat pump and a centrifugal chiller is the energy used for the
compressor for increasing the pressure from evaporator pressure to
condenser pressure. Therefore, it is important to reduce this
difference (in the case of a hot water heat pump, it is the
difference between the heat source water outlet temperature and the
hot water outlet temperature, and in the case of a centrifugal
chiller, it is the difference between the chilled water outlet
temperature and the cooling water outlet temperature) in order to
reduce the energy consumption.
[0091] Supposing that, in the desiccant air-conditioning system S1,
the amount (hot water supply temperature) of heat supplied to the
regeneration heating coil 45 became excessive relative to the
latent heat load, then regardless of the margin for reducing the
difference between the heat source water outlet temperature and the
hot water outlet temperature in the hot water heat pump 41, the
compressor 41a of the hot water heat pump 41 has to work to
compensate the excessively, and thus it must consume extra energy.
Similarly, if the amount (chilled water supply temperature) of heat
absorbed in the first cooling coil 31 was kept constant regardless
of the scale of the latent heat load, the compressor of the
centrifugal chiller 32 has to work by the margin for reducing the
difference between the chilled water outlet temperature and the
cooling water outlet temperature of the centrifugal chiller 32, and
thus extra energy is consumed.
[0092] According to the desiccant air-conditioning system 51, as
shown in FIG. 2, in the case where the latent heat load is reduced,
the amount of heat supplied is reduced from Qh2 to Qh3, reducing
the difference between the heat source water outlet temperature and
the hot water outlet temperature. Therefore it is possible to
reduce the energy required for the compressor 41a of the hot water
heat pump 41, so that the amount of energy consumed can be
reduced.
[0093] Furthermore, the outside air A1 is cooled by the first
cooling coil 31 such that it reaches the target supply air
temperature. Therefore it is possible to take the outside air A1 to
the target supply air temperature accurately while controlling the
energy required for the centrifugal chiller 32 that cools the
second cooling coil 44 appropriately according to the amount of
heat supplied to the regeneration heating coil 45.
[0094] Moreover, with the configuration of the heat exchange unit
40, it is possible to make a comparatively simple system
structure.
[0095] Next is a description of a desiccant air-conditioning system
S2 according to a second embodiment of the present invention, with
reference to FIG. 5. FIG. 5 is a schematic structural diagram of
the desiccant air-conditioning system S2. The reference symbols
indicating spaces in the channels in FIG. 5 are the same to symbols
used in FIG. 1, except for (1)' representing the space in the
supply channel 1 between the outside opening 1a and the pre-cooling
coil 36, and (1)'' representing the space in the supply channel 1
between the pre-cooling coil 36 and the desiccant portion 10. For
other reference symbols in FIG. 5, the same reference symbols are
used for the same structural elements as in FIG. 1 to FIG. 4, and
their descriptions are omitted.
[0096] As shown in FIG. 5, the desiccant air-conditioning system S2
comprises a pre-cooling coil (pre-cooling portion) 36 which is
placed between the desiccant portion 10 and the outside in the air
supply channel 1 and cools the outside air A1, and a header 35 that
connects the pre-cooling coil 36 and the first cooling coil 31. The
centrifugal chiller 32 can supply chilled water to the pre-cooling
coil 36 and the first cooling coil 31.
[0097] In this configuration, the COP (coefficient of performance)
of the centrifugal chiller 32 becomes higher than the COP of the
hot water heat pump 41.
[0098] In the above-described first embodiment, the configuration
is such that the adsorption and desorption of the desiccant portion
10 is controlled by the regeneration temperature. However, in the
present embodiment, the pre-cooling coil 36 is placed immediately
in front of the desiccant portion 10 in the air supply channel, and
by controlling the outside air temperature, the adsorption and
desorption of the desiccant portion 10 is controlled, and the
regeneration temperature of the desiccant portion 10 is further
lowered.
[0099] As described above, the ability of the desiccant portion 10
to handle the latent heat load is determined mainly by the dry-bulb
temperature and the absolute humidity at the inlet of the desiccant
portion in the air supply channel 1, and the dry-bulb temperature
and the absolute humidity at the inlet of the desiccant portion in
the exhaust channel 2. Therefore, by lowering the dry-bulb
temperature at the inlet of the desiccant portion in the air supply
channel 1 using the pre-cooling coil 36, it is possible to lower
the dry-bulb temperature at the inlet of the desiccant portion in
the exhaust channel 2.
[0100] For example, the upper threshold value of the temperature of
the hot water supplied to the regeneration heating coil 45 is set
differently from the technical upper threshold value (upper
threshold value of the temperature that can be set technically).
When the temperature of the hot water supplied to the regeneration
heating coil 45, which has been obtained by the above-mentioned
procedure, exceeds the set upper threshold value, the dry-bulb
temperature at the inlet of the desiccant portion in the air supply
channel 1, which allows to keep the temperature of the hot water
supplied to the regeneration heating coil 45 to the set upper
threshold value, is calculated. In other words, the amount of
cooling heat required is calculated from the calculated dry-bulb
temperature at the inlet of the desiccant portion in the air supply
channel 1, and the dry-bulb temperature at the inlet of the outside
air A1, which is input from the sensor portion 70. Then, the amount
of cooling heat is supplied to the pre-cooling coil 36 from the
centrifugal chiller 32.
[0101] The temperature of the outside air A1 after pre-cooling
seldom goes below the supply air temperature, so the temperature of
the chilled water supplied to the pre-cooling coil 36 may be the
same as the temperature of the chilled water in the first cooling
coil 31.
[0102] In this state, the dry-bulb temperatures (.degree. C.) and
absolute humidity (g/kg) at spaces (1) to (8), which are shown in
FIG. 5, are, for example: 28.degree. C. and 15 g/kg at the space
(1)'; 19.degree. C. and 13 g/kg at the space (1)''; 41.degree. C.
and 9 g/kg at the space (2); 28.degree. C. and 9 g/kg at the space
(3); 18.degree. C. and 9 g/kg at the space (4); 28.degree. C. and 9
g/kg at the space (5); 38.degree. C. and 9 g/kg at the space (6);
60.degree. C. and 9 g/kg at the space (7); and 38.degree. C. and 16
g/kg at the space (8).
[0103] Furthermore, in the pre-cooling coil 36, the temperature of
the inflow chilled water is 15.degree. C. and the temperature of
the outflow chilled water is 20.degree. C., in the first cooling
coil 31 the temperature of the inflow chilled water is 21.degree.
C. and the temperature of the outflow chilled water is 26.degree.
C., in the second cooling coil 44 the temperature of the inflow
chilled water is 15.degree. C. and the temperature of the outflow
chilled water is 20.degree. C., and in the regeneration heating
coil 45 the temperature of the inflow hot water is 63.degree. C.
and the temperature of the outflow hot water is 53.degree. C.
[0104] According to this configuration, it is possible to lower the
temperature of the hot water supplied to the regeneration heating
coil 45, reducing the energy consumption of the hot water heat pump
41, so that it is possible to improve the COP of the hot water heat
pump 41. Moreover, by the amount of heat required to handle the
latent heat load being distributed to the centrifugal chiller 32
with high COP, compared to the hot water heat pump 41, it is
possible to further reduce the energy consumption of the overall
system. In other words, as shown in FIG. 6, by supplying the amount
of heat required to handle the latent heat load using not only the
hot water heat pump 41, but also the centrifugal chiller 32, it is
possible to reduce the energy consumption even further.
[0105] The operating procedures shown in the above-described
embodiments, the various configurations, the combinations, and the
like, are examples. Any change or modification is possible based on
design requirements and the like provided it does not depart from
the gist of the present invention.
[0106] For example, in the above-described embodiments, the
sensible heat exchange device 20 is rotatable. However, having the
sensible heat exchange device 20 to be static, and a channel
switching system may be used as an alternative. Moreover, the
sensible heat exchange device 20 may be omitted.
[0107] Furthermore, in the above-described embodiments, the
desiccant portion 10 is rotatable. However, having the desiccant
portion 10 to be static, and a channel switching system may be used
as an alternative.
[0108] Moreover, the sensor portion 70 may be provided on the
upstream side of the desiccant portion 10.
DESCRIPTION OF THE REFERENCE SYMBOLS
[0109] 1 Air supply channel [0110] 2 Exhaust channel [0111] 10
desiccant portion [0112] 20 Sensible heat exchange device (sensible
heat exchange portion) [0113] 31 First cooling coil (first cooling
portion) [0114] 32 Centrifugal chiller [0115] 35 Header [0116] 36
Pre-cooling coil (pre-cooling portion) [0117] 41 Hot water heat
pump (heat pump) [0118] 42 Hot water circuit (higher temperature
heating medium circuit) [0119] 43 Heat source water circuit (lower
temperature heating medium circuit) [0120] 44 Second cooling coil
(second cooling portion) [0121] 45 Regeneration heating coil
(heating portion) [0122] 50 Heat supplying portion [0123] 60
Control portion [0124] A1 Outside air [0125] A2 Return air [0126]
S1, S2 Desiccant air-conditioning system
* * * * *