US20110083458A1

US20110083458A1 - Desiccant air conditioning system and method of operating the same

Info

Publication number: US20110083458A1
Application number: US12/902,383
Authority: US
Inventors: Yoshitaka Takakura; Makoto Tsubaki; Ryouta Dazai
Original assignee: Azbil Corp
Current assignee: Azbil Corp
Priority date: 2009-10-13
Filing date: 2010-10-12
Publication date: 2011-04-14
Also published as: JP2011085270A; KR20110040660A; CN102042645A; CN102042645B

Abstract

The present invention provides a dew point temperature sensor, detects a dew point temperature of supply air that is supplied to a dry room (i.e., the dew point temperature of process side dried air cooled by a cold water coil), and supplies such to a control apparatus as a supply air dew point temperature tdpv. When the supply air dew point temperature tdpv decreases, the control apparatus lowers the rotational speed of a regeneration side fan and a motor (i.e., a motor that drives a desiccant rotor). Furthermore, the dew point temperature of return air and the like may be detected instead of the dew point temperature of the supply air. In addition, the rotational speed of the regeneration side fan alone may be lowered. In addition, the present invention may be of a type that does not comprise the cold water coil or of a type wherein the return air does not return to the process side air.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2009-236208, filed. Oct. 13, 2009, which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a desiccant air conditioning system, wherein a desiccant rotor is provided and disposed such that it straddles a regeneration side air passageway and a process side air passageway and, while rotating, continuously adsorbs humidity from process side air and releases humidity to regeneration side air, and to a method of operating the same.

BACKGROUND OF THE INVENTION

Conventionally, to maintain low humidity in for example, a refrigerated warehouse or a battery plant, a desiccant air conditioning system (e.g., refer to Japanese Unexamined Patent Application Publication No. 2006-308229 and Japanese Unexamined Patent Application Publication No. 2001-241693), wherein a desiccant rotor is employed, is used for air conditioning.
The desiccant rotor is discoidally formed and has a structure such that air can pass through in the thickness directions. A solid adsorbent, whose main component is a porous inorganic compound, is provided to the surface of the desiccant rotor. An agent that adsorbs moisture and has a pore diameter of approximately 0.1-20.0 nm, for example, silica gel, zeolite, or a solid adsorbent such as a high polymer adsorbent, is used as the porous inorganic compound, in addition, a motor drives the desiccant rotor and, while rotating around a center axis, the desiccant rotor continuously adsorbs humidity from the process side air and releases humidity to the regeneration side air.
FIG. 9 schematically shows a conventional desiccant air conditioning system that uses a desiccant rotor. In this figure, 1 is a regeneration side fan that forms a regeneration side air current, 2 is a process side fan that forms a process side air current, 3 is a desiccant rotor provided and disposed such that it straddles a passageway L1 of the regeneration side air and a passageway L2 of the process side air, 4 is a cold water coil (i.e., a cooling apparatus) that cools dried air on the process side after its humidity has been adsorbed by the desiccant rotor 3, 5 is a hot water coil (i.e., a heating apparatus) that heats the air before its humidity is released by the desiccant rotor 3, 6 is a motor that rotates the desiccant rotor 3, 7 is a temperature sensor that measures the temperature of dried air SA (i.e., supply air) on the process side that has been cooled by the cold water coil 4, and 8 is a temperature sensor that measures the temperature of air SR (i.e., regeneration air) on the regeneration side that has been heated by the hot water coil 5; these elements constitute a desiccant air conditioner 100.
Cold water CW is supplied via a cold water valve 9 to the cold water coil 4 of the desiccant air conditioner 100, and hot water HW is supplied via a hot water valve 10 to the hot water coil 5. In addition, a controller 11 is provided to the cold water coil 4, and a controller 12 is provided to the hot water coil 5. The controller 11 controls the degree of opening of the cold water valve 9 such that a temperature tspv of the supply air SA, which the temperature sensor 7 measures, coincides with a set temperature tssp. The controller 12 controls the degree of opening of the hot water valve 10 such that a temperature trpv of the regeneration air SR, which the temperature sensor 8 measures, coincides with a set temperature trsp. 200 is a dry room (i.e., a space to be air conditioned), which is supplied with supply air SA from the desiccant air conditioner 100.

Process Side

In this desiccant air conditioning system, return air RA from the dry room 200 returns to the process side air, which is air before its humidity is adsorbed by the desiccant rotor 3. In the present example, the return air RA mixes with outside air OA to become the process side air, which is air before its humidity is adsorbed by the desiccant rotor 3. Furthermore, the amount of the return air RA from the dry room 200 is constant. In addition, the amount of the outside air OA mixed with the return air RA is controlled by a room pressure control apparatus (not shown) such that the room pressure in the dry room 200 is constant.
On the process side, when an air mixture of the return air RA and the outside air OA passes through the desiccant rotor 3, the solid adsorbent of the desiccant rotor 3 adsorbs (i.e., via humidity adsorption) the moisture contained in that air. Furthermore, the air mixture of the return air RA and the outside air OA after the humidity adsorption by the desiccant rotor 3, namely, the air mixture of the return air RA and the outside air OA that the desiccant rotor 3 has dehumidified, is sent to and cooled by the cold water coil 4 and then supplied to the dry room 200 as the supply air SA.

Regeneration Side

Moreover, on the regeneration side, the outside air OA is taken in as the regeneration side air and then sent to and heated by the hot water coil 5. Thereby, the temperature of the outside air OA rises and its relative humidity falls. In this case, the temperature of the outside air OA is high, exceeding 100° C. The high temperature outside air OA, whose relative humidity has fallen, is sent as the regeneration air SR to the desiccant rotor 3, whose solid adsorbent it heats.
Namely, the desiccant rotor 3 rotates and the solid adsorbent, which adsorbed moisture from the air mixture of the return air RA and the outside air OA on the process side, is heated when it meets the regeneration air SR. Thereby, the moisture is desorbed from the solid adsorbent and humidity is released to the regeneration air SR. The regeneration air SR, which absorbed moisture from the solid adsorbent, is exhausted as exhaust air EA.
Thus, in the conventional desiccant air conditioning system, the supply air SA (i.e., dry air) is continuously supplied from the desiccant air conditioner 100 to the dry room 200 by the action of the desiccant rotor 3, which continuously adsorbs humidity from the air mixture of the return air RA and the outside air OA (i.e., the process side air) and releases humidity to the regeneration air SR (i.e., the regeneration side air) while rotating at a constant rotational speed and fixing the rotational speeds (i.e., rated rotational speeds) of the regeneration side fan 1 and the process side fan 2.
Nevertheless, in the conventional desiccant air conditioning system discussed above, the amount of the air that flows to the regeneration side of the desiccant rotor 3 is constant and, to ensure that the moisture adsorbed during peak operation can be released, is set such that the amount of moisture adsorption on the process side of the desiccant rotor 3 during peak operation serves as a reference; consequently, the hot water coil 5, the cold water coil 4, and the like consume an extreme amount of energy and the operating cost is enormous, both of which are problems.
Namely, if the amount of moisture contained in the process side air (i.e., the air mixture of the return air RA and the outside air OA) is small, then the amount of moisture the solid adsorbent of the desiccant rotor 3 adsorbs is small. Accordingly, on the regeneration side, the amount of moisture desorbed from the solid adsorbent of the desiccant rotor 3 will likewise be small. Regardless, the amount of the regeneration side air (i.e., the regeneration air SR) supplied to the desiccant rotor 3 is fixed taking as a reference the amount of moisture adsorption on the process side during peak operation.
Consequently, the regeneration air SR is supplied to the desiccant rotor 3 more than is necessary and, to that extent, the hot water coil 5 wastes energy. In addition, the portion of the desiccant rotor 3 that is positioned on the regeneration side and that receives the supply of the regeneration air SR becomes hotter, and this heat is transferred to the process side by the rotation of the desiccant rotor 3. Consequently, the amount of heat transferred from the regeneration side to the process side of the desiccant rotor 3 increases, the temperature of the air mixture of the return air RA and the outside air OA that passes through the desiccant rotor 3 increases, the temperature of the air mixture increases, and thereby the amount of energy the cold water coil 4 consumes increases.
Furthermore, in FIG. 9, the desiccant air conditioner 100 is the type that comprises the cold water coil 4, but a type that does not comprise the cold water coil 4 also exists. Namely, a type of desiccant air conditioner (i.e., an outdoor air conditioner) that supplies air, which the desiccant rotor 3 has dehumidified, to the dry room 200 as the supply air SA without cooling that air also exists. In such a desiccant air conditioner (i.e., outdoor air conditioner), while the cold water coil 4 consumes no energy, the hot water coil 5 consumes a greater amount of energy, which results in a huge operating cost.
The present invention was conceived to solve such problems, and it is an object of the present invention to supply a desiccant air conditioning system that can achieve significant energy savings and a method of operating the same.

SUMMARY OF THE INVENTION

To achieve the abovementioned object, the present invention provides a desiccant air conditioning system that includes a regeneration side fan, which forms a regeneration side air current; a process side fan, which forms a process side air current; a desiccant rotor, which is provided and disposed such that it straddles the regeneration side air passageway and the process side air passageway, that, while rotating, continuously adsorbs humidity from the process side air and releases humidity to the regeneration side air; a heating apparatus, which heats the regeneration side air before its humidity is released by the desiccant rotor; and a space to be air conditioned, which receives the supply of the process side dried air whose humidity has been adsorbed by the desiccant rotor; having a moisture amount detecting means, which detects an amount of moisture at a prescribed position in a passageway wherethrough the process side dried air flows; and a controlling means that, based on the amount of moisture detected by the moisture amount detecting means, controls the flow rate of the regeneration side air.
In the present invention, the amount of moisture at the prescribed position in the passageway wherethrough the process side dried air flows is detected, and the flow rate of the regeneration side air is controlled based on the detected amount of moisture. For example, if the detected amount of moisture decreases, then the flow rate of the regeneration side air is reduced. In this case, reducing the flow rate of the regeneration side air raises the temperature of the regeneration air from the heating apparatus. Accordingly, if control is performed to maintain the regeneration air at a constant temperature, then the heating apparatus's amount of heating decreases and thereby the energy the heating apparatus consumes decreases. In addition, decreasing the flow rate of the regeneration side air decreases the amount of heat that is transferred from the regeneration side to the process side of the desiccant rotor, which prevents the temperature of the process side air that passes through the desiccant rotor from rising. Thereby, in an air conditioner of a type that comprises a cooling apparatus, the energy the cooling apparatus consumes is also reduced.
According to the present invention, because a flow rate of regeneration side air is controlled based on an amount of moisture detected at a prescribed position in a passageway wherethrough process side dried air flows, if the detected amount of moisture decreases, then the flow rate of the regeneration side air is reduced, which makes it possible to reduce the energy a heating apparatus consumes (and, in the case of a type that comprises a cooling apparatus, also to reduce the energy the cooling apparatus consumes) and thereby to achieve a significant energy savings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows an example of a desiccant air conditioning system according to the present invention.

FIG. 2 is a flow chart for explaining an energy saving function provided by a control apparatus in the desiccant air conditioning system of the above example.

FIG. 3 schematically shows another example of the desiccant air conditioning system according to the present invention.

FIG. 4 is a flow chart for explaining the energy saving function provided by the control apparatus in the desiccant air conditioning system of the other example.

FIG. 5 illustrates a temperature distribution before the flow rate of regeneration side air in a desiccant rotor decreases.

FIG. 6 shows an example of detecting the dew point temperature of return air (i.e., the return air dew point temperature) from a dry room.

FIG. 7 shows an example of detecting the dew point temperature of exhaust air (i.e., the exhaust air dew point temperature) from the dry room.

FIG. 8 shows an example wherein process side air, whose humidity has been adsorbed by the desiccant rotor, returns to the desiccant rotor as the regeneration side air.

FIG. 9 schematically shows a conventional desiccant air conditioning system.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The details of an embodiment of the present invention are explained below, referencing the drawings.
FIG. 1 is a diagram that schematically shows an example of a desiccant air conditioning system according to the present invention. Symbols in FIG. 1 that are identical to those in FIG. 9 indicate constituent elements that are identical or equivalent to those explained referencing FIG. 9, and explanations thereof are therefore omitted.
In this example, a regeneration side fan 1 is accessorized with an inverter INV1 to enable the rotational speed of the regeneration side fan 1 to be adjusted. In addition, a dew point temperature sensor 13 detects the dew point temperature of supply air SA (i.e., the dew point temperature of dried air on the process side that has been cooled by a cold water coil 4) supplied to a dry room 200, and a dew point temperature tdpv of the supply air SA (i.e., a supply air dew point temperature) detected by the dew point temperature sensor 13 is supplied to a control apparatus 14 (14-1).
The control apparatus 14-1 is implemented using hardware, which includes a processor, a storage apparatus, and the like, and a program, which cooperates with the hardware to implement various functions; furthermore, the control apparatus 14-1 has a function unique to the present embodiment, namely, a control function (also called an energy saving function) that controls the rotational speed of the regeneration side fan 1. The text below explains the energy saving function provided by the control apparatus 14-1, referencing the flow chart depicted in FIG. 2.
The control apparatus 14-1 captures, with a fixed periodicity, the supply air dew point temperature tdpv front the dew point temperature sensor 13 (i.e., in a step S101) and compares the supply air dew point temperature tdpv with a preset set value tdsp of the supply air dew point temperature in a step S102). Furthermore, in this case, the supply air dew point temperature tdpv indicates the amount of moisture the supply air SA contains; furthermore, a high supply air dew point temperature tdpv indicates that the supply air SA contains a large amount of moisture, and a low supply air dew point temperature tdpv indicates that the supply air SA contains a small amount of moisture.
If the supply air dew point temperature tdpv is lower than the set value tdsp of the supply air dew point temperature (i.e., if the decision box tdpv<tdsp leads to YES in the step S102), then the control apparatus 14-1 lowers the rotational speed of the regeneration side fan 1 (i.e., in a step S103). In this case, the control apparatus 14-1 calculates a difference Δtd between the supply air dew point temperature tdpv and the set value tdsp of the supply air dew point temperature (i.e., Δtd=|tdpv−tdsp|), outputs a control output S1 based on the difference Δtd to the inverter INV1, and lowers the rotational speed of the regeneration side fan 1 by an amount that corresponds to the difference 40 between the supply air dew point temperature tdpv and the set value tdsp of the supply air dew point temperature.
Thereby, the amount of regeneration air SR supplied to a desiccant rotor 3 decreases, the amount of the regeneration side moisture the desiccant rotor 3 adsorbs decreases, the amount of process side moisture adsorbed decreases, and thereby the supply air dew point temperature tdpv increases to match the set value tdsp of the supply air dew point temperature.
In the above control process, if the rotational speed of the regeneration side fan 1 decreases, then the regeneration side air flow rate decreases and the temperature of the regeneration air SR from a hot water coil 5 increases. In this case, a controller 12, which is provided for the hot water coil 5, controls the degree of opening of a hot water valve 10 such that a temperature trpv of the regeneration air SR is maintained at a set temperature trsp. Thereby, the amount of hot water HW supplied to the hot water coil 5 (i.e., an amount of heating) decreases and the energy the hot water coil 5 consumes is reduced.
In addition, the decreased flow rate of the regeneration side air reduces the amount of heat transferred from the regeneration side to the process side of the desiccant rotor 3. Consequently, the temperature of the process side air that passes through the desiccant rotor 3 is prevented from increasing. In this case, a controller 11, which is provided for the cold water coil 4, controls the degree of opening of a cold water valve 9 such that a temperature tspv of the supply air SA is maintained at a set temperature tssp. Thereby, the amount of cold water CW supplied to the cold water coil 4 (i.e., an amount of cooling) decreases and the energy the cold water coil 4 consumes is likewise reduced.
In addition, lowering the rotational speed of the regeneration side fan 1 likewise reduces the energy needed to drive the regeneration side fan 1.
Thus, in the present embodiment, when the supply air dew point temperature tdpv is lower than the set value tdsp of the supply air dew point temperature, the energy the hot water coil 5, the cold water coil 4, and the like consume is reduced; in addition, the energy needed to drive the regeneration side fan 1 is also reduced; thereby, a significant energy savings is realized on both the process side and the regeneration side. In particular, the reduction in the amount of energy the hot water coil 5, the cold water coil 4, and the like consume is extremely large, which makes it possible to achieve a tremendous energy savings.
If the supply air dew point temperature tdpv is higher than the set value tdsp of the supply air dew point temperature (i.e., if the decision box tdpv>tdsp leads to YES in the step S104), then the control apparatus 14-1 raises the rotational speed of the regeneration side fan 1 (i.e., in a step S105). In this case, the control apparatus 14-1 calculates a difference Δtd between the supply air dew point temperature tdpv and the set value tdsp of the supply air dew point temperature (i.e. Δtd=|tdpv−tdsp|), outputs a control output S1 based on the difference Δtd to the inverter INV1, and raises the rotational speed of the regeneration side fan 1 by an amount that corresponds to the difference Δtd between the supply air dew point temperature tdpv and the set value tdsp of the supply air dew point temperature.
Thereby, the amount of regeneration air SR supplied to the desiccant rotor 3 increases, the amount of the regeneration side moisture the desiccant rotor 3 adsorbs increases, the amount of process side moisture adsorbed increases, and thereby the supply air dew point temperature tdpv decreases to match the set value tdsp of the supply air dew point temperature.
FIG. 3 is a diagram that schematically shows another example of the desiccant air conditioning system according to the present invention.
In this example, the regeneration side fan 1 is accessorized with the inverter INV1 to enable the rotational speed of the regeneration side fan 1 to be adjusted. In addition, the motor 6, which drives the desiccant rotor 3, is accessorized with an inverter INV2 to enable the rotational speed of the motor 6 to be adjusted. In addition, the dew point temperature sensor 13 detects the dew point temperature of the supply air SA (i.e., the dew point temperature of dried air on the process side that has been cooled by the cold water coil 4) supplied to the dry room 200, and the dew point temperature tdpv of the supply air SA (i.e., the supply air dew point temperature) detected by the dew point temperature sensor 13 is supplied to a control apparatus 14 (14-2).
The control apparatus 14-2 is implemented using hardware, which comprises a processor, a storage apparatus, and the like, and a program, which cooperates with the hardware to implement various functions; furthermore, the control apparatus 14-2 has a function unique to the present embodiment, namely, a control function (also called an energy saving function) that controls the rotational speed of the regeneration side fan 1 and the rotational speed of the motor 6. The text below explains the energy saving function provided by the control apparatus 14-2, referencing the flow chart depicted in FIG. 4.
The control apparatus 14-2 captures, with a fixed periodicity, the supply air dew point temperature tdpv from the dew point temperature sensor 13 (i.e., in a step S201) and compares the supply air dew point temperature tdpv with the preset set value tdsp of the supply air dew point temperature (i.e., in a step S202).
If the supply air dew point temperature tdpv is lower than the set value tdsp of the supply air dew point temperature (i.e., if the decision box tdpv<asp leads to YES in the step S202), then the control apparatus 14-2 lowers the rotational speed of the regeneration side fan 1 (i.e., in a step S203) and the rotational speed of the motor 6. In this case, the control apparatus 14-2 calculates the difference Δtd between the supply air dew point temperature tdpv and the set value tdsp of the supply air dew point temperature (i.e., Δtd=|tdpv−tdsp|), outputs the control output S1 and a control output S2 based on the difference Δtd to the inverters INV1, INV2, respectively, and lowers the rotational speed of the regeneration side fan 1 and the rotational speed of the motor 6 by an amount that corresponds to the difference Δtd between the supply air dew point temperature tdpv and the set value tdsp of the supply air dew point temperature.
In the above control process, if the rotational speed of the regeneration side fan 1 decreases, then the regeneration side air flow rate decreases and the temperature of the regeneration air SR from the hot water coil 5 increases. In this case, the controller 12, which is provided for the hot water coil 5, controls the deuce of opening of the hot water valve 10 such that the temperature trpv of the regeneration air SR is maintained at a set temperature trsp. Thereby; the amount of hot water HW supplied to the hot water coil 5 (i.e., the amount of heating) decreases and the energy the hot water coil 5 consumes is reduced.
In addition, the decreased flow rate of the regeneration side air reduces the amount of heat transferred from the regeneration side to the process side of the desiccant rotor 3. Consequently, the temperature of the process side air that passes through the desiccant rotor 3 is prevented from increasing. In this case, the controller 11, which is provided for the cold water coil 4, controls the degree of opening of the cold water valve 9 such that the temperature tspv of the supply air SA is maintained at the set temperature tssp. Thereby, the amount of cold water CW supplied to the cold water coil 4 (i.e., an amount of cooling) decreases and the energy the cold water coil 4 consumes is likewise reduced.
Furthermore, if the flow rate of the regeneration side air becomes low, then the temperature distribution of the desiccant rotor 3 will change. In other words, the temperature distribution of the desiccant rotor 3 does change. In the first embodiment, it is assumed that the change in the temperature distribution of the desiccant rotor 3 that accompanies a change in the flow rate of the regeneration side air is small, and therefore only the flow rate of the regeneration side air is controlled. In contrast, in this example, it is assumed that the change in the temperature distribution of the desiccant rotor 3 is large, and therefore in addition to the control of the flow rate of the regeneration side air, the rotational speed of the desiccant rotor 3 is also controlled.
FIG. 5 illustrates the temperature distribution of the desiccant rotor 3 before the flow rate of the regeneration side air decreases. If the rotational speed of the motor 6 (i.e., the rotational speed of the desiccant rotor 3) were kept constant and not reduced, then reducing the flow rate of the regeneration side air would change the direction in which the temperature decreases within the temperature distribution. Accordingly, in the present example, the rotational speed of the motor 6 is also reduced, and therefore the temperature distribution does not change.
Thereby, in the state wherein the temperature distribution in the desiccant rotor 3 is maintained, the amount of regeneration air SR supplied to the desiccant rotor 3 decreases, the amount of the regeneration side moisture the desiccant rotor 3 adsorbs decreases, the amount of process side moisture adsorbed decreases, and thereby the supply air dew point temperature tdpv increases to match the set value tdsp of the supply air dew point temperature.
Thus, in the present example, when the supply air dew point temperature tdpv is lower than the set value tdsp of the supply air dew point temperature, the energy the hot water coil 5, the cold water coil 4, and the like consume is reduced; in addition, the energy needed to drive the desiccant rotor 3 and the energy needed to drive the regeneration side fan 1 are also reduced; thereby, a significant energy savings is realized on both the process side and the regeneration side.
If the supply air dew point temperature tdpv is higher than the set value tdsp of the supply air dew point temperature (i.e., if the decision box tdpv>tdsp leads to YES in the step S204), then the control apparatus 14-2 raises the rotational speed of the regeneration side fan 1 and the rotational speed of the motor 6 (i.e., in a step S205). In this case, the control apparatus 14-2 calculates the difference Δtd between the supply air dew point temperature tdpv and the set value tdsp of the supply air dew point temperature (i.e., Δtd=|tdpv−tdsp|), outputs the control outputs S1, S2 based on the difference Δtd to the inverters ENV1, INV2, respectively, and raises the rotational speed of the regeneration side fan 1 and the rotational speed of the motor 6 by an amount that corresponds to the difference Δtd between the supply air dew point temperature tdpv and the set value tdsp of the supply air dew point temperature.
Thereby, in the state wherein the temperature distribution in the desiccant rotor 3 is maintained, the amount of regeneration air SR supplied to the desiccant rotor 3 increases, the amount of the regeneration side moisture the desiccant rotor 3 adsorbs increases, the amount of process side moisture adsorbed increases, and thereby the supply air dew point temperature tdpv decreases to match the set value tdsp of the supply air dew point temperature.
Furthermore, in the examples discussed above, the dew point temperature sensor 13 detects the dew point temperature of the supply air SA (i.e., the supply air dew point temperature) supplied to the dry room 200; however, as shown in a modified example of the second embodiment in FIG. 6, the dew point temperature sensor 13 may detect the dew point temperature of return air RA (i.e., a return air dew point temperature) from the dry room 200, and the rotational speeds of the regeneration side fan 1 and the motor 6 may be controlled in accordance with the difference Δtd between the return air dew point temperature tdpv detected by the dew point temperature sensor 13 and the preset set value tdsp of the return air dew point temperature.
In addition, as shown in a modified example of the above example in FIG. 7, the dew point temperature sensor 13 may detect the dew point temperature of exhaust air EXA (i.e., an exhaust air dew point temperature) from the dry room 200, and the rotational speeds of the regeneration side fan 1 and the motor 6 may be controlled in accordance with the difference Δtd between the exhaust air dew point temperature tdpv detected by the dew point temperature sensor 13 and the preset set value tdsp of the exhaust air dew point temperature.
In addition, the point at which the dew point temperature is detected does not necessarily have to be in the supply air SA, the return air RA, or the exhaust air EXA, and may be any point in the passageway wherethrough the dried air (i.e., dry air) on the process side flows after the desiccant rotor 3 adsorbed the moisture. In addition, the object of detection does not have to be the dew point temperature, and may be humidity instead. In this case, either the relative humidity or the absolute humidity may be detected.
In addition, for example, the dew point temperature of the return air RA may be detected, and the rotational speeds of the regeneration side fan 1, the motor 6, and the like may be controlled (i.e., using cascade control) such that, at that detected return air RA dew point temperature, the dew point temperature of the supply air SA reaches a set value.
In addition, as shown in a modified example of the second embodiment in FIG. 8, the process side air whose humidity was adsorbed by the desiccant rotor 3 may serve as the regeneration side air and return to the desiccant rotor 3. In this case, various systems are conceivable: for example, a system, as shown by the solid lines in FIG. 8, wherein the process side air whose humidity was adsorbed by the desiccant rotor 3 passes through the hot water coil 5 and is supplied to the desiccant rotor 3 and a system, as indicated by the dotted lines in FIG. 8, wherein the process side air whose humidity was adsorbed by the desiccant rotor 3 is supplied to the regeneration side of the desiccant rotor 3 and heated thereby, the air heated by the regeneration side of the desiccant rotor 3 passes through the hot water coil 5, and this air is once again supplied to the desiccant rotor 3.
In addition, in the examples discussed above, the flow rate of the regeneration side air does not necessarily have to be controlled based on the rotational speed of the regeneration side fan 1; for example, a damper may be provided in the passageway of the regeneration side air, and the flow rate of the regeneration side air may be controlled by adjusting the damper's degree of opening. In addition, the regeneration side fan 1 does not necessarily have to be provided downstream of the desiccant rotor 3 (i.e., on the exit side of the regeneration side air) and may be provided upstream of the desiccant rotor 3 (i.e., on the entrance side of the regeneration side air).
In addition, in the examples discussed above, the return air RA from the dry room 200 returns to the air on the process side before its humidity is adsorbed by the desiccant rotor 3; however, the return air RA from the dry room 200 may be eliminated and outside air OA alone may be supplied as the process side air to the desiccant rotor 3.
In addition, in the embodiments discussed above, a heating apparatus that heats the regeneration side air serves as the hot water coil 5, and a cooling apparatus that cools the dried air on the process side serves as the cold water coil 4, but the heating apparatus and the cooling apparatus are not limited to the hot water coil 5 and the cold water coil 4, respectively.
In addition, in the embodiments discussed above, the desiccant air conditioner 100 is the type that comprises the cold water coil 4, but it may be a type that does not comprise the cold water coil 4. Namely, the desiccant air conditioner 100 (i.e., an outdoor air conditioner) may be a type wherein the desiccant rotor 3 supplies dehumidified air as the supply air SA to the dry room 200 without cooling that air.
In the desiccant air conditioner 100 of this type (i.e., an outdoor air conditioner), while no energy consumption occurs at the cold water coil 4, the hot water coil 5 does consume energy. In this case, making the flow rate of the regeneration side air low reduces the energy consumption at the hot water coil 5, thereby achieving significant energy savings.
The desiccant air conditioning system and the method of operating the same according to the present invention can be adapted as air conditioning for maintaining a low humidity in various contexts, such as in a lithium battery plant, a foodstuffs plant, or a distribution warehouse.

Claims

1. A desiccant air conditioning system that comprises: a regeneration side fan, which forms a regeneration side air current; a process side fan, which forms a process side air current; a desiccant rotor, which is provided, and disposed such that it straddles the regeneration side air passageway and the process side air passageway, that, while rotating, continuously adsorbs humidity from the process side air and releases humidity to the regeneration side air; a heating apparatus, which heats the regeneration side air before its humidity is released by the desiccant rotor; and a space to be air conditioned, which receives the supply of the process side dried air whose humidity has been adsorbed by the desiccant rotor; comprising:

a moisture amount detector detecting an amount of moisture at a prescribed position in a passageway wherethrough the process side dried air flows; and

a controller that, based on the amount of moisture detected by the moisture amount detector, controls the flow rate of the regeneration side air.

2. A desiccant air conditioning system according to claim 1, wherein

the controller controls, based on the amount of moisture detected by the moisture amount detector, the flow rate of the regeneration side air and the rotational speed of the desiccant rotor.

3. A desiccant air conditioning system according to claim 1, wherein

the moisture amount detector detects the amount of moisture contained in the supply air that is supplied to the space to be air conditioned.

4. A desiccant air conditioning system according to claim 1, wherein

the moisture amount detector detects the amount of moisture contained in the air that exits the space to be air conditioned.

5. A desiccant air conditioning system according to claim 1, wherein the moisture amount detector detects the amount of moisture as a proxy for a dew point temperature.

6. A desiccant air conditioning system according to claim 1, wherein the moisture amount detector detects the amount of moisture as a proxy for a level of humidity.

7. A desiccant air conditioning system operating method adapted to a desiccant air conditioning system that comprises: a regeneration side fan, which forms a regeneration side air current; a process side fan, which forms a process side air current; a desiccant rotor, which is provided and disposed such that it straddles the regeneration side air passageway and the process side air passageway, that, while rotating, continuously adsorbs humidity from the process side air and releases humidity to the regeneration side air; a heating apparatus, which heats the regeneration side air before its humidity is released by the desiccant rotor; and a space to be air conditioned, which receives the supply of the process side dried air whose humidity has been adsorbed by the desiccant rotor; comprising the steps of:

a moisture amount detecting step detecting an amount of moisture at a prescribed position in a passageway wherethrough the process side dried air flows; and

a controlling step controlling the flow rate of the regeneration side air based on the amount of moisture detected by the moisture amount detecting step.