Abstrict A method and system for climate control uses a desiccant in an
automobile. The desiccant removes humidity or moisture from air
passing through the ventilation system. The desiccant is recharged
or dried by application of a vacuum. The lower pressure generated
by the vacuum reduces the temperature at which water evaporates
or boils off of the desiccant material.
Claims What is claimed is:
1. A system for climate control using desiccant in an automobile,
the system comprising: a desiccant exposed to air within an automobile;
a vacuum source operative to generate a low pressure area adjacent
at least a portion of the desiccant; a chamber connected with the
vacuum source, the portion of the desiccant including opposite sides
of the desiccant both being in the chamber and both subjected to
the low pressure area at a same time; and an actuator connected
with the desiccant, the actuator operable to move the desiccant
relative to the air and the chamber.
2. The system of claim 1 further comprising an air duct operatively
connected with an automobile passenger compartment wherein the desiccant
is exposed to air within the air duct.
3. The system of claim 1 wherein the vacuum source comprises a
vacuum pump associated with an engine of the automobile.
4. The system of claim 1 wherein the vacuum source comprises suction
responsive to flowing liquid.
5. The system of claim 4 wherein the flowing liquid comprises engine
coolant.
6. The system of claim 1 wherein the desiccant comprises a cartridge
of silica gel.
7. The system of claim 1 further comprising an activated carbon
filter adjacent the desiccant.
8. The system of claim 1 wherein the desiccant comprises a segmented
desiccant cartridge.
9. The system of claim 8 wherein a first segment of the segmented
desiccant cartridge is exposed to an airstream and a second segment
of the segmented desiccant cartridge is exposed to the vacuum source.
10. The system of claim 9 an wherein the actuator is operable to
reverse the exposure of the first and second segments.
11. A method for climate control with a desiccant in an automobile,
the method comprising: (a) exposing a desiccant to air within a
passenger compartment of an automobile; (b) generating a low pressure
area adjacent at least a portion of the desiccant, the low pressure
sufficient to lower a boiling or evaporation temperature of water
from the desiccant, the low pressure relative to the air; (c) moving
the desiccant relative to the air and the low pressure area.
12. The method of claim 11 wherein (a) comprises exposing the desiccant
within an air duct.
13. The method of claim 11 wherein (b) comprises generating the
low pressure area with a vacuum pump.
14. The method of claim 11 wherein (b) comprises generating the
low pressure area with fluid flow.
15. The method of claim 14 wherein (b) comprises generating the
low pressure area with engine coolant.
16. The method of claim 11 wherein (a) comprises exposing silica
gel.
17. The method of claim 11 further comprising: (d) removing humidity
from the air in response to (a).
18. The method of claim 11 further comprising: (d) filtering the
air with an activated carbon filter.
19. The method of claim 11 wherein the desiccant comprises a segmented
desiccant cartridge and (a) comprises exposing a first segment of
the segmented desiccant cartridge; further comprising (d) exposing
a second segment of the segmented desiccant cartridge to the low
pressure area.
20. The method of claim 11 wherein (c) comprises switchably positioning
a first portion of the desiccant to be exposed pursuant to (a) and
a second portion to be exposed to the low pressure area.
21. A system for climate control using desiccant in an automobile,
the system comprising: an air duct; a vacuum chamber; a desiccant
positionable within the air duct and the vacuum chamber; an actuator
operatively connected with the desiccant, the position of the desiccant
relative to the air duct and the vacuum chamber responsive to the
actuator; and a controller connected with the actuator; wherein
the vacuum chamber is operable to remove moisture from the desiccant.
22. A system for climate control using desiccant in an automobile,
the system comprising: a desiccant exposed to air within an automobile;
a chamber operative to contain a low pressure area adjacent at least
a portion of the desiccant; and a hose connected with the chamber,
the hose operable to generate the low pressure in response to flowing
liquid.
Description BACKGROUND
This invention relates to dehumidification in an enclosed area.
In particular, a method and system for climate control using a desiccant
in an automobile is provided.
Humidity in automobiles condenses on windows, impairing a vehicle
operator's vision. For lower temperatures with high humidity, the
typical ventilation system in an automobile may be incapable of
effectively, efficiently or quickly removing the condensation. For
example, air is recirculated from within a passenger compartment.
Recirculating the air delays or prevents removal of the condensation
from the window.
Desiccant systems have been developed for use in busses. Desiccants
absorb a limited amount of moisture. Once the limited amount of
moisture has been absorbed, the desiccant is dried or recharged
by application of heat. The desiccant is exposed to exhaust gases
from the engine. However, it is undesirable to route exhaust gases
adjacent to the air duct or ventilation system of the bus. The proximity
and connection between the exhaust gases and the air ducts for ventilation
may allow leakage of exhaust into the passenger compartment. Furthermore,
the exhaust gases can foul or otherwise deteriorate the desiccant
material.
BRIEF SUMMARY
The present invention is defined by the following claims, and nothing
in this section should be taken as a limitation on those claims.
By way of introduction, the preferred embodiment described below
includes a method and system for climate control using a desiccant
in an automobile.
A desiccant removes humidity or moisture from air passing through
the ventilation system. The desiccant is recharged or dried by application
of a vacuum. The lower pressure generated by the vacuum reduces
the temperature at which water evaporates or boils off of the desiccant
material.
In one aspect, a method and system for climate control of a desiccant
in an automobile are provided. A desiccant is exposed to air within
an automobile. A vacuum source is operative to generate a low pressure
area adjacent to at least a portion of the desiccant.
In another aspect, a system for climate control using a desiccant
in an automobile is provided. The system includes an air duct and
a vacuum chamber. A desiccant is positionable within the air duct
and the vacuum chamber. An actuator operatively connects with the
desiccant. The position of the desiccant relative to the air duct
in the vacuum chamber is responsive to the actuator. A controller
connects with the actuator.
Further aspects and advantages of the invention are discussed below
in conjunction with the preferred embodiments.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a diagram of one embodiment of a system for climate control
using desiccant.
FIG. 2 is a diagram of another embodiment of a system for climate
control using a desiccant.
FIG. 3 is a flow chart diagram representing one embodiment of the
operation of the system of FIG. 2.
FIG. 4 is a perspective view of a system for climate control using
a desiccant of yet another embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The embodiments discussed below use a vacuum or low pressure to
recharge a desiccant. The humidity or moisture absorbed by the desiccant
is removed by evaporation due to the low pressure. The desiccant
is repetitively used to remove humidity or moisture from the air
in the passenger compartment of an automobile. When air is recirculated
within the passenger compartment through the ventilation system
in high humidity and lower temperature environments, the desiccant
removes humidity. The drier air within the passenger compartment
does not allow formation of condensation on windows. The system
also allows use of recirculating air for faster warming up of the
vehicle during particularly low temperature environments. The system
may decrease the load on an air conditioning system in a higher
temperature environments.
FIG. 1 shows one embodiment of a system for climate control using
a desiccant. A desiccant 10 is provided in or adjacent to an air
duct 12 and a vacuum chamber 14. The air duct 12 comprises a metallic,
plastic or other tube or chamber of air. The air duct 12 is shaped
as a tube, cylinder, rectangular or square shaped tube or any other
geometric body for the transport of air. The air duct 12 may be
of any of various sizes. The air duct 12 connects with a passenger
compartment of an automobile in one embodiment. For example, the
air duct 12 comprises a return air duct of an air handling case
in an automobile. As yet another example, the air duct 12 comprises
an air intake inlet or vent of the return air duct behind or below
a dashboard of an automobile. In alternative embodiments, the air
duct 12 connects with other chambers, compartments or bodies of
air where reduced humidity is desired.
The desiccant 10 comprises a silica-based desiccant cartridge.
In alternative embodiments, the desiccant comprises a zeolite, clay
base or salt base desiccant. One to two pounds or other amounts
of silica desiccant material are placed within a plastic or metallic
cartridge allowing exposure of the desiccant 10 to air. The desiccant
10 is shaped in any of various shapes, such as a rectangular or
circular volume. The desiccant 10 is sized such that it fits within
or adjacent to the air duct 12 impeding none, a portion or the
entire air duct 12.
Additional material may be provided with the desiccant 10. For
example, activated carbon is incorporated within the desiccant material
10 or adjacent to the desiccant 10. Activated carbon reduces odors
within the air traveling through or near the desiccant 10. Alternatively
or additionally, a biocide, such as antifungal or antimold material,
is included with or adjacent to the desiccant material 10. Other
air purifying or conditioning materials may be used.
The vacuum chamber 14 comprises a vacuum source. The vacuum chamber
14 comprises a volume of various shapes and sizes, such as a generally
rectangular volume sized to include at least a portion of the desiccant
10. The vacuum chamber 14 may be larger than the volume needed to
house the desiccant material 10. The vacuum chamber 14 is formed
from plastic, metal or other material able to withstand a lower
pressure without collapse.
The vacuum chamber 14 has a low pressure. One or more of various
mechanisms may be used for generating the low pressure. For example,
the engine vacuum generated by an engine of an automobile is used
to create the low pressure within the vacuum chamber 14. As another
example, the Bernoulli affect is used to generate a vacuum within
the vacuum chamber 14. The flow of fluid within the automobile is
used to generate a suction, resulting in a vacuum. In one embodiment,
a hose connects the vacuum chamber 14 to an engine coolant hose.
The flow of engine coolant creates a suction within the vacuum chamber
14.
Water within the desiccant 10 in or adjacent to the vacuum chamber
14 is boiled or evaporated from the desiccant 10. The recharged
desiccant 10 is exposed to air in the passenger compartment, allowing
the recirculation of air within an automobile without excessive
fogging on windows and reducing the load on an air conditioning
system by removing latent heat from the air. The passive desiccant
10 reduces the power consumption of a climate control system within
an interior of an automobile in high humidity environments.
As shown, the desiccant 10 is within both the vacuum chamber 14
and the air duct 12. In one embodiment, the desiccant 10 is moveable
between or within each location. The desiccant 10 may be positioned
adjacent to one or both the air duct 12 and the vacuum chamber 12.
The desiccant 10 may be fixedly mounted in alternative embodiments.
FIG. 2 shows one embodiment of a system for climate control using
a desiccant in an automobile. The system includes a desiccant cartridge
20 first and second vacuum chambers 22 24 an air duct 26 a vacuum
tube 28 a vacuum source 30 an actuator 32 a controller 34 a
temperature sensor 36 and a humidity sensor 38. In response to control
signals from the controller 34 the actuator 32 acts to move portions
of the desiccant cartridge 20 into the air duct 26 and other portions
into one of the vacuum chambers 22 24. Continuous or substantially
continuous removal of humidity from air within the air duct 26 is
provided. The air duct 26 desiccant cartridge 20 and the vacuum
chambers 22 24 comprise the same or similar materials, shapes,
and sizes discussed above with respect to FIG. 1.
The desiccant cartridge 20 is segmented. A wall or barrier 40 separates
the desiccant cartridge 20 into at least two portions. The barrier
40 of one embodiment separates the desiccant cartridge 20 in half.
The barrier 40 is positioned such that a seal or partial seal is
provided to separate a portion of a desiccant cartridge 20 within
a vacuum chamber 22 24 from the portion of the desiccant cartridge
20 within the air duct 26. In the dual vacuum chamber embodiment
shown in FIG. 2 the ends of the desiccant cartridge 20 are also
shaped so as to provide a seal or partial seal between the vacuum
chambers 22 24 and the air duct 26. The desiccant cartridge 20
comprises a metal, plastic or other material in a web (i.e., screen)
or partial web-partial enclosure for exposing desiccant to air.
The desiccant cartridge 20 is mounted within slots or apertures
within the vacuum chambers 22 and 24. In one embodiment, rails or
other guiding mechanisms are additionally provided to guide the
desiccant cartridge 20 as it is positioned within the vacuum chambers
22 24 and the air duct 26. Rollers may also be provided for positioning
the desiccant cartridge 20.
Two vacuum chambers 22 24 are provided so that while one portion
of the desiccant cartridge 20 is within the air duct 26 the other
portion is exposed to the low pressure within one of the vacuum
chambers 22 24. When the desiccant cartridge 20 is repositioned,
the recharged portion of the desiccant cartridge 20 is exposed within
the air duct 26 and the portion of the desiccant cartridge 20 storing
more water is positioned in the associated vacuum chamber 22 24.
For example, a left or first half of a desiccant cartridge 20 is
positionable within a first vacuum chamber 22 and the air duct 26.
A right or second half of the desiccant cartridge 20 is positionable
within the air duct 26 and a second vacuum chamber 24. The portion
of the desiccant cartridge 20 exposed within the air duct 26 is
switched from one portion to the other of the desiccant cartridge
20. In alternative embodiments, a wheel structure is used for the
desiccant cartridge 20 and a single vacuum chamber 22 24 are provided.
The desiccant cartridge 20 is recharged by rotating the portion
of the desiccant cartridge 20 exposed within the air duct 26 into
the vacuum chamber 22. In other alternative embodiments, different
structures and different numbers of associated vacuum chambers may
be provided.
The vacuum source 30 is connected through the vacuum hose 28 to
the vacuum chambers 22 and 24. The same or different sources of
vacuum 30 may be used for each of the vacuum chambers 22 24. In
one embodiment, the vacuum source 30 comprises a fluid pump, such
as provided in a coolant system. A portion of the vacuum hose 28
comprises a hose for carrying engine coolant. An additional hose
is connected to the coolant hose for generating a suction with the
Bernoulli effect for the vacuum chambers 22 and 24. For example,
a T connection is used. In an alternative embodiment, the vacuum
source 30 comprises an engine vacuum or an auxiliary belt or electric
powered vacuum pump. For example, an auxiliary electrically powered
vacuum pump is provided in the engine compartment of the automobile.
The vacuum hose 28 communicates a suction or low pressure to the
vacuum chambers 22 24. In alternative embodiments, the vacuum source
30 connects directly to or is within the vacuum chambers 22 24.
The vacuum hose 28 comprises a rubber, plastic, fiber, metal, combinations
thereof or other material for transmitting liquid or gas, such as
air, to generate suction.
Where the Bernoulli effect is used, a degasser or other device
for removing air sucked into the flowing fluid to create the low
pressure is preferably provided. For example, coolant systems within
automobiles typically have a degasser.
The actuator 32 comprises an electric motor with a push rod assembly.
The actuator 32 is electrically activated to move the rod and connected
desiccant cartridge 20. Alternatively, an actuator with an associated
gear, pulley or belt system is used for repositioning or switching
the desiccant cartridge 20. The actuator 32 is positioned within
or adjacent to a vacuum chamber 24 the air duct 26 or another location.
The actuator 32 is positioned such that the desiccant cartridge
20 switchably recharges and exposes recharged desiccant within the
air duct 26. The actuator 32 may alternatively directly connect
with the cartridge 20. In alternative embodiments, hydraulic, vacuum
operated, or non-electric actuator devices are used for positioning
the desiccant cartridge 20.
A controller 34 controls operation of the actuator 32. The controller
34 comprises an application specific integrated circuit, a digital
signal processor, an analog circuit, a general processor, combinations
thereof or other device for receiving inputs and outputting control
signals to the actuator 32. In one embodiment, the controller 34
comprises a multifunction processor used for other control within
the automobile.
The controller 34 receives inputs from one or move devices. In
one embodiment, the controller 34 receives inputs from the temperature
sensor 36 the humidity sensor 38 and a recirculation control button
42. Different, additional, or fewer inputs may be provided. The
temperature sensor 36 the humidity sensor 38 and the recirculation
control button 42 comprise any one or more of various sensors or
buttons used in automobiles for climate control or other purposes
for the operation of the automobile. For example, the temperature
and humidity sensors 32 38 used for automatic climate control are
also used as input to the controller 34 for operation of the actuator
32. The recirculation button 42 comprises a button, slide or other
input device for the operator of the automobile to select recirculation
of air within the ventilation system.
The controller 34 responds to the input from one or more devices,
such as the temperature sensor 36 the humidity sensor 38 and the
recirculation control button 42. In response to the inputs, the
controller 34 causes the actuator 32 to reposition the desiccant
cartridge 20. In one embodiment where the climate control system
is set to recirculate air within the passenger compartment, the
controller monitors the temperature and humidity from the temperature
sensor 36 and humidity sensor 38. Where a threshold level of humidity
and a threshold lower temperature is detected, the controller 34
causes the actuator to position a recharged portion of the desiccant
cartridge 20 within or adjacent to the air duct 26. The controller
34 then periodically repositions the desiccant cartridge 20 or,
after a predetermined time, monitors the environment as discussed
above until another reposition is triggered.
Repositioning of the desiccant cartridge 20 after a time or periodically
continues until the climate control system is removed from a recirculation
mode, the temperature exceeds a threshold, the humidity 38 becomes
sufficiently low, an air conditioning compressor turns on, another
event occurs or combinations thereof. Depending on the desiccant,
an amount of wator vapor that is about 20-50% of the dry weight
of the desiccant may be absorbed. For example, two to three hours
are used to absorb water vapor after one reposition of the desiccant
cartridge 20. It is estimated that one hour is needed for recharging,
but this time may differ as a function of various factors including
the amount of vacuum.
In other embodiments, the controller 34 also controls the vacuum
source 30. For example, the controller 34 turns the vacuum source
30 on or off in conjunction with actuation of the actuator 32 and
continued periodic actuation. In yet other alternative embodiments,
the controller 34 operates valves or switches to control the supply
of low pressure to the vacuum chambers 22 and 24.
FIG. 3 shows a flow chart of one embodiment representing the operation
of the climate control system of FIG. 2. The flow chart represents
one embodiment for exposing a desiccant to air within the passenger
compartment and a generating a low pressure to remove liquid from
the desiccant. In act 50 selection of a recirculation setting is
detected. In act 52 a temperature within the passenger is detected.
In act 54 the humidity within the passenger compartment is detected.
In alternative embodiments, any one or more of act 50 52 or 54
may be skipped. In response to activation of the recirculation setting,
a range of temperatures and range of humidities, a vacuum is applied
to the desiccant material. In act 56 application of the low pressure
by activating a pump, generating a Bernoulli effect, or positioning
a portion of a desiccant material within a vacuum chamber removes
liquid from the desiccant material. To further remove humidity from
air within the passenger compartment, the desiccant material is
shifted to expose recharged desiccant within the air in communication
with the passenger compartment in act 58. For example, silica desiccant
material is exposed to air within an air duct while another portion
of a desiccant material is exposed to a low pressure vacuum. Other
filtering may be provided in act 58 such as providing for carbon
activated filtering. Periodically as a function of time, detected
environmental conditions, or other inputs, the desiccant material
is shifted in act 58 so that recharged desiccant is exposed to air
associated with the passenger compartment and other portions of
the desiccant material are exposed to a low pressure for recharging
the desiccant.
FIG. 4 is a perspective view of another embodiment of the climate
control system 60. The climate control system includes a desiccant
system 62 and an air handling unit 64. The air handling unit 64
is adapted for mounting behind a dash board of an automobile. The
air handling unit 64 provides heated, cooled and/or filtered air
to the passenger compartment.
The air handling unit includes an inlet duct or vent 66. The inlet
vent 66 is adapted for drawing air from the passenger compartment
in to the air handling unit 64.
The desiccant system 62 connects to the inlet vent 66. In one embodiment,
the desiccant system 62 covers the inlet vent 66. The desiccant
system 62 comprises a housing 68 and two nipples 70. The housing
68 comprises metal, plastic, other materials or combinations thereof
The housing 68 contains two vacuum chambers and an air flow or air
duct section as described above with reference to FIG. 2. The air
flow section allows air to pass from the passenger compartment,
through the housing 68 and into the inlet vent 66.
In the embodiment shown, each vacuum chamber is associated with
one of the nipples 70. The vacuum from the vacuum source is provided
through the nipples 70. The desiccant is about 2/3 the length of
the housing 68. The desiccant slides between 1) exposing a first
half in the air flow section and placing a second half in one of
the vacuum chambers and 2) exposing the second half in the air flow
section and placing the first half in the other vacuum chamber.
While the invention has been described above by reference to various
embodiments, it will be understood that many changes and modifications
can be made without departing from the scope of the invention. For
example, any of various sources of vacuum and desiccant materials
may be used, whether now known or later developed. Additionally,
different relative sizes and shapes of various components of the
climate control system may be used.
It is therefore intended that the foregoing detailed descriptions
be understood as an illustration of the presently preferred embodiments
of the invention, and not as a definition of the invention. It is
only the following claims, including all equivalents, that are intended
to define the scope of this invention. |