Abstrict An apparatus and method for automatically regulating the environmental
system of a motorized vehicle and other articles having storage
compartments. As impinging air flow is directed through the cabin
or compartment subject to environmental control it comes in contact
with a desiccant filler contained within a desiccant wheel or canister.
The desiccant material absorbs moisture out of the air stream. The
resultant air stream, or the extracted moisture released into another
air stream, may then be directed to the interior of the motorized
vehicle or used in other parts of the system. The net effect is
a decrease or increase in the relative humidity level of the air
mass contained in the cabin or compartment of a motorized vehicle
or refrigeration unit. As one portion or element of the desiccant
filler becomes saturated, the other portion or element of the desiccant
filler completes it's regeneration cycle. The air streams are altered
so that the designated air stream remains in either the hydrous
or anhydrous desiccant, thus producing a constant air flow containing
either an increased relative humidity or an air stream with a reduced
relative humidity to achieve the desired result. The apparatus includes,
at least one moisture collection device having an inlet and an outlet,
and a system of flow conduits or paths into and out of the compartment
or cabin. The air streams may be directed to at least one heat exchanger,
a pre-cooler, a compressor, or an evaporator.
Claims What is claimed is:
1. A method of improving the efficiency of an air conditioning
system for a compartment of a motorized vehicle, comprising: (a)
providing a desiccant-based moisture collector; (b) dehumidifying
a first air stream by directing the first air stream through the
desiccant-based moisture collector, so that the first air stream
becomes a dehumidified first air stream; (c) after step (b), pre-cooling
the dehumidified first air stream! (d) after step (c), cooling the
dehumidified and pre-cooled first air stream with the air conditioning
system of the motorized vehicle, whereby less energy is required
for the air conditioning system to cool the dehumidified first air
stream than would have been required to cool the first air stream
prior to dehumidification; and (e) directing the dehumidified and
cooled first air stream into the compartment of the motorized vehicle.
2. The method of claim 1 wherein: in step (d), the cooling is
performed in a cooling device of a compressor based refrigeration
air conditioning system.
3. The method of claim 1 wherein: the pre-cooling includes transferring
heat from the dehumidified first air stream to a stream of outside
ambient air.
4. The method of claim 1 further comprising: regenerating the
moisture collector by passing a hot air stream through the moisture
collector and transferring moisture from the moisture collector
to the hot air stream.
5. The method of claim 4 wherein: in step (a), the moisture collector
comprises an enclosed canister; and further comprising directing
the first air stream and the hot air stream through the moisture
collector in an alternating manner.
6. The method of claim 4 further comprising: discharging the hot
air stream to the atmosphere.
7. The method of claim 1 wherein: in step (b), the first air stream
includes air from outside the compartment.
8. The method of claim 1 wherein: in step (b), the first air stream
includes air from inside the compartment.
9. The method of claim 4 wherein: in the regenerating step, the
hot air stream includes waste engine heat from an engine of the
motorized vehicle.
10. The method of claim 1 wherein: in step (a) the desiccant-based
moisture collector includes a relatively thin layer of solid desiccant
material on a honeycomb supporting structure so that the desiccant
material can rapidly absorb heat and give up heat.
11. The method of claim 3 wherein: in the pre-cooling step, the
transferring of heat from the dehumidified first air stream to the
stream of outside ambient air includes: transferring heat from the
dehumidified first air stream to an intermediate stream of heat
transfer fluid; and transferring heat from the intermediate stream
of heat transfer fluid to the stream of outside ambient air.
Description BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a method and apparatus
for both humidification and dehumidification through the use of
desiccant materials, as well as the automatic regulation of the
relative humidity of the air contained in motor powered vehicles
(hereinafter "motorized vehicles"), and the efficient
automatic elimination and prevention of frost, fog, or condensation
on the inside of the window glass of vehicles, and the elimination
and prevention of frost in refrigeration units.
2. Description of the Related Art
The invention provides features and benefits by controlling relative
humidity in a way not previously available. Automobiles, trucks,
vans, trains, boats, ships, military vehicles, aircraft, tractors,
motorized recreation vehicles, and various other types of motorized
vehicles have previously lacked a successful and economical method
or apparatus to automatically monitor and control the relative humidity
within the cabin of the vehicle.
Previously produced motorized vehicle environmental systems have
been developed to increase or decrease the cabin air temperature,
regulate the rate of air flow, filter dust or pollen particles out
of the air, defrost/defog the windshield, or reduce cabin noise,
but none of the environmental systems have attempted to economically
and effectively regulate the relative humidity level of the cabin
air. Although the environmental systems in some over the road trucks
have utilized water humidification and various dehumidification
methods in the past, the systems were either inefficient, unhealthy,
or expensive due to their initial installation cost, maintenance
requirements, or their high level of energy consumption. There are
currently desiccant based dehumidification systems for commercial
buildings, however, they do not use the same processes or methods
to provide a heat source for regeneration or the same configuration
of desiccant wheel that is used as an element of this inventive
method and apparatus, and none employ a canister like that shown
and claimed.
Traditional refrigeration and freezer units produce frost or condensation
within the box or on the evaporator coils when the humidity of the
air reaches the saturation point as the air is cooled in the unit.
The inherent frost problem restricts the air flow over the coils,
creates a frost buildup on the inside of the box, and limits the
efficiency of the coils. The current methods of defrosting these
types of units use additional energy and utilize expensive apparatus
to remove the frost.
In previously manufactured motorized vehicles the relative humidity
of the cabin has essentially been unmonitored, unregulated and uncontrolled
except through the use of traditional air-conditioner evaporator
units. The lack of humidity control of the cabin air in motorized
vehicle can have a negative effect on safety, comfort, health, and
operating efficiency.
In motorized vehicles the need for an efficient and effective way
to increase the relative humidity in the cabin to improve the comfort
for the occupants has existed for many years. If the motorized vehicle
is operating in cold weather without the addition of humidity into
the cabin air, the continued use of the heater in combination with
the introduction of cool dry fresh air from outside will cause the
relative humidity in the cabin to decrease to a point where the
occupants may become uncomfortable. Traditional humidification units
have experienced many problems due to the need to haul water and
health hazards are present from the growth of bacteria, mold and
mildew in the system.
In aircraft the problem is compounded because of the long duration
of the flight and the extremely low levels of humidity that occurs
in aircraft. In most long range commercial aircraft the cabin environmental
system is heated by compressed air taken from the compressor section
of the turbine engine. Outside air enters the engine air intake,
is compressed and thus heated by the compressor section of the engine.
Some of the hot compressed air going through the engine is vented
off from the engine prior to the air entering the burner section
of the engine. The hot air is then forced into the cabin environmental
system.
During most flights, the outside air has a low relative humidity
before it is heated, and the result of heating the air produces
an extremely low relative humidity when the air enters the cabin.
Even the moisture given off by evaporation from the occupant's perspiration
and from evaporation of moisture out of the occupants lungs is not
sufficient to keep the cabin at a high enough relative humidity
for it to be comfortable to the occupants. The moisture given off
by the occupants and generated from other sources escapes out of
the cabin as the stale cabin air is expelled from the cabin. Although
the cabin of a commercial aircraft may have the temperature regulated
very close to 70.degree. F., the relative humidity can drop to well
below 20%.
The CO.sub.2 in the cabin can cause discomfort for the occupants
when the CO.sub.2 reaches levels greater than 1000 ppm (parts per
million). This high level of CO.sub.2 exist because of the low percentage
of new fresh air brought into the cabin as compared to the ratio
of old stale air recirculated. The ratio of the fresh air is inadequate
to replace enough of the unwanted CO.sub.2. If the environmental
system circulates in more fresh air from outside to reduce the ratio
of CO.sub.2 and increase the ratio of Oxygen, the resultant air
mass would have an even lower relative humidity. This would produce
a relative humidity level even lower than the current uncomfortable
levels of less than 20%.
These extreme conditions cause the passengers to experience substantial
discomfort caused by two factors: 1.) stuffy feeling from poor ventilation
of fresh air; and 2.) dryness from extremely low relative humidity.
The effects of these two factors manifest in the physiological conditions
for the occupants as respiratory irritation, headaches, and fatigue.
These same factors also effect the flight crew and impact the safe
operation of the aircraft due to the crew member's distraction from
the effects of high CO.sub.2 and low relative humidity.
In aircraft design, there has always been strong economic pressure
to reduce the operational cost by reducing the cost of fuel. The
weight of the aircraft has a direct relationship to the consumption
of fuel. For each pound of cargo which must be reduced to off set
an additional pound of aircraft weight there is a penalty due to
the loss of revenue for the pound of cargo and the additional cost
of fuel to transport the extra weight added to the aircraft. If
an inventive apparatus is installed in the aircraft, the weight
of the apparatus is added to the total air frame weight. Of course,
the additional weight of the apparatus will have a long term operational
cost disadvantage simply due to the weight of the apparatus installed
in the aircraft. The benefits of passenger comfort must off set
the cost penalty of initial unit cost and long term operational
fuel cost. The cost benefit of lower aircraft weight due to the
conditioning of the air in the cabin is a respectable trade-off.
It is commonly understood that water is heavier than air. What
is not commonly understood is that water vapor is lighter than air.
Since the inventive apparatus adds water vapor to the air contained
in the cabin the apparatus is actually reducing the weight of the
aircraft by reducing the weight of the cabin air. Air is made up
of: NITROGEN 78% (NI) with 14.0067 AMU (Atomic Mass Units); OXYGEN
21% (0) with 15.9994 AMU and OTHER GASES 1% which consist of: ARGON
0.9%, CARBON DIOXIDE 0.03% and varying amounts of WATER VAPOR Since
CARBON has an AMU of 12.011 the combined molecule of CARBON DIOXIDE
with CARBON: 12.011 and OXYGEN: 15.9994 is actually lighter than
OXYGEN alone with 15.9994. This would provide the designer with
a marginal incentive to increase the CARBON DIOXIDE content in the
air mass of the cabin to reduce the aircraft weight. When OXYGEN
15.9994 is combined with two (2) HYDROGEN 1.00794 AMU atoms the
result is a molecule with a much lower weight. Much lighter than
NITROGEN, OXYGEN, or CARBON DIOXIDE.
When water vapor is added to the cabin air mass unlike CARBON DIOXIDE
the passengers experience more healthful and comfortable breathing
and a significantly greater reduction in air mass weight. The evaluation
of the apparatus must consider not only to the comfort and safety
of the occupants, but also the offset in weight reduction from the
water vapor displacement of the heavier cabin air gasses. Many people
working with desiccants will refer to removing a given amount of
water from an air mass, and the values given may be pounds of water
or gallons of water, what they fail to mention is the water vapor
removed is replaced by a heavier air mass.
It is not practical for the aircraft designers to simply modify
the aircraft environmental systems by adding a conventional liquid
humidification apparatus which would increase relative humidity
in the cabin air with an atomized spray of water into the vent system
to perform the needed humidification. The addition of a water based
humidification system would only create a new set of problems. These
problems include the added cost of transporting the liquid water,
the additional maintenance expense to keep the system clean and
operating properly, and health concerns related to bacteria growing
in the wet area of the system.
The cabin environmental systems for today's commercial aircraft
were designed to use a minimum amount of energy from the engines
by simply recirculating more old stale cabin air and adding less
fresh air from outside the aircraft. The fresh air from outside
is brought into the aircraft by bleeding off heated compressed air
from the compressor section of the engine (bleed air). In today's
large long haul aircraft cabins, the manufactures have traded off
passenger comfort and health for fuel efficiency which has created
unhappy passenger with a strong desire for better comfort and a
more healthful environmental system.
There is a significant need to develop a method to economically
and safely humidify the fresh outside air which is forced into the
cabin. If aircraft cabin environmental systems had the capability
to increase the humidity in the cabin, this would not only solve
the current problem with the existing low level of relative humidity,
this would also enable the system designers to increase the ratio
of fresh air introduced into the cabin without causing a severely
negative impact on the relative humidity level of the cabin air.
For the environmental system to bring more fresh air into the cabin,
the designers must consider the following factors, including, but
not limited to: 1.) the need to compensate for additional heat from
the added fresh air to maintain the cabin temperature of 70.degree..
2.) the effects from a larger volume of fresh air on maintaining
the correct level of cabin pressure. 3.) the requirement for additional
humidification of the additional fresh air to correct for the lower
relative humidity.
Since the aircraft engine compressor system has the capability
to provide larger volumes of fresh air that is both heated and compressed
the modification to these elements of the existing environmental
systems would be minimal. The remaining system deficiency, which
is the lack of relative humidity control, would require the incorporation
of a new humidification system.
Although aircraft experience the most severe cabin environmental
problems related to low relative humidity, all other closed cabin
motorized vehicles including but not limited to cars, trucks, busses,
boats, military vehicles, trains, etc. experience similar low humidity
problems of varying degrees. Many occupants of land motorized vehicles
experience discomfort from low relative humidity in the cabin. The
operators of overland trucks, individuals spending long duration's
of time in automobiles, busses or other motorized vehicles experience
discomfort from extremely low relative humidity due to the effect
of operating the cabin heater for extended periods.
Just as most motorized vehicles have the need to regulate the temperature
for passenger comfort by either increasing or decreasing the environmental
air temperature and rate of air flow in the cabin, there is also
a need to control the percent of relative humidity of the cabin
air to provide an acceptable level of comfort.
Existing motorized vehicles lack an effective dehumidification
system, they have three significant reasons why this improvement
is needed: 1.) Safety could be enhanced by eliminating windshield
fog/frost; 2.) Comfort for the occupants could be improved by controlling
the maximum level of relative humidity; and 3.) Efficiency in the
operation of the motorized vehicle from a reduction of fuel consumption
could be attained due to the reduction of energy consumption of
the existing air-conditioning system since the current method of
dehumidification expends additional compressor energy on the condensation
of moisture on the evaporator coils of the traditional air-conditioner.
Motorized vehicle operation safety is believed to be significantly
enhanced by this invention due to the automatic prevention or rapid
elimination of visual impairment or obstruction from condensation,
fog, or frost on the inside of cabin windows of motorized vehicles
(e.g. cars, trucks, boats, helicopters, tractors, trains, military
equipment, airplanes, etc.)
Motorized vehicles have for years experienced window/windshield
condensation under certain environmental conditions. The closed
area of the cabin, along with the occupants breathing out moist
air, and in some cases rain soaked clothing tends to rapidly produce
condensation on the inside of the glass of the windows. Condensation
has been known to accumulate during the operation of a motorized
vehicle when the inside cabin air temperature and high relative
humidity of the cabin combines with the cold window glass to produce
windshield fog/frost.
Traditional cabin defrost/defog systems provide the operator with
the option to switch to outside air and/or increase the inside cabin
temperature to remove the condensation. This method of defrost/defog
attempts to eliminate the condensation by introducing outside air
with a lower level of humidity and/or change the inside air temperature,
or the temperature of the window glass, to avoid having the inside
air reach the due point. Another traditional approach, that consumes
additional fuel, is using the air-conditioner evaporator to defrost
the windshield while the heater is operating to warm the cabin.
The net result of these systems is the occupants must take the
necessary actions to attempt to eliminate the condensation, and
the comfort of the occupants may also be sacrificed so as to eliminate
the condensation. In these situations, safe operation of the motorized
vehicle could be jeopardized because the corrective action to eliminate
the condensation does not usually begin until the occupant can see
the condensation, which is often after the operator's vision is
already impaired. The operator must then adjust the environmental
controls by attempting to set the climate controls to a setting
which will eliminate the condensation. If the operator makes the
adjustment incorrectly the window may actually accumulate more condensation
and create a more serious unsafe condition, such as when the operators
vision through the windshield or other windows is completely blocked
by condensation.
There are times when the introduction of outside air is undesirable
to the occupants of the cabin, such as when the motorized vehicle
is passing through smog, exhaust filled environments, or in the
presents of other anxious gases or fumes. Most of the current methods
attempting to eliminate condensation are only adaptations to the
conventional heating and cooling units and neither of these systems
have the distinct capability to effectively control both the cabin
relative humidity and temperature. For example, on high humidity
days with rain soaked occupants entering the motorized vehicle the
systems must rapidly eliminate the condensation from the windshield.
As the cabin air mass warms up the moisture from the clothing begins
to evaporate into the air as the warmer air mass increases it's
capability to hold moisture. The warm moisture saturated air is
cooled when it comes in contact with the inside surface of the windshield
glass which causes the moisture to form condensation on the surface
of the glass. Many environmental control systems of motorized vehicles
do not have the capability to immediately eliminate or prevent the
formation of condensation on the windshield under these conditions.
Since the definition of environmental air-conditioning is not limited
to just cooling when considering occupant comfort, the definition
also encompass temperature, air motion, moisture levels, radiant
heat levels, dust, various pollutants, sound, and microorganisms
when considering the total cabin environment air conditioning. Relative
humidity control should be a major element of the overall system
design. Although many of the cabin environmental systems in today's
motorized vehicles have been improved to include automatic temperature
and air volume movement (CFM) control settings, manufactures have
not incorporated into climatic control systems the capability to
automatically and efficiently increase or decrease the relative
humidity level in the cabin.
The human body regulates it's temperature of 98.6.degree. F. during
different levels of physical activity. The metabolic rate of an
individual is based on the activity level of the individual. The
human body tends to be comfortable in a temperature range of 67.degree.
F. to -72.degree. F. in Winter and 73.degree. F. to -79.degree.
F. Summer. With the body continuously giving off heat @ 98.6.degree.
F. to the surrounding air mass with 70.degree. F., the body regulates
the rate of heat emission to maintain a constant 98.6.degree. F.
The body metabolic rate while sleeping is 0.7 while driving a car
1.5 while walking 2.6 and during competitive sports 8.7. The higher
the metabolic rate, the more heat the body needs to give off to
maintain 98.6.degree. F. The body controls it's temperature by controlling
the emission of energy from the body by radiation, by convection
to air currents that impinging on the skin or clothing, by conduction
of clothing and objects that are contacted, and by evaporation of
moisture in the lungs and of sweat from the skin.
Evaporation and convection heat loss are functions of air temperature
and velocity. Evaporation is a function, in addition, of relative
humidity. Air-conditioning (A/C) cooling units for traditional motorized
vehicles primarily use convection heat loss to maintain the comfort
for the occupants of the cabin. These A/C cooling units do not have
the capability to lower the relative humidity much below the saturation
level to enhance the human body's natural cooling effect from evaporation.
In the existing motorized vehicles equipped with environmental cooling
units, when the occupants wants faster cooling, they must lower
the unit's temperature setting, increase the air flow volume to
maximum, and set the unit's air flow to recirculate. These settings
may increase the body's cooling rate, but they also create an uncomfortable
cold clammy feeling for the occupants if the cabin has a high relative
humidity. If the relative humidity exceeds 60% the occupants feel
wet.
For example, when the temperature is below 70.degree. F. and the
relative humidity is in excess of 60% the occupant feels clammy-cold,
and with a high relative humidity and the temperature above 77.degree.
F. they feel sticky-hot. There are many times when the occupants
may be operating the A/C cooling unit because they feel uncomfortable
even when the cabin temperature is below 70.degree. F. due to a
relative humidity above 60%.
If the environmental control unit had the capability to independently
control the relative humidity the occupant would feel comfortable
using a smaller volume of cool air and would actually operate the
compressor cooling unit less often.
The air-conditioning cooling units in today's motorized vehicles
are both mechanical (belt) driven and electrical powered from the
engine. The air-conditioner system places an additional load on
the engine that decreases the motorized vehicle's acceleration performance
and increases the engine's fuel consumption. The lack of efficiency
in the air-conditioner equates into higher fuel cost of operating
the motorized vehicle and lower performance.
Since today's motorized vehicle's environmental systems lack the
capability to lower the relative humidity before the air passes
over the cooling coils, the air-conditioner must use additional
energy to condense out the moisture when the air has a high relative
humidity. The condensing out of the moisture on a high temperature,
high humidity day causes the unit to expends approximately 20% to
30% of it energy performing this conversion of water vapor to a
liquid. As the air temperature is lowered with a high relative humidity
it passes over the cooling coils and the moisture will condense
out as the air approaches the dew point. The condensation produced
from this cooling can create wet areas within the air-conditioner
unit where dangerous bacteria can grow and then spread into other
areas of the system or cause the inside of the motorized vehicle
to smell like mildew. If the cooling coils are below 32.degree.
F. the condensation will form frost on the coils.
Most available units are designed to maintain the cooling coil
temperature at about 35.degree. F. to eliminate the build up of
ice on the coils. The air-conditioning unit's air cooling output
is limited by it's ability to lower the air's temperature because
of this minimum temperature limit on the coils of 35.degree. F.
If the relative humidity in the air passing over the coils could
be lowered, the dew point of the moisture in the air would be lower
and the condensation would not form until the air reached a much
lower temperature, or if the relative humidity is low enough it
may never form frost when the air passes over these cold coils.
Since the units are limited by the 35.degree. F. coil temperature
the cold air output of the unit cannot be lower than the temperature
of the coils without a frost build up, therefore, the systems are
designed to put out larger volumes of air (Cubic Feet/Minute) to
accomplish the necessary cabin air cooling. Moving larger volumes
(CFM) of air requires greater energy consumption.
The currents systems are noisy and the blast of cold air on the
occupants produce an unpleasant cabin environment. Since these systems
produce cold moist air the occupants will set the temperature lower
because the occupant's own body is not benefiting by the potential
cooling effect from the body's natural evaporation that could be
gained with a lower relative humidity of the air stream entering
the cabin. Since the air-conditioners lack the capability to lower
the relative humidity without operating the compressor the occupants
will turn on the air-conditioner more often because they feel uncomfortable.
The occupants could be perfectly comfortable with a higher cabin
temperature if the relative humidity were lower.
In summary, high fuel consumption in the current environmental
systems is believed to be largely the result of: 1.) having to move
more CFM of air to accomplish the necessary cooling; 2.) minimum
cooling coil temperature of 35.degree. F.; 3.) the occupants will
set the desired temperature lower than necessary for comfort due
to high relative humidity; 4.)the occupants will use the unit more
often for comfort; and, 5.) cooling moist air requires more energy
than cooling dry air;.
Substantial savings in fuel consumption of motorized vehicles could
be obtained if cabin environmental units could efficiently lower
the relative humidity to a comfortable level in the cabin air.
Conventional systems do not have the capability to perform both
the humidification and dehumidification function utilizing the same
elements of their apparatus. Many times the environmental system
is operating the heater while the air-conditioning cooling is operating
to eliminate windshield condensation; and few if any, vehicles have
the capability to effectively dehumidify the cabin air.
Many motorized vehicles and trailers pulled by motorized vehicles
have refrigeration or freezer units to keep the contents of the
trailer or truck cold or below freezing. Most freezer equipment
has been designed to go through a defrost cycle to eliminate the
frost. The defrost cycles consist of a heating cycle in most cases
to melt the frost that has formed on the coils. These defrost cycles
are inefficient due to the heating and re-cooling required to perform
the defrosting. Some units have duel coils to allow one to defrost
while the other coil is cooling. None of these units has the capability
to regulate the relative humidity other than through the current
methods of using the cold evaporator coils to condense out moisture,
or allow the build up of frost and then melt the frost thereby allowing
the water to drained to the outside of the unit. A large amount
of energy is expended by these units to remove frost and moisture.
SUMMARY OF THE PRESENT INVENTION
The invention automatically regulates the environmental system's
impinging air flow through a desiccant coated materials and in this
way the moisture is adsorbed out of the air stream into the desiccant
or moisture is released out of the desiccant material into another
air stream to produce either a decrease or increase in the relative
humidity level of the air mass contained in a motorized vehicle
or refrigeration unit. The designated air stream passing through
the desiccant material is periodically altered by the process to
continually direct the air stream into either a hydrous or anhydrous
desiccant material.
The process and apparatus preferably achieve a system balanced
so as one element of desiccant becomes saturated, the other element
of desiccant completes it's regeneration cycle, the air stream is
altered so that the designated air stream remains in either the
hydrous or anhydrous desiccant, thus producing a constant air flow
containing either an increased relative humidity or an air stream
with a reduced relative humidity to achieve the desired result.
The cycling of the air flow over the desiccant is automatically
controlled to alternate between different sections of a desiccant
wheel or between different desiccant canisters to achieve a continuous
adsorption and regeneration process.
An important element of the desiccant wheel or desiccant canister
filler is the desiccant coated on a honeycomb or similar structured
material creating the air flow passages providing the even distribution
of the air stream over the surface of the desiccant. The surface
of the air flow passages are coated with a desiccant material so
as to expose the air stream to the maximum available surface as
it passes through the structure with a coating of hygroscopic material
such as lithium chloride, titanium silicate, or other desiccant
material capable of adsorbing moisture out of a cool air stream
and which is also capable of releasing the moisture through evaporation
when a hot air stream passes through the passages.
The titanium silicate desiccant which is produced by Engelhard
Corporation has the capability to effectively adsorb moisture at
room temperature and release moisture to regenerate the desiccant
through evaporation at 140.degree. F. The process of alternating
cycles of air sources over the desiccant material enables the system
to reuse the desiccant and continuously function over an indefinite
period of time. One of the unique features of this process is that
it utilizes as a source of regeneration energy (in most embodiments
of the apparatus and under most environmental conditions) the available
heat energy from the heating system, and/or excess heat energy from
the engine, and/or excess heat from the air-conditioner compressor
and coils to perform the desiccant regeneration.
The inventive process efficiently utilizes desiccants to counteract
the inherent environmental conditions of low relative humidity when
an air mass is heated and a high relative humidity when the environmental
air-conditioning cooling unit is operating. The invention also automatically
removes/prevents fog, frost, or condensation from the windshield
of a motorized vehicle, and prevents the build up of frost in refrigeration
unit through desiccant dehumidification. In addition the apparatus
automatically regulates the desired relative humidity of the air
mass to a level set either automatically or manually on the digital
automatic control unit of the apparatus while the environmental
air-conditioning cooling, heating, or refrigeration unit is on or
off and with the airflow selector set to recirculate or fresh air.
The intended functions are performed automatically through variations
in air flow over desiccant materials and/or the mechanical relocation
of desiccant materials as various air streams flows through the
apparatus. The inventive method and apparatus removes or adds humidity
to an air stream. When cool air passes over the desiccant surface,
moisture from the cool air is adsorbed into a desiccant material.
After the air stream is altered and/or the desiccant is repositioned
automatically by the system, a hot air stream is employed to release
the moisture from the desiccant into the hot air stream by evaporation
as the hot air stream passes over or through the desiccant material.
The desiccant regeneration occurs when a hot air stream changes
the desiccant from hydrous to anhydrous by evaporation as a hot
air stream passes through a desiccant material that is either adhered
to the surface of a honeycomb structure of NOMEX; or the desiccant
is adhered to a material similar in shape to the honeycomb, such
as rolled corrugated card board; or a combination of desiccant and
structural materials making up the structure of a canister filler
or desiccant wheel; all of which are here after referred to as honeycomb.
The air streams is alternately passed through either a desiccant
coated honeycomb canister filler or a portion of a desiccant coated
honeycomb wheel. After the moisture is adsorbed into the desiccant
during the cool air cycle, the desiccant on the honeycomb structure
is repositioned or the air stream is altered to cause a hot air
stream to pass through the structure resulting in the evaporation
of the moisture into the hot air stream thus causing the desiccant
to release the moisture into the hot air stream which increases
the relative humidity. Through this method the moisture can be removed
from one air mass and then transferred into another air mass by
a process of adsorption of moisture into the desiccant material
and then followed by the evaporation of the moisture out of the
desiccant material into another air stream.
The inventive method and apparatus has the ability to automatically
regulate the environmental conditions including the level of relative
humidity of the cabin air of a motorized vehicle, or the air contained
in a refrigeration unit. The automatic control unit, which is an
essential component, monitors internal and external environmental
factors and when necessary activates the appropriate process where
the air is conditions by controlling the apparatus and process to
provide comfort for the occupants, automatic defrosting/defogging,
and operational efficiency. The sequence of process steps, mechanical
actions, and airflow is automatically regulated by the automatic
control unit of the apparatus.
When dehumidification is required the process of adsorption of
moisture out of the cabin air stream is activated by directing a
cool air stream through the desiccant material which causes the
moisture to transfer to the desiccant. The cool air stream enters
the cabin as dehumidified air. After dehumidification has been accomplished
the air temperature may be further conditioned by either raising
or lowering the temperature before the air goes into the cabin.
The second phase of the process of dehumidification is the removal
of the moisture from the desiccant to regenerate the desiccant and
prepare the desiccant for another adsorption cycle. The removal
of the moisture from the desiccant is accomplished by evaporation
when a hot air stream passes through the hydrous desiccant causing
the moisture to transfer into the hot air stream by evaporation
which is then expelled from the apparatus.
Humidification of the cabin air is accomplished in a similar process
which is simply reversed, with the hot air stream going to the cabin
as opposed the cold air stream. The hot humid air stream may also
be further conditioned to regulate the air temperature before the
air enters the cabin. The process is automatically controlled and
performed efficiently since the heat required for regeneration is
supplied from excess engine heat or excess heat from the air-conditioner
cooling unit. The process provides a benefit when humidity is added
to a heated air mass and moisture is removed from a cooled air mass.
The apparatus may also independently alter the relative humidity
of the air stream when the cabin heating and air-conditioning cooling
unit is not activated.
The inventive apparatus size, air flow sequence, desiccant element
size and shape, case type, and specific functions may vary to meet
the specified needs of the motorized vehicle. Although the different
alternatives, methods, apparatus, and configurations describe herein
as best suited for preferred applications this in no way limits
the invention from using variations of the alternative processes,
described methods, apparatus and variations of configurations of
the apparatus which are described herein.
In the large commercial aircraft the embodiment may consist of
a unit containing a desiccant wheel or an adaptive canister case
system consisting of various shapes and quantities of canisters
depending on the requirements of the current cabin environmental
system, availability of compartment space and cabin layout. The
apparatus may be designed into a new motorized vehicle or adapted
to an existing design vehicle already produced where the apparatus
is an after market unit adapted to an operating motorized vehicle.
While an aircraft is loaded with people on the ground in hot humid
climate before take off the cabin may need dehumidification to maintain
passenger comfort. When an aircraft is on the ground the inventive
apparatus may perform dehumidification from a ground unit connected
to the aircraft by flexible duct hoses. While the aircraft is in
flight a variation on the apparatus may provide humidification for
the cabin fresh air supply by increasing the relative humidity of
the hot compressed air provided by the engine to the cabin.
Some smaller aircraft may use only an apparatus with the automatic
dehumidification function to defog/defrost the inside of the cockpit
windshield glass. In each case the apparatus is using variations
on the basic inventive methods to perform the intended function
described herein and a particular embodiment may include one or
more of the features described.
The automatic control of relative humidity provides comfortable
and healthful air for the occupants, safety for the operator of
the motorized vehicle by automatically eliminating or preventing
fog/frost (condensation) on the inside of the windshield, and efficiency
to the air-conditioning unit both in size and energy consumption.
Efficiency in operating the apparatus is attained through the inventive
methods that utilize in most cases, excess heat normally expelled
into the atmosphere or through redirection of the conventional heating
or recirculating air sources through the apparatus. The invention
does not requires an external (liquid) water source to humidify,
nor does it produce a (liquid) out put of water within the apparatus
while it is dehumidifying.
The humidification of the aircraft cabin air is accomplished by
the inventive method of passing the stale cabin air containing moisture,
through the desiccant coated honeycomb material where the moisture
in the cool air is adsorbed into the desiccant material before the
stale air is ejected from the aircraft. During the circulation of
fresh outside air into the cabin and before the release of stale
cabin air, the moisture in the stale air is extracted by a desiccant
material as the stale air is allowed to flow out through the desiccant
wheel or canister and the moisture is adsorbed into the desiccant
material, then the air flow to the moist portion of the desiccant
is altered to allow the fresh hot air to pass over the moist desiccant
material to receive the moisture contained in the desiccant when
the heat in the hot air causes the moisture to evaporate out of
the desicant.
The alternation of the desiccant cycle is accomplished when the
desiccant material collecting moisture from the stale moist cabin
air approaches the saturation point, the apparatus alters the air
flow so as to position the desiccant where a stream of hot fresh
air, from the compressor section of the engine, used for heating
the cabin will pass over the surface of the desiccant material.
The fresh hot dry air from the compressor section of the engine
or any other heated air source will cause the moisture in the desiccant
to evaporate into the hot air stream. The resulting moist fresh
hot air is directed into the cabin to provide the passengers with
a comfortable environment thus eliminating the problem of dry cabin
air without the need to transport water and utilize conventional
humidification methods.
In summary, on long high altitude flights, the desiccant material
removes the moisture from the stale cabin air before the air is
ejected from the aircraft. The desiccant is repositioned into a
hot air stream and then releases the moisture back into the fresh
hot air from the engine compressor before the air goes into the
cabin. A heat exchanger may be used to regulate the temperature
of the hot moist air before it enters the cabin.
The inventive apparatus may consist of two different types of desiccant
assemblies: a desiccant wheel or a desiccant canister.
A desiccant wheel is preferably constructed of NOMEX honeycomb,
rolled corrugated cardboard, or similar structure wheel consisting
of a light weight structure allowing air to freely pass through
the wheel with a coating of desiccant on the r of the structure
to provide the maximum surface area exposed to the air flow or a
material with desiccant integral to the structure or a combination
of both coated and integral desiccant. The smaller wheels may have
a center torque drive and the larger wheels may have either a center
torque drive or a perimeter belt and pulley drive system to slowly
rotate the wheel.
A desiccant canister is preferably constructed of NOMEX honeycomb
or similar structured material contained in a case of metal, plastic,
or other structural material. The honeycomb is positioned in the
case to allow the air to flow into the case through an input opening
in the case where the air passes through the tubular structure of
the honeycomb then out of the output opening of the case. The input
and output openings are connected to a rotary air valve, slide air
valves or damper type valves to alternate the airflow's between
a pair of canisters. As one canister completed the adsorption cycle
and the other canister completes the evaporation cycle the valve
changes the air flow between the canisters. Additional pairs of
canisters may be provided to level the air pressure in the line
during cycle changes and offer greater system capacity.
The process is automatically controlled by the electronic control
unit through sensors measuring temperature and relative humidity
within the apparatus and also external to the apparatus, and then
automatically regulating the desired relative humidity level in
the cabin by activating the humidification process to add moisture.
The control unit may stop the process by either turning off the
power to the desiccant wheel rotary torque motor or by not recycling
the crossover valve and allowing the air stream to continue to flow
through the same desiccant canister after it is saturated or regenerated.
The apparatus has air filters to prevent a build up of dust, dirt,
or foreign matter on the surface of the desiccant material.
In addition to the inventions standard method of aircraft cabin
air humidification by removing moisture from stale air before it
is expelled, the method may be expanded to include another source
of moisture from the ambient (outside) air. The outside air is used
as an additional source from which moisture is also adsorbed by
the desiccant as the outside air flows through the apparatus. After
the desiccant adsorbs the moisture out of the ambient air source,
the dry air is then expelled back to the outside atmosphere.
The automatic control unit of the apparatus determines when the
cabin relative humidity needs to activate the duel air sources for
humidification. This may only be necessary when the apparatus is
unable to obtain enough moisture from it's primary source of moisture
by reclaiming cabin moisture. Since the moisture will be adsorbed
out of the outside air with a significantly lower pressure as compared
to the inside cabin air which is at a higher pressure the apparatus
must have a seal system to prevent the cabin air from escaping into
the outside atmosphere. The canister type system has many advantages
for this application.
In motorized vehicles where cabin air pressure is not a factor
but the need for duel moisture sources exist the inventive apparatus
can produce the desired results from a single unit utilizing two
different stages or portions of a cycle of the same desiccant to
perform both outside air moisture adsorption and stale air adsorption
into the desiccant material that will be evaporated out of the desiccant
for humidification of cabin air.
Humidification of the cabin air for land or water motorized vehicles
is performed through a method of desiccant humidification where
moisture is adsorbed out of stale cabin air before it is expelled
from the motorized vehicle or the moisture is extracted from outside
air and then evaporated into the air stream entering the cabin from
the heater. The hot air source used to perform the evaporation may
be either recirculated cabin air or fresh outside air. The humidification
is accomplished without the need to transport water or spray a fine
mist of water into the impinging air stream or the process of passing
the air stream through a water saturated mat. If the temperature
required to evaporate the moisture from the desiccant is higher
than the desired cabin heat temperature, and the result of the evaporation
of the moisture is also a temperature higher than is desired by
the occupants of the cabin, then a heat exchanger (pre-cooler) is
activated by the control unit to lower the temperature of the moist
hot air before it enters the cabin. The automatic control unit senses
the cabin's relative humidity and compares the sensor readings to
the level set on the digital automatic control unit. The level may
be automatically set by the control unit or manually set by the
occupants of the motorized vehicle, if the control unit senses the
need to increase the relative humidity to meet the desired relative
humidity the control unit activates the apparatus to add humidity.
If the control unit senses that the relative humidity has reached
the desired level set on the control unit the system automatically
deactivates the humidification function of the apparatus. When the
automatic digital control unit senses that the relative humidity
of the cabin is higher than desired level the system automatically
activates the dehumidification functions of the unit. The automatic
control unit which is also connected to the environmental heating
and cooling system may further condition the air before it enters
the cabin to regulate the temperature level and air flow volume
(CFM).
Desiccant based dehumidification is a component of the inventive
method used as an element of the cabin environmental system providing
comfort for the passengers and is usually associated with the boarding
of the aircraft and during the time from ground operations to shortly
after take off, usually before the cabin heat system has started
to lower the relative humidity in the cabin after takeoff.
Many times during boarding passengers experience discomfort from
high humidity due to the physical exertion of boarding the aircraft
in conjunction with a hot humid external atmosphere, where the relative
humidity level of the cabin can exceed 80%. Dehumidification of
the cabin air during these conditions can significantly improve
the comfort of the crew and passengers. During passenger loading
and unloading, ground operations (taxi & waiting for take-off),
and other times the when cabin environmental cooling is necessary,
the cabin air dehumidification may either be supplied by an on-board
units or ground units which lower the relative humidity on hot and
muggy days to provide passenger comfort when conditions cause high
relative humidity in the cabin. As passengers board the aircraft
and exert the effort to store baggage, they often start to sweat
and add to what may already be a high relative humidity for the
air mass in the cabin. The addition of a safe and efficient environmental
system with humidity control capability will greatly improve the
comfort of the passengers during loading, ground operations, and
early in the flight.
The dehumidification of the cabin air is also believed to significantly
improve the efficiency of the air-conditioner cooling by removing
the moisture before the evaporator coils experience the additional
load required to condense out the moisture on a high relative humidity
day.
Dehumidification of motorized land or water vehicle's cabin air
is performed through a method of desiccant dehumidification where
recirculated cabin air passes through NOMEX honeycomb or similar
structure material coated with desiccant of either a wheel or canister
type which adsorb the moisture out of the air as it passes over
the desiccant material coated on the surface of the structural material.
The desiccant may also be part of the structural material and/or
imbedded in the structure of the wheel or canister. The desiccant
may also be placed or injected into a rounded, square, or rectangular
shaped tube positioned within the center of a larger honeycomb tube
structure. The apparatus is also capable of dehumidifying fresh
outside air before it enters the cabin. The wheel or canister is
regenerated and prepared for the next adsorption cycle when a hot
air stream is directed through the desiccant material to evaporate
off the moisture contained in the desiccant.
The excess heat of the engine provides the heat used to regenerate
the desiccant and prepare the desiccant for the next adsorption
cycle. Any one or combination of the engine's heat producing systems
such as the engine coolant fluid, oil cooler, exhaust manifold,
catalytic converter, exhaust pipe, air-conditioner coils or other
heat sources may be use either individually or collectively as a
heat source to evaporate the moisture contained in the desiccant.
The system is controlled by an automatic digital control unit where
the occupant sets the desired relative humidity level or the automatic
control unit establishes the desired relatively humidity and the
unit automatically selects the necessary process configuration,
activates the necessary components of the apparatus and continues
to operate until the desired relative humidity level is reached
after which the apparatus is turned off by the automatic control
unit.
In some applications, the automatic control unit also continues
to operate the regeneration side of the system after the engine
is turned off to prepare the desiccant for the next time the motorized
vehicle is started. In this case the residual excess engine heat
remaining in the engine and exhaust system after the engine is turned
off is used to regenerate the desiccant and then the desiccant is
isolated from any outside moist air by doors or air valves that
close to prevent unwanted moist air from coming in contact with
the anhydrous desiccant while the vehicle in not in use. The residual
regeneration feature provides for immediate windshield defog/defrost
the next time the engine is started.
The visibility of the pilot and crew while operating a large commercial
airliners, small private airplanes, or helicopters is extremely
critical to the safety of the aircraft. Visual impairment of the
flight crew or pilot distraction while attempting to clear windshield
condensation can directly contribute to the aircraft safety. The
lives on board the aircraft and others on the ground that could
be injured by a crash are dependent on the pilot's ability to see
clearly outside, especially during landing and take off.
The apparatus uses an automatic control unit that electronically
monitors relative humidity sensors and windshield temperature sensors
to automatically activate the desiccant dehumidification system
prior to the formation of condensation on the windshield, thereby
preventing condensation from ever forming on the windshield. The
automatic functioning of the apparatus relieves the pilot of ever
having to take any actions to clear windshield of fog, frost, or
condensation. Operational safety is enhanced since the pilot is
relieved of the possibility of distraction from windshield condensation
or the need to make equipment adjustments to eliminate windshield
fog or frost.
The operation of the aircraft apparatus is similar to that of the
land and sea motorized vehicles apparatus with the exception that
the source of heat in most cases will be transferred to the apparatus
via a hot air stream as opposed to coolant fluid.
This invention, through the use of a desiccant dehumidification
system, automatically lowers the relative humidity of the inside
cabin air; thereby, preventing or eliminating windshield condensation.
The present invention provides an automatic cabin humidity control
system which prevents condensation, frost, or fog from forming on
the inside surface of the windshield. The invention may also include
optional sensors to detect the exterior temperature and humidity.
For example, when the temperature and humidity approach (the saturation
point) a level where condensation may form on the windows an automatic
controller activates the desiccant dehumidification system. The
automatic control unit sends electrical current to the cabin chamber
fan, the rotary motor, the hot chamber fan, and the engine coolant
valve to move it to the open position for a desiccant wheel type
of apparatus. For the canister type apparatus, a variation of the
process where the desiccant wheel is replaces by a set of desiccant
canister, the automatic control unit activates fan motors to move
the air flow through the desiccant canisters and begins to alternate
the air streams between the duel canisters by periodically activating
the crossover valves to regulate the dehumidified air flow to the
inside of the windshield glass. The air stream is dehumidified when
it passes through the anhydrous desiccant material. As the desiccant
material in the canister becomes saturated with moisture the control
unit alternates the air flow by activating the input and output
crossover valves to redirect the air flow through another canister
that has completed the evaporation (regeneration) cycle. Heat exchangers
are arranged to heat or cool the various air streams when necessary
both before and after the air passes through the desiccant material.
The apparatus directs a stream of dehumidified air "dry air"
toward the windows to evaporate existing condensation that may exist,
or prevents the formation of new condensation. Additional heat may
be applied to the air stream after dehumidification to accelerate
the removal of condensation on the interior and melt ice or snow
on the exterior of the glass. The apparatus is designed to reduce
the humidity of the cabin air near the windows and continue to remove
humidity (moisture) until the humidity level reaches a desired level
within the cabin. Since the regeneration of the desiccant wheel
or canister is preferably accomplished by using the excess heat
from the engine, the only additional energy necessary to operate
the apparatus is in the form of electrical energy to operate the
controls, motors, and valves.
Although the desiccant system may use some of the existing air
ducts and vents design for the heat and air-conditioning system
to deliver dehumidified air, the inventive apparatus and method
are designed to function independently, such as those times when
the need to cool or heat the cabin does not coincide with the need
to reduce the relative humidity.
The inventive apparatus and system can be summarized in a variety
of ways, one of which is the following: an apparatus and method
for defrosting or defogging the interior portion of a windshield
with an impinging air stream, wherein the windshield surface to
be defrosted or defogged is contained within the cabin compartment
of a motorized vehicle, wherein the apparatus comprises: a rotary
desiccant wheel, a driver to rotate the wheel, a heat exchanger
(or other heat source), a case having an interior to house the desiccant
wheel, a first fan for drawing air from the cabin compartment of
the motorized vehicle and forcing the air through the desiccant
wheel to the upper section of the cabin side chamber of the case
and back to the cabin of the motorized vehicle, and a second fan
for pulling an air stream through a heat exchanger into the lower
chamber of the hot section of the case and then through the desiccant
wheel to the upper chamber of the hot section of the case where
the second fan ejects the hot moist air to atmosphere.
The desiccant wheel rotates within the cabin and hot chambers of
the case to enable the desiccant material applied to the desiccant
wheel to first collect moisture in the cabin chamber and then releases
the moisture in the hot chamber. This is accomplished by the delivery
of the moist cabin air to half of the desiccant wheel by the first
fan where the moisture is adsorbed by the desiccant. As the dry
air exits the wheel it is directed back into the cabin. The desiccant
wheel slowly rotates into the hot chamber where the second fan pulls
in air from atmosphere across the heating elements of the heat exchanger
then the hot air enters the hot half of the desiccant wheel to evaporate
off the moisture that was previously adsorbed by the desiccant in
the cabin side of the apparatus. The hot chamber recharges (evaporates
the moisture) the desiccant wheel to prepare it for it's next cycle
through the cabin side of the apparatus. The now dry desiccant material
on this portion of the wheel rotates back into the cabin chamber
to continue the repetitive cycle.
To provide instant windshield defrost/defog action as soon as the
engine is started, an after shut down regeneration feature may also
be an element of the invention where the apparatus continues to
regenerate the desiccant material after engine shut down to completely
regenerate all or a portion of the desiccant material and then isolate
this material until the engine is restarted. The residual engine
heat would be transferred to the heat exchanger by the coolant fluid
and used to evaporate the moisture as the hot side fan forces hot
air through the desiccant to continue or start up the regeneration
process for the desiccant after engine shut down while the desiccant
wheel torque motor and the cabin side fan is off. When the regeneration
is complete or the residual engine heat is depleted the automatic
control unit deactivates all the fans and motors, and closes vent
doors or air valves to the regenerated desiccant to isolate the
desiccant material from any out side air that may contain moisture.
For the desiccant canister version of the apparatus the instant
action is provided in a similar manner where the air flow through
the evaporation side of the process continues to flow to regenerate
the desiccant material after engine shut down while the fan for
the adsorption side of the apparatus and the cross over valves are
deactivated the hot coolant fluid continues to transfer the residual
heat from the engine to perform the regeneration until the heat
is depleted or the regeneration is complete after which the evaporation
side fan motor is deactivated and the desiccant material is isolated
from any source of moisture when doors are closed on both ends of
the desiccant canister. The doors or air valves may either be separate
doors from the crossover valve or one of the close positions of
the crossover valve. When the vehicle is started the automatic control
unit may senses the need for dehumidification to defog/defrost the
inside of the windshield glass and there is a source of anhydrous
desiccant completely regenerated which can instantly perform the
dehumidification.
The invention may also include a cabin air baffle (valve) to direct
the dehumidified cabin air from the invention into the air-conditioning
system return air to reduce/eliminate the build up of frost on the
cooling coils in the air-conditioner. The baffle would only be activated
to direct air to the air-conditioner after the system sensors and
control system determined that the need to lower the humidity for
windshield defog/defrosting had been accomplished, the air-conditioner
was on, and the humidity level was high enough to warrant the need
for dehumidification to eliminate frost or improve the efficiency
of the unit.
The preferred fan arrangement is configured to provide positive
pressure on the cabin side and negative pressure on the hot side
of the case. The fan configuration will force any air leakage from
the cabin side to the hot side and the design further incorporates
seals to prevent air flow from the hot side to the cabin.
The optional sensors are included in this alternative of the invention
to provide information to the automatic electronic humidity control
unit. The sensors transmit data used by the control device for determining
when the windshield is approaching the dew point. This is accomplished
by the sensors providing both cabin air and windshield internal
and external temperature, and relative humidity information to the
control device. The electronic control device uses the sensor data
to determine when to turn on/off the apparatus and also displays
temperature and relative humidity information so the occupant(s)
may adjust the desired humidity to a lower level for comfort after
the system has eliminated the possibility of fog/frost on the windshield.
The invention also includes a method of removing condensation from
the interior cabin compartment of a motorized vehicle, which can
be summarized as including the following steps: monitoring the temperature
and humidity level of the cabin of a motorized vehicle, regulating
the humidity level of the cabin by electronically controlling the
apparatus to automatically turn the system on when condensation
could form on the windshield of the cabin, dehumidifying the air
extracted from the cabin by passing the air through rotating desiccant
material or desiccant canister during a dehumidification cycle,
recharging the desiccant with hot air then expelling the moist hot
air from the apparatus outside the system, introducing a dehumidified
air stream into the cabin compartment of a motor vehicle to lower
the relative humidity in the cabin to prevent/remove fog/frost on
the windows.
The desiccant canister type apparatus consisting of duel desiccant
canisters containing honeycomb coated with desiccant material and
connected to inflow and outflow crossover valves and work in conjunction
with heat exchangers which are controlled by the automatic control
unit to heat or cool the air stream. The automatic control unit
for the canister type apparatus either opens or closes the coolant
valves and/or activates the coolant pump to circulate the coolant
through the heat exchangers. The automatic control unit either utilizes
a timer to set the interval between cycles or sensors are utilized
to measure the evaporation and adsorption rate of the desiccant
within the canister to determine when to alternate the adsorption
and evaporation canisters so that as one canister becomes saturated
with moisture, it is replaced in the air stream by another canister
that has just completed an evaporation cycle.
The apparatus can be summarized in a variety of ways one of which
is the following: an automatic electronic humidity control device
to receive data from the temperature and humidity sensors and determines
if the relative humidity is approaching the dew point on the inside
of the windshield, the electronic humidity control device controls
the activation of the fans, motors, heat exchangers and valves to
start or stop the dehumidification process, a fan first passes cabin
air through a rotating desiccant wheel driven by a torque motor
to remove the moisture from the cabin air then forces the dehumidified
air back into the cabin, another fan pulls air from atmosphere to
be heated by the heat exchanger then the hot air is used to recharge
the desiccant material on the wheel as the wheel rotates into the
hot chamber, the hot moist air is then expelled back into the atmosphere
by the fan and the desiccant wheel continues it's rotation back
into the cabin side chamber of the case to perform another cycle
of dehumidification, the control device provides the occupants with
an adjustment option to set the desired relative humidity for the
unit so it will continue to lower the relative humidity below the
point where the automatic control would turn the system off.
For both the desiccant wheel and desiccant canister type apparatus
the dehumidified air stream passing through the anhydrous desiccant
is cool. As the dehydrated cool air stream exits the honeycomb desiccant
coated material the air may be passed through a heat exchanger to
increase the temperature of the air stream which will increase the
capacity of the air to defog/defrost the windshield glass.
The Automatic Digital Control Unit for land based vehicles consist
of three different types of control. The first, is a full feature
unit which automatically determines the desired settings for the
unit based on sensor readings of temperature and humidity both inside
and outside the vehicle. The occupant sets the unit on automatic
and the unit will continue to control the environmental system by
monitoring the outside air temperature and relative humidity and
based on these readings the control unit will automatically set
the preferred temperature, fan speed, and relative humidity.
Since the occupants are dressed with warmer clothing in the winter
and they are comfortable in a cooler temperature the automatic control
unit sets the thermostat mechanism lower than 72.degree. F. As the
temperature outside decreases the setting by the automatic controller
is lowered. When it is very cold the setting may be 67.degree. F.,
and as the outside air temperature increases the setting will be
automatically increased up to 72.degree. F. in cold weather.
The temperature settings are pre-established and make up an element
of the environmental profile which over may adjust the cabin air
temperature during the time of operation and may provide a higher
temperature when heat is first provided to warn the occupants when
they initially enter the vehicle and as the seats and occupants
warm up the automatic control unit begins to lower the temperature
to maintain perfect comfort without the occupant having to make
any environmental control adjustments. When the control unit is
set to the automatic feature the system is automatically activated
when the occupant starts the vehicle. The automatic control unit
will also maintain the relative humidity setting in the center of
the relative humidity zone of comfort as the temperature setting
is automatically adjusted by the unit. When the automatic control
unit senses that the relative humidity is outside of the desired
range the control unit will activate the dehumidification or humidification
even with the heating or cooling deactivated.
During warm or hot climate conditions such as summer the automatic
control unit senses the outside conditions an automatically adjust
the temperature cooling settings and the relative humidity settings.
Depending on the outside air temperature the control unit may set
the temperature in a range of 73.degree. F. to 79.degree. F. for
the cabin and also regulate the relative humidity as the control
unit regulates the air stream to the selected predetermined temperature
profile to control the apparatus as it cools down the occupants
with a lower temperature when they first start the vehicle and then
as the occupant's bodies are cooled the temperature is increased
along the temperature profile to a static level above the cool down
temperature.
The automatic control unit considers the readings of the outside
air temperature and relative humidity when it selects the desired
profile. The fan speed is also regulated by the automatic control
unit to provide a higher volume of air when increased heating or
cooling is determined to be necessary by the control unit where
there is a large difference in the desired and actual cabin temperature
or during the warm up or cool down phase of the profile. The automatic
profile feature of the control unit would determine the temperature
setting, relative humidity setting and fan speed for the system;
and then activate the functions of the apparatus to deliver the
desired conditions. The environmental profile established temperature
and fan speed profile may be adjusted by the occupants to replace
the factory established profiles.
If the occupants wish to return the settings to the factory profile
there is a reset button available to quickly reset these adjustments
to the factory settings. The second mode of the control unit is
a manual setting unit, where the occupant sets the desired temperature,
humidity, and air velocity and the automatic control unit controls
the operation of the apparatus to meet the desired settings established
by the occupant. The third, is a mode where the occupant turns the
system on or off and manually sets the unit to operate at either
high, medium, or low. A vehicle may have a control unit capable
of utilizing one or more of the three modes listed above with a
selector to allow the occupant to select which type is desired at
any given time. All of the preferred embodiments of the units have
an automatic defog, defrost feature where the windshield is automatically
defrosted when the sensors relay the temperature and relative humidity
information to the control and the control unit processor determines
that defrosting is necessary to prevent the formation of condensation
on the windshield and activates the apparatus to prevent or remove
the condensation.
For the benefit of explanation the previous descriptions have generally
been separated into either humidification or dehumidification descriptions.
Although the inventive apparatus can take the form of a single function
apparatus, the apparatus with the greatest benefit to the occupants
is one in which the automatic control unit regulates the combined
functions of humidification or dehumidification of the cabin air
and defrost/defog of the windshield glass are provided in a single
unit incorporating the environmental heating and cooling systems.
The apparatus is capable of total automation where the occupants
may never activate or adjust the environmental control system and
the apparatus delivers the highest level of environmental comfort.
The present invention describes a method and apparatus for adding
humidity to heated air for motorized vehicles utilizing a desiccant
based system. The humidification is accomplished without using water
as a spray (atomized) or dripping water on a mat material for evaporation.
The apparatus does not require the motorized vehicle to transport
a container of water since the moisture used for humidification
is extracted out of another air source.
Another alternative to humidification is described in this inventive
method and apparatus where humidity can also be removed from the
cabin air before the air returns to the cabin. The automatic control
unit automatically selects and activates the desired alternative
after it determines if humidification or dehumidification is needed.
In motorized vehicles, the defrost/defog, dehumidification and humidification
function may be performed while the motorized vehicle's environmental
system is using only recirculating air in the cabin and the cabin
heating and cooling may be deactivated during humidity conditioning.
Depending on the space available and the environmental system requirements
the configuration of desiccant honeycomb structure may vary between
two alternative methods of passing the air over the desiccant material:
1.) A desiccant wheel is used to perform waterless humidification
of heated air by adsorbing the humidity out of a cool air stream
after which the air is expelled into atmosphere, following the adsorption
cycle is the evaporation cycle where the moisture is released out
of the desiccant wheel into a heated air stream which will be used
to heat the cabin of a motorized vehicle.
The desiccant wheel slowly rotates through two separate chambers
as the moisture is transferred from one air stream to the other.
As the air passes through the first chamber where the cool air containing
varying amounts of humidity is adsorbed into the desiccant material
coated on the wheel. The desiccant wheel consist of a series of
small cylindrical air passage ways, or tubes of a variety of shapes
(hexagonal or round, or corrugated, honeycomb NOMEX etc.) either
coated with or consisting of material containing desiccant. As the
air passes through the cylindrical tubes, the moisture is adsorbed
out of the air stream into the desiccant material. The wheel slowly
rotates out of the first chamber into the second chamber. In the
second chamber the heat from the hot air passing through the wheel
causes the moisture in the desiccant material to evaporate into
the hot air stream.
In a variation to this embodiment, the first chamber, where the
moisture is adsorbed into the desiccant wheel may be divided into
two stages. With the two adsorption stage system, the air from which
the moisture is adsorbed may be provided from two separate sources.
In this configuration, the (dry) anhydrous desiccant wheel would
enter the first stage of the cool chamber through which the lowest
humidity air source is passing to adsorb the available moisture.
The wheel would then rotate toward the second stage source of cool
air with the highest available humidity. Then the desiccant wheel
would rotate into the hot air stream chamber where the moisture
previously adsorbed into the desiccant would evaporate into the
hot air stream. The evaporation of moisture that takes place in
the hot chamber would recharge the desiccant wheel to prepare the
wheel for the next adsorption cycle.
This process would repeat itself until the humidity reaches the
desired level. The automatic control unit would then turn off the
fans, torque motors, and close the valves to the heat exchangers.
This multi-stage alternative enables the system to extract moisture
from internal air before it is expelled outside, and also extract
moisture from an external air source that would also be expelled
outside. The automatic control unit sensors indicate the air mass
with the greatest moisture content and the automatic control unit
would then activate the wheel torque motor to rotate in the desired
direction. 2.) In the alternative, an adaptive canister containing
NOMEX honeycomb coated with desiccant (or other corrugated shaped
material coated with desiccant) may be positioned so as to allow
the air to flow through the small passages formed by the structure
of the honeycomb is used to perform the desired result of either
humidification or dehumidification of the air going to the cabin.
This method uses multiple canisters to sustain a constant air flow
by switching from one canister to another so as to allow the desiccant
filler to go through the adsorption cycle in one (or some) of the
canisters while another (or others) are going through the regenerative
cycle. The switching of the air into and out of the canisters is
accomplished by either a rotary valve or a series of electronically
controlled slide valves or gate valves.
The method of the present invention may be summarized in a variety
of ways, one of which is the following: a method of altering the
humidity level of a passenger cabin of a motorized vehicle having
a windshield with an interior surface, comprising the steps of:
providing a desiccant based moisture collection means or device
for collecting moisture from air; positioning the moisture collection
means or device in the path of an air stream; providing a heat source
capable of emitting heat sufficient to evaporate moisture from an
air stream; positioning the moisture collection means or device
in communication with the heat source; evaporating the moisture
removed by the moisture collection means or device into the atmosphere;
and directing the air stream from which the moisture was evaporated
into or out of the passenger cabin of a motorized vehicle.
Positioning the moisture collection means or device in the path
of an air stream may further include the step of: providing communication
with an air stream originating from a source external to the passenger
cabin; providing communication with an air stream originating from
a source internal to the passenger cabin; or, providing communication
with an air stream originating from a combination of sources including
at least one source internal to the passenger cabin and at least
one source external to the passenger cabin.
Directing the air stream from which the moisture was recovered
into the passenger cabin of a motorized vehicle may include: directing
the air stream at the interior surface of the windshield; directing
the air stream from which the moisture was recovered to an evaporator
for lowering the temperature of the air stream from which the moisture
was recovered enabling the evaporator to operate more efficiently;
directing the air stream to a pre-cooler prior to delivery to the
cabin.
The method may also include providing at least one heat exchanger
means for adjusting the temperature of an air stream; selectively
diverting the path of the air stream, in which moisture collection
means is positioned, away from the moisture collection means to
enable substantially complete evaporation of moisture by the heat
source from the moisture collection means; or, providing a system
of sensors capable of monitoring the environmental conditions to
which the cabin of a motorized vehicle is subject, and selectively
performing the steps associated with altering the humidity level.
The present invention may also be summarized as follows: a method
of altering the humidity level of a device having a holding compartment
subject to induced environmental conditions, the method comprising
the steps of providing a desiccant based moisture collection means
for collecting moisture from air; positioning the moisture collection
means in the path of an air stream; providing a heat source capable
of emitting heat sufficient to evaporate moisture from an air stream;
positioning the moisture collection means in communication with
the heat source; evaporating the moisture removed by the moisture
collection means into the atmosphere; and directing the air stream
from which the moisture was evaporated into the holding compartment.
The method may also include the step of providing a refrigerated
holding compartment.
An apparatus of the present invention may be summarized as follows:
an apparatus for regulating the humidity level of the cabin compartment
of a motorized vehicle having a windshield, the apparatus comprising:
dehumidification means for dehumidifying an air stream, wherein
the dehumidification means partially comprises a filler component
with a moisture absorbing desiccant substance applied to its surface,
and a canister having an interior, an inlet and an outlet; means
for drawing air from a source thereof and directing the drawn air
to the inlet of the canister enabling the dehumidification means
to extract moisture from drawn air; and a heat exchanger for extracting
heat from the motorized vehicle and delivering it to the interior
of the canister to dry the desiccant material after it has absorbed
moisture.
The heat exchanger may be configured to extract heat from the engine
compartment of the motorized vehicle. The apparatus may further
comprise a system of baffles positioned within the canister to direct
the flow of air through the dehumidification means, or an exhaust
means for expelling dry air from the canister through the outlet
of the housing. The filler may be a desiccant wheel, or have a system
of corrugations comprising a plurality of cells having a substantially
hexagonal perimeter and at least one divider for dividing the plurality
of cells into subcells for increasing the available surface area
and strength associated with each cell. The subcells may be filled
with a solid material. The desiccant wheel may include a center
drive means for operating the wheel.
It is an object of the present invention to provide an apparatus
for and a method of desiccant humidification of the cabin air of
a motorized vehicle to increase the relative humidity of the air
contained in the cabin. The desiccant adsorbs moisture out of the
stale cabin air before it is released from the cabin into the atmosphere
after which the moisture contained in the desiccant material is
then released into the fresh air stream to raise the relative humidity
of the fresh air before entering the cabin.
It is an object of the present invention to provide a desiccant
based apparatus which is capable of continuously humidifying a fresh
air stream from the atmosphere which is forced into the cabin of
a motorized vehicle. The apparatus adsorbs the moisture out of the
stale cabin air as the stale cabin air passes through a desiccant
material before the air exits the cabin into the atmosphere and
the moisture in the desiccant material is later released into the
fresh air stream entering the cabin through evaporation which increases
the relative humidity of the fresh air stream.
It is an object of the present invention to provide an apparatus
for and a method of environmental air conditioning where the air
stream is continuously humidity conditioned by a process where the
position of a desiccant material or the air stream which is entering
a desiccant material is altered or alternated to provide continuous
humidification or dehumidification of the intended air mass and
the heat energy of regeneration is provided from excess engine heat.
It is an object of the present invention to provide an apparatus
for and a method of desiccant humidification where the moisture
contained in stale cabin air is reclaimed out of the stale air and
reintroduced into the fresh air stream which then enters the cabin
of a motorized aircraft in order to increase the relative humidity
of the fresh air stream.
It is an object of the present invention to provide an apparatus
for and a method of air craft cabin environmental humidity air conditioning
through desiccant based humidification which reclaims moisture from
stale cabin air which is then evaporated into fresh outside air
entering the cabin to lower the level of carbon dioxide by increasing
the ratio of fresh outside air as compared to the ratio of stale
cabin air without lowering the cabin relative humidity below the
human comfort level of 35% R.H.
It is an object of the present invention to provide an apparatus
for and a method of desiccant relative humidity control air conditioning
for the cabin air of a motorized vehicle where the excess vehicle
engine heat or the heat created from the act of compressing the
fresh air going to the cabin as it passes through or over the surface
of the desiccant material cause the moisture in the desiccant to
evaporate into the air stream.
It is an object of the present invention to provide an apparatus
contained within a non pressurized aircraft cabin compartment or
within any other area of the aircraft where two different air streams
each passed through separate sections of a single or multiple rotating
desiccant wheel to accomplish the adsorption and evaporation of
moisture into and out of the desiccant material for cabin humidification.
Where the source of moisture is cold fresh outside air passing through
one side of the desiccant wheel and returning to the atmosphere,
after which hot air performs the evaporation of the moisture out
of the desiccant material into the air entering the cabin.
It is an object of the present invention to provide an apparatus
contained within the cabin compartment of a motorized vehicle or
any other area of the vehicle where two different air streams each
passed through separate sections of a single or multiple rotating
desiccant wheel to accomplish the adsorption and evaporation of
moisture into and out of the desiccant material for cabin humidification.
Where the source of moisture is cool stale air from the cabin passing
through one side of the desiccant wheel and expelled into the atmosphere,
after which hot air performs the evaporation of the moisture out
of the desiccant material into the air entering the cabin.
It is an object of the present invention to provide an apparatus
contained within the cabin compartment of a motorized vehicle or
any other area of the vehicle where three different air streams
each passed through separate sections of a single or multiple rotating
desiccant wheel to accomplish the adsorption and evaporation of
moisture into and out of the desiccant material for cabin humidification.
Where the source of moisture is both cool stale cabin air and cold
outside air passing through one side of the desiccant wheel and
expelled into the atmosphere, after which hot air performs the evaporation
of the moisture out of the desiccant material into the air entering
the cabin.
It is an object of the present invention to provide an apparatus
where the air flow and desiccant wheel rotation are controlled by
an automatic control unit which monitors the process through temperature
and relative humidity sensors and then activates the motors and
valves to regulate the level of relative humidity within the cabin.
It is an object of the present invention to provide a process where
the adsorption and evaporation of moisture into and out of a desiccant
material for the purpose of raising the relative humidity of the
cabin air is accomplished with excess heat present in the compressed
air entering the cabin.
It is yet another object of the present invention to provide an
apparatus where the expansion of the cabin air of a pressurized
cabin as it escapes to atmosphere provides the cooling for a heat
exchanger when the air passes through a regulator valve into an
expansion chamber with a lower air pressure. The expansion chamber
is vented to atmosphere through a regulator valve which allows the
stale cabin air to escape into atmosphere. The cooling provided
by the heat exchanger/expansion chamber serves to cool the stale
air before it passes through the desiccant material during the adsorption
phase and also cools the hot compressed air from the engine used
to evaporate the moisture after the hot air passes through the desiccant
during the evaporation phase to regulate the cabin temperature.
It is a further object of the present invention to provide a process
of automatically regulating the relative humidity of the cabin air
of a motorized vehicle through the use of a desiccant apparatus;
automatically eliminating frost, fog or condensation on the surface
of the windshield glass of a motorized vehicle; automatically preventing
the formation of condensation, fog or frost on the surface of the
windshield glass of a motorized vehicle.
It is a further object of the present invention to provide a process
of automatically regulating the relative humidity of the cabin air
of a motorized vehicle through the use of a desiccant apparatus.
Where an Automatic Control Unit (ACU) consisting of temperature
and relative humidity sensors, a display unit with display features
and occupant control selection switches, an electronic control processor
and electrical output switches to activate, deactivate and regulate
the other components of the inventive apparatus. Although the capability
of the ACU may vary from regulating one element of the relative
humidity to a complete environmental control unit, the desiccant
invention must have a control method to produce the desired results.
It is a further object of the present invention to provide a process
of automatically eliminating frost, fog or condensation on the surface
of the windshield glass of a motorized vehicle through the use of
desiccants where the Automatic Control Unit (ACU) monitors a set
of sensors to automatically detects the formation of fog, frost,
or other condensation on the inside surface of the windshield glass
and then automatically activates the components of the inventive
apparatus to eliminates the condensation which may have formed on
the inside of the windshield glass.
It is a further object of the present invention to provide a process
of automatically preventing the formation of condensation, fog or
frost on the surface of the windshield glass of a motorized vehicle
through the use of desiccants where the Automatic Control Unit (ACU)
monitors a set of sensors to detect the environmental conditions
which may approach a point which could cause fog, frost or other
condensation to form on the inside of the windshield glass. The
ACU automatically activates the components of the inventive apparatus
prior to the formation of any condensation to assure the occupants
of the motorized vehicle never have their visibility impaired by
the formation of condensation while the vehicle is in operation.
It is a further object of the present invention to provide an inventive
apparatus which may utilize a center drive desiccant wheel consisting
of a honeycomb NOMEX wheel which has a (metal &/or plastic)
center spline drive to support the desiccant wheel and provide the
transfer of torque from the torque motor to the wheel. A reduction
gear box may provide the necessary RPM reduction from the motor
to the slowly rotating desiccant wheel. A metal &/or plastic
band may encase the perimeter of the wheel and attached to the wheel
by a permanent bond with an adhesive to provide structural support
and prevent abrasion of the NOMEX honeycomb where the wheel contacts
the seals or case during rotation.
It is a further object of the present invention to provide an inventive
apparatus which may utilize an adaptive desiccant canister case
in place of the desiccant wheel, where the air flow through a set
of desiccant canisters is alternated between the individual canisters
to provide a continuous adsorption and evaporation process.
It is a further object of the present invention to provide an inventive
apparatus which may have a set of vent doors (air valves) which
may be utilized to configure the air flow through the apparatus
in such a way as to allow the apparatus to continue to regenerate
the desiccant material after the motor is shut down by utilizing
the residual heat from the motor and then when regeneration is complete
the vent doors are configured to isolate the desiccant from air
exterior to the apparatus. The storage of regenerated desiccant
allows the apparatus to deliver an instant dehumidified air stream
immediately after the next engine start up. Dehumidified air may
be delivered by the apparatus before the motor has heated up to
a temperature capable of providing the necessary heat for evaporation.
It is a further object of the present invention to provide an inventive
method and apparatus capable of delivering a humidified air stream
to the cabin or a dehumidified air stream to the cabin; and/or a
defog/defrost dehumidified ambient or heated air stream to the windshield
from a recirculated air source originating from the cabin. The invention
is unique due to it's ability to deliver humidification, dehumidification,
and/or defog by using recirculated cabin air which allows the occupants
to avoid the need to introduce smoke or other noxious gases into
the vehicle from the exterior of the vehicle while conditioning
the air in the event that the vehicle is passing through an undesirable
air mass.
These and other objects, advantages and features of the present
invention shall become apparent after consideration of the specification
and drawings set forth herein, and all such objects, advantages
and features are contemplated within the scope of the present invention
whose only limitation is the scope of the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side view of an embodiment of the apparatus
of the present invention in an automobile application;
FIG. 2 is a schematic top view showing the rotation of the desiccant
wheel of the apparatus of FIG. 1;
FIG. 3 is a schematic side view, with arrows to show the air flow
direction, of the overall system of FIG. 1 including components
of a representative motorized vehicle;
FIG. 4 is an enlarged schematic side view of some of the components
shown in FIG. 3 with arrows showing air flow and hot water(coolant)
flow direction, and electrical wiring;
FIG. 5 is an enlarged schematic of the apparatus case and components
shown in FIG. 4;
FIG. 6 is a detailed side view of the torque drive system and the
seal component, dividing the cabin and hot chamber shown in FIG.
5;
FIG. 7 is a perspective view of the apparatus of FIG. 4;
FIG. 8A is a perspective view of the lower case and components
of the apparatus of FIG. 7 with the top cover and desiccant wheel
removed therefrom;
FIG. 8B is a partial cross-section of the hot chamber side of the
case portion of the apparatus shown in FIG. 7;
FIG. 9A is a perspective of the embodiment of the desiccant wheel
of the present invention;
FIG. 9B is a front view of an alternate embodiment of the desiccant
wheel shown in FIG. 9A;
FIG. 10 is a partially fragmented perspective view of a portion
of the wheel shown in FIG. 9A;
FIG. 11 is a schematic view of the air flow pattern of the invention
shown in use in a helicopter embodiment of the system;
FIGS. 12 and 13 are detailed schematic views of the invention shown
in FIG. 11;
FIG. 14 is a summary chart listing sources of moisture, sources
of heat, and a summarized list of the inventive methods.
FIG. 15 is a method flow chart showing how fresh outside air is
heated and humidified to increase the relative humidity of the cabin
air.
FIG. 16 is a method flow chart showing how recirculated cabin air
is heated and humidified to increase the relative humidity of the
cabin air.
FIG. 17 is a method flow chart showing how recirculated cabin air
is dehumidified to lower the relative humidity of the cabin air.
FIG. 18 is a method flow chart showing how fresh outside air is
dehumidified to lower the relative humidity of the fresh air going
into the cabin.
FIG. 19 is a method flow chart showing how the relative humidity
of the cabin recirculated air is lowered before the dehumidified
air goes through the air-conditioner evaporator cooling unit thus
increasing the efficiency of the air-conditioner.
FIG. 20 is a method flow chart showing how the relative humidity
of fresh air going into the cabin is lowered before the air goes
through the air-conditioner evaporator cooling unit to increase
the efficiency of the air-conditioner.
FIG. 21 is a method flow chart showing how recirculated cabin is
dehumidified and then used to defog/defrost the inside surface of
the windshield.
FIG. 22 is a method flow chart showing how fresh outside air is
dehumidified and then used to defog/defrost the inside surface of
the windshield.
FIG. 23 is a summary chart showing the general functions and benefits
of the inventive method.
FIG. 24 is a diagram showing the desiccant process of humidification
of a fresh air stream going into an aircraft cabin from the engine
compressor to increase the relative humidity of the cabin.
FIG. 25 is a diagram showing the source of moisture and the air
flow for the desiccant humidification of an aircraft cabin.
FIG. 26 is a concept drawing showing a desiccant based aircraft
cabin humidification system utilizing a desiccant wheel where the
source of moisture is the outside air.
FIG. 27 is a concept drawing showing a desiccant based aircraft
cabin humidification system utilizing a desiccant wheel where the
source of moisture is the stale cabin air before it is expelled
from the aircraft.
FIG. 28 is a concept drawing showing a desiccant based aircraft
cabin humidification system utilizing a desiccant wheel where there
is a duel source of moisture.
FIG. 29 is a drawing showing a desiccant based aircraft cabin humidification
system utilizing a desiccant wheel.
FIG. 30 is a schematic showing a desiccant wheel aircraft cabin
humidification system.
FIG. 31 is a schematic showing a desiccant based aircraft cabin
humidification system utilizing a desiccant wheel including a cooling
unit to lower the air temperature of both the fresh air after it
is humidified and also the old stale air before the moisture is
adsorbed into the desiccant wheel.
FIG. 32 is a schematic showing a desiccant based aircraft cabin
humidification system utilizing a desiccant wheel including a cooling
unit to lower the air temperature of the fresh air after it is humidified.
The stale cabin air is not cooled before it passes through the desiccant
wheel.
FIG. 33 is a diagram showing the adsorption of moisture by a desiccant
canister from stale cabin air before the air is released into the
atmosphere.
FIG. 34 is a schematic drawing showing a duel alternating desiccant
canister process where one canister is in the adsorption cycle while
the other is in the evaporation (regeneration) cycle.
FIG. 35 is a schematic drawing showing a duel alternating desiccant
canister process where one canister is in the adsorption cycle while
the other is in the evaporation cycle included is the crossover
valve and the fresh air cooling unit.
FIG. 36 is a block diagram of an aircraft canister desiccant process
where a single crossover valve is utilized to alternate the air
flow both into and out of the canisters.
FIG. 37 is a block diagram showing the airflow through the rotary
crossover valve.
FIG. 38 is a cutaway drawing of a desiccant canister.
FIG. 39 is a cutaway drawing of a desiccant canister showing how
the canister can be adapted to various shape and size requirements.
FIG. 40 is a cutaway drawing top view of the air flow, baffles,
and honeycomb orientation in a desiccant canister.
FIG. 41A is a cut away of a desiccant canister which also serves
as a crash adsorption panel with a center input and out flow opening.
FIG. 41B is a cut away of a desicc |