A VEHICULAR CABIN COOLING SYSTEM
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicular cabin cooling system. In particular, the
present invention relates to an evaporative cooling system for passenger and pilot
cabins of a vehicle.
BACKGROUND ART
Cooling systems are quite common in offices and various types of dwelling units.
Cooling systems are of various types. The preferred cooling system now-a-days is
what is commonly called as 'air conditioning systems'. In such systems the liquid
used for heat transfer is not lost in the process as it is cyclically evaporated and
condensed using a compressor. For evaporation this liquid takes heat energy from
the environment and due to loss of heat, the temperature is reduced. Due to
absorption of heat, this liquid changes its state to gas. The gaseous form of the heat
transfer medium is again converted to its liquid form for re-circulation by a
compressor that requires an additional source of energy. Such systems are effective
but, they consume lot of energy and are thus, not economical. Moreover, these
systems are very heavy also. Due to their dependence on large amount of external
energy, such as electric energy, air conditioning does not prove to be economical
especially for the commercial vehicles in India.
Another system of cooling is through water-evaporation. In these systems air is
laden with water vapor and provides a sense of cooling. The temperature of air is
also brought down by evaporation of water in the evaporation bed. In these systems,
the heat transfer medium i.e. water is not re-circulated but, lost to the environment
in vapor form.
The rate of cooling in water evaporative systems depends on the surface area of the
evaporative bed that comes in contact with the air. It also depends on the duration
of the contact of air with the evaporative bed so as to effectively achieve proper
heat transfer. In vehicular systems, particularly when the vehicle is moving at a fast
speed, the air flows at a very high speed resulting in poor contact with the
evaporative bed. Moreover, since the air is sucked in large quantities and at high
speed, the hotter air mixes up with the cooler air coming out of the evaporative bed
due to spillage as such systems are not provided with proper compartments for inlet
and outlet of air.
Apart from lack of effective cooling, the cooling systems of the prior art are bulky
and inconvenient to be placed on the top of cabins in vehicles.
SUMMARY OF THE INVENTION
The present invention provides a vehicular cooling system such that the velocity of
the inlet air is reduced while it comes in contact with the evaporating bed and the
surface area of the contact is also increased to provide effective cooling.
Simultaneously, the pressure at the outlet side of the evaporative bed is lowered so
that the water in the bed turns into vapor (due to lower vapor pressure) and such
vapor is also dragged by the air flowing out from the evaporating bed. The overall
result is increase in cooling as compared to the evaporative cooling of the prior art.
According to one embodiment a Vehicular Cooling System is provided for cooling
at least one cabin in a vehicle comprising: at least one air inlet; a passage for
directing air to upstream side of an evaporative bed and prevent spilling of inlet air
with the outlet air; an impeller to pull the cool air from downstream side of the
evaporative bed; and
at least one water conduit for drenching the evaporative bed, wherein, a barrier
slows down the inlet air and directs it to the upstream side of an evaporative bed.
According to another embodiment of the present invention the barrier protrudes
downwards from a top cover.
According to yet another embodiment of the present invention the air inlet is
provided on the upper surface of the top cover andlor the air inlet comprises orifices
for inlet of air, cut on an inclined surface to face the air flowing over the top cover.
According to one other embodiment of the present invention, the orifices Wher
comprise of at least one filter for filtering the inlet air.
According to yet another embodiment of the present invention, the at least one
water conduit is connected to a water reservoir through electro-mechanical means
and has at least one water conduit has at least one orifice to eject water onto the
evaporative bed.
According to an embodiment of the present invention the evaporative bed is made
up of polyurethane, reticulated polyurethane, polyurethane reinforced with Sodium
Acrylate, cellulose, honeycomb any other hydrophilic and water absorbent material.
According to another embodiment of the present invention, the impeller vaporizes
water present in the downstream side of the evaporative bed, pulls the air from the
upstream side of the evaporative bed and throws the cool air into at least one
vehicle cabin.
BRIEF DESCRIPTION OF THE DRAWINGS:
Figure 1 illustrates one preferred embodiment of the present invention.
Figure 2 illustrates a top cover of the vehicular cooling system according to one
embodiment of the present invention.
Figure 3 illustrates a drenching sub-system of the vehicular cooling system
according to one embodiment.
Figure 4 illustrates an embodiment of a water conduit of a vehicular cooling system
of the present invention.
Figure 5 illustrates a rolled evaporative bed according to an embodiment of the
present invention.
DETAILED DESCRIPTION OF THE DRAWINGS:
The present invention has been described herein through embodiments that fully
and particularly describe the invention along with its operation. The embodiments
of the present invention that would follow hereinafter disclose the best way of
performing the invention. The components of the present invention have been
explained with the help of illustrations and details that are sufficient to understand
the best way of performing, not necessarily including the details that will be
apparent to those ordinarily skilled in the art. It would also be apparent to any
person skilled in the art that the embodiments presented hereinafter are not limiting
embodiments and the present invention can be performed through other
embodiments carrying the same pith and substance as that of the best mode.
Figure 1 illustrates one embodiment of the vehicular cooling system (100). The
vehicular cooling system (100) comprises at least one air inlet (101) connected to
an upstream chamber(l02). In a moving vehicle, the air hits the inlet cover of the
present invention at a very high speed but, due to orientation of the inlet, the air
loses most of its speed as explained later.
The inlet air is at a very high speed and while entering the flowing air hits a barrier
(103) when it loses most of its kinetic energy. Apart from that, the barrier (103) is
shaped such that the inlet air is directed to the inflow side (104) of an evaporative
bed (1 05). The inlet air fills the upstream chamber (I 02).
The evaporative bed (105) is a wet bed comprising of a hydrophilic and water
absorbent material to retain water within itself. The water spreads onto the whole
surface of the absorbent material due to direct drenching or through capillary
action. The absorbent material is provided with sufficient water to keep it fully
drenched.
The inlet slow air enters the evaporative bed (105) and comes in contact with the
water trapped in the absorbent material. The absorbent material used as the
evaporative bed serves dual purpose and thus, the material is chosen such that both
the purposes are achieved. One purpose is to retain large amount of water within
itself. The other purpose is to provide small pores so that the air could easily flow
through it. The inflow air flows through the pores of the absorbent material and it
also picks up vapor from the surface of the evaporative bed. The material at the top
surface is soon replenished with water from the lower surfaces through capillary
action or through direct drenching. Thus, for effective replenishment, this material
should also show quicker capillary action.
The absorbent material used in the present invention according to one embodiment
is reticulated polyurethane. Polyurethane beds act as good water absorbents.
However, the top surface has a very high surface tension that makes their surface
hydrophobic. Thus, though polyurethane is a good absorbent, their hydrophobic
surface prevents drenching of beds and the water is not absorbed effectively.
Accordingly, the present invention uses reticulated polyurethane which is both
hydrophilic at surface and good absorbent. In another suitable embodiment, the
evaporative bed (105) is made up of polyurethane reinforced with Sodium Acrylate.
One of the most important advantage of using polyurethane is that it does not
deteriorate in water and requires least maintenance thus, making it affordable for
the drivers and owners of the commercial vehicles in India.
Another absorbent material that may be used in the present invention is cellulose.
For example, absorbent materials made up of cardboard such as honey-comb beds,
wood shavings and dried grass may also form the evaporative bed (105) according
to another embodiment of the present invention.
The flowing air gets laden with vapor and also loses heat while evaporating the
water from the evaporative bed (105). However, the air flow does not have
sufficient speed to reach the cabin of the vehicle automatically.
In order to enable the cool air to reach the cabin, an impeller (106) is provided
downstream to the evaporative bed (105). The impeller creates a vacuum in the
downstream chamber (107) as it sucks air from said chamber. Due to sucking of air
by the impeller(l06), the vapor pressure decreases downstream the evaporative bed
(105). This causes the water retained in the absorbent material to vaporize.
Meanwhile, due to decrease in pressure, the air from upstream chamber (1 02) flows
to the downstream chamber (107). At the downstream chamber (107), the already
cool air also picks up the water vaporized in said chamber (107) due to decrease in
vapor pressure. As the air moves from the upstream chamber (102) it slowly gains
kinetic energy. This cool air is then directed via vents into the vehicular cabin.
Figure 2 illustrates a top cover (200) of the vehicular cooling system according to
one embodiment of the present invention. The outer cover may be made up of
metal, alloy or any non-metallic materials such as fiber, plastics, wood etc. The top
surface of the cover is polished and plane so as to reduce friction while air is
flowing over it. The cover is designed in an aerodynamic manner such that it does
not interfere with the aerodynamic design of the vehicle. In other words, the outer
cover is polished and designed to minimize drag.
At least one inlet for air is provided on the top cover according to one embodiment
of the present invention. A person skilled in the art would easily reckon that the air
inlets can be provided anywhere on the cover. The air inlets comprise of big orifices
(201) cut into the cover to provide a passage for the travelling air.
In order to prevent dust and other foreign bodies from entering the cooling system,
the orifices (201) are fitted with detachable filters to restrain dust and other
unwanted particles from entering the system. The filters are detachable and can be
cleaned manually by removing them from the air inlets. At the places where orifices
are cut into the cover, the top surface of the cover is elevated to provide an inclined
barrier to the passing air. Due to said inclination, the orifices face the rushing air in
an inclined manner so that air enters the orifices to reach the evaporative bed (not
shown).
The top cover (200) has a barrier (202) protruding from its inner surface. The
barrier is shaped in such a way that the air entering the orifices hit it and gets
deflected towards the evaporative bed below. It also reduces the kinetic energy of
the inflowing air so that longer contact time becomes possible between the air and
the evaporative bed. The top cover also has a passage through which the inlet air
reaches the upstream side of the evaporative bed without spilling into the
downstream side.
The lower cover (200L) rests on the roof of the vehicle either directly or through
harnesses such as those already known to a person skilled in the art. The inner
surface of the lower cover (200L) also comprises a barrier (203) laterally displaced
from the barrier of the top cover (200) so as to provide a longer path for the air
travelling downstream from the evaporative bed. Since the area decreases at the
barrier, it further increases the velocity of air that is being pulled by the impeller.
The lower cover may be of the same material as that of the top cover or a totally
different material.
Figure 3 illustrates a drenching sub-system (300) of the vehicular cooling system
according to one embodiment. The drenching sub-system (300) broadly comprises a
mechanism for delivering water under pressure from the water reservoir to the
conduits to throw the water evenly over the evaporative bed.
The drenching sub-system (300) comprises a water reservoir (301) located under
the evaporative bed in order to save space. The water reservoir (301) is formed by
having forming a water tank in the lower cover of the vehicular cooling system.
According to an embodiment, the lower cover has a barrier and a tank wall to form
the water tank. The evaporative bed (302) is placed on a platform connected to
barrier and the posterior wall of the lower cover.
The water from the water reservoir (301) is transported to at least one water conduit
(303) by electro-mechanical means (304). The electro-mechanical means (304) also
ensure that the water is transported to the water conduit (303) under pressure so as
to spread the water evenly on the evaporative bed (302).
In another embodiment, a water reservoir is located separately at the bottom of the
vehicle or some other place on the vehicle. The water from the water reservoir in
that case is transported by means of electro-mechanical means as well. The electromechanical
means include electric pumps, hydraulic pumps or even purely
mechanical pumps connected to moving parts of the vehicle. The electromechanical
means are already known to the person skilled in the art and one
mechanism makes no different from the other.
Figure 4 illustrates an embodiment of a water conduit (400) of a vehicular cooling
system of the present invention. The water conduit (400) comprises at least one
hollow pipe (401) running over the evaporative bed (402). The at least one hollow
pipe (401) further comprises of at least one orifice (403) through which the water
from the water reservoir (not shown) is spread over the evaporative bed underneath
(402).
In this embodiment, multiple orifices (403) are shown on the water conduit (400) in
an alternate arrangement. Since the water conduit (400) is running over center line
of the evaporative bed (402), orifices (403) are required on both sides of the water
conduit (400) so as to cover the whole surface of the evaporative bed (402) with
water.
In another embodiment, the water conduit (400) may comprise of nozzles for
spraying the water evenly on the evaporative bed. The water may also be spread as
a mist to increase cooling. A person skilled in the art would concur that the water
may be sprayed over the evaporative bed (402) through several other means known
in the prior art.
Figure 5 illustrates a rolled evaporative bed (500) according to an embodiment of
the present invention. The evaporative bed (500) is made up of a polyurethane
sheet, which is rolled to form a cylinder. The water is sprayed on the cylindrical bed
(500) from the water conduit running on top of it. There may be more than one
water conduits to soak the evaporative bed effectively from all sides.
A passage is provided in the top cover of the vehicular cooling system to direct the
inlet air into an anterior end (501) of the cylindrical bed (500). The air passes
through the hollow portion on the inside of the bed and picks up vapor while
transiting through it. The inner surface of the bed may also have tiny protrusions to
increase the surface area of contact and to slow down the air flowing through it. In
addition to that, an impeller is provided on the posterior end (502) of the cylindrical
bed (500) to pull the air travelling through the cylindrical bed (500).
An impeller in all of the above embodiments may be any electro-mechanical device
to pull a medium from one side and throw the same on the other side with more
pressure or speed.
The cylindrical shape of the evaporative bed and transit of air through it ensures
that the hot air is not leaked and all the air comes into contact with the wet surface
of the bed before exiting. This way a more effective cooling is achieved.
While the preferred embodiments of the invention have been illustrated and
described, it will be clear that the invention is not limited to these embodiments
only. Numerous modifications, changes, variations, substitutions and equivalents
will be apparent to those skilled in the art, without departing from the spirit and
scope of the invention, as described in the claims.

We claim:
1. A Vehicular Cooling System for cooling at least one cabin in a vehicle
comprising:
at least one air inlet;
a passage for directing air to upstream side of an evaporative bed and prevent
spilling of inlet air into the outlet air;
an impeller to pull the cool air from downstream side of the evaporative bed;
and
at least one water conduit for drenching the evaporative bed,
wherein,
a barrier slows down the inlet air and directs it to the upstream side of the
evaporative bed.
2. The system as claimed in claims 1&2, wherein the barrier protrudes downwards
from a top cover.
3. The system as claimed in claim 1, wherein the air inlet is provided on the upper
surface of the top cover.
4. The system as claimed in any of the preceding claims, wherein the air inlet
comprises orifices for inlet of air, cut on an inclined surface to face the air
flowing over the top cover.
5. The system as claimed in claim 4, wherein the orifices further comprise of at
least one filter for filtering the inlet air.
6. The system as claimed in claim 1, wherein the at least one water conduit is
connected to a water reservoir.
7. The system as claimed in claim 6, wherein the at least one water conduit is
connected to a water reservoir through electro-mechanical means.
8. The system as claimed in claims 6 and 7, wherein the at least one water conduit
has at least one orifice to eject water onto the evaporative bed.
9. The system as claimed in any of the preceding claims, wherein the evaporative
bed is made up of polyurethane, reticulated polyurethane, polyurethane
reinforced with Sodium Acrylate, cellulose, honeycomb any other hydrophilic
and water absorbent material.
10. The system as claimed in claim 1, wherein the impeller vaporizes water present
in the downstream side of the evaporative bed, pulls the air from the upstream
side of the evaporative bed and throws the cool air into at least one vehicle
cabin.