DESC:FIELD OF THE INVENTION
[001] The present invention relates to air cooling system and method of manufacturing thereof. The air-cooling system of present invention reduces the atmospheric air temperature and humidity like conventional automotive air conditioners but at lower power consumption rate from vehicle’s engine. The conventional air conditioner generally works on recirculation of air hence CO2 concentration inside cabin is increased over time, while air cooling system of present invention works better in fresh environmental air.
[002] The air-cooling system comprises of refrigerant-water heat exchanger in addition to parts used in conventional air conditioner. However the air cooling system of present subject matter comprises a blower fixed in center of unit, pulling supply air through condenser, increasing moisture carrying capacity, then through cooling pad reducing air temperature by water evaporation and thereafter pushing through refrigerant-air heat exchanger for humidity reduction. The cooled water approx. 7 °C is circulated on cooling pads for cooling of supply air.
[003] Here the refrigerant-water heat exchanger of the present subject matter is a unique configuration of refrigerant-water heat exchanger in a very specific manner provides continuous supply of low temperature water of approx. 7 °C for air cooling. The refrigerant-air heat exchanger packaged such that it reduces humidity of supply air coming from cooling pad & condenser packaged such that it increases temperature of air by 3 to 5 °C and increases air cooling capacity even in very high humid environment condition, where normal and conventional air conditioner get failed to operate properly.
BACKGROUND
[004] Vehicle cabins such as truck cabins are made to occupy at least two people i.e., a driver and a co-driver and their belongings depending on the applications for which the vehicles are used. Since the trucks are also used on long hauls and in varying atmospheric conditions ranging from hot and humid to cold and dry, the comfort of the occupants is taken care by installing an air conditioner unit or an air-cooling system in the cabin of the vehicle. The conventional air conditioner system comprises a blower, a compressor, a condenser, a pump and an evaporator at the last and drives power either from the engine or from an external power source such as an electrical battery. This system thus puts an extra cost on the truck manufacturer and consequently on the customer. In other cases where the air conditioner is not used, ventilation is brought about by blowing air into the cabin using an air cooler system. But this alternative also incurs poor performance and high humidity lead to uncomfortable situation to occupants.
[005] Further commercial vehicles running in India are exposed to very hot and humid ambient conditions. In truck cabin the comfort of the occupants is taken care by installing conventional vapor compression-based air conditioner units. However, the conventional air conditioner in truck cabin provides thermal comfort by consuming very high power approx. 3 kW engine power.
[006] In India and most of the other developing countries, manufacturers provide majority of the cabins without an air conditioning system, because of fuel economy penalty, as air conditioner draws very high engine power, and the blower unit alone is unable to cater to the cabin occupants’ comfort.
[007] Alternative of conventional air conditioner is water based evaporative air-cooling system, but temperature drop from evaporative air cooler is too less, approx. 5-7°C with respect to ambient temperature hence this air cooler is being used as parking cooler only instead of complete alternative of conventional air conditioner. Therefore, occupants’ comfort is hence largely neglected.
[008] The air-cooling method for automobiles described in US Patent Number 20170203632A1 pertain to a parking cooler having battery-powered air conditioning using a variable speed compressor which varies operating conditions based on comparisons between temperature set point and actual temperature in a cabin.
[009] Further US Pat. 4835982A relates to a mobile cooling apparatus that provides a large volume of previously cooled air containing a suspended mist for cooling objects and air in an unenclosed space and the US Pat. 10336160B2 pertains to a vehicular cooling unit using gas porous evaporative cooling media, preferably bactericidal wood shavings to provide cooled air into truck cabin.
[0010] U S Pat No. 8490422 B2 describes an evaporative air cooler with multistage cooling or having with or without cooling coil. The U S Pat No. 20130081414 A1 describes an evaporative cooler that includes a frame, a plurality of pads attached to the frame so that the pads substantially enclose an air space to be cooled, a water delivery device positioned at or near the top of the pads to wet the pads a plurality of drain pans positioned at or near the bottom of the pads to collect water from the pads and a fan to draw air through the wetted pads, thereby cooling the air by evaporation.
[0011] Therefore, to provide a thermal comfort to the occupants in truck cabin, a conventional vapor compression-based air conditioner and an evaporative air-cooling system are widely used across the globe. But both of the climate control systems have many limitations.
[0012] Conventional air conditioner performs well in terms of higher temperature drops with respect to ambient temperature, but it has following limitations:
1. Consumes up to 5% of engine power, depending on the application, resulting in poor fuel economy of vehicle with running air conditioner.
2. Generally, it operates in air recirculation mode hence creating higher CO2 concentration inside cabin over the time and creating ill impact on occupant’s health & attentiveness in the long run.
3. Reducing relative humidity level of supply air to less than 30% resulting in ill impact on occupants’ respiratory system.
4. Higher pollution emission because of higher fuel penalty.

[0013] Conventional evaporative air cooler system has approx. 90% lesser power consumption and provides continuous fresh air supply with respect to conventional air conditioner, but it has following major limitations.
1. Poor performance, lesser temperature drops of approx. 5-7 °C with respect to ambient temperature.
2. Very poor performance of approx. 2-3 °C with respect to ambient in high humid conditions because of less moisture carrying capacity of supply air.
3. Poor comfort level in cabin due to increase in relative humidity to more than 60% in an enclosed environment.
[0014] Hence there is an unmet need of a low cost, energy efficient air conditioning system, which could solve the aforementioned and other allied problems and meet the minimum comfort requirement of the occupants, without acting as a parasite on the engine and its fuel efficiency.
BRIEF DESCRIPTION
[0015] The present invention relates to relates to air cooling system and method of manufacturing thereof. The air-cooling system of present invention is an integration of conventional air condition with a refrigerant-water heat exchanger in such a manner to provide cost-effective user-friendly air conditioner system operates at optimal temperature and consume less electricity as compared to conventional air-cooling system. Further the illustration of present invention can be demonstrated in a fashion to avoid further limitations pertaining to conventional air-cooling system.
[0016] The air-cooling system of present invention consumes approx. 65% lesser power from engines as it uses only 0.8kW-1kW compressor for reducing temperature of water for cooling pads instead of using it to reduce temperature of supply air, up to desired in-cab temperature. Further it operates in fresh air mode hence not creating higher CO2 concentration inside cabin over the time and increasing attentiveness and improved health of occupants.

[0017] In one embodiment, the air-cooling system of present invention optimize the humidity level less than 30% as secondary evaporator (refrigerant-air secondary heat exchanger) works on approx. 10-12 °C instead of conventional 4-6 °C hence it is not creating ill impact on occupant’s respiratory system. Further the power consumption is about 75% lesser than conventional vapor compression air conditioner hence it creates lesser pollution emission because of lesser fuel penalty.

[0018] In the air-cooling system of present invention, the supply air is first passed through air cooling pads, where supply air temperature is reduced by 14-15 °C by cooling of supply air with approx. 7 °C chilled water and evaporating effect in cooling pad, then further temperature reduction of approx. 6-7 °C happens due to sensible heat transfer with chilled water & also in secondary refrigerant-air heat exchanger. The supply air temperature of air at cabin inlet is approximately 23 °C which is 2 to 3 times better than conventional evaporative air-cooling system and approx. at par with conventional air conditioner in higher ambient condition greater than 45 °C. Therefore, the air-cooling system of present invention works better than conventional air-cooling system in high humid conditions as well - supply air is first passed through condenser, increasing its temperature by 2-3 °C compared to ambient, thereby increasing its moisture carrying capacity, evaporation efficiency resulting in better temperature drop with respect to conventional evaporative air-cooling system.
[0019] Alternately, in the present system, the supply air is passed through cooling pad wetted by chilled water at around 7 °C, which is approximately same as dew point temperature of supply air. Hence excess humidity of air has been removed in the form of condensate. Afterwards it passes through secondary refrigerant-air heat exchanger losing further humidity in the form of condensate. Relative humidity of supply air reduces to approx. 30-40% instead of conventional air-cooling system, wherein high humid air after cooling pad is directly supplied into cabin. Hence it results into better comfort due to reduced relative humidity in closed environment conditions. The heat exchanger has been designed such that it supplies low temperature water with predefined supply logic to deliver cooled water in specific cycle to keep cooling pad wet.
[0020] The working of air-cooling system accounts for the thermal load of the cabin in two ways – evaporative air conditioning (EAC) & vapor compression refrigeration (VCR). As opposed to the conventional system, here it is the EAC, which takes care of the major component of the thermal load of the cabin which equates to almost 75%. The remaining 25% is cooled down by the conventional VCR system.
The circuit 1-2-3-4-5 shown in Fig.1 is the conventional VCR circuit comprising of the following components:
1- Electric compressor
2- Condenser (refrigerant-air heat exchanger)
3- Expansion device
4- Primary evaporator (refrigerant-water heat exchanger)
5- Secondary evaporator (refrigerant air heat exchanger)

Circuit A-B-C-D is the water circuit comprising of the following components:
A- Electric water pump
B- Drip pipe
C- Cellulose cooling pad
D- Water tank
And finally,
X – Blower
Y – Duct assembly for air passage
Water from the roof mounted tank (D) is pumped by the electric water pump (A) into the Primary evaporator (4). Here, the water is cooled down to a temperature of around 7°C & this chilled water is dripped down on to the cellulose cooling pad (C) from the drip pipe (B).
Water chilling is achieved through VCR circuit (1-2-3-4-5) shown in figure 1. Air is being sucked through the cooling pad by the blower (X) at the centre of the assembly and these evaporative cooling results in a temperature drop of up to 12°C. The chilled air then passes through the secondary evaporator (5) with a further reduction in temperature of about 3-4°C.
The water pump (A) is calibrated in such a way that it remains ON for 2 minutes & then OFF for 6 minutes. This cycle has been defined based on the following requirements:
a. Wetting of the entire cellulose pad area for evaporative cooling takes about 2 minutes.
b. The moisture content in the pads is evaporated almost completely in 6 minutes.
The primary evaporator (4), with a capacity of approx. 1.5 l of water, is designed in such a way that for the 6 minutes time that the water pump remains OFF, water is slightly dripped on to the cooling coils, leading to the formation of an ice layer on the coils. After 6 minutes, when the water pump turns ON, water gushes into the evaporator (4), leading to heat exchange between the ice layer and incoming water. This chilled water is then pumped into the drip pipe (B).
The positioning of the following heat exchangers plays an important role in improving the efficiency of the system:
a. Condenser (2) – This air-refrigerant heat exchanger is positioned in the front side so that the ram air passes through it, gets heated up by around 3-5°C, thereby increasing the moisture carrying capacity of the air by almost 30%. This directly improves evaporative air cooling by cellulose pads.
b. Secondary evaporator (5) – This air-refrigerant heat exchanger is positioned at the rear side of the assembly. Evaporative air-cooling results in significant increase in the moisture being carried by the air. This becomes a cause for passenger discomfort. Hence, the air is passed through the secondary evaporator which condenses out the moisture content, thereby providing conditioned air into the cabin.
The advantages of present invention as follows:
a. Low performance – Temperature drop achieved in evaporative cooler is around 5-7°C whereas the proposed system achieves a drop of 18-20°C – almost 4 times improvement in performance.
b. Less moisture carrying capacity of incoming air – As ram air passes through the condenser (2) and gets heated up by around 3-5°C, its moisture carrying capacity increases by almost 30%, which results in better evaporative air cooling.
c. Highly humidified air entering the cabin – As the chilled air passes through the secondary evaporator (5), it undergoes cooling by 3-4°C resulting in condensation of the moisture. Hence, air entering the cabin is both cooled & dehumidified to a comfortable level for the passengers.
In addition to the above advantages, the electric compressor used in proposed system is of 1 kW cooling capacity as opposed to around 3.2 kW capacity of the conventional mechanical compressor in VCR system – almost 65% reduction in power requirement, leading to direct improvement in the fuel efficiency of the vehicle.
In addition to the above-mentioned improvements over conventional evaporative cooler system, following advantages are also offered:
i. Low cost & energy efficient system for meeting the comfort requirement of the truck cabin occupants.
ii. Entire system is roof mounted; hence there are no complex routing pipes in the area around the engine.
iii. The air supplied to the cabin is not dry (like in conventional AC system) as it undergoes evaporative cooling.
iv. Cellulose pads are highly durable and can be easily replaced.

DESCRIPTION OF DRAWINGS
[0021] Aspects of the present disclosure are illustrated by way of example(s), and not by way of limitation, in the accompanying drawings, wherein:
[0022] FIG. 1 exemplifying working principal of the present invention
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0023] The working of air-cooling system accounts for the thermal load of the cabin in two ways – evaporative air conditioning (EAC) & vapor compression refrigeration (VCR). As opposed to the conventional system, here it is the EAC which takes care of the major component of the thermal load of the cabin which equates to almost 75%. The remaining 25% is cooled down by the conventional VCR system.
The circuit 1-2-3-4-5 shown in Fig.1 is the conventional VCR circuit comprising of the following components:
6- Electric compressor
7- Condenser (refrigerant-air heat exchanger)
8- Expansion device
9- Primary evaporator (refrigerant-water heat exchanger)
10- Secondary evaporator (refrigerant air heat exchanger)

Circuit A-B-C-D is the water circuit comprising of the following components:
E- Electric water pump
F- Drip pipe
G- Cellulose cooling pad
H- Water tank
And finally,
X – Blower
Y – Duct assembly for air passage
Water from the roof mounted tank (D) is pumped by the electric water pump (A) into the Primary evaporator (4). Here, the water is cooled down to a temperature of around 7°C & this chilled water is dripped down on to the cellulose cooling pad (C) from the drip pipe (B).
Water chilling is achieved through VCR circuit (1-2-3-4-5) shown in figure 1. Air is being sucked through the cooling pad by the blower (X) at the centre of the assembly and these evaporative cooling results in a temperature drop of up to 12°C. The chilled air then passes through the secondary evaporator (5) with a further reduction in temperature of about 3-4°C.
The water pump (A) is calibrated in such a way that it remains ON for 2 minutes & then OFF for 6 minutes. This cycle has been defined based on the following requirements:
c. Wetting of the entire cellulose pad area for evaporative cooling takes about 2 minutes.
d. The moisture content in the pads is evaporated almost completely in 6 minutes.
The primary evaporator (4), with a capacity of approx. 1.5 l of water, is designed in such a way that for the 6 minutes time that the water pump remains OFF, water is slightly dripped on to the cooling coils, leading to the formation of an ice layer on the coils. After 6 minutes, when the water pump turns ON, water gushes into the evaporator (4), leading to heat exchange between the ice layer and incoming water. This chilled water is then pumped into the drip pipe (B).
The positioning of the following heat exchangers plays an important role in improving the efficiency of the system:
c. Condenser (2) – This air-refrigerant heat exchanger is positioned in the front side so that the ram air passes through it, gets heated up by around 3-5°C, thereby increasing the moisture carrying capacity of the air by almost 30%. This directly improves evaporative air cooling by cellulose pads.
d. Secondary evaporator (5) – This air-refrigerant heat exchanger is positioned at the rear side of the assembly. Evaporative air-cooling results in significant increase in the moisture being carried by the air. This becomes a cause for passenger discomfort. Hence, the air is passed through the secondary evaporator which condenses out the moisture content, thereby providing conditioned air into the cabin.
The advantages of present invention as follows:
d. Low performance – Temperature drop achieved in evaporative cooler is around 5-7°C whereas the proposed system achieves a drop of 18-20°C – almost 4 times improvement in performance.
e. Less moisture carrying capacity of incoming air – As ram air passes through the condenser (2) and gets heated up by around 3-5°C, its moisture carrying capacity increases by almost 30%, which results in better evaporative air cooling.
f. Highly humidified air entering the cabin – As the chilled air passes through the secondary evaporator (5), it undergoes cooling by 3-4°C resulting in condensation of the moisture. Hence, air entering the cabin is both cooled & dehumidified to a comfortable level for the passengers.
In addition to the above advantages, the electric compressor used in proposed system is of 1 kW cooling capacity as opposed to around 3.2 kW capacity of the conventional mechanical compressor in VCR system – almost 65% reduction in power requirement, leading to direct improvement in the fuel efficiency of the vehicle.
In addition to the above-mentioned improvements over conventional evaporative cooler system, following advantages are also offered:
v. Low cost & energy efficient system for meeting the comfort requirement of the truck cabin occupants.
vi. Entire system is roof mounted; hence there are no complex routing pipes in the area around the engine.
vii. The air supplied to the cabin is not dry (like in conventional AC system) as it undergoes evaporative cooling.
viii. Cellulose pads are highly durable and can be easily replaced.
[0024] Although the present disclosure is described in terms of certain preferred embodiments and examples, other embodiments and examples will be apparent to those of ordinary skill in the art, given the benefit of this disclosure, including embodiments and examples that do not provide all of the benefits and features set forth herein, which are also within the scope of this disclosure. It is to be understood that other embodiments may be utilized, without departing from the true spirit and scope of the present invention.
[0025] It is to be understood that other embodiments of the present disclosure will become readily apparent to those skilled in the art from the following detailed description, wherein it is shown and described only various embodiments of the disclosure by way of illustration. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.
[0026] It would become abundantly clear to a person in the art, after reading this specification that the present subject matter also provides a cost-effective integrated air-cooling system and method of manufacturing thereof. More specifically, the present subject matter discloses a cost-effective integrated air-cooling system characterized by positioning of the heat exchanger system, which operates in fresh air mode with less than 35% electricity consumption as compared to conventional air-cooling system and without departing from the spirit of the present subject matter. While the subject matter may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described herein. Alternate embodiments or modifications may be practiced without departing from the spirit of the present subject matter. The drawings shown are schematic drawings and may not be to the scale. While the drawings show some features of the subject matter, some features may be omitted. Alternatively, in some other cases some features may be emphasized while others are not. Further, the methods disclosed herein may be performed in manner and/or order in which the methods are explained. Alternatively, the methods may be performed in manner or order different than what is explained without departing from the spirit of the present subject matter. It should be understood that the subject matter is not intended to be limited to the particular forms disclosed. Rather, the subject matter is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter.
Yours Faithfully

ANIL KUMAR PANDEY
(IN P/A 2359)
AGENT FOR THE APPLICANT(S)

CLAIMS:We claim:

1) A cost-effective integrated air-cooling system comprises air condition with a refrigerant-water heat exchanger system, wherein said air-cooling system is characterized by positioning of the heat exchanger system, which operates in fresh air mode with less than 35% electricity consumption as compared to conventional air-cooling system
2) The cost-effective integrated air-cooling system as claimed in Claim 1, wherein the working of said air-cooling system accounts for the thermal load of the cabin in two ways – evaporative air conditioning (EAC) & vapor compression refrigeration (VCR).

Yours Faithfully

ANIL KUMAR PANDEY
(IN P/A 2359)
AGENT FOR THE APPLICANT(S)