FORM 2
THE PATENTS ACT, 1970
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10 and rule 13]
1. TITLE OF THE INVENTION: FREE-COOLING SYSTEM 2.
APPLICANT:
a) NAME: Global Towers Limited
b) NATIONALITY: India
c) ADDRESS:
c/o: Blue Crane: 201, 2nd floor, Peninsula Chambers,
Peninsula Corporate Park, G. K. Marg, Lower Parel (W) Mumbai: 400013
TKe following specification particularly describes the invention and the manner in which it is to be performed.

FREE-COOLING SYSTEM
CROSS-REFERENCE TO RELATED APPLICATION
This application is a complete specification claiming benefit from
provisional application number 712/Mum/2011 filed on March 14th 2011. FIELD OF INVENTION
The present invention is directed to a free-cooling system. More
particularly the present invention is directed to a free-cooling system for use in a telecommunication industry. BACKGROUND OF INVENTION
Numerous efforts have been directed towards minimizing energy
consumption in various industries. One such industry that is actively working towards minimizing and optimizing energy consumption is the telecomm industry. Typically, as is known in the art, a telecom site comprises a tower that supports the antennae for transmission and reception, and a confined space (i.e., a shelter: for indoor sites). The confined space may house at least one base transreceiver station (BTS) and other infra-equipment such as battery, switch mode power supplies (SMPS), etc. BTS and microwave equipment or fiber optic interface are typically the main communication equipment at the site. A network can be that of any of the wireless communication technologies like GSM, CDMA, WLL, WAN, WiFi, WiMAX etc.
During the working of the BTS heat is generated. The
temperature inside the confined space housing the BTS may need to be effectively controlled to avoid overheating of the space within the confined space and the BTS. A standard feature of a confined space includes an air-conditioning

unit which is employed to maintain the temperature and humidity within the confined space. The air-conditioning unit is typically powered by alternate current or direct current electric supply received from an electricity board (EB). Backup power may be supplied by a diesel generator (DG) unit or batteries, which provide power in the event of failure of the EB supply. Various attempts have been made to optimize AC unit (air-conditioning unit or aircon unit) usage. For example, in some confined spaces that are currently available in the industry, the AC unit is integrated with mechanical dampers and fans (Integrated AC unit, i.e., ACi unit wherein mechanical dampers and fans are integrated with the AC unit to form an integrated built in free-cooling system with AC unit) for ambient air circulation to achieve cooling by an inlet fan and/or outlet fan, forming a single unit. The fans are operated or the ACi unit is switched on as per the temperature of the confined space and ambient temperature conditions. For example, the temperature standard required for currently available BTS systems requires the temperature in the confined space to be maintained in a range of about 26 degrees Celsius to about 30 degrees Celsius. Further there are certain disadvantages in the ACi unit. The ACi unit may be typically located on one wall of the confined space. Effectively, inlet and outlet from the ACi unit are located on the same side of the confined space. Entry of cold air through the inlet and exit of hot air through the outlet occurs through the ACi unit located on one wall of the confined space. In such a system, as the air flow does not sweep the confined space area effectively, and since the outlet and the inlet are closely located, hot spots may be generated as described in FIG.1 to FIG.8 below. Additionally, a higher temperature gradient of about 10 degrees Celsius or even more is observed within the confined space when an ACi unit is employed.

Thus there is a need for an improved and cost effective cooling
system that may assist in minimizing the usage of the air-conditioning unit, and hence the usage of power (EB or DG), and thus help to reduce the operating costs in the telecommunication industry. SUMMARY OF INVENTION
In one embodiment, is provided a system. The system comprises
a first means for inlet of air from an ambient atmosphere to a confined space, wherein the first means comprises a filter combined with a mechanism to block the airflow when circulation of the air is not required. The system further comprises a second means for outlet of air from the confined space to the ambient atmosphere, wherein the second means comprises at least one fan. The first means and the second means are positioned at substantially opposite locations in the confined space. The system further comprises a third means comprising a controller comprising an algorithm to control the fan and an air-conditioning unit (AC unit). The third means comprises a mechanism which is configured to control the fans and direct the at least one fan to switch on or switch off based on pre-set temperature and humidity conditions within the confined space. The third means comprises the mechanism which is also configured to control the air conditioning unit and direct the air conditioning unit to switch on or switch off based on the pre-set temperature and humidity conditions within or outside the confined space.
In another embodiment, a method of maintaining a pre-set
temperature and humidity range within a confined space is provided. The method comprises providing a first means for inlet of air from an ambient atmosphere inside a confined space. The method also provides a second means

for outlet of air from the confined space to an ambient atmosphere. The first
means comprises a filter combined with a mechanism to block the airflow when
circulation of the air is not required and the second means comprises at least one
fan. The first means and the second means are positioned at substantially
opposite locations in the confined space. The method further provides a third
means comprising a controller comprising an algorithm to control the fan and an
AC unit. The third means comprises a mechanism which is configured to control
the fans and direct the at least one fan to switch on or switch off based on pre-set
temperature and humidity conditions within the confined space. The third means
comprises the mechanism which is also configured to control the air conditioning
unit and direct the air conditioning unit to switch on or switch off based on the
pre-set temperature and humidity conditions within or outside the confined space.
By employing the above discussed system and method of
switching the AC unit off when the ambient air can be effectively deployed to sweep through the confined space to achieve cooling, considerable and sizeable energy and cost savings may be achieved. BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic illustration of a free-cooling system known in
the prior art.
FIG. 2 is a schematic illustration of a free-cooling system known in
the prior art.
FIG. 3 is a pictorial representation of a thermal image of a section
in a confined space that employs a free-cooling system known in the prior art.
FIG. 4 is a pictorial representation of a thermal image of a section
in a confined space that employs a free-cooling system known in the prior art.

FIG. 5 is a pictorial representation of a thermal image of a section
in a confined space that employs a free-cooling system known in the prior art.
FIG. 6 is a pictorial representation of a thermal image of a section
in a confined space that employs a free-cooling system known in the prior art.
FIG. 7 is a pictorial representation of a thermal image of a section
in a confined space that employs a free-cooling system known in the prior art.
FIG. 8 is a pictorial representation of a thermal image of a section
in a confined space that employs a free-cooling system known in the prior art.
FIG. 9 is a schematic representation of a top-view of a free-cooling
system in accordance with embodiments of the present disclosure.
FIG. 10 is a schematic representation of a front-view of a free-
cooling system in accordance with embodiments of the present disclosure.
FIG. 11 is a pictorial representation of a first means when viewed
from outside of a confined space in accordance with embodiments of the present disclosure.
FIG. 12 is a pictorial representation of a first means when viewed
from inside of a confined space in accordance with embodiments of the present disclosure.
FIG. 13 is a pictorial representation of a second means when
viewed from outside of a confined space in accordance with embodiments of the present disclosure.
FIG. 14 is a pictorial representation of a second means when
viewed from outside of a confined space in accordance with embodiments of the present disclosure.

FIG, 15 is a pictorial representation of a third means in
accordance with embodiments of the present disclosure.
FIG. 16 is a schematic representation of a free-cooling system
connecting the first means, the second means, and the third means in
accordance with embodiments of the present disclosure.
FIG. 17 is a graphical representation illustrating various operating
modes of the free cooling system in accordance with embodiments of the present
disclosure.
FIG. 18 is a pictorial representation of a thermal image of a
section in a confined space that employs a free-cooling system in accordance
with embodiments of the present disclosure.
FIG. 19 is a pictorial representation of a thermal image of a
section in a confined space that employs a free-cooling system in accordance
with embodiments of the present disclosure.
FIG. 20 is a pictorial representation of a thermal image of a
section in a confined space that employs a free-cooling system in accordance
with embodiments of the present disclosure.
FIG. 21 is a pictorial representation of a thermal image of a
section in a confined space that employs a free-cooling system in accordance
with embodiments of the present disclosure.
FIG. 22 is a pictorial representation of a thermal image of a
section in a confined space that employs a free-cooling system in accordance
with embodiments of the present disclosure.

FIG. 23 is a pictorial representation of a thermal image of a
section in a confined space that employs a free-cooling system in accordance with embodiments of the present disclosure.
FIG. 24 is a pictorial representation of a thermal image of a
section in a confined space that employs a free-cooling system in accordance with embodiments of the present disclosure.
FIG. 25 is a pictorial representation of a thermal image of a
section in a confined space that employs a free-cooling system in accordance with embodiments of the present disclosure. DETAILED DESCRIPTION
Embodiments of the invention as disclosed herein provide an
improved system for maintaining the temperature and humidity range within a confined space below a certain pre-determined or pre-set level. A primary advantage and function of the system disclosed is to minimize use of or disable an AC unit (more particularly a discrete AC unit which is not integrated with a free-cooling system as described in the ACi unit and instead has a dedicated free-cooling system in addition to the AC unit). The system comprises a first means for inlet of air from an ambient atmosphere to a confined space, wherein the first means comprises a filter combined with a mechanism to block the airflow when circulation of the air is not required. The system further comprises a second means for outlet of air from the confined space to the ambient atmosphere, wherein the second means comprises at least one fan. The first means and the second means are positioned at substantially opposite locations in the confined space. The system further comprises a third means comprising a controller comprising an algorithm to control the fan and an air-conditioning unit

(AC unit). The third means comprises a mechanism which is configured to control the fans and direct the at (east one fan to switch on or switch off based on pre-set temperature and humidity conditions within the confined space. The third means comprises the mechanism which is also configured to control the air conditioning unit and direct the air conditioning unit to switch on or switch off based on the pre-set temperature and humidity conditions within or outside the confined space. A method of maintaining the pre-set temperature and humidity is also provided.
Referring to FIG. 1 a schematic illustration 100 of a free-cooling
system 110 known in the prior art (ACi unit) is provided. The illustration 100 indicates a confined space 112, a BTS unit 114 placed inside the confined space 112, and an ACi unit 118 placed on one wall 116 of the confined space 112. The ACi unit 118 is a modified integrated unit comprising a normal AC unit and a free-cooling system comprising mechanical dampers and fans. The illustration 100, in FIG. 1, indicates a working condition of the free-cooling system 110 when the mechanical cooling of the ACi unit 118 is enabled and the free-cooling system is disabled. The ACi unit 118 includes a compressor 122, a damper 128, a condenser fan 120, and an evaporator fan 124. In the working condition illustrated in 100, the damper 128 is in a closed position 126 which prevents outside air from entering the confined space 112 through the ACi unit 118. The hot air 136 from the confined space moves from the outlet 138 on wall 116 into the ACi unit 118, is cooled in the ACi unit 118, and the resultant cooler air 132 reenters the confined space through inlet 134. Another draft of cold air 130 enters the AC unit through inlet 142 in the ACi unit 118 and exits as hot air 140 through the condenser fan 120 after cooling the compressor 122 in the ACi unit 118.

Typically the system 100 operates in this mode when there is availability of EB supply, batteries, or energy sources available that ensure functioning of the ACi unit 118.
Referring to FIG. 2 a schematic illustration 200 of a free-cooling
system 210 known in the prior art is provided. The illustration 200 indicates a confined space 112, a BTS unit 114 placed inside the confined space 112, and an ACi unit 118 placed on one wall 116 of the confined space 112. The ACi unit 118 is a modified unit comprising a normal AC unit and a free-cooling system including mechanical dampers and fens as described above. The illustration 200, in FIG. 2, indicates a working condition of the free-cooling system 210 when the free-cooling section of the ACi unit 118 is enabled and the mechanical cooling system is disabled. As mentioned above, the ACi unit 118 includes a compressor 122, a damper 128, a condenser fan 120, and an evaporator fan 124. In the working condition illustrated in 200, the damper 128 is in open position 126 which results in outside air 212 entering into the ACi unit 118 through inlet 214 and then entering the confined space 112 through the inlet 132 as inlet air 216. The hot air 136 from the confined space moves from the outlet 138 on wall 116 into the ACi unit 118, and leaves the ACi unit 118 through outlet 218 as hot air 220 and through the condenser fan 120 as hot air 222. Thus when the free-cooling system 210 is operating in the free-cooling mode, outside air 212 {which may be relatively cooler than the hot air 136 in most instances) moves inside the ACi unit 118 in an upward direction and the hot air 134 moves through the ACi unit 118 in a downward direction and exits from outlet 218 as hot air 220 as described above. Typically in the art, the system 200 operates in this mode when there is unavailability of EB supply, batteries, or energy sources available

that result in shutting down of the ACi unit 118. One skilled in the art will
appreciate that more effort may be required to move cold air in an upward
direction and move hot air in a downward direction. Further the hot air 136 that
may be directed to the outlet 138 by the pull generated by the condenser fan 120
and may get mixed with the intet air 216 that is directed into the confined space
112 by the evaporator fan 124. The mixing of the hot and cold air may result in
minimizing the efficiency of the ACi unit 118. Further, since the inlet 132 and the
outlet 138 are located on the same wall this may result in short circuiting of the
cold air 216 entering the confined space 112 back to the outlet 138 without
moving into the confined space 112 and performing its cooling function.
Thermal imaging of the inner environment of a confined space
wherein the ACi unit 118 was employed for maintaining the temperature conditions inside the confined space, was carried out over a period of time. The thermal images, provided in FIG. 3 to FIG. 8, clearly indicate that certain areas that were hotter, resulting in minimizing the efficiency of the ACi unit 118 as described above. The conditions under which the thermal imaging was carried out are as provided in Table 1. Table 1:


A series of thermal images were captured as discussed in FIG. 3
to FIG. 8. The Table 2 below gives the conditions and times at which the different images were captured.
Table 2:

Referring to FIG. 3 a pictorial representation 300 of a thermal
image 310 of a section in a confined space that employs a free-cooling system known in the prior art, for example, ACi unit 118, under conditions and to achieve test objectives as indicated in Table 1 and Table 2 above is provided. The pictorial representation indicates the same section in visible light 312. The thermal image 310 clearly indicates a maximum temperature of 45.8 degrees 314 and a minimum temperature of 28.9 degree Celsius 316. A difference of 16.9 degrees Celsius in that portion of the confined space may be attributed to a large outside area, becoming a part of the confined space as soon as the ACi unit 118 is switched off. This may also imply that more energy may be employed to cool the same region inside the confined space, as there is no insulation and thus utilizes a lot of the ACi unit's energy even when the ACi unit is switched ON. When calculating energy losses from a confined space, these losses may also be needed to be taken into account as this is a permanent loss of energy. The

histogram 318 indicates that most of the areas within the confined space are at a temperature of about 28 degrees Celsius while some of the areas are at higher temperature of about 45 degrees Celsius immediately after ACi unit is switched OFF. This clearly indicates that a temperature gradient exists within the confined space even when the ACi unit 118 is switched ON.
Referring to FIG. 4, a pictorial representation 400 of a thermal
image 410 of a section in a confined space that employs a free-cooling system known in the prior art, for example, ACi unit 118, under conditions and to achieve test objectives as indicated in Table 1 and Table 2 above is provided. The pictorial representation indicates the same section in visible light 412. The thermal image 410 clearly indicates a maximum temperature of 38.3 degrees Celsius 414 and a minimum temperature of 27.4 degree Celsius 416. A difference of about 10 degrees Celsius in that portion, in this instant, a grill in the confined space, is quite large and may not be acceptable. The histogram 418, clearly indicates a fairly higher number of points on the grill have the minimum temperature of about 27.4 degrees Celsius when compared to the points with maximum temperature of 38.3 degrees Celsius.
Referring to FIG. 5, a pictorial representation 500 of a thermal
image 510 of a section in a confined space that employs a free-cooling system known in the prior art, for example, ACi unit 118, under conditions and to achieve test objectives as indicated in Table 1 and Table 2 above is provided. The thermal image of the portion, i.e. the grill in the confined space was carried out after a time interval of about 3 minutes after the pictorial representation 400. The pictorial representation indicates the same section in visible light 512. The thermal image 510 clearly indicates a maximum temperature of 38.9 degrees

Celsius 514 and a minimum temperature of 31.5 degree Celsius 516. Thus it
was observed that the hot areas on the grill only increased with time, though the
free-cooling system of the ACi unit 118 was ON after the mechanical cooling
system of the ACi unit 118 was switched off. The histogram 518 clearly indicates
that the number of points on the grill at the set temperature of the confined space
of about 29 degrees Celsius is clearly very high. This clearly indicates the
decreased efficiency of the free-cooling system of the ACi unit 118.
Referring to FIG. 6, a pictorial representation 600 of a thermal
image 610 of a section in a confined space that employs a free-cooling system known in the prior art, for example, ACi unit 118, under conditions and to achieve test objectives as indicated in Table 1 and Table 2 above is provided. The pictorial representation indicates the same section in visible light 612. The thermal image 610 clearly indicates a maximum temperature of 34 degrees Celsius 614 and a minimum temperature of 26.9 degrees Celsius 616. The histogram 618 shows more points in the section at a temperature of about 32 degrees Celsius to about 33 degrees Celsius when compared to points at a temperature of about 27 degrees Celsius to about 30 degrees Celsius. This indicates that re-circulation of air can become an issue if the temperature inside the ACi unit 118 involved in the free-cooling is higher. This indicates that recirculation of air should preferably not be done in a way where the air from the confined space passes through an equipment which was not inside the confined space, in this instant, the ACi unit 118.
Referring to FIG. 7, a pictorial representation 700 of a thermal
image 710 of a section in a confined space that employs a free-cooling system known in the prior art, for example, ACi unit 118, under conditions and to achieve

test objectives as indicated in Table 1 and Tabfe 2 above is provided. The pictorial representation indicates the same section in visible light 712. The minimum temperature on the section in the confined space is about 316 degrees Celsius 716 and the maximum temperature is 34.9 degrees Celsius 714. The histogram 718 clearly indicates that more portions on the section are at the maximum temperature when compared to the portions at the minimum temperature. This indicates that the confined space in which the air is driven from within the confined space itself is at a very different temperature range due to the sun's position, which is indicated by the time of imaging provided in Table 2. Re-circulation of the same air without the possibility of opening the damper due to higher outside temperature may result in heating the confined space much faster than expected.
Referring to FIG. 8, a pictorial representation 800 of a thermal
image 810 of a section in a confined space that employs a free-cooling system known in the prior art, for example, ACi unit 118, under conditions and to achieve test objectives as indicated in Table 1 and Table 2 above is provided. The pictorial representation indicates the same section, in this instant the top section of the BTS enclosure, in visible light 812. The minimum temperature on the section in the confined space is about 33.6 degrees Celsius 816 and the maximum temperature is 40.2 degrees Celsius 814. Further, the histogram 818 clearly indicates that more portions on the section are at the maximum temperature when compared to the portions at the minimum temperature. The image also indicated that the temperature above the BTS enclosure is the highest temperature in the confined space.

The free-cooling system disclosed in the instant disclosure is
configured to employ a free-cooling technique different from that known in the prior art. In other words, the system employs ambient air available outside the confined space to maintain a required pre-set temperature and humidity range. For example a typical pre-set range of temperature that is required in a confined space (i.e. a shelter) housing the BTS unit in the telecommunication industry, may have a pre-set temperature range of about 17 degrees Celsius to about 30 degrees Celsius, to be maintained within the confined space. Critical and emergency temperatures may be determined based on the requirements of the system.
In one embodiment, the third means comprises a controller
comprising an algorithm which switches ON or switches OFF the AC unit or the fan located in the outlet means in accordance with the pre-set temperature and humidity conditions required to be maintained within the confined space. Free-cooling systems available in the art were programmed to stop the fans when the temperature or humidity within the confined space was not within the required range. The free-cooling system of the instant invention maintains a pre-set temperature and humidity range within the shelter and the third means, i.e., the controller, directs the fan to switch on when ambient conditions are favourable enough to maintain the temperature within the confined space at the desired temperature range and saves the energy by directing the AC unit to switch off during the period when the ambient conditions are favourable. The same system also monitors the humidity and upon detection of either temperature or humidity of the confined space out of the required range; the fans are again switched off and the AC unit is switched on. In certain embodiments, the controller also

monitors the battery voltage and may switch off the fans to prevent battery
discharge beyond a pre-set state of charge or state of discharge value.
The free-cooling system includes at least one inlet; at least one
outlet, and a controller comprising an electronic assembly. As mentioned above, the inlet and the outlet may be located on opposite walls of the confined space. In one embodiment, the inlet may be located on a wall of the confined space that bears the door opening into the confined space and the outlet may be located on a wall directly opposite to the wall bearing the door. In another embodiment, the inlet may be located in the door of the confined space and the outlet may be located on the opposite wall of the confined space. In one embodiment, the inlet may be located in the lower half of the door and the outlet may be located closer to the ceiling resulting in the inlet and the outlet being located at diagonally opposite locations in the confined space. In one embodiment, if the confined space is constructed on a platform with air space between the bottom of the confined space and the surface over which the platform is constructed, the inlet may be located at the bottom and the outlet may be located at the top of the confined space.
In one embodiment, the inlet may include a frame, a filter, and a
mechanism to block the airflow when circulation of the air is not required. In one embodiment, the mechanism may include gravity louvers or baffles. In certain embodiments, the inlet may additionally include a fan. The primary function of the filter is to prevent dust or flying particles from the ambient atmosphere from entering the confined space. Suitable filters that may be employed include a 20 micron filter of any material, an active electrostatic filter, or a combination thereof. In embodiments where the fan may be employed, the fan used may be an axial

fan or a radial fan. The baffles or gravity louvers are mounted on the frame and are automatically open or closed based on the flow of air from outside to inside of the confined space or based on the weight of the baffles or louvers under gravity. The baffles or gravity lovers may be made of any suitable material including polymer or metal. In one embodiment, the number of inlets may depend on the requirement of amount of inlet air into the confined space. In a particular embodiment, a single inlet is formed on the door of the confined space. In one embodiment, the inlet area for air provided by the inlet means may be about half the outlet area for air provided by the outlet means.
As discussed above, the outlet may typically be located on a wall
of the confined space opposite to the wall bearing the inlet in accordance with various embodiments. In one embodiment, the number of outlets may be dependent on the requirement of amount of outlet air to be thrown out of the confined space. In one embodiment, the confined space may include one outlet. In another embodiment, the confined space may include two outlets. In yet another embodiment, the confined space may include multiple outlets, i.e., more than two outlets. In certain embodiments, the outlet means includes a fan. The outlet means may in certain embodiments, also include a filter, as described above, for the inlet means. The fan may include an axial fan, or a radial fan. In one embodiment, the fan is an axial fan. The function of the fan is to throw out the hot air from the confined space, thus creating a negative pressure of air in the confined space. The negative pressure results in the ambient air being dragged into the confined space through the inlet comprising the baffles or gravity louvers and filters.

In one embodiment, the third means comprises a controller
comprising an electronic assembly, i.e., mechanism for controlling the fan and AC unit. The electronic assembly is typically located inside the confined space. The electronic assembly, as mentioned above, includes an algorithm. The algorithm is configured to switch on or switch off the fan or the AC unit in response to the pre-set temperature and humidity range with respect to, heat load, ambient temperature, temperature, and humidity, within the confined space and battery voltage condition.
The free-cooling system functions to maintain uniform temperature
within the confined space by virtue of location of the inlet means and the outlet
means on opposite sides of the confined space. For example, the difference in
temperature observed between any two points within the confined space on
using the free-cooling system was observed to be about 1.5 degree Celsius to
about 4 degree Celsius due to the effective cross ventilation provided by the
strategic locations of inlet and outlets which make the air sweep across the
confined space. On the other hand in the, ACi unit 118 discussed above, the
difference in temperature observed between any two points within the confined
space on using the free-cooling system is about 10 degrees Celsius.
The third means is configured to minimize AC unit requirement
under various temperature conditions existing within the confined space, in relation to the temperature conditions existing in the ambient and the availability of EB and DG backup, in a first instance, a simple free-air-cooling technique is employed to maintain the temperature. In this embodiment, the inlet and outlet means may be located at opposite sides of the confined space. The heated air from within the confined space is pushed out by the outlet means, thus creating a

negative pressure inside the confined space, due to which air is taken in at the inlet means. In certain embodiments; the inlet means may also be equipped with an axial or radial fan, combined with the filter. In one embodiment, the inlet means includes only filter and baffles or gravity louvers, and the ambient air is automatically dragged in at the inlet means when the hot air is flushed out by the fans at the outlet means.
Referring to FIG. 9, a schematic representation 900 of a top-view
910 of a free-cooling system employed in a confined space 912, in accordance with embodiments of the present disclosure is provided. The free-cooling system is a discrete system not integrated with an AC unit (not shown in figure). The free-cooling system includes a first means 914, a second means 916, 918 and a third means 920. The first means 914 is disposed on a wall 922 of the confined space. The second means 916, 918 and the third means 920 are disposed on a wall 924 of the confined space that is opposite to the wall 922. Referring to FIG. 10, a schematic representation 1000 of a frontal-view 1010 of a free-cooling system employed within a confined space (not shown in figure), in accordance with embodiments of the present disclosure is provided. The free-cooling system includes a first means 914, a second means 916, 918 and a third means 920. The first means 914 is disposed on a wall 922 of the confined space. The second means 916, 918 and the third means 920 are disposed on a wall 924 of the confined space that is opposite to the wall 922.
Referring to FIG. 11, a pictorial representation 1100 of a first
means 1110 when viewed from outside 1112 of a confined space 1114 in accordance with embodiments of the present disclosure is provided. The first means 1110 (for inlet of air) fixed on the outer surface 1116 of the confined

space 1114 includes louvers 1118 that allow air from the ambient atmosphere to
be drawn into inside the confined space 1114. An optional rain canopy 1120 may
also be affixed to the first means 1110 to prevent rain water from entering the
confined space 1114, especially in locales that see heavy rainfall.
Referring to FIG. 12, a pictorial representation 1200 of a first
means 1212 when viewed from inside 1214 of a confined space 1216 in accordance with embodiments of the present disclosure is provided. The first means 1212 (for inlet of air) fixed on the inner surface 1218 of the confined space 1216 includes gravity louvers 1220 that allow air from the ambient atmosphere to be drawn into inside the confined space 1214. The gravity louvers are observed to be in a closed condition, when the fans in the second means (not shown in figure) are switched OFF. The first means 1212 also includes a filter 1222 placed between the fixed louvers on the outside of the first means {as described in FIG. 11 above) and the gravity louvers 1220.
Referring to FIG. 13, a pictorial representation 1300 of a second
means 1312 when viewed from outside 1314 of a confined space 1316 in accordance with embodiments of the present disclosure is provided. The second means 1312 (for outlet of air) fixed on the outer surface 1318 of the confined space 1316 includes gravity louvers 1320 that allow air from the confined space 1316 to be drawn outside the confined space 1316 to the ambient atmosphere. An optional rain canopy 1322 may also be affixed to the second means 1312 to prevent rain water from entering the confined space 1316, especially in locales that see heavy rainfall. More than one second means 1312 may be employed depending on the requirement of the confined space as shown in FIG. 9 and FIG. 10.

Referring to FIG. 14, a pictorial representation 1400 of a second
means 1412 when viewed from inside 1414 of a confined space 1416 in accordance with embodiments of the present disclosure is provided. The second means 1412 (for outlet of air) fixed on the inner surface 1418 of the confined space 1416 includes a rear fan frame 1420 and an electrical fan 1422, for example a 48 Volts direct current fan, that draws air from the confined space 1416 to the ambient atmosphere and simultaneously results in air from the ambient atmosphere to be drawn inside the confined space 1414 through a first means, (not shown in figure).
Referring to FiG. 15, a pictorial representation 1500 of a third
means 1512 placed inside 1514 of a confined space 1516 in accordance with embodiments of the present disclosure is provided. The third means 1512 fixed on the inside 1514 of the confined space 1516 includes a main circuit breaker 1518, a controller 1520, and a temperature sensor 1522 for sensing the temperature within the confined space 1516.
Referring to FIG. 16, a schematic representation 1600 of how the
different means of the free-cooling system 1612 are connected. A third means 1614 comprises a controller 1616 comprising an algorithm to control a second means 1618 and an AC unit 1620. The third means 1614 comprises a mechanism which is configured to control the second means 1618 and direct the at least one second means 1618 to switch on or switch off based on a pre-set temperature and humidity conditions within the confined space 1622. The third means 1614 comprises the mechanism which is also configured to control the AC unit 1620 and direct the AC unit 1620 to switch on or switch off based on the preset temperature and humidity conditions within or outside the confined space

1622. The AC unit 1620 is controlled by the third means 1614 via a contactor and relay box 1621. Based on the functioning of the second means 1618, air from the ambient atmosphere may enter the confined space 1612 through a first means 1624. The air entering the confined space 1612 through the first means 1624 sweeps through the confined space 1612 and passes over the equipments placed in the confined space before being drawn out by the second means 1618. The second means and third means may include a temperature sensor indicated by 1626 and 1628 respectively. Thus by virtue of positioning of the first and the second means the air sweeps through nearly the entire space within the confined space. Thus the free cooling system of the instant disclosure provides an improved and effective cooling for the confined space.
For example, a temperature may be set for the confined space.
Typically the maximum allowable pre-set temperature range may be between 26 degrees Celsius to about 34 degrees Celsius depending upon the requirement at a particular telecom site, with 30 degree Celsius as the most preferred pre-set value for the temperature. The third means comprising the electronic assembly is capable of monitoring the inner temperature and humidity of the confined space and adjust the flow of ambient air by switching off or switching on the fans. In one embodiment, speed control of the fans for optimised speed, when ambient temperature is favourable enough to maintain the pre-set temperature and humidity inside the confined space is also contemplated. As referred to herein, the phrase "Start Event of Free-Cooling" refers to an event when free cooling is detected when the ambient temperature is found lower than the pre-set temperature required within the confined space minus the differential temperature that the free cooling fan system can maintain between outside the confined

space and inside the confined space. As referred to herein, the phrase "Stop Event of Free-Cooling" refers to an event when the fan cooling or free-cooling does not stop immediately based on the ambient condition, but stopping of the fans is detected when the temperature within the confined space is observed to be rising above the desired pre-set temperature or humidity range and the AC unit may be switched on.
In a second example, a lowest minimum temperature may be set
for the confined space, for example, 17 degrees Celsius. The third means is programmed to switch off the fans below this temperature. As the temperature within the confined space increases during the working of the BTS, the temperature may exceed the operating temperature. In such an event, the third means, maintains the temperature by starting the fans and drawing and throwing out the ambient air using inlet means and outlet means as explained above, i.e., the third means is programmed to operate the fans in instances where the ambient temperature falls below the operating temperature minus differential temperature. In one embodiment, as long as the temperature inside the confined space is at or below operating temperature the AC unit is not used at all. This results in a huge saving of power, since neither EB nor DG backup is used during this period. The systems available in the art were programmed to start the AC unit when the temperature fell out of the pre-set range irrespective of whether cooling was required or not required.
In one embodiment, if the temperature rises above the operating
temperature when the AC unit is in functioning condition, the AC unit may be switched on. The AC unit may be switched on based on the self-learning feature of the third means.. The third means is capable of sensing the rate of rise of

temperature, when the temperature is above the pre-set temperature range. In
events, where the rate of rise is equal to or higher than a configured rate, the AC
unit may be switched on. If the rate of rise is lower than a configured rate, the
third means directs the fans to be switched on and use the ambient air to
manage/maintain temperature in the confined space to about less than an
emergency temperature, say for example, 40 degrees Celsius. As will be
appreciated by one skilled in the art, a temperature level of above 40 degrees
Celsius is typically an alarming situation, The third means is configured to sound
an alarm, when the temperature rises above the emergency critical temperature.
For example, these kinds of situations may be faced in regions having
temperature regimes like Bihar and Uttar Pradesh in summer season.
In certain embodiments, if the temperature is too low then battery
system placed in the confined space {which provide backup power to the BTS in
the absence of EB and DG set) may be affected and lose its capacity. In such
situations the third means directs the fans to switch off, and stops air from being
drawn in from the ambient to inside the confined space (typical situation faced in
regions with very low temperatures like Shimla, Kashmir in winter). The confined
space now heats up due to the working of the BTS system. When the
temperature rises above 17 degrees Celsius the fans may be directed to switch
on and the fans regulate the temperature within the confined space.
In certain embodiments, there could be emergency situations.
One such example includes a situation where AC unit is not functioning or has malfunctioned. As described above even if temperature rises above a critical temperature the third means may not command the AC unit to switch on immediately. \f \n case, the AC unit is not working and detecting an unusual rise

in temperature the third means is configured to sound an alarm. The third means
is configured to operate in emergency mode to maintain the temperature to a
below critical value in the event of AC failure. For example, typically the
emergency temperature within the confined space is about 40 degrees Celsius.
In situations where EB and AC are available in working condition (may not be
operating, but readily available when needed), when the temperature is in the
region of 30 to 40 degrees Celsius within the confined space, the third means
does not immediately command the AC unit to switch on. The third means will
sense the rise in temperature and based on self-learning capacity as discussed
above, the third means commands the fans to be switched on to reduce the
temperature to about 32 degrees Celsius to about 33 degrees Celsius within the
confined space without using the AC unit and just using EB to run the fans.
In situations where though the AC unit is switched on, a rate of
rise of temperature inside the confined space is observed, the third means gets an indication that either AC unit is not working effectively or the AC unit has failed. Thus since the third means has not disabled the AC unit, and still detects unusual temperature rise, the third means is programmed to assume that EB is not working or AC unit has failed, it commands the fans to switch on before the temperature within the confined space reaches the emergency temperature. This capability of the third means helps in reducing the high temperature possibilities within the confined space. In systems known in prior art, the fans would have started only after the temperature reaches the emergency temperature of 40 degrees Celsius or above. Accordingly, time required to bring the temperature from 40 degrees Celsius to about 30 degrees Celsius will be relatively more if the temperature is already at or above emergency temperature, than starting the fans

when the rate of rise in temperature is observed to be high in the 30 degrees
Celsius to 40 degrees Celsius range. The extended time taken to bring down the
temperature may harm the components within the confined space because of the
internal heat load. The system will rest in the emergency temperature for a
longer time when using the prior art system. The third means of the present
disclosure is programmed to switch on the fans if the temperature within the
confined space is even little more than ambient, i.e., say for example, greater
than 34 degrees Celsius. Thus the third means senses the rate of increase in
temperature and the ambient temperature before switching on the fans. The third
means directs the AC unit to switch on the AC unit only as a last resort to bring
the temperature down within the confined space, and uses the fans in most
situations to maintain the temperature to a pre-set temperature range.
In embodiments where we have discussed emergency situations
where E8 supply is not available and AC unit is not working, the third means commands the fans to switch on and maintains the temperature within the confined space below a critical temperature. Once the emergency situation is overcome, for example when the EB or AC unit resumes functioning, there is a decrease in temperature in the confined space. The decrease is sensed by the third means and the fans are commanded to switch off to decrease load on fans, and to bring the temperature within the confined space down from the emergency temperature to a temperature of about 30 degrees Celsius to 40 degrees Celsius. Using the AC unit to bring the temperature down may be more efficient in such instances than using ambient air, specifically in hot regions. This would be a zone of maximum AC unit load, and maximum power consumptions. No sooner the temperature is brought down to a manageable temperature; the third means

commands the AC unit to switch off and commands the fans to switch on. In
certain instances it may be advisable to switch on the fans and the AC units
simultaneously when coming out of an emergency situation. Rate of decrease in
temperature may be monitored, and the load on the AC unit may be reduced if
the fans are employed to distribute the cooled air within the confined space. The
fans may be commanded to stop when the temperature reaches a reasonable
temperature, and then the AC unit continues operating. For example, in some
instances in has been observed that using the fan with the AC unit reduces the
time required to come out of the emergency temperature state, say for example
by about 7 to 8 minutes earlier than when only AC unit is employed, i.e., time
when AC unit is loaded maximum, and consumes maximum power is reduced by
about 7 to 8 minutes and this brings a huge saving in terms of power consumed.
Referring to FIG 17, a graphical representation 1700 illustrating
various operating modes of a free-cooling system (as described in FIG.s 9-16 above) in accordance with embodiments of the present disclosure is provided. The graph 1700 indicates the temperature in degrees Celsius within and outside a confined space on the Y-axis 1710 and time in hours on the X-axis 1712. Curve 1714 represents the change in temperature with time in the ambient atmosphere. Curve 1716 represents the change in temperature with time within the confined space. Curve 1714 shows that the temperature of the ambient atmosphere varies throughout the day. Section 1718 of curve 1714 indicates that there is a fall in ambient temperature form about 20 to 15 degrees Celsius in a period of about 3 hours 30 minutes starting form 12:00 hours midnight to 3:30 hours in the morning. For the same time period the temperature within the confined space indicated by section 1720 of curve 1716 decreases from 24

degrees Celsius to about 18 degrees Celsius. During this period the free-cooling system of the instant disclosure was switched ON and the AC Unit was switched OFF. Since both curves 1714 and 1716 showed a decrease in temperature, the third means i.e. the controller switched OFF the free-cooling system and the AC unit for a period of about 1 hour. At the end of one hour, i.e., at about 4:30 hours it was observed from section 1722 of curve 1714 and section 1724 of curve 1716, that though the curve 1714 showed a decrease in temperature form 15 degrees Celsius to about 13 degrees Celsius, curve 1716 showed an increase in temperature to 26 degrees Celsius. The free-cooling system was then switched ON and curve 1716 showed a decrease in temperature form 26 degrees Celsius to about 18 degrees Celsius in a period of about 1 hour indicated by section 1726 of curve 1716. As the day progressed, the ambient temperature curve 1714 showed an increase in temperature for a period of about 8 hours from 13 degrees Celsius to about 25 degrees Celsius represented by section 1728 of curve 1714. Curve 1716 simultaneously showed an increase in temperature from 18 degrees Celsius to about 29 degrees Celsius indicated by section 1730 of curve 1716. The AC unit 1620 was switched on for about 4 hours and the temperature within the confined space decreased from 29 degrees Celsius to 25 degrees Celsius as indicated by section 1732 of curve 1716. During the same time the ambient temperature curve 1714 showed a steady increase from about 25 degrees Celsius to about 32 degrees Celsius indicated by section 1733 of curve 1714. Then there was a power failure for about four hours, during which period the AC unit was switched OFF and the temperature within the confined space increased to 36 degrees Celsius as indicated by section 1734 of curve 1716. The ambient temperature also showed a steady increase to about 33 degrees and more. The

free-cooling system went into an emergency cooling mode when the power failed and was switched ON using back up power, The temperature inside the confined space increased from 36 degrees Celsius to 40 degrees Celsius and then again reduced to 35 degrees Celsius as shown by section 1736 of curve 1716. The ambient temperature for the same period moved from 34 degrees Celsius to 31 degrees Celsius during the same period indicated by section 1738 of curve 1714. Thus the emergency free cooling feature of the free-cooling system of the present disclosure helped to prevent the temperature of the confined space from increasing beyond 40 degrees Celsius. The confined space was at the highest temperature of 40 degrees Celsius for a period of about 4 minutes. After 4 hours when the power supply was again available, the AC unit was switched ON. The free-cooling system and the AC unit were simultaneously on for about 15 minutes until the temperature within the confined space was below 34 degrees Celsius. With the AC unit ON the temperature within the confined space decreased to about 26 degrees Celsius as shown by section 1740 of curve 1716. The AC unit was switched off after about 2 hours. The temperature within the confined space increased to about 28 degrees Celsius and then decreased to about 25 degrees Celsius as indicated by section 1742 of curve 1716 as the free-cooling system was switched ON for about 4 hours and 30 minutes after the AC unit was switched off. During this period, the ambient temperature showed a decrease from about 31 degrees Celsius to 25 degrees Celsius and from 25 degrees Celsius to 21 degrees Celsius as indicated by sections 1744 and 1746 of the curve 1714. Thus the lower ambient temperature is effectively used in controlling the temperature within the confined space and even during the emergency situation the temperature of the confined space did not exceed the critical

temperature of 40 degrees Celsius. The AC unit and the free-cooling system may both be used to bring the confined space out of an emergency situation, i.e. a temperature greater than about 40 degrees Celsius, and thus reduce the time at which the different equipments inside the confined space are subjected to the emergency situation The set-point of the temperature within the confined space was about 29 degrees Celsius 1748. The free-cooling system disclosed herein minimizes the usage of the AC unit 1620, thereby reducing power consumption when the AC unit 1620 and the free-cooling system are discrete. As mentioned above the energy losses for maintaining dedicated exhaust i.e., the second means in combination with an AC unit 1620, instead of an integrated ACi unit 118 is much less even when the AC unit 1620 is operative.
In one embodiment, the third means may include additional
features. For example, speed profile may be controlled based on knowing the temperature region of a particular region. For example day time will be hot and night time will be cool, the fan speed can be programmed to be faster in the day and slower in the night. Another reason, for slowing down fan speed in the night, especially for confined spaces located near or on residential areas is that the fan noise in the night can be a disturbing factor. In one embodiment, reducing fan speeds may assist to reduce the noise created by the fans. In areas where ambient temperatures are very low at night, fans may be switched off till rise in temperature is sensed and fans may be switched on inteimittently as required. In another embodiment, the speed profile may be controllable with knowledge of the ambient temperature in a similar manner as described above. One or both features may be included in the algorithm and the third means may accordingly monitor the speed of the fans. The command will be provided based on

whichever profile offers lower fan speed and helps to maintain the pre-set temperature within the confined space.
In another embodiment, an additional feature may include a
pressure sensor. The pressure sensor may function to detect the level of clogging of filters by detection of change in pressure of air at inlet. The pressure sensor may be capable of detecting a situation where the fan is switched on but no air is thrown out of the outlet since entry of air is restricted by filter clogging. An alarm may be sounded by the third means before reaching this critical point. The pressure sensors may include electronic pressure sensor, water tube pressure sensor, etc.)
In yet another embodiment, an additional feature may include the
detection of humidity within the confined space. If the humidity increases beyond a pre-set critical value the fans will be commanded to switch off and the AC unit will be commanded to switch on.
Thermal imaging of the inner environment of a confined space
wherein the free-cooling system of the instant disclosure was employed for maintaining the temperature conditions inside the confined space, was carried out over a period of time. The thermal images, described under FIG. 18 to FIG. 25, clearly indicated certain areas that were hotter, resulting in minimizing the efficiency of the ACi unit as described above, as relatively cooler when the free-cooling system of the instant disclosure was employed. The conditions under which the thermal imaging was carried out are included in Table 3 below, and are the same as that used in Table 1 above.

Table 3

A series of thermal images were captured as discussed in FIG. 18
to FIG. 25. The Table 4 below gives the conditions and times at which the different images were captured. Table 4:

Referring to FIG. 18 a pictorial representation 1800 of a thermal
image 1810 of a section in a confined space that employs a free-cooling system discussed herein under conditions and to achieve test objectives as indicated in Table 3 and Table 4 above is provided. The pictorial representation indicates the same section in visible light 1812. The thermal image 1810 clearly indicates a maximum temperature of 31.0 degrees Celsius 1814 and a minimum

temperature of 26.7 degree Celsius 1816. A difference of 4.3 degrees maximum and about 1.8 degrees average is observed when the free-cooling system disclosed in the present disclosure is employed. As discussed above when the ACi unit 118, is employed the difference in the maximum and minimum temperatures is in the range of about 10 to 12 degrees Celsius. The histogram 1818 clearly indicates that the number of points around the exhaust section within the confined space with a temperature range of about 25 degrees Celsius to 29 degrees Celsius is much greater than the number of points having a temperature greater than 30 degrees Celsius.
Referring to FIG. 19 a pictorial representation 1900 of a thermal
image 1910 of a section in a confined space that employs a free-cooi'mg system discussed herein under conditions and to achieve test objectives as indicated in Table 3 and Table 4 above is provided. The pictorial representation indicates the same section in visible light 1912. The thermal image 1910 clearly indicates that the direction of movement of air is from bottom towards top and out of the confined space at location indicated by 1914. On the other hand, the colder air at the sides of the exhaust is shown to be moving downwards. The green shade indicated by 1914 in the figure from bottom to up shows the air circulation directions to be most appropriate for the application. The second means, for example a fan, has motor 1916 and the temperature of the motor is hardly at 2 degrees Celsius above the surrounding temperature within the confined space. This indicates that the difference between the temperature within the confined space and the exhaust temperature is low. The histogram 1918 clearly indicates that the number of points around the exhaust section within the confined space with a temperature range of about 26 degrees Celsius to 29 degrees Celsius is

much greater than the number of points having a temperature greater than 30 degrees Celsius. Further the points above 30 degrees Celsius are due to the heat generated by the motor of the fan 1916 in the exhaust section that forms the second means.
Referring to FIG. 20 a pictorial representation 2000 of a thermal
image 2010 of a section in a confined space that employs a free-cooling system discussed herein under conditions and to achieve test objectives as indicated in Table 3 and Table 4 above is provided. The pictorial representation indicates the same section in visible light 2012. The thermal image 2010 clearly indicates that effective air circulation is achieved to provide a gradient of about 0.9 degrees Celsius in the region 2014. The confined areas that employ ACi unit 118 for maintaining the temperature have a minimum gradient of about 6 degrees within a similar region in the confined space. The histogram 2016 clearly indicates that temperature in the region 2014 within the confined space is in a range of about 26.5 to 28.5 degrees Celsius.
Referring to FIG. 21 a pictorial representation 2100 of a thermal
image 2110 of a section in a confined space that employs a free-cooling system discussed herein under conditions and to achieve test objectives as indicated in Table 3 and Table 4 above is provided. The pictorial representation indicates the same section in visible light 2112. The thermal image 2110 clearly indicates that the temperature gradient above the BTS amplifier region 2114, is about 2.8 degrees. The confined areas that employ ACi unit 118 for maintaining the temperature have the hottest spot in the BTS with a minimum gradient of about 10 degrees. This may be attributed to the air circulation design constraints of the ACi unit 118 as discussed above. The histogram 2116 clearly indicates that the

temperature near the top of the BTS unit within the confined space is in a range of about 28 degrees Celsius to 30 degrees Celsius.
Referring to FIG. 22 a pictorial representation 2200 of a thermal
image 2210 of a section in a confined space that employs a free-cooling system
discussed herein under conditions and to achieve test objectives as indicated in
Table 3 and Table 4 above. The pictorial representation indicates the same
section in visible light 2212. The thermal image 2210 clearly indicates that the
high temperature area at 40 degrees of about 8 square inches 2214 is much less
as compared to about 192 square inches which is observed while using the ACi
unit 118 as discussed above. The histogram 2216 clearly indicates that the
number of points within the confined space with a temperature range of about 33
degrees Celsius to 34 degrees Celsius are much greater than the number of
points in the 39 degrees Celsius to 40 degrees Celsius range.
Referring to FIG. 23, a pictorial representation 2300 of a thermal
image 2310 of a section in a confined space that employs a free-cooling system discussed herein under conditions and to achieve test objectives as indicated in Table 3 and Table 4 above is provided. The pictorial representation indicates the same section in visible light 2312. The thermal image 2310 clearly indicates that the difference in maximum temperature and minimum temperature in the AC unit itself without being integrated with a free-cooling system as in ACi unit 118 is about 2 degrees Celsius 2314. As shown above, as soon as the free-cooling is integrated, the temperature difference between maximum and minimum temperatures increases to 10 degrees Celsius. This may result in a lot of energy when the ACi unit 118 is operative. The histogram 2316 clearly indicates that the AC unit (1620) grill shows a temperature range of about 31 degrees Celsius to

about 33 degrees Celsius when the AC unit and the free-cooling system are discrete.
Referring to FIG. 24, a pictorial representation 2400 of a thermal
image 2410 of a section in a confined space that employs a free-cooling system discussed herein under conditions and to achieve test objectives as indicated in Table 3 and Table 4 above is provided. The pictorial representation indicates the same section in visible light 2412. The thermal image 2410 clearly indicates that the gradient at a specific location 2414 within the confined space is maintained at about 0.7 degrees Celsius even at a temperature of about 32.7 degrees Celsius. The histogram 2416 clearly indicates that the number of points within the confined space with a temperature range of about 32.3 degrees Celsius to 33.1 degrees Celsius is much greater than the number of points having a temperature greater than 34 degrees Celsius even when the temperature within the confined space is 32.7 degrees Celsius.
Referring to FIG. 25 a pictorial representation 2500 of a thermal
image 2510 of a section of the outside wall of the confined space that houses the second means in a confined space that employs a free-cooling system discussed herein under conditions and to achieve test objectives as indicated in Table 3 and Table 4 above is provided. The pictorial representation indicates the same section in visible light 2512. The thermal image 2510 clearly indicates that, the inside air temperature is at 25 degrees and the gravity louvers at the outside of the second means are at an average of 36.9 degrees at the same time period 2514. This indicates the effectiveness of the louvers, without which the cooler air may have been blown out without cooling the confined space. The energy losses for maintaining dedicated exhaust instead of an integrated ACi unit 118 is much

less even when the AC unit is operative. The histogram 2516 clearly indicates that though the number of points on the outside facing wall of the confined space shows a temperature range of about 41 to 49 degrees Celsius the temperature range in the area at the second means i.e., the exhaust section is in the range of about 35 to 38 degrees Celsius range. Thus the free-cooling system of the instant disclosure helps to maintain the inner temperature at a value below the set-point of 29 degrees Celsius by operating the fans, the AC unit or the fans and the AC unit depending on the power supply conditions and the temperature conditions.
The foregoing embodiments meet the overall objectives of this
disclosure as summarized above. However, it will be clearly understood by those skilled in the art that the foregoing description has been made in terms only of the most preferred specific embodiments. Therefore, many other changes and modifications clearly and easily can be made that are also useful improvements and definitely outside the existing art without departing from the scope of the present disclosure, indeed which remain within its very broad overall scope, and which disclosure is to be defined over the existing art by the appended claims.

We Claim:
1. A system comprising:
a first means for inlet of air from an ambient atmosphere to a confined space, wherein the first means comprises a filter combined with a mechanism to block the airflow when circulation of the air is not required;
a second means for outlet of air from the confined space to the ambient atmosphere, wherein the second means comprises at least one fan;
wherein the first means and the second means are positioned at substantially opposite locations in the confined space; and
a third means comprising a controller comprising an algorithm to control the fan and an air-conditioning unit, wherein the third means comprise a mechanism which is configured to direct the fan to switch on or switch off based on previously set temperature conditions within the confined space; and
wherein the third means comprises the mechanism which is also configured to direct the air conditioning unit to switch on or switch off based on the previously set temperature conditions within the confined space.
2. The system of claim 1, wherein the first means is located on a door of the confined space.
3. The system of claim 2, wherein the first means is located on a lower half of the door of the confined space.

4. The system of claim 1, wherein the second means is located on a wall opposite to the door of the confined space.
5. The system of claim 1, further comprising a pressure sensing device located at the inlet means.
6. The system of claim 1, further comprising a speed monitoring means for monitoring and controlling the fan speed.
7. The system of claim 1, wherein the tnird means further comprises a means for monitoring temperature within the confined space.
8. A method of maintaining a pre-set temperature range within a confined space, the method comprising:
providing a first means for inlet of air from ah ambient atmosphere inside a confined space;
providing a second means for outlet of air from the confined space to an ambient atmosphere;
wherein the first means comprises a filter combined with a mechanism to block the airflow when circulation of the air is not required;
wherein the second means comprises at least one fan;
wherein the first means and the second means are positioned at substantially opposite locations in the confined space; and
providing a third means comprising a controller comprising an algorithm to control the fan and an air-conditioning unit, wherein the third means

comprise a mechanism which is configured to direct the fan to switch on or switch off based on previously set temperature conditions within the confined space; and
wherein the third means comprises the mechanism which is also configured to direct the air conditioning unit to switch on or switch off based on the previously set temperature conditions within the confined space.
9. The method of claim 8, further comprising a pressure sensing device located at the inlet means.
10. The method of claim 8, further comprising a speed monitoring means for monitoring and controlling the fan speed.