DESC:FIELD OF INVENTION
The present invention relates to Base Transceiver Station (BTS) of the telecommunication towers. More particularly, the present invention relates to a BTS fan shut Air Conditioner (AC) system for controlling temperature of BTS shelter by regulating operation of fans and AC by sensing the ambient and the shelter temperature. Advantageously, the present invention minimizes the cost required for controlling temperature of the BTS shelter housing.

BACKGROUND OF INVENTION
A wireless communication system typically includes a communication network providing coverage of a designated geographic region and a plurality of subscriber units. The wireless communication system generally enables the subscriber unit to communicate with other communication devices, such as Internet and mobile phones, via the communication network. Communication between the subscriber units and the communication network typically occur over radio frequency (RF) channels that provide physical paths over which communication signals such as voice, data and video are transmitted.

The communication network includes a plurality of telecommunication towers having BTS. The BTS is a piece of equipment that facilitates wireless communication between user equipment (UE) and a network. Typically the user equipments (UE) are devices like mobile phones, Wireless Local Loop (WLL) phones, and computers with wireless Internet connectivity. The network can be that of any of the wireless communication technologies like Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Wireless Fidelity (Wi-Fi), Worldwide Interoperability for Microwave Access (WiMAX) or other wide area network (WAN) technology.

The BTS provide communication coverage of a specific geographic area. The area covered by the communication network is typically divided into a number of smaller communication sites where each communication site is serviced by at least one BTS. Each BTS includes at least one radio transceiver stations for enabling communication with the one or more subscriber units operating within the associated cell. The BTS(s) are coupled to at least one base station controller (BSC). Depending on the configuration of the communication network, a BSC may be adapted to control the single BTS or a cluster of multiple BTS(s).

Each BSC is further interfaced to a mobile switching center (MSC). The MSC communicatively couples the BSC to a public switched telephone network (PSTN) and potentially to other communication networks. Typically apart from the transceiver, the BTS comprises parts/ systems like power amplifier (PA), combiner, duplexer, antenna, alarm extension system and baseband receiver unit etc.

The Large BTS units are installed outdoors as well as indoors, where ambient temperatures can range from -40 C to +50"C depending upon the location of the BTS. A heating/cooling temperature management system is required to regulate the internal temperature of the shelter during the BTS operation for proper functioning of the electronic components housed within the BTS shelter. If the heating/cooling temperature management system is not efficient it will results in the down time of the tower which will results in lot of in convince to the users/customers such as call drop, non availability of service resulting in loss of reputation to the service provider, So it is essential that BTS shelter heating/cooling temperature management systems should work seamlessly.

Conventional BTS shelter heating/cooling temperature management system comprises an AC in order to maintain the shelter temperature within the set band. The BTS shelter heating/cooling temperature management systems employs two DC fans which run in tandem with the air conditioner and are installed on the wall of the shelter that comprises the air conditioner.

Though the DC fans push the hot air outside the shelter, it may not give adequate pressure drop for the inlet air flow inside the BTS shelter. Further there is no sensing arrangement provided to sense the ambient temperature/shelter temperature and to stop the DC fans in case if the ambient temperature is higher than that of the shelter temperature. This will not only results in unnecessary loss of energy resulting in higher operating cost but also result in high failure rates, high maintenance costs and shorter life span of the DC Fans due to its continuous running.

Normally two cutouts are taken on the door of the shelter to allow the entry of outside air inside the shelter. To filter dust and other foreign matters, wire meshes are fitted on the cut out area. Being wire mesh, it has its own limitation on its ability to filter the foreign material entering the shelter. Also the wire mesh will be permeable for the flow of cool air produced by the air conditioner which will increase the cost of operation of the temperature control system. More over the wire mesh has to be cleaned on regular basis to ensure free flow of cool outside air through it inside the shelter to reduce the running time of the air conditioner.
Although there is BTS shelter heating/cooling temperature management system, there is a need for an efficient BTS fan shut AC system for controlling temperature of the BTS shelter with minimal cost.

OBJECTS OF INVENTION
One or more of the problems of the conventional prior art may be overcome by various embodiments of the present invention.

The primary object of the present invention is directed to provide an efficient BTS fan shut Air Conditioner (AC) system for controlling temperature of the BTS shelter.

It is another object of the present invention to provide a BTS fan shut AC system for controlling temperature of the BTS shelter by regulating operation of fans and AC by sensing the ambient temperature and the shelter temperature.

SUMMARY OF INVENTION
Thus according to the embodiment of the present invention there is provided a Base Transceiver Station (BTS) Fan Shut Air Conditioner (AC) system comprising of a shelter, shelter housing, an inlet fan; an exhaust fan; an air conditioner; a first temperature sensor; a second temperature sensor; a control unit; battery bank; and power interface unit (PIU),
wherein said shelter housing comprising at least a first wall and a second wall,
wherein the inlet fan is fitted on the first wall of the shelter housing,
wherein the exhaust fan is fitted at a pre-defined location on the second wall of the shelter housing,
wherein the air conditioner is fitted on the second wall of the shelter housing at a pre-defined location from the exhaust fan,
wherein the first temperature sensor (Sa) which is disposed to sense the ambient temperature (Ta) is fitted at a pre-defined location at outer surface of the shelter housing,
wherein the second temperature sensor (Ss) which is disposed for sensing the shelter temperature (Ts) second is fitted at a pre-defined location at inner surface of the shelter housing, and
wherein output from the first temperature sensor (Sa) and the second temperature sensor (Ss) is fed to the control unit to control the working of the inlet fan and the air conditioner.

It is another aspect of the present invention, wherein the inlet fan is fitted on entry door of the shelter at a pre-defined location

It is another aspect of the present invention, wherein the output of first temperature sensor and second temperature sensor is fed to the control unit which is programmed to control the operation of the inlet fan, exhaust fan and air conditioner.

It is another aspect of the present invention, wherein the control unit triggers the inlet fan to direct ambient air from the atmosphere to the shelter when the ambient temperature (Ta) is less than pre-set temperature with respect to the shelter temperature (Ts).

It is another aspect of the present invention, wherein the control unit triggers the exhaust fan always in ‘ON’ state to direct the heat from the shelter to the atmosphere.

It is another aspect of the present invention, wherein the control unit also comprises a Microcontroller or Programmable Logic Controller (PLC).
It is another aspect of the present invention, wherein an air filter is fitted at a pre-determined location on outer part of the shelter to prevent the entry of micro dusts into the shelter, the size of which includes but not limited to approximately 5 micron.

It is another aspect of the present invention, wherein the control unit reverses direction of rotation of the inlet fan for pre-determined time interval and duration to automatically clean the dust particles accumulated on the air filter.

It is another aspect of the present invention, further comprising a first rain hood fitted above the opening of the inlet fan on the outer part of the shelter and a second rain hood fitted above the exhaust fan on the outer part of the shelter.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1: Schematically illustrates the Base Transceiver station (BTS) fan shut AC system for controlling temperature of the BTS shelter according to the prior art.
Figure 2: Schematically illustrates the Base Transceiver station (BTS) fan shut AC system for controlling temperature of the BTS shelter according to the present invention.
Figure 3: Schematically illustrates the inlet fan and exhaust fan positioned in the Base Transceiver station (BTS) fan shut AC system for controlling temperature of the BTS shelter according to the present invention.
Figure 4: Schematically illustrates the rain hood and air filter positioned in the door of Base Transceiver station (BTS) fan shut AC system for controlling temperature of the BTS shelter according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
Figure 1 schematically illustrates the BTS fan shut AC according to the prior art, wherein two cut outs are taken on the doors to allow the air from the ambient inside the shelter. Two DC fans are installed on the same wall to push the air outside the shelter.

The present invention is directed to an efficient BTS fan shut AC system for controlling temperature of the BTS shelter by regulating operation of fans and AC by sensing the ambient temperature and the shelter temperature.

Referring to Figure 2, the BTS fan shut AC system comprises of a shelter (S), shelter housing (1), Base Transceiver Station (BTS) (2), an inlet fan (3), an exhaust fan (4), an air conditioner (5), a first temperature sensor (6), a second temperature sensor (6’), a control unit (7), an air filter (8), one or more rain hoods (9,9’), a battery bank (10), a power interface unit (PIU) (11) and security lights, said shelter housing (1) comprises of a first wall (1a) and a second wall (1b), As shown in Figures 2 and 3, the inlet fan (3) which is used to direct the outside air from the atmosphere into the shelter housing (1) is fitted on the entry door (12) of the shelter housing (1). The entry door (12) is fitted on the first wall (1a) of the shelter housing (1) at a pre-defined location. The exhaust fan (4) which is used to discharge the hot air from the shelter to the atmosphere is fitted at a pre-defined location on the second wall (1b) of the shelter housing (1). The air conditioner (5) is also is fitted on the second wall (1b) of the shelter housing (1) at a pre-defined location from the exhaust fan (4). The second wall (1b) is located opposite to the first wall (1a). The inlet fan (3) and exhaust fan (4) includes but not limited to DC fan.

The air conditioner (5) is used to cool the shelter (S) by removing the heat generated by the equipments of the system including the battery bank (10) which indisposed to energize the equipment and security lights with required electrical power. By removing the heat present inside the shelter (S), the air conditioner (5) maintains the inside temperature of the shelter (S) at a pre-determined temperature for trouble free performance of the equipments present inside the shelter. The inlet fan (3), the air conditioner (5) and the exhaust fan (4) are located at a pre-determined distance from each other.

The first temperature sensor (Sa) (6) is disposed to sense the ambient temperature (Ta) and second temperature sensor (Ss) (6’) is disposed for sensing the shelter temperature (Ts). The first temperature sensor (Sa) (6) is fitted at a pre-defined location at the outer surface of the shelter (S) and the second temperature sensor (Ss) (6’) provided to sense the shelter temperature is fitted at a pre-defined location at the inner surface of the shelter (S).The output of the first temperature sensor (Sa) (6) and the second temperature sensor (Ss) (6’) is fed to the control unit (7). The control unit (7) also comprises the controller which may be a Microcontroller or Programmable Logic Controller (PLC). The Microcontroller or Programmable Logic Controller (PLC) is programmed to control the operation in manner so as to maintain the shelter temperature within the pre-set temperature limit.

The shelter temperature (Ts) and the ambient temperature (Ta) are monitored by the control unit (7) and the output of the control unit (7) is fed to the inlet fan (3) and the exhaust fan (4) as well as to the air conditioner (5). The inlet fan (3) is triggered to ‘ON’ state by the control unit (7) when the ambient temperature (Ta) is less than pre-set temperature with respect to the shelter temperature (Ts). During working of BTS, the control unit (7) keeps the exhaust fan (4) always in ‘ON’ state to direct the hot air from the shelter to the atmosphere. The control unit (7) triggers the air conditioner (5) to ‘ON’ state only when the shelter temperature (Ts) is above the pre-set temperature with respect to the ambient temperature (Ta). This facilitates savings in the power consumed by the air conditioner (5).

As shown in Figures 3 and 4, the air filter (8) is fitted at a pre-determined location on the outer part of the shelter (S)to filter the impurities present in ambient air in order to prevent the entry of micro dusts into the shelter (S).The air filter (8) may be of multi layer in construction capable of filtering micro dusts of size which includes but not limited to the size approximately 5micron.In a preferred embodiment, the BTS Fan Shut AC system comprises of two rain hoods (9, 9’) to avoid rain water entry in to the inner surface of the shelter (S) through the openings provided for the passage of exhaust air / fresh air. While the first rain hood (9) is fitted above the opening of the exhaust fan (4) on the outer part of the shelter (S), the second rain hood (9’) is fitted above the inlet fan (3) on the outer part of the shelter (S).

The control unit (7) is provided with means for reversing the direction of rotation of the inlet fan (3) for pre-determined time interval and duration to facilitate automatically cleaning the dust particles accumulated on the air filter (8). The rotation of the inlet fan (3) in the opposite direction cleans the air filter by blowing away the accumulated micro dusts. The control unit (7) controls the operation of inlet fan (3) and air conditioner (5) in tandem to maintain the shelter temperature (Ts) within the pre-set temperature thereby saves the energy.

The advantages of the present invention are as follows:
• Fans and air conditioners work in tandem to maintain the shelter temperature (Ts) within the pre-set temperature to save energy.
• Minimizes the cost required for controlling temperature of the BTS shelter.
• Less maintenance due to automatic cleaning of the air filter.
• Energy saving due to minimal operation of AC.

The embodiments of the invention been disclosed in detail in this specification are purely for illustrative purposes and the present invention can be embodied in many other forms or carried out in other ways, without departing from the spirit or essential characteristics thereof. Therefore, the above should not be construed as limiting the invention, which is defined by the appended objects.
,CLAIMS:WE CLAIM:
1. Base Transceiver Station (BTS) Fan Shut Air Conditioner (AC) system comprising of:
a shelter (S); shelter housing (1);
an inlet fan (3);
an exhaust fan (4);
an air conditioner (5);
a first temperature sensor (6);
a second temperature sensor (6’);
a control unit (7);
battery bank (10); and
power interface unit (PIU) (11),
wherein said shelter housing (1) comprising at least a first wall (1a) and a second wall (1b),
wherein the inlet fan (3) is fitted on the first wall (1a) of the shelter housing (1),
wherein the exhaust fan (4 ) is fitted at a pre-defined location on the second wall (1b) of the shelter housing (1),
wherein the air conditioner (5) is fitted on the second wall (1b) of the shelter housing (1) at a pre-defined location from the exhaust fan (4),
wherein the first temperature sensor (Sa) (6) which is disposed to sense the ambient temperature (Ta) is fitted at a pre-defined location at outer surface of the shelter housing (1),
wherein the second temperature sensor (Ss) (6’) which is disposed for sensing the shelter temperature (Ts) second is fitted at a pre-defined location at inner surface of the shelter housing (1), and
wherein output from the first temperature sensor (Sa) (6) and the second temperature sensor (Ss) (6’) is fed to the control unit (7) to control the working of the inlet fan (3) and the air conditioner (5).

2. The Base Transceiver Station (BTS) Fan Shut AC as claimed in claim 1, wherein the inlet fan (3) is fitted on entry door of the shelter at a pre-defined location

3. The Base Transceiver Station (BTS) Fan Shut AC as claimed in claim 1, wherein the output of first temperature sensor (6) and second temperature sensor (6’) is fed to the control unit (7) which is programmed to control the operation of the inlet fan (3), exhaust fan (4) and air conditioner (5).

4. The Base Transceiver Station (BTS) Fan Shut AC as claimed in claim 3, wherein the control unit (7) triggers the inlet fan (3) to direct ambient air from the atmosphere to the shelter (S) when the ambient temperature (Ta) is less than pre-set temperature with respect to the shelter temperature (Ts).

5. The Base Transceiver Station (BTS) Fan Shut AC as claimed in claim 3, wherein the control unit (7) triggers the exhaust fan (4) always in ‘ON’ state to direct the heat from the shelter to the atmosphere.

6. The Base Transceiver Station (BTS) Fan Shut AC as claimed in claim 5, wherein the control unit (7) also comprises the Microcontroller or Programmable Logic Controller (PLC).

7. The Base Transceiver Station (BTS) Fan Shut AC as claimed in claim 1, wherein an air filter (8) is fitted at a pre-determined location on outer part of the shelter (S) to prevent the entry of micro dusts into the shelter, the size of which includes but not limited to approximately 5 micron.

8. The Base Transceiver Station (BTS) Fan Shut AC as claimed in claim 1, wherein the control unit (7) reverses direction of rotation of the inlet fan (3) for pre-determined time interval and duration to automatically clean the dust particles accumulated on the air filter (8).

9. The Base Transceiver Station (BTS) Fan Shut AC as claimed in claim 1, further comprising a first rain hood (9) fitted above the opening of the inlet fan (3) on the outer part of the shelter (S) and a second rain hood (9’) fitted above the exhaust fan (4) on the outer part of the shelter(S).