Description

AIR CONDITIONING SYSTEM FOR COMMUNICATION EQUIPMENT AND CONTROLLING METHOD THEREOF

Technical Field

[1] The present invention relates to an air conditioning system for communication eauipment and a method for controlling the same and more particularly, to an air conditioning system for stably cooling the communication eauipment although one of an indoor temperature sensor, an outdoor temperature sensor, and a refrigerant temperature sensor becomes out of order, and then, temperature need for cooling the communication eauipment can not be measured.

[2]

Background Art

[3] As is generally known in the art, an airconditioner employs evaporation heat which a refrigerant absorbs from surroundings when it evaporates. Typically, as refrigerant, liquids such as, ammonia, Freon, azeotropic refrigerant mixture, and chloromethyl which is easily evaporated at relatively low-temperatures.

[4] Typically, the air conditioner performs following processes: High-pressure vaporized refrigerant compressed by a compressor is changed into high-pressure refrigerant liquefied by heat exchange with outdoor air at a condenser; The high-pressure liquefied refrigerant is changed into low-pressure vaporized refrigerant by an expansion value and a capillary; and The low-pressure vaporized refrigerant flowed into an evaporator is evaporated by heat exchange with indoor air and the evaporated refrigerant is flowed back into the compressor. The refrigerant flowed into the compressor repeatedly circulates by the above processes. Air cooled by evaporation heat of the refrigerant occurred at the evaporator is blown into a predetermined space or objects to be cooled.

[5] As described above, a conventional air conditioner can cool objects by using characteristics of refrigerant to which a phase change, e.g.,condensation and evaporation easily occurs.

[6] In the meanwhile, there are many kinds of wire or wireless communication eauipment in the base communication station or communication vehicles. Typically, heat resulted from the operation of the communication eauipment may cause malfunction by breakdown of components in communication equipment or a contact error between two nodes in communication eauipment. For this reason, it is necessary to cool the communication equipment all year round to minimize malfuction if the communication equipment due to heat generation therein.

[7] There is a problem that the conventional air conditioner for communication

eauipment does not appropriately use outdoor air or indoor air to cool the communication eauipment according to surrounding temperature of the communication eauipment. Also, there is another problem that since the conventional air conditioner is continueously operated by external power source, the power consumption of the conventional air conditioner is very high and the cooling efficiency of itself is very low.

[8] In order to solve the problem described above, Applicant invented an air conditioning system for communication eauipment and a method for controlling the air conditioning system being able to reduce power consumption by operating selectively a outdoor unit and filed an application (Korea application number 10-2005-0014790) regarding the same. However, the application has a problem that if a sensor for measuring indoor temperature or indoor temperature is out of order, targeting communication eauipment can not be air-conditioned since the air condition system is stopped to operate or the air condition system performs a cooling operation continuously and then, the air condition system may have breakdown.

[9]

Disclosure of Invention Technical Problem

[10] The present invention is directed to provide an air conditioning system for communication eauipment and a method for control the air conditioning system to stably air-condition the communication eauipment although one of an indoor temperature sensor, an outdoor temperature sensor, and a refrigerant temperature sensor is out of order and then, temperature need for air-conditioning the communication eauipment can not be measured.

[H]

Technical Solution

[12] In accordance with an aspect of the present invention, there is provided an air conditioning system for communication eauipment including a first cooling unit, a second cooling unit and a third cooling unit.

[13] The first cooling unit includes an outdoor heat exchanger for exchanging heat with outdoor air, an indoor heat exchanger for exchanging heat with indoor air, a circulating pipe for circulating a first refrigerant, a circulation pump arranged on a predetermined position of the circulating pipe, a heat coil and a refrigerant temperature sensor arranged on an outdoor portion of the circulating pipe, a bypass pipe for circulating the first refrigerant to avoid passing through the outdoor heat exchanger, a first and a second bypass valves arranged on the circulating pipe and the bypass pipe, respectively, a first heat exchange tube arranged on the circulating pipe, a first brine heat exchanger having the first heat exchange tube therein, an indoor temperature sensor for

measuring indoor temperature of a base station, and an outdoor temperature sensor for measuring outdoor temperature of the base station.

[14] The second cooling unit includes a first compressor for changing a second refrigerant into a high-temperature and high-pressure second refrigerant, a first condenser for exchanging heat between outdoor air and the high-temperature and high-pressure second refrigerant, a first expansion valve for changing the seocnd refrigerant provided from the condenser into a low-temperature and low-pressure second refrigerant, and a first evaporator for exchanging heat with the first heat exchange tube wherein the first evaporator is arranged in the first brine heat exchanger installed between the first expansion valve and the first compressor.

[15] The third cooling unit includes a second compressor for changing a third refrigerant into a high-temperature and high-pressure third refrigerant; a second condenser for exchanging heat between outdoor air and the high-temperature and high-pressure third refrigerant; a second expansion valve for changing the third refrigerant provided from the second condenser into a low-temperature and low-pressure third refrigerant; a second evaporator for exchanging heat with a second heat exchange tube wherein the second evaporator is arranged in a second brine heat exchanger installed between the second expansion valve and the second compressor. Also, the first cooling unit includes the second heat exchange tube arranged at one side of the first second heat exchange tube and the second brine heat exchanger having the second heat exchange tube and the second evaporator therein.

[16] In accordance with another aspect of the present invention, there is provided a method for controlling the air conditioning system including a first step of checking whether an indoor temperature sensor is out of order or not, a second step of operating one selected among the first, second, and third units according to outdoor temperature or a combination thereof when the indoor temperature sensor is out of order; a third step of checking whether an outdoor temperature sensor is out of order or not; a fourth step of operating one selected among the first, second, and third units or a combination thereof according to indoor temperature when the outdoor temperature sensor is out of order, a five step of checking whether a refrigerant temperature sensor is out of order or not, and a six step of operating one selected among the first, second, and third units or a combination thereof according to the indoor temperature when the refrigerant temperature sensor is out of order.

[17]

Advantageous Effects

[18] An air conditioning system for communication eauipment and a controlling method thereof according to the present invention can stably air-condition the communication

eauipment although one of an indoor temperature sensor, an outdoor temperature sensor, and a refrigerant temperature sensor becomes out of order, and then, temperature needed for air-conditioning the communication eauipment can not be measured. Especially, the air conditioning system according to the present invention can stably perform a cooling operation and air-condition the communication eauipment even though the other temperature sensors except the indoor temperature sensor become out of order or the other temperature sensors except the outdoor temperature sensor become out of order.

[19]

Brief Description of the Drawings

[20] Fig. 1 is a block diagram showing an air conditioning system for communication eauipment in accordance with an embodiment of the present invention.

[21] Fig. 2 is a block diagram showing a cooling operation using a first cooling unit in an air conditioning system for communication eauipment in accordance with an embodiment of the present invention.

[22] Fig. 3 is a block diagram showing a cooling operation using a first cooling unit and a second cooling unit in an air conditioning system for communication eauipment in accordance with an embodiment of the present invention.

[23] Fig. 4 is a block diagram showing a cooling operation using a first cooling unit to a third cooling unit in an air conditioning system for communication eauipment in accordance with an embodiment of the present invention.

[24] Figs. 5 to 7 are a flow chart illustrating a method for controlling an air conditioning system for communication eauipment in accordance with an embodiment of the present invention.

[25]

Best Mode for Carrying Out the Invention

[26] Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to drawings provided according to the embodiment of the present invention.

[27] Fig. 1 is a block diagram showing an air conditioning system for communication eauipment in accordance with an embodiment of the present invention.

[28] As shown, the air conditioning system for communication eauipment in accordance with an embodiment of the present invention includes a first cooling unit 100 for directly cooling the communication eauipment (not shown), and a second and a third cooling units 200 and 300 for indirectly cooling the communication eauipment by cooling a first refrigerant of the first cooling unit 100. The first, second, and third cooling units 100, 200, 300 are arranged in an indoor unit 500 and an outdoor unit 600.

The indoor unit 500 is arranged with the communication eauipment in a base station. The outdoor unit 600 is arranged outside the base station. The indoor unit 500 includes a temperature sensor 510 for measuring indoor temperature and the outdoor unit 600 includes a temperature sensor 610 for measuring outdoor temperature.

[29] The first cooling unit 100 is first described hereinafter. An indoor heat exchanger 110 arranged in the indoor unit 500 is a component for heat exchange between indoor air and the first refrigerant. A first temperature sensor 112 is arranged at an inlet of the indoor heat exchanger 110 and a second temperature sensor 114 is arranged at an outlet of the indoor heat exchanger 110. Indoor fans 116 are arranged at one side of the indoor heat exchanger 110 for transferring air cooled by heat exchange of the indoor heat exchanger 110. Outdoor heat exchangers 120 are arranged at the outdoor unit for heat exchange between outdoor air and the first refrigerant. The outdoor heat exchangers 120 are arranged in series or in parallel with reference to a position of outdoor fans 122. The indoor heat exchanger 110 and the outdoor heat exchangers 120 are connected by a circulating pipe 130 filled with the first refrigerant.

[30] As described above, the circulating pipe 130 is filled with the first refrigerant and the first refrigerant circulates through the circulating pipe 130. A circulation pump 132 compulsively circulates the first refrigerant through the circulating pipe 130. A pressure switch 134 measures pressure of the first refrigerant at the inlet of the indoor heat exchanger 110. A flow switch 136 measures the flow amount of the first refrigerant at the outlet of the indoor heat exchanger 110.

[31] A heat coil 180 and a refrigerant temperature sensor 190 are arranged on the portion of the circulating pipe 130 installed in the out door unit 600, and the heat coil 180 prevents the circulation pipe 130 from being broken by cold weather. Also, a first heat exchange tube 162 and a second heat exchanged tube 164 are arranged in series on the circulating pipe 130 wherein the first heat exchange tube 162 is for exchanging heat with a first evaporator 240 of the second cooling unit 200 and the second heat exchange tube 164 is for exchanging heat with a second evaporator 340 of the third cooling unit 300. The first brine heat exchanger 172 has the first heat exchange tube 162 therein and the second brine heat exchanger 174 has the second heat exchange tube 164 therein.

[32] A bypass pipe 140 is arranged for circulating the first refrigerant so that the first refrigerant avoid passing through the outdoor heat exchangers 120. A first bypass valve 152 is provided on the circulation pipe 130 and a second bypass valve 154 is provided on the bypass pipe 140. The first bypass valve 152 and the second bypass valve 154 can be opened at the same time or a selected one of the two valves 152 and 154 can be opened.

[33] The second cooling unit 200 includes a first compressor 210 for changing a second

refrigerant into a high-temperature and high-pressure second refrigerant, a first condenser 220 for exchanging heat between outdoor air and the high-temperature and high-pressure second refrigerant, a first expansion valve 230 for changing the second refrigerant provided from the first condenser 220 into a low-temperature and low- pressure second refrigerant, the first evaporator 240 arranged in the first brine heat exchanger 172 exchanges heat with the first heat exchange tube 162. Herein, the first evaporator 240 is arranged between the first expansion valve 230 and the first compressor 210.

[34] The third cooling unit 300 includes a second compressor 310 for changing a third refrigerant into a high-temperature and high-pressure third refrigerant, a second condenser 320 for exchanging heat between outdoor air and the high-temperature and high-pressure third refrigerant, a second expansion valve 330 for changing the third refrigerant provided from the condenser into a low-temperature and low-pressure third refrigerant, and the second evaporator 340 arranged between the second expansion valve 330 and the second compressor 310. Herein, the second evaporator 340 is for exchanging heat with a second heat exchange tube 164 and is arranged in a second brine heat exchanger 174.

[35] The first refrigerant used in the first cooling unit 100 according to the present invention includes water. The second refrigerant used in the second cooling unit 200 and the third refrigerant used in the third cooling unit 300 includes one selected from the group consisting of ammonia, azeotropic refrigerant and chloride methyl, or combinations thereof.

[36] A cooling operation of the air conditioning system according to the present invention is described hereinafter. The cooling operation is controlled according to indoor temperature and the outdoor heat exchangers 120 is controlled according to outdoor temperature and the temperature of the first refrigerant. Herein, the first refrigerant includes brine.

[37] First, the indoor temperature of the base station is measured. If the measured indoor temperature is higher than a first reference temperature, e.g., 25 degrees, the first cooling unit 100 is operated (Referring to Fig. 2). This case is called a first cooling operation. In this case, if outdoor temperature is lower than that of the first refrigerant, the first bypass valve 152 is opened and the outdoor heat exchangers 120 is operated. Herein, the second bypass valve 154 is closed. If outdoor temperature is higher than that of the first refrigerant, the second bypass valve 154 is opened and the operation of the outdoor heat exchangers 120 is stopped. Herein the first bypass valve 152 is closed.

[38] If the measured indoor temperature is higher than a second reference temperature, e.g., 26.5 degrees, the first cooling operation is not sufficient to cool the indoor space of the base station. In this case, both of the first cooling unit 100 and the second

cooling unit 200 are operated. This case is called a second cooling operation (Referring to Fig. 3). While the first cooling unit 100 and the second cooling unit 200 are operated, heat exchange between the first refrigerant and the second refrigerant is performed in the first brine heat exchanger 172. The first refrigerant cooled by the above heat exchange is used to cool communication eauipment in the base station.

[39] Also, if the measured indoor temperature is higher than a third reference temperature, e.g., 27.5 degrees, the second cooling operation is not sufficient to cool the indoor space of the base station. In this case, all of the first, second, and third cooling units 100, 200, and 300 are operated. This case is called a third cooling operation. During the third cooling operation, heat exchange between the first refrigerant and the second refrigerant is first performed in the first brine heat exchanger 172 and heat exchange between the first refrigerant and the third refrigerant is secondly performed in the second brine heat exchanger 174. The first refrigerant cooled by the above heat exchanges is used to cool communication eauipment in the base station.

[40] As described above, if outdoor temperature is lower than that of the first refrigerant during the second cooling operation and the third cooling operation, the first bypass valve 152 is opened and the outdoor heat exchangers 120 is operated. If outdoor temperature is higher than that of the first refrigerant during the second cooling operation and the third cooling operation, the second bypass valve 154 is opened and the operation of the outdoor heat exchangers 120 is stopped.

[41] Referring to Figs 1 to 7, hereinafter, it is described a method for control the air conditioning system to stably cool the communication eauipment although one of an indoor temperature sensor, an outdoor temperature sensor, and a refrigerant temperature sensor becomes out of order.

[42] A method for control the air conditioning system according to the present invention a first step of checking whether an indoor temperature sensor is out of order or not, a second step of operating at least one selected among the first, second, and third units or a combination thereof according to outdoor temperature when the indoor temperature sensor is out of order, a third step of checking whether an outdoor temperature sensor is out of order or not, a fourth step of operating one selected among the first, second, and third units or a combination thereof according to indoor temperature when the outdoor temperature sensor is out of order, a fifth step of checking whether a refrigerant temperature sensor is out of order or not, and a sixth step of operating one selected among the first, second, and third units or a combination thereof according to indoor temperature when the refrigerant temperature sensor is out of order.

[43] On the first step and the second step as shown in Fig. 5, it is checked whether the indoor temperature sensor 510, the outdoor temperature sensor 610 and the refrigerant temperature sensor 190 are out of order or not (S 102). If the indoor temperature sensor

510 is out of order (S 104), the outdoor temperature T measured by the outdoor out temperature sensor 610 is compared with a first set temperature T and a second set temperature T (S 106, S 110, S 114). The first cooling unit 100 is operated if the e2 outdoor temperature T is lower than the first set temperature T , e.g., 10 degrees out el

(S 108). The first and second cooling units 100 and 200 or the first and third cooling units 100 and 300 are operated if the outdoor temperature T is between the first set out temperature T and the second set temperature T , e.g., 17 degrees (Sl 12). The first, el e2 second, and third cooling units 100, 200, and 300 are operated if the outdoor temperature T is higher than the second set temperature T (Sl 16). Herein, while the out e2 first cooling unit 100 is operated, only the first bypass valve 152 is opened. While the first and second cooling units 100 and 200 are operated, while the first and the third cooling units 100 and 300 are operated, or while the first, second, and third cooling units 100, 200, and 300 are operated, only the second bypass valve 154 is opened. [44] On the third step and the fourth step as shown in Fig. 6, it is checked whether the indoor temperature sensor 510, the outdoor temperature sensor 610 and the refrigerant temperature sensor 190 are out of order or not (S 102). If the outdoor temperature sensor 610 is out of order (Sl 18), the indoor temperature T measured by the indoor temperature sensor 510 is compared with the first reference temperature T , the second reference temperature T and the third reference temperature T (S 120, S 124, S 128).

The first cooling unit 100 is operated if the indoor temperature T is between the first reference temperature T , e.g., 25 degrees and the second reference temperature T , si s2 e.g., 26.5 degrees (S 122). The first and second cooling units 100 and 200 or the first and third cooling units 100 and 300 are operated if the indoor temperature T is between the second reference temperature T and the third reference temperature T , e.g., 27.5 degrees (S 126). The first, second, and third cooling units 100, 200, and 300 are operated if the indoor temperature T is higher than the third reference temperature T (S 130). Herein, since the first bypass valve 154 is opened while the first cooling unit 100 is operated in case that the indoor temperature T is between the first out reference temperature T and the second reference temperature T , the cooling si s2 operation of the first cooling unit 100 is not carried out.

[45] On the third step and fourth step as shown in Fig. 7, it is checked whether the indoor temperature sensor 510, the outdoor temperature sensor 610 and the refrigerant temperature sensor 190 are out of order or not (S 102). If the refrigerant temperature sensor 190 is out of order (S 132), the indoor temperature T measured by the indoor temperature sensor 510 is compared with a first reference temperature T si , a second reference temperature Ts2 and a third reference temperature T 3 (S 120, S 124, S 128) in a similar way that the outdoor temperature sensor 610 is out of order. The first cooling unit 100 is operated if the indoor temperature T out is between the first reference

temperature T , e.g., 25 degrees and the second reference temperature T , e.g., 26.5 si s2 degrees (S 136). The first and the second cooling units 100 and 200 or the first and the third cooling units 100 and 300 are operated if the indoor temperature T is between the second reference temperature T and the third reference temperature T , e.g., 27.5 s2 s3 degrees (S 140). The first to the third cooling units 100, 200, and 300 are operated if the indoor temperature T is higher than the third reference temperature T (S 144). m s3

Herein, since the first bypass valve 154 is opened while the first cooling unit 100 is operated in case that the indoor temperature T is between the first reference out temperature T and the second reference temperature T , the cooling operation of the si s2 first cooling unit 100 is not carried out.

[46] In case that the outdoor temperature sensor 610 and the refrigerant temperature sensor 190 are out of order, the operation of the outdoor heat exchangers 120 should be stopped on condition that the first bypass valve 152 is closed and the second bypass valve 154 is opened. It can prevent the cooled or warmed first refrigerant from flowing into the circulation pipe 130 in the indoor unit 500. The breakdown of the outdoor temperature sensor 610 and the refrigerant temperature sensor 190 may cause the cooled or warmed first refrigerant to flow into the circulation pipe 130 in the indoor unit 500. It means that the air condition system can not control the communication eauipment to be cooled.

[47] While the present invention has been described with respect to certain preferred embodiments, it will be apparent to those skilled in the air that various changes and modifications may be made without departing from scope of the invention as defined in the following claims.