Cooling system and method for cooling radio unit

Abstract

At least one heat generating radio unit in an active antenna system unit, the cooling system comprising at least one fan and an air duct, where each heat generating radio unit to be cooled by the cooling system is arranged connected to a heat sink unit comprising cooling fins, the heat sink unit being arranged to transfer heat between the radio unit and the ambient air, where the at least one fan is arranged to generate a primary air flow of ambient air in the air duct between at least one air duct inlet and at least one air duct outlet, where the air duct is arranged to extend in the longitudinal direction (A) of the active antenna system unit along each of the said heat sink units and to border on each of the said heat sink units.

1 . Cooling system for cooling at least one heat generating radio unit in an active antenna system unit, the cooling system comprising at least one fan and a single air duct,
 wherein each heat generating radio unit to be cooled by the cooling system is arranged connected to a heat sink unit comprising cooling fins, the heat sink unit being arranged to transfer heat between the radio unit and the ambient air,   wherein the at least one fan is arranged to generate a primary air flow of ambient air in the single air duct between at least one air duct inlet and at least one air duct outlet,   wherein the at least one air duct inlet, the single air duct and the at least one air duct outlet are arranged to extend in a same longitudinal direction (A) of the active antenna system unit along a same side which borders each of the heat sink units,   wherein the primary air flow generated in the single air duct is arranged to flow substantially along the same longitudinal direction (A) of the active antenna system unit and is further arranged to generate along the same side which borders each of the heat sink units, a secondary air flow of ambient air over a number of cooling fins of each of the said heat sink units,   wherein the cooling fins are obliquely arranged and oriented at an angle with respect to the longitudinal direction (A) of the active antenna system unit.   
     
     
         2 . Cooling system according to  claim 1 , wherein the at least one air duct outlet is arranged to direct a flow of ambient air over a number of cooling fins of each of the said heat sink units. 
     
     
         3 . Cooling system according to  claim 2 , wherein the at least one air duct outlet is arranged along a longitudinal side of the active antenna system unit. 
     
     
         4 . Cooling system according to  claim 2 , wherein the gap size (B) of the air duct outlet is arranged with varying dimensions along the longitudinal direction (A) of the active antenna system unit. 
     
     
         5 . Cooling system according to  claim 4 , wherein the air duct outlet is arranged with narrowing gap size (B) along the longitudinal direction (A) of the active antenna system unit. 
     
     
         6 . Cooling system according to  claim 2 , wherein a cover is arranged at the air duct to direct the secondary air flow over the cooling fins. 
     
     
         7 . Cooling system according to  claim 2 , wherein the angle (α) between a cooling fin and the longitudinal direction (A) of the active antenna system unit is arranged to vary along the extension (C) of the cooling fin. 
     
     
         8 . Cooling system according to  claim 2 , wherein a cooling fin is arranged with varying dimensions along the longitudinal extension (C) of the cooling fin. 
     
     
         9 . Cooling system according to  claim 2 , wherein a cooling fin is arranged in a wave formed shape or arranged in a curved shape along the longitudinal extension (C) of the cooling fin. 
     
     
         10 . Cooling system according to  claim 2 , wherein the at least one fan is a centrifugal fan. 
     
     
         11 . Cooling system according to  claim 1 , wherein the at least one air duct inlet is arranged to suck a secondary air flow of ambient air over a number of cooling fins of each of the said heat sink units. 
     
     
         12 . Cooling system according to  claim 11 , wherein the at least one air duct inlet is arranged along a longitudinal side of the active antenna system unit. 
     
     
         13 . Cooling system according to  claim 11 , wherein the gap size (B) of the air duct inlet is arranged with varying dimensions along the longitudinal direction (A) of the active antenna system unit. 
     
     
         14 . Cooling system according to  claim 11 , wherein the air duct inlet is arranged with narrowing gap size (B) along the longitudinal direction (A) of the active antenna system unit. 
     
     
         15 . Cooling system according to  claim 11 , wherein a cover is arranged at the air duct to direct the secondary air flow over the cooling fins. 
     
     
         16 . Cooling system according to  claim 11 , wherein the angle (α) between a cooling fin and the longitudinal direction (A) of the active antenna system unit is arranged to vary along the extension (C) of the cooling fin. 
     
     
         17 . Cooling system according to  claim 11 , wherein a cooling fin is arranged with varying dimensions along the longitudinal extension (C) of the cooling fin. 
     
     
         18 . Cooling system according to  claim 11 , wherein a cooling fin is arranged wave formed or with curved shape along the longitudinal extension (C) of the cooling fin. 
     
     
         19 . Cooling system according to  claim 11 , wherein the at least one fan is a centrifugal fan. 
     
     
         20 . Method for cooling at least one heat generating radio unit in an active antenna system unit using a cooling system, the cooling system comprising at least one fan and a single air duct, characterized by comprising the steps of:
 connecting each heat generating radio unit to be cooled by the cooling system to a heat sink unit comprising cooling fins;   arranging the heat sink unit to transfer heat between the radio unit and the ambient air;   arranging the at least one fan to generate a primary air flow of ambient air in the single air duct between at least one air duct inlet and at least one air duct outlet;   arranging the at least one air duct inlet, the single air duct and the at least one air duct outlet to extend in a same longitudinal direction (A) of the active antenna system unit along a same side which borders each of the heat sink units;   arranging the primary air flow generated in the single air duct to flow substantially along the same longitudinal direction (A) of the active antenna system unit;   arranging the primary air flow to generate along the same side which borders each of the heat sink units, a secondary air flow of ambient air over a number of cooling fins of each of the said heat sink units; and   arranging the cooling fins to be cooled by the secondary air flow, wherein the secondary fins are obliquely oriented at an angle (α) with respect to the longitudinal direction (A) of the active antenna system unit.   
     
     
         21 . Method for cooling a heat generating unit ( 4 ) according to  claim 20 , further comprising the step of arranging the at least one air duct outlet to direct a flow of ambient air over a number of cooling fins of each of the said heat sink units. 
     
     
         22 . Method for cooling a heat generating unit ( 4 ) according to  claim 17 , further comprising the step of arranging the at least one air duct inlet to suck a secondary air flow of ambient air over a number of cooling fins of each of the said heat sink units.