Cooling system and electronic apparatus using the same

Abstract

The invention relates to a cooling system and an electronic apparatus using the same, and particularly aims to use a thermosiphon as the cooling system and derives an optimum shape (inter-fin gap, fin height, and fin upper-end hole diameter) of a boiling heat transfer surface for different coolants. In a cooling system using a thermosiphon according to the invention, an optimum shape (inter-fin gap, fin height, and fin upper-end hole diameter) of a boiling heat transfer surface of a heat receiving jacket that forms the cooling system is identified based on a critical radius of a steam bubble produced in an overheated liquid and the diameter of an air bubble departing from the heat transfer surface for a variety of coolants.

What is claimed is: 
     
         1 . A cooling system comprising:
 a boiler portion and a condenser portion;   a steam pipe and a liquid pipe that connect the boiler portion and the condenser portion to each other; and   a heat receiving jacket,   wherein the shape of each fin formed on a boiling heat transfer surface of the heat receiving jacket is optimized in terms of a fin upper-hole diameter, an inter-fin gap, and a fin height.   
     
     
         2 . An electronic apparatus that accommodates at least one of the cooling systems according to  claim 1 . 
     
     
         3 . The cooling system according to  claim 1 ,
 wherein the shape of each fin formed on the boiling heat transfer surface is optimized in terms of the fin upper-hole diameter, the inter-fin gap, and the fin height based on a critical diameter of a steam bubble produced in an overheated liquid, the diameter of an air bubble departing from the heat transfer surface, and balance between buoyancy of the steam bubble and surface tension of the steam bubble.   
     
     
         4 . An electronic apparatus that accommodates at least one of the cooling systems according to  claim 3 . 
     
     
         5 . The cooling system according to  claim 3 ,
 wherein when a coolant is pure water, the fin upper-hole diameter is set at a value ranging from about 0.15 to 0.25 mm, the inter-fin gap is set at a value ranging from about 0.3 to 0.5 mm, and the fin height is set at a value ranging from about 0.75 to 1.2 mm, whereas when the coolant is a chlorofluorocarbon-based coolant, the fin upper-hole diameter is set at about 0.1 mm or smaller, the inter-fin gap is set at about 0.2 mm or smaller, and the fin height is set at about 0.2 mm or smaller.   
     
     
         6 . An electronic apparatus that accommodates at least one of the cooling systems according to  claim 5 . 
     
     
         7 . An electronic apparatus comprising:
 a cooling system including a boiler portion and a condenser portion, and a steam pipe and a liquid pipe that connect the boiler portion and the condenser portion to each other; and   a plurality of cooling fans that cool components in the electronic apparatus,   wherein the condenser portion is cooled with the plurality of cooling fans.   
     
     
         8 . The electronic apparatus according to  claim 7 ,
 wherein the condenser portion is located in a plurality of positions, and the plurality of condenser portions are cooled with a single cooling fan.   
     
     
         9 . The electronic apparatus according to  claim 7 ,
 wherein the steam pipe is attached to the condenser portion in a position shifted toward one of the cooling fans that has a small area facing the condenser portion.   
     
     
         10 . The electronic apparatus according to  claim 9 ,
 wherein the condenser portion is located in a plurality of positions, and the plurality of condenser portions are cooled with a single cooling fan.