Heat exchanger unit

Abstract

According to the present invention, there is provided a heat exchanger unit having, over a base, a surface-modified portion composed of a metal, the surface-modified portion being brought into contact with a flow path provided for a liquid refrigerant, wherein the liquid refrigerant is a liquid having a surface tension smaller than that of water, and the surface-modified portion has a porous structure, in which a plurality of recesses are provided on the flow path side thereof, each recess has an introduction path having a cross-section area gradually reduced from the inlet of the recess, and a cavity communicated with the introduction path while placing an inflection portion in between, and the shortest distance between the inflection portion and the flow path is larger than the shortest distance between the cavity and the flow path.

1 . A heat exchanger unit having, over a base, a surface-modified portion composed of a metal, said surface-modified portion being brought into contact with a flow path provided for a liquid refrigerant,
 wherein said liquid refrigerant is a liquid having a surface tension smaller than that of water, and   said surface-modified portion has a porous structure, in which a plurality of recesses are provided on the flow path side thereof,   each recess has an introduction path having a cross-section area gradually reduced from the inlet of said recess, and a cavity communicated with said introduction path while placing an inflection portion in between, and   the shortest distance between said inflection portion and said flow path is larger than the shortest distance between said cavity and said flow path.   
   
   
       2 . The heat exchanger unit as claimed in  claim 1 ,
 wherein said liquid refrigerant is an organic refrigerant, and said organic refrigerant is a hydrofluoroether or fluorine-containing inert liquid.   
   
   
       3 . The heat exchanger unit as claimed in  claim 1 ,
 wherein said recess has a pore size of 1 μm to 10 μm.   
   
   
       4 . The heat exchanger unit as claimed in  claim 1 ,
 further comprising a flow path of micro-channel type as a forced-convection boiling refrigerant type cooling unit, and said surface-modified portion is provided along said flow path.