Parallel-flow type heat exchanger and air conditioner equipped with same

Abstract

A parallel-flow type heat exchanger ( 1 ) is provided with two vertical-direction header pipes ( 2, 3 ), and a plurality of horizontal-direction flat tubes ( 4 ) that connect the header pipes with each other. The plurality of horizontal direction flat tubes are divided into a plurality of groups each comprising a plurality of flat tubes, and each of the groups constitutes a coolant path that lets coolant flow from one vertical-direction header pipe to the other. The upper limit for the number of flat tubes that constitute a coolant path for one turn is obtained from a prescribed numerical formula.

1 . A parallel-flow heat exchanger of a side-flow type, comprising:
 two header pipes extending in a vertical direction; and   a plurality of flat tubes extending in a horizontal direction and coupling together the header pipes with each other,   wherein   the plurality of flat tubes are grouped such that each group comprises a plurality of flat tubes, each group constituting a one-turn refrigerant path through which refrigerant is passed from one to the other of the two header pipes extending in the vertical direction,   an upper limit of a number of flat tubes constituting the one-turn refrigerant path is determined to be within a range of ±2 of a value calculated using,   when the parallel-flow heat exchanger is used in an outdoor unit of an air conditioner, the formula
   n<3.0×10 −4 ×Q+8.0,  (A)
 
   and   when the parallel-flow heat exchanger is used in an indoor unit of an air conditioner, the formula
   n<4.2×10 −4 ×Q+7.9,  (A)
 
   where   n represents the number of flat tubes constituting the one-turn refrigerant path; and   Q represents rated capacity, given in watts (W).   
     
     
         2 . The parallel-flow heat exchanger according to  claim 1 , wherein
 the heat exchanger is used in an outdoor unit of an air conditioner, and   a lower limit of the number of flat tubes constituting the one-turn refrigerant path is determined using the formula
   n≧(αQ+β)×[(1.4×10 −16 )×L/(d×A′ 2 )] 0.5 .  (B)
 
   where   α=0.0161;   β=8.86;   d represents a hydraulic diameter, given in meters (m); and   A′ represents a refrigerant passage cross-sectional area of one flat tube, given in square meters (m 2 ).   
     
     
         3 . The parallel-flow heat exchanger according to  claim 1 , wherein
 the heat exchanger is used in an indoor unit of an air conditioner, and   a lower limit of the number of flat tubes constituting the one-turn refrigerant path is determined using the formula
   n≧(αQ+β)×[(1.4×10 −16 )×L/(d×A′ 2 )] 0.5 .  (B)
 
   where   α=0.0228;   β=6.62;   d represents a hydraulic diameter, given in meters (m); and   A′ represents a refrigerant passage cross-sectional area of one flat tube, given in square meters (m 2 ).   
     
     
         4 . An air conditioner comprising a parallel-flow heat exchanger according to  claim 2  as an outdoor unit of the air conditioner. 
     
     
         5 . An air conditioner comprising a parallel-flow heat exchanger according to  claim 3  as an indoor unit of the air conditioner.