Heat exchanger and refrigeration apparatus

Abstract

A heat exchanger includes a first fluid layer having a first fluid passage through which a first fluid flows, and a second fluid layer having a second fluid passage through which a second fluid that undergoes a phase change flows. The first and second fluid layers are alternately stacked, and the heat exchanger exchanges heat between the first and second fluids. The second fluid passage is divided into a plurality of channel sections from a first channel section to an N-th channel section by a structure that makes the second fluid turn around (N-1) times. N is a natural number greater than or equal to two. The first channel section is near a condensation outlet or an evaporation inlet. The N-th channel section is near a condensation inlet or an evaporation outlet. A channel cross-sectional area of the first channel section is smaller than the N-th channel section.

1 . A heat exchanger comprising:
 a first fluid layer having a first fluid passage through which a first fluid flows; and   a second fluid layer having a second fluid passage through which a second fluid that undergoes a phase change flows, the first fluid layer and the second fluid layer being alternately stacked, and the heat exchanger exchanging heat between the first fluid and the second fluid,   the second fluid passage being divided into a plurality of channel sections from a first channel section to an N-th channel section by a structure that makes the second fluid turn around (N-1) times, with N being a natural number greater than or equal to two,   the first channel section being near a condensation outlet or an evaporation inlet,   the N-th channel section being near a condensation inlet or an evaporation outlet, and   a channel cross-sectional area of the first channel section being smaller than a channel cross-sectional area of the N-th channel section.   
     
     
         2 . The heat exchanger of  claim 1 , wherein
 the channel cross-sectional area of the first channel section is 25% or less of the channel cross-sectional area of the N-th channel section.   
     
     
         3 . The heat exchanger of  claim 1 , wherein
 the first channel section has a plurality of first unit passages having a substantially constant channel cross-sectional area and extending along a direction of flow of the second fluid,   the N-th channel section has a plurality of N-th unit passages having a substantially constant channel cross-sectional area and extending along the direction of flow of the second fluid,   a channel cross-sectional area of each of the first unit passages is substantially equal to a channel cross-sectional area of each of the N-th unit passages, and   a number of the first unit passages is less than a number of the N-th unit passages.   
     
     
         4 . The heat exchanger of  claim 1 , wherein
 the first channel section has a plurality of first unit passages having a substantially constant channel cross-sectional area and extending along a direction of flow of the second fluid,   the N-th channel section has a plurality of N-th unit passages having a substantially constant channel cross-sectional area and extending along the direction of flow of the second fluid,   a number of the first unit passages is substantially equal to a number of the N-th unit passages, and   a channel cross-sectional area of each of the first unit passages is smaller than a channel cross-sectional area of each of the N-th unit passages.   
     
     
         5 . The heat exchanger of  claim 1 , wherein
 the first channel section has a plurality of first unit passages having a substantially constant channel cross-sectional area and extending along a direction of flow of the second fluid,   the N-th channel section has a plurality of N-th unit passages having a substantially constant channel cross-sectional area and extending along the direction of flow of the second fluid,   a channel cross-sectional area of each of the first unit passages is smaller than a channel cross-sectional area of each of the N-th unit passages, and   a number of the first unit passages is less than a number of the N-th unit passages.   
     
     
         6 . The heat exchanger of  claim 1 , wherein
 N is a natural number greater than or equal to three, and   a channel cross-sectional area decreases gradually from the N-th channel section toward the first channel section.   
     
     
         7 . A refrigeration apparatus including the heat exchanger of  claim 1 , the refrigeration apparatus further comprising:
 a fluid circuit to which the heat exchanger is connected and through which the second fluid flows.