Evaporator and centrifugal chiller provided with the same

Abstract

The present invention maintains a compact evaporator size in a centrifugal chiller utilizing a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG while avoiding efficiency losses and equipment damage that result from carryover of liquid state refrigerant to the turbo compressor side. This evaporator is equipped with a pressure vessel into which a condensed refrigerant is introduced, a refrigerant inlet which is provided to the bottom portion of the pressure vessel, a refrigerant outlet which is provided to the top portion of the pressure vessel, a heat transfer pipe group which passes through the interior of the pressure vessel, circulates liquid to be chilled through the interior thereof, and exchanges heat between the liquid to be chilled and the refrigerant, and a demister which is disposed between the refrigerant outlet and the heat transfer pipe group in the interior of the pressure vessel and carries out vapor-liquid separation of the refrigerant, a dividing section (for example, a plurality of notches) being provided between the periphery of the demister and the inner peripheral surface of the pressure vessel. The dividing section is provided to a side of the demister along the lengthwise direction.

1 . An evaporator comprising:
 a pressure container into which a condensed refrigerant is introduced;   a refrigerant inlet which is provided in a lower portion of the pressure container;   a refrigerant outlet which is provided in an upper portion of the pressure container,   a group of heat transfer pipes which passes through an inside of the pressure container and circulates a cooling target liquid inside the group of heat transfer pipes to cause the cooling target liquid to be subjected to heat exchange with the refrigerant; and   a demister which is installed between the refrigerant outlet and the group of heat transfer pipes inside the pressure container and performs gas-liquid separation of the refrigerant,   wherein a separation portion is provided between a circumferential portion of the demister and an inner circumferential surface of the pressure container.   
     
     
         2 . The evaporator according to  claim 1 ,
 wherein the pressure container has a cylindrical shell shape extending in a horizontal direction, and   wherein the separation portion is provided on a side of the demister along an axis direction of the pressure container.   
     
     
         3 . The evaporator according to  claim 1 ,
 wherein the pressure container has a cylindrical shell shape extending in a horizontal direction,   wherein the group of heat transfer pipes is installed to pass through the inside of the pressure container in a longitudinal axis direction, and   wherein the separation portion is provided to be biased to an upstream portion side of the group of heat transfer pipes.   
     
     
         4 . The evaporator according to  claim 1 ,
 wherein the pressure container has a cylindrical shell shape extending in a horizontal direction,   wherein the group of heat transfer pipes includes a group of outbound pipes extending from one end to the other end in the longitudinal axis direction inside the pressure container, and a group of inbound pipes communicating with the group of outbound pipes at the other end in the longitudinal axis direction inside the pressure container and returning from the other end to the one end in the longitudinal axis direction inside the pressure container, and   wherein the group of outbound pipes is disposed below and the group of inbound pipes is disposed above inside the pressure container.   
     
     
         5 . The evaporator according to  claim 1 ,
 wherein the demister is disposed immediately above the group of heat transfer pipes.   
     
     
         6 . A centrifugal chiller comprising:
 a turbo compressor which compresses a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG;   a condenser which condenses the compressed low pressure refrigerant; and   the evaporator according to  claim 1 , which evaporates the expanded low pressure refrigerant.