Fixed orifice refrigerant distribution system

Abstract

An HVAC system having a fixed orifice expansion device coupled to an evaporator coil is provided. In one embodiment, an expansion device coupled to an evaporator coil includes a flow restrictor and an evaporator inlet manifold. The flow restrictor includes multiple fixed orifices aligned with the refrigerant distribution tubes to restrict flow of refrigerant from the evaporator inlet manifold into the refrigerant distribution tubes through the multiple fixed orifices. Additional systems, devices, and methods are also disclosed.

1 . An apparatus comprising:
 an evaporator coil; and   an expansion device coupled to the evaporator coil, the expansion device including an evaporator inlet manifold and a flow restrictor that restricts flow of refrigerant from the evaporator inlet manifold into refrigerant distribution tubes that are in fluid communication with the evaporator coil, wherein the refrigerant distribution tubes include a first refrigerant distribution tube and a second refrigerant distribution tube, the flow restrictor includes a first fixed orifice and a second fixed orifice in a shared body, the first fixed orifice is positioned with respect to the first refrigerant distribution tube so as to restrict flow of refrigerant from the evaporator inlet manifold into the first refrigerant distribution tube through the first fixed orifice, and the second fixed orifice is positioned with respect to the second refrigerant distribution tube so as to restrict flow of refrigerant from the evaporator inlet manifold into the second refrigerant distribution tube through the second fixed orifice, and wherein the first fixed orifice and the second fixed orifice have different sizes.   
     
     
         2 . The apparatus of  claim 1 , wherein the evaporator coil is a multi-circuit evaporator coil that includes a first refrigerant circuit and a second refrigerant circuit that are independent of one another within the evaporator coil. 
     
     
         3 . The apparatus of  claim 2 , wherein the first refrigerant distribution tube is coupled to provide refrigerant to the first refrigerant circuit of the evaporator coil and the second refrigerant distribution tube is coupled to provide refrigerant to the second refrigerant circuit of the evaporator coil. 
     
     
         4 . The apparatus of claim  7 , wherein the first fixed orifice and the second fixed orifice have different sizes such that, in operation, pressure drop of refrigerant passing through the first fixed orifice is different from pressure drop of refrigerant passing through the second fixed orifice. 
     
     
         5 . The apparatus of  claim 3 , wherein the multi-circuit evaporator coil includes a third refrigerant circuit and a fourth refrigerant circuit that are independent of one another, and independent of the first refrigerant circuit and the second refrigerant circuit, within the evaporator coil. 
     
     
         6 . The apparatus of  claim 5 , wherein the refrigerant distribution tubes include a third refrigerant distribution tube and a fourth refrigerant distribution tube, the third refrigerant distribution tube is coupled to provide refrigerant to the third refrigerant circuit of the evaporator coil and the fourth refrigerant distribution tube is coupled to provide refrigerant to the fourth refrigerant circuit of the evaporator coil, the flow restrictor includes a third fixed orifice and a fourth fixed orifice in the shared body, the third fixed orifice is positioned with respect to the third refrigerant distribution tube so as to restrict flow of refrigerant from the evaporator inlet manifold into the third refrigerant distribution tube through the third fixed orifice, and the fourth fixed orifice is positioned with respect to the fourth refrigerant distribution tube so as to restrict flow of refrigerant from the evaporator inlet manifold into the fourth refrigerant distribution tube through the fourth fixed orifice. 
     
     
         7 . An apparatus comprising:
 an evaporator coil; and   an expansion device coupled to the evaporator coil, the expansion device including an evaporator inlet manifold and a flow restrictor that restricts flow of refrigerant from the evaporator inlet manifold into refrigerant distribution tubes that are in fluid communication with the evaporator coil, wherein the refrigerant distribution tubes include a first refrigerant distribution tube and a second refrigerant distribution tube, the flow restrictor includes a first fixed orifice and a second fixed orifice in a shared body, the first fixed orifice is positioned with respect to the first refrigerant distribution tube so as to restrict flow of refrigerant from the evaporator inlet manifold into the first refrigerant distribution tube through the first fixed orifice, and the second fixed orifice is positioned with respect to the second refrigerant distribution tube so as to restrict flow of refrigerant from the evaporator inlet manifold into the second refrigerant distribution tube through the second fixed orifice;   wherein the evaporator coil is a multi-circuit evaporator coil that includes a first refrigerant circuit and a second refrigerant circuit that are independent of one another within the evaporator coil, the first refrigerant distribution tube is coupled to provide refrigerant to the first refrigerant circuit of the evaporator coil, and the second refrigerant distribution tube is coupled to provide refrigerant to the second refrigerant circuit of the evaporator coil;   wherein the multi-circuit evaporator coil includes a third refrigerant circuit and a fourth refrigerant circuit that are independent of one another, and independent of the first refrigerant circuit and the second refrigerant circuit, within the evaporator coil;   wherein the refrigerant distribution tubes include a third refrigerant distribution tube and a fourth refrigerant distribution tube, the third refrigerant distribution tube is coupled to provide refrigerant to the third refrigerant circuit of the evaporator coil and the fourth refrigerant distribution tube is coupled to provide refrigerant to the fourth refrigerant circuit of the evaporator coil, the flow restrictor includes a third fixed orifice and a fourth fixed orifice in the shared body, the third fixed orifice is positioned with respect to the third refrigerant distribution tube so as to restrict flow of refrigerant from the evaporator inlet manifold into the third refrigerant distribution tube through the third fixed orifice, and the fourth fixed orifice is positioned with respect to the fourth refrigerant distribution tube so as to restrict flow of refrigerant from the evaporator inlet manifold into the fourth refrigerant distribution tube through the fourth fixed orifice; and   wherein the first fixed orifice, the second fixed orifice, the third fixed orifice, and the fourth fixed orifice are not evenly spaced measured longitudinally along the shared body.   
     
     
         8 . The apparatus of  claim 2 , wherein the first refrigerant circuit differs from the second refrigerant circuit. 
     
     
         9 . The apparatus of  claim 1 , wherein the first fixed orifice and the second fixed orifice are at different angular positions in the shared body. 
     
     
         10 - 13 . (canceled) 
     
     
         14 . The apparatus of  claim 1 , wherein at least one of the first fixed orifice or the second fixed orifice includes a pair of intersecting slots. 
     
     
         15 . (canceled) 
     
     
         16 . The apparatus of  claim 1 , wherein the shared body of the flow restrictor includes a round tube having the first fixed orifice and the second fixed orifice. 
     
     
         17 . The apparatus of  claim 1 , wherein the shared body of the flow restrictor includes a curved plate having the first fixed orifice and the second fixed orifice. 
     
     
         18 . The apparatus of  claim 1 , wherein the shared body of the flow restrictor is received within the evaporator inlet manifold. 
     
     
         19 . The apparatus of  claim 1 , wherein the evaporator coil and the expansion device are installed in fluid communication with a compressor in an HVAC system. 
     
     
         20 . (canceled) 
     
     
         21 . The apparatus of  claim 1 , comprising a compressor and a condenser coil. 
     
     
         22 . The apparatus of  claim 21 , wherein the apparatus includes a packaged HVAC unit with the compressor, the condenser coil, the evaporator coil, and the expansion device installed in a shared cabinet. 
     
     
         23 . The apparatus of  claim 21 , wherein the apparatus includes a split system in which the compressor and the evaporator coil are in separate cabinets. 
     
     
         24 . A method comprising:
 providing a flow restrictor having a plurality of fixed orifices in a shared body; and   installing the flow restrictor at an evaporator inlet manifold such that the plurality of fixed orifices are positioned to restrict flow of refrigerant from the evaporator inlet manifold to an evaporator coil, wherein the plurality of fixed orifices includes a first fixed orifice and a second fixed orifice having different sizes, the first fixed orifice is positioned to restrict flow of refrigerant from the evaporator inlet manifold to the evaporator coil through the first fixed orifice and a first inlet of the evaporator coil, and the second fixed orifice is positioned to restrict flow of refrigerant from the evaporator inlet manifold to the evaporator coil through the second fixed orifice and a second inlet of the evaporator coil.   
     
     
         25 . The method of  claim 24 , wherein installing the flow restrictor at the evaporator inlet manifold includes inserting the flow restrictor into the evaporator inlet manifold. 
     
     
         26 . The method of  claim 25 , wherein inserting the flow restrictor into the evaporator inlet manifold includes aligning the first fixed orifice with a first refrigerant distribution tube in fluid communication with the evaporator coil and aligning the second fixed orifice with a second refrigerant distribution tube in fluid communication with the evaporator coil.