Heat exchanger for a heating, ventilation, and air-conditioning system

Abstract

An HVAC system for use with a first refrigerant and a second refrigerant. The HVAC system may include a first refrigerant circuit for use with the first refrigerant, a second refrigerant circuit for use with the second refrigerant, and a heat exchanger. The first refrigerant circuit and the second refrigerant circuit may each include may include a compressor, an expansion device, and an evaporator. The compressor may include a first upper section, a first lower section, a second upper section in fluid communication with the first lower section, and a second lower section in fluid communication with the first upper section. The first upper section, the first lower section, the second upper section, and the second lower section may be arranged such that the first refrigerant and the second refrigerant both flow through a majority of a face area of condenser while remaining in two different circuits.

What is claimed is: 
     
         1 . A heating, ventilation, and air-conditioning (“HVAC”) system for use with a refrigerant, the HVAC system comprising a multi-pass microchannel heat exchanger operable as at least one of condenser or an evaporator, the heat exchanger comprising:
 a first header at an end of the heat exchanger; 
 a second header at an opposite end of the heat exchanger; 
 a third header at the same end as the first header; 
 a first section of microchannel tubes fluidly connecting the first and second headers in a first pass for flowing the refrigerant from the first header to the second header; and 
 a second section of microchannel tubes fluidly connecting the second and third headers in a second pass for flowing the refrigerant from the second header to the third header, 
 wherein the first and third headers are arranged with a header separation between the first and third headers such that portions of the first and third headers that contain the refrigerant are not in direct contact. 
 
     
     
         2 . The HVAC system of  claim 1 , wherein the header separation comprises a gap such that the first and third headers are not directly physically connected. 
     
     
         3 . The HVAC system of  claim 2 , further comprising a non-conductive material located in the gap. 
     
     
         4 . The HVAC system of  claim 1 , wherein the header separation comprises a chamber formed between connected first and third headers. 
     
     
         5 . The HVAC system of  claim 1 , wherein the first section and the second section are spaced apart by a section separation. 
     
     
         6 . The HVAC system of  claim 5 , wherein the section separation comprises a gap. 
     
     
         7 . The HVAC system of  claim 6 , further comprising a non-conductive material located in the gap. 
     
     
         8 . The HVAC system of  claim 5 , wherein the section separation comprises one or more sections of one or more dead microchannel tubes. 
     
     
         9 . A multi-pass microchannel heat exchanger for a heating, ventilation, and air-conditioning (“HVAC”) system for use with a refrigerant and operable as at least one of a condenser or an evaporator, the heat exchanger comprising:
 a first header at an end of the heat exchanger; 
 a second header at an opposite end of the heat exchanger; 
 a third header at the same end as the first header; 
 a first section of microchannel tubes fluidly connecting the first and second headers in a first pass for flowing the refrigerant from the first header to the second header; and 
 a second section of microchannel tubes fluidly connecting the second and third headers in a second pass for flowing the refrigerant from the second header to the third header, 
 wherein the first and third headers are arranged with a first separation between the first and third headers such that portions of the first and third headers that contain the refrigerant are not in direct contact. 
 
     
     
         10 . The heat exchanger of  claim 9 , wherein the header separation comprises a gap such that the first and third headers are not directly physically connected. 
     
     
         11 . The HVAC system of  claim 10 , further comprising a non-conductive material located in the gap. 
     
     
         12 . The HVAC system of  claim 9 , wherein the header separation comprises a chamber formed between connected first and third headers. 
     
     
         13 . The HVAC system of  claim 9 , wherein the first section and the second section are spaced apart by a section separation. 
     
     
         14 . The HVAC system of  claim 13 , wherein the section separation comprises a gap. 
     
     
         15 . The HVAC system of  claim 14 , further comprising a non-conductive material located in the gap. 
     
     
         16 . The HVAC system of  claim 13 , wherein the section separation comprises one or more sections of one or more dead microchannel tubes. 
     
     
         17 . A method of operating a heating, ventilation, and air-conditioning (“HVAC”) system, comprising:
 flowing a refrigerant through a multi-pass microchannel heat exchanger to either condense or expand the refrigerant, 
 wherein flowing the refrigerant through the heat exchanger comprises:
 flowing the refrigerant to a first header at an end of the heat exchanger; 
 flowing the refrigerant from the first header to a second header at an opposite end of the heat exchanger through a first section of microchannel tubes in a first pass; 
 flowing the refrigerant from the second header to a third header at the same end as the first header through a second section of microchannel tubes in a second pass; and 
 reducing heat transfer between the refrigerant in the first header and the refrigerant in the third header by arranging a header separation between the first and third headers such that portions of the first and third headers that contain the refrigerant are not in direct contact. 
 
 
     
     
         18 . The method of  claim 17 , wherein the header separation comprises at least one of a gap such that the first and third headers are not directly physically connected or a chamber formed between connected first and third headers. 
     
     
         19 . The method of  claim 17 , further comprising reducing heat transfer between the refrigerant in the first section and the refrigerant in the second section by arranging a section separation between the first and second sections. 
     
     
         20 . The method of  claim 19 , wherein the section separation comprises at least one of a gap or one or more sections of one or more dead microchannel tubes.