Abstract: A refrigerant system includes a first, substantially outdoor, two phase heat transfer fluid vapor compression circulation loop including a compressor, a heat exchanger condenser, an expansion device, and the heat absorption side of a heat exchanger evaporator condenser, connected by conduit in a closed loop and having disposed therein a first heat transfer fluid having a critical temperature of greater than or equal to 31.2° C. The system also includes a second, at least partially indoor, two phase heat transfer fluid circulation loop that transfers heat to the first loop through the heat exchanger evaporator condenser. The second loop includes the heat rejection side of the heat exchanger evaporator condenser, a liquid pump, and a heat exchanger evaporator, connected by conduit in a closed loop and having disposed therein a second heat transfer fluid that has an ASHRAE Class A toxicity rating and an ASHRAE Class 1 or 2L flammability rating.

Abstract: A refrigerant system includes a first, substantially outdoor, two phase heat transfer fluid vapor compression circulation loop including a compressor, a heat exchanger condenser, an expansion device, and the heat absorption side of a heat exchanger evaporator condenser, connected by conduit in a closed loop and having disposed therein a first heat transfer fluid having a critical temperature of greater than or equal to 31.2° C. The system also includes a second, at least partially indoor, two phase heat transfer fluid circulation loop that transfers heat to the first loop through the heat exchanger evaporator condenser. The second loop includes the heat rejection side of the heat exchanger evaporator condenser, a liquid pump, and a heat exchanger evaporator, connected by conduit in a closed loop and having disposed therein a second heat transfer fluid that has an ASHRAE Class A toxicity rating and an ASHRAE Class 1 or 2L flammability rating.

Abstract: A heat exchanger includes a plurality of tubes positioned substantially transverse to a direction of airflow through the heat exchanger and arranged in a plurality of tube rows extending substantially along the direction of airflow. The heat exchanger further includes a plurality of webs substantially integral to two or more tubes of the plurality of tubes, each web extending between and connected to adjacent tubes of the plurality of tubes. At least one tube of the plurality of tubes has a cross section with an aspect ratio greater than 1:1, relative to a substantially horizontal web.

Abstract: An inlet header of a microchannel heat exchanger is provided with a first insert disposed within the inlet header and extending substantially the length thereof, and having a plurality of openings for the flow of refrigerant into the internal confines of the inlet header and then to the channels. A second insert, disposed within the first insert, extends substantially the length of the first insert and is of increasing cross sectional area toward its downstream end such that annular cavity is formed between the first and second insert. The annular cavity of decreasing cross sectional area provides for the maintenance of a substantially constant mass flux of the refrigerant along the length of the annulus so as to thereby maintain an annular flow regime of the liquid and thereby promote uniform flow distribution to the channels.

Abstract: A microchannel heat exchanger includes for each channel, a serpentine shaped tube for providing a plurality of parallel flow passes for successively conducting fluid flow therethrough, and being fluidly interconnected between an inlet and an outlet manifold. Multiple circuits are obtained by the individual serpentine shaped tubes. Various methods are provided for forming the serpentine shaped tubes.

Abstract: A phase separator and fluid storage volume device for a heat exchanger comprises a vessel, a vapor tube, a liquid tube, an access tube and a flow regulating device. The vessel comprises a first chamber, a second chamber, and a divider separating the first chamber from the second chamber. The vapor tube extends from within the second chamber, through the divider and the first chamber to outside the first chamber. The vapor tube also includes holes between an inlet and an outlet of the tube within the first chamber. The liquid tube extends from within the second chamber to outside of the second chamber. The access tube connects to the second chamber. The flow regulating device is disposed within the vapor tube to provide phase separation between refrigerant traveling between the first chamber and the second chamber within the vapor tube.

Abstract: An inlet header of a microchannel heat exchanger is provided with a first insert disposed within the inlet header and extending substantially the length thereof, and having a plurality of openings for the flow of refrigerant into the internal confines of the inlet header and then to the channels. A second insert, disposed within the first insert, extends substantially the length of the first insert and is of increasing cross sectional area toward its downstream end such that annular cavity is formed between the first and second insert. The annular cavity of decreasing cross sectional area provides for the maintenance of a substantially constant mass flux of the refrigerant along the length of the annulus so as to thereby maintain an annular flow regime of the liquid and thereby promote uniform flow distribution to the channels.

Abstract: A mini-channel heat exchanger or a micro-channel heat exchanger includes an insert (140, 240, 340, 440, 540, 640, 4, 940, 1040) having a volume. The insert is within a gap between a plurality of tubes (130, 230, 330, 430, 530, 630, 1, 930, 1030) of the mini-channel heat exchanger or the micro-channel heat exchanger and a manifold inner wall of a manifold (120, 220, 320, 420, 520, 620, 2, 920, 1020).