Abstract: A method of controlling power applications for a power transformer in a heating ventilation and cooling system (HVAC). The method includes measuring a voltage output of a transformer, the transformer configured to supply control power to a component of the HVAC system, determining a loading of the transformer; prioritizing a loading of the transformer; and applying the prioritization to mitigate loading constraints associated with the transformer.

Abstract: A method of controlling power applications for a power transformer in a heating ventilation and cooling system (HVAC). The method includes measuring a voltage output of a transformer, the transformer configured to supply control power to a component of the HVAC system, determining a loading of the transformer; prioritizing a loading of the transformer; and applying the prioritization to mitigate loading constraints associated with the transformer.

Abstract: A heat pump is provided including a plurality of lines having refrigerant flowing therethrough. A reversing valve is provided including a selector mechanism having a plurality of cavities formed therein and extending therethrough. A source of motion is coupled to the selector mechanism for movement of the selector mechanism. Each one of the plurality of cavities fluidly couples at least two of the plurality of lines. The selector mechanism is movable between a cooling mode and a heating mode so that the cavities fluidly couple different ones of the plurality of lines in each of the cooling mode and the heating mode. The selector mechanism will maintain its position with respect to the plurality of lines when the source of motion is de-energized, regardless of a pressure differential between different ones of the plurality of lines.

Abstract: A microchannel heat exchanger includes a plurality of microchannel tubes including a first set of microchannel tubes and a second set of microchannel tubes. A first circuit of the microchannel heat exchanger includes the first set of microchannel tubes, and a portion of a first fluid flows through the first set of microchannel tubes and exchanges heat with a second fluid. A second circuit of the microchannel heat exchanger includes the second set of microchannel tubes, and a reminder of the first fluid flows through the second set of microchannel tubes and exchanges heat with the second fluid. The first fluid from the first circuit and the first fluid from the second circuit combine into a common flow.

Abstract: In a parallel flow heat exchanger having an inlet manifold connected to an outlet manifold by a plurality of parallel channels, a spirally shaped insert is disposed within the refrigerant flow path in the inlet manifold such that a swirling motion is imparted to the refrigerant flow in the manifold so as to cause a more uniform distribution of refrigerant to the individual channels. Various embodiments of the spirally shaped inserts are provided, including inserts designed for the internal flow of refrigerant therethrough and/or the external flow of refrigerant thereover.

Abstract: An inlet header (22) of a microchannel heat pump heat exchanger has a tube (34) disposed therein and extending substantially the length of the inlet header (22), with the tube (34) having a plurality of openings (36) therein. During cooling mode operation, refrigerant is caused to flow into an open end of the tube (34) and along its length to thereby flow from the plurality of openings (36) into the inlet header (22) prior to entering the microchannels (24) to thereby provide a uniform flow of two-phase refrigerant thereto. A bi-flow expansion device (41) placed at the inlet end of the tube (34) allows for the expansion of liquid refrigerant into the tube (34) during periods in which the heat exchanger operates as an evaporator and allows the refrigerant to flow directly from the header (22) and around the tube (34) during periods in which the heat exchanger operates as a condenser coil.

Abstract: A microchannel heat exchanger includes a two headers and tubes that extend between the headers. Each tube has an elongated cross-section, the cross-section having a first end and an opposing second end. In one example, each tube is angled such that a line defined between the ends of each tube is angled relative to the horizontal. As the tubes are angled, water that collects on the tubes is directed away from the tubes. In another example, a plate fin directs water away from the tubes. The plate fin includes openings, and a louver including parallel vertical slots is located between each of the openings. Each tube is interference fit in one of the openings of the plate fin, positioning a louver between each tube.

Abstract: A heat exchanger includes a first header and a second header and a plurality of heat exchange tubes extending therebetween. Each heat exchange tube has an inlet end opening to one of the headers and an outlet opening to the other header. Each heat exchange tube has a plurality of channels extending longitudinally in parallel relationship from its inlet end to its outlet end, each channel defining a discrete refrigerant flow path. The inlet end of each of the plurality of heat exchange tubes is positioned with the inlet opening to the channels disposed in spaced relationship with and facing an opposite inside surface of the header thereby defining a relatively narrow gap between the inlet opening to the channels and the facing opposite inside surface of the header. The gap may function either as a primary expansion device or as a secondary expansion device.

Abstract: A microchannel heat exchanger has at least two manifolds, with the at least two manifolds communicating with a respective one of a first and second plurality of heat exchange tube banks. The first and second plurality of heat exchange tube banks are intertwined within a single microchannel heat exchanger core.

Abstract: In a parallel flow heat exchanger having an inlet manifold connected to an outlet manifold by a plurality of parallel channels, a spirally shaped insert is disposed within the refrigerant flow path in the inlet manifold such that a swirling motion is imparted to the refrigerant flow in the manifold so as to cause a more uniform distribution of refrigerant to the individual channels. Various embodiments of the spirally shaped inserts are provided, including inserts designed for the internal flow of refrigerant therethrough and/or the external flow of refrigerant thereover.

Abstract: A microchannel heat exchanger includes a plurality of microchannel tubes including a first set of microchannel tubes and a second set of microchannel tubes. A first circuit of the microchannel heat exchanger includes the first set of microchannel tubes, and a portion of a first fluid flows through the first set of microchannel tubes and exchanges heat with a second fluid. A second circuit of the microchannel heat exchanger includes the second set of microchannel tubes, and a reminder of the first fluid flows through the second set of microchannel tubes and exchanges heat with the second fluid. The first fluid from the first circuit and the first fluid from the second circuit combine into a common flow.

Abstract: In a parallel flow heat exchanger having an inlet manifold connected to an outlet manifold by a plurality of parallel channels, a spirally shaped insert is disposed within the refrigerant flow path in the inlet manifold such that a swirling motion is imparted to the refrigerant flow in the manifold so as to cause a more uniform distribution of refrigerant to the individual channels. Various embodiments of the spirally shaped inserts are provided, including inserts designed for the internal flow of refrigerant therethrough and/or the external flow of refrigerant thereover.

Abstract: In a parallel flow heat exchanger having an inlet manifold connected to an outlet manifold by a plurality of parallel channels, a spirally shaped insert is disposed within the refrigerant flow path in the inlet manifold such that a swirling motion is imparted to the refrigerant flow in the manifold so as to cause a more uniform distribution of refrigerant to the individual channels. Various embodiments of the spirally shaped inserts are provided, including inserts designed for the internal flow of refrigerant therethrough and/or the external flow of refrigerant thereover.

Abstract: A method is provided for mitigating two-phase refrigerant maldistribution in heat exchange channels of a parallel flow evaporator. An inlet manifold of the evaporator includes a first stage, at least one intermediate stage, and a final stage. Each stage includes an expansion chamber, a contraction chamber, and at least one heat exchange channel interconnecting the stage to an outlet manifold of the evaporator. The method includes throttling the two-phase refrigerant in the expansion chamber of each stage, flowing a portion of the throttled refrigerant through the at least one heat exchange channel to the outlet manifold, mixing and jetting the two-phase refrigerant in each contraction chamber to increase the velocity of the refrigerant, and passing the refrigerant out an exit of the outlet manifold.

Abstract: A comb-like insert having a body and plurality of tapered fingers is installed with its fingers disposed within respective minichannels. The fingers and their respective minichannels are so sized as to restrict the channels and frictionally hold the insert in place in one dimension while providing for gaps in another dimension such that the flow of refrigerant is somewhat obstructed but allowed to pass through the gaps between the insert fingers and the minichannel walls and then expand as it passes along the tapered fingers to thereby provide a more homogenous mixture to the individual minichannels. A provision is also made to hold the insert in its installed position by way of internal structure within the inlet manifold. In one embodiment, an internal plate is provided for that purpose, and the plate has openings formed therein for the equalization of pressure on either side thereof.

Abstract: A heat exchanger includes a first header and a second header and a plurality of heat exchange tubes extending therebetween. Each heat exchange tube has an inlet end opening to one of the headers and an outlet opening to the other header. Each heat exchange tube has a plurality of channels extending longitudinally in parallel relationship from its inlet end to its outlet end, each channel defining a discrete refrigerant flow path. The inlet end of each of the plurality of heat exchange tubes is positioned with the inlet opening to the channels disposed in spaced relationship with and facing an opposite inside surface of the header thereby defining a relatively narrow gap between the inlet opening to the channels and the facing opposite inside surface of the header. The gap may function either as a primary expansion device or as a secondary expansion device.

Abstract: A parallel flow (minichannel or microchannel) evaporator includes a porous member inserted at the entrance of the evaporator channels which provides refrigerant expansion and pressure drop controls resulting in the elimination of refrigerant maldistribution and prevention of potential compressor flooding.

Abstract: In a parallel flow heat exchanger, which is susceptible to having a non-uniform distribution of a two-phase refrigerant flow to the individual channels, the resultant differences in the refrigerant flow therethrough are compensated and counter-balanced by a corresponding difference in the external heat transfer rate for the respective channels. In one embodiment, these differences are accomplished by variable characteristics of extended heat transfer surface elements such as fin type, fin density, fin geometry and difference in construction materials, and in another embodiment, by varying the airflow distribution over the cross-section area of the heat exchanger.