Abstract: A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes an array of packaged units; and a controller to obtain an operating condition of the array of packaged units, derive the operating condition to construct an operating pattern, select one or more packaged units to be adjusted to increase efficiency of the array of packaged units based on the operating pattern, and to adjust operation of the one or more packaged units selected by the controller.

Abstract: Apparatuses, systems and methods are directed to heat exchangers that are made of microchannel tubes and that have offset fins of various geometries and density. The heat exchanger coils can be implemented in various refrigeration and/or heating, ventilation, and air conditioning (HVAC) units or systems thereof.

Abstract: A refrigeration unit and methods of operating a refrigeration unit for an HVACR system are disclosed. The refrigeration unit includes a refrigerant circuit, including a compressor, a condenser, an expansion device, and an evaporator fluidly connected. The condenser includes a condenser portion and a subcooler portion. A single receiver tank is fluidly connected to an output of the condenser portion and an input of the subcooler portion. A restrictor is fluidly connected to the receiver tank. The restrictor can induce a pressure drop in a working fluid flowing from the subcooler portion.

Abstract: Embodiments of a heat exchanger, e.g. a micro-channel heat exchanger are disclosed. The heat exchanger may include a plurality of rows of micro-channel tubes, each of which can be configured to direct a working fluid in a specific direction. The heat exchanger may include one or more distributors in a distribution header of the heat exchanger, each of which can be connected to a different application circuit (e.g. a refrigeration circuit) so that a capacity of the heat exchanger may be regulated. The heat exchanger as disclosed herein can be used as an evaporator and/or a condenser in a refrigeration system.

Abstract: To continue operating a compression refrigerant system even while the system's brazed plate heat exchanger contains, in localized areas, water at or below its atmospheric subfreezing water temperature, a penetrating temperature probe senses the water temperature at a strategic intermediate point between the heat exchanger's water inlet and outlet. The brazed plate heat exchanger comprises a series of corrugated plates stacked and brazed together to create an alternating arrangement of water and refrigerant passages in heat transfer relationship with each other. In some examples, the idea is to take advantage of the principle that water has a lower freezing temperature at relatively high pressure and that the relatively small micro-channel passages of intermediate water passages within the brazed plate heat exchanger can withstand appreciably higher pressure than other areas within the heat exchanger, such as the areas at the heat exchanger's water inlet and water outlet.

Abstract: A refrigeration unit and methods of operating a refrigeration unit for an HVACR system are disclosed. The refrigeration unit includes a refrigerant circuit, including a compressor, a condenser, an expansion device, and an evaporator fluidly connected. The condenser includes a condenser portion and a subcooler portion. A single receiver tank is fluidly connected to an output of the condenser portion and an input of the subcooler portion. A restrictor is fluidly connected to the receiver tank. The restrictor can induce a pressure drop in a working fluid flowing from the subcooler portion.

Abstract: Apparatuses, systems and methods are directed to heat exchangers that are made of microchannel tubes and that have offset fins of various geometries and density. The heat exchanger coils can be implemented in various refrigeration and/or heating, ventilation, and air conditioning (HVAC) units or systems thereof.

Abstract: To continue operating a compression refrigerant system even while the system's brazed plate heat exchanger contains, in localized areas, water at or below its atmospheric subfreezing water temperature, a penetrating temperature probe senses the water temperature at a strategic intermediate point between the heat exchanger's water inlet and outlet. The brazed plate heat exchanger comprises a series of corrugated plates stacked and brazed together to create an alternating arrangement of water and refrigerant passages in heat transfer relationship with each other. In some examples, the idea is to take advantage of the principle that water has a lower freezing temperature at relatively high pressure and that the relatively small micro-channel passages of intermediate water passages within the brazed plate heat exchanger can withstand appreciably higher pressure than other areas within the heat exchanger, such as the areas at the heat exchanger's water inlet and water outlet.

Abstract: A penetrating temperature probe senses the water temperature of a brazed plate heat exchanger at a particularly cold intermediate point between the heat exchanger's water inlet and outlet. The brazed plate heat exchanger has a series of corrugated plates stacked and brazed together to create an alternating arrangement of water and refrigerant passages in heat transfer relationship with each other.

Abstract: Embodiments of a heat exchanger, e.g. a micro-channel heat exchanger are disclosed. The heat exchanger may include a plurality of rows of micro-channel tubes, each of which can be configured to direct a working fluid in a specific direction. The heat exchanger may include one or more distributors in a distribution header of the heat exchanger, each of which can be connected to a different application circuit (e.g. a refrigeration circuit) so that a capacity of the heat exchanger may be regulated. The heat exchanger as disclosed herein can be used as an evaporator and/or a condenser in a refrigeration system.

Abstract: A chiller system including an evaporator for evaporating a refrigerant and a water pipe in fluid communication with the evaporator. The water pipe is configured to allow water to pass through at a flow rate and to circulate the water with the evaporator to exchange heat with the refrigerant in the evaporator. The chiller system includes a flow restrictor tube within the water pipe that is configured to allow the water to flow through the flow restrictor tube at a reduced flow rate relative to the flow rate. The chiller system also includes a measuring probe that passes through walls of the water pipe and the flow restrictor tube and includes an accuracy range of flow rates less than the flow rate. The measuring probe is configured to measure the reduced flow rate within the flow restrictor tube where the reduced flow rate is within the accuracy range.

Abstract: A heat pump includes a valve system that connects a receiver tank in fluid communication with an indoor heat exchanger, wherein the valve system, operating under a novel control scheme, works in conjunction with the receiver to control the heat pump's effective refrigerant charge. To avoid suction or discharge pressure faults and to help prevent slugs of liquid refrigerant from entering the heat pump's compressor as the heat pump switches between heating and cooling modes or switches between heating and defrost modes, the control scheme provides momentary periods of transition between those modes of operation. In some embodiments, the valve system comprises a check valve connected in parallel flow relationship with a two-position receiver valve, wherein the check valve has an appreciably higher flow coefficient than that of the receiver valve.

Abstract: To continue operating a compression refrigerant system even while the system's brazed plate heat exchanger contains, in localized areas, water at or below its atmospheric subfreezing water temperature, a penetrating temperature probe senses the water temperature at a strategic intermediate point between the heat exchanger's water inlet and outlet. The brazed plate heat exchanger comprises a series of corrugated plates stacked and brazed together to create an alternating arrangement of water and refrigerant passages in heat transfer relationship with each other. In some examples, the idea is to take advantage of the principle that water has a lower freezing temperature at relatively high pressure and that the relatively small micro-channel passages of intermediate water passages within the brazed plate heat exchanger can withstand appreciably higher pressure than other areas within the heat exchanger, such as the areas at the heat exchanger's water inlet and water outlet.

Abstract: A chiller system including an evaporator for evaporating a refrigerant and a water pipe in fluid communication with the evaporator. The water pipe is configured to allow water to pass through at a flow rate and to circulate the water with the evaporator to exchange heat with the refrigerant in the evaporator. The chiller system includes a flow restrictor tube within the water pipe that is configured to allow the water to flow through the flow restrictor tube at a reduced flow rate relative to the flow rate. The chiller system also includes a measuring probe that passes through walls of the water pipe and the flow restrictor tube and includes an accuracy range of flow rates less than the flow rate. The measuring probe is configured to measure the reduced flow rate within the flow restrictor tube where the reduced flow rate is within the accuracy range.

Abstract: A reversible HVAC heating/cooling refrigerant system includes a novel valve system that allows an outdoor heat exchanger to function as a subcooler during a cooling or defrost mode and function as a receiver tank for storing excess liquid refrigerant during a heating mode. In the heating mode, a cooling expansion valve is kept slightly open to flood the subcooler with liquid refrigerant while a heating expansion valve is regulated to maintain a desired level of superheat at the suction side of the refrigerant system's compressor. The novel valve system also serves as a pressure relief valve to protect the subcooler from excess pressure caused by thermal expansion of liquid refrigerant trapped within the subcooler.

Abstract: A heat pump includes a valve system that connects a receiver tank in fluid communication with an indoor heat exchanger, wherein the valve system, operating under a novel control scheme, works in conjunction with the receiver to control the heat pump's effective refrigerant charge. To avoid suction or discharge pressure faults and to help prevent slugs of liquid refrigerant from entering the heat pump's compressor as the heat pump switches between heating and cooling modes or switches between heating and defrost modes, the control scheme provides momentary periods of transition between those modes of operation. In some embodiments, the valve system comprises a check valve connected in parallel flow relationship with a two-position receiver valve, wherein the check valve has an appreciably higher flow coefficient than that of the receiver valve.

Abstract: A medical device having an elongate flexible tube extending between a proximal end and a a distal end. The device has a lumen extending between the proximal and distal ends. The lumen contains therapeutic cells and is sized to receive a plunger. The plunger is movable through at least a portion of the lumen. The device further includes an actuator at the proximal end of the elongate flexible tube, and a delivery member at the distal end of the elongate flexible tube.

Abstract: A heat exchanger comprising a first coil assembly including an inlet manifold; an outlet manifold parallel to and spaced from the inlet manifold; and a plurality of tubes each operably connected to and linking the inlet and the outlet manifolds, each tube having a multiplicity of flow paths and a hydraulic diameter in the range of 0.05 0.08≦to HD≦0.30.

Abstract: A test circuit (15 or 65), comprised of a plurality of parallel-connected circuit modules (15.sub.o-n or 65.sub.o-n), in response to both control signals from an associated commercially available automated test set (12), and output data from a test set-accessed read/write memory (14) under test, continuously senses for the presence of valid "one" or "zero" outputs on the data bit lines of the memory throughout a test set-established time window test period. When the memory output from a given data bit line, as applied to only an associated one of the circuit modules, is determined, as normally expected, to be continuously valid during each successive time window test period, a "pass" RESULT signal is generated by that circuit module and continuously applied to the test circuit (12) for flagging at any time between termination of the time window and the end of a given test set-established memory read cycle. Conversely, should the output on any memory data bit line be determined to be invalid (i.e.

Abstract: A method for preparing ceramic material from a polymer which comprises selecting a polymer from the class consisting of poly(diorganosilanes), poly(haloorganosilanes), poly(carbosilanes), polysilazanes, polycarbocarboranes, and polyborazines; heating said polymer to a temperature from 700.degree. to 2000.degree. C at a rate of at most 100.degree. C/hr. in an inert atmosphere for at least one hour; and cooling to room temperature at a cooling rate which avoids thermal stresses.