Abstract: A multi-coil microchannel heat exchanger includes a first coil including a first inlet header, a first outlet header and first microchannel tubes; a second coil including a second inlet header, a second outlet header and second microchannel tubes; a first inlet connector fluidly connected to the first inlet header; a first outlet connector fluidly connected to the first outlet header; a second inlet connector fluidly connected to the second inlet header; and a second outlet connector fluidly connected to the second outlet header. The first coil and the second coil are arranged successively along the length direction of the multi-coil microchannel heat exchanger. The multi-coil microchannel heat exchanger includes a first side and a second side along the length direction, the first inlet connector, the first outlet connector, the second inlet connector and the second outlet connector are all located at the first side.

Abstract: A centrifugal fan for a heating, ventilation, air conditioning, and refrigeration (HVACR) system is disclosed. The centrifugal fan includes a volute housing having an inner surface and a curved inlet shroud. The volute housing defines an air outlet. The curved inlet shroud defines an air inlet. The air inlet has an inlet airflow cross-sectional area that lies substantially perpendicular to an outlet airflow cross-sectional area of the air outlet. The centrifugal fan also includes an impeller mounted for rotation about a rotational axis within the volute housing. The impeller has a plurality of fan blades. The plurality of fan blades has an outer surface. The centrifugal fan further includes a light source. The inner surface of the volute housing and the outer surface of the plurality of fan blades includes a photocatalyst layer. The light source is configured to emit light on the photocatalyst layer.

Abstract: A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a first compressor having a first capacity, a second compressor having a second capacity, a condenser, an expansion device, and an evaporator fluidly connected. The first compressor and the second compressor are arranged in parallel. The first compressor includes a first lubricant sump. The second compressor includes a second lubricant sump. The first lubricant sump is fluidly connected to the second lubricant sump via a lubricant transfer conduit. A flow restrictor is disposed in the lubricant transfer conduit. The flow restrictor is configured to reduce a refrigerant flow between the first compressor and the second compressor.

Abstract: Wind baffles are provided at a side discharge vent of a cabinet containing a heating, ventilation, air conditioning, and refrigeration (HVACR) system. The wind baffles include two or more baffles joined to a support frame. The baffles have a leading edge towards ambient environment surrounding of the cabinet and a trailing edge towards an interior of the cabinet, and the leading edge has a perimeter greater than a perimeter of the trailing edge. The baffles may surround each successive baffle. The baffles may be concentric The wind baffles may be located between ambient environment surrounding of the cabinet and a fan near the side discharge vent. The fan may be a variable-speed fan.

Abstract: A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a first compressor having a first capacity, a second compressor having a second capacity, a condenser, an expansion device, and an evaporator fluidly connected. The first compressor and the second compressor are arranged in parallel. The first compressor includes a first lubricant sump. The second compressor includes a second lubricant sump. The first lubricant sump is fluidly connected to the second lubricant sump via a lubricant transfer conduit. A flow restrictor is disposed in the lubricant transfer conduit. The flow restrictor is configured to reduce a refrigerant flow between the first compressor and the second compressor.

Abstract: An inward gas/liquid distribution structure used in microchannel heat exchangers is disclosed. The inward gas/liquid distribution structure can help optimizing refrigerant distribution for a microchannel heat exchanger with long distribution pipe or a microchannel heat exchanger having significant wind field differences. The inward gas/liquid distribution structure includes an inlet header component. The inlet header component has n inlets that are configured to allow gas/liquid to enter the inlet header component, and “n” is an integer that is greater than or equal to 2. The inward gas/liquid distribution structure also includes m distribution components. The m distribution components are located in the inlet header component and connected to the n inlets, respectively. In an example, the number m equals to the number n.

Abstract: Methods as disclosed herein are generally configured to help determine a pressure differential (or pressure head) in a fluid circulation system of for example, a HVAC system, for controlling the fluid circulation system. The method may include obtaining a correlation between a fluid flow rate and a pressure differential in the fluid circulation system by varying an operation speed of the pump. The method may also include obtaining a desired fluid flow rate for matching a cooling capacity of the HVAC system and determining a pressure differential setpoint corresponding to the desired fluid flow rate based on the correlation between the fluid flow rate and the pressure differential. The methods can be executed by, for example, a controller of the HVAC system so as to eliminate the requirement of a user to set up the pressure differential.

Abstract: A heat recovery system and methods of their use that include a liquid separator, which allows for relatively less refrigerant charge needed for operation of the heat recovery system, e.g. in a cooling and/or heat recovery mode. The liquid separator separates the liquid and vapor from fluid exiting the heat recovery exchanger, which can ensure that the inlet of the condenser coil is sourced with vapor and minimizes liquid entering the condenser coil. The liquid separator does not receive liquid refrigerant from the condenser coil, such as in a regular operating mode (e.g. cooling and/or heat recovery mode). Use of the liquid separator and its arrangement within the fluid circuit can thereby reduce the operating refrigerant charge needed for the system. A flow control device can control the heat recovery and/or cooling capacity of the heat recovery system.

Abstract: A heater, e.g. an anti-freezing heater, is disclosed. The heater can be configured to set off an alarm when a heating element is broken or malfunctioning. The heater can also be configured to connect the heating element to a relatively low voltage when the heating element may experience a dry burning condition.

Abstract: Methods, systems, and apparatuses are described to help manage oil return such as in a chiller system of a HVAC system. A refrigerant/oil mixture can be directed out of the evaporator into an oil return heat exchanger that is configured to help vaporize a refrigerant portion of the refrigerant/oil mixture. Superheat refrigerant vapor can be directed from a condenser into the oil return heat exchanger as the heat energy to vaporize the refrigerant portion in the refrigerant/oil mixture. The oil return heat exchanger can be positioned lower than the evaporator so that gravity can help the refrigerant/oil mixture to flow into the oil return heat exchanger.

Abstract: A mounting clip that can be used to mount a heat exchanger to a housing, for example, in a HVAC system is disclosed. The mounting clip may include a receiver portion configured to receive, for example, an end portion of the heat exchanger. The mounting clip may also include a clip portion configured to secure the mounting clip to the housing. The mounting clip can be used to mount the heat exchanger to the housing relatively easily, reducing the manufacturing cost and time of the HVAC system.

Abstract: A fixing device includes a gasket and a clip. The clip includes a clip upper portion, a clip body portion, and a clip leg portion. The clip upper portion has a width wider than the clip body portion and the clip leg portion. The clip upper portion, the clip body portion, and the clip leg portion are connected to form an open loop facing downward. The gasket includes a gasket upper portion, a gasket intermediate portion, and a gasket base portion forming an “A” shape. The gasket is compressible. The clip upper portion and the clip body portion define two receiving areas evenly distributed at two inner sides of the clip. The gasket is evenly and simultaneously compressed toward the two receiving areas of the clip while the clip moves downward without tilting or slanting.

Abstract: A valve cap (14) can be configured to have an integral sealing member (50) at least part of which is extendable into an opening(18) of a valve body (12) and seals against an inner surface of a valve body wall (16). The sealing member (50) is configured to have a void space (51) such that when fluid leaks from a valve stem disposed in the valve body (12), an internal pressure in the void space forces a surface of the sealing member (50) against the inner surface of the valve body wall (16), thereby tightening a seal between the sealing member (50) and the valve body wall (16). In such circumstances, the fluid is prevented effectively from exiting the valve cap (14).

Abstract: Methods, systems, and apparatuses are described to help manage oil return such as in a chiller system of a HVAC system. A refrigerant/oil mixture can be directed out of the evaporator into an oil return heat exchanger that is configured to help vaporize a refrigerant portion of the refrigerant/oil mixture. Superheat refrigerant vapor can be directed from a condenser into the oil return heat exchanger as the heat energy to vaporize the refrigerant portion in the refrigerant/oil mixture. The oil return heat exchanger can be positioned lower than the evaporator so that gravity can help the refrigerant/oil mixture to flow into the oil return heat exchanger.