Abstract: A method of initiating a low-energy cooling mode using a controller of an HVAC system includes measuring a temperature of ambient air proximal to a condenser coil and determining whether the temperature of the ambient air proximal the condenser coil is less than a temperature threshold. If the temperature of the ambient air is less than the temperature threshold, the HVAC system is configured to operate in a low-energy cooling mode. In the low-energy cooling mode, the controller opens a first bypass valve to allow a refrigerant to bypass a compressor and the compressor is powered off. The HVAC system is operated until a cooling demand has been met.

Abstract: A method of initiating a low-energy cooling mode using a controller of an HVAC system includes measuring a temperature of ambient air proximal to a condenser coil and determining whether the temperature of the ambient air proximal the condenser coil is less than a temperature threshold. If the temperature of the ambient air is less than the temperature threshold, the HVAC system is configured to operate in a low-energy cooling mode. In the low-energy cooling mode, the controller opens a first bypass valve to allow a refrigerant to bypass a compressor and the compressor is powered off. The HVAC system is operated until a cooling demand has been met.

Abstract: A method of initiating a low-energy cooling mode using a controller of an HVAC system includes measuring a temperature of ambient air proximal to a condenser coil and determining whether the temperature of the ambient air proximal the condenser coil is less than a temperature threshold. If the temperature of the ambient air is less than the temperature threshold, the HVAC system is configured to operate in a low-energy cooling mode. In the low-energy cooling mode, the controller opens a first bypass valve to allow a refrigerant to bypass a compressor and the compressor is powered off. The HVAC system is operated until a cooling demand has been met.

Abstract: A heat exchanger includes a plurality of conduits that extend between a first endplate and a second endplate. A first manifold is coupled to the first endplate to couple the first manifold to first ends of the plurality of conduits. An inlet is coupled to the first manifold to direct a first fluid into the first manifold and at least one baffle is disposed within the first manifold to form a first cavity and a second cavity. The at least one baffle of the first manifold is configured to direct the first fluid from the inlet to a first conduit of the plurality of conduits. A second manifold is coupled to the second endplate to couple the second manifold to second ends of the plurality of conduits and at least one baffle is disposed within the second manifold to form a fourth cavity and a fifth cavity.

Abstract: A stub pipe housing and a method for installing a stub pipe housing in a heating, ventilation, and air conditioning (“HVAC”) system, the stub pipe housing comprising a first end for sealed contact with an external surface of a cabinet in the HVAC system and a non-permeable material extending to a second end for sealed contact with an external pipe. Sealed contact between the first end and the cabinet, sealed contact between the second end and the external surface, and the non-permeable material ensures any fluid escaping the connection between the stub pipe and the external pipe is directed to the cabinet. The stub pipe housing supports the connection using resilient material, rigid material with compliant seals or some combination. Fluids are directed to flow through the stub pipe opening in the cabinet or directed to flow through other openings.

Abstract: A refrigerant detector testing system according to aspects of the disclosure includes a metering orifice formed in a suction line that is disposed between an evaporator coil and a compressor, a valve fluidly coupled to the metering orifice, a connecting tube fluidly coupled to the valve on a side opposite the metering orifice, a mixing device having an input orifice fluidly coupled to the connecting tube. In some embodiments, the mixing device includes an air intake disposed proximate the input orifice, a throttling portion downstream of the input orifice and the air intake, the throttling portion having a reduced cross-sectional area, and a diffuser section positioned downstream of the throttling portion, the diffuser section having an output orifice. According to aspects of the disclosure, a refrigerant detector fluidly exposed to the output orifice.

Abstract: A system includes a first heat exchanger, a flash tank, a first compressor, a condenser, a second heat exchanger, and a second compressor. The first heat exchanger removes heat from carbon dioxide refrigerant. The flash tank stores the carbon dioxide refrigerant from the first heat exchanger. The first compressor compresses the carbon dioxide refrigerant and sends the compressed carbon dioxide refrigerant to the first heat exchanger. The condenser removes heat from a second refrigerant. The second heat exchanger receives the second refrigerant from the condenser. The second heat exchanger further removes heat from the carbon dioxide refrigerant stored in the flash tank. The second compressor compresses the second refrigerant from the heat exchanger. The second compressor sends the second refrigerant to the condenser.

Abstract: A subcooling controller includes a sensor and a processor. The sensor measures one or more of a temperature external to a first heat exchanger that removes heat from carbon dioxide refrigerant, a temperature of the carbon dioxide refrigerant, and a pressure of the carbon dioxide refrigerant. The processor determines that one or more of the measured temperature external to the first heat exchanger, the temperature of the carbon dioxide refrigerant, and the pressure of the carbon dioxide refrigerant is above a threshold and in response to that determination, activates a subcooling system. The subcooling system includes a condenser, a second heat exchanger, and a compressor. The condenser removes heat from a second refrigerant. The second heat removes heat from the carbon dioxide refrigerant stored in a flash tank. The compressor compresses the second refrigerant from the second heat exchanger and sends the second refrigerant to the condenser.

Abstract: A subcooling controller includes a sensor and a processor. The sensor measures one or more of a temperature external to a first heat exchanger that removes heat from carbon dioxide refrigerant, a temperature of the carbon dioxide refrigerant, and a pressure of the carbon dioxide refrigerant. The processor determines that one or more of the measured temperature external to the first heat exchanger, the temperature of the carbon dioxide refrigerant, and the pressure of the carbon dioxide refrigerant is above a threshold and in response to that determination, activates a subcooling system. The subcooling system includes a condenser, a second heat exchanger, and a compressor. The condenser removes heat from a second refrigerant. The second heat removes heat from the carbon dioxide refrigerant stored in a flash tank. The compressor compresses the second refrigerant from the second heat exchanger and sends the second refrigerant to the condenser.

Abstract: An apparatus that includes a refrigeration circuit that includes an evaporator, a first condenser and a compressor. The apparatus includes a refrigerant-water heat exchanger that includes a second condenser fluidly coupled to the refrigeration circuit. A control valve is operatively connected to the refrigeration circuit to direct flow of refrigerant through at least one of the first condenser during a dehumidification mode and the second condenser during a water heating mode. A damper is disposed on an upwind side of the evaporator, the damper being operable to reduce airflow across the evaporator during a ventilation mode.

Abstract: A stub pipe housing and a method for installing a stub pipe housing in a heating, ventilation, and air conditioning (“HVAC”) system, the stub pipe housing comprising a first end for sealed contact with an external surface of a cabinet in the HVAC system and a non-permeable material extending to a second end for sealed contact with an external pipe. Sealed contact between the first end and the cabinet, sealed contact between the second end and the external surface, and the non-permeable material ensures any fluid escaping the connection between the stub pipe and the external pipe is directed to the cabinet. The stub pipe housing supports the connection using resilient material, rigid material with compliant seals or some combination. Fluids are directed to flow through the stub pipe opening in the cabinet or directed to flow through other openings.

Abstract: A method of protecting a single-stage furnace in a multi-zone system includes monitoring a temperature of each zone of a plurality of zones, determining if the temperature of at least one zone of the plurality of zones is less than a threshold temperature, powering on the HVAC system to satisfy a heating demand of the zone having a temperature less than the threshold temperature, monitoring an outlet temperature of the single-stage furnace, determining if the outlet temperature is greater than an outlet temperature threshold, and responsive to a determination that the outlet temperature is greater than the outlet temperature threshold, modulating a gas valve to reduce a flow of gas to the single-stage furnace.

Abstract: A refrigerant detector testing system according to aspects of the disclosure includes a metering orifice formed in a suction line that is disposed between an evaporator coil and a compressor, a valve fluidly coupled to the metering orifice, a connecting tube fluidly coupled to the valve on a side opposite the metering orifice, a mixing device having an input orifice fluidly coupled to the connecting tube. In some embodiments, the mixing device includes an air intake disposed proximate the input orifice, a throttling portion downstream of the input orifice and the air intake, the throttling portion having a reduced cross-sectional area, and a diffuser section positioned downstream of the throttling portion, the diffuser section having an output orifice. According to aspects of the disclosure, a refrigerant detector fluidly exposed to the output orifice.

Abstract: A heat exchanger includes a plurality of conduits that extend between a first endplate and a second endplate. A first manifold is coupled to the first endplate to couple the first manifold to first ends of the plurality of conduits. An inlet is coupled to the first manifold to direct a first fluid into the first manifold and at least one baffle is disposed within the first manifold to form a first cavity and a second cavity. The at least one baffle of the first manifold is configured to direct the first fluid from the inlet to a first conduit of the plurality of conduits. A second manifold is coupled to the second endplate to couple the second manifold to second ends of the plurality of conduits and at least one baffle is disposed within the second manifold to form a fourth cavity and a fifth cavity.

Abstract: An apparatus that includes a refrigeration circuit that includes an evaporator, a first condenser and a compressor. The apparatus includes a refrigerant-water heat exchanger that includes a second condenser fluidly coupled to the refrigeration circuit. A control valve is operatively connected to the refrigeration circuit to direct flow of refrigerant through at least one of the first condenser during a dehumidification mode and the second condenser during a water heating mode. A damper is disposed on an upwind side of the evaporator, the damper being operable to reduce airflow across the evaporator during a ventilation mode.

Abstract: A method of initiating a low-energy cooling mode using a controller of an HVAC system includes measuring a temperature of ambient air proximal to a condenser coil and determining whether the temperature of the ambient air proximal the condenser coil is less than a temperature threshold. If the temperature of the ambient air is less than the temperature threshold, the HVAC system is configured to operate in a low-energy cooling mode. In the low-energy cooling mode, the controller opens a first bypass valve to allow a refrigerant to bypass a compressor and the compressor is powered off. The HVAC system is operated until a cooling demand has been met.

Abstract: A refrigerant detector testing system according to aspects of the disclosure includes a metering orifice formed in a suction line that is disposed between an evaporator coil and a compressor, a valve fluidly coupled to the metering orifice, a connecting tube fluidly coupled to the valve on a side opposite the metering orifice, a mixing device having an input orifice fluidly coupled to the connecting tube. In some embodiments, the mixing device includes an air intake disposed proximate the input orifice, a throttling portion downstream of the input orifice and the air intake, the throttling portion having a reduced cross-sectional area, and a diffuser section positioned downstream of the throttling portion, the diffuser section having an output orifice. According to aspects of the disclosure, a refrigerant detector fluidly exposed to the output orifice.

Abstract: A system comprising a furnace, an impeller, and a controller. The impeller directs air into an environment through the furnace. The controller receives calls to heat the environment or circulate air in the environment. In response to receiving a call to heat the environment, the controller activates the furnace and the impeller such that the impeller draws a first amount of power and turns in a first direction causing air to be impelled from the impeller through the furnace into the environment. In response to receiving a call to circulate air in the environment, the controller activates the impeller such that the impeller draws a second amount of power and turns in a second direction causing air to be impelled from the impeller into the environment, wherein the second amount of power is less than the first amount of power and the second direction is opposite the first direction.

Abstract: An apparatus that includes a refrigeration circuit that includes an evaporator, a first condenser and a compressor. The apparatus includes a refrigerant-water heat exchanger that includes a second condenser fluidly coupled to the refrigeration circuit. A control valve is operatively connected to the refrigeration circuit to direct flow of refrigerant through at least one of the first condenser during a dehumidification mode and the second condenser during a water heating mode. A damper is disposed on an upwind side of the evaporator, the damper being operable to reduce airflow across the evaporator during a ventilation mode.

Abstract: A heat exchanger includes a plurality of conduits that extend between a first endplate and a second endplate. A first manifold is coupled to the first endplate to couple the first manifold to first ends of the plurality of conduits. An inlet is coupled to the first manifold to direct a first fluid into the first manifold and at least one baffle is disposed within the first manifold to form a first cavity and a second cavity. The at least one baffle of the first manifold is configured to direct the first fluid from the inlet to a first conduit of the plurality of conduits. A second manifold is coupled to the second endplate to couple the second manifold to second ends of the plurality of conduits and at least one baffle is disposed within the second manifold to form a fourth cavity and a fifth cavity.