Abstract: The present disclosure relates to a HVAC system operable to use a refrigerant in a refrigerant circuit to heat or cool an indoor space and includes a defrost circuit connected to the refrigerant circuit. The defrost circuit includes a first three-way valve, a defrost line, a defrost passage in an outdoor heat exchanger, and a defrost return line. When the HVAC system is in a defrost mode, a four-way valve is operable to direct the refrigerant flow in a second direction through the outdoor heat exchanger. The first three-way valve is operable to divert some or all of the refrigerant from the refrigerant circuit and through the defrost circuit to defrost the outdoor heat exchanger. The defrost return line returns the diverted refrigerant to the refrigerant circuit upstream of an expansion device and downstream of the indoor heat exchange with respect to the second direction.

Abstract: A furnace assembly is disclosed that includes an intake manifold connectable to a fuel supply, a partition panel, and a burner assembly mountable to the partition panel and operable to combust a pre-mixed fuel and air mixture to produce a heated flue gas. The burner assembly includes burners configured to combust of the mixture into a flue gas. The burner assembly also includes a heat shielding plate located and shaped to reduce heat communicated to the partition panel due to the combustion. The heat shielding plate is manufactured using a high-temperature alloy and includes holes, each hole aligned with one of the burners. A groove in the plate accommodates thermal expansion of and reduces thermal deformation of the plate. A heat exchanger is mounted to the partition panel in thermal communication with the burners that includes tubes positioned to receive the heated flue gas.

Abstract: Contemporaneous hybrid heating may be provided by a heat pump, including: an indoor heat exchanger located in or in communication with the conditioned environment; an outdoor heat exchanger located in or in communication with the outdoor environment, wherein the outdoor heat exchanger is in fluid communication with the indoor heat exchanger via a refrigerant circuit; a fueled heater; and a controller, configured to, when the system is operating in a hybrid heating mode, activate both of the heat pump and the fueled heater at a given time based on an air rise temperature measured across the indoor heat exchanger.

Abstract: Cascaded Cold Climate Heat Pump systems (“CCCHP”) and methods are disclosed. A CCCHP provides efficiency improvements over traditional heat pump systems by utilizing a connected cascaded circuit configuration, to apportion compressor load of a heat pump circuit between two or more circuits. One embodiment that allows the CCCHP to achieve this efficiency improvement includes connecting multiple cold climate heat pump circuits through an intermediary heat exchange unit in a cascaded configuration, where energy is displaced from one refrigerant flow of a circuit into the refrigerant flow of another circuit. This allows each circuit to deploy a smaller compressor that operates within a narrower pressure and temperature range, than it otherwise would if it utilized a single larger compressor in a single circuit operating within a larger pressure range, which has a larger pressure differential between its initial state and its desired state causing inefficiency in the system.

Abstract: A tie band with various locking methods is disclosed. The tie band can include a head and a band extending from the head. The head includes a first flange, a second flange, and a connector connecting the first flange and the second flange. The connector defines a hole in the head. The band includes two elongate faces, two side faces, and protrusions extending from the side faces. In some aspects, the band is fusible to the head by applying heat to the head, at least one of the protrusions, or a combination thereof when the portion of the band is inserted through the hole.

Abstract: A heating, ventilation, and air conditioning (HVAC) system and controller therefor to operate with thermal energy reservoirs is provided to set a four-way valve to route a refrigerant through a refrigerant circuit in a first direction when the HVAC system is set to a cooling mode or in a second direction, opposite to the first direction, when the HVAC system is set to a heating mode; and set bypass valves in the refrigerant circuit based on a temperature of a temperature holding material in a thermal energy reservoir and which of the heating mode and the cooling mode the four-way valve is set to, wherein the bypass valves route the refrigerant through the thermal energy reservoir to transfer thermal energy between the refrigerant and the temperature holding material.

Abstract: A furnace assembly has a fuel gas manifold connectable to a fuel gas supply that has fuel gas nozzles connectable to inshot burners. Each burner fires a flame and includes an air entrance section and a static air mixer including vanes with the mixer configured to fully mix the flow of fuel gas and the flow of ambient air flowing through the mixer into a fully mixed mixture. Each burner also includes a metal fiber mesh burner surface defines a surface where combustion of the fully mixed mixture occurs to create the flame. The furnace assembly also includes a heat exchanger in communication with the inshot burners and comprising tubes and a blower downstream of the heat exchanger and in fluid communication with the tubes and operable to create a negative pressure in the heat exchanger and pull the flows of fuel gas and ambient air into the burners.

Abstract: A heating, ventilation, and air-conditioning system with a refrigeration circuit that includes a compressor fluidly, an outdoor heat exchanger fluidly connected downstream of the compressor, a cooling expansion valve fluidly connected downstream of the outdoor heat exchanger, an indoor heat exchanger fluidly connected downstream of the cooling expansion valve when operating in a cooling mode. A bypass line fluidly connects the circuit from a first location downstream of the outdoor heat exchanger and upstream of the cooling expansion valve to a second location downstream of the indoor heat exchanger and upstream of the compressor. Some of the refrigerant is flowable through the bypass line at the first location to bypass the cooling expansion valve and the indoor heat exchanger and recombinable with the refrigerant in the circuit at the second location to lower the compressor discharge temperature compared to not flowing the refrigerant through the first bypass line.

Abstract: Cascaded Cold Climate Heat Pump systems (“CCCHP”) and methods are disclosed. A CCCHP provides efficiency improvements over traditional heat pump systems by utilizing a connected cascaded circuit configuration, to apportion compressor load of a heat pump circuit between two or more circuits. One embodiment that allows the CCCHP to achieve this efficiency improvement includes connecting multiple cold climate heat pump circuits through an intermediary heat exchange unit in a cascaded configuration, where energy is displaced from one refrigerant flow of a circuit into the refrigerant flow of another circuit. This allows each circuit to deploy a smaller compressor that operates within a narrower pressure and temperature range, than it otherwise would if it utilized a single larger compressor in a single circuit operating within a larger pressure range, which has a larger pressure differential between its initial state and its desired state causing inefficiency in the system.

Abstract: A tie band with various locking methods is disclosed. The tie band can include a head and a band extending from the head. The head includes a first flange, a second flange, and a connector connecting the first flange and the second flange. The connector defines a hole in the head. The band includes two elongate faces, two side faces, and protrusions extending from the side faces. In some aspects, the band is fusible to the head by applying heat to the head, at least one of the protrusions, or a combination thereof when the portion of the band is inserted through the hole.

Abstract: The present disclosure relates to a heat pump heating, ventilation, and air conditioning (heat pump HVAC) system, and more particularly to a system operable to use a refrigerant to heat or cool an indoor space with a refrigerant circuit performing a reversible vapor compression cycle between an outdoor heat exchanger and an indoor heat exchanger. The heat pump HVAC system includes an ejector in fluid communication with the refrigerant circuit. The refrigerant circuit includes a first flow of refrigerant upstream from the outdoor heat exchanger and a second flow of refrigerant downstream from the outdoor heat exchanger; and the ejector is configurable to combine the first flow and the second flow into a combined flow, at least a portion of which is returned to the compressor.

Abstract: A flame penetration resistant flexible duct and related devices and methods are disclosed. The flexible duct can include a tubular core, a vapor barrier, and an insulation assembly. The tubular core is configured to convey a fluid. The vapor barrier surrounds the tubular core. The insulation assembly is positioned between the tubular core and the vapor barrier. Further, the insulation assembly can include an insulation layer and a scrim layer bonded to the insulation layer. The scrim layer is configured to resist flame penetration of the flexible duct.

Abstract: The present disclosure relates to a HVAC system operable to use a refrigerant in a refrigerant circuit to heat or cool an indoor space and includes a defrost circuit connected to the refrigerant circuit. The defrost circuit includes a first three-way valve, a defrost line, a defrost passage in an outdoor heat exchanger, and a defrost return line. When the HVAC system is in a defrost mode, a four-way valve is operable to direct the refrigerant flow in a second direction through the outdoor heat exchanger. The first three-way valve is operable to divert some or all of the refrigerant from the refrigerant circuit and through the defrost circuit to defrost the outdoor heat exchanger. The defrost return line returns the diverted refrigerant to the refrigerant circuit upstream of an expansion device and downstream of the indoor heat exchange with respect to the second direction.