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.