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: An HVAC system having a fixed orifice expansion device coupled to an evaporator coil is provided. In one embodiment, an expansion device coupled to an evaporator coil includes a flow restrictor and an evaporator inlet manifold. The flow restrictor includes multiple fixed orifices aligned with the refrigerant distribution tubes to restrict flow of refrigerant from the evaporator inlet manifold into the refrigerant distribution tubes through the multiple fixed orifices. Additional systems, devices, and methods are also disclosed.

Abstract: A heating, ventilation, and air-conditioning (“HVAC”) system for use with a refrigerant. The HVAC system includes a compressor, a condenser, an expansion device, an evaporator, and a separator. The compressor is operable to compress the refrigerant. The condenser is positioned downstream of the compressor and operable to condense the refrigerant. The expansion device is positioned downstream of the condenser and operable to reduce a pressure of the refrigerant flowing therethrough. The evaporator is positioned downstream of the expansion device and operable to vaporize the refrigerant from the expansion device. The separator is positioned downstream of the expansion device and operable to separate the refrigerant into liquid refrigerant and gaseous refrigerant. The gaseous refrigerant from the separator and the liquid refrigerant from the separator are combined prior to being compressed by the compressor.

Abstract: The present disclosure relates to a heating, ventilation, and air conditioning (“HVAC”) system include a supply damper, a return damper, and a defrost damper which are operable to control a supply airflow, a return airflow, and a defrost airflow to flow between a supply duct, a return duct, and an indoor heat exchanger without substantially flowing into and substantially cooling an indoor space. A reheat coil may also warm the supply air flow and a defrost return line may be used to bypass a bi-flow expansion device and an indoor heat exchanger.

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 heating, ventilation, and air conditioning (HVAC) system and controller therefor to operate with thermal energy reservoirs are 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 multiple tube bank heat exchanger includes a first tube bank including at least a first and a second flattened tube segments extending longitudinally in spaced parallel relationship and a second tube bank including at least a first and a second flattened tube segments extending longitudinally in spaced parallel relationship. The second tube bank is disposed behind the first tube bank with a leading edge of the second tube bank spaced from a trailing edge of the first tube bank. A continuous folded fin extends between the first and second flattened tube segments of both of said first tube bank and said second tube bank.

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 heating, ventilation, and air-conditioning (“HVAC”) system for use with a refrigerant. The HVAC system includes a compressor, a condenser, an expansion device, an evaporator, and a separator. The compressor is operable to compress the refrigerant. The condenser is positioned downstream of the compressor and operable to condense the refrigerant. The expansion device is positioned downstream of the condenser and operable to reduce a pressure of the refrigerant flowing therethrough. The evaporator is positioned downstream of the expansion device and operable to vaporize the refrigerant from the expansion device. The separator is positioned downstream of the expansion device and operable to separate the refrigerant into liquid refrigerant and gaseous refrigerant. The gaseous refrigerant from the separator and the liquid refrigerant from the separator are combined prior to being compressed by the compressor.

Abstract: A heat exchanger is provided including a first header and a second header and a plurality of heat exchange tube arranged in spaced parallel relationship and fluidly coupling the first and second header. A flow restricting element defining a first volume and a second volume is positioned within one of the first and second header. The heat exchanger has a multi-pass configuration such that a first portion of the plurality of heat exchange tubes are coupled to the first volume and form a first fluid pass of the heat exchanger and a second portion of the plurality of heat exchange tubes are coupled to the second volume and form a second fluid pass of the heat exchanger. During operation, the heat transfer fluid conveyed through the first volume has a first saturation temperature and the heat transfer fluid conveyed through the second volume has a different second saturation temperature.

Abstract: An HVAC system for use with a first refrigerant and a second refrigerant. The HVAC system may include a first refrigerant circuit for use with the first refrigerant, a second refrigerant circuit for use with the second refrigerant, and a heat exchanger. The first refrigerant circuit and the second refrigerant circuit may each include may include a compressor, an expansion device, and an evaporator. The compressor may include a first upper section, a first lower section, a second upper section in fluid communication with the first lower section, and a second lower section in fluid communication with the first upper section. The first upper section, the first lower section, the second upper section, and the second lower section may be arranged such that the first refrigerant and the second refrigerant both flow through a majority of a face area of condenser while remaining in two different circuits.

Abstract: A multiple tube bank heat exchanger includes a first tube bank including at least a first and a second flattened tube segments extending longitudinally in spaced parallel relationship and a second tube bank including at least a first and a second flattened tube segments extending longitudinally in spaced parallel relationship. The second tube bank is disposed behind the first tube bank with a leading edge of the second tube bank spaced from a trailing edge of the first tube bank. A continuous folded fin extends between the first and second flattened tube segments of both of said first tube bank and said second tube bank.

Abstract: A heat exchanger for receiving an airflow having an uneven intensity distribution across the heat exchanger and for flowing refrigerant within the heat exchanger. The heat exchanger includes sections of microchannel tubes for flowing refrigerant through at least one pass through the heat exchanger, wherein the sections are configured according to the airflow across the heat exchanger. The heat exchanger may be used in an HVAC system. A method may also be performed to manufacture the heat exchanger.

Abstract: An HVAC system having a fixed orifice expansion device coupled to an evaporator coil is provided. In one embodiment, an expansion device coupled to an evaporator coil includes a flow restrictor and an evaporator inlet manifold. The flow restrictor includes multiple fixed orifices aligned with the refrigerant distribution tubes to restrict flow of refrigerant from the evaporator inlet manifold into the refrigerant distribution tubes through the multiple fixed orifices. Additional systems, devices, and methods are also disclosed.

Abstract: An HVAC system for use with a first refrigerant and a second refrigerant. The HVAC system may include a first refrigerant circuit for use with the first refrigerant, a second refrigerant circuit for use with the second refrigerant, and a heat exchanger. The first refrigerant circuit and the second refrigerant circuit may each include may include a compressor, an expansion device, and an evaporator. The compressor may include a first upper section, a first lower section, a second upper section in fluid communication with the first lower section, and a second lower section in fluid communication with the first upper section. The first upper section, the first lower section, the second upper section, and the second lower section may be arranged such that the first refrigerant and the second refrigerant both flow through a majority of a face area of condenser while remaining in two different circuits.

Abstract: The present disclosure relates to a heating, ventilation, and air conditioning (“HVAC”) system include a supply damper, a return damper, and a defrost damper which are operable to control a supply airflow, a return airflow, and a defrost airflow to flow between a supply duct, a return duct, and an indoor heat exchanger without substantially flowing into and substantially cooling an indoor space. A reheat coil may also warm the supply air flow and a defrost return line may be used to bypass a bi-flow expansion device and an indoor heat exchanger.

Abstract: The present disclosure relates to a multi-circuit heating, ventilation, and air conditioning (“HVAC”) system for use with a first refrigerant in a first refrigerant circuit and a second refrigerant in a second refrigerant circuit. The second refrigerant circuit is fluidically isolated from the first refrigerant circuit. Additionally, a first sensor is operable to detect a leak of at least one of the first and second refrigerants or is operable to measure temperature or pressure from the first refrigerant circuit or the second refrigerant. The multi-circuit HVAC system further including a controller programmed to receive the measurement from the sensor to identify the circuit or circuits that are leaking, to turn off operation of the leaking circuit or circuits, and if only one circuit is leaking, operate only the other of the circuits.

Abstract: An HVAC with multiple blowers and a shared motor controller is provided. In one embodiment, an HVAC system includes a first blower installed within a cabinet. The first blower has a motor and a fan connected to be driven by the motor of the first blower. The HVAC system further includes a second blower installed within the cabinet. The second blower also includes a motor and a fan connected to be driven by the motor of the second blower. A motor controller is connected to control operation of both the motor of the first blower and the motor of the second blower. Additional systems, devices, and methods are also disclosed.

Abstract: A heat exchanger for receiving an airflow having an uneven intensity distribution across the heat exchanger and for flowing refrigerant within the heat exchanger. The heat exchanger includes sections of microchannel tubes for flowing refrigerant through at least one pass through the heat exchanger, wherein the sections are configured according to the airflow across the heat exchanger. The heat exchanger may be used in an HVAC system. A method may also be performed to manufacture the heat exchanger.

Abstract: A heating, ventilation, and air-conditioning (HVAC) system that includes an outdoor heat exchanger (HX) and outdoor fans. The outdoor fans are arranged in either an in-line configuration or a staggered configuration to satisfy one or more requirements to optimize the airflow across the outdoor HXs.