Abstract: A method is described for operating a refrigerant circuit that includes a compressor with a driveshaft and one or more gas bearings for supporting the driveshaft. The method includes operating the refrigerant circuit in a first mode which includes supplying gaseous working fluid compressed by the compressor to the one or more gas bearings of the compressor, and the one or more gas bearings using the compressed gaseous working fluid to support the driveshaft. The method includes operating the refrigerant circuit in a second mode which includes supplying liquid working fluid to the one or more gas bearings of the compressor, and the one or more gas bearings using the liquid working fluid to support the driveshaft. A refrigerant circuit includes a compressor, a condenser, an expander, an evaporator, and a controller configured to selectively operate the refrigerant circuit in a least a first mode and a second mode.

Abstract: Architectures or techniques are presented that can improve operation of permanent magnet (PM) motors, which can be part of a compressor or other heating, ventilation, and air conditioning (HVAC) device. Such improvements can be achieved by integration of inductive filtering into the motor assembly. A higher overall inductance can reduce current ripple and can further result in a lower total harmonic distortion, reduced power loss, and reduced heat generated. For example a first architecture can include a ferromagnetic core element in the PM motor that can cause a non-torque-producing reluctance path to the shaft. A second architecture can integrate a signal filter, which is customarily external, into a housing of the PM motor. Such can significant reduce costs and provide other advantages. A third architecture can couple an inductor (e.g., of the signal filter) to the shaft. Rotation of the shaft can thus serve to provide additional cooling for the inductor.

Abstract: Methods and related systems for charging a refrigerant into a climate control system. In an embodiment, the method includes (a) coupling a storage tank to a refrigerant loop of the climate control system through a charging valve; (b) opening and closing the charging valve in a plurality of cycles; and (c) flowing refrigerant from the storage tank to the refrigerant loop through the charging valve when the charging valve is open, during (b). In addition, the method includes (d) determining a detected saturated temperature of the refrigerant within the refrigerant loop after each cycle of the plurality of cycles; and (e) adjusting an amount of time that the charging valve is open during each cycle of the plurality of cycles during (b) as a function of the detected saturated temperature from a previous cycle of the plurality of cycles.

Abstract: Methods and related systems for controlling an indoor air temperature for a heat pump system are disclosed. The method includes (a) determining an outdoor coil temperature of an outdoor heat exchanger and a speed of a compressor of a heat pump system, (b) determining a target indoor coil temperature of the indoor coil based on the outdoor coil temperature and the speed of the compressor, and (c) adjusting a speed of air flowing across the indoor coil based on a difference between a current indoor coil temperature and the target indoor coil temperature to reduce the difference between the current indoor coil temperature and the target indoor coil temperature.

Abstract: Methods and related systems for controlling indoor relative humidity include (a) determining a target dew point temperature based on desired indoor conditions for the indoor space, and (b) determining an initial dew point temperature based on an initial set of current indoor conditions of the indoor space. The method includes (c) determining a target coil temperature of a coil of an indoor heat exchanger of the climate control system based on the target dew point temperature and the initial dew point temperature, and (d) adjusting a speed of air flowing across the coil or a speed of a compressor of the climate control system after (c) based on the target coil temperature to reduce a difference between a coil temperature of the coil and the target coil temperature.

Abstract: Methods and related systems for operating a furnace are disclosed. In an embodiment, the method includes activating a burner assembly and a first fan of the furnace to combust fuel and air and circulate combustion gases along a flow path extending through a heat exchanger of the furnace. In addition, the method includes operating a second fan of the furnace to circulate air across an external surface of the heat exchanger of the furnace and produce a conditioned airflow. Further, the method includes monitoring one or more parameters of a motor of the second fan indicative of an airflow rate of the conditioned airflow, and deactivating the burner assembly, whereby combustion of the fuel and air in the furnace ceases, in response to the one or more parameters indicating that the airflow rate is less than a minimum airflow rate.

Abstract: A transport refrigeration system (TRS) for an enclosed space of a transport unit that includes a ventilation pathway to direct air to flow from the enclosed space. The TRS includes a refrigerant circuit with an evaporator configured to cool the air, and a CO2 scrubber. The CO2 scrubber includes a metal organic framework (MOF) configured to adsorb CO2 from the air in an adsorption mode and is regenerated with ambient air in a regeneration mode. A transport unit includes an enclosed space for storing produce, a ventilation pathway, and a TRS. A method of conditioning an enclosed space of a transport unit includes operating a TRS in a first mode that cools air from the enclosed space and adsorbs, with a MOF in a CO2 scrubber, CO2 from the air, and operating the TRS in a second mode that regenerates the MOF with ambient air.

Abstract: A method for purifying air within a space is provided. The method includes a controller determining whether an ON signal is received. Upon determining that the ON signal is received, the controller instructs an air sanitizer of an air sanitization system to turn ON to purify an airflow passing through the air sanitization system, and instructs an air movement fan/blower to operate in order to direct the airflow into the space. Upon determining that the ON signal is not received, the controller instructs the air movement fan/blower and the air sanitizer to be OFF.

Abstract: A compressor including a housing, a shaft configured to be rotated relative to the housing to compress a refrigerant, a motor configured to drive the shaft, a lubrication system configured to supply lubricant to the compressor, and a bearing configured to support the shaft. The shaft includes a wear-resistant sleeve-like treatment on at least a portion of an outer surface of the shaft adjacent the bearing. The lubricant is POE oil or a lubricant blend composition that includes two or more lubricants, the two or more lubricants including a first lubricant and a second lubricant.

Abstract: Multi-compressor chiller systems can be efficiently operated by determining real time efficiency curves for the compressors currently in operation, along with any compressors that may be added to address demand, and using these efficiency curves to determine changes to compressor operation to improve efficiency in meeting chiller demand. The efficiency curves can be parabolic curves. The data used to determine the efficiency curves can be obtained through operation at a variety of lift points and a variety of load points within those lift points. The efficiency curves can be solved to find intersections where there may be staging points for adding or subtracting compressors from operation to efficiently meet demand. This operation can be automated through a controller of a control system for the multi-compressor chiller system.

Abstract: Example embodiments of the present disclosure relate to improved HVAC devices and kits for HVAC devices that improve the sound attenuation associated with the device, particularly low-frequency noise. An example embodiment includes an improved furnace including a housing with a combustion air chamber, a heat exchanger chamber, and a circulation blower chamber, wherein the combustion air chamber comprises a burner assembly and a combustion air fan, the furnace also includes a sound attenuation layer including a first acoustic metamaterial layer coupled to the combustion air chamber and tuned to attenuate sound for a first frequency band, one or more housing openings fluidly connecting the combustion air chamber to an environment outside the housing, wherein the sound attenuation layer includes a discontinuous section that aligns with one or more of the housing openings.

Abstract: An air handler includes a housing with a heat exchanger core. The housing includes a faceplate, a roof panel, a base panel, a first side panel, and a second side panel. A first tunnel and a second tunnel are connected to the housing at the faceplate. A septum protrudes from the faceplate and connects the core at a front edge. The air handler further includes a first recirculation path and a second recirculation path inside the housing. The first and second recirculation paths are defined by the septum, the housing, and the core. The first and second recirculation paths are configured to direct a portion of airflow from the first tunnel to the second tunnel. The air handler further includes a first damper and a second damper disposed on the faceplate and configured to obstruct the first recirculation path and the second recirculation path respectively.

Abstract: A compressor for a heat transfer circuit includes a variable frequency drive (VFD), an electric motor that rotates a driveshaft, bearing(s) for supporting the driveshaft, a backup gas supply, and a power supply. During a utility power interruption, the backup gas supply operates utilizing DC electrical power generated by a back electromotive force of the electric motor. A method of operating an electric power supply system for a compressor includes operating in a utility power mode and operating in a backup power mode during a utility power interruption. In the utility power mode, AC electrical power is supplied from the VFD to the motor. In the backup power mode, DC electrical power generated in the VFD by a back electromotive force of the motor it used to operate a backup gas supply to supply compressed working fluid to gas bearing(s) of the compressor.

Abstract: HVAC components having improved efficiency are described. In one embodiment, excessive sleep current draw in a battery-powered device having a microcontroller is detected by measuring a voltage drop across a MOSFET device coupled in a forward-conducting orientation in series between the battery and the microcontroller, causing a transistor to conduct when the voltage drop exceeds a predetermined threshold to generate a first trigger signal, integrating the first trigger signal to generate a second trigger signal, and generating an interrupt to the microcontroller. In another embodiment, a battery-saving method of operating an HVAC component includes maintaining the HVAC device in the sleep mode, receiving a user input to wake the device, transmitting a data request and returning the HVAC component to the sleep mode, waking up the HVAC device to poll an adjacent network node storing a cached response, displaying the response, and returning the HVAC device to sleep.

Abstract: Devices, systems, and methods are disclosed for reducing leakage current in power converters, such as for HVAC systems, to facilitate compatibility with GFCI devices. In various embodiments, the power converter may include components to filter and/or reduce common mode noise, such as by removing high frequency components of the common mode noise, while maintaining leakage current below a trip threshold of a GFCI device.

Abstract: Architectures or techniques are presented that can learn relationships between graphical elements presented by a user interface and physical conditions that exist in an environment. Furthermore, the architectures or techniques can, potentially based on the learned information, present the graphical elements to the user interface in a manner that is determined to be more efficient. For example, graphical elements that were historically accessed when a particular physical condition is true can be identified. These identified graphical elements can then be presented in a location of the user interface that is determined to be favorable to rapid or efficient selection at times with the particular physical condition is determined to be satisfied.

Abstract: A lubricant supply system is for a compressor that compresses a first working fluid in a heat transfer circuit. The lubricant supply system includes a lubricant tank, a lubricant pathway for supplying lubricant from the lubricant tank to one or more bearings of the compressor, and a lubricant refrigeration system with a lubricant heater and a lubricant cooler. The lubricant heater configured to heat the lubricant discharged from the one or more bearings and the lubricant cooler configured to cool the lubricant flowing through the lubricant pathway. A method of lubricating a compressor includes heating the lubricant, directing the lubricant from a lubricant tank through a lubricant pathway to one or more bearings of the compressor, and cooling the lubricant passing through the lubricant pathway.