A system includes a dynamic compressor and a controller having a processor and a memory. The compressor includes a first compressor stage having a first variable inlet guide vane (VIGV) and a second compressor stage having a second VIGV. The memory stores instructions that program the processor to operate the compressor at a current speed, a first position of the first VIGV, and a second position of the second VIGV to compress the working fluid, and to determine if a condition is satisfied. If the condition is not satisfied, the processor is programmed to continue to operate the compressor at the current speed, the first position of the first VIGV, and the second position of the second VIGV. If the condition is satisfied, the processor is programmed to change the second position of the second VIGV to a third position and maintain the first position of the first VIGV.

A hybrid controller for a thermal control unit for controlling the temperature of a device under test (DUT) is described that uses information from an in independent heat-injecting control loop as a fast-responding proxy for relative changes in DUT test head load. This information provides additional feedback to the refrigeration sub-system's controller(s), resulting in achieving the overall system goal of temperature control of the DUT over a wide range of set point temperatures and the rapidly changing DUT head load.

An air quality adjustment system includes an adsorption-desorption portion that adsorbs a target substance in air and desorbs the target substance adsorbed by the adsorption-desorption portion. The adsorption-desorption portion accumulates an energy in adsorbing the target substance and releases, in desorbing the target substance, at least part of the energy accumulated.

An air conditioner unit includes a variable speed compressor for circulating refrigerant through refrigeration loop and a controller configured to initiate an operating cycle, start a compressor transition timer, and determine an unfiltered compressor speed. The unfiltered compressor speed is fixed based on the selected operating mode until the compressor transition timer reaches a predetermined transition delay time, after which the unfiltered compressor speed is determined using a closed loop feedback control algorithm. The controller is further configured to operating the variable speed compressor at a target compressor speed that is modified from the unfiltered compressor speed based on the identification of a speed modification condition, such as a dehumidification deficiency a speed restriction, or the identification of one or more resonance avoidance zones.

The present disclosure generally relates refrigeration systems for temperature-controlled displays. For instance, one exemplary embodiment relates to a refrigeration system that includes a refrigeration circuit, a cooling circuit, a reclaim heat circuit, and a floor heating system. The refrigeration circuit includes a compressor driven by a brushless DC motor operable at multiple different speeds, a first heat exchanger, an expansion device, and a cooling unit in fluid communication using a first working fluid. The cooling unit is arranged to cool a temperature-controlled storage device. The cooling circuit includes a pump and a second heat exchanger in thermal communication with the first heat exchanger using a second working fluid such that the first heat exchanger is liquid-cooled by the second working fluid. The reclaim heat circuit is in fluid communication with the cooling circuit. The floor heating system is coupled to the heat reclaim circuit as a reclaim heat load.

A chiller is provided that includes a deionization filter to remove ionic substances in cooling waters, and that is of such a small size as to save energy and costs. The chiller also includes cooling-water circuits, and a refrigeration circuit. The refrigeration circuit includes heat-exchange-path sections. The heat-exchange-path sections include respective heat exchangers. The cooling-water circuits and includes tanks, first supply lines, second supply lines, and return lines. The chiller includes a filtering line branching off from the second supply line of the cooling-water circuit and connected to the return line of the cooling-water circuit. The filtering line is provided with the deionization filter.

Embodiments of the present disclosure are directed toward purge units of vapor compression systems, and methods of control thereof, that improve efficiency by selectively activating and deactivating the purge unit in response to one or more conditions to, for example, enable refrigerant-to-air ratios within the purge unit within certain industry standards while still minimizing the durations of the purge cycles. For example, in certain embodiments, these conditions may include conditions within the chiller condenser, time since last purge activation, time since last venting of non-condensables, and combinations thereof. By reducing an amount of time that the purge unit would be active without removing a substantial amount non-condensables from the vapor compression system, present embodiments reduce the power consumption of the purge unit, as well as the vapor compression system as a whole, while still being responsive to prevent or mitigate a loss of efficiency due to a substantial accumulation of non-condensables in the condenser of the vapor compression system.

The present disclosure relates to a heating, ventilation, and/or air conditioning (HVAC) system having a heat exchanger configured to thermally regulate a supply air flow, where the heat exchanger includes a thermoelectric device, a first plurality of fins coupled to the thermoelectric device, and a second plurality of fins coupled to the thermoelectric device. The first plurality of fins extend into a supply air flow path of the supply air flow to transfer thermal energy between the thermoelectric device and the supply air flow and the second plurality of fins convectively transfer thermal energy between the thermoelectric device and a working fluid exterior the supply air flow path.

An air conditioner unit includes a variable speed compressor for circulating refrigerant through refrigeration loop and a controller configured to initiate an operating cycle, start a compressor transition timer, and determine an unfiltered compressor speed. The unfiltered compressor speed is fixed based on the selected operating mode until the compressor transition timer reaches a predetermined transition delay time, after which the unfiltered compressor speed is determined using a closed loop feedback control algorithm. The controller is further configured to operate the variable speed compressor at a target compressor speed that is modified from the unfiltered compressor speed based on the identification of a speed modification condition, such as a dehumidification deficiency, a speed restriction, or the identification of one or more resonance avoidance zones.

A control method for a refrigerator includes sensing a temperature of a storage room; operating a cool air supply at a cooling power when the sensed temperature of the storage room is equal to or above a first reference temperature; operating the cool air supply at a delay power, which is less than the cooling power, when the sensed temperature of the storage room is equal to or below a second reference temperature, which is less than the first reference temperature while the cool air supply is operating at the cooling power; and adjusting the cooling power or the delay power of the cool air supply according to the temperature of the storage room while the cool air supply is operating at the delay power, and operating the cool air supply at the determined adjusted cooling power or delay power.