A rotation locking system of a motor of a fan is provided. A closed-loop control circuit outputs an initial duty cycle signal according to a current rotational speed and a target rotational speed. A driver circuit outputs a driving signal to the motor to drive the motor to rotate according to the initial duty cycle signal. A lookup table arithmetic circuit looks up, from a lookup table, two reference duty cycles correspond to two reference rotational speeds that are respectively equal to the current rotational speed and the target rotational speed. The lookup table arithmetic circuit calculates a difference between the two reference duty cycles. A speed feedback control circuit compensates the initial duty cycle signal according to the difference to output a final duty cycle signal to the driver circuit. The driver circuit drives the motor to rotate according to the final duty cycle signal.

In the solution put forth, there is a frame structure (122) and an inner surface structure (124) in an installation frame (110) of an exhaust blower (108) of a building (100). A bottom part (130) of the frame structure is intended to be installed towards a lead-through (106) of the building, and a top part (132) towards the exhaust blower installed over it. The frame structure surrounds the inner surface structure so that it does not cover bottom and top parts (126, 128) of the inner surface structure. The inner surface structure forms a suction channel (134) allowing exhaust air (114) flow through the frame. Inside the installation frame, a controller (112) has been installed, adapted to measure the exhaust air flowing in the suction channel and to generate, on the basis of the measurement, a control command for the exhaust blower to control the operation of the exhaust blower.

Heat rejection devices, including cooling towers, condensers and closed circuit coolers, having side-mounted backward-curved centrifugal fans mounted on top of the device, above a fan plenum instead of a top-mounted axial fan. Heat rejection capability can be easily modified by adding or subtracting fans without impacting unit footprint. Also, the ability to handle higher static pressures allows for the use of a more densely packed heat exchanger in the same footprint unit, which will increase the unit performance.

An air treatment device includes a casing with an air inlet and an air outlet. Air flows through the casing and an air treatment section in the casing. The air treatment section includes a fan for generating a flow of air from the air inlet to the air outlet, a filtering means arranged within the flow of air, a first pressure sensor to measure a first pressure in the flow of air, a second pressure sensor to measure a second pressure in a room or cabin surrounding the air treatment device, and a control unit. The control unit is configured to adapt a speed of the fan based on the measured first pressure and the measured second pressure to control a flow of air through the air treatment device.

A refrigerator can include a storage compartment having a storage space and an opening; at least one door coupled to the storage compartment to open and close a part of the storage compartment; a compressor configured to provide the storage compartment with freezing capacity or cooling capacity; a processor configured to control driving of the compressor; and a memory operably connected to the processor and configured to store code to cause the processor to in response to recognizing placement of an item in the storage space, determine whether the item is an overload item to generate a determination result; and control the driving of the compressor to adjust a temperature of the storage space based on the determination result.

A freezer case includes a refrigeration system and a controller. The controller is configured to store a plurality of setpoint instruction sets associated with a plurality of possible operating modes, select a current operating mode from the plurality of possible operating modes, assign a value for the superheat setpoint by executing the setpoint instruction set associated with the current operating mode, control the refrigeration system in accordance with the superheat setpoint.

Methods and systems described perform air cleaning and/or sanitization in a heating, ventilation, air conditioning, and/or refrigeration (HVACR) system by detecting a concentration of airborne contaminants in a space serviced by the HVACR system. The detected concentration of airborne contaminants is determined whether it exceeds a threshold relative to a capacity of a first air cleaner. When the detected concentration of airborne contaminants exceeds the threshold, a second air cleaner is selected and enabled to be activated in the space. When the detected concentration of airborne contaminants does not exceed the threshold, the first air cleaner is selected and enabled to be activated in the space. The first air cleaner has a cleaning material different from the second air cleaner, and the first air cleaner, relative to the second air cleaner, treats the space at a lower concentration of airborne contaminants. The second air cleaner includes specifically designed cleaner modules.

A control system is provided to optimize a compressor that has a variable guide vane position and a variable speed set point. One or more controllers receive a process set point for a main process variable for a first performance control application and a deviation set point for a surge deviation level for a second performance control application. The first performance control application operates a first independent primary control loop to control the main process variable at the process set point by manipulating the variable guide vane position. The second performance control application operates a second independent primary control loop to control a surge deviation level at the deviation set point by manipulating the variable speed set point. The second performance control application also executes a limit control loop to limit the main process variable at a limit set point by manipulating the variable speed set point.

A plurality of air-releasing openings with inclined sidewalls are arranged at the periphery of the water tank of an aroma diffuser product, each air-release opening disposed in a position that is set at a certain angle along the inclined direction of the sidewalls. The certain angle being formed by the center longitudinal axis of the exit side of the opening relative to the radius of the water tank. A plurality of mist-releasing openings is arranged non-horizontally at the upper part of the water tank or the periphery of the water tank cover. An aroma diffuser or ultrasonic atomizer configured with the plurality of air-releasing openings and/or the plurality of mist-releasing openings.

Devices, systems, and methods are disclosed for cooling using both air and/or liquid cooling sub circuits. A vapor compression cooling system having both an air and liquid cooling sub circuit designed to service high sensible process heat loads that cannot be solely cooled by either liquid or air is provided.