A refrigeration system includes an evaporator, a condenser, a compressor, a capillary tube, and an expansion device. The compressor is configured to circulate a refrigerant between the evaporator and the condenser. The capillary tube is configured to receive the refrigerant from the condenser. The expansion device is configured to receive the refrigerant from the capillary tube and provide the refrigerant to the evaporator. The expansion device is adjustable to control a flow of the refrigerant through the capillary tube.

An air-conditioning apparatus according to the present disclosure includes a heat medium circulation circuit, a heat-source-side device, and a voltage drop device. In the heat medium circulation circuit, a pump, an indoor heat exchanger, and a flow control device are connected by pipes to circulate the heat medium. The pump sends a heat medium that contains water or brine and transfers heat. The indoor heat exchanger causes heat exchange to be performed between the heat medium and an indoor air in an air-conditioned space. The flow control device controls a flow rate of the heat medium in the indoor heat exchanger. The heat-source-side device heats or cools the heat medium before the heat medium is sent to the indoor heat exchanger. The voltage drop device reduces a voltage that is applied to the pump based on a value of a current that is supplied to the pump, in association with a flow rate of the heat medium in the heat medium circulation circuit.

An inverter for driving a motor that has a switchable connection of windings and drives a load element having a periodically varying load torque is provided. The inverter is controlled so that an output torque of the motor follows the periodic variation of the load torque. The inverter is controlled so that a current flowing through the motor is zero during a period including a minimum torque phase at which the load torque is at or near a minimum value. The connection is switched while the current flowing through the motor is zero. It is possible to switch the connection of the windings while the motor is rotating, and avoid an increase in apparatus size.

A monitoring system for apparatus and systems in commercial and residential properties is provided. The monitoring system consists of a head unit and a tail unit, each of which has one or more sensors that measure performance parameters that are important to understanding the performance of the apparatus and system being monitored. As an example, an HVAC system may be monitored to determine when an air filter needs to be changed, or to predict when failure of the HVAC system may be imminent. The sensor array in the head unit and tail unit measure performance and report alerts and historical system performance to users through a mobile app, social media accounts, or any other system for communicating over a wired or wireless network connection.

An all-inclusive fluid flow device that can variably magnify differential pressure, measure, and control a flow of a fluid is described. Various procedures, including measuring, controlling, balancing, or calibration procedures can leverage a variably magnified differential pressure measurement. Differential pressure measurements can be measured across the fluid flow device such that a first pressure measurement is taken upstream of the fluid flow device while a second pressure measurement is taken downstream of the fluid flow device. Moreover, one or more of the various pressure measurements, and in particular the downstream pressure measurement, can be performed at stagnation zone where the flow has stagnated. Such can provide significant magnification and/or turndown capabilities and the magnification can vary based on a damper position and/or apertures dimensions.

A control system that uses an algorithm to control the fan speed in a cooling system for an engine is disclosed. The algorithm is adapted to maintain a cooling medium at a set temperature instead of an operating temperature range of the cooling medium. The algorithm is also adapted to maintain a cooling medium at a set temperature and to build a cooling safety margin in response to an engine output torque percentage that is below an output torque percentage setpoint.

A dynamic air supply system for controlling ventilation in a clean room, wherein the clean room comprises a clean area subject to contamination, comprising a radiant panel arranged within a ceiling above the clean area, a first air supply diffuser and a second air supply diffuser arranged within the ceiling, a controller coupled with the air supply diffusers for controlling the air supply. The first air supply diffuser and the second air supply diffuser are arranged on opposite sides of the radiant panel. The first air supply diffuser and the second air supply diffuser are arranged to diffuse air flows along the radiant panel and towards clean area. The controller is configured to change the air supply diffusers between nursing mode and normal mode, wherein the supply air volume in normal mode is 10%-65% of the supply air volume in nursing mode.

A compressor system including a compressor, a cooling device and a control apparatus, wherein the control apparatus is configured to control the cooling device independently of the operation of the compressor and to be capable of dynamically modifying a control parameter (T.sub.air, T.sub.oil) of an actuator and/or the actuator for the actuation of the cooling device.

A method and computing device for inferring an airflow of a controlled appliance operating in an area of a building. The computing device stores a predictive model. The computing device determines a measured airflow of the controlled appliance and a plurality of consecutive temperature measurements in the area. The computing device executes a neural network inference engine using the predictive model for inferring an inferred airflow based on inputs. The inputs comprise the measured airflow and the plurality of consecutive temperature measurements. The inputs may further include at least one of a plurality of consecutive humidity level measurements in the area and a plurality of consecutive carbon dioxide (CO2) level measurements in the area. For instance, the controlled appliance is a Variable Air Volume (VAV) appliance and a K factor of the VAV appliance is calculated based on the inferred airflow.

A system for modulating hot gas reheat operation of a heating, ventilation, and/or air conditioning (HVAC) system with multiple compressors, wherein the HVAC system is configured to regulate air provided to multiple zones. The system includes a controller configured to respond to a call for dehumidification in the absence of a call for cooling by sequentially energizing a first compressor of the multiple compressors in a reheat mode of the first compressor, energizing a second compressor of the multiple compressors in a cooling mode of the second compressor, energizing a third compressor of the multiple compressors in a reheat mode of the third compressor initially at full capacity, and energizing a fourth compressor of the multiple compressors in a cooling mode of the fourth compressor.