A heating, ventilation, and/or air conditioning (HVAC) system includes a first condenser coil of a refrigerant circuit, wherein the first condenser coil is configured to receive a first refrigerant flow from a compressor of the refrigerant circuit, a modulating valve of the refrigerant circuit, and a control circuitry communicatively coupled to the modulating valve. The modulating valve is configured to receive a second refrigerant flow from the compressor and configured to direct the second refrigerant flow to a second condenser coil of the refrigerant circuit and to a reheat coil of the refrigerant circuit in a parallel flow arrangement, and the control circuitry is configured to operate the modulating valve to apportion the second refrigerant flow between the second condenser coil and the reheat coil based on a detected operating parameter of an air flow directed across the reheat coil.

An HVAC system includes an evaporator coil and a metering device. The HVAC system includes a variable-speed circulation fan and a condenser coil fluidly coupled to the metering device. A variable-speed compressor is fluidly coupled to the condenser coil and the evaporator coil. A controller is operatively coupled to the variable-speed compressor and the variable-speed circulation fan. A second temperature sensor is disposed in an enclosed space. The second temperature sensor measures temperature of the enclosed space and transmits the temperature of the enclosed space to the controller. The controller determines if the temperature of the enclosed space is below a minimum threshold. Responsive to a determination that the temperature of the enclosed space is below the minimum threshold, the controller modulates at least one of a speed of the variable-speed compressor and the variable-speed circulation fan to lower a discharge air temperature.

A domestic refrigerator has a refrigeration compartment and a container which can be accommodated in the refrigeration compartment and has a lower part for receiving products to be refrigerated and a cover that can cover the lower part. The container has an air inlet opening and an air outlet opening that is at a distance from the air inlet opening. The domestic refrigerator also has a controllable air flow adjustment device and is configured to vary a volume flow rate of an air flow, which enters the container from the refrigeration compartment through the air inlet opening, between at least two values by adjusting an adjustment parameter of the air flow adjustment device. Furthermore, a method ventilates the container which is accommodated in the refrigeration compartment and has the air inlet opening and the air outlet opening.

A system for charging an outdoor unit with refrigerant includes a sensor configured to measure a refrigerant concentration and a user device configured to receive the measured refrigerant concentration. The system includes that the user device is configured to, in response to the measured refrigerant concentration exceeding a threshold, generate and display an alert on a user interface of the user device indicating the measured refrigerant concentration exceeds the threshold.

In one aspect, a fan array fault response control system is provided for a cooling tower. The fan array fault response control system includes a fan interface configured to be in communication with a plurality of fans of the cooling tower and a processor operably coupled to the fan interface. The processor is configured to detect at least one non-operational fan of the plurality of fans. The processor configured to effect, in response to detecting the at least one non-operational fan, a reduced fan speed of at least one operational fan of the plurality of fans.

A decentralized condenser evaporator system includes a condenser system, a controlled pressure receiver, a subcooler system, and an evaporator system. The condenser system is positioned to receive a compressed gaseous refrigerant from a centralized compressor system. The condenser system is configured to condense the compressed gaseous refrigerant into a liquid refrigerant. The controlled pressure receiver is positioned to receive and store the liquid refrigerant. The subcooler system is positioned to receive the liquid refrigerant from the controlled pressure receiver. The subcooler system is configured to sub-cool the liquid refrigerant into a sub-cooled liquid refrigerant. The evaporator system is positioned to receive the sub-cooled liquid refrigerant from the subcooler system. The evaporator system is configured to facilitate providing a cooling operation to a cooling zone through evaporation of the sub-cooled liquid refrigerant flowing through the evaporator system into an evaporated gaseous refrigerant which is returned to the centralized compressor system.

A control method of a transcritical carbon dioxide composite heat pump system is disclosed, wherein the transcritical carbon dioxide composite heat pump system includes: a CO.sub.2 main circuit compressor, an air-cooling-air-cooling recombiner, a supercooling-evaporation recombiner, an evaporator and a CO.sub.2 auxiliary compressor; wherein the air-cooling-air-cooling recombiner comprises a CO.sub.2 main circuit, a CO.sub.2 auxiliary circuit and a water circuit; the supercooling-evaporation recombiner comprises a CO.sub.2 main circuit supercooling section and a CO.sub.2 auxiliary circuit evaporation section. The present invention includes two working modes according to the return water temperature, so that the unit has a wider application range and meets daily needs. There is only one heat exchanger for refrigerant and water. Compared with the three water and refrigerant heat exchangers in the conventional transcritical CO.sub.2 composite heat pump, the circulating water circuit is a single circuit with one inlet and one outlet.

A refrigeration system includes a supplemental heat exchanger operably disposed between a condenser and an evaporator. This supplemental heat exchanger is located in selective fluid communication with the air in the conditioned space, and can be toggled between an “invisible” mode in which the heat exchanger acts as a simple fluid conduit between the condenser and evaporator, and a “humidity reduction” mode in which the heat exchanger operates to transfer heat from hot refrigerant to the colder conditioned space. This addition of heat into the conditioned space decreases the relative humidity of the conditioned space and subcools the refrigerant leading to the expansion valve and evaporator. This subcooling of the liquid enables the evaporator to operate at a lower temperature which enhances the moisture removal from the air moving through the evaporator. The supplemental heat exchanger may be located in a physically elevated position relative to the remainder of the conditioned space to utilize stratification of hot air to create a default “invisible mode” without inducing airflow.

A motor drive control device includes a three-phase rectifier; a boosting circuit including a reactor, a switching element, and a backflow preventing element and boosts a direct-current bus voltage supplied from the three-phase rectifier; a smoothing capacitor; an inverter circuit; a boosting control unit; an inverter control unit; and a circuit protecting unit suppresses a ripple current flowing through the smoothing capacitor. In the circuit protecting unit, a correlation of an on-duty ratio of the switching element included in the boosting circuit, the output power of the inverter circuit, and an estimated ripple current are set. On the basis of the on-duty ratio of the switching element, output power of the inverter circuit, and the correlation, the circuit protecting unit determines an estimated ripple current flowing through the smoothing capacitor. When the estimated ripple current exceeds a preset threshold, the circuit protecting unit suppresses the ripple current.

A system for charging an outdoor unit with refrigerant includes a sensor configured to measure a refrigerant concentration and a user device configured to receive the measured refrigerant concentration. The system includes that the user device is configured to, in response to the measured refrigerant concentration exceeding a threshold, generate and display an alert on a user interface of the user device indicating the measured refrigerant concentration exceeds the threshold.