A heating, ventilation, and air conditioning (HVAC) system for regulating humidity of an enclosed space. The HVAC system includes an evaporator coil. A metering device is fluidly coupled to the evaporator coil. A variable-speed compressor is fluidly coupled to the condenser coil and the evaporator coil and a controller is operatively coupled to the variable-speed compressor. A humidity sensor is operatively coupled to the controller and exposed to the enclosed space. Responsive to a determination that the relative humidity of the enclosed space exceeds the maximum humidity threshold, the controller adjusts a speed of the variable-speed compressor to increase latent capacity of the HVAC system. Responsive to a determination that the relative humidity of the enclosed space falls below the minimum humidity threshold, the controller adjusts a speed of the variable-speed compressor to decrease latent capacity of the HVAC system.

A method including: determining whether a cooling system is operating in a cooling mode, such that the cooling system is not operating in a reheat mode, a humidification mode or a dehumidification mode; determining whether the cooling system is operating in a compressor mode, such that the cooling system is not operating in a pump refrigerant economization mode; determining whether the cooling system is at steady-state; and if the cooling system is operating in the cooling mode and the compressor mode and is at steady-state, evaluating one or more rules to determine if a degradation symptom exists for the cooling system. The method further includes: subsequent to the evaluation, generating a degradation evaluation value to indicate whether the one or more rules are satisfied; and based on the degradation evaluation value, generating an alarm signal or performing a countermeasure.

An air conditioner includes an outdoor unit, a plurality of indoor units, a plurality of expansion valves which are provided upstream of indoor heat exchangers, a plurality of on-off valves which are provided upstream of the expansion valves, and control unit wherein when the indoor units include a stopping indoor unit and an operating indoor unit currently operating, and when a stopping of the stopping unit is due to thermostat-off operation, the control unit performs a procedure to stop the stopping unit, the procedure including closing an on-off valve that corresponds to the stopping unit and driving an indoor fan in the stopping unit until pressure in a part between the on-off valve and an expansion valve that corresponds to the stopping unit and pressure in a part downstream of the first expansion valve are equalized, fully opening the expansion valve, and stopping the indoor fan.

A refrigeration system includes a free cooling system having an air-cooled heat exchanger, where the air-cooled heat exchanger includes a fan configured to move air over coils of the air-cooled heat exchanger to remove heat from a coolant flowing through the air-cooled heat exchanger, and a mechanical cooling system with a refrigerant loop that includes an evaporator, a compressor, and a condenser disposed along the refrigerant loop, where the compressor is configured to circulate a refrigerant through the refrigerant loop, and wherein the evaporator is configured to receive the coolant and transfer heat from the coolant to the refrigerant. The refrigeration system also includes a controller configured to adjust a fan speed of the fan up to a threshold fan speed, to initiate operation of the compressor when the fan speed reaches the threshold fan speed, wherein the fan speed and a compressor speed of the compressor are based at least on an ambient air temperature and a cooling load demand.

A system includes a heat exchanger; a variable actuator in operative communication with the heat exchanger and configured to vary a flow of a first fluid through the heat exchanger in a continuous manner; a discrete actuator in communication with the heat exchanger and configured to vary a flow of a second fluid through the heat exchanger at one of at least two discrete rates; and a controller in communication with the variable actuator and the discrete actuator, wherein the controller is configured to adjust the position of the variable actuator within a range dependent upon a current position of the discrete actuator.

An air conditioner includes an outdoor unit and a plurality of indoor units connected to the outdoor unit. The outdoor unit sometimes sets an evaporation temperature or a condensation temperature that is different from a value that any of the indoor units has requested from the outdoor unit. The indoor units have indoor-side controllers that perform capacity control that adjusts capacity based on a degree of superheating or a degree of supercooling, an air volume, or an evaporation temperature or a condensation temperature while calculating a requested capacity that is determined from a current room temperature and a set room temperature. The indoor-side controllers, when performing the capacity control, determine at least one of the air volume and a target value of the degree of superheating or the degree of supercooling based on the evaporation temperature or the condensation temperature that is set by the outdoor unit.

A motor control interface system, comprising an interface communication module configured to connect to a wired control port of a rotating electronically controlled motor, such as in an HVAC system, wherein the interface communication module converts a rotating motor speed signal to a wireless signal for receipt by an external monitoring device. The speed output signal comprises a digital square wave signal, and the communication module implements a reciprocal frequency counter method to determine the speed of the motor. The interface communication module wirelessly transmits the motor speed information to a handheld wireless device, such as a smartphone.

An air conditioner which continues driving with a deteriorated gas leakage sensor is provided. An air conditioner of the present invention includes an outdoor unit including a compressor and an indoor unit connected with the outdoor unit and uses flammable refrigerant. The air conditioner includes: a refrigerant gas sensor; and a controlling unit configured to stop the compressor at occurrence of abnormality, when the refrigerant gas sensor detects refrigerant gas while the compressor is being driven. After the compressor is stopped as the refrigerant gas sensor detects the refrigerant gas, the controlling unit does not start driving of the compressor until an operation to cancel the abnormality is performed.

Air conditioner units and methods for operating air conditioner units are provided. A method includes determining an operational state of each heater bank of a plurality of heater banks of the air conditioner unit, and determining a speed of a blower fan of the air conditioner unit when the operational state of every heater bank is active. The method further includes comparing a blower fan motor rotational frequency to a rotational frequency threshold value when the speed is a low speed, and deactivating one of the plurality of heater banks when the blower fan motor rotational frequency is greater than the rotational frequency threshold value.

An air conditioning apparatus includes, a first heat exchanger, a second heat exchanger configured to exchange heat between a first heat medium and a second heat medium, flow rate control valves, and a pump. In a heating mode, a controller is configured to open the flow rate control valve corresponding to a heat exchanger, of the third heat exchangers, to which a request for air conditioning has been made, and to close the flow rate control valve(s) corresponding to a heat exchanger(s), of the third heat exchangers, to which the request for air conditioning has not been made. In a defrosting mode, when a temperature of the second heat medium is lower than a first determination temperature, the controller is configured to open at least one of the flow rate control valve(s) corresponding to the heat exchanger(s) to which the request for air conditioning has not been made.