A method for operating a heat pump (20; 300) includes operating in a cooling mode wherein heat is absorbed by refrigerant in the indoor heat exchanger (26) and rejected by refrigerant in the outdoor heat exchanger (24). The heat pump switches to operation in a heating mode wherein heat is rejected by refrigerant in the indoor heat exchanger, heat is absorbed by refrigerant in the outdoor heat exchanger, and there is an ejector (60) motive flow and ejector secondary flow. In the heating mode a refrigerant pressure (PH) or temperature (TL) is measured and, responsive to the measured refrigerant pressure or temperature, at least one of a fan speed is changed and a needle (132) of the ejector is actuated.

A method for air-conditioning of watercraft and the like using a device with: an electronically controlled variable-r.p.m. compressor, a main gas/water condenser (5), at least one environmental heat-exchanger (3) with an electronically controlled fan (14), at least one electronically controlled expansion valve (8), and at least one first electronic control unit (4) programmed for calculating continuously a temperature deviation detected (DeltaT=T_ad−T_a), and as a function of said temperature deviation regulating in combination, the r.p.m. of the compressor (1), opening of the flow valve (8), and the r.p.m. of the fan of the heat-exchanger (3).

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.

There is provided a vehicle air conditioning apparatus capable of removing frost formed on an outdoor heat exchanger at the same time as cooling of a battery. The vehicle air conditioning apparatus performs the operation in a first battery cooling mode, a second battery cooling mode, or a solo battery cooling mode, when it is determined that the battery needs to be cooled and also determined that the frost formed on the outdoor heat exchanger needs to be removed. By this means, it is possible to cool the battery and melt the frost formed on the outdoor heat exchanger at the same time by the battery cooling operation, and therefore it is possible to reduce the power consumption compared to the case where the battery cooling operation and the defrosting operation are performed individually.

A system includes an electronic power converter and a controller. The electronic power converter supplies power to one or more motor drives of an HVAC and/or refrigeration system. The controller obtains a plurality of pulse width modulation (PWM) algorithms. Each PWM algorithm has an associated harmonic signature. The controller further determines one or more resonance frequencies associated with the HVAC and/or refrigeration system. The controller also selects a first PWM algorithm from the plurality of PWM algorithms based at least in part on the harmonic signature associated with the first PWM algorithm mitigating the one or more resonance frequencies associated with the refrigeration system. The controller further operates the electronic power converter according to the first PWM algorithm.

An outdoor unit includes at least one heat exchanger, a first motor including a first fan, a second motor including a second fan, an inverter that applies voltage to the first motor and the second for respectively, a connection switching unit that switches the voltage applied to the second motor between on and off, and a control unit that controls the inverter and the connection switching unit. The inverter is disposed closer to the first motor than to the second motor.

In order to restrain damage of a component due to rush current, a main relay in a power source circuit is not turned on and does not conduct a power source line even when a heat source microcomputer is activated with a capacitor not sufficiently charged. This configuration avoids start of charging the capacitor without current limitation, to restrain damage of the component due to rush current.

A heat exchanger system that includes a heat exchanger that includes a plurality of circuits wherein the heat exchanger is configured to exchange heat between a refrigerant and a working fluid. The heat exchanger system also includes a valve configured to fluidly couple a circuit of the plurality of circuits to a flow path of the refrigerant. Further, the heat exchanger system includes a controller that is configured to receive feedback indicative of an operating parameter of the heat exchanger system and actuate the valve based on the operating parameter.

A power converting apparatus includes: a rectifying unit configured to rectify an input AC power, a buck converter that is configured to step down a voltage of the rectified power and that is configured to output DC power having the step down voltage, a first inverter that is connected to an output terminal of the buck converter and that is configured to convert the DC power into AC power to drive a first motor, a second inverter that is connected to the output terminal of the buck converter, that is disposed in parallel to the first inverter, and that is configured to convert the DC power into AC power to drive a second motor, and a converter controller configured to control an output voltage of the DC power of the buck converter.

A method for operating a heat pump (20; 300) includes operating in a cooling mode wherein heat is absorbed by refrigerant in the indoor heat exchanger (26) and rejected by refrigerant in the outdoor heat exchanger (24). The heat pump switches to operation in a heating mode wherein heat is rejected by refrigerant in the indoor heat exchanger, heat is absorbed by refrigerant in the outdoor heat exchanger, and there is an ejector (60) motive flow and ejector secondary flow. In the heating mode a refrigerant pressure (P.sub.H) or temperature (T.sub.L) is measured and, responsive to the measured refrigerant pressure or temperature, at least one of a fan speed is changed and a needle (132) of the ejector is actuated.