Abstract: In multiple system type air conditioner, there are provided an auxiliary outdoor heat exchanger provided in an outdoor unit, and defrosting device that, on heating operation, periodically or as needed feeds the refrigerant discharged from the compressor to the outdoor heat exchanger and all the indoor heat exchangers. After the refrigerant has passed through the outdoor heat exchanger and all the indoor heat exchangers, the refrigerant returns to the compressors through the auxiliary outdoor heat exchanger.

Abstract: A central air conditioning system includes a compensating control function in which the prescribed target temperature Tfs of the conditioned air supplied from the air conditioning apparatus to a main duct is changed from the original value to a prescribed value of a modified target temperature Tfm to establish the target temperature Tfs when the actual room temperature Ta in each room does not achieve a corresponding desired room temperature Ts even though the damper of the corresponding air volume control unit is positioned at either the fully opened position or the closed position. The temperature of the conditioned air from the air conditioning apparatus is controlled in accordance with the target temperature Tfs, and the target temperature Tfs of the conditioned air is further changed to successive values of the modified target temperature Tfm until the actual room temperature Ta in each room achieves the corresponding desired room temperature Ts.

Abstract: A rapid increase in the static pressure in the air duct which occurs while the damper is moving to the fully closed position is avoided by maintaining the damper at a preclosed position between fully opened and fully closed positions for a prescribed period and by simultaneously reducing the amount of conditioned air supplied to the air duct while the damper is positioned at the pre-closed position to regulate the static pressure in the air duct to a desirable level. Thus, air leakage noise which occurs in the air duct when the static pressure in the air duct rapidly increases for a short time can be avoided.

Abstract: A single outdoor unit has at least an inverter circuit, a compressor motor, a variable capacity compressor, and an outdoor heat exchanger. A plurality of indoor units each have at least an indoor heat exchanger and an air-conditioning load detector. A distribution unit couples the single outdoor unit to the plurality of indoor units in parallel by liquid-side refrigerant piping and gas-side refrigerant piping, to form a refrigerating cycle of a heat pump type. The liquid-side refrigerant piping includes a motor-operated flow regulating valve and pressure reducer, which are connected in series fashion. A pseudo-refrigerant superheating state detector detects a pseudo-refrigerant overheating state on the basis of the temperature of the refrigerant in the aggregated portion of gas-side refrigerant piping of the distribution unit. A first controller respectively controls the open factors of the motor-operated flow regulating valves.

Abstract: A multi-type air conditioner has an outdoor unit, a plurality of indoor units, a refrigeration cycle, an inverter, flow control valves, opening/closing valves, a first controller, a second controller, and a third controller. The outdoor unit has a variable-capability compressor, an outdoor heat exchanger, and a pressure decreasing unit. Each indoor unit has an indoor heat exchanger. The refrigeration cycle has the variable-capability compressor, the outdoor heat exchanger, the pressure decreasing unit, and a parallel combination of the respective indoor heat exchangers connected in series. The inverter supplies drive power of a predetermined frequency to the capability variable compressor. The flow rate control valves are provided to the liquid-side refrigerant pipes of the respective indoor heat exchangers. The opening/closing valves are provided to the gas-side refrigerant pipes of the respective indoor heat exchangers.