Abstract: A heating and/or air-conditioning installation with a motor-driven fan unit has a motor driving a turbine, a speed control module and a volute housing the motor and forming an outlet channel for airflow at the periphery of the turbine. The speed control module is mounted at the periphery of the motor and has an electrical connector engaging a connector of the motor. It also has one or more walls of thermally conducting material and in contact with the outlet channel to cool the module.

Abstract: In a variable displacement compressor of the invention, cylinder bores (111) and a crankcase (121) are formed in a housing, single-ended pistons (37) are fitted in the cylinder bores (111), and a cam plate (23) is provided in the crankcase (121). The displacement capacity of the compressor is varied by controlling the angle of inclination of the cam plate (23) in accordance with the difference between the internal pressure of the crankcase (121) and an suction pressure present on both sides of each single-ended piston (37). A dampening or muffler chamber (65) is provided downstream of an output channel (114) through which a refrigerant gas discharged from the cylinder bores (111) passes. A check valve (69) which opens and closes in accordance with a pressure difference between upstream and downstream sides of the output channel (114) is provided in the output channel (114), upstream of the muffler chamber (65).