Abstract: A system for charging the battery and operating the electrical accessories of a sail-boat is disclosed. The system comprises an alternator having a stator winding adapted for connection to the battery through suitable current rectifiers and a rotor field winding coupled to the auxiliary propeller shaft of the boat. Circuit means for controlling the energization of the field winding of the alternator from the output voltage of the stator winding, so as to permit the alternator to provide adequate current to charge the battery and operate the electrical accessories of the sail-boat, and a voltage regulator adapted for connection to the field winding of the alternator for controlling the output voltage of the stator winding when such output voltage reaches a predetermined value.

Abstract: A ground heat exchanger adapted to be buried in the ground and to be used in association with a heat pump system for heating and cooling. The exchanger includes a heat conducting metal plate adapted to be vertically buried in the ground and carrying a fluid circulating coil adapted to be connected to the circuit of the heat pump system. The ends of the plate are each movably inserted into a corresponding slit of an upright tube filled with a heat conducting grease. Weights compress the grease within the tubes and cause its ejection through apertures of the tubes along both surfaces of the plate, so as to fill any voids between the plate and the ground and to also fill any new voids which may develop due to contraction of expansion of the plate with temperature variation and also due to ground movement. The top ends of the tubes are accessible above ground surface, so that they may be refilled according to need.