Abstract: A system for generating electrical energy for a submarine using ocean currents includes a turbine mounted to the exterior hull that is comprised of a rotor, impelled by the ocean current and drives rotation of a generator for generating electrical energy. The submarine is configured with a pair of selectively extendable braking panels on either side of the submarine's hull.

Abstract: A method and system of heating combustion air before the combustion air is received by a hot water or steam boiler. A solar panel oriented to receive radiant energy from the sun is used to heat a fluid. A circulating pump moves the hot fluid through a closed loop to a preheat exchanger that is located in the combustion air stream of the hot water or steam boiler. When the combustion air blower of the hot water or steam boiler is on, heat from the heated circulating fluid in the preheat exchanger is transferred to combustion air going through the preheat exchanger to the combustion air blower of the boiler and to the boiler.

Abstract: Heat from continuous blow down from a steam boiler is used to preheat boiler combustion air. Blow down from the steam boiler is fed through a flash tank and a 3-way valve to a liquid heat exchanger to heat a circulating liquid. The hot circulating liquid is fed to a preheat coil to heat combustion air for a steam boiler. A 3-way valve located between the flash tank and heat exchanger controls the flow of blow down to the heat exchanger. A temperature sensor which monitors the temperature of the circulating liquid controls the 3-way valve and a circulating pump moves the liquid around a closed loop. Motorized or variable frequency drive damper control the flow of air to the preheat coil and to the combustion air blower of the steam boiler.