A propeller has a number of blade surfaces or winglets extending helically around its rotational axis in the most streamlined manner. The winglets gradually project at an increasing distance outward with an arcuate shape, each defining a rearwardly concave channel that increases in volume and degree of encirclement rearward on the propeller. In the front of the propeller, the winglets are shaped so that they have edges angled obliquely and diagonally that conformingly and without cavitation cut into the water and cause it to flow smoothly in the channels. In the middle of the propeller, the winglet edges extend rearward so that water entrained in the channel is directed rearward without centrifugal loss. In the rear portion of the propeller, the channels narrow and reduce in volume so as to expel the water from the concavity.

An apparatus includes one or more thermal storage blocks that define a radiation chamber and a fluid flow slot positioned above the radiation chamber to define a fluid pathway in a first direction. The apparatus includes a heater element positioned adjacent to the radiation chamber in a second, different direction, wherein the radiation chamber is open on at least one side to the heater element. The apparatus includes a fluid movement system configured to direct a stream of fluid through the fluid pathway in the first direction.

An energy storage system converts variable renewable electricity (VRE) to continuous heat at over 1000? C. Intermittent electrical energy heats a solid medium. Heat from the solid medium is delivered continuously on demand. An array of bricks incorporating internal radiation cavities is directly heated by thermal radiation. The cavities facilitate rapid, uniform heating via reradiation. Heat delivery via flowing gas establishes a thermocline which maintains high outlet temperature throughout discharge. Gas flows through structured pathways within the array, delivering heat which may be used for processes including calcination, hydrogen electrolysis, steam generation, and thermal power generation and cogeneration. Groups of thermal storage arrays may be controlled and operated at high temperatures without thermal runaway via deep-discharge sequencing. Forecast-based control enables continuous, year-round heat supply using current and advance information of weather and VRE availability. High-voltage DC power conversion and distribution circuitry improves the efficiency of VRE power transfer into the system.

An energy storage system converts variable renewable electricity (VRE) to continuous heat at over 1000? C. Intermittent electrical energy heats a solid medium. Heat from the solid medium is delivered continuously on demand. An array of bricks incorporating internal radiation cavities is directly heated by thermal radiation. The cavities facilitate rapid, uniform heating via reradiation. Heat delivery via flowing gas establishes a thermocline which maintains high outlet temperature throughout discharge. Gas flows through structured pathways within the array, delivering heat which may be used for processes including calcination, hydrogen electrolysis, steam generation, and thermal power generation and cogeneration. Groups of thermal storage arrays may be controlled and operated at high temperatures without thermal runaway via deep-discharge sequencing. Forecast-based control enables continuous, year-round heat supply using current and advance information of weather and VRE availability. High-voltage DC power conversion and distribution circuitry improves the efficiency of VRE power transfer into the system.

An energy storage system converts variable renewable electricity (VRE) to continuous heat at over 1000? C. Intermittent electrical energy heats a solid medium. Heat from the solid medium is delivered continuously on demand. An array of bricks incorporating internal radiation cavities is directly heated by thermal radiation. The cavities facilitate rapid, uniform heating via reradiation. Heat delivery via flowing gas establishes a thermocline which maintains high outlet temperature throughout discharge. Gas flows through structured pathways within the array, delivering heat which may be used for processes including calcination, hydrogen electrolysis, steam generation, and thermal power generation and cogeneration. Groups of thermal storage arrays may be controlled and operated at high temperatures without thermal runaway via deep-discharge sequencing. Forecast-based control enables continuous, year-round heat supply using current and advance information of weather and VRE availability. High-voltage DC power conversion and distribution circuitry improves the efficiency of VRE power transfer into the system.

A water turbine propeller includes an optional turbine casing having forward and rearward openings, a rotational cylindrical unit, a plurality of rotating foil blades rigidly secured to the inner periphery of the rotational shaft on a common shaft, and an engine or motor which rotates the rotational shaft within the turbine casing. The operation of the engine causes the rotation of the rotational shaft and the helical blades direct water into the forward opening of the turbine casing and out the rearward openings of the turbine casing, thereby creating a focused torque (or vortex) effect on the water flow for a propulsive force.

A water turbine propeller includes an optional turbine casing having forward and rearward openings, a rotational cylindrical unit, a plurality of rotating foil blades rigidly secured to the inner periphery of the rotational shaft on a common shaft, and an engine or motor which rotates the rotational shaft within the turbine casing. The operation of the engine causes the rotation of the rotational shaft and the helical blades direct water into the forward opening of the turbine casing and out the rearward openings of the turbine casing, thereby creating a focused torque (or vortex) effect on the water flow for a propulsive force.

A robotic device for inspecting a pipe includes at least one pair of propulsion elements each including a rotary drum, an outer surface of which has a screw thread. The device also includes a body associated with at least one pair of propulsion elements and in which are inserted sensor, at least one pair of electric motors each capable of rotating a rotary drum, and at least one pair of electric power sources each capable of powering an electric motor. The body is shaped such that a ventral portion and a dorsal portion of the device are symmetrical with one another relative to a median frontal plane of the device, thus allowing the device to move indistinctly on the belly or on the back.

A robotic device for inspecting a pipe includes at least one pair of propulsion elements each including a rotary drum, an outer surface of which has a screw thread. The device also includes a body associated with at least one pair of propulsion elements and in which are inserted sensor, at least one pair of electric motors each capable of rotating a rotary drum, and at least one pair of electric power sources each capable of powering an electric motor. The body is shaped such that a ventral portion and a dorsal portion of the device are symmetrical with one another relative to a median frontal plane of the device, thus allowing the device to move indistinctly on the belly or on the back.

A robotic fish comprises one or more torque reaction engines and a fish body, wherein the torque reaction engine cyclically oscillates and causes a wave to propagate across the fish body, including through a flexible wing, accelerating thrust fluid and propelling the robotic fish.