A solar energy powered Stirling duplex cooler is presented which includes a Stirling engine and a Stirling cooler. The Stirling engine drives the Stirling cooler to produce cold temperatures for refrigeration or air conditioning. The Stirling duplex cooler includes a solar concentrator to focus high temperature solar radiation upon the Stirling engine expansion space. The Stirling duplex cooler further includes a thermal storage tank to receive and store heat rejected from the cooler expansion space. This stored heat is used to operate the cooler at night. A flywheel connected operatively to engine and cooler expansion space pistons and a crankshaft connected operatively to engine and cooler compression space pistons actuate the pistons to move a working fluid between the expansion and compression spaces.

A heat transfer device (100) includes an inner tube (102) mounted within a tubular chamber (104) of a heat exchanger (106). The hollow tubular chamber (104) has a closed end (108) with inwardly sloping inner surfaces (110) and the inner tube (102) has an open end (112) that terminates short of the closed end (108). A diffuser (114) is provided and is shaped such that an operatively front part (116) thereof substantially conforms to a shape of the inner surfaces (110) of the closed end (108) so as to form a narrow flow passageway (118) between the diffuser (114) and the inner surfaces (110) at the closed end (108), and an operatively back part (120) of the diffuser (114) slopes towards the inner tube (102) and away from its open end (112) to form a diffusion zone (122). Heat transfer assemblies utilising the heat transfer device (100) are also disclosed.

A heat transfer device (100) includes an inner tube (102) mounted within a tubular chamber (104) of a heat exchanger (106). The hollow tubular chamber (104) has a closed end (108) with inwardly sloping inner surfaces (110) and the inner tube (102) has an open end (112) that terminates short of the closed end (108). A diffuser (114) is provided and is shaped such that an operatively front part (116) thereof substantially conforms to a shape of the inner surfaces (110) of the closed end (108) so as to form a narrow flow passageway (118) between the diffuser (114) and the inner surfaces (110) at the closed end (108), and an operatively back part (120) of the diffuser (114) slopes towards the inner tube (102) and away from its open end (112) to form a diffusion zone (122). Heat transfer assemblies utilising the heat transfer device (100) are also disclosed.

A supporting and handling system for optical devices, in particular telescopes, radio-telescopes or sun concentrators, and instrumentation, is described, comprising: a primary unit; an independent secondary unit; first motored means for moving the primary unit; second motored means for moving the secondary unit; an arc-shaped structure equipped with sliding guides in altitude with respect to the ground for the rotation of the secondary unit with respect to an altitude rotation axis; a hexapod system to move the primary unit; and a control system.

Various implementations include solar thermal energy collection system comprising a solar energy concentrator, a heat transfer fluid, an absorber pipe. The absorber pipe includes a pipe wall and has a central longitudinal axis. The pipe wall has an inner surface and an outer surface. The inner surface has a first contour defining alternating peaks and troughs along a length of the absorber pipe. The outer surface has a second contour defining alternating peaks and troughs along the length of the absorber pipe. The inner surface defines the entire flow path for the heat transfer fluid through the absorber pipe. The first contour, as viewed through an axial cross section of the absorber pipe, forms sinusoidal waves on each side of and spaced apart from the central longitudinal axis. The sinusoidal waves on each side of the central longitudinal axis are symmetrical with respect to the central longitudinal axis.

Various implementations include solar thermal energy collection system comprising a solar energy concentrator, a heat transfer fluid, an absorber pipe. The absorber pipe includes a pipe wall and has a central longitudinal axis. The pipe wall has an inner surface and an outer surface. The inner surface has a first contour defining alternating peaks and troughs along a length of the absorber pipe. The outer surface has a second contour defining alternating peaks and troughs along the length of the absorber pipe. The inner surface defines the entire flow path for the heat transfer fluid through the absorber pipe. The first contour, as viewed through an axial cross section of the absorber pipe, forms sinusoidal waves on each side of and spaced apart from the central longitudinal axis. The sinusoidal waves on each side of the central longitudinal axis are symmetrical with respect to the central longitudinal axis.

A novel portable solar energy system includes a solar concentrator, a thermal storage device, an azimuth adjustment system, an elevation system, and a heat exchanger, all mounted on a rotatable support frame. In a particular embodiment, the thermal storage device remains at a fixed vertical height and fixed tilt orientation when adjustments are made to the azimuth adjustment system and/or the elevation adjustment system.

A novel portable solar energy system includes a solar concentrator, a thermal storage device, an azimuth adjustment system, an elevation system, and a heat exchanger, all mounted on a rotatable support frame. In a particular embodiment, the thermal storage device remains at a fixed vertical height and fixed tilt orientation when adjustments are made to the azimuth adjustment system and/or the elevation adjustment system.

The disclosure relates to a method for producing a dimensionally stable concrete work-piece characterised in that to produce the concrete work-piece a fully-sealed dimensionally stable form is filled with fresh concrete in a predetermined geometry, during the subsequent and undisrupted hydration a predetermined temperature distribution of the walls of the form surrounding the hydrated concrete is carried out and the concrete workpiece is shaped at a compressive strength of more than 10 MPa.

A transportation network for providing propellant in space can include optical mining vehicles that concentrate solar energy to spall captured asteroids, capture released volatiles, and store them in reservoirs as propellants. The network can also have orbital transfer vehicles that use solar thermal rocket modules that focus solar energy on heat exchangers to force propellant through nozzles, as well as separable aeromaneuvering tanker modules with reusable heatshields and storage tanks. The network can have propellant depots positioned between Earth and a transport destination. The depots can mechanically couple to accept propellant delivery and to supply it to visiting space vehicles.