An artificial reef to be anchored to the seabed comprises two or more juxtaposed conduits which are positioned in parallel with the direction of wave propagation. Both conduits include directrices. The upper conduit includes directrices which drive the flow of the wave's crest, and the lower conduit includes directrices which drive the water diverging from the apertures in the area under the wave's trough. The upper and lower conduits are hydraulically connected, each connection comprising a shut-down valve associated with a useful energy-generating unit.

An artificial snow-making facility includes: a snow-making device; a fluidic water pipe for supplying water to the snow-making device; potentially, a fluidic air pipe for supplying air to the snow-making device; a controller for managing the operation of the snow-making device; and a power supply for supplying electricity to the controller. The power supply includes a power generator arranged on one of the fluidic pipes, which power generator includes a turbine adapted to be driven by the fluid of the fluidic pipe.

A compressor having a housing along with a wheel including a hub and a plurality of impellers defining flow channels is disclosed. The hub forms a flow surface that defines a concave surface-curve from an inducer end to an inflection point, and a convex surface from the inflection point to an exducer end of the flow surface. The hub forms a back-disk surface including a circumferential edge-channel inset from and surrounding a central portion. The housing includes a conical inner-diffuser wall surrounding a circular inset wall. The central portion of the back-disk surface is received by the conical inner-diffuser wall, while the exducer end of the flow surface extends radially outward to be axially over an inner portion of the inner-diffuser wall.