The invention concerns a removable cover plate (160) for an inter-blade profile (14, 14a) of a turbine runner blade, said cover plate comprising at least one aeration passage (30) and securing means (161) for securing said removable cover plate onto said inter-blade profile (14).

A data center is cooled by a cryogenic cooling system which is wind driven, and powered by energy stored in the cryogenic liquid. The cooling occurs through downwardly passing cryogenic liquid which is recycled and pushed back to a top of a system in a cyclic manner.

A hydroelectric turbine installation includes a turbine, a water passage located upstream, a draft tube, a controller that controls operation conditions, a device for introducing oxygen-containing gas into water passing through the installation, a device for injecting water into the draft tube, and a device for controlling a flowrate of the water injected into the draft tube. The device for controlling the flowrate includes a control unit and a valve. The control-unit is configured to control the flowrate of the water injected into the draft tube in a way that the flowrate is a function of the operation conditions of the turbine. The flowrate set by the control unit at an operation condition of the turbine corresponding to an optimal efficiency point of the turbine is higher than a flowrate set by the control-unit at one or more other operation conditions of the turbine that do not correspond to an optimal efficiency point.

The invention relates to a heat exchanger for an electrical machine. The heat exchanger comprises a housing and a tube bundle. The tube bundle comprises a plurality of tubes within the housing extending between a first end and a second end of the housing in the direction of the length of the heat exchanger. The housing comprises a top wall, end walls extending in the direction of the width of the heat exchanger and first and second side walls extending in the direction of the length of the heat exchanger and a bottom frame. Between a first side wall of the housing and a side of the tube bundle is a mounting space for receiving one or more cooling fluid circulating devices.

Aerating system for the runner of a hydraulic turbine, the runner comprising a plurality of blades, such that inter-blade canals are configured between each pair of blades for the admission of air in the water flow circulating through the hydraulic turbine, such that the aerating system comprises at least one hydrofoil located in the inter-blade canal of the runner contacting the pair of blades configuring the inter-blade canal where the hydrofoil is located, such that the hydrofoil has a non-axis symmetrical profile, and such that at least one of the blades in contact with the hydrofoil comprises an aerating canal delivering air to the hydrofoil.

A venting apparatus for generating electricity, the apparatus comprising a head and a base, whereby rotation of the head relative to the base generates electricity, wherein the head includes: a receptacle in which is disposed a solar cell, and a plurality of blades disposed around a periphery of the head for rotating the head in response to airflow around and/or over the head.