GB2448721A - Compressed air tidal power generator - Google Patents

Abstract

A chamber 2 is attached to the seabed and used for tidal power generation. During the flood tide, sea water enters the chamber through a one-way valve 1, compressing the air in the chamber. The compressed air drives a turbine 5, controlled by valve 3. During the ebb tide, water can be allowed to leave the chamber via outlet valve 4. Several chambers 2 can be attached to each other at the same location, and may be recovered to the shore for maintenance.

Description

Tidal Power Generation Chamber This invention relates to a system to

generate electricity using tidal energy.

The tide holds enormous potential for energy generation, particularly in areas of high tidal variation.

Many methods of tidal power generation comprise of underwater mechanical devices, which are limited in several respects. Underwater mechanical devices, by the very nature of their construction (typically mild-steel), will suffer from corrosion, a major issue in the seawater environment. The Initial capital outlay and the ongoing maintenance costs are high given the need to frequently refurbish / replace components. As a result, many systems are not commercially viable due to an unfavourabte power output to cost ratio.

This Invention relates to a simple chamber and turbine which can be located in any tidal location.

It can be manufactured Inexpensively and has low ongoing costs as it does not rely on complex underwater components. It is of modular construction with modules being exchanged for example, during on-shore maintenance.

The system comprises of chamber which Is attached to the seabed. The chamber has a single inlet, via a simple one-way valve, an outlet controlled via a proportional valve to a turbine, and a return controlled via a simple on-off valve. The chamber is situated so the inlet, return and the bottom of the chamber are positioned just below the lowest tide limit. The outlet is situated above the high tide.

Several chambers can be attached to each other at the same location FIgure 1 shows a side-elevation of the unit at low tide FIgure 2 shows a side-elevation of the unit at high tide In figure 1 the inlet valve (1) allows flow into the chamber (2) as the tide rises. The outlet valve (3) regulates the pressurised air to operate the turbine. The return valve (4), when open, lets the water level fall from the high tide level back to the low tide level.

Low tide is the beginning of the generation cycle. In this state, inlet valve (1) lets water flow into the chamber, the outlet valve (3) is closed and the on-off valve (4) is open. As the tide begins to rise, the return valve (4) is closed. The water level rises with the tide and consequently the air pressure increases In the space above the chamber water level.

In figure 2 a state of high tide has been reached: the outlet valve (3) & return valve (4) are stili closed and the level inside the chamber equals high tide. At this point the air pressure in the space above high tide has increased to maximum. The outlet valve (3) is proportionally opened to allow a controfled depressurisation of the chamber, with the resultant air flow channelled through a suitable throttling device to a turbine (5). After the power generation phase, the return valve (4) is opened to allow the water level inside the chamber to return to low tide level: this is the end of the generation cycle.

Claims (3)

1. Claims 1. A unit for power generation through the compression of air

   through a vertical tidal movement within a chamber.
2. 2. A unit according to claim 1 where the water level inside the chamber is regulated by valves allowing return to low tide level.
3. 3. A unit according to claims I & 2 of modular construction allowing exchange of units for on-shore maintenance.