GB2301633A

GB2301633A - Electric Power Generation

Info

Publication number: GB2301633A
Application number: GB9511042A
Authority: GB
Inventors: Gordon Cross
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-06-01
Filing date: 1995-06-01
Publication date: 1996-12-11
Anticipated expiration: 2015-06-01
Also published as: GB9511042D0; GB2301633A8; GB2301633B

Abstract

A well or shaft (10) of a depth extending to at least 500m, and preferably over 1,000m, below ground level communicates at or near its base with at least one air flow passageway (12) of similar depth. A down draught of air is created through the shaft (10), for example, by means of a sprinkler system (16) mounted above it, and consequent upflow of air through the passageway(s) (12) may be assisted by arranging heating means (18) near the top of the passageway(s). The air issuing from the top of the or each passageway is directed through a turbine (14) so as to generate electricity.

Description

Electric Power Generation This invention concerns an air-powered electricity generating system.

The object of the invention is to provide a novel means of producing electricity which avoids combustion of fossil fuels or other exhaustible fuel supplies and also avoids generation of pollutants.

The invention provides apparatus for generating electricity comprising a well or shaft of a depth extending to at least 500m below ground level in communication at or near its base with at least one air flow passageway of similar depth, means for creating a downdraught of air through the shaft and an upward flow of air through the or each passageway, and a turbine arranged to receive air issuing from the top of the or each passageway.

An exemplary embodiment of the invention will now be described with reference to the accompanying drawings, in which: Fig 1 is a schematic longitudinal cross section through the apparatus; Fig 2 is a transverse cross section of the shaft at a position intermediate ground level and its base; and Fig 3 is a partial plan view of an alternative embodiment of the apparatus.

It is proposed that in order to construct apparatus in accordance with the invention use is made of a disused mine shaft of suitable depth and diameter. In this respect a depth of at least 500m, and preferably over l,OOOm, is desirable in order to create an adequate pressure of air to drive the turbines. Such a shaft is designated by reference (10) in the drawings.

Essentially, the proposal is that a down draught of air should be created in a central region of the shaft (10), followed by an upward flow of that air though one or more relatively narrow tubes (12) mounted around the periphery of the shaft (10), the air then being supplied from the top of these tubes to drive turbines (14) situated at ground level.

The means proposed to promote the central down draught is a sprinkler system (16) mounted above the opening of the shaft (10) and extending over the majority of the area of that opening. The system (16) may comprise a disc or spoked wheel arrangement carrying a plurality of fine nozzles or other outlets over its lower surface so as to direct a plurality of fine jets of liquid, usually water, downwards into the shaft (10), this liquid entraining air to flow downwards also, as shown. Also promoting the central downdraught, as well as the upf low of air in the tubes (12), four of which are shown in the illustrated embodiment, are heating means (18) mounted within said tubes (12). The heating means (18), which may comprise conventional heating elements, need not be operational throughout the entire time electricity is to be generated.Once the desired air flow pattern is established, they can be switched off to save energy.

The upf low of air in the peripheral tubes (12) is essential to the invention and in this respect the suction force exerted by the heating means (18) is very important in drawing air up from the bottom of the shaft.

To facilitate the flow of air in a smooth path (ie without excessive eddies and vortices which deplete it of energy), a large diameter tube (20) having a smooth inner surface is advantageously mounted into the shaft (10), to serve as a lining thereto, as best shown in Fig 2. The upflow tubes (12) then surround the lining tube (20), and the sprinkler system (16) is dimensioned to spray the liquid into the central area delimited by the tube (20).

A further measure to promote the desired air flow path, and particularly to assist the change in direction of the air at the base of the shaft, is provision of a large cone (22) in the base of the shaft (10). The cone (22) may, for example, have a basal diameter about 1.25m less than the lining (20).

Also, the upf low tubes (12) are all somewhat tapered in an upward direction so as to increase the air velocity and air pressure as it moves towards the top. The diameter of these tubes (12) may diminish to as little as 15 cm at the top.

A sump and a pump are also provided at the base of the shaft (10), as indicated generally by reference numeral (24), in order to collect the water from the sprinkler system (16) and return it to the surface for re-use.

Variations are, of course, possible, within the scope of the appendant claims. Figure 3 shows a variant wherein the tubes (12) are not separate components of circular cross section, but are formed on the outside of the lining (20), each extending around 25% of the circumference of the lining (20) and being of a flattened or elongate shape in cross section. However, they still advantageously taper towards the top of the shaft.

Claims

1. Apparatus for generating electricity comprising a well or shaft of a depth extending to at least 500m below ground level in communication at or near its base with at least one air flow passageway of similar depth, means for creating a down draught of air through the shaft and an upward flow of air through the or each passageway, and a turbine arranged to receive air issuing from the top of the or each passageway.

2. Apparatus as claimed in claim 1 wherein the means for creating a downdraught of air in the shaft comprises a sprinkler system mounted at or near the top of the shaft and adapted to spray water downwards into the shaft.

3. Apparatus as claimed in claim 1 or 2 wherein the means for creating an upward flow of air in the or each passageway comprises heating means disposed in the upper region of the or each passageway.

4. Apparatus as claimed in any preceding claim wherein the or each air flow passageway tapers in an upward direction.

5. Apparatus as claimed in any preceding claim wherein a plurality of air flow passageways are provided in the form of elongate tubes arranged substantially equidistantly around the periphery of a main shaft.

6. Apparatus as claimed in claim 5 wherein a conical formation is provided at the centre of the base of the main shaft in order to direct air flow into the base of the tubes.

7. Apparatus for generating electricity substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.