WHERE CAN A DAVIDSON-HILL VENTURI TURBINE BE INSTALLED?

A Davidson-Hill Venturi Turbine (DHV) can be installed anywhere there is a fast moving body of water where the water is moving at 2 meters per second (walking speed) or more. For example in a fast flowing river where there is minimum turbulence – turbulence reduces the efficiency of the turbine – a fast moving tidal region such as the entrance to a bay or river, or between an island and the mainland to name a few. The possibilities are almost limitless.

HOW MUCH POWER CAN A DHV VENTURI TURBINE PRODUCE?

There are three factors that determine how much power any turbine can produce.

1. The speed or velocity of the moving water – the faster the water moves the more energy in the water that can be harvested.

2. The size of the turbine rotor – the bigger the turbine rotor the more energy that it can harvest from the moving water.

3. The efficiency of the turbine rotor – or the ability of the turbine to convert the energy in the moving water into mechanical energy in the form of a rotating shaft with the ability to do useful work – say drive a gearbox and generator or pump water etc.

HOW DO I MEASURE THE WATER FLOW SPEED (VELOCITY) AT MY LOCATION?

The simplest and easiest way to measure your water speed or velocity without any tools is the same method as what engineers have used for hundreds of years. It is still used today where sophisticated measuring equipment is not available or can not be installed. The more times you do this test, the more accurate the measurement becomes.

1. Pick a place where you can see the water is moving fast and measure out a ten meter distance on the bank.

2. Using a stop watch, time how long it takes for a floating object thrown into the water – a small twig or stick or anything that floats and is NOT going to harm the environment – to pass between the marks and cover the whole ten meter distance. Accuracy is important.

3. Repeat this as many times as possible.

4. Averaging the results – multiply 10 meters by the number of recorded events then add up all the times and divide the total distance in meters by the total time in seconds to give you an average time for the speed or velocity in meters per second (m/s).

5. i.e. 10 meters x 10 events   ÷ total seconds for 10 events - (lets say 50 seconds in total)

= 10 meters x 10 events ÷ 50 seconds

= 100 meters ÷ 50 seconds

= 2 meters in 1 second

or = 2 m/s

To be commercially viable Tidal Energy Pty Ltd recommends that your site have a minimum water speed or velocity of 2m/s.

HOW DO I SELECT A TURBINE THAT IS RIGHT FOR ME?

There are three basis factors to consider when choosing a turbine,

1. The speed or velocity of the moving water – the faster the water moves the more energy in the water that can be harvested.

2. The depth of the flowing water – whether river or tidal zone – the depth of water needs to be approximately twice the turbine rotor diameter and the width of the flow approximately four times the turbine rotor diameter.

3. The geology of the sea or river bed – whether sand, mud or rock will affect the amount of work and structure to hold the turbine in place.

If you are considering the installation of a turbine you should consult your engineer and your local regulatory body about details that may effect an installation in your location – or you can engage Tidal Energy Pty Ltd engineers, just ask us for a quote.

HOW MUCH DOES A TURBINE AND GENERATOR INSTALLATION COST?

The cost of a typical 1.5 meter diameter turbine and generator combination starts at AU$120,000 not including shipping. Bulk orders can significantly reduce this cost.

The cost of installing a turbine depends on the site conditions and how the turbine will be supported. For example if the turbine can be slung under an existing floating pontoon or jetty type structure this significantly reduces the cost installation of anchoring a turbine to a sea or river bed.

For further information about your site consult your engineer or ask Tidal Energy Pty Ltd for your nearest sales agent.

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