Abstract
The Wave Dragon is a floating slack-moored Wave Energy Converter (WEC) of the overtopping type. Oncoming waves are focused by two wing reflectors towards the ramp of the device, surge-up and overtop into a reservoir placed at a higher level than the surface of the sea. The energy production takes place as the water is led back to the sea through a set of low-head hydro-turbines. After many years of development, Wave Dragon (WD) is now facing the phase of pre-commercial demonstration. In this phase it is very important to be able to use the available data to predict the performances of the device at different scales and locations. A flexible and comprehensive modelling tool is therefore highly required.
Wave Dragon produces power through different steps of energy conversion:
1. Primary energy conversion: overtopping – The energy content of the wave (partly in the kinetic and partly in the potential form) is transferred to the device in the form of volumes of water coming into the reservoir. These volumes are stored at a higher level than the surrounding sea, being a stock of potential energy.
2. Secondary energy conversion: turbines – The potential energy stored in the reservoir is transformed into mechanical energy as the water flows back to the sea, activating the lowhead hydro-turbines.
3. Tertiary energy conversion step: generators – The turbines shaft rotation activates the permanent magnet generators, converting mechanical energy into electrical energy.
4. Grid connection and delivery of the power – The electricity produced is delivered to the grid at the right frequency, by means of a frequency converter.
The present research is focused on the overtopping. Being the primary energy conversion mechanism of the WD, the overtopping is indeed the stage where the performances of the device are influenced by local conditions and the geometric features of the set-up. This makes it the right step where to account for these features through an accurate modelling.
Wave Dragon produces power through different steps of energy conversion:
1. Primary energy conversion: overtopping – The energy content of the wave (partly in the kinetic and partly in the potential form) is transferred to the device in the form of volumes of water coming into the reservoir. These volumes are stored at a higher level than the surrounding sea, being a stock of potential energy.
2. Secondary energy conversion: turbines – The potential energy stored in the reservoir is transformed into mechanical energy as the water flows back to the sea, activating the lowhead hydro-turbines.
3. Tertiary energy conversion step: generators – The turbines shaft rotation activates the permanent magnet generators, converting mechanical energy into electrical energy.
4. Grid connection and delivery of the power – The electricity produced is delivered to the grid at the right frequency, by means of a frequency converter.
The present research is focused on the overtopping. Being the primary energy conversion mechanism of the WD, the overtopping is indeed the stage where the performances of the device are influenced by local conditions and the geometric features of the set-up. This makes it the right step where to account for these features through an accurate modelling.
| Originalsprog | Engelsk |
|---|
| Udgivelsessted | Aalborg |
|---|---|
| Forlag | Department of Civil Engineering, Aalborg University |
| Antal sider | 42 |
| Status | Udgivet - 2011 |
| Navn | DCE Technical reports |
|---|---|
| Nummer | 109 |
Bibliografisk note
PDF for print: 48 pp.Emneord
- Wave Dragon
- Wave Energy Converters
- Overtopping
- Experimental Modelling