I'm currently assessing sub sea pumped hydro capabilities, and need to use the flow rate in order to calculate power output. I can calculate the energy storage capacity using E = mgh:
$E=mgh = 25675000 \times 9.81 \times 200 = 50374 \ \mathrm{MJ} = \frac {50374\text{MJ}}{3600} = 13992 \ \mathrm {kWh}$
However, I don't know what the flow rate from open sea into the pipe would be. In the model below, the top of the pipe has a valve that will open to let seawater in during the power generation stage, down through a 90/10 Cu/Ni pipe, through a turbine and subsequently fill up the vessel, which is located 200 m below the inlet (Head = 200 m). Vessel design doesn't take into account the pressure at this depth through use of a bag seen here.
What would the best way to calculate the flow rate to use in theoretical power calculations, since the sea is an open reservoir?
- Head = 200 m
- Pipe Length = 1594m (assuming a straight path between elevations)
- Vessel Volume = 25,000 m3
- Seawater Density = 1027 kg/m3
These variables can all be changed this is just preliminary/theoretical.