ECS: Has it been independently verified?
There is a strong negative bias amongst academics, scientists and engineers that because no one has yet succeeded in converting g-force into useful power, it is impossible and therefore can never be done.
I realised early on that an independent validation of ECS was going to be necessary, so I commissioned TUV-NEL, a leading firm of hydrodynamic consultants, to carry out a detailed investigation into my design of a small 30kW ECS unit.
TUV are a large international company who took over the UK’s National Engineering Laboratory in 1995. For details of the company and the specialist consultancy services they offer see www.tuvnel.com
TUV-NEL staff completed a ‘desk top’ study of my 30KW pilot ECS design and their report gives a very detailed analysis of the inter-flowing ECS circuits on page 19.
Gross power outputs of 44.87KW are given on page 21 with a calculated net export power of 33.8KW on page 7, after deductions of the operational power requirements.
Their analysis confirms the accuracy of my original design and provides full verification of it.
TUV-NEL staff were offered the opportunity to witness the Proof of Concept (PoC) ECS unit in operation, but declined and instead included the following caveats in the ‘Conclusions’ section of their report.
Caveat 1. The current verification is based on ‘steady state’ hydrodynamic models; however, the system is inherently transient in nature and would benefit from ‘unsteady’ calculations. In particular the system losses in key areas such as the rising and falling of water in the Back Up (BU) tanks, alongside the ‘back up phenomena’ witnessed on the PoC would be advantageous to understand mathematically.
Comment:- The following video demonstrates this rising and falling ‘Back Up’ action on a 60 second cycle, when operating in HAC mode, the range within the back up tanks is minimal in relation to the 35m height of the system. The PoC is fitted with instruments which provide robust data for mathematical analysis.
Caveat 2. The hydrodynamic calculations of the components which can be verified include the selection of the pump and suitable base pressure to move the dense media from the manifold tank through the system to the back-up tanks at a height of 35m. However, the pressure in the downward media pipe is lower than the manifold tank preventing the media to flow back into the tank. During small scale testing by Associated Power, a ‘back-up’ phenomenon was observed where media would mix in the back-up tanks and allow the media back into the manifold tank. This phenomenon would benefit from 3D CFD modelling analysis and small-scale experiments with pressure measurements to derive a suitable verified model.
Comment:- TUV-NEL repeatedly state that ECS is transient in nature, not steady state. The downflowing mixture of dense media and water can continuously enter the manifold tank, because the tank is being drained at exactly the same rate by the combined action of the circulation pump and feed to the magnet. This phenomenon can be observed in continuous action on the PoC.
The operation of the back-up tanks is fundamental to the generation of export power from ECS units, as TUV-NEL acknowledge in their verification of the 30KW pilot unit.
Caveat 3. The base pressure is also sufficient to move the media through the magnet and turbine to the back up tanks, however, this assumes minimal loss of head pressure through the magnet. As the magnet is a novel technology developed by Associated Power Ltd, further experimental data is required to build a suitable model at the scale and efficiency required for this system.
Comment:- The layout of the magnet system in the PoC now differs from the TUV-NEL diagram shown on page 18 of their report. Associated Power originally operated the rotating drum, partially submerged, in the horizontal position, as depicted in their diagram, however, to minimise drag losses the drum is now mounted vertically inside an airlock, rotating in air, with negligible resistance, within the magnet tank. A diagram of this revised layout can be viewed at ECS Technology - How it works.
Large permanent ferrite magnets are incorporated in the s/s drum, hence no exterior power is required for the magnet element.
Manifold tank pressure is used to raise media to the upper level of the rotating drum, where it is discharged under gravity onto the drum for virtually complete separation of the media from the water.
The drum is mounted on ball bearings and can easily be rotated, fully loaded with media, by hand. No discernible difference in the current drawn by the small, electrically operated hydraulic pump, was observed between the drum rotating empty or fully loaded. This fact gives confidence that separation of media from water can be achieved, at scale, with minimal power.
Caveat 4. Overall, the ECS requires additional modelling to ensure the system can work continuously. As the system is inherently transient, unsteady simulations, such as CFD or process modelling can be used. It is recommended that calculations are first verified by experiment on a small-scale model similar to the facility previously built by Associated Power Ltd. Instrumentation such as pressure transducers should be placed throughout the system to provide data for validation of calculations and to aid the development of bespoke models for this system.
Comment:- The PoC has frequently been operated for many hours at a time, its ability to operate continuously cannot be questioned. TUV-NEL are correct in pointing out that the complex interflows of the ECS are inherently transient. Any attempt to model these interflows using only conventional steady state models will result in wrong conclusions being drawn. As stated the PoC is instrumented, but additional transducers can be fitted if required.
Please watch the following short video to see the back-up tanks on the PoC in action, in HAC mode.