The Ukrainian researchers of Nizhyn Labs of Scanning Devices (NLSD), directed by Vasil Sidorov, electrical and optical engineer and candidate of technical sciences, are working on development of new molecular methods and systems of direct receipt of electrical energy from moving water using electrokinetic phenomena.

Electrokinetic methods and devices for extraction of energy of moving water are based on the electrokinetic effect, arising up in the dispersive systems. This effect is expressed in appearance of difference of potentials in direction of relative motion of phases under action of mechanical forces.

The algorithm of electrokinetic method of electric current production consists of a few stages. On the first stage kinetic energy of atoms and molecules of water is transformed into kinetic energy of electrolyte which moving through porous body (through a capillary) or relative to flat surface under pressure forms streaming potential. A source of all these effects - the interfacial 'double layer' of charges.

A double layer (DL, also called electrical double layer, EDL) is a structure that appears on the surface of an object when it is placed into a liquid. This object might be a solid particle, or gas bubble, or liquid droplet, or porous body. This structure consists of two parallel layers of ions. One layer (either positive or negative) coincides with the surface of the object. It is surface charge. The other layer is in the fluid. It electrically screens the first one. It is diffuse, because it forms under the influence of electric attraction and thermal motion of free ions in fluid. It is called the diffuse layer.

Interfacial DL is usually most apparent in systems with high surface area. This might be colloids with very small sizes, on the scale of a micrometer or even nanometers. Porous bodies with small size of pores on the same scale are another example. However, the importance of DLs extends to other systems, e.g., DL is fundamental to the electrochemical behavior of electrodes. This process leads to the build up of an electric surface charge, expressed usually in C/m². This surface charge creates an electrostatic field that then affects the ions in the bulk of the liquid. This electrostatic field, in combination with the thermal motion of the ions, creates a counter charge, and thus screens the electric surface charge. The net electric charge in this screening diffuse layer is equal in magnitude to the net surface charge, but has the opposite polarity. As a result the complete structure is electrically neutral. Some of the counter-ions might specifically adsorb near the surface and build an inner sub-layer, or so-called Stern layer. The outer part of the screening layer is usually called the diffuse layer

The DL is closely related to electrokinetic phenomena. Various combinations of the driving force and moving phase determine various electrokinetic effects. The group of electrokinetic phenomena includes: electrophoresis (motion of particles under influence of electric field); electro-osmosis (motion of liquid in porous body under influence of electric field); sedimentation potential (electric field generated by sedimenting colloid particles); streaming potential/current (electric potential or current generated by fluid moving through porous body);

The charges appeared on the phases boundary are accumulated in future and used to form of electric current.

A chart of electrokinetic power system concludes a working body (water), electrokinetics cell, accumulator of charges and inverter.

Moving water (molecules) passes the kinetic energy as pressure to electrolyte of electrokinetic cell. Electrolyte when going under pressure through electrokinetic cell capillaries forms on the boundary of phases a streaming potential. Charges arising up in a double layer are accumulated and given to inverter to form an industrial current suitable for consumption. 

Structurally the electrokinetic cell consists of two identical chambers 1 and 2, one of which in the initial state is filled by an electrolyte, capillary system, systems of electrodes and systems of knocking over (trigger). Sylphon type chambers 1 and 2 can change an internal volume under pressure of moving water on their external walls.

The electrokinetic cell works as follows. In initial position an electrolyte is found in a chamber 1. In the absence of dynamic water pressure the static pressure operates on external walls A1 and A2 accordingly of chambers 1 and 2. An electrolyte from a chamber 1 does not flow out. Electric potential on electrodes is equals a zero.

After electrokinetic cell is placed in the stream of water so that the vector of speed of stream is directed along the axis of an electrokinetic cell, athwart to the external wall A1 of chamber 1. At appearance of water pressure on the external wall A1 of the chamber 1 the action of two forces appears - static pressure P_st and dynamic pressure R_d of a mobile water. Under action of dynamic pressure a chamber (volume) 1 compresses and changes (toward reduction) the internal volume. An electrolyte under action of pressure is moving from a chamber 1 through the capillary system into a chamber 2. As a result on the output of the capillary system a double electric layer appears that can be observed as an electric current on the electrokinetic cell electrodes, when loading resistance is connected to the electrodes.

After the devastation of chamber 1 an «inverting» trigger system under action of water pressure revolves electrokinetic cell round it center of the masses so that begins water pressure is perceived by the external wall A2 of a chamber 2. In this case the process of pumping of electrolyte begins from a chamber 2 in a chamber 1. Depending on the choice of type of electrolyte and electrodes it is possible to get streaming potential of opposite sign on an electrode.

 For the increase of efficiency and electric power the electrokinetic cells can be grouped in a matrix. Electrokinetics molecular matrix consists of the N rows and M term of elementary cells. The use of the system of charge transfer allows taking off an electric current consistently from each cell with necessary frequency and parameters.  

Molecular matrices can be made with a different number of elements and, accordingly, different sizes, depending on concrete aims and terms of the use.

Matrices also can be easily united in the systems of different sizes (sectional matrices) for the receipt of considerable electric power.

At making of molecular electrokinetic matrices the technologies that are used in production of integral electronic devices can be used, for example plasma panels or liquid-crystal panels. It will reduce a cost and provide high quality that is achieved at mass production.

By Vasil Sidorov on March 07, 2009   in queltanews.com