FIELD OF THE INVENTION

The invention disclosed in the present patent application relates to the field of Energy and Electricity. Herein, it is described an innovative way for storage the energy by a new thermomechanical energy storage system that is engineered from renewable natural, readily biodegradable, or recyclable materials that are also reusable. The enclosed system can sustainably operate for higher-than-usual volumes of energy storage and for longer-than-usual storage time (long-term storage). It is also characterized with a low-carbon footprint for its production and no chemical footprint when operating or being disposed-off at the end of its life cycle.

Technical problem resolved by the invention

By a rightful combination of mainly natural materials coupled with thermo-mechanical processes, the invention enclosed in the present patent application resolves technical problems well known in the current state of the art:

Namely, today, renewable energy, mainly generated by solar, wind and hydropower sources, provides more sustainable generated energy alternative as the humanity attempt to decarbonize the society. In the current state of the art, due to limited or non-cost-effective types of storage possibilities available, the problem arises when this energy has to be stored, whereby large part of the generated energy ends irreversibly lost. When the invention is in operation, very little generated energy is lost.

The thermo mechanical system provides a solution for energy storage for 5-7 days, which classifies this invention as a long-term ESS (Energy Storage Systems) and thus can provide for more efficient storage conditions but also cheaper end-price energy. Due to its long-term storage capacity, the invented system provides energy "where needed, when needed”.

The following patented inventions are known to the applicant of the current patent application: - US11 , 391 ,18182. and is considered closest to the current patent application at least to an extent known to the applicant.

US11,391,181B2 described an energy storage system that converts variable renewable electricity to continuous heat at over 1.000 C. Intermittent electrical energy heats a solid medium and the heat from the solid medium is delivered continuously on demand, in this system an array of bricks is used to incorporate internal radiation cavities and they are directly heated by thermal radiation. Thermo-mechanical System for Long-term Energy Storage from the present application is designed to store the generated energy in a form of thermal energy (heat) which then it further transforms into electric energy and hot water as final outputs. In this system instead of bricks as storage material - pre-calculated volume of material with adequate properties (latent heat of fusion, specific heat) that stores the thermal energy produced by the heaters that are connected to the energy source (sun, wind etc.) and whereby recycled glass granulation <=500 mikrons due to lower temperature of melting (latent fusion) is used.

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Accordingly, since the invention has enough stored power to provide one or more homes with electricity and hot water, it can be even shared with neighbors. This makes the invention not only interesting for private homeowners and businesses, but also for energy companies. By stacking several invention storage systems connected to each other, operators or energy suppliers can store and supply energy (and hot water for heating) to entire streets or business parks, which can further smoothen-out the energy peaks and loads to the grid - which are a major problem for energy companies - dunng generation, but also during consumption.

The storage system enclosed in the present patent application can be added to and installed on existing or new energy generation systems and therefore does not disrupt the existing grid and has a low system investment cost: price / KWh ratio.

Actually, this is rechargeable system that is based on the logic of the circular economy and is produced from regular raw materials available worldwide, its expected lifespan in service is 25 years with little-to-no maintenance.

The stored energy can be delivered as electricity and hot water at the same time.

The invention enables utilization of renewable energy sources to their full potential.

The storage system enclosed in the present patent application is effective and innovative product for long-term energy storage management fully in line with zero-carbon policies and without any chemical processed or use of environmentally harmful raw materials, such as zinc, silicon, germanium, manganese, lithium, or cobalt, frequently used in traditional batteries.

The current state of art

Today, renewable energy, mainly generated by solar, wind and hydropower sources, provides more sustainable generated energy alternative as the humanity attempt to decarbonize the society, in the current state of the art, due to limited or non-cost-effective types of storage possibilities available, the problem arises when this energy must be stored, whereby large part of the generated energy ends irreversibly lost.

Description of the invention Brief description of the Figures

Figure 1: Invention system schematics.

Figure 2: The two units of the System: Thermal storage unit and Transformation unit,

Figure 3: Thermal storage unit elements,

Figure 4: Container / housing

Figure 5: Transformation unit mounted, top view, with elements

Figure 6: Water pump

Figure 7: Heat exchanger

Figure 8: Self-designed engine / Tesla Turbine

Figure 9: Power-drop Generator with water droplet explosion transformation in ms.

Figure 10: Steam condenser - schematics

Figure 11 : Radiator

Figure 12: Power generator

Figure 13: Flow control valves

Figure 14: Technical specification of the prototyped invention

Detailed description of the invention

The proposed system as a novel energy storage system is a device that is designed to store the generated energy in a form of thermal energy (heat) which then it further transforms into electric energy and hot water as final outputs. Its schematic overview is given in the Figure 1. It is composed of two main units:

Thermal storage unit and

- Transformation unit - to transform stored energy from heat into electric energy.

These two units as integral parts are shown on figure 2. The thermal storage unit and its elements are shown on figure 3.

The first unit of the thermo-mechanical system is composed of a well-insulated container (cell) fiiled-in with natural, sustainable, fully recyclable energy storage material that has the capacity, by means of change of state (solid-liquid and vice-versa) under temperature change, to absorb great amounts of heat. Due to the high thermal resistance of the containers’ insulation, the thermal losses are brought to minimum and thus the stored thermal energy can be stored for a prolonged amount of time. Electrical energy from various natural, non-continuous sources (sun, wind etc.) is used as an input into the Energy storage system. Suitable model of electric heaters, placed into the container (cell), further transform the generated electric energy (input) into thermal energy. At the next step, by increasing the temperature of the electric heaters when the source of energy is active, the thermal energy from the heaters is being transferred onto the material (for thermal energy storage) placed into the container (cell), which triggers increase of its inner temperature in a form of a sensitive thermal energy up to its melting point temperature, thus the process of energy storage takes place. Once the inner temperature of the energy storage material reaches temperature above the melting point temperature, the material starts to change its state from solid into liquid, which in addition triggers even greater absorption and storage of the thermal energy from the heaters. During this process, the material only slightly increases its inner temperature, and the energy is stored in a form of a latent thermal energy. This process allows to implement the effect of storage of higher amount of thermal energy in a relatively small mass volume of thermal storage material.

The consisting elements of the thermal storage units are - Container (also casing or cell) shown on figure 4 - It is engineered from two parts (body and cover from refractory cement), it houses all the components of the storage unit (internally ) and of the transformation unit (externally, mounted on the outside wall). It is made of steel, reinforced concrete, or any other material or a combination of such, with stabile rigidity properties under high temperature. - isolation - one or more layers of isolation, recyclable and with eco-characteristics, commercially available, with high temperature resistance, to provide minimum heat losses and prolonged storage of the thermal energy.

- Storage material - pre-calculated volume of material with adequate properties (latent heat of fusion, specific heat) will store the thermal energy produced by the heaters that are connected to the energy source (sun, wind etc.). Glass, Silicone, Salt, Basalt, Silicone carbide are few of the materials that can act as a thermal' energy storage materials. For the invention prototype recycled glass granulation <=500 mikrons due to lower temperature of melting (latent fusion) is used.

- High-temperature heaters - with adequate specifications (material SiC) are connected to the energy source and generate heat which is stored as thermal energy.

- Cover - composed of upper plate, rotating butterfly wings and containing the heat exchanger, has the role to control the amount of thermal energy transmitted by the storage material to the heat exchanger.

- Heat exchanger - The pipes of the heat exchanger, connected to the water reservoir and the rest of the transformation unit network, have the rote to absorb the thermal energy in a form of heat from the storage material and transform the water into dry steam that will further run the engine located in the transformation unit.

- Rotating butterfly wings - connected to an angle motor, by rotating for +-90 degrees of an angle, they control the opening/closing of the gap where the heat from the storage material can pass onto the heat exchanger, thus regulating the temperature of the water / steam in the pspes of the heat exchanger. The second unit of the system or the unit for transformation of the thermal stored energy (heat) into electrical energy is shown an Figure 5. Basically, it follows the principle of the Rankine mechanical cycle and is composed of few basic elements:

Reservoir for the working fluid (water)

Fluid pump

- Heat exchanger

- Expander

Condenser for the working fluid

- Cooler and

- Electric generator

The pump sends the working fluid from the reservoir into the heat exchanger, raising at the same time its pressure up to 8 bar, regulated by a safety valve. The heat exchanger, placed directly above the isolated container (ceil) within the cover, and separated by the rotational butterfly plates, has no physical contact with the storage (heated) material whilst the thermal energy (heat) is being transferred - form the material to the working fluid passing through the butterfly plates and taken up by the heat exchanger - by means of thermal radiation. A set of heat-resistant rotating plates play the role of dividers and by opening or reducing the gap space between the container and the heat exchanger, they regulate the amount of transferred heat to the working fluid that is passing thru the exchanger by means of thermal conductivity. When the thermo mechanical system is in discharge mode (the users household have devices switched on) - the Butterfly plates are positioned "open” and the working fluid enters the heat exchanger, it takes over part of the thermal energy by means of convection and increases its inner temperature and its volume. Due to the constant mass flow, typical for the Rankine cycle, a difference in volumes of the working fluid at the entry point and the exit point of the heat exchanger appears. This difference provokes increased speed of movement of the particles of the working fluid at the exit point of the heat exchanger. With such an increased speed, the working fluid then enters the injector placed at the entry point of the expander, getting additional speed. In this context a typical expandor that is generating work is represented by a simple steam engine or a turbine. We use self-designed bladeless turbine with multiple rotational disks for increased efficiency as an expander - work generation element. When the working fluid is moving around the rotational disks of the expander / turbine, due to friction, it transfers part of its kinetic energy to the rotor/rotational disks, and thus, to the rotating axle. As the working fluid transmits its kinetic energy to the rotational disks, it exists the expander/turbine and enters the piping system whereby it is ultimately being taken into the condenser, whereby the excess of the thermal energy Is being released into the coolant. The working fluid retains its temperature of about 70ºC and then enters the reservoir to be stored until a new cycle takes place. The cooling fluid (coolant), after it has received part of the thermal energy from the working fluid In the condenser and its inner temperature has increased, enters the cooler where its temperature is reduced. This small amount of thermal energy is released into the environment.

In order to increase the overall efficiency of the system, the excess thermal energy (heat) that should entirely be released into the environment will actually be channeled, via a separate piping line, into the object (residence unit or industry unit) to be farther used (in case of residence units, for having warm water or heating purposes in wintertime; and in case of industry unit, for technical processes etc.).

The system is also equipped with a by-pass pipe that bypasses the expander/turbine and can channel the working fluid directly into the condenser and thus increases the systems' capacity to produce greater amounts of warm water, if need be. This is enabled by installing two electromagnetic valves that regulate the flow of the working fluid in these lines. This way, the overall parameters of the system can be adjusted to the real situation in-situ, subject to requirements, for a greater warm water production or greater energy storage.

Elements comprising the transformation unit are:

- Water pump shewn on figure 6. Tire aim of the water pump it is to increase the pressure of ths water (in the present application from 1 to 6 bar) securing low mass flow rate (in the present application 0.0036 kg/s) before water is to be injected into the heat exchanger. Due to the low mass flow rate, energy consumption of the water pump is very low. (in the present application the inlet and outlet temperature of the water Is 95°C). Any commercial model with above specifications can be used.

- Heat exchanger shown on figure 7.

This is the high temperature heat exchanger that produces steam when the water coming from the reservoir through the water pump (in the present application with temperature at 95ºC and 6 bar of pressure) is heated up to 350°C. Pressure remains constant all the time, but velocity of the superheated steam is increased up to the point to be injected in the steam turbine.

- Expansion engine shown on figure 8

As an expansion engine, used various types and models of commercially available engines can be used, such as: Steam turbine, Multi-disk turbine, levitating - piston engine, power-drop generator, acoustic engine, vacuum engine etc. The aim of the steam turbine is to convert heat to mechanical energy with high as possible rate, in the system described in the present application, a self-designed multi-disk steam turbine (Tesla turbine) is used. This turbine is using the friction factor of boundary layer on smooth disks in order to produce rotary force of the shaft and in that way to produce energy. - Power-droplet generator shown on figure 9. This is a unique concept of generator which uses the explosion of a droplet of water when Inserted into a heated chamber. If a preheated droplet of water (85ºC) is introduced on a hot plate (300ºC), it will first heat up quickly, but then the droplet will explode, releasing energy. We will use this explosion to set a cylinder in motion. Actually, the principle is the same as in a combustion engine, but now the explosion is not caused by an ignition but by an overheated plate. The system could easily be extended to a rocket engine principle, so that instead of a lunar movement, a rotating movement is made.

- Steam condenser shown on figure 10. The role of the steam condenser is to condense back the working fluid (steam) and in that way to change the phase from gaseous to liquid,

- Radiator shown on figure 11. The role of the Radiator is cooling the coolant of the steam condenser and release of the excess heat in the surrounding. Any commercially available radiator with corresponding technical specifications is suitable.

- Electric power generator shown on figure 12

The Generator will be connected to the steam turbine with a belt (estimated belt reduction rate approximately 1 :6). The Generator will generate electricity for the house or plant. Prototyped with 6KW.

- Flow control valves shown an figure 13. Flow control valves regulate the steam flow, channels the steam to pass thorough the steam turbine or thru the by-pass line. When there is a need to produce electricity, steam is passing through the steam turbine, then to the condenser where it is heating the coolant. Then coolant is directed to the user house heating system or to the battery radiator. When there is a necessity to heat the house heating system, without electricity production, with the help of the flow control valves, steam is being redirected to the by-pass line and therefore the steam is channeled directly to the steam condenser where the coolant is being heated and later transfer that heat to the house heating system.

Technical specifications of the thermomechanical system

The expected lifespan of the thermo-mechanical energy storage system in service is 25 years and is fully recyclable and re-usable. The system is initially capable of storing 2MW of green energy generated by renewable sources (solar, wind etc.) or by simple grid-induced (during off-peak low tariffs) charge with energy to be further utilized when most needed (e.g. during cut-outs, on-peak high tariffs, or industrial grade tariffs).

The system represents a -system in a sturdy steel/concrete casing with dimensions 2,4mx1,9mx2.4m (LxWxH). This makes it possible to place the system underground, so it does not take up any space in or around the home. It shall be connected to:

- Input connection: The source of the energy (solar system, wind turbine(s), biomass plant etc.): - Output connections: The power mains (and the water inlet connections, in case of hot water supply) of the object(s);

Also, it can be operated from an app and synchronized with the rest of the smart home.

The system has low voltage connection and a 230/415 volt connection as standard. The low- voltage connection makes it possible to connect solar panels directly to the system. The system has a low- voltage output and a 230/415-volt output. The system also has hot and cold- water connection which allows hot water supply for home use, heating, even for swimming pools. The system can store a total of 2 Mw/h of energy for more than 5-7 days, placing it into the category of long-term ESS (Energy Storage Systems). The system has projected efficiency of 94%. Maximum power output of the current model is 6 Kw/h (continuous). Future models adjustable to max. 30kW/h within the same size dimensions.

The prototype System - Working Temperature range: Since recycled glass is used as a storage material, it is envisaged that its content is granulated glass coming mainly from bottles, pickle jars and windows, all are made from SLS (soda-iime-sslica) glass. The temperature at which SLS glass changes from exhibiting solid characteristics to exhibiting liquid characteristics is ~580ºC . Thus, the temperatures of the working range is between its softening point and the working point, which for SLS glass is between 580-1000ºC. According to this assumption, the tables bellow will give the information hew long ths thermal energy can be stored in the prototype invention, having used recycled glass as a storage material:

In the winter working regime, on the 11 ^th day, calculating the thermal losses, the temperature of the storage material drops under the minimum temperature of its working regime and would therefore need a recharge. This means that the invented storage system can hold energy for full 10 days, period which is way beyond the current storage systems.