A thermal energy storage system includes one or more containment vessel comprising an internal cavity containing a bed of phase change material (PCM) operable to store thermal energy, an array of heaters embedded in the molten phase change material, and a tube bundle. The heaters are electrically coupled to an electric power source and operable to heat and melt the PCM to a molten state. The tube bundle comprises heat exchanger tubes embedded in the molten PCM and configured to convey a working fluid (e.g., water or other) through a tube-side of the tubes. The tubes may be arranged in plural individual tube cartridge each insertable and removable from the vessel. In operation, the working fluid is heated by absorbing stored thermal energy from the molten phase change material. The PCM may be heated by power extracted from the power grid during off-peak demand periods.

A method for building a temperature prediction model is applicable to a heat cycle system, wherein the method is used to measure a temperature of the heat cycle system to generate a measured temperature data, and compute a response time of the heat cycle system, and the method includes aligning the measured temperature data and a setting value of the heat cycle system to generate a training data according to the response time; and building the temperature prediction model according to a statistic model and the training data.

A method for extracting and storing, respectively, energy in the form of concentration gradients wherein a process of extracting energy comprising the steps of feeding stored gaseous working medium into a working volume (2), compressing the working medium in the working volume (2), spraying a dilute solution into the working volume (2) before or during compression, increasing the temperature of the working medium fed in the working volume (2) by compression, evaporating the dilute solution with the working medium of increased temperature, removing heat from the working medium by the evaporating solution, keeping the heat extracted from the working medium in the form of latent heat of the vapor in the working volume (2), further increasing the temperature of the working medium until the partial pressure of the vapor in it approaches the vapor pressure of a solution of higher concentration at a corresponding temperature, spraying a solution of higher concentration of a vapor pressure of up to 60% of the vapor pressure of the dilute solution into the working medium of an expanding and high solvent vapor content, condensing the vapor in the working volume (2) onto solution droplets of the atomized solution and thereby heating the solution droplets, transferring the heat energy of the heated solution droplets to the working medium through contact surfaces of the solution and the working medium, feeding the heat previously conveyed to the dilute solution vapor during the compression back into the working medium plus as much heat as the condensation heat of the warmer vapor to the solution of higher concentration exceeds the heat of evaporation of the dilute solution, using the heat thus fed for performing work by the expansion of the working medium, obtaining the work performed by the working medium, removing the working medium and the solution from the working volume (2) after the gaseous working medium of low relative humidity is getting into a state near to its initial state, separating the working medium and the solution and returning the working medium to a container (7) for working medium and returning the slightly diluted solution of higher concentration to one of a container (11) for solution of higher concentrations and an additional intermediate container (24). The invention also relates to an apparatus for implementing the method. The invention can be used in all fields, where electric or mechanical energy should be stored for later use, but especially for leveling out the production and consumption differences on electrical power grids.

A method for modifying a solar thermal power plant operating on conventional oil based technology into a hybrid solar thermal power plant includes: providing an oil-based solar thermal power plant, which includes a solar collection system with at least one radiation absorber tube containing a heat transfer oil to be heated by the solar collection system; providing a molten salts solar thermal power plant, which includes a solar collection system to heat a molten salts mixture; and coupling the respective plants such that the hybrid solar thermal power plant is configured to heat medium temperature steam generated by the oil based solar power plant by the molten salts mixture thereby producing high temperature steam and subsequently supplying it to a steam turbine to generate electricity.

A solar power system includes a solar energy collector that has at least one solar receiver that is operable to carry a working fluid and at least one solar reflector that is operable to direct solar energy towards the at least one solar receiver to heat the working fluid. The working fluid has a maximum predefined operational temperature up to which it can be heated. A first storage unit is connected to receive the working fluid from the at least one solar receiver, and a second storage unit is connected to provide the working fluid to the at least one solar receiver. A power block generates electricity using heat from the heated working fluid. A heater is operable to heat the working fluid to approximately the maximum predefined operational temperature.

A method for extracting and storing, respectively, energy in the form of concentration gradients wherein a process of extracting energy comprising the steps of feeding stored gaseous working medium into a working volume (2), compressing the working medium in the working volume (2), spraying a dilute solution into the working volume (2) before or during compression, increasing the temperature of the working medium fed in the working volume (2) by compression, evaporating the dilute solution with the working medium of increased temperature, removing heat from the working medium by the evaporating solution, keeping the heat extracted from the working medium in the form of latent heat of the vapor in the working volume (2), further increasing the temperature of the working medium until the partial pressure of the vapor in it approaches the vapor pressure of a solution of higher concentration at a corresponding temperature, spraying a solution of higher concentration of a vapor pressure of up to 60% of the vapor pressure of the dilute solution into the working medium of an expanding and high solvent vapor content, condensing the vapor in the working volume (2) onto solution droplets of the atomized solution and thereby heating the solution droplets, transferring the heat energy of the heated solution droplets to the working medium through contact surfaces of the solution and the working medium, feeding the heat previously conveyed to the dilute solution vapor during the compression back into the working medium plus as much heat as the condensation heat of the warmer vapor to the solution of higher concentration exceeds the heat of evaporation of the dilute solution, using the heat thus fed for performing work by the expansion of the working medium, obtaining the work performed by the working medium, removing the working medium and the solution from the working volume (2) after the gaseous working medium of low relative humidity is getting into a state near to its initial state, separating the working medium and the solution and returning the working medium to a container (7) for working medium and returning the slightly diluted solution of higher concentration to one of a container (11) for solution of higher concentrations and an additional intermediate container (24).

The invention also relates to an apparatus for implementing the method.

The invention can be used in all fields, where electric or mechanical energy should be stored for later use, but especially for leveling out the production and consumption differences on electrical power grids.

Thermal energy storage systems are disclosed in this application. Systems of the inventive subject matter are designed to reduce maintenance requirements by sequestering, for example, corrosive fluids that might otherwise damage difficult-to-fix internal components are kept out of those components by introducing a non-corrosive heat transfer fluid to facilitate heat transfer between a thermal energy storage medium (e.g., molten sulfur) and a potentially corrosive working fluid. Thus, the potentially corrosive fluid is kept out of a thermal energy storage tank containing the thermal energy storage medium, which, by design, is difficult to repair when internal components corrode or otherwise require maintenance.

Provided is an arrangement for storing heat energy and in particular providing electric energy from heat energy, the arrangement including: a storage for storing heat energy having a charging inlet and a charging outlet; a tank for holding water for a steam generator, in particular heat recovery steam generator, the tank having an inlet and an outlet, a storage-steam-generator pipe between the charging outlet of the storage and the inlet of a heat recover steam generator; a storage-steam-generator valve within the storage-steam-generator pipe, in particular within a first portion of the storage-steam-generator pipe allowing to temporarily open the storage-steam-generator pipe.

Thermal energy storage systems are disclosed in this application. Systems of the inventive subject matter are designed to reduce maintenance requirements by sequestering, for example, corrosive fluids that might otherwise damage difficult-to-fix internal components are kept out of those components by introducing a non-corrosive heat transfer fluid to facilitate heat transfer between a thermal energy storage medium (e.g., molten sulfur) and a potentially corrosive working fluid. Thus, the potentially corrosive fluid is kept out of a thermal energy storage tank containing the thermal energy storage medium, which, by design, is difficult to repair when internal components corrode or otherwise require maintenance.

Thermal energy storage systems are disclosed in this application. Systems of the inventive subject matter are designed to reduce maintenance requirements by sequestering, for example, corrosive fluids that might otherwise damage difficult-to-fix internal components are kept out of those components by introducing a non-corrosive heat transfer fluid to facilitate heat transfer between a thermal energy storage medium (e.g., molten sulfur) and a potentially corrosive working fluid. Thus, the potentially corrosive fluid is kept out of a thermal energy storage tank containing the thermal energy storage medium, which, by design, is difficult to repair when internal components corrode or otherwise require maintenance.