Provided is a heat storage tank including at least one chemically inert solid heat storage material containing at least calcium carbonate particles, in which the calcium carbonate particles have a size distribution with a diameter d50 of from 0.5 mm to 200 mm.

Energy storage systems include a heat source and a thermal energy storage system to store thermal energy produced by the heat source. The thermal energy storage system includes a first tank containing a first salt having a first melting temperature and a second tank containing a second salt having a second melting temperature. At least one input conduit is configured for transferring thermal energy from the heat source to the first tank and second tank. A first output conduit is in thermal communication with the first tank. A second output conduit is in thermal communication with the second tank. Additional energy storage systems include a heat booster positioned and configured to add thermal energy to a heated heat transfer fluid prior to reaching a tank containing at least one thermal storage material. Methods include transferring thermal energy from a thermal energy source to a plurality of thermal energy storage tanks.

A method of pumping a heat transfer fluid in a thermal energy storage system comprising a first thermal energy storage tank connected to a second thermal energy storage tank via a bi-directional flow member. The first and second thermal energy storage tanks are associated with a pressure vessel system comprising a first and second pressure vessel each pressure vessel being partially fillable with an actuating liquid, wherein, the method for pumping comprises: displacing the actuating liquid from the first pressure vessel to the second pressure vessel, thereby creating a pressure difference in the first thermal energy storage tank with respect to the second thermal energy storage tank, and therein displacing the heat transfer fluid via the bi-directional flow member.

The invention proposes a method and a device (10) for thermal-electrochemical energy storage and energy provision. The device (110) comprises: at least one thermal energy store (118), wherein the thermal energy store (118) comprises at least one heat transport medium (121) and at least one storage medium (119) selected from the group consisting of an electromagnetic storage medium, a thermal storage medium; at least one heating device (134), wherein the heating device (134) is designed to receive the heat transport medium (121) from the thermal energy store (118), to heat this medium and return it to the thermal energy store (118); at least one electrochemical cell (146), wherein the electrochemical cell (146) comprises at least one gas chamber (148), wherein the electrochemical cell (146) further comprises at least one first electrode (150) and at least one second electrode (152): wherein the second electrode (152) is designed as a 3-phase electrode (154), wherein the 3-phase electrode (154) has at least one first phase boundary (156) to the gas chamber (148) and at least one second phase boundary (158) to the electrochemical storage medium (119); wherein the electrochemical cell (146) is designed to electrochemically react the electrochemical storage medium (119); and at east one container (160), wherein the container (160) is designed to receive a supply on the heat transport medium (119), wherein the container (160) is further designed to receive the thermal storage medium (119) from the thermal energy store (118).

The production of NH.sub.3, Urea, UAN, and DAP, starting from inherently intermittent renewable energy, such as photovoltaic and wind power, is made economical by use of molten salt thermal energy storage (ESS) and water electrolyzer (WE) concentrated oxygen. The process inputs and equipment apply air; hydrogen-containing fuel, such as biomass; WE (concentrated O.sub.2 and H.sub.2 producing); thermal ESS equipped with a turbine and generator to steady the electricity input to the WE; and an ammonia plant. The thermal ESS enables minimally sized process equipment including, the WE, the air separation unit and less hydrogen storage. The concentrated oxygen from the water electrolyzer uniquely enables high-temperature thermal ESS input, water and CO2 collection and other fertilizer products, including Urea, UAN and DAP. DAP production is facilitated by using WE high-purity O.sub.2 oxidation and ammonium nitrate is similarly facilitated by anhydrous NH.sub.3 oxidation.

The invention relates to an improved Brayton concentrated solar power generation method, which belongs to the technical field of solar power generation. The method performs the following steps under normal pressure or micro positive pressure: (1) the heat storage medium enters the heat collection device from the low-temperature tank; (2) the sunlight is collected to the heat collection device to transform the heat storage medium into the high-temperature heat storage medium; (3) the high-temperature heat storage medium enters the heat exchanger and exchanges heat with the power working medium; (4) the high-temperature power working medium after heat exchange enters the turbine generator set to provide power generation. Based on the method, the invention also provides a matched power generation system. Adopting the method and device of the invention for power generation has the advantages of low cost, easy construction and maintenance, high efficiency, less restriction, etc., can realize long-term and stable power generation, can be applied to any area, and is conducive to large-scale promotion.

The present disclosure relates to techniques for extracting heat energy from geothermal briny fluid. A briny fluid can be extracted from a geothermal production well and delivered to a heat exchanger. The heat exchanger can receive the briny fluid and transfer heat energy from the briny fluid to a molten salt. The molten salt can be pumped to a molten salt storage tank that can serve as energy storage. The briny fluid can be returned to a geothermal source via the production well. The briny fluid can remain in a closed-loop system, apart from the molten salt, from extraction through return to the geothermal production well.

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.

Various embodiments of the disclosure provide reference electrodes for use in electrochemical systems (e.g., electrochemical cells) that use molten salt media as the electrolyte of choice. The reference electrodes include a metal core with an outer, solid layer of the metal's oxide, silicide, or carbide. The oxide, silicide, or carbide outer layer may be formed uniformly and with sufficient durability to withstand exposure to molten salt material. The outer layer may be formed by processes configured to form (e.g., grow) the oxide, silicide, or carbide layer directly on the outer surface of the metal core with uniformity of the layer's composition and thickness all along the outer surface of the metal core. Related electrochemical systems are also disclosed.

Methods and systems for energy storage and management are provided. In various embodiments, heat pumps, heat engines and pumped heat energy storage systems and methods of operating the same are provided. In some embodiments, methods include controlling thermal properties of a working fluid by virtue of the timing of the operation of cylinder valves. Methods and systems for controlling mass flow rates and charging and discharging power independent of working fluid temperature and system state-of-charge are also provided.