The invention provides, in some aspects, a thermal energy storage and retrieval system with a cavity containing a working fluid and a heat transfer surface disposed in the cavity transverse to a gravity field and in thermal coupling with an ice that is formed from and floating in the working fluid. The heat transfer surface transfers to that ice heat from a heat transfer medium that is thermally coupled to the heat transfer surface. According to aspects of the invention in which the ice is less dense than the working fluid, the heat transfer surface is disposed above (with respect to the gravity field) a region of the cavity where that ice is formed or inlet. According to aspects of the invention in which the ice is more dense than the working fluid, the heat transfer surface is disposed below that region.

An energy transportation and grid support system utilizes at least one transportable containment module capable of storing thermal or chemical energy typically produced from renewable or geothermal sources and providing connectivity with energy conversion equipment typically located in a land or sea-based operating facility. The system includes circuitry to hookup to an adjacent electricity grid for the provision of grid support and/or piping to move thermal energy typically used to drive steam turbines generating electricity. The operating facility also includes a communication arrangement to link with and exchange operations control data with a grid or heating operator and the energy transportation operator. The invention is directed to both apparatus and method for the energy transportation and grid support system.

There is herein described phase change materials (PCMs) comprising at least one or a plurality (e.g. a mixture) of tetrafluoroborate salts that are capable of undergoing a solid to solid phase transition. In particular, there is described phase change materials (PCMs) comprising at least one or a plurality (e.g. a mixture) of tetrafluoroborate salts where there is at least one tetrafluoroborate salt or a plurality of tetrafluoroborate salt which have a solid to solid phase transition. The tetrafluoroborate salt may comprise at least one anion or a plurality of the same or different anions of tetrafluoroborate (e.g. BF.sub.4—). The PCM may have a solid to solid phase change in the region of about −270° C. to about 3,000° C., about −50° C. to about 1,500° C., about 0° C. to about 1,000° C., or about 0° C. to about 500° C. temperature range.

A device to store energy includes a phase change material (PCM), with a phase change temperature Tc, contained in a sealed container and constituting a storage core. A source to exchange heat with the PCM, at a temperature TA, to cause a phase change of the PCM. A recuperator to exchange heat with the PCM, at a temperature TB, to cause a phase change of the PCM in the opposite direction to the phase change produced by the source. A controller to control the heat flows between the PCM, the source and the recuperator. An apertured support in contact with the PCM in the sealed container and in thermal contact with the source and the recuperator.

A transportable PCM (phase change material) module comprises a number of PCM packs; a housing for thermally insulting said number of PCM packs from a module's surrounding medium; spaces separating said packs and forming one or more channels for the flow of a fluid; said housing incorporating a fluid inlet and a fluid outlet; whereby, in use, fluid flows through said channels from said inlet to said outlet. A PCM (phase change material) pack comprises a laminate of a first conducting panel and a second conducting panel enclosing a portion formed primarily of PCM; wherein said portion of PCM incorporates thermal conductors.

A metal heat storage apparatus comprises a metal heat storage medium, a medium insertion chamber insulating the inner side, outer side and the floor of the metal heat storage medium; an outer wall structure made of concrete further insulating the metal heat storage medium and including a floor, a central column, an outer wall body, and an upper cover; an infrared ray reflecting mirror disposed below the upper cover constituting the outer wall structure and reflecting infrared rays generated from the metal heat storage medium; a heat exchanger spirally disposed inside the metal heat storage medium and including supply and drain tubes exposed to the outside of the outer wall structure; a solar heater buried in the metal heat storage medium; and a high-density optical input port passing through the outer wall body and the insulating outer wall to provide solar energy to the solar heater.

Fuel-cell thermal management systems and control schemes therefore are disclosed. In one embodiment, the system may include a fuel-cell stack, a heat-exchanger, a thermal battery including a material having a melting temperature of 50-120° C., a first coolant loop including the fuel-cell stack and the thermal battery and excluding the heat-exchanger, and a second coolant loop including the fuel-cell stack, the thermal battery, and the heat-exchanger. The first and second coolant loops may be configured to heat and cool the fuel-cell stack, respectively. The system may include a controller or processor configured to direct coolant to transfer heat from the thermal battery to the fuel-cell stack based on a negative heat rejection status of the fuel-cell stack and to transfer heat from the fuel-cell stack to the thermal battery based on a positive heat rejection status of the fuel-cell stack when the thermal battery is below a target temperature.

Energy storage systems are disclosed. The systems may store energy as heat in a high temperature liquid, and the heat may be converted to electricity by absorbing radiation emitted from the high temperature liquid via one or more photovoltaic devices when the high temperature liquid is transported through an array of conduits. Some aspects described herein relate to reducing deposition of sublimated material from the conduits onto the photovoltaic devices.

Methods and apparatus are disclosed for high-efficiency thermal storage with a fluid-filled “battery” tank positioned within a fluid-filled “reservoir” tank. Fluid loops couple the tanks to a heat pump and a building. The heat pump can charge the battery tank or deliver thermal energy (cold or heat) to a building, using the reservoir tank or ambient air as a thermal energy source. The battery tank can discharge energy to the building jointly with the heat pump or, at periods of peak electricity usage, with the heat pump switched off. Operating modes allow significant savings in electricity usage and mitigate the “duck curve.” Low duty cycle usage of the reservoir enables efficient underground thermal storage with less digging than conventional geothermal technologies. Additional efficiency is achieved with phase change materials installed inside a tank or in a tank wall, providing temperature regulation. Control methods are disclosed.

A module for thermal storage by a phase-change material includes a vat, at least one heat-exchanger having first and second connecting ends configured to be connected to a heat-transfer fluid network, the first and second connecting ends penetrating and opening into the vat, and a structure received in the vat and configured to contain a phase-change material. The structure includes a porous matrix made of a metallic material with communicating cells crossed by the heat-exchanger and in contact with the external surface of the heat-exchanger. The matrix is obtained by moulding around the heat-exchanger. The vat includes at least one wall made of a metallic material formed directly during moulding and integral with the matrix.