A plant for storing and discharging thermal energy comprises a first heat exchanger coupled to a heat source, a second heat exchanger coupled to a heat user, a fluid configured to store thermal energy, a storage device for the fluid, a circuit configured to couple the first heat exchanger, the second heat exchanger and the storage device. The storage device comprises N+B storage sections fluidly connected to each other, where N is equal to or greater than two and B is less than N; each of the N+B storage sections has a same containment volume. The fluid occupies a volume substantially equal to N times the containment volume. A separation gas is inserted in the storage device, is in contact with the fluid and is configured to always keep separate a hot portion of the fluid from a cold portion of the same fluid.

In one aspect, thermal energy storage compositions are described herein. In some embodiments, a composition comprises 0.5-10 wt. % polysaccharide and 88-99.5 wt. % water, wherein the weight percentages are based on the total weight of the composition. Moreover, in some cases, the composition is shape stable at 20° C. and 1 atm.

A thermal energy storage system comprising a working fluid to store and transfer thermal energy between a heat source and a thermal load and a vessel to store the working fluid. The vessel has an interior region and a floating separator piston in the interior region to separate a hot portion from a cold portion of the working fluid. There is a first manifold thermally coupled to an output of the heat source and to an input of the thermal load and fluidly coupled to the interior region of the vessel and a second manifold thermally coupled to an input of the heat source and an output of the thermal load and fluidly coupled to the interior region of the vessel. There is a controller configured to maintain the working fluid in a liquid state.

Systems and methods relating to use of external air for inventory control of a closed thermodynamic cycle system or energy storage system, such as a reversible Brayton cycle system, are disclosed. A method may involve, in a closed cycle system operating in a power generation mode, circulating a working fluid may through a closed cycle fluid path. The closed cycle fluid path may include a high pressure leg and a low pressure leg. The method may further involve in response to a demand for increased power generation, compressing and dehumidifying environmental air. And the method may involve injecting the compressed and dehumidified environmental air into the low pressure leg.

A heat accumulating unit includes an upstream heat accumulator and a downstream heat accumulator each accommodating a supercooling heat accumulating material. Each of the upstream heat accumulator and the downstream heat accumulator has a channel in which fluid flows. In heat accumulation of the supercooling heat accumulating material, the channel of the upstream heat accumulator and the channel of the downstream heat accumulator are set in a serial connection state by a serial connection pipe. In a temperature rise mode, fluid that has passed through the channel of the upstream heat accumulator flows in a bypass pipe.

A system including: (i) a pumped-heat energy storage system (“PHES system”), wherein the PHES system is operable in a charge mode to convert electricity into stored thermal energy in a hot thermal storage (“HTS”) medium; (ii) an electric heater in thermal contact with the hot HTS medium, wherein the electric heater is operable to heat the hot HTS medium above a temperature achievable by transferring heat from a working fluid to a warm HTS medium in a thermodynamic cycle.

The invention provides shape-stable products for storing and releasing thermal energy, based on thermoplastic polymer compositions containing organic phase change materials (PCM) incorporated into a polymer matrix, the products withstanding multiple melting-crystallization cycles of the PCM while maintaining their shape, dimensions, and the thermal energy storage capacity.

The invention relates to a method for operating a sorption system (1), the sorption system comprising the following: a cooling fluid circuit (8), which has a cooling fluid; a process medium circuit (6), which has a refrigerant and a solvent; an absorber (3), which is connected to the cooling fluid circuit (8) and to the process medium circuit (6); a condenser (5), which is connected to the cooling fluid circuit (8) and to the process medium circuit (6); and a control device. During operation of the sorption system (1), the cooling fluid is fed to the absorber (3) and to the condenser (5), and a feed of the cooling fluid to the absorber (3) and a feed of the cooling fluid to the condenser (5) are controlled differently from each other by means of the control device. The invention further relates to an arrangement for a sorption system (1) and to a sorpotion system (1).

The present invention provides a phase change cold storage device having vortex coiled tubes, which falls within the technical field of low temperatures and comprises an inlet tube, an outlet tube, a tube plate, a baffle plate, vortex coiled tubes, a cylinder body, a central tube, a support frame, a seal head and a saddle, wherein the tube plate is fixedly connected to the cylinder body, a lower end position and a central position of the tube plate are respectively perforated, the inlet tube and the outlet tube are respectively connected to a lower end position and a central position of the tube plate, the baffle plate and the vortex coiled tubes are mounted on the central tube, one end of the central tube is fixed on the tube plate, and the other end is inserted through the support frame connected to the cylinder body, the head is connected to the cylinder, provided on the opposite side of the inlet and outlet tubes, and the saddle is provided below the cylinder. The present invention has a compact structure, is easy to manufacture, and easily enhances heat transfer with vortex coiled tubes, and at the same time, has a good cold storage effect and a wide application range.

The present invention is related to a method for obtaining nitrate-based eutectic mixtures based on a BET model to thermal storage of solar refrigeration systems within the range of temperature from 0 to 15° C. Mixtures based on the following hydrate salts: LiNO.sub.3—NaNO.sub.3—Mn(NO.sub.3).sub.2—H.sub.2O, LiNO.sub.3—NH.sub.4NO.sub.3—Mn(NO.sub.3).sub.2—H.sub.2O, LiNO.sub.3—Mn(NO.sub.3).sub.2—Mg(NO.sub.3).sub.2—H.sub.2O, LiNO.sub.3—NH.sub.4NO.sub.3—Mg(NO.sub.3).sub.2—H.sub.2O and LiNO.sub.3—Mn(NO.sub.3).sub.2—Ca(NO.sub.3).sub.2—H.sub.2O, having melting points of 10.8, −1.1, 13.1, 12.0 and 7.1° C., respectively. Thermal and physical properties were established such as the heat of crystallization/melting, calorific capacity to solid and liquid phases, viscosity, density and change of volume during the mixture of eutectic mixtures. The results of energy storing density (esd) varied from 238.3 to 304.5 MJ.Math.m.sup.−3. The phase changing material (PCM) being more potent to be used in solar energy-assisted air conditioning systems (AC) is LiNO.sub.3—NaNO.sub.3—Mn(NO.sub.3).sub.2—H.sub.2O.