| CPC F28D 20/025 (2013.01) [F28D 2020/0082 (2013.01)] | 11 Claims |
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1. A method of operating a thermal energy storage, TES, system, wherein the TES system comprises,
a thermodynamic gas flow circuit containing a working fluid that is not in liquid phase but maintained in gas phase throughout the gas flow circuit;
a first TES container containing a first TES medium as a hot storage medium, wherein the first TES medium is in thermal connection with the gas flow circuit along a first gas flow path for exchange of thermal energy with the gaseous working fluid, wherein the first gas flow path is part of the gas flow circuit;
a second TES container containing a second TES medium as a sensible cold storage medium for storing thermal energy and a second gas flow path through the second TES medium for exchange of thermal energy between the gaseous working fluid and the second TES medium, wherein the second gas flow path is part of the gas flow circuit;
an energy converter for converting between electrical energy and thermal energy of the gaseous working fluid in the gas flow circuit; the energy converter comprising an electrical motor, an electrical generator, and a compressor/expander system, the compressor/expander system comprising a compressor and an expander, wherein the compressor is functionally connected to the motor for being driven by the motor during a charging period, and the expander is functionally connected to the generator for driving the generator during a discharging period;
wherein the method comprises during a charging period,
driving the compressor by the motor and adiabatically compressing the gaseous working fluid by the compressor, and circulating the gaseous working fluid through the gas flow circuit from the compressor through the first gas flow path, then through the expander, and then through the second gas flow path, and back to the compressor;
wherein the TES system comprises a latent TES system, the latent TES system comprising a latent TES container that contains a latent TES medium,
wherein a latent gas flow path extends through the latent TES container for exchange of thermal energy between the gaseous working fluid and the latent TES medium during the flow of the gaseous working fluid through the latent TES container along the latent gas flow path, wherein the latent gas flow path is part of the gas flow circuit and located between the compressor/expander system and the second TES container with respect to flow of the gaseous working fluid;
wherein the latent TES container comprises a spray nozzle arranged for spraying the latent TES medium as atomized liquid droplets into the latent gas flow path;
wherein the method comprises spraying the latent TES medium as atomized liquid droplets into the latent gas flow path during the charging period and heating the gaseous working fluid by transferring thermal energy from the atomized droplets to the gaseous working fluid and cooling the droplets into ice particles so as to provide a snow of the latent TES medium in the latent TES container.
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