Thermal energy storage systems and methods

Patent metadata

Field	Value
Publication number	US-10267571-B2
Application number	US-201313756098-A
Country	US
Kind code	B2
Filing date	Jan 31, 2013
Priority date	Jan 31, 2012
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

In some embodiments, a thermal energy storage system includes multiple thermal energy storage containers adapted to store thermal energy storage media, the containers having high emissivity inner surfaces that are adapted to radiate heat into the stored thermal energy storage media.

First claim

The invention claimed is:

1. A thermal energy storage system comprising:
multiple thermal energy storage containers each adapted to store thermal energy storage media, the containers having high emissivity inner surfaces that are adapted to radiate heat into the stored thermal energy storage media, wherein the inner surfaces comprise a black layer or coating having an emissivity of approximately 0.5 to 0.99 and high emittance in the infrared wavelength range, the visible wavelength range, or both, wherein the layer or coating comprises one or more of iron sulfide, copper sulfide, molybdenum sulfide, cobalt sulfide, bound carbon, black furnace paint, ferrous oxide, black ceramic, and cobalt oxide;
thermal energy storage media stored within the storage containers, the storage media in each storage container comprising a salt-based phase change material having a melting point of at least 200 degrees Celsius that is substantially transparent to thermal radiation and radiation absorbing material particles suspended within the phase change material that absorb heat radiated by the inner surfaces, wherein the thermal energy storage media has a radiation absorption coefficient of approximately 0.5 to 0.99, wherein the storage containers are filled such that a void space is formed within each storage container that enables the thermal energy storage media within the storage container to expand, the radiation absorbing material particles comprising one or more of cuprous chloride, ferrous chloride, cobalt chloride, cupric oxide, and suspended carbon and having nominal dimensions of 25 nanometers or less, wherein the storage media is tailored so that nearly total absorption of thermal radiation emitted from the inner surfaces is reached in a distance that coincides with a distance between opposing inner surfaces of the containers;
a venting system adapted to control the pressure within the void spaces of the thermal energy storage containers;
multiple heat storage tanks, each thermal energy storage container being provided in a separate storage tank and containing a thermal energy storage media having a different melting point, the heat storage tanks being arranged in a cascade from highest melting point to lowest melting point; and
a circulation system configured to sequentially drive a heat transfer fluid from storage tank to storage tank within the cascade.

2. A method of heating thermal energy storage media, the method comprising:
adding radiation absorbing material particles to thermal energy storage media that includes a salt-based phase change material having a melting point of at least 200 degrees Celsius that is substantially transparent to thermal radiation, the radiation absorbing material particles being adapted to absorb thermal radiation and comprising one or more of cuprous chloride, ferrous chloride, cobalt chloride, cupric oxide, and suspended carbon and having nominal dimensions of 25 nanometers or less, wherein the thermal energy storage media has a radiation absorption coefficient of approximately 0.5 to 0.99;
filling a storage container having high emissivity inner surfaces with the thermal energy storage media such that a void space is formed within the storage container that enables the thermal energy storage media to expand, wherein the high emissivity inner surfaces are adapted to radiate heat into the thermal energy storage media and comprise a black layer or coating having an emissivity of approximately 0.5 to 0.99 and high emittance in the infrared wavelength range, the visible wavelength range, or both, wherein the layer or coating comprises one or more of iron sulfide, copper sulfide, molybdenum sulfide, cobalt sulfide, bound carbon, black furnace paint, ferrous oxide, black ceramic, and cobalt oxide;
providing the storage container within a heat storage tank that contains a heat transfer fluid in which the storage container is immersed;
heating the heat transfer fluid so that the inner surfaces of the storage container radiate heat into a center of the thermal energy storage media;
wherein the thermal energy storage media is tailored so that nearly total absorption of thermal radiation emitted from the storage container inner surfaces is reached in a distance that coincides with a distance between opposing inner surfaces of the storage container.

3. The method of claim 2 , further comprising filling multiple other storage containers with salt-based thermal energy storage media in a manner in which each storage container contains a thermal energy storage medium having a different melting point, providing each storage container in a separate heat storage tank to create a cascade in which the storage tanks are sequentially arranged from highest melting point to lowest melting point, and driving the heat transfer fluid from storage tank to storage tank in the cascade.

Assignees

• Krakow Burton
• Stefanakos Elias K
• Goswami Dharendra Yogi
• Univ South Florida

Inventors

• Krakow Burton
• Stefanakos Elias K
• Goswami Dharendra Yogi

Classifications

• F28D20/026

  with different heat storage materials not coming into direct contact · CPC title

• F28F2245/06

  having particular radiating, reflecting or absorbing features, e.g. for improving heat transfer by radiation · CPC title

• F28F2265/14

  for preventing damage by freezing, e.g. for accommodating volume expansion · CPC title

• F28D20/025 Primary

  the latent heat storage material being in direct contact with a heat-exchange medium or with another heat storage material (F28D20/003 takes precedence) · CPC title

• Y02E60/145

  Cross-Sectional Technologies · mapped topic