NASA’s Kennedy Space Center (KSC) has created the Cryo-Fluid Capacitor (CFC) that capitalizes on the energy storage capacity of liquefied gases, and the relative simplicity of high-pressure gas bottles while limiting the downfalls associated with both methods. By exploiting a unique attribute of nanoporous materials — aerogel, in this case — fluid commodities such as oxygen, hydrogen, methane, etc. can be stored in a molecular surface adsorbed state at densities on par with liquid, at low to moderate pressure, and then supplied as a gas, on-demand, to a point of interest.
High-pressure gas must be stored in vessels with heavy, thick walls, and cryogenic liquids require complex storage systems to limit boil-off and are not well suited for overly dynamic situations where the tank orientation can change suddenly (e.g. in an airplane or car). The CFC addresses these issues, while still providing excellent energy storage capability.
Storage and transfer of fluid commodities such as oxygen, hydrogen, natural gas, nitrogen, argon, etc. is an absolute necessity in virtually every industry. These fluids are typically contained in one of two ways: as low-pressure, cryogenic liquids, or as high-pressure gases. Energy storage is not useful unless the energy can be practically obtained (un-stored) as needed. In the present case, the goal is to store as many fluid molecules as possible in the smallest, lightest-weight volume possible, and to supply (un-store) those molecules on-demand as needed in the end-use application. The CFC concept addresses this dual storage/usage problem with an elegant charging/discharging design approach.
The CFC technology includes ingenious packaging in its design. Tightly coiling aerogel blanket into a cylinder allows for a larger amount of the storage media (aerogel) to be densely packaged into a manageable geometry. A spirally integrated conductive membrane also acts as a large-area heat exchanger that easily distributes heat through the entire cylinder to discharge the CFC quickly, and can be interfaced to a cooling source to charge it up. This feature also allows the cryogenic fluid to easily penetrate the cylinder for fast charging. Another important note is that the unit can be charged up with cryogenic liquid or from an ambient temperature gas supply, depending on the desired manner of refrigeration. Another novel feature is the heater integration. Two promising methods have been fabricated and tested that evenly distribute heat throughout the entire core, both axially and radially.