Mechanism: Ports As Engineered Discontinuities
A port is a deliberate discontinuity in the structural envelope of a credentialed element. From the structural-engineering perspective, every port is a defect, a local removal of cross-section that, in the absence of design intervention, would act as a stress concentrator and reduce the element's load-bearing capacity. From the electrochemical and operational perspective, ports are necessary: cavity baths require periodic exchange of working fluid, support active fill modes, and must connect to the building's electrical system to deliver energy services. The primitive resolves this tension by treating ports as engineered discontinuities, not incidental ones, each port's geometry and placement is explicitly derived from a structural-admissibility analysis and is recorded in the element's profile alongside the cavity geometry itself.
Ports are placed exclusively at edge faces of the structural element rather than on its primary load-bearing faces. For slab cells, ports exit through the slab edge rather than top or bottom face. For column cells, ports exit through end-block faces above and below the floor-to-floor span. For beam cells, ports exit through end-block faces at the supports. This placement rule reflects the structural reality that edge faces typically experience lower stress under the element's primary load case, and that local stress concentrations at edge-face ports are far more amenable to localized reinforcement (additional rebar, fiber wrap, or thickened wall) than mid-face ports would be.
Operating Parameters: The Four Port Classes
Electrolyte refresh ports admit external pump connection for periodic exchange of cavity electrolyte. The disclosed embodiments use paired inlet and outlet ports at opposite ends of the cavity envelope, sized for refresh cycles measured in tens of minutes for typical cavity volumes. Port diameters fall in the range 12–25 mm for column and beam cells and 25–50 mm for slab cells. The pump connection is on the building exterior or in a service shaft, never on a habitable face.
Active-material refresh ports admit introduction of fresh active-material slurry into the cavity for the active fill mode of operation, in which active material is replaced on a multi-year service interval rather than being permanently sealed at commissioning. Active-material ports are typically larger than electrolyte ports, 50–100 mm, to admit higher-viscosity slurry flow without excessive pump pressure that could stress cavity walls.
Gas-phase access ports admit activator gas introduction for activator-gated chemistries, in which the cell is electrochemically inert until a gas-phase activator is introduced into the cavity headspace. Gas ports are small in diameter, typically 6–12 mm, but require corrosion-resistant materials matched to the activator chemistry, and are equipped with check valves and pressure-relief devices integrated into the port body so that overpressure events do not propagate to the structural envelope.
Electrical terminal ports admit cell connection to the building electrical system. Terminal ports differ from the three matter-exchange port classes in that they carry no fluid and are sealed against ingress by elastomer or cement-mortar grommets. They carry one or more current-collecting bus bars from the cavity electrodes through the structural envelope to an external terminal block. Terminal-port geometry is dominated by electrical clearance and creepage requirements rather than fluid-flow or pressure considerations.
Alternative Embodiments
Several alternative embodiments are contemplated. A first variant combines functions in a single port body, for example, an electrolyte-refresh-and-gas-access combined port that uses a coaxial geometry with electrolyte flow in the outer annulus and gas-phase access through the central bore. A second variant uses redundant ports of each class, so that a single port failure can be isolated without taking the cell out of service; the disclosure recites two-of-three and three-of-five redundancy schemes for safety-critical applications. A third variant integrates instrumentation, temperature, pressure, and reference-electrode probes, into existing port bodies rather than creating dedicated instrumentation ports, reducing the total count of structural discontinuities.
A further embodiment uses recessed ports. Instead of port external interfaces being flush with the edge face, the port terminates inside a recessed pocket cast into the edge face, so that the connection hardware does not protrude from the building envelope and is protected from impact and weather. The recessed-pocket geometry is itself credentialed, with pocket depth and width treated as part of the structural-admissibility analysis.
Composition: Port Body, Liner, And Connection Termination
A port comprises three composed elements. The port body is a corrosion-resistant tube, typically stainless steel, fiber-reinforced polymer, or coated alloy, that traverses the cavity wall from cavity interior to exterior face. The body is cast in place during element fabrication and bonded to the surrounding concrete by mechanical keying features along its length. The port liner, where present, is an inner sleeve of chemically compatible material selected for the specific cavity electrolyte or active material, for example, fluoropolymer for fluorinated electrolytes or nickel for alkaline systems, and is replaceable independently of the port body during maintenance. The connection termination is the external interface that mates with building-side plumbing or electrical hardware.
Connection terminations conform to standard plumbing and electrical interfaces. Fluid-bearing ports terminate in NPT tapered threads for sizes up to approximately 50 mm and in ANSI raised-face flanges for larger sizes, with flange ratings selected to envelop the worst-case operating pressure plus a margin. Electrical terminal ports terminate in IEC electrical terminal classes appropriate to the cell voltage and current ratings, with grounding lugs and creepage spacing per applicable IEC and UL standards. The standard-connection mapping is itself part of the disclosed primitive: the architectural commitment is that an installer with conventional plumbing and electrical training, equipped with conventional tooling, can connect a credentialed structural-electrochemical element to a building's fluid and electrical services without specialized cell-handling equipment.
Prior-Art Posture
Prior art in concrete-embedded systems has typically treated ports as ad hoc penetrations, for example, conduits for embedded post-tension tendons, or sleeves for mechanical-electrical-plumbing service runs, rather than as a classified set of engineered discontinuities tied to the structural-admissibility surface. Prior art in flow-battery systems has standardized fluid connections at the cell module level, but flow-battery cells are external to the structural envelope and their port geometry is not constrained by structural-load considerations. The cavity-port external-interfacing primitive is distinguished by its explicit four-class taxonomy, its edge-face placement rule, its standard-connection mapping that aligns with conventional building trades, and its integration with the credentialed-materials profile so that port placement and geometry are themselves attested artifacts.
Disclosure Scope
Provisional Application 64/050,895 discloses the cavity-port external-interfacing primitive with claim scope spanning the four named port classes, the edge-face placement rule, the standard-connection terminations, and the alternative embodiments above. The primitive is asserted independently of cavity-bath chemistry and aspect-ratio class: any combination of port classes may be deployed in any combination of slab, column, or beam cells with any active-material chemistry. Port geometry parameters (diameter, edge-face placement, wall-thickness margin) are recorded in the element's credentialed profile and are subject to verification at each transition under the profile-versioning-continuity rules, so that subsequent additions, replacements, or retirements of ports are themselves auditable events in the element's lifecycle.
The disclosure further recites operational procedures associated with each port class. Electrolyte refresh follows a flush-and-fill cycle in which the inlet and outlet ports are connected to a service cart that pumps spent electrolyte to a recovery vessel and meters fresh electrolyte into the cavity at a controlled rate, with cavity pressure held below a per-element ceiling that is itself part of the credentialed structural envelope. Active-material refresh is a longer-duration procedure that may require partial drainage of electrolyte through the same ports before the active-material slurry is introduced. Gas-phase activation is a routine commissioning step performed at first energization and is repeated only after long idle periods or maintenance events that exposed the cavity headspace to ambient atmosphere. Electrical terminal connections, once made at commissioning, are normally not disturbed for the service life of the cell, and terminal-port grommets are designed for the longer hold time accordingly.
Finally, the disclosure recites integration of port-state telemetry into the building-management system. Each port body may carry a small instrumentation header that reports port temperature, presence or absence of fluid flow, and integrity of the seal between port body and surrounding concrete. Telemetry signals are not load-bearing for the structural-admissibility analysis but are useful for early detection of port-level anomalies, a slowly weeping electrolyte port, a stuck check valve on a gas port, a loosening terminal lug, long before such anomalies propagate into structural or electrochemical failure modes. Port telemetry forms part of the element's operational record and is fed back into the profile-versioning chain as periodic state attestations rather than as transitions, so that the chain itself remains compact while observable port behavior is retained for forensic use.
