Category: [TECHNOLOGY]
Type: [Starship Component, Thermal Storage System]
The Molten-Salt Heat Battery (MSHB) is a high-capacity thermal energy storage system utilized aboard FTL-capable Terran Sphere starships. Its primary function is to absorb the massive, sudden influx of waste heat generated during the operation and collapse of a [CID FTL Drive] warp bubble. Composed of a phase-change salt-graphite composite typically housed in robust keel-mounted cartridges, the MSHB temporarily stores this energy, allowing it to be dissipated gradually by the ship’s main [Thermal Control Suite (Starship)] over several hours.
| Parameter/Symbol | Meaning/Description | Value / Specification |
|---|---|---|
| System Type | Latent heat thermal energy storage system (Thermal Battery) | - |
| Storage Medium | Phase-change salt eutectic (e.g., NaF-NaOH-NaCl) mixed with graphite composite | Optimized for high latent heat & thermal conductivity |
| $L_h$ | Specific latent heat of fusion of the storage medium | $1.0 \, \text{MJ kg}^{-1}$ ($1 \times 10^6 \, \text{J kg}^{-1}$) |
| $Q$ | Total heat energy to be stored (typically $Q_{\text{FTL}}$ from an FTL jump) | Varies with jump energy (e.g., $\approx 1.5 \times 10^{14} \, \text{J}$ for courier) |
| $m_{\text{batt}}$ | Required mass of the MSHB storage medium | $m_{\text{batt}} = Q / L_h$ (e.g., $\approx 150 \, \text{tonnes}$ for courier) |
| Configuration | Typically modular cartridges, often located in the ship’s keel or other structurally sound, thermally isolated areas | - |
| Emergency Jettison | Capability to jettison overheated or damaged cartridges | Standard safety feature |
Relevant Equations:
The operation of a [CID FTL Drive] is an energetically violent process. While only a tiny fraction ($\varepsilon \approx 0.05\%$) of the total jump energy manifests as waste heat, this still amounts to hundreds of petajoules for a typical starship jump. Radiating such an immense thermal load instantaneously is far beyond the capacity of any practical shipboard radiator system. The Molten-Salt Heat Battery (MSHB) provides the crucial “thermal buffer” to absorb this energy spike.
Operating Principle & Composition: The MSHB functions as a phase-change thermal capacitor. It utilizes a carefully selected eutectic mixture of salts (e.g., Sodium Fluoride, Sodium Hydroxide, Sodium Chloride - NaF-NaOH-NaCl) as its primary phase-change material (PCM). These salts are chosen for their high specific latent heat of fusion ($L_h$), meaning they can absorb a large amount of energy as they transition from solid to liquid (melt) at a relatively constant temperature. To enhance thermal conductivity and structural integrity, the salt mixture is typically infused into a porous graphite composite matrix. Graphite’s high thermal conductivity ensures that heat from the ship’s coolant loops (which collect waste heat from FTL systems) can be rapidly and efficiently distributed throughout the salt medium, promoting uniform melting.
When a ship performs an FTL jump, the waste heat ($Q_{\text{FTL}}$) is channeled via the [Thermal Control Suite (Starship)] into the MSHB. The salts within the battery melt, absorbing the energy as latent heat. The MSHB is sized such that its entire PCM mass can melt without its overall temperature rising to a point that would damage the battery or surrounding ship structures. For a standard 700-tonne courier, an MSHB with approximately $150 \, \text{tonnes}$ of PCM is required to absorb the $\approx 1.5 \times 10^{14} \, \text{J}$ of heat from a typical 6-light-year jump. Once the FTL jump is complete and the heat is stored, the MSHB then acts as a heat source. The ship’s TCS circulates coolant through the (now molten) battery, gradually drawing out the stored thermal energy and transporting it to the ship’s main radiator panels for dissipation into space over several hours. The salts within the MSHB slowly re-solidify as they release their stored heat.
Physical Configuration & “Used Future” Feel: MSHBs are substantial components, often comprising a significant fraction of a starship’s non-payload mass. They are typically configured as a series of robust, heavily insulated cartridges or tanks, often located deep within the ship’s structure, such as along the keel, to provide a central, structurally sound mounting point and some degree of protection. These cartridges are designed to be replaceable, though doing so is a major starport maintenance task. Externally, an MSHB module might appear as a series of large, featureless, heavily insulated cylinders or blocks, with prominent inlet/outlet ports for high-temperature coolant lines. Warning placards indicating extreme temperatures and high thermal energy storage would be clearly visible. In an older ship, the insulation blankets might be scuffed, patched, or stained from minor coolant weeps over years of service. The support framework holding the cartridges might show signs of thermal stress cycling. An emergency jettison system allows dangerously overheated or damaged cartridges to be ejected into space, a last-ditch safety measure that would leave the ship unable to perform further FTL jumps until the battery is replaced.
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