Salt-Hydrate PCM
Glauber's Salt / Calcium Chloride Hexahydrate PCM
Salt-hydrate phase change materials, primarily Glauber’s salt and calcium chloride hexahydrate encapsulated in stainless steel, store thermal energy by melting at 30 to 32 °C with a latent heat of 220 kJ/kg. The Moon's 300 K temperature swings and 14-day lunar nights demand dense thermal storage to maintain stable temperatures without electrical power. With a density of 1,500 kg/m³, these inorganic hydrates offer higher volumetric thermal capacity than paraffin, while closed-cell encapsulation prevents chemical phase segregation across repeated freeze-thaw cycles over a 30-year operational lifetime.
Inorganic salt-hydrate PCMs (Glauber's salt, CaCl2.6H2O) for higher-density thermal storage at specific temperatures.
Purpose
Inorganic salt-hydrate PCMs (Glauber's salt, CaCl2.6H2O) for higher-density thermal storage at specific temperatures.
Context
Child of L2-PTC-PCM within the Lunar Ark system
Principles
- ▸Glauber's salt (Na2SO4.10H2O) melts at 32 C, latent ~250 kJ/kg
- ▸CaCl2.6H2O melts at 30 C, latent ~190 kJ/kg
- ▸Higher density than paraffin
- ▸Closed-cell encapsulation prevents segregation
- ▸Compatible with engineered lunar regolith composites
Typical implementations
- ▸NASA building thermal mass studies
- ▸Industrial CSP salt-hydrate storage
- ▸Engineered Lunar Composite PCM (ScienceDirect 2025)
Lunar considerations
- ▸Higher density saves mass for given thermal capacity
- ▸Long-life encapsulation prevents segregation
- ▸ISRU-producible from lunar Ca/S
Specifications
Functional
| primary function | Inorganic salt-hydrate PCMs (Glauber's salt, CaCl2.6H2O) for higher-density thermal storage at specific temperatures. |
| latent heat kj per kg | 220 |
| melting c | 32 |
| density kg per m3 | 1500 |
Physical
| mass kg | 15 |
| materials | Glauber's salt, CaCl2 hydrate, Stainless encapsulation |
| vacuum compatibility | True |
Operational
| power consumption w | 0 |
| thermal range c | -40, 70 |
| lifetime years | 30 |
| mtbf hours | 1000000 |
Interfaces
Provides
- Higher-density thermal buffering
Requires
- PCM fill
Cite this entry
Lunar Ark Codex. "Salt-Hydrate PCM" (L3-PTC-PCM-SALT). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-PTC-PCM-SALT
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.