Variable Conductance Heat Pipes (VCHPs)
ACT (Advanced Cooling Technologies)
Passive spacecraft thermal control devices combining two-phase working fluid with a Non-Condensable Gas reservoir to automatically regulate evaporator temperature across wide power and sink condition ranges.
Technical specifications
- Effective Thermal Conductivity
- 10,000 to 100,000 W/m·K
- Control Method
- Passive (Non-Condensable Gas)
- Moving Parts
- None
- Material Systems Available
- Aluminum-ammonia; Copper-monel/water; Sodium-Haynes
- Quality Certification
- ISO 9001:2015, AS9100D
About
Variable Conductance Heat Pipes (VCHPs) extend standard heat pipe technology by incorporating a Non-Condensable Gas (NCG) reservoir, enabling the device to passively regulate evaporator temperature without any active control systems or moving parts. As power or sink conditions change, the NCG expands or contracts within the condenser section, blocking or opening varying lengths of condenser area.
At high power levels, elevated vapor pressure drives the NCG into its reservoir, opening the complete condenser for maximum heat transfer. As power decreases, vapor pressure drops, allowing the NCG to expand and partially block the condenser. Thermal conductivities span 10,000 to 100,000 W/m·K.
ACT manufactures VCHPs in multiple material-fluid combinations: aluminum-ammonia for standard spacecraft temperatures, copper-monel/water for microgravity systems, and sodium-Haynes for high-temperature applications. ACT has delivered flight hardware for NASA planetary lander programs including Peregrine and VIPER.
Documentation
Need the full ICD, test reports or a specific revision? Ask the supplier directly.
