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Mike Kowalkowski Week 2: January 25 th , 2007. Project Aquarius Power Engineering Habitat, Battery, and Rover Power Sizing. HAB Power System. Conceptual Design Sustainable uninterrupted power supply for human use Assumptions & Trades 2x human factors req. Control systems & communications
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Mike KowalkowskiWeek 2: January 25th, 2007 Project Aquarius Power EngineeringHabitat, Battery, and Rover Power Sizing
HAB Power System • Conceptual Design • Sustainable uninterrupted power supply for human use • Assumptions & Trades • 2x human factors req. • Control systems & communications • Safety Factor 1.5 • 25% budget for peak loads • P / M / V – 2 HAB Stations • Power: 100 kWe capacity • IMLEO Mass: 4650 kg • Volume: 57.5 m^3 • Reactor and fuel cell fuel not included in mass / volume ISPP H2 &O2 Ga-As Solar Cells 10 20 REG
Satellite Batteries: Power: 2 kWe Solar Battery Li-Ion Rechargeable (2hr) IMLEO Mass: 102 kg Volume: 7.3 m^3 Scalable power density Includes solar paneling Unmanned System Battery: Power: 0.1~0.5 kWe Battery NaS Rechargeable (5 day) IMLEO Mass: 106 ~ 530 kg Volume: 0.07 ~ 0.35 m^3 No theoretical long term storage loss Assume nominal solar chg. Mars Rover (Manned): Power: 15kWe & PMAD Regenerative Fuel Cell 12 hour fuel budget Li-Ion Rechargeable (1hr) IMLEO Mass: 265 kg Volume: 2.0 m^3 Fuel weights neglected, but ~100 kg in situ fuel needed Based on utilization of efficient cryogenic storage (10% dry mass budget) Battery System Style & Sizing
Backup Slides Week 2 Readiness Level
Power budget 20 kWe to sustain life support systems (Courtesy: Kate Mitchell) 20 kWe to sustain control systems, communications, and peaking demands 25% total margin PMAD losses 8.3% power budget (Courtesy: Larson & Pranke) Resistance losses 2% power budget (Courtesy: Larson & Pranke) Unexpected demand 14.7% power budget HAB Power Budget
Primary System PMAD & Nuclear PMAD mass ~ 11.1 kg/kWe 1 Also require wiring budget ~ 0.5 mt / HAB Battery bank regulation system 1 Li-ion rechargeable batteries 150 Wh / kg specific energy Battery 88% efficient Density 260 Wh/L 0.168% discharge/month NaS batteries 132 Wh/kg specific energy Battery 86% efficient Density 160 Wh/L 0% discharge/ month Secondary System Direct fuel cell system 1.4 kWe/kg dry mass 2 1.5 We/cm^3 density 2 Fuel / oxidizer containment tanks 3 Baseline 200 kg fuel / day / 50 kWe 1 Solar cells 1 GaAs system specific mass 2.05 kg/m^2 Solar flux is 593 W/m^2 4 Efficiency of solar panels 18.5% Efficiency of array ~ 75% from table 2-6 1 HAB M / V Calculations
Calculations • Calc. Theory from Human Spaceflight: Mission Analysis and Design, Larson & Pranke pgs. 660-663 – MATLAB code to come shortly
HAB Power Systems Trade Study • Solar / Windmill / Flywheel Distribution • Currently used in Antarctica • Extreme environment proven operation • You pay a mass penalty for a flywheel & windmill to sustain power • Windmillling & flywheeling are viable options, but they come at a cost of approximately 2 mt 1,5 • Utilized during wind storms; Mars has 1% atmosphere, but power from wind is a function of velocity cubed 5 • Only 4x faster wind for same power req 5 • Magnetic flywheel is still unproven technology • Nuclear power system (EP) available on surface has excess capacity – no additional IMLEO mass from existing architecture for HAB.
Power Systems Trade Study • Battery Power vs. Regenerative Fuel Cell • Fuel cells are advantageous for Martian surface because of low dry mass and high fuel content on the surface. • Higher battery recharge efficiency make them optimal for space use, especially with solar satellite arrays. • Primary batteries are order of magnitude lighter than rechargeable batteries and could be advantageous for short term taxi missions
Cited References • 1 Larson, Wiley J. and Linda K. Pranke. Human Spaceflight, Mission Analysis and Design. Ch. 20. McGraw Hill. • 2 “PEM Fuel Cell Cost Status.” Carlson, Eric, et al. November 2005. Available online. http://www.fuelcellseminar.com/pdf/2005/Thursday-Nov17/Carlson_Eric_392.PDF • 3 "The status of handling and storage techniques for liquid hydrogen in motor vehicles." Peschka, W. International Journal of Hydrogen Energy, Vol. 12 Issue 11, pgs. 753-764, 1987. • 4 “Atmospheric Climate.” University of Washington. Fall 2002. Available online. http://www.atmos.washington.edu/2002Q4/211/notes_greenhouse.html • 5 “Conceptual Design of a Martian Power Generating System Utilizing Solar and Wind Energy.” Zimmerman, David, et al. University of Houston. Available online. http://www.lpi.usra.edu/publications/reports/CB-979/houston.pdf