Includes specific energy conversion systems, e.g., fuel cells; global sources of energy; geophysical conversion; and windpower. For related information see also 07 Aircraft Propulsion and Power, 20 Spacecraft Propulsion and Power, and 28 Propellants and Fuels. N91-12151*# George Mason Univ., Fairfax, VA. Dept. of Electrical and Computer Engineering. LASER ANNEALING OF AMORPHOUS/POLY: SILICON SOLAR CELL MATERIAL FLIGHT EXPERIMENT Final Report, Oct. 1989 - Jun. 1990 Eric E. Cole Jun. 1990 31 p (Grant NAG5-1294) (NASA-CR-187370; NAS 1.26:187370) Avail; NTIS HC/MF A03 CSCL 10A The preliminary design proposed for the microelectronics materials processing equipment is presented. An overall mission profile, description of all processing steps, analysis methods and measurement techniques, data acquisition and storage, and a preview of the experimental hardware are included. The goal of the project is to investigate the viability of material processing of semiconductor microelectronics materials in a micro-gravity environment. The two key processes are examined: (1) Rapid Thermal Annealing (RTA) of semiconductor thin films and damaged solar cells, and (2) thin film deposition using a filament evaporator.
The RTA process will be used to obtain higher quality crystalline properties from amorphous/poly-silicon films. RTA methods can also be used to repair radiation-damaged solar cells. On earth this technique is commonly used to anneal semiconductor films after ion-implantation. The damage to the crystal lattice is similar to the defects found in solar cells which have been exposed to high-energy particle bombardment. Author N91-12152# Technische Univ., Delft (Netherlands). Lab. for Measurement and Control. AN INTEGRATED DYNAMIC MODEL OF A FLEXIBLE WIND TURBINE Peter M. M. Bongers, Wim A. A. Bierbooms, Sjoerd Dijkstra, and Theo vanholten (Stork Product Engineering, Amsterdam, Netherlands) 1990 122 p (Grants ENW3-0044-NL; NOVEM-41/33-020/10) (MEMT-6; UDC-621.548; ISBN-90-370-00371-1; ETN-90-97753) Copyright Avail; NTIS HC/MF A06 A model to study the dynamic behavior of flexible wind turbines was developed. The different subsystems of the wind turbine are individually modeled with about the same degree of accuracy. The aerodynamic part describes wind shear, gravity effects, unsteady effects, and dynamic inflow. The rotor blades are provided with degrees of freedom in lag and flap directions. The tower construction is modeled including the first bending mode. The first torsional mode of the transmission is included in the model. The model of synchronous generator with do link consists of a nonlinear fourth order model, including saturation effects. The different models of the subsystems are coupled into one integrated dynamic model which is implemented as simulation code in the DUWECS (Delf University Wind Energy Converter Simulation Package) program. The DUWECS program is developed in such a manner that it is an easy to handle tool for the study of the dynamic features of wind turbine systems. ESA N91-12153% Champaign, IL. PERFORMANCE OF AN ICE-IN-TANK DIURNAL ICE STORAGE COOLING SYSTEM AT FORT STEWART, GEORGIA Chang W. Sohn, Gerald Cler, and Robert J. Kedl Jun. 1990 39 p Sponsored by Army Engineering and Housing Support Center, Fort Belvoir, VA (AD-A224739; CERL-TR-E-90/10) Avail; NTIS HC/MF AO3 CSCL 10/4 Diurnal cold storage cooling systems provide an effective means for reducing peak electrical demand at Army installations. The U.S. Army Construction Engineering Research Laboratory demonstrated an ice-in-tank diurnal ice storage (DIS) cooling system at the Post Exchange building, Fort Stewart, GA in April 1987 as part of the Facility Engineering Applications Program (FEAP). Design and construction of the system were documented elsewhere.
The system was instrumented during the 1987 cooling season to test its performance. The system energy performance, peak shaving capability, operation and maintenance experience is documented along with and lessons learned from the Fort Stewart first year system operation. The efficacy of a DIS cooling system as a means of reducing peak electrical demand has been verified; however, generalization of performance for generic ice-in-tank systems is not recommended due to the limited amount of data available from only one system. GRA Army Construction Engineering Research Lab., N91-121.54% Los Alamos National Lab., NM. Advanced Engineering Technology Div. ADVANCED SYSTEM ANALYSIS FOR INDIRECT METHANOL FUEL CELL POWER PLANTS FOR TRANSPORTATION APPLICATIONS Nicholas E. Vanderborgh, Robert D. McFarland, and James R. Huff 1990 9 p Presented at the 1990 Fuel Cell Seminar, Phoenix, AZ, 25-28 Nov. 1990 (Contract W-7405-eng-36) (DE91-000171; LA-UR-90–3356; CONF-901106-1) Avail; NTIS HC/MF AO2 The indirect methanol cell fuel concept actively pursued by the USDOE and General Motors Corporation proposes the development of an electrochemical engine (e.c.e.), an electrical generator capable for usually efficient and clean power production from methanol fuel for the transportation sector. This on-board generator works in consort with batteries to provide electrical power to drive propulsion motors for a range of electric vehicles. Success in this technology could do much to improve impacted environmental areas and to convert part of the transportation fleet to natural gas and coal derived methanol as the fuel source. These developments parallel work in Europe and Japan where various fuel cell powered vehicles, often fueled with tanked or hydride hydrogen, are under active development. Transportation applications present design challenges that are distinctly different from utility requirements, the thrust of most of previous fuel cell programs. In both cases, high conversion efficiency (fuel to electricity) is essential. However, transportation requirements dictate as well designs for high power densities, rapid transients including short times for system start up, and consumer safety.
The e.c.e. system is formed from four interacting components: (1) the fuel processor; (2) the fuel cell stack; (3) the air compression and decompression device; and (4) the condensing cross flow heat exchange device. DOE N91-12155# Naval Postgraduate School, Monterey, CA. POWER RECOVERY OF RADIATION-DAMAGED GALLIUM ARSENIDE AND INDIUM PHOSPHIDE SOLAR CELLS M.S. Thesis Corinne Cypranowski Dec. 1989 155 p (AD-A225307) Avail; NTIS HC/MF A08 CSCL 10/2 Radiation damaging to on-orbit solar arrays was found to significantly decrease power output and efficiency. By a process of annealing, these cells can recover some of the initial performance parameters. Gallium Arsenide (GaAs) and Indium Phosphide (InP) solar cells were subjected to 1 MeV electron radiation by a Dynamitron linear accelerator at two fluence levels of 1E14 and 1E15 electrons/sq cm. The annealing process was varied by temperature, amount of forward biased current, light conditions and time. Both types of cells were found to be hardened to radiation; however, the InP cells were superior over the two. Multiple cycles of irradiating and annealing were performed to observe the amount of degradation and recovery. The results prove that substantial recovery will occur, particularly with the InP cells. Applying this process to on-orbit spacecraft utilizing solar arrays as the main source of power will significantly increase mission life and potentially decrease cost of the on-board power system. GRA
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