Sierra Lobo proposes to develop a technology that can provide both cooling and electric power generation using heat. When coupled with a radioisotope heat source, the technology is ideally suited to the needs of a long-lived Venus lander. The heat source powers Sierra Lobo's Thermoacoustic Stirling Heat Engine (TASHE), which is directly coupled to a Pulse Tube Refrigerator (PTR) in a duplex configuration. A linear alternator, also directly coupled, generates electricity. This configuration reduces the number of energy conversion processes and thus maximizes efficiency. The PTR cools a space called the coldbay that houses the linear alternator and scientific instruments. The only moving parts in the system are free pistons that tune the resonant frequency, which operate at Venus-ambient temperature, and the linear alternators that operate near Earth-ambient temperature.The system can potentially be used with the gas from the atmosphere of Venus, which is primarily composed of CO2, as a working fluid. This provides two key advantages: (1) The system can make the transit to Venus in a low-pressure state, which significantly decreases system mass, and (2) the effect of leakage during operation is minimized, providing confidence in long mission lifetime.
Potential NASA Commercial Applications: (Limit 1500 characters, approximately 150 words) The proposed technology would significantly improve energy conversion efficiency for space power systems and enable a unique capability of simultaneously generating electrical power and refrigeration. The main application for NASA is the Venus lander that will require this duplex capability but in a much more extreme environment. However, any NASA space power program that requires the generation of electrical power from solar or nuclear sources will be able to transition this technology to accommodate the energy source. NASA will be able to take advantage of the TASHE driver with no moving parts at the hot end and efficiency as high as any power conversion system currently in use. Another NASA application for this technology is for ground support equipment for cryogenic propellant densification or zero boil-off where long life, highly reliable compressors will be required to operate cryocoolers.
Potential NON-NASA Commercial Applications: (Limit 1500 characters, approximately 150 words) Potential non-NASA applications include power conversion systems that would use solar concentrators. These applications could include satellites for in-space applications and ground-based power generation stations. Department of Defense applications are similar but may use nuclear sources for heat generation.
Technology Taxonomy Mapping: (NASA's technology taxonomy has been developed by the SBIR-STTR program to disseminate awareness of proposed and awarded R/R&D in the agency. It is a listing of over 100 technologies, sorted into broad categories, of interest to NASA.) Conversion Models & Simulations (see also Testing & Evaluation)
