NASA SBIR 2003 Solicitation


PROPOSAL NUMBER: 03- II F3.01-9934
SUBTOPIC TITLE: Thermal Control Systems for Human Space Missions
PROPOSAL TITLE: High Efficiency Refrigeration Process

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
David J. Bergeron
2700 E. Executive Dr., Suite 100
Tucson, AZ 85706-7151
U.S. Citizen or Legal Resident: Yes

It has been proposed by NASA JSC studies, that the most mass efficient (non-nuclear) method of Lunar habitat cooling is via photovoltaic (PV) direct vapor compression refrigeration. This system uses a thermal radiator, a solar PV array, and a vapor compression refrigeration device. Such a system significantly reduces total system mass as compared to an all radiator cooling architecture. Since the start of initial prototype testing in the mid 1990s, several refrigeration systems have been proposed, studied, built, and tested. The basic goal of each system has been to achieve the highest possible efficiency at the optimal system lift. Most notably, a two-stage refrigeration system and an expander turbine for a single-stage system were developed. Both sought to eliminate or recover the energy loss associated with irreversible expansion at the throttling valve, but both fell short of efficiency targets. Then, Paragon proposed a novel refrigeration architecture that was successfully demonstrated during the Phase I period. This system can achieve, in theory, near Carnot efficiency limits and does so in a practical and achievable way. Not only can this technology provide significantly improved performance (reduced weight) for NASA's Lunar habitat cooling application, but it has excellent potential as a commercial product.

The target commercial users are those companies that currently use two-stage refrigeration technology for high-lift, high-power industrial and commercial low temperature applications, especially those applications located in a warm ambient. A few specific examples include: grocery stores operating freezers, transport refrigeration trailers, and potentially Liquid Natural Gas (LNG) and other gas liquefaction plants. Seeking out these customers will be done with the assistance of the two-stage compressor manufacturers, who are also likely to be the long-term licensee of this technology.

The target NASA application is the Lunar base primary cooling system. Lunar base scientific and food freezer refrigeration is also a potential target market. With further development, this technology can be used in similar microgravity applications. Modeling and analysis show that the Batch Cycle technology will reduce the mass of the Lunar base cooling system by 14%, or 500 kg.