Without exception, liquid hydrogen storage tanks experience boil-off which results in a significant increase in propellant costs. Typical storage tank boil-off rates result in a loss of approximately $20,000 per month per tank. Current storage tanks vent this boil-off to burn stacks.AFAB Technologies proposes a low cost, self-acting, liquid hydrogen boil-off recovery system. The system is based on an all-cryogenic, high-speed turboexpander with an overall thermal efficiency in excess of 70 percent and a volumetric efficiency over 90 percent. The system is installed, close-coupled, in-line with the storage tank boil-off vent.The turboexpander uses self-acting, hydrodynamic fluid-film bearings for superior stability, continuous duty cycle, and long-life of 15+ years. Simplicity of design minimizes part count for reduced manufacturing and assembly costs. The entire system will have a low-volume production cost below $20,000 a unit which will pay for itself within the first month of service. This system is responsive to NASA objectives to lower the cost of conducting liquid hydrogen testing by reducing the propellant losses due to liquid hydrogen boil-off.
Potential Commercial Applications:Successful implementation of this program will result in a low-cost liquid hydrogen boil-off recovery system which has ability to pay for itself within the first month of operation. Its market potential is to be installed on every liquid hydrogen storage tank in the United States.
