Recently Granted and Published Patent: US20110241448 A1


High Efficiency Magnetohydrodynamic Power Generation Using Ultra- High Magnetic Fields And Novel Cooling - United States Patent Application 20110241448


The present invention provides for a high efficiency MHD energy conversion device which utilizes flux trapped in superconductors as permanent magnets having magnetic flux densities of up to 17 tesla, and multistage cooling systems which employ coolants, including liquids with cryogenic properties such as liquid helium and liquid nitrogen. An electrically conductive fluid, in the form of an ionized gas or plasma, flows through an electrically conductive fluid conduit in a magnetic field produced by the pole pieces of two permanent magnets aligned for maximum field density for inducing an electric current in the fluid by separating the positive charges from the negative charges. As used herein, the reference to “permanent magnets” includes superconductors having trapped flux as opposed to electromagnets in which a current is passed through a coil surrounding a ferromagnetic core.

Each permanent magnet is disposed in a chamber containing a cryogenic liquid, e.g., helium, which has been circulated from the chamber through a heat exchanger, releasing the heat absorbed within the chamber before being pumped back into the chamber.

The chamber containing each permanent magnet is sandwiched between two dewar vacuum containers in contact with the cooling chambers of two respective liquid nitrogen cooling systems. Other cryogenic liquids having similar cooling properties may be substituted for nitrogen. Each cooling chamber of one of a pair of inner liquid nitrogen cooling systems is separated from the cooling chamber of a respective microchannel water cooling chamber by another dewar vacuum container. Each microchannel water cooling chamber absorbs heat from a contacting radiation shield proximate the conductive fluid conduit. The foregoing arrangement enables the permanent magnets to operate at cryogenic temperatures in the presence of an electrically conductive working fluid having temperatures as high as 3,000 degrees centigrade for reaching magnetic flux densities of up to 17 tesla substantially increasing the efficiency of the MHD energy conversion device. Cryogenic temperatures below 4.2 degrees Kelvin are possible.

The Co-inventors are Thomas P. Kay, the founder of Concentrating Solar Power Utility, Tulane University Professor Douglas B Chrisey and Rensselaer Polytechnic Institute Professor Yoav Peles.

“In developing this technology, the use of the extremely large superconducting permanent magnets will improve efficiency, and this is even more so when combined with the micro-channel cooling process developed by Professor Peles,” Dr. Doug Chrisey.

-posted on 7/29/2014