Drexel University offers a detailed look at the novel dry-cooling technology being studied to reduce water use at thermoelectric plants. The research team, which includes Drexel, the University of Memphis, Evapco, WorleyParsons and the Electric Power Research Institute, is focusing on phase change material in the form of tiny wax beads:
"The group’s design uses large mesh disks, 20 meters in diameter, woven from quarter-inch-thick tubes filled with tiny bead-like capsules of paraffin just a few millimeters in diameter. The discs would be stacked 15 meters-high in a cylinder the team calls a 'rotary heat exchanger unit.' With the look of a sophisticated water wheel, the unit will have openings on the top and bottom for hot water to flow in, cooled water to drain out and ambient air to keep the system moving.
"As the hot water enters the unit from the steam condenser, the beads in the mesh will absorb the heat. The discs will continue to rotate as the water enters the unit. When the heated portion of the disc reaches the cooling side of the unit, ambient air is pumped in to let the beads release the heat before returning to the atmosphere outside the plant. The cooled beads spin back to the other side as the disc rotates, ready to repeat the process."