US Patent 8184436 Liquid-cooled electronics rack with immersion-cooled electronic subsystems

Liquid-cooled electronics racks are provided which include: immersion-cooled electronic subsystems; a vapor-condensing heat exchanger to condense dielectric fluid vapor egressing from the immersion-cooled electronic subsystems; a dielectric fluid vapor return coupling in fluid communication the vapor outlets of the immersion-cooled electronic subsystems and the vapor-condensing heat exchanger; a reservoir for holding dielectric fluid; a gravity drain line coupled to drain dielectric fluid condensate from the vapor-condensing heat exchanger to the reservoir; an immersed, sub-cooling heat exchanger disposed within the reservoir; a dielectric fluid supply manifold coupling in fluid communication the reservoir and the dielectric fluid inlets of the immersion-cooled electronic subsystems; and a pump for supplying under pressure dielectric fluid from the reservoir to the dielectric fluid supply manifold for maintaining dielectric fluid in a liquid state within the immersion-cooled electronic subsystems.