Patent ID: 7290393

Claim:
An ORC power generation plant, comprising: a motor-generator configured to be switchably connected directly to, and to be disconnected from, a power grid; a circulation path for a working fluid, comprising: a turbine in mechanical communication with said motor-generator and having a fluid inlet and outlet; an evaporator having a thermal input for receiving thermal energy, an input for receiving said working fluid in liquid form, and an output in fluid communication with said fluid inlet of said turbine for providing said working fluid in vapor form to said fluid inlet of said turbine; a condenser having an input in communication with said outlet of said turbine for receiving said vapor from said fluid outlet, said condenser adapted to condense said vapor to said liquid and to deliver said liquid at a condenser outlet; and a variable speed pump for pumping said liquid, said variable speed pump having an input for receiving said liquid from said outlet of said condenser and an outlet for conveying said liquid to said input of said evaporator, said variable speed pump having a control signal input terminal; and a rotation speed sensor for measuring a rotation speed of said motor-generator, said rotation speed sensor providing an output signal; and a pump speed controller for controlling a speed of said pump, said pump speed controller receiving a signal based at least in part on said output signal of said rotation speed sensor and providing a control signal to said control signal input terminal of said variable speed pump; whereby said ORC power plant is configured to start with said motor-generator configured as a generator and disconnected from said power grid.