Organic Rankine Cycle

Organic Rankine Cycles (ORCs) power plants are gaining ever increasing interest as cost-effective sustainable energy systems.

By using an appropriate organic working fluid in a Rankine thermodynamic cycle, ORC power plants are able to efficiently convert renewable energy sources into electricity.

Their power capacity spans from few kWe to few MWe for a single unit, but multiple units in parallel can make up a multi megawatt power station.


Among the multitude of applications of this technology, several stand out: ORC systems can be used to obtain electricity from low temperature geothermal reservoirs, biomass combustion and gasification, solar radiation, waste heat recovery from internal combustion engines and gas turbines, as well as a large variety of industrial processes discarding heat at low and moderate temperatures.

Rankine cycle is a process of converting heat into shaft power. Organic Rankine Cycle (ORC) is a process of converting heat into shaft power using organic material as the working fluid.

The process consists of
(4-1) Pumping of working fluid
(1-2) Extracting of heat by the working fluid
(2-3) Expansion of the working fluid to generate shaft power
(3-4) Cooling of the working fluid

The organic Rankine cycle-based power system is an advanced binary cycle system that is driven by a simple evaporation process and is entirely enclosed, which means it produces no emissions. The only byproduct is electricity, and the system’s “fuel” -- geothermal hot water -- is a renewable resource.

PureCycle geothermal systems have been in operation since 2006 at Chena Hot Springs Resort in Alaska, as a U.S. Department of Energy Geothermal Technologies demonstration project. It is the first geothermal project in Alaska and the lowest temperature geothermal resource (165° F) ever used for commercial power generation.

The PureCycle system makes it possible to tap into a significant new domestic renewable energy resource because it operates at previously unusable low temperatures -- from 165 to 300 degrees Fahrenheit.

The Raser/UTC Power plants are manufactured in modules which offer the following advantages:

Premanufactured for economy in high volume
Delivered and deployed rapidly avoiding costly on-site engineering delays
Flexible modular design can be connected into larger power generation "farms"
The entire plant can be operated remotely, with no personnel on site.
Raser plans to use many of its high efficiency Symetron motors and generators in each 10-megawatt plant to improve output efficiency and reduce parasitic losses.

Utc_purecycle_module_2Raser’s can use a patented liquid heat carrier that has a substantially lower steam point or “flash point” than water. Water boils at 212° F while the liquid used by Raser is effective at temperatures as low as 180° F.