Ramgen Novel Generation
The Fossil Energy R&D program is committed to searching for promising new ideas for low-cost, low-pollutant power generation. Three Ramgen technologies are under examination: 1) the Rampressor, a compressor product; 2) the Rampressor-Turbine, a combination of the Rampressor with the combustor and turbine stages of a turbine engine to gain compression advantages in generating electricity; and, 3) the Ramgen Engine which maximizes the use of ramjet technology to produces electricity.
The Rampressor-Turbine engine
The design of the Ramgen compression technology represents a unique application of well-established ramjet principles to air and gas compression. In an aerospace propulsion ramjet, air is ingested into the engine inlet at supersonic speeds caused by the forward motion of the airplane or missile. The air is rammed into a smaller opening between a center-body and the engine sidewall generating a series of shock waves. These shock waves compress and slow the air to subsonic speeds while, at the same time, dramatically raising working flow pressure and temperature.
A comparable effect is achieved in a stationary platform by passing an accelerated flow of air over raised sections machined into the rim of a rotor disc. Combined with high rotation rate of the rotor, this produces a supersonic flow relative to the rotor rim. Interaction between the raised sections on the rim (which are rotating at supersonic speeds) and the stationary engine case creates a series of shock waves that compress the air stream in a manner similar to ramjet inlets on a supersonic missile or aircraft. There are several important characteristics of Ramgen’s compression technology:
- the process is more efficient than other compression technologies;
- the technology is relatively simple and products utilizing it are expected to be inexpensive to build and maintain;
- the technology is designed to produce a compressor and engine smaller and lighter than competing technologies; and
- the technology is designed to be scaled over a range from 200 kW to 10 MW.
As a result of these characteristics, Ramgen’s shock wave compression technology has the potential to be used in many applications: as an air and gas compressor for industrial processes; in refrigeration and air conditioning; on gas pipelines; as a gas compressor for high pressure gas turbines; or, as a replacement for an axial compressor on the front stage of an industrial gas turbine. Approximately 17% of the electrical use in the U.S. is for compression, and DOE has identified increasing efficiency in compression as a priority. The Rampressor is projected to increase efficiency in comparably sized compressors by 10 percentage points or more. Due to the small size, low weight and the elimination of the intercooler, the capital and maintenance costs are expected to be lower than current compressors. The Rampressor Turbine Engine is projected to be available in a 200 kW to 5 MW size range, achieve 40 percent plus simple cycle efficiency in all sizes; have less than 5 ppm NOx; be small, quiet, and reliable with capital costs in the range of $500 kW of capacity; and have an exhaust heat flow resulting in system efficiency of 80% or higher in combined heat and power applications.