Geothermal energy* and over 60% of man made energy is wasted as low heat. Converting low heat into effective work is uniquely challenging in the real world as there is simply not enough energy for the desired expansion ratios to take place in the current state of the art heat engines. Currently used steam turbines generating power from low heat application obtain less than 8% efficiency. However, since low heat is typically lost anyway, any and all effective work recovered is deemed positive.
Though turbines are capable of being efficient, they require high temperatures that permit multiple expansion of the steam. But when using low heat/energy, there is sometimes not enough energy to expand more than once. In addition; turbines are not positive displacement and therefore have high leakage rates, have internal frictional losses due to windage/turbulence, have poor efficiency at low HP ratings, part loads or with low energy steam, have poor zero RPM torque capability and require gear transmission.
Steam piston engines are positive displacement which have very low leakage and thus apply all contained energy into producing work. However, the over 200 year old slider crankshafts have mismatched cylinder pressure to optimum mechanical crankshaft angle, resulting in mechanical inefficiency (see attachment). Other positive areas are; capable of using low quality wet steam, have excellent high torque at zero RPM and excellent part load high efficiency and can work without a gearbox.
The market for economical alternative low heat energy power generation is apparent, especially in today’s green market and for remote residential, farming/agricultural and smaller commercial applications. Any and all low quality heat like solar, geothermal, chimneys, exhaust manifolds, low quality combustible bio mass solid, liquids and gaseous fuels are candidates for supplementary heat sources and can be used in any hybrid combination. In addition, many smaller generating units in diverse locations solidly deals with the huge energy losses of up to 20% when passing large amount of electrical energy over the grid at great distances.
This proposed NGEN engine retains the positive displacement attributes and eliminates the inefficient slider crankshaft. It incorporates a linear double action piston, with a proprietary innovation that converts linear to rotary motion and is the key innovation that optimizes torque throughout the entire piston travel. Its modular configuration lends itself to flexible power requirements and is capable of being economically manufactured using standard processes and procedures without the requirements of new materials or technology. The use of modern material science and electronic controls all contribute to the ways and means of increasing efficiency over 2.5 X higher than the current state of the art in generating power with the same low heat energy.
* "Even if only 1% of the thermal energy contained within the uppermost 10 kilometers of our planet could be tapped, this amount would be 500 times that contained in all oil and gas resources of the world."
-U.S. Geological Survey