-Micro-turbines (capstone et al) have low efficiency compressor and turbines and under 100kW probably won't work at all until the temperatures are >600°C, and then only with very low efficiency (<15%). MW scale might get up to > 20%. -Micro steam turbines are very inefficient, (steam's high specific heat requires multi-stage due to blade speed limits) and with small sizes are far more prone to water erosion damage. They also require huge condensers (radiators) unless running total loss with water. -Reciprocating steam engines are at best 20% efficient, and then only for very intricate and large triple expansion engines, same large condenser problem. -Organic rankine is also very inefficient, but by picking a fluid with lower heat of vaporisaion and greater molecular mass (lower specific heat) can get away with single stage. May be best of a bad lot, but again need large condensers. -Stirling cycle is incredibly expensive ($3000/kW @1kW, $500/kW @30kW) and heavy (10-20kg/kW) due to high prescision + no lubrication. Low piston speeds mean big expensive generators. Also big radiators required.
On 19 October 2011 15:21, Jed Rothwell <jedrothw...@gmail.com> wrote: > These links are for piston steam engines. I believe small turbines, or > "MicroTurbines" as they are called, are a better solution. Capstone and > others are developing them. > > - Jed > > > >
