Capstone started out developing recuperated turbines for hybrid cars in the late 80's (NoMac), I think they were originally aiming for about 25kW and 30kg (old SAE paper), but that crept up (weight especially) over time, and I believe their C30 weigh more like 100kg with 30kW output at 26% efficiency now.
30kW is ideal for a mid-sized hybrid car - as it allow you to drive indefinitely on a flat road at 120km/hr Capstone C30 achieves about 26% efficiency with the extra gas flow and higher specific heat of burnt fuel going through the turbine as well as relatively low pressure losses through the combustor and relatively high combustion temperatures of 800+ deg C. Brayton and Recuperated Brayton turbines are extremely sensitive to combustion temp and pressure losses so if the peak temp drops to 500-600deg C and you have significant pressure losses in heating the air going through the combustor as well as reduced turbine mass flow and specific heat compared to compressor flow then I expect the overall efficiency to drop to probably below 20% for recuperated and probably only 10-13% for unrecuperated (like Bladeon). Though these are only guesses, and you can compensate for lower efficiency with bigger heavier and more expensive recuperators and hot end heat exchanger to get higher temps, there will be an economic ideal for a cheap heat source like LENR. On 6 February 2012 22:30, Alain Sepeda <alain.sep...@gmail.com> wrote: > Now forgetting about stirling... > > So you clearly thing that with today's technology, > using a turbine is a realistic solution for a serial hybrid vehicle ? > > what is the minimum realistic power of a turbine, at 400C, at 600C ? is > 10-15kW mechanic reasonable? which effciency ? > is 50kW mechanic reasonable... which efficiency ? > will organic rankine turbine have any interest à 400C ? 600C? for cooling > faster? > > note that about the problem I see two tracks for hope : > - when the car goes fast, it consume much heat, but air flow can be used > to cool quickly... if going slower, need less power... could even use a > fan... > - second if thermal evacuation is a problem, maybe on could design the car > to be a good radiator > > does it seems reasonable ? > > > 2012/2/6 Robert Lynn <robert.gulliver.l...@gmail.com> > >> So take an (optimistic) $10k 30kW 200kg Stirling + generator + very large >> radiators (need much cooler temps than IC engines) to the already heavy and >> expensive $5-10k electric powertrain and you can perhaps begin to see why >> stirling is such a non-starter for vehicles compared to: >> Rankine turbine generator + condenser that weighs perhaps 100kg (turbine >> and generator are smaller as operate at much higher speeds) and costs >> probably $3-5k when mass produced. >> Recuperated Brayton (like capstone C30) that weighs 100kg and costs about >> $5-10k when mass produced. >> >> >>
