Turbine Charger
Microturbines
produce both heat and electricity on a relatively small scale by means of
combustion. In general, they offer advantages compared with other technologies
for small scale power generation
Those advantages over reciprocating engine generators include: a small number of
moving parts; compact size; light weight; greater efficiency; lower emissions;
and the ability to operate with a range of fuels (eg CNG and bio-fuels). Waste
heat recovery may be employed with these systems to reach very high
efficiencies.
The majority of a microturbine’s waste heat is contained in its relatively
high-temperature exhaust. The combined thermal electrical efficiency of
microturbines in cogeneration applications where exhaust heat is utilized reach
over 80%.
Turbines offer a high-powered engine in a very small and light package. This is facilitated in part due to the fact that there is no requirement for either water-cooling or exhausts catalytic conversion. However they have a time lag and provide poor fuel efficiencies at low speeds if integrated into conventional propulsion drivetrains.
EREV (Extended-Range Electric Vehicle) hybrids utilizing turbines as the on-board charger will provide all the advantages, as the battery will address the variable power requirements and the turbine will be operating at its “sweet spot”.
In simulation exercises, we have found that the fuel costs for ICE-powered EREVs in typical urban environments will be up to 50% more expensive than those powered by micro-turbine on-board chargers.
The ETVM patent-pending mictroturbine design is expected to outperform the state-of the art microturbines for the following reasons:
- The ETVM mictroturbine will operate on RQL (Rich-Quench-Lean) principles
and will have the unique property of achieving optimum efficiency at two
operating points. This “dual mode” property will provide a number of degrees
of freedom when matching the microturbine to various drive cycles and
vehicle categories.
- Proprietary valving and duct design results in minimal pressure drops
- Advanced heat exchanger/recuperator resulting in ultra-high thermal
efficiencies (>90%) with low pressure drops. (The combined hot and cold
pressure drops will be less than 8.5% of maximum cycle pressure)
- Advanced stator/rotor sealing techniques, resulting in high adiabatic
efficiencies. Implementation of ceramic regenerative heat exchanger and turbine enabling operation at higher turbine inlet temperatures.
The characteristics of the prototype and production ETVM microturbines are presented in the following table.
| P1 | P2 | Production | ||
| Power | kW | 12/45 | 13/48 | 20/60 |
| Efficiency | % | 37-38 | 38-44 | 45-50 |
| Weight | Kg | 120 | 100-110 | 100-120 |
| Rotational Speed | RPM | 80,700 | 80,700 | TBD |
| Turbine Inlet Temp | 0C | 975 | 1,050 | 1,250-1,350 |
| Recuperator | Advanced Metal | Ceramic | Ceramic | |
| Turbine | Metal | Metal | Ceramic |
The P1 turbine, with an efficiency that outperforms the present state of the art by approximately 30%, will be fully functional in Q2 2010.
