Preheated combustion air-through recuperators
or regeneration pick up 6%-8% efficiency, for a 24-month or 60-month ROI.
For more than a decade, ORNL had been working with industrial partners to design recuperators
(counter-flow heat exchangers for waste heat recovery) for turbines that can endure high-temperature, wet operating conditions.
It would, however, produce 10 MW of electricity (enough for 8,000 homes), require about 40 MW of recuperators
, a 26 MW C[O.
Overall thermal efficiency is 25%-achieved through high pressure ratios instead of the heavy (and expensive) recuperators
found on most micro gas turbines.
In addition, the scope of the contract includes replacement of the gas turbine skids and auxiliaries, replacing and installing heat recuperators
, installing new control logic functions into the existing controls systems, site installation activities and a full-string test for the first upgraded unit.
The feed stream is preheated in the low temperature (State 2r) and the high temperature (State 3r) recuperators
before entering the evaporator.
More than 50 recuperators
of different airflow capacity were investigated.
Lightweight and compact gas turbines that employ recuperators
to pre-heat combustion air, microturbines operate on the same principle as gas turbines.
Effectiveness of heat recuperators
follow simple correlations with two independent dimensionless parameters for air-to-air exchangers (Kays and London 1984).
Compared to conventional gas turbine generators, microturbines typically have lower electric generation capacities (30 to 500 kW versus more than 1 MW), lower pressure ratios (about 4 versus 8 to 10), radial-flow designs (versus axial-flow designs), and incorporate recuperators
(versus typically unrecuperated designs).
One of Bonney's "Negative Poetix" manifestos in his fine Yt Communication pamphlet Document: hexprogress has it that "ideas that don't become power in liquid form will multiply as land value and finish as cash asbestos in the mouths of freezing moths, understood as academic recuperators
of the avant-garde.
Because microturbines use devices called recuperators
to transfer heat energy from the exhaust steam back into the incoming air stream, they are far more efficient than other small combustion turbines.