Application advantages could be as
precious as intrinsic engine ones.
Engine efficient is just the beginning of a saving cascade.
Quasiturbine offers optimum efficiency with a variety of fuels and modes.
engine / expander description page.
Internal combustion is
completed by a presentation at
Gas expander theory and efficiency is covered at
Where is the Energy Wasted?
Engines do not create energy, they only transform it
into mechanical energy with some inevitable losses. Physics imposes
thermodynamic losses to energy transformation which cannot be circumvent,
but engine losses are more important than the minimum the physics is
In internal combustion engine, the energy is lost in
several ways. Vacuum intake of the gas engine is responsible for about
half of the gas consumption in today vehicle (hybrid concepts are trying
to harvest some of that, while detonation engine could eliminate this
loss). Inhomogeneous diesel fuel mixture is catastrophic to combustion.
Partial combustion in gas engine is also a lost. Internal engine
accessories like cam shaft and valve train are reducing the net available
engine power. Thermodynamic imperfect machine cycle is also a substantial
lost. Lubrication friction is taking an other 3%. Scaling down engine is
not helping either...
Large utility plants convert energy more efficiently
than small distributed units and should be favored when possible. The
detonation Quasiturbine engine is one of the very few long term means to
match utility efficiency the distributed way, while being as chemistry
clean as possible.
Internal combustion residual pressure:
Once the piston get to BDC, it cannot extract any further pressure energy.
However, the combustion gas pressure is still present and flushed out. At
that time, back pressure has not negative effect on the piston while in
BDC. This is the residual combustion pressure the turbo (or pressure
exhaust QT) is designed to recover, and fortunately, higher is the initial
piston mixture pressure (higher engine power), higher is this residual gas
combustion pressure. Same happened within IC Quasiturbine.
Engine Exhaust Heat Recovery:
By placing a hot Quasiturbine into or around an engine exhaust pipe, and
injecting pressurized hot water (steam keep in the liquid state for better
heat transfer), some heat can be recovered into mechanical energy.
Stirling and short steam circuit Quasiturbine could do similarly!
Relative to the pressure flow energy conversion role
of the Quasiturbine, the efficiency (not an absolute efficiency) is given
by the (power or torque obtained) divided by the (power or torque which
could be obtained according to formula), which is typically between in the
80 % efficiency as of 2009.
A Cascade of Savings
Engine efficiency is a large
domain of activity which extends far behind engines. The presence of an
engine in a vehicle adds accessories and weights which have to be carried
by the power of that same engine (the net usable power is reduced by the
presence of the engine itself). The presence of the engine is a necessity,
but also a factor of inefficiency. The ideal vehicle would not bother to
have an onboard engine! This shows that not only engine efficiency is
important on the bench test, but must also reduce to the minimum its
self-inefficiency in application. It would be worthless to have a 70%
efficiency gas engine for mobile application, if such a 30 HP engine would
weight 3 tons! This is one of the paradox of today hybrid vehicle concept:
How much additional equipment can be added to a vehicle to reach the point
where this equipment has worthless net saving effect in actual
Because the Quasiturbine reduces the weight of typical vehicle power
train by over 50%, it does not have to claim any extra efficiency on the
test bench to be most valuable. Such a reduction of weight on the lifetime
of a vehicle means substantial reduction in power demand, and consequently
However, the Quasiturbine has several intrinsic efficiency characteristics
which add up, and reduce the engine energy lost in several ways:
- Because it does not have internal accessories to drive, like the
piston cam shaft and valve train, additional energy is available to the
- Because of the shaping of the volume pressure pulse, the
thermodynamic of the Quasiturbine can be far superior.
- Because the engine weight is about 1/4 that of a piston, energy
saving can be substantial in many applications.
- Because the Quasiturbine is a high torque low rpm engine, much less
or no transmission gears ratio are needed with corresponding efficiency
- Because the Quasiturbine can be of large size, it is an efficient
alternative to utilities for efficient energy conversion (steam) in
electricity or from co-generation.
- Because the Quasiturbine (AC model with carriages) has the potential
to run in detonation mode, it will not have the low power penalty of the
Beau de Rocha (Otto) cycle, which can provide a 50% energy saving in
transportation application (much superior to hybrid concepts).
Multi-fuel capability is also an important efficiency factor permitting
to use the most pertinent local combustible. Hydrogen high compatibility
is also of consideration for the future.
Such small and efficient Quasiturbine steam engine makes mobility possible.
Thermal solar steam could drive a Quasiturbine. Solar concentrator could
directly heat up a Quasiturbine engine bloc, which would act as evaporator,
super-heater and motor! It could also be used for small geothermal or industrial
At home, combine electricity and heating would be possible from several
sources, sometimes with complementary higher temperature source.
Quasiturbine Stirling could be made cylindrical and be inserted directly into
the chimney for optimum heat recovery.
Engine Exhaust Heat Recovery:
By placing a hot Quasiturbine into or around an engine exhaust pipe, and
injecting pressurized hot water (steam keep in the liquid state for better heat
transfer), some heat can be recovered into mechanical energy. Stirling and short
steam circuit Quasiturbine could do similarly! Same technology could apply to:
Industrial exhaust gases heat recovery
industrial furnace heat recovery
Industrial process heat recovery
Chimney or stack heat recovery
Waste heat recovery
Solar heat recovery
Geothermal heat recovery
Thermal nuclear heat
ORC (Organic Rankine Cycle)
Engine suitable for ORC (Organic Rankine Cycle) in Solar, Geothermal and
Waste Heat Recovery.
Efficient at All Loads
The benefit of power modulation is precious. Pneumatic, steam or
combustion turbine engines all have one major limitation: Their efficiency
depends of the load, the rpm, the power... They have to be operated at
their design condition to meet their optimum efficiency at a given working
power. Because the Quasiturbine is not an aero- or hydro- dynamic engine,
but a static pressure type of engine, it has an optimum efficiency on a
large range of power, load and rpm. This allows for efficient uses in
power modulation applications with optimum energy saving and efficiency.
The Quasiturbine is consequently a superior gas expander and most suitable
for efficiency difficult steam co-generation projects.
Piston Beau de Rocha (Otto) gas engine and the diesel engine have
similar optimum power regime limitation. Only the detonation engine has
Quasiturbine as an Immediate Solution
Engines are at the end of the energy chain and they affect the most the
energy users. More efficient engines not only save fuel, but any bit of
saving has direct amplified impacts on all anterior stages of the energy
cascade and industry.
pneumatic Quasiturbine will rotate under the pressure differential and the
flow will be controlled by the rpm, i.e. the torque applied on the
Quasiturbine shaft. It does act as a dynamic active rotary valve. This
way, the Quasiturbine can transform the pressure differential into useful
mechanical work to run pump, compressor, ventilator, electricity generator
or locally convert the energy in high grade heat (better than pre-heating
the gas before that same "rotary expander", to avoid any residual
condensation as done with conventional regulators). Substantial heat is
now given to conventional expansion valve in pure lost, while heat given
to the gas at the intake of a rotary expander is essentially all recovered
in mechanical energy or electricity. Because conventional turbines can not
be widely modulated in rpm and load, they are not suitable for gas flow
and pressure control, while the Quasiturbine is essentially a closed valve
at zero rpm, and has high efficiency at all torque and all flow rpm. With
such a system, any heat added before the Quasiturbine expands the gas and
increases the available volumetric flow with the result that this heat is
converted in mechanical energy with a very high efficiency. All
experimental demonstration has to be done only by gas experts and under
all current rules and regulations. Ignoring gas expansion and considering
only the gas pressure flow, a 36 inches diam. gas pipeline at 700 psi
carry typically a pressure power in excess of 30 MW - 25 millions of
pound-ft/sec - of zero pollution pure mechanical energy almost totally
recoverable through Quasiturbines in the heart of cities and industrial
parks. This is tens of giant windmills on kW-h basis!. A survey (M. Dehli,
GWF Gas-Erdgas 137/4, p.196, 1996) showed that in Germany alone, the
potential for utilizing this pressure in 1996 was 200-700 MW, and the gas
consumption has increased since then... See the
conceptual diagram and a
pipeline technical paper.
Economics: Take any similar fossil fuel
electric generation station, and set the fuel cost to zero, as the
pressure energy recovery does not consume any fuel. It is even better than
renewable, it is free energy, until the utilities start to charge for it,
and make an easy extra income!
Refrigeration: Conventional pressure regulators make all the gas to
expand from the constant high pressure side, and the gas pressure-kinetic
energy at the needle is converted into undesirable heat, reducing
accordingly the amount of cold produced. The Quasiturbine rotary expander
allow for individual chamber to expand at a variable reduced pressure
during expansion, and such reduces the gas kinetic energy transformation
into destructive heat. Furthermore, the Quasiturbine recuperates
mechanically the gas differential pressure energy, which can be used to
run more compressors and make more cold... A double energy efficiency
gains! A single Quasiturbine in tubo-pump (tubo-compressor) mode could
have one circuit used as rotary expander while the other is used to
compress back some of the expanded gas. This offers great enhancement of
thermodynamic cooling machine, and specially in high power LNG - Liquid
Natural Gas liquefaction stations. Of course, this efficiency enhancement
is also available for more modest cooling system and air conditioning
equipments. With Quasiturbine rotary expander, the efficiency of a gaseous
only (like dry air) system reaches almost the efficiency of a phase change
liquid-gaseous system, and sophisticated phase change chemical products
often environmentally unwelcome are not anymore needed.
Quasiturbine Rotary Expander
Intake cut off valve