Steam is a source of energy, specially in co-generation and geo-thermal...
Steam power is more and more prominent in industry around the world.
Steam Quasiturbine could not come at a better time.
Quasiturbine Steam Engine
Quasiturbine Uniflow Characteristic
In most reciprocating piston engines, the steam reverses its
direction of flow at each stroke (counter-flow). By entering and exhausting the
cylinder by the same port, the cylinder valve and walls are cooled by the
passing exhaust steam, while the hotter incoming admission steam is wasting some
of its energy in restoring the temperature. Some energy is further lost in
reversing the motion momentum of the mass of steam within the piston. The aim of the piston uniflow is to
remedy this defect by providing an exhaust port at the end of the stroke, making
the steam flowing only in one direction, but has the inconvenience of
recompressing some residual cylinder steam. Quasiturbine is a uniflow engine,
with the further advantage of not recompressing any residual steam, resulting in
superior energy efficiency. Recompressing residual steam means some
reversibility losses, and the pressure increases makes a substantial restriction
to the initial steam flow into the chamber, not to ignore the truncated cycle
near bottom dead center - None of this with the Quasiturbine.
Quasiturbine has no vane
Unlike vane pumps, which vane extension is important and against which the pressure acts
to generate the rotation, the Quasiturbine contour seals have an
imperceptible extension and the rotation does not result from pressure against these seals.
The vane geometry does not allow high compression ratio at TDC (top dead center), while Quasiturbine does,
and this is why QT is efficient (less pressure charging losses), and this is why there is no vane combustion engine.
Quasiturbine publishes « efficiency data » while vane motor manufacturers don't. Premium on « efficient equipment »
is rapidely recovered in operational cost...
Mechanical Conversion of Low Heat
From looking at the USA energy flow chart at
The amount of Low temperature heat discarded is quite
impressive. This waste energy has a tremendous potential for energy recovery,
and the Quasiturbine offers more ways to tackle the challenge through Brayton,
Ranking and Stirling cycles!
La pression d'un circuit vapeur est déterminer par le point le plus froid (condensation),
alors que l'éfficacité est donné par la température de la vapeur (les
surchauffeurs font une chauffe à pression constante - celle du point froid,
souvent la chaudière elle-même). L'efficacité optimum requiert souvent un
surchauffeur distinct de la bouilloir, laquelle fixe la pression. Coté
efficacité du cycle lui-même, la basse pression de vapeur réduit la demande de
puissance de la pompe d'alimentation en phase liquide, ce qui est pratique mais
pas critique, parce que du point de vue globale, l'addition d'énergie au système
par la pompe est presque totalement récupérée par la turbine...
Mise à part la chaleur latente, l'énergie est essentiellement dans les débits
volumiques, et les débits en phase liquide sont typiquement 600 fois moindre
qu'en phase vapeur.
Souvent, l'optimum est d'utiliser les thermies basses températures comme
préchauffe d'un cycle à plus haute température, au quel cas l'efficacité
différentielle du carburant utiliser pour la haute température est bonifiée...
La QT favorise un cycle vapeur basse pression aussi pour une raison
réglementaire, car les hautes pressions sont dangeureuses et bien exigentes.
Dans le cas de la QT, nous préconisons pour le solaire, de supprimer la
chaudière, et de chauffer le bloc moteur de la QT lui-même, et d'injecter de la
vapeur gardée en phase liquide dans un injecteur pour vapeur éclaire (flash
steam). Pratique aussi pour les unités mobiles qui craignent les réservoirs
Steam power is staging what may prove to be the
biggest grass-roots comeback in the history of the industrial revolution! From micro-horsepower to
Giga-Watts, from microchips to motorcycles, and from wheel chairs to missions to
mars, STEAM POWER IS BECOMING PROMINENT IN VIRTUALLY EVERY INDUSTRY IN EVERY
COUNTRY OF THE WORLD. Steam Quasiturbine could not be at a better time.
The Quasiturbine steam engine does not produce vibration.
Quasiturbine pneumatic-steam model QT75SC (Without carriage)
Usable with intake sustained pressure as low as 20 to 50 psi!
The Quasiturbine steam engine does not make any vibration.
Approximated first order theoretical steam case with a 33 bars (500 psi)
effective differential pressure
at 1800 RPM without any gearbox. This simplified linear extrapolation does not
guaranty that the steam flow will permit to reach 1800 RPM for the larger units.
Preliminary sizing data for Quasiturbine are as follows (no intake cut off):
|50 kW (70 HP)
0,4 MW (530 HP)
3 MW (4 000 HP)
25 MW (33 000 HP)
200 MW (260 000 HP)
|13 cm (5 inches)
25 cm (10 inches)
53 cm (21 inches)
1 m (3,5 feet)
2 m (7 feet)
|5 cm (2 inches)
10 cm (4 inches)
20 cm (8 inches)
41 cm (16 inches)
82 cm (32 inches)
Notice that in 4 strokes internal combustion mode, the
Quasiturbine power is about 1/8 of the one indicated,
increasing almost linearly to this maximum 1800 RPM. Notice that the Quasiturbine power increases
almost linearly with the RPM on a large range.
Remark on Steam Efficiency
An high efficiency steam motor does not guaranty the high
efficiency of the entire steam system. The cooling steam effect during
relaxation must not be under-estimated. For high pressure drop (not allowed with
the prototypes), intermediary heating is a must to keep up the pressure and
avoid condensation. No steam circuit is easy to design and operate.
Quasiturbine can further make internal gas expansion if the dominant restriction
is made to be at the intake, such that the flow is not sufficient to keep the
internal pressure at the level of the pressure intake line. This internal
expansion can then be done without any synchronization valve. Efficiency
increases as the involved gas pressure is lower.
Since water requires an important quantity of latent vaporization heat (which
is not generally recovered in the condenser or in the atmosphere open circuit),
operation with saturated steam will always give low efficiency (5 - 10 %)
(unless with a cogeneration application), because of the important volume
of water which needs to be evaporated to maintain the pressure. Even if the
Quasiturbine can accept saturated steam, it is not suitable from the energy
efficiency stand point, that this steam stays saturated during all the cycle. In
fact, in all expansion thermal machine (the Quasiturbine being one of the most
efficient), increase in thermal efficiency is always linked to steam overheating
(without having to increase the pressure), since then one gets the same pressure
effect with less molecules, wherein making a substantial reduction in the
quantity of water needed to be vaporized (... and saving of the
corresponding latent heat energy, while some more calories are lost in the
exhaust). With an important overheating, the efficiency of the thermal steam
engines can reach and even exceed 50% ... (The overheating may occur in the
steam pipes, or in the Quasiturbine itself). In practice, a tuned conventional
system can have an efficiency exceeding 20%, with direct drive and instant
From the steam engine point of view, no more need for very high pressure steam to be efficient!
The conventional steam turbines require very high pressure in order to generate the high flow
speed permitting the turbine to be efficient. This is not the case with the
Quasiturbine which is very efficient (engine efficiency, not necessarily the
system efficiency) at all pressures, all load levels and all RPM, and can
produce substantial power with sustained intake pressure as low as 20 to
50 psi and at only 1800 RPM. In those two cases however, the super-heated steam
increases the efficiency of the steam cycle, and the lower pressure operation
may lead to larger equipments for the same power... The Quasiturbine greatly
reduces the station construction and operation cost, reduces substantially the
risk, improves the safety level, and reduces the law constraints and the qualifications
needed from the employees.
For optimum performance, the feed line must be well
balanced between the two intake ports, which must be done by ending the line
passed the 2 T by an accumulator (buffer) tank, on which the pressure gage can
The Feed Pump is not a net energy lost
Historically, to avoid feed pumps, the steam boiler was over-designed to hold
sufficient water for a full operating cycle. This is still of interest for the
solar steam systems (or geothermal), ou il est avantageux d'avoir une citerne
d'eau pressurisé en marge du circuit vapeur suffisante pour l'alimentation la
journée entière (remplissage la nuit), justement pour ne pas avoir à injecter
les condensats contre la pression de vapeur. Une seconde citerne peut accumuler
les condensats à la sortie de la turbine à pression atmosphérique, et le
transvasage peut se faire la nuit sans soleil... Ici, la pulsation quotidienne
est obligatoire de toute façon.
Coté puissance spécifique, la pulsation du cycle à haute fréquence impose
l'arrêt du circuit vapeur et la chûte de pression de la chaudière (et son
refroidissement en pure perte), un inconvénient majeur qui fait baisser à la
fois la puissance moyenne et l'efficacité thermique. Voilà pourquoi on revient à
la pompe de remplisage en phase liquide et continue! Many think that the feed
pump in a steam (Rankin cycle) is a system waste of energy, while in fact, most
of the feed pump energy is recovered by the turbine. It is like the compression
energy in a piston engine which is almost all recovered at relaxation, or the
energy of the compressor turbine in a Brayton cycle (jet engine), recovered in
the hot turbine.
Adiabatic versus Isothermal
Since the Quasiturbine is a pure expansion engine
(which the Wankel is not, neither most of other rotary engines), it is well
suitable as compressed fluid engine, including steam engine. Like for the pneumatic,
the steam Quasiturbine includes two circuits, these circuits can
be fed in parallel, or in series by connecting the exit of the first
chamber to the entry of second. By placing an exchanger on this conduit one can add heat and
doing so, the total relaxation in the engine approaches an
isothermal relaxation. Notice that in this case, the pressure differential
between the two circuits will be automatically equalized.
In the conventional turbines, such an intermediate heating is often
done in order to increase the total
power of the machine, without necessarily increasing the efficiency. In other
words, to extract the maximum energy from a very high pressure, it
would be necessary to use a cascade of machines starting with the smallest, each one
reducing the pressure a little and feeding the following one through a
heat exchanger... The old steam
engines used up to 3 machines (or more stages in the case of turbines),
the Titanic had steam engines using 4 stages of relaxation... The MDI air
car for its part suggests to use a very high pressure 3 stages piston
engine. Nothing prevents from juxtaposing 3
Quasiturbines of different dimensions to do still better!
Because the Quasiturbine has 2 independent circuits which can be used in serial,
many could suggest that a single Quasiturbine can acts as a dual equal-size
stages expander with an intermediary heat exchanger (with reduced specific power, unless the intake
pressure is raised). This is not likely to be the case, because the serial
interconnection of the chambers makes the exhaust volume of the first stage to
move into the exact same volume of the intake chamber of the second stage
without making any net additional torque or work (at constant pressure, or even
if an intermediary heat exchanger increases the temperature and the pressure
during the transfer). Because the exhaust and the intake chambers stay at the
same pressure during the transfer, that pressure would not be a constraining
back pressure to the first stage. The final result would be equivalent to give
heat to the exhaust without getting any work out, and would give a neutral role
to the second stage. Characteristics would be similar to the one circuit only
However, experimentation with inter-stages check-valves, intermediary tank, Venturi
pressure phase shift... and super-heater could make it a worth avenue to explore.
The Quasiturbine can further make internal gas expansion if the dominant restriction
is made to be at the intake, such that the flow is not sufficient to keep the
internal pressure at the level of the pressure intake line. This internal
expansion can then be done without any synchronization valve (cut-off intake). Efficiency
increases as the involved gas pressure is lower. The present possibilities have
not yet been tested.
High Temperature Steam
Utilities are the place to find high temperature steam, and the Quasiturbine
is a very interesting option for such an energy station.
Use of superheated steam could be done in one of the
Quasiturbine circuits, while the other circuit could be used to circulate
cooling air (Quasiturbine turbo-pump mode), permitting to extend the
Quasiturbine operation without reaching the material temperature limit.
Co-generation Saturated Steam
The Quasiturbine is an unmatched alternative to saturated steam turbine with
modulated power output.
Like for co-generation, the Quasiturbine Steam is unique for such a low level
Nuclear reactor have very sensitive core and are used to give thermal energy
at almost constant temperature. Temperature level in nuclear power plant are
much less than in coal or heavy fuel station. For this reason, nuclear steam
cannot expand as much before reaching condensation point, and their turbine are
not as efficient. With the Quasiturbine however, full expansion would be
possible to the condensation point, and this would improve the efficiency.
Furthermore, the Quasiturbine can drive a generator without gearbox, one of the
costly element of conventional turbine...
Flash Steam Quasiturbine
In conventional boiler, the heat is capture in large
quantity by the latent liquid evaporation prior overheating, and none is capture
later at relaxation time. By contrast, in flash steam system much less heat is
initially capture while overheating the flow in the liquid phase, but some
additional heat is being capture at the flashing time from the engine bloc. In
both cases, for equivalent power and temperature condition, similar liquid and
heat flows could be involved. To get the most heat transfer in flash steam
system, high pressure maintains a water liquid state into the feed line and
prevent evaporation prior to expansion until it get into the QT, which could be
at a somewhat lower temperature as the heat recovery system may provide heat
gradients. When the steam is released into the QT and expansion takes place, the
pressure of the overheated water is largely reduced and its over-heat is
provided to the latent evaporation, while complementary heat energy is being
captured from the hot engine bloc.
Consider a water feed line pressure of 1000 psia at the saturation temperature
of 544 F. If the water is entering at 100 F, then the liquid temperature rise
would be 544 -100 = 444 degrees F, and about 444 btu per pound of water energy could
be extracted from the source (In one hours time 2545 / 444 = 5.7 lbs of water
per hour per HP. If expansion was to atmospheric pressure, the specific volume
would be would be about 26.8 cu ft per pound, or 26.8 x 7.7 = 206 cu ft per hour
per HP). During the process, the hot engine bloc would provide additional heat
to the expansion. By contrast, allowing the water to boil and evaporate at 1000
psia would capture 3 times more heat (meaning 1/3 of the flow for the same
capture) hg = 1198 btu per pound (Then 2545 / 1198 = 2.1 lbs water per hour per
HP, and expanded to atmospheric pressure, the volume would be 26.8x2.1 = 56 cu
ft water per hour per HP), with an efficiency of the saturated case of about
33%. Flash steam efficiency may not be the best, but
practicability of the system may be much more suitable in mobile applications by
allowing the Quasiturbine to run cooler, without any dangerous pressurized steam
Small Quasiturbine Steam Engines
I - Conventional steam engine - An engine in the boiler!
Because it is an efficient, compact and zero vibration engine, the Quasiturbine
can be located inside the boiler in a very compact and portable way:
II - Hot water injection engine (in-situ evaporation) Flash steam Quasiturbine
Because the Quasiturbine accepts saturated steam,
a positive way to bypass the intake steam flow limitations is
to use the Quasiturbine itself as evaporator.
In this case, the remote boiler becomes a simple hot water tank without evaporator,
and the pressurized hot water taken in a close loop at the base of the tank is brought to
the engine intake,
where droplets of water and oil are directly injected in the expansion chamber,
and consequently evaporated inside the Quasiturbine itself.
In this case, the latent heat of vaporization is also given to the engine by the close
pressurized hot water loop
via a pipe coil enclosing the Quasiturbine.
The exhaust steam goes to a conventional condenser and returns to the boiler.
This option also presents the advantage of requiring a much smaller boiler,
pipes of small dimensions, miniature control valves,
and permits potentially to reach higher rotational speed.
In the case of thermal solar systems, if the internal liquid reserve is large enough for
all the sunshine period,
this operation mode needs only one unique fill up at night !
III - Cold water injection engine
This mode would definitively be unimaginable with conventional turbine, since they react to the speed of steam flow,
which must be pre-conditioned. In fact, if a burner heats the Quasiturbine engine bloc directly, there is no
need of a boiler any more
(The Quasiturbine acting simultaneously as the boiler, the over heater and the evaporator),
and one can then inject cold water (which will be preheated in the injector)
at a pressure superior to the internal maximum working pressure.
Ideal mode for thermal solar concentrator heating directly the Quasiturbine engine bloc !
(This mode is equivalent of using the Quasiturbine engine bloc as a "flash steam generator")
(Notice that a remote heat source could use an un-evaporating fluid like oil or
liquid sodium to transfer heat to the engine bloc).
Because pressure steam only exist for a short time and only
within the chamber (no steam boiler), this alternative is one of the safest in
term of blowing-up, and as potential to avoid most pressure product legislations
and rules, which is today a serious steam project handicap (no qualified steam
expert needed for operation!).
IV - Quasiturbine Stirling and Short Steam Circuit
This is also a way to make an interesting compact portable engine as described on the Stirling page
V - Quasiturbine Brayton Short Air Circuit
Flashing steam into a Hot Quasiturbine is a Ranking cycle (phase change
requiring a liquid pressure pump), but injecting cold compressed air into a Hot
Quasiturbine and letting it expands is like < flashing AIR >, and this is a
short circuit Brayton QT cycle. Similarly to the Ranking which need a liquid
pressure pump for intake, this Brayton cycle would need an external cold air (QT
?) compressor (Notice that the energy given to the compressor is not lost, but
recovered as pushing pressure during the flashing process).
Rotary Pressure Regulator
What about an "energy recovery rotary pressure regulator" ?
An interesting application of the steam Quasiturbine is to recover the high pressure energy at
pressure reduction stations. Instead of using a conventional cooling station,
a steam 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. 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. 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. All experimental demonstration has to be done only by steam
experts and under all current rules and regulations.
Other Steam Applications
Apart from conventional uses as for electric production, marine or locomotive
propulsion, here some interesting steam applications:
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! 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
Solar thermal plant:
Because the Quasiturbine is efficient at different output level, it is most
suitable for modulated power output as solar thermal plant. Direct solar heating
of the Quasiturbine steam is also a major feature for solar concentrator
plant... Be aware that the technical literature contains a lot of statement
referring to system feed pump or piston compression cycle, as a lost of energy:
this is not true, piston compression cycle energy is mostly recovered during
relaxation, as the feed pump energy increases the system output accordingly...
The intermediary reflector can be suppressed
by moving the power pack inward, and heating the QT on the peripheral.
Steam pressure reduction station:
A Quasiturbine placed on a steam line can act like a volumetric governor
according to the power that one extracted from it, and doing so, it acts
like a station of reduction of steam pressure for the various stages of
the industrial processes, without having to cool the steam, remove the
heat, or lose a lot of energy...
Pumping steam-water condensate:
A Quasiturbine used in turbo-pump mode is particularly adapted to pump the
condensed steam (condensate) from pressure steam injection in only one of the
2 circuits of Quasiturbine turbo-pump.
Steam Purge energy recovery:
As the boiler of the industrial steam networks cannot be
modulated quickly in power, these boilers often produce a "steam
supplement" to satisfy the fluctuations of demand which can reach 5 to 10%
of the total capacity. When the demand does not require this
supplement, it is generally purged in total lost. However, the use of one
or several Quasiturbines Steam at the point of purging could allow to
recover a part of the energy to produce by intermittency
compressed air or electricity...
Steam Engine Lubrication
Periodic oil spray needs to be injected into all
engine intakes steam flow. Standard product recommendations start at steam
pressures of 150 to 200 psig (366 to 388 F). The grade of recommended steam
cylinder oil for these conditions is ISO 460 which contains 4% tallow oil.
This is the grade of oil that the “ride-on” locomotive community uses. It
is generally available in 55 gallon drums, but Sulphur Springs Steam
provides it in quart cans. Chevron USA has a relatively new steam cylinder
oil on the market that is lighter in viscosity than ISO 460 by about half
(1103 SUS vs. 2335 SUS @ 100 F). Other steam oil may do as well. It does
not require much oil, and large steam units generally use a separator in
the condenser, and recycle this oil.
A White Paper
Engine Exhaust Heat Recovery with Quasiturbines
Offering Essential Efficiency Characteristics
Why is the
Quasiturbine revolutionizing the use of steam and solar energy?
Quasiturbine Stirling and Short
Steam-Powered Quasiturbine in Direct-Drive
Railway Locomotive Propulsion
Quasiturbine - Comparative efficiency
with other engines
International Association for the Advancement of Steam Power
listed with INIS © International Atomic Energy Agency