Energy conversion efficiency increases
with the engine size,
and most engines perform better at optimum design rpm and load.
Utility levels out individual demand and gain on distributed units efficiency...
Quasiturbine in Public Utility
Utilities do have at least 2 advantages over distributed
power conversion equipments. They can level off the demand which allows to
select equipments to produce the optimum efficiency; and second, they group the
needs of several of their customers, and can this way increase the size of their
equipments, which generally lead to direct efficiency and environmental
Their efficiency is specially striking when compare to the
transportation problematic, where vehicle average efficiency from the well to
the wheel barely reach 10% (gas engine top efficiency could momentarily reach 30% only when
at high engine power). For the same barrel of petrol, utilities will make 5
times more mechanical energy available to their customers. Of course, their
forms of energy suffer from a lack of mobility (...or rather capability of storage in
Steam power is staging what may prove to be the
biggest grass-root 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 come at a better time.
Since the Quasiturbine is a pure expansion engine
(which the Wankel is not, neither most of other rotary engines),
it is well suitable as steam engine.
Since the Quasiturbine is an hydrostatic turbine (instead of aerodynamic),
it is also well suited for co-generation project with saturated steam.
Steam Quasiturbine has great potential for
utilities, specially with fossil fuel steam, cogeneration and geothermal low temperature heat and
near saturated steam. On the other hand, the detonation Quasiturbine engine is a
rare concept potentially able to mach the utility efficiency and environmental
cleanness the distributed way.
In energy conversion equipments, working temperature differential is synonym
of efficiency, but could also mean more nitrogen oxide pollutants, and extra
cleaning cost. For this reason, moderate to low temperature steam are getting more and more
attention today. Unfortunately, conventional turbines require very specific high
steam quality and flow to be efficient, which make them almost useless with
moderate temperature steam, often near saturation.
This is where the Quasiturbine steam engine takes over, because it is not an
aerodynamic machine, and its efficiency is optimum at all pressure, load and
rpm. Furthermore large Quasiturbine of several Mega-Watts can be operated at the
same very low rpm of the generator, suppressing the need of costly gearboxes.
What is worthless for some may be valuable to others. This is the idea about
co-generation where the temperature cascade can be match to several
applications, like turbine, Quasiturbine, drying process and finally district
heating... Everyone served on the same barrel of petrol! Large scale utility
co-generation is most interesting, specially in urban and industrial areas.
Distributed small scale co-generation is more challenging and more naturally
scaled to human living style. It is presented on a different page.
Passive geothermal uses the immense stable underground heat sink where heat can be stored or
removed at convenient cost through heat pumps. The reverse Quasiturbine Stirling act as
heat pump for this purpose. Active volcanic geothermal can generate high
pressure water fit to drive an hydraulic Quasiturbine, or even produce steam fit
for the steam Quasiturbine. Still better, geothermal heat could be upgraded
economically by burning some fossil fuel, and then be converted more efficiently into
Because the nuclear reactor core is sensitive to temperature difference, it
is used to add heat to high pressure water at almost constant temperature. This
is the best which can be done for now, but with the consequences that the steam
is quite low in temperature compare to coal or fuel burning stations, and
turbine conversion is not as efficient. The Quasiturbine is in fact more
appropriate for such an intermediary steam temperature conversion, partly
because the Quasiturbine can accept steam condensation without damage. The
Quasiturbine is listed as a nuclear steam technology by the INIS © International Atomic Energy Agency.
Large Size QT Steam
What would be the size of a 4000 HP Quasiturbine? First order of magnitude
scaling shows the potential of the low rpm Quasiturbine steam for large size
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 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 follow:
|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. In practice, divide the torque and power by 2 to account for the form factor
would provide more realistic results.
This shows also potential for other applications like in marine or locomotive
Quasiturbine HCCQT? Very
high efficiency gas turbine electrical power plants use a Combined Cycle Gas
Turbine CCGT to reach efficiency of about 55%, because (1) it uses the heat from the gas combustion cycle to turn a turbine
and (2) it uses the residual heat to generate steam for a steam turbine cycle.
These are quite high tech sophisticated pieces of equipment with limited live
span time and further, they are accompanied by high maintenance cost.
Quasiturbine power plant, there would be also two cycles. In the first cycle, a
Quasiturbine would be used as an internal combustion engine to
generate electric power. The sensible heat from the first cycle would then be
run through a heat exchanger to generate steam in a boiler for the second cycle.
Because of similar Quasiturbine's unique ability to run on combusted hydrogen and
steam, in the second cycle, steam would provide motive force to another Quasiturbine's, thereby increasing overall fuel efficiency. Furthermore, the Quasiturbine
center being empty, the internal combustion (IC) and Steam Quasiturbines can be
one the same shaft, with a simple ratchet coupling, and the torque will be
cumulative on one single electrical generator! The interesting point (from a
capital cost standpoint) is that it does not require two different systems, as
with the natural gas turbine and the steam turbine do with a CCGT. The Quasiturbines
would function as both a gas turbine (first cycle) and as a steam turbine
Thus, in principle, one could have a Combined Cycle Quasiturbine CCQT.
The fuel efficiency of the CCQT would probably be less than a true CCGT (55%)
but more than the Quasiturbine alone (33%) which can run at higher internal
gas temperature because of early adiabatic expansion mechanical conversion. This
type of efficiency would actually be more than a fuel cell stack, which, despite
some claims to higher efficiency, is only about 35% at most from raw fuel, and
quite costly on lifetime maintenance. For small unit, the combustion cycle
could be combined with the Quasiturbine-Stirling cycle, which with a spoon of
water can also work as a closed circuit steam engine.
Rotary Pressure Regulator
Gas Pipeline Expander
Gas Pipeline Pressure Energy Recovery - Rotary Pressure Expander
What about an "energy recovery rotary pressure regulator" ? An
interesting application of the pneumatic Quasiturbine is to recover the
pipeline high pressure energy at local distribution stations. Instead of
using a conventional pressure regulator (an energy dissipative device), a
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.
Enhance efficiency of LNG liquefaction cycle.
Engineering Thermal Physics. Conventional pressure regulators cause all the
gas from the constant high pressure side to expand, and the gas pressure-kinetic
energy at the needle is converted into undesirable heat, thereby reducing the
amount of cold produced. The Quasiturbine rotary expander allows for individual
chambers to expand at a variable reduced pressure during expansion, and
therefore reduces the transformation of the gas' kinetic energy into destructive
heat. Furthermore, the Quasiturbine mechanically recuperates the gas'
differential pressure energy, which can be used to run more compressors and make
more refrigeration... for double the energy efficiency gain! This offers a
great enhancement to the thermodynamic cooling machine, especially in high power
LNG - Liquid Natural Gas liquefaction stations. Of course, this efficiency
enhancement is also available for more modest cooling systems and air
conditioning equipment. With
Quasiturbine rotary expander, the efficiency of a gaseous only (like dry
air) system reaches almost the efficiency of a phase change liquid-gaseous
sophisticated phase change chemical products often environmentally unwelcome are
not anymore needed.
Other Utility Uses
Steam purges energy recovery. Since the industrial wide-area networks
vapor boiler cannot be modulated
quickly in power, these boilers generally produce some "steam surplus" to
satisfy the fluctuations of demand which can reach 5 to 10% of the
total capacity. When the steam call does not require this supplement, it
is generally purged without purpose. However, the use of one or several
Quasiturbine steam at the point of purge would allow to recover a part
of the energy and to produce by intermittency compressed air or electricity...
Steam pressure reduction station. Also, a Quasiturbine placed on a
steam line can act like a
volumetric governor according to the power extracted, and better still, it
can also act like a station of reduction of steam pressure for the various
stages of the industrial processes, while recovering the unused energy.
Pumping steam-water condensate.
Quasiturbine used in turbo-pump mode
is particularly well adapted to pump steam condensate from steam injection in one of the Quasiturbine turbo-pump
Hydraulic to Pneumatic Conversion
waves sweeping through a fix caisson pressurizes the confined air, then
relaxes it. These pressure variations can be directed toward both a
pressurized tank and a vacuum tank. This conversion from hydraulic to
pneumatic allows to conveniently drive pneumatic Quasiturbine (almost in
closed loop) between both
reservoirs, avoiding dirty water flow or icing conditions into the energy
system. A similar pneumatic conversion can be done from any water head dam
by dropping the water in a closed tube, and so compressing the confined
air, and later letting the water go while creating a vacuum (Essentially
still a fix caisson which is alternatively flooded and drained to simulate
a large wave effect). Active ports management when at high and low
pressure water level (opening the loop when the air flow become negligible) can further improve the efficiency.
Other systems using Venturi water draft tube (siphon type) can also produce high vacuum
air flow. These can be a very attractive solution for energy independence
in vicinity of small rivers, where all the energy system equipments can be located
Since a water head of 32 feet (10 m) correspond to 1
atmosphere pressure (14 psi), this conversion generally involve pressure
in the range of 20 to 60 psi, a secure level where efficiency is fairly good
Wind to Pneumatic Conversion
are not without environmental problem. The concept of a vertical airplane
wing (no moving part, except for alignment) producing high pressure on one
side and low pressure on the other side, can generate at ground level an
important air draft which could drive a Quasiturbine. Such air draft
amplifiers could be alternative in some systems.
Why Quasiturbine steam and solar energy?
Quasiturbine - Comparative efficiency
Quasiturbine Rotary Expander
International Association for the Advancement of Steam Power
Quasiturbine listed at
INIS © International Atomic Energy Agency
Steam-Powered Quasiturbine in Direct-Drive
Railway Locomotive Propulsion