The Status of
(revised draft -- feedback appreciated,
send to authors)
In this time of concern over the future
availability and cost of power, the impact of global climate change and
problems with noxious emissions it is important to that we explore all
promising opportunities to reduce the US dependence on energy imports, and at
the same time reduce emissions and costs.
A question then is - Why hasn’t serious consideration been give to the
Double Acting Swash Plate Drive Stirling (da/sh)
engine. It can reduce fossil fuel
use and emissions at a cost competitive or lower than other future power
systems? The da/sh engine can:
·
Produce electrical power at a cost competitive with utility
power plants.
·
Double the miles per gallon of fuel over recent gasoline and
diesel cars and trucks.
·
Reduce energy vulnerability by making it possible to use
essentially any fuel or heat source.
·
Reduce consumption of fossil fuel beyond that of first
generation fuel cells.
·
Avoid the need to create new fuel delivery infrastructures.
·
Achieve environmental standards that are difficult for other
thermal power systems.
·
Cost less to build and operate than other power systems.
·
Be available in volume before other advanced power
initiatives.
The background these assertions is
summarized in the attached papers:
1
Introduction
to the Double Acting Swash Plate Drive Stirling Engines
2
Development of Double Acting Swash Plate Drive Stirling
Engines
3
Applications for Double Acting Swash Plate Drive
Stirling Engines
4
Operation
of Double Acting Swash Plate Stirling Engines
While the
information is presented from a U.S viewpoint, the benefits apply at least as
well to other nations. The economic and technical feasibility of the da/sh engine has been
established. Its commercialization only
requires effective, adequately funded engineering and development.
Attached is also the resume of the
author, Albert J. Sobey.
For further Information contact
Lennart Johansson at Lenstm@aol.com
Al Sobey at AJSobey@cs.com
Additional
information on which these papers are based can be made available on inquiry.
Imperfections
in formatting in this html version are the fault of Paul Werbos, not of the
author(s).
Double
March 2006
In this
time of concern over the future availability and cost of power, global climate
change and noxious emissions it is important that we seriously explore all
promising opportunities to make effective use of US energy resources and reduce
energy imports.
There has
been remarkable success in reducing the fuel use (and emissions) of internal
combustion engines (spark and compression ignition) by improvements in controls
and use of devices such as variable valve timing, superchargers, power on
demand and after treatments such as catalytic converters and particulate traps. Internal combustion piston engines are
approaching their practical (and theoretical) limits of efficiency and
emissions. Attempts to extend their
usefulness are time consuming and costly – in research and product cost.
Fuel cells
(using hydrogen) are still decades away.
While many authorities believe that they will ultimately be technically
and economically viable. There still
are serious technical (and cost) problems to resolve.
The Double Acting Swash plate type
Production da/sh engines can:
·
Produce
electrical power systems at a cost competitive with utility power plants.
Total energy effeteness equal or superior to coal
plants
Competitive costs at Sizes from 5->1.000 kW
·
Double
the miles per gallon of fuel over recent automobiles and trucks.
Equal or superior fuel consumption to hybrids
·
Reduce
energy supply vulnerability by using essentially any fuel or heat source.
Gasoline,
Diesel, Naphtha, Ethanol,. Methanol, hydrogen, natural
gas,
purpose grown and
waste biomass as well as solar
·
Reduce
consumption of fossil fuel beyond that of first generation fuel cells
Minimal energy consumed in fuel processing and
distributions
·
Avoid
the need to create new fuel delivery infrastructures
Can
use or simplify the existing liquid fuel delivery and retail systems.
·
Achieve
environmental standards that are difficult for other thermal power
Meet regulated emissions with little or no after
treatment
·
Cost
less to build and operate than other power systems
At comparable production volumes
·
Be available before other advanced power initiates.
Technical and economic feasibility established.
Commercialization only requires good engineering not
basic research
The fact that da/sh engines have fewer than half the parts of modern
gasoline engines will make it possible to build them at lower cost than
comparable internal combustion engines (at similar production volumes). Most of their components can be produced
using the same processes now used in the manufacture of automobile engine
components – thus reducing capital investment costs – and saving jobs.
The use
of constant process, ambient pressure,
heat input systems makes it possible for da/sh engines to meet environmental standards that internal combustion engines
can not meet economically (or at all in the case of noise). With development da/sh engines may be able to meet 2007 environmental standards
with an open tail pipe (no emission after treatments or mufflers)
The
efficiency of the first test da/sh engines was in the 30-35% range (Btu
in to shaft power out). The first
generation of upgraded JGT da/sh engines will be
in the 40-45% range with the target efficiency of 50-55%. These engines will be more efficient than
practical diesel engines and above the target (set by US Dept of energy) for
first generation Fuel Cells. The
ability of the da/sh engine to achieve these goals is
well established by internal and independent studies (by NASA).
The da/sh engines can be designed for different levels of cost and
reliability consistent with the intended application. Stirling engines for electrical power will be
designed for ten to twenty five years useful life with annual maintenance (Stirling
engines, built in
They can
use fuels with a wide range of energy content and do not require control of
cetane or octane content or energy content.
The simplification of fuel
processing may permit an increase in the yield per barrel of crude oil. They can use much lower Btu gas and are more
tolerant of dirty fuels and air than internal combustion engines. As more da/sh engines are deployed they will make gradual but significant reductions
in fossil energy use, noxious emissions etc.
da/sh engines can be available sooner than
other improved power systems. Serial
production could start in 2 to 4 years for electrical power (after commitment
of the needed resources). Development (and
demonstration) of vehicle propulsion engine will take longer. Serial production could start in 4 to 7
years.
They can
provide significant social benefits.
They can reduce the economic and social costs of serious energy supply
interruptions (accidents, vandalism or terrorism) more effectively than other
power systems. They can. reduce the need for
fossil fuels
First By improving the efficiency of power
generation (vehicle propulsion and electrical power generation and
distribution).
Second By using combustible materials which are not now considered to
be significant energy.
resources (agricultural, urban and indusial wastes etc)
The extent
of their national energy and environmental benefits can be estimated from the
size of the market for engines in the 2 kW to 1000 hp range. Approximately thirty eight million gasoline
and two million diesel engines were produced in the United States during 2005
by about thirty companies (about three times as many are produced overseas - proportionately more diesel engines).
The da/sh engines ability to use low grade or innovative energy
resources (wastes, solar power, geothermal etc) is complementary with the need
to use energy systems that will meet the needs of the growing global economy as
economic fossil fuel resources are exhausted
The da/sh engines
will have a long term future. . They
will make more efficient use of biomass and similar materials (urban and
industrial wastes etc.) than other power plants. They can produce power more effectively from
solar, nuclear or geothermal heat than steam turbines or fuel cells.
The
improved economics and performance the da/sh engines can provide have advantages for:
Owners and Operators of Electrical
Systems and Vehicles
Once their cost and performance advantages are
understood they should become the power systems of choice for base load or
emergency electrical power systems and for most vehicles (5 kW to >1000 hp).Their
ease of operation, performance and economics will be attractive to buyers
Government Energy and Environmental
Regulators
They will be able to meet future energy
and environmental standards that will be difficult for internal combustion
engines. Once their low to negligible (nitrous
oxide and particulate) emissions are understood their use may be, in effect, be
mandated.
Engine and Vehicle Manufacturers
They
will provide competitive advantages in cost, performance and low cost over
conventional internal combustion engines.
.
Development of new engine sizes (5 kW to >500 hp)
will take less time and cost less than equivalent internal combustion engines.
Energy Companies and Fuel Suppliers
They
will simplify the fuel slate and potentially increase the yield of useful fuel
from a barrel of crude oil and extend the life of the resources.
The total
market for da/sh engines may be larger than that of
internal combustion engines. . In 2005
approximately 38 million gasoline and 2 million diesel engines were produced in
the
There are
three primary reasons why the da/sh
First Until
recently internal combustion engines could meet energy and environmental
standards economically. The decision
makers saw no pressing need for a new kind of engine. Some engineers probably considered it a
threat to their authority and knowledge.
Second
There have been many unsuccessful attempts to develop
Third The
efforts to develop commercially competitive da/sh engines have not been adequately funded. Initial
investors had a limited view of its application and avoided developing the
technologies for high risk opportunities.
Lennart Johansson has raised sufficient capital to confirm the engines
technical and economic feasibility – but not to commercialize it. This was accomplished at a fraction of the
cost that would be required for a new gasoline or diesel engine.
The
commercialization of da/sh engines does not require research
breakthroughs – only adequately supported - good engineering and development.
Some of the
advantages of the da/sh engine are summarized on the following table
Double Acting Swash plate
Advantages over Internal Combustion Power Systems Include:
Low Capital Costs
da/sh engine
have fewer than half the parts of comparable gasoline or diesel engines.
An independent study found that da/sh engine based propulsion systems
should cost less than
equivalent internal combustion systems at volumes over 50,000
per year
Low Operating Costs
Can use Low (or negative) cost fuels.
The potential for low maintenance costs has been demonstrated.
Fuel (or heat source) Flexibility
The da/sh engines
can produce power from any source of heat (<700 to 1000 oC)
They can use any liquid fuel (naphtha, ethanol, gasoline diesel)
interchangeably, or any gaseous fuel (natural gas, hydrogen,
land fill gas) interchangeably, as
well as biomass, solar, combustible wastes, waste process heat etc. and solid
fuels.
High Efficiency
They will be as efficient as diesel engines - markedly
superior at part load.
The pre production engines are 30-35% efficient.
The first production engines will be 40-45%
efficient. The target is 50-55% -
High Energy Effectiveness - Resource to Power
The fuels for da/sh
engines do not require control of octane, cetane or foreign material content
thus reducing the
cost of (and energy consumed in) fuel processing and
distribution.
They will provide more kilowatt hours or vehicle miles
per unit original energy resource (oil, natural gas, coal, biomass
etc.) than other power
systems (including first generation fuel cells).
Low Emissions
The da/sh
engine uses a constant process ambient pressure burner (or heat input system). They can have very low
NOx, no measurable unburned hydrocarbons, CO, or
particulates - without after treatment
da/sh engines can meet some environmental standards (for
emissions and noise) with an open tail pipe.
Rapid Response
Idle to full throttle 1/3 second using variable swash plate (no emission peak) and will start easily.
High Reliability
150,00-200,000 miles for cars 1,000,000 + for trucks
25 to 50 years for electrical power, based on
thousands
of hours of operation in
intermittent
controlled explosions as with internal combustion engines.
Low Noise
Comparable to household appliances - Less than 58 db
at nine feet.
Can be designed for near zero noise, heat and electronic signatures
Ease of Manufacture
The da/sh engine has no
intake or exhaust valves, ignition only required for starting etc.
Most of the parts can be produced using similar manufacturing process
to those used for automotive piston engines.
Competitive weight and volume
Similar volume to equivalent diesel existing engines
(less when smaller transmissions are included).
The existing engines (assuming 6000 rpm for propulsion) weight 2.5 lb/ hp.
The target is 1.5 lb/hp
Availability
Volume production of
da/sh engines only requires good well supported engineering – no
research breakthroughs.
They can be available in volume within the time
required to develop high efficiency, low emission internal
combustion engines and much sooner than fuel cells
Development of
Double
March 2006
The
concept of the
The
availability of da/sh engines for electrical power
generation and vehicle propulsion should benefit most companies and users in
the power and vehicle communities.
Commercialization will require a much expanded effort – but is not
dependent on technical or research “breakthroughs”. Given adequate resources da/sh engines can be available in volume about as soon as the next
generation of internal combustion engines and much sooner than fuel cells.
The
development of modern
The next
major effort was that by United Stirling Company (
United Stirling
Some of the
family of kinematic Stirling engines that United Stirling designed have been
commercialized one (the V-160) by SOLO Kleinmotoren Gmbh a second (the 4-95) by
Stirling Energy Systems Inc. as well as by Kockums (the 4-275). Kockums installed
Lennart
Johansson managed the Unites
In 1977 Lennart Johansson was asked
to come to the
In the
process the rights to the 4-95 test engine were
acquired by
Lennart
Johansson acquired the rights to the underlying technologies.
Three
sizes of the Double Acting Swash plate drive external Heat
(da/sh) engine were designed at STM Power
Inc. two under Lennart Johanssons direction (including the 4-70 for hybrid
drive, the 4-120 (25-30 kW) designed for use with land fill gas. He provided the basic design of the 4-260 (55
- 60 kW) before creating
When STM’s Board decided to
concentrate on production of da/sh engines for use with landfill gas (in
2003) Lennart Johansson created Johansson Global Technologies (JGT). His objective was to create and expand the
center of technical excellence for
Lennart Johansson has managed the
development of the da/sh engine in the
We do not
have adequate information to provide defense be estimates of how much the
deployment of the da/sh engine will reduce energy dependence
– with confidence. It should be a
significant improvement – a supplement to any other energy strategies. Some insight can be gathered from the size of
the internal combustion engine market.
In 2005 nearly 40 million internal combustion engines were built by US
industry for a wide variety of markets. da/sh engines could replace gasoline and diesel engines in essentially all
markets they now dominate as well as induce new markets.
The next
stages in the da/sh engines development will include:
·
Design
and demonstration of a family of improvements that will increase the
effectiveness of da/sh based power systems
·
Adapt
the heat input systems to use non traditional fuels and reduce cost and weight.
·
Adapt
the engine design to a range of potential applications - small and large power
plants, commercial, personal and recreational vehicles etc.
·
Conduct
demonstrations to confirm the performance and reliability of the new generation
of da/sh engines for a range of competitive applications.
·
Initiate
sales to the markets for producing power from traditional and non traditional
fuels.
Assuming adequate resources the first generation of da/sh engines for distributed power should be available in two to
three years. It will take 4 to 6 years
to complete development for propulsion and release them for use in
vehicles. Operational demonstration of
the first generation of da/sh engines (coupled with reliability
and performance experience in electrical power) are expected to be required to
obtain the support of the automotive community
The
relationships between the principal
da/sh
Not shown are
the license Philips granted GM and Ford.
Both attempted to develop vehicle propulsion versions of the rhombic
drive engines.
There are two versions of the da/sh engine one
with a fixed swash plate and one with a variable swash plate. Only the variable swash plate version has the
power response characteristics required for vehicle propulsion (or electrical
load following).
Other
companies have worked on
Applications for
Double Acting Swash Plate Drive Stirling Engines
October 2005
In theory da/sh engine could replace internal combustion engines in nearly
every market they now dominate. This
could provide benefits for all sectors of the electrical and automotive
communities.
Their use will reduce
cost of ownership (purchase, operating, maintenance)
Manufacturers can use, or
adapt, the same processes used to produce internal combustion engines.
They will reduce the
costs of fuel producers and avoid major expenditures for new infrastructures.
They will make it easier
to meet energy and environmental regulations
They can be adapted to a
large number of applications
They are easy to operate
da/sh engines can use essentially any
source of heat provide (combustion of liquid, solid or gaseous fuel, waste
process heat, solar energy). Their
total costs (purchase, fuel and maintenance) will be similar to or lower than
competitive systems. Their high
efficiency, low emissions make it possible for da/sh engines to meet energy and environmental standards that other power
systems find difficult. Their low noise
and vibration levels make it possible for to install da/sh engines in places where internal combustion engines are not
acceptable
Public and
Private decision makers need to know how competitive power systems compare in basic
terms: (use of existing fuel resources, emissions, life, cost and performance) The relative order of superiority provides
more insight into their potential level of use than projecting if and how much
candidate power systems will change the performance an existing product (i.e. a
Chevrolet Impala or Lexus)
The da/sh engine is divided into three sections which can be used in
various combinations. The heat input
System, the power systems and the power output systems. The same basic power section can be adapted
for the two primary markets by changing the heat input systems, operating
speeds, power output (generators or transmissions). The differences will be driven by fuel
arability, product performance requirements and trade offs between cost and
design life.
A third market - generating cryogenic
temperatures and space cooling is not addressed in this paper.
Its
advantages include higher efficiency, ease of control as well as elimination of
the need for freon type working fluids. Over 5,000 cryogenic systems developed by
Philips are in use by air forces and hospitals to produce liquid oxygen and
nitrogen.
The peak efficiency of existing da/sh engines is 30 to 35% (Btu in to shaft power out). JGT plans to increase the efficiency to 40 to
45% in its first production engines (A NACA study confirmed that 50 to 55% is
feasible). This will require increasing
cycle temperatures to approximately 1000 oC. The high efficiency engines will use low cost
high temperature materials and manufacturing technologies developed in
cooperation with Oak Ridge National Laboratories and suppliers.
Future da/sh engines (55%
efficiency) will be more efficient than practical internal combustion
engines. Da/sh engines only need a source of adequate heat (700 to 1000
oC). Their fuel (or heat
source) tolerance will simplify the process of producing and distributing
liquid (and gaseous) fuels thus reducing the quantity of energy resources (natural
gas, coal, petroleum etc.) required per unit power below that of internal
combustion engines.
Extensive use
of fuel cells that require 99.99+% pure hydrogen would
substantially increase the consumption of natural gas (from which the hydrogen
could be made) or require construction of additional electrical power plants
(to produce hydrogen by electrolysis).
The
capital and operating costs of the da/sh engine will be significantly lower than that of competitive internal
combustion engines or fuel cells. The
first (low production) da/sh engines have a total cost advantage
(acquisition and operating) over modified (spark equipped) diesel engines
operating on dirty (landfill etc.) gases for stationary or distributed power
applications. They can use much lower btu gas and can tolerate variations in heat content and
dirty atmospheres.
da/sh based distributed electrical power
systems will operate for more than ten years between major overhauls and 8,000
hr. between routine maintenance. The
heat input systems can be designed to use any liquid fuel (interchangeably) any
gaseous fuel (interchangeably) as well as solid fuels (purpose grown biomass,
waste, - hazardous or negative value) solar energy and waste process heat. The
480 cc da/sh engine (four 120-cc cylinders) when
optimized for long life produces 24 kW (45 hp) at 1800 rpm (peak efficiency).
da/sh solar hybrid systems can be designed
to produce electrical power (in the Sun Belt) at a cost competitive with
utility power plants. Three
demonstration Solar hybrid systems were installed in
Several
sizes of da/sh engines have been built 280 cc (15
kW), 480 cc (25 kW) and 1040 cc (55 kW).
Collectively they have accumulates over forty thousand operating
hours. The same 480 cc
Existing da/sh engines modified for propulsion (higher operating speeds) will
weigh less than 2.5 lb. per hp (target is 1.5 lb. per hp). da/sh engine for cars will be designed for more than 4,000
operating hours (heavy trucks for 20,000 hr.).
The automotive versions are comparable in size to internal combustion
engines and have superior transient characteristics (ease of starting -
acceleration idle to full power in 1/3 second with no emission spike).
The wide flat torque speed
relationship of da/sh engines make it possible for da/sh engine
base propulsion systems to use transmissions with half or fewer gears than
comparable gasoline or diesel engines.
A class 8 truck with the 1500 cc da/sh engine will get slightly better acceleration and fuel
economy with a manual four speed box compared to a ten speed box with a two
speed rear end.
da/sh engine
based propulsion systems can be designed to operate on any liquid (or gaseous) fuel
that will produce 700 to 1,000 oC.
They can use naphtha, ethanol, methanol, gasoline, diesel fuel and some
unprocessed petroleum interchangeably.
The fuel tolerance of da/sh engines will permit simplification
of the production and distribution of liquid fuels (they do not need high
octane or cetane and will minimize the need for boutique fuels). The use of da/sh engines (depending on market penetration) could make it possible to
optimize refinery yields in terms of the energy content of the delivered fuel
rather than control of cetane or octane etc. to produce a prescribed slate of
gasoline and diesel fuel etc.
Because