Monday, February 13, 2012

White Paper: Overview of Cool Energy’s SolarFlow TM System

Background: Since the fall of 2006, Cool Energy, Inc. (CEI) has been developing the SolarFlow
TM System, in which an advanced electricity generation unit with a marketing name of the
SolarHeartTM Engine is used in conjunction with rooftop solar heat collectors to supply clean, cost-effective heat and grid-connected electricity to homes and small commercial buildings. This SolarHeart Engine electricity generator is the core technology advance developed by CEI; its function in the SolarFlow System is to generate electricity from the heat that is collected by the solar thermal collectors, delivered into the circulating heat transfer fluid (HTF), and circulated through the engine. The SolarHeart Engine can also be used to produce electricity from other mid-temperature (100-300°C) heat sources,including geothermal heat and industrial waste heat flows.

The SolarFlow System gathers solar heat energy at very high collection efficiencies, and the
heat is then used to provide the majority of the space heating, water heating and electricity
needs of a home or small building. The thermal storage tank integrated with the SolarFlow
System provides operating versatility, as heat can be delivered and electricity can be produced
well into the night or during cloudy conditions that limit energy generation from other solar
energy systems, including solar PV.

SolarHeart TM Stirling engine. The valves in the system are controlled by the SolarSmart Controller
TM to deliver the energy to the sub-system(s) that maximize customer value.

In the SolarFlowTM System, grid-connected electricity generation and heat delivery is digitally controlled by the system’s SolarSmart ControllerTM, which can operate according to a user-configurable program or can receive signals from smart electrical grids that allow it to maximize customer savings. In the winter, the heat gathered by the solar thermal collectors and stored in the HTF is used mainly to heat the home. In the summer, when the collected solar heat is far in excess of the building thermal energy needs, the heat is converted to electricity by the SolarHeart Engine. In the transition seasons of spring and fall, the SolarSmart Controller allocates heat where it is most economical: home heating, water heating, thermal storage, or electricity production. The simple thermal storage tank, filled with HTF and useful during all seasons, provides flexibility for the controller to direct the system to produce the most beneficial form of energy at the optimal time. By fulfilling the need for both thermal and electrical energy from a single system, the SolarFlow System
produces much more customer value than other clean energy options.

The SolarFlow System will annually provide 85% of the space and water heating, and 60% of
the electricity needs of a home or small commercial building. Grid-connected electricity
generation is digitally controlled and can take signals from smart electrical grids that allow it
to maximize customer savings. Direct customer payback times are projected to be less than
half that of solar PV technologies installed at $6/Watt-peak.

Further, the SolarFlow System enables distributed power production in areas where grid
connection is not feasible, or is cost prohibitive to install. Finally, the modular nature of the
SolarHeart Engine provides the capability of using it with other low-mid temperature heat
sources such as geothermal or lower temperature waste heat from existing industrial systems;
much of which at present is not used and therefore wasted as a relatively free and abundant
energy source.

The solar energy equipment industry is currently growing rapidly in all sectors: small-scale
distributed energy systems, industrial and community scale systems, and central station
generating facilities. In the long run, Cool Energy intends to address all three markets, but the
focus for initial commercialization is small-scale heating and grid-connected electricity
generation. This market segment was selected because of the relatively low barriers to entry: a
large population of early adopters, a willingness to accept medium-term economic payback (as
demonstrated by residential solar PV economics), and a growing market for clean energy systems.

Commercial offerings to this initial segment will be of two types: 1)

SolarFlowTM System packages, which will include the SolarHeart Engine, the SolarSmart Controller, solar thermal collectors, a storage tank, and all plumbing components; and 2) SolarHeartTM Engine kits,which will include only the SolarHeart Engine and the SolarSmart Controller for certified installers to integrate with a selected mid-temperature heat source in a home or building. The CEI product roadmap includes increasingly higher-power engine designs for larger solar, geothermal and waste heat applications in commercial buildings and industrial settings, eventually to include utility generation applications with further advanced higher-efficiency engine designs.

Customer Benefits:

Because nearly all Americans use electricity and heating fuels in their homes and the buildings in which they work, the economic and practical value of the SolarFlow System is multi-fold: 1) heating fuels and their associated rapidly rising costs are displaced; 2) electricity generated from fossil fuels is replaced when the capacity of the system to generate heat is not fully needed; and 3) the system’s storage capacity and control system allow for heat delivery and/or electricity production when other current renewable energy systems are otherwise limited.

Target customers for the SolarFlow System are owners of homes or commercial buildings in cold
and reasonably sunny regions of the country, and in particular those burdened with relatively
higher heating and electricity costs. The Northeastern U.S. is the ideal target domestic market for
these reasons as they depend on expensive fuel oil and propane for much of their heating needs.

Eastern portions of this region have a reasonably high rate of year-round solar insolation, public
perception notwithstanding. Other initial target domestic markets are the mid-Atlantic states and
Northern California, to be followed by the Rocky Mountain, Northwest and Midwest regions
because of the relatively hight customer economic benefit. International target markets include
middle and Northern European nations, Japan, and other cold weather regions where sensitivities
to cost are among the lowest and rates of adoption of solar energy projects among the highest.

Due to its ability to offset both heating and electricity costs, direct customer payback times from a
SolarFlow System installation are projected to be 7-15 years in volume production, less than half
that of solar PV systems. A comprehensive analysis of the cost benefit of using a SolarFlow
System in various regions of the US has been conducted, and is set forth in Table 1. The heating
and electricity costs avoided by use of a SolarFlow System are compared with the costs avoided
with a PV system where only electricity costs are displaced. The analysis was conducted by
employing an hour-by-hour system performance model that includes received solar radiation,
home heating loads and losses for a large home, and ambient temperature data to calculate the
reduction in heating fuel and electricity costs realized by use of the SolarFlow System in that
region, and similarly reducing the electricity costs avoided in the same region with a PV system.

All energy cost data are from the Energy Information Administration, solar and weather data are
from the Department of Energy, costs of the SolarFlow System are based on current costs of the
purchased components, and SolarHeart Engine cost projections are shown in the finance and
revenue section below.

Societal and Non-Commercial Benefits:
Energy production has become an integral and important part of all industrial societies. Heat engines have long been used to produce mechanical and electrical power, typically from high-temperature heat sources such as hydrocarbon combustion, nuclear fission, or nuclear radioactive decay. A problem with nearly all current systems used to generate energy is that they result in by-products which
negatively affect the surroundings and often the health and well-being of people. Thus, it has
become increasingly evident that the need for cleaner and less damaging sources of energy is
paramount. Renewable energy systems adopted at a significant rate have the potential to
eliminate these problems. The SolarFlow System for combined heat and power generation
provides pollution free heat and electrical power that can be tied into existing electrical utility
grids, or can be operated on a distributed basis which is of particular significance to developing or remote regions without current access to utility power lines.
Business Model:
Cool Energy intends to manufacture and distribute SolarHeart Engines and SolarSmart Controllers in the first phase of commercialization with the goal of achieving maximum penetration of renewable energy systems through a profitable business. The long background in successful component and machine manufacturing by Dr. Sam C. Weaver will be particularly applicable in guiding this transition. Licensing the SolarHeart Engine and the SolarSmart Controller to others companies for their own manufacturing and distribution will also be pursued at competitive royalty rates, particularly when initially targeting overseas markets. CEI manufacturing operations will initially be located in the United States, and may remain in the US even through high volume production depending on US wages, overseas shipping costs, and the cost of raw materials. It is expected that assembly of pilot units will be completed in Boulder, Colorado and after the process and design are fully established,
manufacturing will be transferred to the Southeast or Midwest regions of the US. An established energy systems corporation will be actively sought by CEI for a manufacturing and distribution partner as the preferred means for greatest penetration of the SolarFlow System in the worldwide market. It is conceivable that entering non-exclusive OEM licensing arrangement through multiple energy systems companies could also achieve this desired impact.

Should CEI initially choose to manufacture the products without a partner corporation, both
internal operations and contract manufacturing arrangements will be considered. Sales and
distribution of the SolarFlow System and SolarHeart Engine will be through both direct and
indirect channels. The indirect channels will comprise sales to solar and energy systems
distributors such as GroSolar, SunWize and Next Generation Energy, who in turn supply solar
thermal systems installers, green builders, HVAC installers, plumbers, and home developers.

With widespread adoption, customers in this channel may also eventually include solar PV
systems installers. Another indirect sales channel will be through retail home improvement
stores such as Lowe’s and Home Depot to supply DIY installations. Direct sales will be to
customers that can purchase large single shipments or commit to an ongoing purchasing
arrangement that meets annual quotas. Examples of these customers include production
homebuilders such as Pulte Homes and KB Homes, and smaller green developers doing a
single large project. Pricing to distributors and direct purchasers will be on the same pricing
schedule based on volume.

Sales offerings will include the SolarFlowTM System package, complete with solar thermal
collectors, the SolarSmart ControllerTM, a storage tank, and associated plumbing components; or alternatively will include only the  SolarHeartTM Engine component of the system with the
SolarSmart Controller for certified installers or individual enthusiasts to integrate with a selected mid-temperature heat source at a home or building. Cool Energy will host a certification program so that national and international distributors and installers may be certified on system installation, which will serve to activate the product warranty.

 This approach to quality control through indirect distribution channels is modeled on the program implemented by Sharp Electronics for their solar PV product installers.

Marketing activities will include attending numerous green building, HVAC, energy, and
renewable energy conferences and advertising in business and trade journals to introduce the
product and to educate consumers on the benefits of this convenient, affordable, zeroemission,
single system with an attractive return on investment. Trade shows being considered include Solar Power 2009, National Association of Home Builders National Green Building Conference, Green Build International, and the ASHRAE Air-conditioning, Heating, and Refrigeration Expo. Other forms of targeted marketing will include outreach by direct mail and email to regional green builders, plumbers and HVAC installers, as well as press releases to regional and national general and business publications such as newspapers and other journals.

Cool Energy, Inc. is registered as a C corporation in the State of Tennessee. CEI is a privately held technology development and solar services company founded in March, 2006 by members of the Weaver family. The company founders were motivated by a passion to create a future in which energy is generated from abundant and environmentally sustainable sources using clean, cost-effective, reliable power systems. The founding team of Dr. Weaver and his son Samuel has a strong materials science and applied physics background, and significant commercialization experience. A decision was made to address the historically difficult and relatively lightly-researched subject area of extracting electrical energy from medium grade heat (100 - 300°C). CEI’s business strategy is to produce cost-effective thermal-to-electric energy conversion devices that take advantage of sophisticated material choices to optimize performance at temperature differentials produced by solar thermal collectors, industrial waste heat, and geothermal heat and biomass combustion.


Cool Energy currently has eight employees in management and technical positions and engages several consultants as needed for software development and engineering projects.

Its main facility is located in Boulder, Colorado. Sam C. Weaver, a founder, currently serves
as Chairman, and Samuel P. Weaver, also a founder, serves as President and CEO. The staff
is composed of two senior mechanical engineers, two additional mechanical engineers, a VP
of business development (Glenn Booth), a VP of legal and Policy Affairs (Leslie Weise) and
an office manager/accountant. Biography summaries for the employees, as well as for the

Board of Directors are included below.
The management team is headed by founder, Chief Scientist and Chairman Dr. Sam C. Weaver, who has worked in the advanced materials industry for over 40 years. Launching his first company in 1970, he has served as President and CEO of nine companies over 35 years. In 2001, Dr. Weaver completed the sale of Millenium Materials to Dyson Group PLC, and previously sold U.S. Nuclear to Eagle-Picher. The majority of the companies Dr. Weaver has overseen have been manufacturing operations, ranging from value-added advanced raw materials to automated high-temperature furnaces with digital control systems.

Dr. Weaver’s son, Samuel P. Weaver is also a founder of CEI and serves as President/CEO,
responsible for engineering management and business operations. Sam previously co-founded
Colorado Photonics, a profitable optical telecom equipment distribution business, and has led
multiple engineering development efforts with complex systems engineering requirements similar to the  SolarFlow System. Sam holds a B.S. in Engineering and Applied Science from the California Institute of Technology and was appointed in 2007 to the State of Colorado Clean Energy Development Authority.

Leslie Weise is VP of Legal and Policy Affairs for CEI. Leslie has nearly twenty years of experience as an engineer and in-house lawyer for Fortune 500 technology companies such as Redback Networks, Applied Materials, Honeywell and Xerox. In addition to advanced degrees in Environmental and Natural Resources Law and Policy and in Intellectual Property Law, her experience includes oversight of M&A activity for AlliedSignal/Honeywell and as General Counsel of NPTest, a spin-off of Schlumberger.

Glenn Booth is VP of Marketing and Business Development for CEI and most recently served as VP of Marketing for the Rajant Corporation, where he led the development and execution of the company marketing strategies and communications. Glenn has over 25 years of successful marketing, sales and engineering experience. Glenn has earned a B.S. in Electrical Engineering from the University of Colorado and is a member of the American Marketing Association.

The senior engineering team is well-seasoned and diverse in experience, and includes Brian Nuel and Lee Smith, who collectively have over 40 years of mechanical and thermal systems design experience. Additionally, two junior engineers, Kevin McWilliams and Nat Farber assist the senior team through engine and system assembly and validation tests on the prototypes. Other engineering, software and design consultants are retained by the company as required for development.

Technical Advisors:

Advisors for the engine and system design and development to date include: Lennart Johannsen, a Stirling engine design consultant, formerly of Phillips and STM; Professor Israel Urieli of Ohio University, a noted Stirling engine specialist; and Jefferey Hodgson, mechanical engineering professor at the University of Tennessee.

Business Advisors: John Herrick has extensive renewable energy experience in technology,
law and policy as Chief Counsel for the DOE EERE and at one the nations’ top energy law
firms, Brownstein Hyatt Farber Schreck, LLP.
Pavel Bouska (Advisory Board) has extensive technology and business operations experience
taking startups through IPO (Gaiam, Inc. & Corporate Express, Inc.).

Andrew Goldstein has strong experience in developing new technologies into cost effective and high quality mass producible products (ProStor Systems, Network Photonics & Medtronic Navigation).

Background of CEI’s Innovations: Several factors have growing impacts on American consumers, their pocketbooks, and their awareness of the current energy situation:
  • Costs of heating fuels such as natural gas, propane and fuel oil have greatly outpaced therate of inflation over the past ten years (7-11% annual increases, with increases more than double that amount in each of the past two years).
  • Space and water heating comprise about 50% of the average American’s annual total energy bill, an even higher percentage in many regions of the country, and growing rapidly.
  • Awareness is increasing regarding energy issues and related national security and climate change impacts. Distributed solar energy installations have been growing rapidly,particularly solar photovoltaic (PV) for generating electricity, and solar thermal for hot water and space heat.
  • Distributed solar thermal systems have high collection efficiencies (up to 75%) and cost about $1.50/Watt-peak installed, while PV systems have much lower collection efficiencies up to 20% and cost about $7.00/Watt-peak installed.
  • Despite the demand for home heating that is affordable and clean, the main barrier to widely-deployed active solar thermal heating systems is their inability to use the excess heat that is generated in the non-heating season and the lack of payoff (i.e. value) of the equipment during that period.
  • Widely prevalent heat sources exist in the low to mid temperature range (100-300°C) that are not being harnessed for energy production, and that are renewable and pollution free such as solar and geothermal, or are otherwise being wasted from industrial production facilities generating waste heat.
These drivers, coupled with the founders’ expertise in advanced materials and engineering development and their concern over the nation’s energy and climate change issues, led to the
founding of Cool Energy, Inc. Considering the widespread and cost-effective availability of
medium-temperature heat sources and solar collectors, the challenge that arises is to make economic use of the heat and/or convert it to another useful form of energy. Methods of conversion of heat to motion and thus electricity are relatively limited in concept: Rankine and Brayton cycles that require fluid expansion and compression and often involve phase change dynamics, solid-state thermoelectric materials with their very low efficiencies, or Stirling-cycle engines. Focusing on the latter for its ability to theoretically approach the limits on conversion efficiency, a technical opportunity was recognized to use advanced non-metallic components in a compact engine design to improve performance and reduce costs relative to traditional approaches. Detailed computer simulation supported higher conversion efficiencies and superior economics from this approach, and the SolarFlow System was conceived and analyzed, showing much promise from a performance and cost perspective. The SolarFlow System integrates the engine, generator, collectors, and storage tank under intelligent control to offer a single, distributed system that fulfills the public’s basic need for low cost electricity and heat without generating any emissions. Further, the customer’s solar ‘fuel’ costs are fixed at zero with this system, leaving them with less exposure to the price volatility arising from depleting fossil fuel supplies. The potential for increased social and environmental health benefits from a system with these capabilities are extraordinary.
The engine design uses plastics, ceramics, metals and glasses in unique, patent-pending subassemblies
to optimize the heat-to-electricity performance for the available temperature range.
The engine is integrated with an active solar thermal heating system driven by evacuated tube
solar collectors for homes and buildings in cold-weather climates. The high-efficiency solar
collectors gather the heat from the sunlight and transfer it into a circulating heat transfer fluid,
which is directed by a series of computer-controlled valves to the system component where it has
the most economic benefit: space heating, water heating, thermal storage, or Stirling engine
electricity generator. The pilot engines are being designed for 1 kW e maximum output power. A
key difference between the SolarFlow System and the standard PV system is that the SolarHeart
Engine can be run off of the heat stored in the storage tank well after the sun sets. This means
that the 1kW rating for the SolarHeart Engine produces much more power than a 1kW solar PV
system. While a PV system is producing electricity about 17% of the time, the SolarHeart Engine
will be producing energy on average about 45% of the time. From simulations, in New England a
1kW SolarHeart Engine with a 300 gallon storage tank will produce as much annual electrical
energy as a 3.5 kW PV system.
Assuming the success of the proposed development and commercialization of the SolarFlow
System, CEI will be positioned to offer an integrated system for the low-cost, zero-emissions
supply of heat and electric power for both residential and commercial applications. Its
SolarSmart Controller will enable optimization of the system output to utilize greater heat
output in colder parts of the day or year, or greater electricity output in warmer periods when
electricity needs typically exceed those for heat. Additionally, SolarFlow Systems can be
multiplexed to cost effectively address the electricity and heating needs of large commercial
Technical Progress to Date:
Cool Energy’s engineering development has focused on two main areas: medium-temperature Stirling engine design, assembly and test and control system design, assembly and test. In addition to simulating and measuring the component assemblies being evaluated for use in the Stirling engine, CEI has successfully demonstrated the mediumtemperature P1 engine prototype as an operating heat engine, producing 300 watts of electrical energy from a 200°C temperature differential, and operating at a peak of 9% thermal efficiency. Successful operation of the innovative P1 prototype engine producing significant amounts of electrical energy clearly demonstrates the feasibility of using non-metallic materials in the engine construction as was envisioned at the project outset. As of July 2009
the P2 prototype engine is in final assembly stages, all parts delivered for this 1.5KW prototype. Simulations and modeling as well as early testing indicate that this latest engine design has the potential for 18% to 21% thermal conversion efficiency. The pre-prototype control system hardware has been deployed on a home with a solar thermal system located west of Boulder, CO and is in a testing phase in preparation for initial pilot system installation in mid-2009.
Cost Models:  Cool Energy has developed two different cost models for the two different
products it plans to offer. The SolarFlow System cost model uses pricing for the purchased
component that are available currently in the US, with the exception of the solar thermal collectors, for which it uses pricing that is currently available through bulk purchasing through Chinese suppliers of evacuated tube collectors. The SolarHeart Engine and SolarSmart Controller are included as separate components in the SolarFlow System cost model. Because the appropriate SolarFlow System will be sized to suit each specific home size, insulation, insolation, and geography, the actual costs will vary by customer.
The other cost model carried at CEI is for the SolarHeart Engine itself. Quotations were requested from key vendors for all components and sub-assemblies used in the engine, and placed into a hierarchical bill-of-materials with all costs rolled into each sub-assembly. The SolarHeart Engine projected materials cost in quantities of 100 units/month was estimated, and together with production labor and controller cost is $5,000 COGS per engine.
Competition for the SolarFlow System includes fossil fuels sources for heat and electricity, including oil, coal, natural gas, propane; nuclear energy for electricity generation; and most directly includes renewable energy sources. The pollution, mining, security, and health issues of fossil fuels and nuclear are well established and thus are not repeated here.
Other companies are involved in developing Stirling engines, though only one has been identified that is developing an engine for the same lower temperature applications as CEI: Etalim, Inc. is pursuing the same business model as CEI, although it is believed they are further behind in development than CEI. There has been some recent development with Stirling engines for lower temperature applications in academia, including at U.C. Berkeley and at King Mongkut’s University of Technology in Bangkok, Thailand, however, we are not aware of any plans for commercialization from these research efforts. ReGen is another company developing low-temperature Stirling engines for waste heat recovery applications.
The remaining Stirling engine companies are developing systems in the traditional high temperature range (600°C – 1000°C). These companies include: WhisperGen of New Zealand which uses a Stirling engine for natural-gas-combustion combined-heat-and-power applications. Rinnai in Japan and Enatech in Europe appear to have licensed a Stirling engine design from Infinia for a natural-gas-combustion combined-heat-and-power system. Infinia of Kinnewick, WA is developing a high-temperature (~1000°C) 3KW solar thermal tracking dish-Stirling engine for electricity production in the community and utility market. Stirling Energy Systems of Phoenix, AZ is developing a high-temperature (~1000°C) 25KW tracking dish-Stirling engine for electricity production. Sunpower, Inc. is developing a 1KW Stirling engine for natural-gas-combustion combined-heat-and-power applications. Kockums of Sweden manufactures 25 KW natural-gas-fired Stirling engine generators for silent submarine applications.
Aside from Etalim and ReGen., the CEI approach to Stirling engines is quite different from the remainder of companies identified as involved with Stirling engine development. CEI designs at lower temperatures to take advantage of low-tech renewable energy technologies. While a penalty is paid in potential efficiency achieved, costs are minimized, and the fraction of the available efficiency that can be achieved is maximized. Because cost, not energy conversion efficiency, is the ultimate arbiter in the marketplace, very favorable economics are forecast for this product.
One competing approach that has become known in the last two years is to cool flat-plate PV panels with fluid or air, and use the heat collected in the building. PVT Corporation, among others, is developing a system to accomplish this end. There are several interesting reasons to attempt this combination, but it is the opinion of CEI engineers that there are serious shortcomings to this approach, especially for space heating applications. This opinion is shared by other industry experts.
Intellectual Property: To date, Cool Energy has filed seven patent applications with the U.S. Patent and Trademark Office pertaining to Stirling engine and system development -- Der Minassians and S. R. Sanders, “A Magnetically-Actuated Resonant-Displacer Free-Piston Stirling Machine,” 5th International Energy Conversion Engineering Conference and Exhibit (IECEC), 25–27 Jun 2007.
Bancha Kongtragool, Somchai Wongwises, “Performance of a twin power piston low temperature differentialStirling engine powered by a solar simulator” Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Laboratory (FUTURE), accepted 27 November 2006.
Lane, Tom; Solar Hot Water System –Lessons Learned 1977 to Today; Energy Conservation Services of North FL, 2004: “This is great for getting a government grant, but a violation of the basic design principles of both systems.”
Additional patent applications are currently being prepared for filing. The company’s patent counsel has performed various patent searches and to date has not discovered any patents that would impede CEI’s ability to make, use and sell its SolarFlow System. A significant advantage to this particular development and commercialization effort is that the foundational prior art for high temperature Stirling engines has existed for many decades, and is thus open to the public domain. Other than in academia and Etalim, Inc., mentioned above, CEI is not aware of any other development in the low to medium temperature range and therefore believes it has full freedom to operate in this technology and product space. Further, because the company continually considers its innovations for patent protection, and is committed to seeking maximum legal protection, it believes it will be well-positioned to prevent other companies from reverse-engineering its product by enforcing its own patents against companies who may attempt to copy its design.


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