Clean Energy Devices

7/23/2019 Clean Energy Devices

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Cool Energy, Inc. • 5541 Central Ave, #172 • Boulder, CO • 80301 • tel (303) 442–2121 • fax (303) 442–0820

www.coolenergyinc.com

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SolarHeart® Engines Overview

Cool Energy 20kWe Product Development Overview:

Cool Energy has developed an innovative and novel Stirling engine, called

the SolarHeart® Engine, which converts low temperature heat energy

into electricity. The SolarHeart Engine differs from other Stirling engines

because it can use lower temperatures for its heat input (100°C to 300°C)

than typical heat engines. Other currently commercially available Stirling

engines use heat input temperatures in the 600°C to 1000°C range.

Harnessing heat from this lower and previously untapped temperature

range opens an entire new set of renewable and alternative applications

for power generation that were not previously economical. The output

power ranges (3kWe and 20 kWe currently) for the SolarHeart Engine

enable new classes of distributed renewable power systems in

applications such as waste heat recovery, solar thermal electric, and

biomass power. After successfully building, testing, and shipping 3kW engines to prove out the technical

approach to low-temperature power conversion, the next step is to extend the generating capacity up to

20kWe per engine, both increasing capacity and reducing the cost per Watt. Conceptual designs have been

in progress since Q3 of 2012, and parts procurement for the first prototypes is currently in progress after the

final selection of the 20kW engine geometry. The first 20 kWe engine is anticipated to be operational in mid-

2014, with first commercial availability in late 2014.

The SolarHeart® Engine – its applications and contributions to our energy needs:

The primary market application for the SolarHeart engine, due to its rapid payback time, is the recovery of

wasted and exhaust heat to produce electricity. Application environments include commercial and

industrial facilities, remote and military generators, and ship engines, which can all benefit from using theSolarHeart Engine for electricity production. Aside from providing cost savings and reducing emissions from

using less fuel and power, other advantages of the SolarHeart Engine include reducing the need to transport

fuel to remote and military locations, a process that is often expensive and logistically difficult (and for the

military, very dangerous). Among the additional applications for the SolarHeart Engine are the use of solar

thermal, biomass, and geothermal sources for heating and powering homes and buildings.

Development of the SolarHeart Engine began in 2006, and has been supported in part through grant awards

from the US National Science Foundation, the Department of Energy, and the Environmental Protection

Agency as well as contracts from the Dept. of Energy and Colorado Governor’s Energy Office. Cool Energy has

developed historically novel Stirling engines composed of high-surface-area heat exchangers, non-metallic

self-lubricating piston/cylinder sets, and non-metallic regenerators. The design approach employed by CoolEnergy has emphasized reduced cost and high reliability to minimize the total cost of ownership and hence

the cost of the energy produced. Designed initially for operations at lower temperatures and moderate

conversion efficiencies (10% to 25%) for waste heat recovery, conceptual designs have been generated to

extended to higher temperatures in order to increase efficiency for use with natural gas combustion. The

third generation low-temperature prototype produced 2 kWe at 16.5% thermal-to-electric conversion

efficiency when operating at 215 °C hot side and 15 °C cold side temperatures. The fourth-generation

prototype pictured has demonstrated an output of 3.1 kWe at 300 °C input temperature and 20 °C rejection





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temperature with conversion efficiencies of over 22%. Two of the fourth-generation prototype have been

sold to potential market partners and delivered in 2011, with additional units being fabricated currently.

Waste Heat Recovery applications for SolarHeart® Engines1

The SolarHeart® Engine can be used to recover low grade waste heat that has previously been

uneconomical to recover, and boost operational efficiency of a power generator or process:

The SolarHeart Engine can be used with any heat source in the engine’s optimal input temperature range of

100-300 °C. Whereas cost-effective waste heat recovery solutions at higher temperatures (over 500 °C)

already exist, the SolarHeart Engine offers a solution for low grade waste heat recovery from commercial

and industrial processes, from remote and military generators, and from supplemental and backup gensets.

This approach increases the efficiency of operations and reduces fuel consumption.

Figure 1) Axial-drive 20 kW e Stirling engine shown in notional waste heat recovery application. The source of

hot gas flowing through the engine heat exchanger could be a reciprocating engine exhaust stream, or waste

from an industrial process or pollution control equipment.

The SolarHeart Engine boosts the fuel efficiency of a diesel generator when recovering its waste heat:

The SolarHeart Engine can boost the output of a diesel genset by 5% to 10% when recovering the waste heat

the generator exhausts. In remote and military settings where fully burdened diesel fuel can cost up to

$15/gal including transport costs, the payback period for the engine can be under one year. The reduced

requirement for transport of fuel is a highly valuable benefit to the military, as a significant fraction of

modern war-fighting casualties occur during resupply missions of water and fuel.

1 Certain information about waste heat recovery presented in this section has been acquired from the website of the U.S. Department of

Energy Intermountain Clean Energy Application Center – Waste Heat Recovery





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An illustration of the SolarHeart Engine configured to capture waste heat from a genset is included below.

Fig 2) SolarHeart® Engine configured to recover waste heat

The SolarHeart® Engine is efficient, simple in its operation and designed for high reliability

Low to medium temperature (100 °C to 300 °C) Stirling engines are attractive devices for converting lower-

grade heat into mechanical or electrical power. Cool Energy has developed and demonstrated the novel

SolarHeart Engine operating at temperatures in this range with 3 kW e electrical output power, and has

developed designs for producing up to 40 kWe. This type of Stirling engine has several attributes that make

it attractive as a bottoming cycle in waste heat recovery applications, including having a maximum

theoretical thermal efficiency closer to the theoretical limit than other cycles. Operation below typical

combustion temperatures (500 °C - 1000 ° C) enables materials to be used in the engine components that

minimize thermal losses and reduce weight and cost relative to typical engines operating at high

temperatures. Advantages the Stirling engine has over organic Rankine cycle machines include excellent

part load performance, a wide operating temperature range not constrained by temperature restrictions of the working fluid, and high performance at both constant and variable rates of waste heat production.

The SolarHeart Engine is quiet:

Because the SolarHeart Engine operates at a low speed (approximately 600 rpm), has no internal

combustion or explosions and is fully balanced, the engine is extremely quiet and low in vibration. The

metal housing adds acoustic and thermal insulation.

Reliability of the SolarHeart Engine:

The SolarHeart Engine is designed for a 20,000 hour service interval – 3 years at 80% operating time. Theanticipated lifetime of the engine is over 100,000 operating hours. There is no internal lubrication required

as all bearings are sealed and the moving seals are self-lubricating. Two 3kW units are being evaluated for

reliability on a continuous-operation test stand. One runs continuously, while the other is torn down and

the key components are measured to determine wear rate and estimate component lifetime. One engine

has 5000 hour of run-time (180,000,000 revolutions), while the other has 2800 hours of run-time. Ring life is

expected to be the factor which determines the required service interval.





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Fig 3) 3 kW e SolarHeart® Engine boosting genset output by 5% to 7%.

Other Useful Information about Cool Energy and the SolarHeart® Engine

More about Stirling engines:

Cool Energy has developed the SolarHeart® Engine which is a heat engine based on the Stirling cycle

(invented in the early 1800’s by Robert Stirling) and for which no internal combustion is required. The

Stirling engine is a heat engine that operates by expansion and compression of air or other gas (called the

working fluid), at different temperature levels such that there is a net conversion of heat energy tomechanical work. The SolarHeart Engine uses air as the working fluid, and is driven by relatively low

temperatures (100 °C-300 °C). The mechanical work generated drives a generator built inside the engine

that creates electrical power.

About Cool Energy, Inc.:

Cool Energy is a privately held corporation, based in Boulder, Colorado.

To date, Cool Energy has been backed primarily by angel and venture capital investment and has received

several SBIR grants from the National Science Foundation and the Environmental Protection Agency, as well

as a Department of Energy subcontract and a Colorado Governor’s Energy Office grant. Cool Energy is

currently raising its Series B round of capital for the purposes of beginning volume manufacturing.

For more information about the company, please contact Sam Weaver, CEO at

[email protected] or 303-442-2121.





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20 kWe SolarHeart Engine preliminary specifications:Operating speed: 600 RPM

Engine weight: 5500 lbs

Engine dimensions: 44” dia. x 90” tall

Lifetime: 100,000 hours, with service interval every 20,000 hours

Operating Ambient Temperatures: -40 °C to 80 °C

Output Voltage: up to 500V-dc

Operating parameters: see table below

Hot Side InletTemp, °C

Oil FlowRate, L/min

Hot SideOutletTemp, °C

Input HeatRateRequired, W

RejectionHeat RateRequired, W

Net ElectricalOutput Power, W

Thermal to

ElectricalConversionEfficiency

100 200 92 50493 48999 1414 2.8%

100 300 95 50610 48912 1605 3.2%

100 450 96 50671 48853 1712 3.4%

100 675 98 50662 48806 1721 3.4%

150 200 141 55364 48774 6255 11.3%

150 300 144 55465 48698 6421 11.6%

150 450 146 55518 48646 6513 11.7%

150 675 147 55507 48605 6518 11.7%

200 200 191 59550 48597 10401 17.5%

200 300 194 59640 48532 10546 17.7%

200 450 196 59672 48475 10624 17.8%

200 675 197 59661 48440 10624 17.8%

250 200 241 63226 48503 13982 22.1%

250 300 244 63309 48449 14110 22.3%

250 450 246 63352 48411 14180 22.4%





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250 675 247 63340 48381 14177 22.4%

300 200 290 66539 48512 17121 25.7%

300 300 294 66616 48466 17237 25.9%

300 450 296 66656 48433 17299 26.0%

300 675 297 79418 58321 20010 25.2%

3kW SolarHeart Engine preliminary specifications:

Operating speed: 200-600 RPM

Engine weight: 2000 lbs

Engine dimensions: 36” dia. x 44” long

Lifetime: 70,000 hours with no maintenance

Operating Ambient Temperatures: -40C to 80C

Output Voltage: up to 500V-dc

Operating parameters: see table below

Hot Side

Input

Temp

(°C)

Oil Flow

Rate

(liters/min)

Hot Side

Outlet

Temp

(°C)

Input Heat

Rate

Required (W)

Rejection

Heat Rate

Required

(W)

Electrical

Output

Power

(W-dc)

Thermal to

Electrical

Conversion

Efficiency (%)

100° C 40 91 9085 8419 579 6.4%

100° C 75 96 9105 8412 639 7.0%

100° C 110 97 9077 8444 658 7.2%

100° C 150 98 9023 8501 667 7.3%

150° C 40 141 9959 8451 1288 12.9%

150° C 75 145 9990 8441 1345 13.4%

150° C 110 147 9985 8464 1362 13.6%

150° C 150 148 9963 8508 1370 13.7%

200° C 40 190 10722 8480 1911 17.8%

200° C 75 195 10757 8472 1965 18.3%

200° C 110 197 10757 8493 1981 18.4%

200° C 150 198 10744 8533 1989 18.4%

250° C 40 240 11403 8512 2462 21.6%

250° C 75 245 11438 8506 2512 22.0%

250° C 110 247 11441 8527 2527 22.1%

250° C 150 248 11431 8567 2534 22.1%

300° C 40 290 12022 8551 2954 24.6%

300° C 75 295 12055 8548 3000 24.9%

300° C 110 297 12058 8570 3014 25.0%

300° C 150 298 12050 8609 3020 25.0%

Operating Parameters for Cool Energy SolarHeart® Engine with a 20°C rejection environment.





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The dimensions, drawings, typical illustrations, weights, materials, and details of construction included

herein, while representing the best information available at the time of the issuance of this Proposal, may

vary from that set forth during the development of the final design under terms of contract. Such drawings

as are included in this Proposal are intended only to illustrate the arrangement of equipment and are not to

be construed as defining the extent and scope of the material Cool Energy proposes to furnish.

No part of this document may be reproduced or transmitted in any form or by any means, electronic or

mechanical, without the express written permission of Cool Energy, Inc.

While Cool Energy, Inc. endeavors to ensure that the information in this document is correct and fairly stated,

Cool Energy makes no representation or warranty of any kind in this document and shall in no case be liable

for any errors or omissions or damages, regardless of legal theory, for any use or reliance upon this

information.

Due to continuous product improvement, information is subject to change without notice.

© 2014 Cool Energy, Inc. Cool Energy and SolarHeart are registered trademarks of Cool Energy, Inc. All other

marks are the property of their respective owners.

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