Solar Cogeneration for
Commercial Rooftops
Arun Gupta, PhD
agupta@skyentechnologies.com
Introduction
What is Solar Cogeneration?


Fun fact: Typical photovoltaic (PV) solar panels waste roughly
85% of their energy as heat
Q: Why not capture that heat and use it to heat water?
What is Concentrating Solar?


Using mirrors or lenses to concentrate sunlight
Why? Less PV material, higher thermal efficiency
Applications For Solar Cogen
Commercial & industrial buildings with significant hot water needs
Universities,
Apartments, & Hotels
Food Processing
Industrial Washing
Desalination
Commercial
Cooling & Heating
Hospitals
Solar Cogen w/o Concentration



Bond a standard solar panel on top of a solar water
heater
Problem: really low thermal efficiency
Is it worth the plumbing costs?
Challenge of Concentrating Solar
Tracking increases cost, reduces reliability




Need strong rigid supports
Big motors
Exposed to elements
Wind, dust, moisture
Curved
mirrors
Optics are expensive


Large curved mirrors
Fresnel lenses
Big
Motor
Strong
Supports
A Unique Solution

Proprietary error-tolerant internal tracking system
No heavy steel supports -- just integrated aluminum racking
 No large motors with questionable reliability
 Tracking and optics protected from the elements


Proprietary optics reduce cost
No Fresnel lenses or curved mirrors
 Manufactured with small quantities of low cost materials


Generates more electricity than any other system
Superiority of High Concentration
Skyven uses triple junction III-V PV cells that are…

500x more expensive per cm2 than silicon solar cells
But they produce power with…


2x higher efficiency
800x solar concentration
That’s 1600x more power production at 500x the cost,
or a 3.2x cost advantage
Concentration vs Tracking Cost
None
10
1000
100
CONCENTRATION
TRACKING & OPTICS COST
None
$
(1 axis)
$$
(2 axis)
$$$
(ultra
precision)
Skyven has no external tracking and injection molded optics
The Skyven Cogen System
Rows of stationary mirror panels reflect and
concentrate sunlight onto the back of the previous row
The Skyven Cogen System
Wind deflector
Small lightweight mirrors move
in two axes to track the sun
Co-installed with
traditional PV panels
Protected by stationary
aluminum frame & glass window
Solar receiver optics
Water heating pipe
CPV cells (hidden)
Max Rooftop Power Density
How much power
output can each solar
product get from a
1500m2 rooftop area?
Skyven Cogen
207kW peak electrical
230kW peak thermal
437kW peak total
Traditional PV Alone
150kW peak electrical
Solar Hot Water
270kW peak thermal
Avg. in US for water hot enough for thermal storage
Installed Cost on Electricity
Based on electricity from a 1500m2 system, ignoring hot water
Skyven
Modules
Racking
Inverters & eBOS
Labor
Misc & Soft Costs
Total
Per Watt
$255k
incl. w/ modules
$60k
$40k
$129k
$484k
$2.34/W
Cost data from GTM Research and NREL
Traditional PV
$105k
$42k
$60k
$40k
$129k
$376k
$2.50/W
Installed Cost on Hot Water
Based on system from 1500m2 rooftop
Additional costs
over those in the
electrical cost
analysis
Collectors
Racking
Other Hardware†
Labor
Soft Costs
Total
Per Watt
Skyven
--$92k
$75k
-$167k
$0.73/W
†Heat exchanger, pump, valves, sensors, storage tank, piping, insulation
Solar Hot Water
$270k
$45k
$120k
$225k
$180k
$840k
$3.11/W
Cost data from NREL, SunMaxx, and Heliodyne
Water Heating Cost Comparison
LCOE ($/MMBTU)
40
30
20
10
0
Skyven
CapEx ($/Wt) $0.73
Power|Fuel -LCOE†/MMBTU $11.13
Solar Hot
Water
$3.11
-$25.78
Traditional Heat Pump Natural Gas
Electric
-$0.40
-$0.10/kWh $0.10/kWh $8.13/MMBTU
$41.90
$14.94
$11.72
†Levelized Cost of Energy (LCOE) of 80°C heat over 25 year lifetime with 3% inflation
Electricity and natural gas cost data from US EIA (US national avg. in 2012 in commercial sector)
High Efficiency
Thermal Efficiency @ 80°C
50
20
40
Data from factory datasheets
Cogenra
Cogenra
0
First Solar CdTe
0
Yingli mc-Si
10
Sunpower sc-Si
5
SunDrum
20
Evac'd Tube
10
30
Flat Plate
15
Skyven
% efficient
25
Skyven
% efficient
PV Efficiency
Data from SRCC at 80C above ambient
(hot enough for thermal storage)
Ultra-low Wear & Tear
Stepper Motors

Brushless: Moving parts never touch so immune to wear & tear
Plastic Gears & Bearings



Commonly rated for 5000+ hours of movement
Skyven mirrors move for 0.05s once every 5s, or 1% of the time
5000 hours / 1% = 500k hours = 58 year lifetime
50+ Year Proven Lifetime in the Field


Factory automation, industrial machinery
Aerospace, automotive, and telecom
Ford Shelby Mustang Throttle Body
Inexpensive Materials That Last
Mirrors: talc and carbon
black filled polypropylene
Used in industrial piping
Reflective surface: 3M
Solar Mirror Film
Used in utility scale CSP
Challenges on the Rooftop

Must be light enough for
the roof to support

Must have low height to
avoid eyesores

Must have straightforward
and easy installation
Light Weight
System Weight
Solar Water
Heater
Roof attach only
Chromasun
MCT
Roof attach only
Ultra light
PV
Ballast with roof attach option
Skyven
Ballast with roof attach option
0
Ballast Weight
1
2
3
LBS / SQ FT
4
5
Ease of Installation
Integrated racking unfolds
like legs of a table.
Receivers slide in like a drawer
Wind deflectors snap into
place like a tent cover.
Wires plug together and
pipes screw together
Benefit Summary

Revolutionary system design
 Ultra low cost

Combined heat & power
 High efficiency

Moving parts protected
 High reliability

Lightweight panel
 Rooftop friendly

Integrated racking & plumbing  Installer friendly
Prototype & Technical Validation
Successful electric
and thermal
harvesting
Achieves
temperatures
above 420°C
Gen1 Prototype, completed Nov. 2013
“The detailed technical and economic calculations suggest that
this project can be successful for flat commercial rooftops”
“This project can have a huge impact in reducing the energy
consumption of new and existing buildings”
– The US Dept. of Energy, Office of Science
May 2013
Thank you!
Questions?
Backup Slides
Industry Landscape
Water
Heating
Electric
Power
The Grid
Gas CHP
Solar
CHP
Traditional PV
Natural gas or electric
water heaters, water
heat pumps
Solar
Water Heating
Building Efficiency
Upgrades
Clean
Technology
Solar CHP Competitors
Cogenra
Chromasun Sundrum /
Solimpeks
Skyven
Height above
rooftop
6 ft
5 ft
< 3 ft
3 ft
Heat to
electricity ratio
3:1
∞
2:1
1:1
External motors
reliability risk
External
Internal
None
Internal
No PV
$1.50/W
None
Ease of
installation
Extra cost over a
PV installation†
†How much would it cost above a standard PV installation with equivalent electric output?
INDUSTRIAL
COMMERCIAL
Market Size
TAM: 300GW solar power potential
c
on commercial rooftops
in the US,
800GW globally
TAM: 3200GWth of low temp
(<120C) solar hot water capacity
globally by 2050 for industrial
process heat.
Global Market Size
Commercial: $120 billion
Industrial: $1.7 trillion
Data from NREL, McKinsey, DOE Office of Building Equipment, and IEA
SAM:
15% need
hot water
SAM:
100% need
electricity
Go to Market Strategy

Target direct sales to colleges and universities
Hungry for green image portrayed by renewables
 Larger risk profile for innovative technologies
 Have regular renovations and areas with hot water need


Example of initial traction
Eastfield College in Dallas, TX is ready for a pilot installation
 We have already surveyed a rooftop site and established how
the system will interface with existing building systems

Scale-Up Strategy

Top-tier new construction and renovation companies
General Contractors and Architects
 Building Efficiency Companies
 Solar EPCs (engineering, procurement, construction)


Example of initial traction

The Whiting-Turner Contracting Company (#106 on Forbes’
largest private company list)
Manufacturing Strategy



Key design requirement: System must be entirely
manufacturable with standard equipment
Strategy: Contract manufacture, assemble, and ship
Benefits:
Minimizes up-front capital requirements
 Allows for supply-chain competition


In early discussion with manufacturing consulting firm
with over 200 years of combined experience
Standard injection-molding machine available globally
Founding Team
Arun Gupta, PhD
Founder & CEO
Expert in electrical/mechanical/optical system design. Used
this expertise to found a business that has raised over $30M
and is expected to generate $100M+ revenue in 2015.
Alvin Hathaway Jr., JD, MBA
Business Operations & Intellectual Property
Expert in supply chain management and licensed IP attorney.
Experience includes managing a complex international
supply chain for a $400M+ business.
Advisors & Partners
Bryan Russett
Solar Industry Advisor
Broad experience in the solar industry from Schneider Electric,
Solar Design Associates, and several start ups. Includes design
and installation of PV systems from 2kW to 10MW.
Michael Moussa
Mechanical Engineering Consultant
Mechanical design and manufacturing expertise for extreme
reliability parts used in bridges. Owns a rapid prototyping
company.
$ millions
Revenue Forecast
900
800
700
600
500
400
300
200
100
0
2014 2015 2016 2017 2018 2019 2020
Product Launch
Break Even
Early adoption
Main stream
adoption
Development Plan & Funding Needs
Development Milestone
Completion Funding
Date
Required
1st gen prototype generates real-world power &
heat
Nov 2013
--
Integrate system electronics
Mar 2014
$300k
Complete final design for racking and frame
May 2014
Long-term outdoor performance prototype ready
for test
Aug 2014
3rd party validation of long-term outdoor
performance
Mar 2015
System is ready for production
Mar 2015
Safety certifications obtained. Initial orders placed.
Sep 2015
Production begins
Oct 2015
$2M
* Funding will support employee wages, material costs, and 3rd party laboratory fees
Status Summary (Dec 2013)

Completed:
Fully functional prototype
 Full patent filed


Currently seeking:
Series A funding to
manufacture product
 Strategic partners


First gen prototype panel
Future milestones:
2nd gen form-fit-function prototype: expected mid 2014
 Manufacturing-ready by mid 2015

Risk Reduction
Just as Tesla adapted laptop batteries to power cars
Skyven is adapting projector technology for solar energy
Projector Technology
Projector
DLP Chip
Skyven
Mirror Panel
Light Source
Optics
Triple Junction PV Cell
Skyven’s optics work similar to a projector running backwards.
Commercial HVAC Decision Tree
From DOE Office of Building Equipment
High Reliability
Materials
That Last
Slow Moving
Internal Parts
High Reliability
PV Cells and Motors
Adapted from
Space Technology
All parts sealed in
glass / aluminum
enclosure
Green Buildings at the Right Cost

Rooftop systems technology that combines solar
power with solar water heating

Drastic reduction in levelized cost
 Water
heating: Lower than any other method,
including burning natural gas
 Power: Matches the best that PV has to offer
Extreme Efficiency
Cost Savings
Our System




Rows of flat, south-facing panels tilted at 45°
Each panel contains hundreds of coaster-sized flat mirrors
Mirrors track the sun in two axes, reflecting sunlight into
receivers mounted on the back of the preceding row
All moving parts protected inside a glass and aluminum panel
housing. Panels themselves are stationary.
Receivers
Panel
Racking & Wind Deflector