Hybridsolaroof Combined PV solar thermal system with 4 year payback

OPTICAL ENERGY TECHNOLOGIES INC. www.opticalenergy.com
472 WESTOVER ROAD, STAMFORD CT. 06902
TEL: 203-357-0626 FAX: 203-348-8761 email: gfalbel@optonline.net
PROPRIETARY DESIGN INFORMATION
HYBRID-PHOTOVOLTAIC/THERMAL
SOLAROOF™
Photovoltaic electric solar panels can also be built into the roof in the
SOLAROOF configuration to provide an aesthetic appearance, save roofing
costs, and provide a 50 year roof while eliminating the possibility of leaks at
the mounting points applicable to standard, rack-mounted panel installations.
The construction of PHOTOVOLTAIC SOLAROOF™ is shown in Figure 1,
and is lower cost than conventional solar panel installations, since mounting
brackets for these panels are eliminated.
This hybrid photovoltaic + solar thermal configuration is shown in Figure 1, in
which an EPDM rubber tubing mat (Figure 2) is pressed to the rear surface of the
photovoltaic panel glass. The measured typical increase in the temperature of
this rear surface is more than 50°F above the outsi de ambient temperature for
summer solar insolation. When the rear surface of the solar panel exceeds 80°F,
tank water temperature, anti-freeze is pumped through this mat, transferring its
collected thermal energy to the domestic hot water in the storage tank to provide
solar thermal domestic hot water pre-heating, thus providing additional solar
energy harvesting, which further reduces the payback period. For typical water
heaters, the water temperature starts at the 54°F o f incoming cold water at
sunrise. Therefore, the anti-freeze in the heat exchanger cools the photovoltaic
panel to near its rated electrical output at 25°C ( 77°F) thus improving the
electrical output efficiency relative to that of convention rack mounted PV panel
installations. This heat collection also cools the temperature of the photovoltaic
solar panel during the warm months, (which are also the months in which the
maximum photovoltaic energy is generated). Depending upon the size of the
domestic hot water tank and the number of PV panels, the temperature of the
panel will never reach the 120°F typical panel temp erature with only rear surface
air cooling, when mounted in conventional racks. In our system the panels will
have an average temperature during the solar day less than 100°F. For solar
swimming pool heating, the pool water is circulated directly through the rubber
tube mats, and the panel temperatures are maintained throughout the day at less
than 85 °F.
Since photovoltaic panel electrical output efficiency degrades by approximately
0.4% per degree Celsius above 25°C, (*77°F) the sol ar electrical energy
generated during the warm months is improved by up to 15% over conventionally
mounted PV panels, while also pre-heating the domestic hot water, (or the

swimming pool) which provides further savings of fuel or electricity costs during
this period.
In the winter, during a snow storm, by manually turning on the solar heating
pump, this system can also melt off the snow cover of the panels to restore full
photovoltaic output.
The material cost of installing these EPDM rubber mats is less than $2.00 per
square foot, or approximately $30 per 300 watt PV panel, which is paid for by the
savings generated by the elimination of the conventional PV panel mounting
racks.
In view of the above discussion, it can be concluded that the incorporation of this
hybrid solar system generates a significant improvement in the total energy
output of a conventional PV panel system, and significantly reduces its payback
period.
EPDM RUBBER TUBING MAT STRIPS PRESSED AGAINST
REAR SOLAR PANEL GLASS CONDUCTS HEAT ENERGY
TO DOMESTIC HOT WATER TANK, AND IMPROVES
PHOTOELECTRIC OUTPUT EFFICIENCY
SOLAR PANEL REAR GLASS
SOLAR CELL
ROOF SHEATHING
ROOF
SHINGLES
PVC MANIFOLD
A
A
PROPRIETARY DESIGN
SEALING SCREWS TEN, 380 WATT SUNPREME
FRAMELESS SOLAR PANELS
FIGURE 1 LAYOUT OF HYBRID PV/THERMAL SOLAROOF
INSTALLATION

FIGURE 2 TYPICAL EPDM RUBBER 5” WIDE TUBE MAT
CURRENTLY USED IN OVER TEN OF OUR SOLAR SWIMMING
POOL HEATERS

AUTO. AIR
VENT
TO HOUSE
FAUCETS
EXTROL
EXPANSION
TANK 1/25 HP. PUMP
PRESURE
RELIEF VALVE
(MOVED)
PRESSURE
GAUGE
COLD WATER
SUPPLY
EXTERNAL
STAINLESS
STEELHEAT
EXCHANGER
FOUR
FRAMELESS
SUNPREME
PHOTOVOLTAIC
PANELS
THERMAL
PUMP
CONTROLLER
ANTI-FREEZE
FLOW
RUBBER TUBE
MATS ON
BACK
OF PANELS
120 GALLON
ELECTRIC
W ATER
HEATER TANK
FIGURE 3 HYBRID PV/THERMAL BLOCK DIAGRAM

FIGURE 4 SUNPREME FRAMELESS PANEL DESCRIPTION

TYPICAL HYBRID SYSTEM PRICE QUOTATION
DESCRIPTION
TEN, 330 WATT SUNPREME PHOTOVOLTAIC PANELS, WITH EPDM
RUBBER TUBE MATS PRESSED AGAINST THE REAR OF PANELS, FLUSH
MOUNTED TO SOUTH ROOF, AS IS SHOWN IN THE ATTACHED DRAWING.
A REFLECTIVE FOIL IS MOUNTED BETWEEN THE RUBBER TUBE MATS
AND THE REAR GLASS OF THE PV PANEL. THIS INCREASES THE
OUTPUT OF THE PANEL TO 380 WATTS.
AS IS SHOWN IN FIGURE 3, THE RUBBER TUBE MAT MANIFOLDS ARE
CONNECTED TO A STAINLESS STEEL HEAT EXCHANGER, ATTACHED TO
THE EXISTING SOLAR TANK IN THE BASEMENT, A 60°F THE RMAL
SWITCH ENERGIZES THE PUMPS TO RUN ANTI-FREEZE THROUGH THE
RUBBER TUBE MATS THUS COOLING PANELS, AND PRE-HEATING
DOMESTIC HOT WATER IN THE EXISTING HOT WATER HEATER TANK.
THE SYSTEM IS WARRANTED TO PREVENT SOLAR PANEL
TEMPERATURES FROM EXCEEDING 120°F.
NO CASH DOWN FINANCING FOR SOLAROOFTM
The following summarizes the no cash down financing of our SOLAROOFTM
Hybrid PV/solar thermal systems for either PV + domestic hot water heating or
PV + solar swimming pool heating.
In both cases, the 30% Federal income tax rebate applies.
Note: For solar swimming pool heating alone, the 30% federal tax rebate
does not apply, but with the inclusion of PV panels, the tax rebate is
applicable.
Please also note that for a $10,000 loan for which your net cost after rebate is
only $7,000, you will be paying down the loan for the remainder of 2014 at an
interest rate applicable to a principal of $7,000, but when you get your $3,000
rebate in April 2015, you can use it to pay down the principal to $7,000.
With the 3.5 year payback shown in the following calculation, you should have
positive cash flow for a 120 month loan immediately after the installation!

TOTAL INSTALLED PRICE: $10,000-
NET COST AFTER 30% FED INCOME TAX SOLAR REBATE
(CONNECTICUT) $7,000.00
NET COST IN NY STATE, AFTER 30% FED INCOME TAX SOLAR REBATE
AND NY STATE 25% REBATE $5,250.00
NET COST IN CONNECTICUT, AFTER 30% FED INCOME TAX SOLAR
REBATE AND CONNECTICUT $1,520- REBATE $5,480.00
ELECTRICAL ENERGY COST SAVINGS FOR AN
INSTALLATION USING TEN, 380 WATT SOLAR PANELS
(3.8 KWATTS):
1. ELECTRICAL POWER COLLECTION AT NOON WITH 1,000
WATT/m2
SOLAR IRRADIANCE = 10 X 380 WATTS/PANEL
= 3.8 KWATT-HR X 6 EFFECTIVE HOURS/DAY
= 22.8 KWATT-HRS/SUNNY DAY X $0.25/KWATT-HR. = $5.70 PER
SUNNY DAY X 200 SUNNY DAYS PER YEAR IN CT. = $1,140/YEAR
ELECTRICITY COST SAVINGS
2. THERMAL ENERGY COST SAVINGS (NOT APPLICABLE IN
CONVENTIONAL PHOTOVOLTAIC-ONLY INSTALLATION)
50°F TEMPERATURE RISE IN 120 GALLON STORAGE TANK PE R
SUNNY DAY IN THE SUMMER
= 120 GAL. X 8.34 LBS./GALLON X 50°F X 1 BTU/LB./DE G.F
= 50,040 BTU/SUNNY DAY = 0.50 GALLON OF OIL
= $2.00 SAVINGS PER DAY AT $4.00/GALLON OIL COST
= $2.00 X 200 SUNNY DAYS/YEAR = $400/YEAR THERMAL SAVINGS

PAYBACK PERIOD ASSUMING NO OIL OR ELECTRIC RATE PRICE
INCREASES FOR CONNECTICUT
$1,140 + $400 = $1,540/YEAR
$5,480-/$1,540 = 3.56 YEARS = 43 MONTHS
= 28% RETURN ON YOUR INVESTMENT, TAX FREE!!
PAYBACK PERIOD ASSUMING NO OIL OR ELECTRIC RATE COST
INCREASES FOR NY STATE
$5,250/$1,540 = 2.9 YEARS
=34% RETURN ON YOUR INVESTMENT TAX FREE!!

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