CONVENTIONAL, PV-ONLY AND/OR HYBRID PV/SOLAR THERMAL SYSTEMS
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PHOTOVOLTAIC-ONLY SOLAR PANELS
As an alternative to Hybrid PV/solar thermal solar panels we can install PV-Only electrical panels using conventional aluminum racks as is shown below in a 2007 installation on the residence of Gerald Falbel in Stamford Connecticut. This type of system has an installed price 10% less than the typical quote shown for the Hybrid system below.
12 PV PANELS INSTALLED IN 2007 ON
G. FALBEL RESIDENCE
IN GENERAL OUR INSTALLED PV-ONLY SYSTEMS PRICES ARE 10% LOWER THAN ANY COMPETING QUOTE. PLEASE INQUIRE BY CALLING US AT 203-357-0626
ROOF INTEGRATED HYBRID SYSTEMS
THIS SYSTEEM PROVIDES PV ELECRICITY AND HOT WATER HEATING WITH NO MONEY DOWN, POSITIVE CASH FLOW IMMEDIATELY, LESS THAN 4 YEAR PAYBACK, AESTHETIC APPEARANCE LIKE A SKYLIGHT BECOMES A 50 YEAR PERMANENT ROOF COMBINED SOLAR EFFICIENCY > 60%
FIGURE 1 PV/Thermal hybrid panel
FIGURE 1A
FIGURE 1B PHOTO OF PROTOTYPE HYBRID PANEL
FIGURE 2 SETUP FOR RURAL HYBRID SYSTEM OPERATING IN BRIDGEPORT CT (ACHIEVED 120°F AFTER ONLY 2 HOURS)
ROOF-INTEGRATED HYBRID SYSTEM DESCRIPTION
Photovoltaic electric solar panels (hybrid PV/ solar thermal 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 5, 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 2, 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 60°F above the outside ambient temperature for summer solar insolation. When the rear surface of the solar panel exceeds 60°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 of 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 130°F typical panel temperature with only rear surface air cooling, when mounted in conventional racks, and 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, the solar electrical energy generated during the warm months is improved by up to 10% 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 $2.50 per square foot, or approximately $60 per 300 watt PV panel, which is paid for by the savings generated by the elimination of the conventional PV panel aluminum extruded 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.
A final advantage of this construction is that the rubber tube mat mounted behind the glass solar panel may provide additional protection against hail damage by its cushioning effect.
FIGURE 1 CROSS-SECTION OF HYBRID PV/SOLAR THERMAL INSTALLATION
FIGURE 2 TYPICAL EPDM RUBBER 5” WIDE TUBE MAT CURRENTLY USED IN OUR SOLAR SWIMMING POOL HEATERS
FIGURE 3A PHOTO OF HEAT EXCHANGER INSTALLATION
FIGURE 4 HYUNDAI SOLAR PANEL 300 WATTS UL AND CEC APPROVED
FIGURE 5 TWENTY FOUR 300 WATT PANELS (UL AND CEC CERTIFIED)
TYPICAL HYBRID SYSTEM PRICE QUOTATION
DESCRIPTION
TWENTY FOUR, 300 WATT HYUNDAI PHOTOVOLTAIC PANELS, WITH EPDM RUBBER TUBE MATS PRESSED AGAINST THE REAR OF PANELS, FLUSH MOUNTED TO SOUTH ROOF, AS IS SHOWN IN FIGURE 5 ABOVE.
THE RUBBER TUBE MAT MANIFOLDS ARE CONNECTED TO A STAINLESS STEEL HEAT EXCHANGER, ATTACHED TO EXISTING SOLAR TANK IN BASEMENT, 60°F THERMAL SWITCH ENERGIZES THE PUMPS TO RUN ANTI-FREEZE THROUGH THE RUBBER TUBE MATS THUS COOLING PANELS, AND PRE-HEATING DOMESTIC HOT WATER IN EXISTING TANK.
SYSTEM IS WARRANTED TO PREVENT SOLAR PANELS TEMPERATURES FROM EXCEEDING 140°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.
FOR 100% FINANCING Please call: Mr. Robert Baylis Loan Advisor
401-248-7358 or mailto:rbaylis@admiralsbank.com
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 $20,000 loan for which your net cost after the federal tax rebate is only $14,000, you will be paying down the loan for the remainder of 2016 at an interest rate applicable to the principal of $14,000, but when you get your $6,000 rebate in April 2018, you can use it to pay down the principal to $14,000. The Connecticut rebate is paid to the CEFIA registered solar installer and is subtracted from the total price.
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: $20,000-
NET COST AFTER 30% FED INCOME TAX SOLAR REBATE $14,000.00
NET COST AFTER CONNECTICUT SOLAR REBATE
OF $0.40/WATT OF SOLAR POWER FOR 7,2 00 WATTS $2,880.00
NET COST $11,120.00
ELECTRICAL ENERGY COST SAVINGS FOR A 24 PANEL, 300 WATT/PANEL (7.200 WATT) INSTALLATION= $
- ELECTRICAL POWER COLLECTION AT NOON WITH 1,000 WATT/m2 SOLAR IRRADIANCE = 24 X 300 WATTS/PANEL
= 7.2 KWATTS X 5 EFFECTIVE HOURS/DAY
= 36 KWATT-HRS/SUNNY DAY X $0.25/KWATT-HR. = $9.00 PER SUNNY DAY x 200 SUNNY DAYS PER YEAR IN CONNECTICUT. = $1,800-/YEAR ELECTRICITY COST SAVINGS + $180- SOLAR ELECTRICITY GENERATED DURING CLOUDY DAYS) = $1,980-/YEAR
FOR OIL HEATED HOT WATER,
- THERMAL ENERGY COST SAVINGS (NOT APPLICABLE IN CONVENTIONAL PHOTOVOLTAIC-ONLY INSTALLATION)
60°F TEMPERATURE RISE IN 120 GALLON STORAGE TANK PER SUNNY DAY IN THE SUMMER
= 120 GAL. X 7.41 LBS./GALLON X 60°F X 1 BTU/LB./DEG.F
= 53,352 BTU/SUNNY DAY = 0.53 GALLON OF OIL
= $1.33 SAVINGS PER DAY AT $2.50/GALLON OIL COST
= $1.33 X 200 SUNNY DAYS/YEAR = $267/YEAR THERMAL SAVINGS FOR OIL HEATED WATER
FOR ELECTRICALLY HEATED HOT WATER,
53,352/3,423 watts/BTU
= 15.6 kwatt hours/sunny day x $.25/kilowatt hour = $3.90/sunny day
For 200 sunny days/year electricity savings = $779-/year
PAYBACK PERIOD ASSUMING NO OIL RATE PRICE INCREASES FOR CONNECTICUT
$11,120-/($1,980 + $267)= 4.9 YEARS
= 20.2% RETURN ON YOUR INVESTMENT, TAX FREE!!
PAYBACK PERIOD FOR ELECTRCALLY HEATED DHW
$11,120-/($1,980+$779-) = 4.03 YEARS
= 24.8% RETURN ON INVESTMENT TAX FREE!!