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Bruce L. HesherBruce L. Hesher

Brevard Community CollegeBrevard Community College

EEngineering ngineering TTechnologyechnology

Energy SystemsEnergy Systems

433-5779433-5779

PermittingPermitting

Before doing any electrical or roof work consult your local Authority Having Jurisdiction (AHJ) to determine the permitting requirements. The AHJ is usually the permitting office or municipal building department.

Scope

This presentation describes a renewable energy approach to This presentation describes a renewable energy approach to maintaining a swimming pool without buying electricity. By targeting a maintaining a swimming pool without buying electricity. By targeting a high electricity cost item like swimming pool, short paybacks can be high electricity cost item like swimming pool, short paybacks can be seen.seen.

Additionally with modification the system described in the presentation Additionally with modification the system described in the presentation could provide power to critical loads during extended power outages could provide power to critical loads during extended power outages such as those after a hurricane.such as those after a hurricane.

The example in this presentation uses solar panels and passive water The example in this presentation uses solar panels and passive water heating techniques that can meet all the needs of an in-ground heating techniques that can meet all the needs of an in-ground swimming pool. It was built in 2005. Solar power can be used to swimming pool. It was built in 2005. Solar power can be used to circulate, filter and heat a swimming pool.circulate, filter and heat a swimming pool.

A swimming pool can be the single largest power consumer in the A swimming pool can be the single largest power consumer in the home. home.

Energy SurveyEnergy Survey

The first step to either reducing your energy bill or producing your The first step to either reducing your energy bill or producing your own power is to determine where your energy consumption occurs. own power is to determine where your energy consumption occurs. Most utility companies, including FPL, have on-line tools to help you Most utility companies, including FPL, have on-line tools to help you identify where your electricity dollars go.identify where your electricity dollars go.

An energy survey of my home showed that 27% of my electricity bill An energy survey of my home showed that 27% of my electricity bill was going to power my swimming pool pump! At 27%, or about was going to power my swimming pool pump! At 27%, or about $50/month, it was the single largest slice of the pie even larger than $50/month, it was the single largest slice of the pie even larger than the air conditioner.the air conditioner.

Contact your local permitting office to determine what is required. Contact your local permitting office to determine what is required. As a home owner you can install PV and/or solar pool heating As a home owner you can install PV and/or solar pool heating equipment on your own home but, it must pass inspection. To pull a equipment on your own home but, it must pass inspection. To pull a permit in a commercial setting, you must be properly licensed!permit in a commercial setting, you must be properly licensed!

Target Power Hungry ItemsTarget Power Hungry Items

Two 170W 48V DC modules in series provide 340W at 96V and 3.54Amps.Two 170W 48V DC modules in series provide 340W at 96V and 3.54Amps.

Aluminum mounting rails are mounted to the roof using 3/8” lag bolts that go Aluminum mounting rails are mounted to the roof using 3/8” lag bolts that go into the trusses. The panels are bolted to the rails using 7/16” bolts. The into the trusses. The panels are bolted to the rails using 7/16” bolts. The panels can easily be removed in order to ride out a storm in the garage. panels can easily be removed in order to ride out a storm in the garage.

Safety noteSafety note: 96V at 3.5 Amps : 96V at 3.5 Amps can be dangerous. Cover the can be dangerous. Cover the panels with cardboard or black panels with cardboard or black plastic while assembling or plastic while assembling or working on the system !working on the system !

Wiring and Electrical ConduitWiring and Electrical Conduit Three wires are needed: positive and negative from the modules and a ground wire.Three wires are needed: positive and negative from the modules and a ground wire.

The gauge of the wire must meet the requirements of the National The gauge of the wire must meet the requirements of the National Electrical Code (NEC). The nameplate on the back of the modules sates Electrical Code (NEC). The nameplate on the back of the modules sates the short circuit current (Isc) as the short circuit current (Isc) as 4A4A. As per section 690 of the NEC, the . As per section 690 of the NEC, the current must be de-rated for current must be de-rated for 125%125% of the maximum Isc of the maximum Isc andand for roof for roof temperatures. 90°C rated wire on a roof at temps up to 50°C must be de-temperatures. 90°C rated wire on a roof at temps up to 50°C must be de-rated to rated to 82%82% of its ampacity as per table 310.16 of the 2008 NEC. So: of its ampacity as per table 310.16 of the 2008 NEC. So:

(4A *1.25) / 0.82 = 6.1A(4A *1.25) / 0.82 = 6.1A

Consult the American Wire Gauge (AWG) table for the appropriate wire Consult the American Wire Gauge (AWG) table for the appropriate wire size. Use stranded wire so that you can feed it through the conduit. size. Use stranded wire so that you can feed it through the conduit.

Use metal or UV rated PVC conduit !Use metal or UV rated PVC conduit !

Module PlacementModule Placement

Locate the modules on a south sloping roof at a tilt angle Locate the modules on a south sloping roof at a tilt angle close to the latitude.close to the latitude.

Controller Controller Electricity from the panels goes to a controller that interfaces between the power source (modules) and the load (pump).

Safety note: Make sure the switch on the controller box is turned off while assembling.

Lorentz model PS600

Filter & PlumbingFilter & Plumbing

Size the plumbing to the largest standard size that is practical in order to reduce backpressure and move more water.

Ground wire from panels runs inside conduit to chassis of controller then down to pump and ground rod driven into water table.

Valves in the return line to the pool are used to divert some of the water through a passive solar collector in order to warm the water.

PumpPump

• A continuous ground from the panels to the controller to the pump and to ground is needed.

6’ Copper ground rod with wire to both pump and controller.

Heating the PoolHeating the Pool

It takes a lot of energy to raise the temperature of water! Passive solar heating that does not involve any energy storage or conversion is desirable.

A solar blanket that prevents evaporative heat loss by the pool and/or a solar collector on the return line to the pool are good options.

Financial ReviewFinancial ReviewCost Breakdown

$1,600.00

$700.00

$600.00

$200.00

$150.00

$150.00

panels

Controller

pump

filter

plumbing

wire & conduit

Cost breakdown

panels $1,600.00 2 - 170W at $800 each

Controller $700.00 Lorentz model PS600

DC Pump $600.00 Speck Pumps

Filter $200.00 Hayward

plumbing 2" PVC $150.00 Home Depot

wire & conduit $150.00 Home Depot

$3,400.00

tax rebate $1,200.00

cost after rebate $2,200.00

monthly savings $50.00

payback months 44

The total cost of this system in 2005 was $3,400. This yields a payback of 68 months, 44 after incentives. The system has a life expectancy of over 30 years on the panels and 10-12 years on the controller and pump.

Reduced equipment costs since 2005 make the payback much better!

Related WebsitesRelated Websites

American Council for an Energy-Efficient Economy (ACEEE), www.aceee.org

www.fpl.com Florida Power and Light. Use to determine where your energy dollars are going.

www.fsec.ucf.edu/en/ Florida Solar Energy Center . The state of Florida’s energy research institute,

www.brevardcc.edu Brevard Community College

www.dsireusa.org This is the website that details active rebate and tax incentive programs for alternative energy.