Home Energy

1
Home Energy

• Bruce L. Hesher
• Brevard Community College
• Engineering Technology
• Energy Systems
• 433-5779

2
Permitting

• 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.

3
Scope

• This presentation describes a renewable energy
  approach to maintaining a swimming pool without
  buying electricity. By targeting a high
  electricity cost item like swimming pool, short
  paybacks can be seen.
• Additionally with modification the system
  described in the presentation could provide power
  to critical loads during extended power outages
  such as those after a hurricane.
• The example in this presentation uses solar
  panels and passive water 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 circulate, filter and heat a swimming
  pool.
• A swimming pool can be the single largest
  power consumer in the home.

4
Energy Survey
The first step to either reducing your energy
bill or producing your own power is to determine
where your energy consumption occurs. Most
utility companies, including FPL, have on-line
tools to help you identify where your electricity
dollars go.
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 50/month,
it was the single largest slice of the pie even
larger than the air conditioner.
Contact your local permitting office to
determine what is required. 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 permit in a commercial
setting, you must be properly licensed!
5
Target Power Hungry Items

• 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 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.
Safety note 96V at 3.5 Amps can be dangerous.
Cover the panels with cardboard or black plastic
while assembling or working on the system !
6
Wiring and Electrical Conduit

• 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 Electrical Code
(NEC). The nameplate on the back of the
modules sates the short circuit current (Isc) as
4A. As per section 690 of the NEC, the current
must be de-rated for 125 of the maximum Isc and
for roof temperatures. 90C rated wire on a roof
at temps up to 50C must be de-rated to 82 of
its ampacity as per table 310.16 of the 2008 NEC.
So
(4A 1.25) / 0.82 6.1A Consult the American
Wire Gauge (AWG) table for the appropriate wire
size. Use stranded wire so that you can feed it
through the conduit.
Use metal or UV rated PVC conduit !
7
Module Placement

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

8
Controller

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

Lorentz model PS600
Safety note Make sure the switch on the
controller box is turned off while assembling.
9
Filter 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.
10
Pump

• 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.
11
Heating 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.
12
Financial Review
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!
13
Related 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 Floridas 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.