Page 69 - Green Builder Homeowner's Handbook 2016

Exteriors / Roofing / Structure / Insulation / IAQ / Windows / Heating / Lighting / Appliances / Faucets & Fixtures / Finishes / Cabinets & Tops / Alternative Energy
on the savings.
Solar leasing programs are not available in every state (or in every
region of a given state); however, the largest providers are continu-
ally expanding their territories. Companies that offer solar leases are
SolarCity, SunPower, Sunrun, Sungevity, Real Goods Solar and NRG
Home Solar (www.nrghomesolar.com).
SOLAR HOT WATER
Smart Storage
The availability of extremely durable hot water storage tanks—
which in some cases also serve as water heaters—has made solar
hot water collection even more viable. Many tanks now include a
separate closed loop of a freeze-resistant liquid. That extra loop is
specifically for solar hot water—so that when the sun is shining,
the solar panels on the roof heat the clean water in the tank.
But when the sun is not sufficient (or you have teenagers using up
the “free” hot water) an external boiler or heating system built into
the tank kicks on to make up the difference.
One of the great advantages of a solar hot water system is the
relatively rapid payback. In other words, if you install this year, it
may pay for itself in less than three years, especially once you figure
in the tax credits and rebates available.
COGENERATION
Waste Not
Cogeneration has been common at large factories for decades. It’s
basically a way of squeezing more work out of fossil fuels. Also
known as combined heat and power (CHP) generation systems, these
mechanical wonders put the waste heat generated by a home furnace
or boiler to work making electricity. By some estimates, they achieve
90 percent efficiency, compared with 30 to 40 percent from your local
power station. If you’re already replacing or installing a new boiler
or furnace, why not take it to another level and try cogeneration?
RESILIENCE
Back-Up Plan
A renewable energy system can be part of a strategy for keeping
your home powered up during storms and power outages. Grid-tied
solar PV systems aren’t available when the grid powers down, so
it’s necessary to have a back-up plan. While gas- or propane-fired
generators are a good conventional source of back-up power, other
options are becoming available. Some inverter manufacturers are
starting to build in a limited amount of storage into their products.
Stand-alone solar panels can be used to power specific appliances.
SMA Sunny Boy TL-US
Inverter with Secure
Power Supply
The Sunny Boy TL-US can provide up
to 1,500 watts of daytime power to a
dedicated power outlet during prolonged
power outages, without using batteries.
This transformerless inverter is 97.6
percent efficient and is able to accept a
wide input voltage range.
www.sma-america.com
www.greenbuildermedia.com
Solar Roof Area
There are a number of different things you
need to know before calculating the roof area
required for your solar panel installation:
1. The size of the system.
2. The type and dimensions of the solar panels.
(You can get these from the solar panel datasheet.)
3. The spacing between solar panels.
4. The orientation of the panels.
Once you’ve gathered this information,
here’s how to calculate the area required:
Size of the system (watts) ÷ size of the solar panel (watts)
= number of panels required.
Example: 5-kW system ÷ 250 W = 20 panels
Each panel measures 1,680 mm x 996 mm,
or 1.68 m x 0.996 m = 1.67 m2
Total Area = 20 panels x 1.67 m2 = 33.40 m2
A little bit of space will also be needed between each panel
for fixing the panels to the racks—this will depend on what
type of racking system is used.
Orientation. If you don’t have enough roof space on a single
roof face, consider splitting your system into two different
orientations. The best orientation for panels (in the Northern
Hemisphere) is south. East and west are slightly less efficient
(around 9 percent less). If you split your panels between your
south and west roofs evenly, you would only lose around
4.5 percent of your overall system capacity.
Battery banks have long been a staple of off-grid systems, but home
batteries for grid-tied systems are just around the corner. Electric
vehicle batteries paired with the right EV charger are another up-and-
coming back-up power source. In this way, different power sources
become part of a dynamic system that not only makes your home
more resilient, but turns it into a dynamic participant in the grid
rather than just an end user. GB
Bosch eBike Systems
Available for the North
American market in 2016,
Bosch’s eBike system consists
of an electrified drive unit,
battery pack, computerized
control panel and charger.
An eBike can be part of an
overall strategy for reducing
emissions and building resilience, especially if you charge with solar
power.” http://bit.ly/1FMbBpa
The Homeowner’s Handbook 2016 GREEN BUILDER 67