Page 63 - The Homeowner's Handbook 2017

Exteriors / Roofing / Structure / Insulation / IAQ / Windows & Doors / Heating & Cooling / Lighting / Appliances / Plumbing / Finishes / Cabinets & Tops / Alternative Energy

on the savings.
Solar leasing programs are not available in every state (or in every Solar Roof Area
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 There are a number of different things you
Home Solar (www.nrghomesolar.com). need to know before calculating the roof area

required for your solar panel installation:
SOLAR HOT WATER
Smart Storage 1. The size of the system.
The availability of extremely durable hot water storage tanks— 2. The type and dimensions of the solar panels.
which in some cases also serve as water heaters—has made solar (You can get these from the solar panel datasheet.)
hot water collection even more viable. Many tanks now include a 3. The spacing between solar panels.
separate closed loop of a freeze-resistant liquid. That extra loop is 4. The orientation of the panels.
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. Once you’ve gathered this information,
But when the sun is not sufficient (or you have teenagers using up here’s how to calculate the area required:
the “free” hot water) an external boiler or heating system built into Size of the system (watts) ÷ size of the solar panel (watts)
the tank kicks on to make up the difference. = number of panels required.
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 Example: 5-kW system ÷ 250 W = 20 panels
may pay for itself in less than three years, especially once you figure
in the tax credits and rebates available. Each panel measures 1,680 mm x 996 mm,
or 1.68 m x 0.996 m = 1.67 m 2
COGENERATION Total Area = 20 panels x 1.67 m = 33.40 m 2
2
Waste Not
Cogeneration has been common at large factories for decades. It’s A little bit of space will also be needed between each panel
basically a way of squeezing more work out of fossil fuels. Also for fixing the panels to the racks—this will depend on what
known as combined heat and power (CHP) generation systems, these type of racking system is used.
mechanical wonders put the waste heat generated by a home furnace Orientation. If you don’t have enough roof space on a single
or boiler to work making electricity. By some estimates, they achieve roof face, consider splitting your system into two different
90 percent efficiency, compared with 30 to 40 percent from your local orientations. The best orientation for panels (in the Northern
power station. If you’re already replacing or installing a new boiler Hemisphere) is south. East and west are slightly less efficient
or furnace, why not take it to another level and try cogeneration? (around 9 percent less). If you split your panels between your
south and west roofs evenly, you would only lose around
RESILIENCE 4.5 percent of your overall system capacity.
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 Battery banks have long been a staple of off-grid systems, but home
solar PV systems aren’t available when the grid powers down, so batteries for grid-tied systems are just around the corner. Electric
it’s necessary to have a back-up plan. While gas- or propane-fired vehicle batteries paired with the right EV charger are another up-and-
generators are a good conventional source of back-up power, other coming back-up power source. In this way, different power sources
options are becoming available. Some inverter manufacturers are become part of a dynamic system that not only makes your home
starting to build in a limited amount of storage into their products. more resilient, but turns it into a dynamic participant in the grid
Stand-alone solar panels can be used to power specific appliances. rather than just an end user. GB

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JinkoSolar Steel Roof Mount Available for the North
A simple, fast and cost effective system American market in 2016,
allows you to mount PV modules on tin Bosch’s eBike system consists
and other color corrugated steel roofs. of an electrified drive unit,
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design reduce installation time and cost. overall strategy for reducing
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