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THE INSIDE SCOOP
GREEN BUILDER RECOMMENDS
In most cases, a solar hot water system is a good first step toward solar independence. Next, before installing a wind turbine or PV system, do an energy audit of all electrical items in your house and make sure you’re living efficiently. Until battery technology improves, we recommend grid-tied PV systems as a supplement to your normal utility service. Remember that wind turbines won’t make sense in every region, but PV is almost always feasible. Be realistic about how much power a turbine can generate at your location.


 


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% efficiency, compared with 30%–40% from your local power station. That means you’re creating energy that’s a lot less polluting than the stuff coming in on the wire from your street. If you’re replacing or installing a new boiler or furnace, why not take it to another level?


GLOSSARY OF TERMS
KNOW THE LINGO
> Inverter
Device that converts direct current (DC) electricity into alternating current (AC), the type of power most commonly used by U.S. appliances and light fixtures.


> Grid-Tied
Electricity produced on site (from photovoltaic panels, wind turbines, etc.) is fed directly into local power lines, rather than being stored in batteries.


> Cogeneration
Production of electricity from heat that would otherwise be wasted, such as hot flue gases produced by a gas-powered furnace or boiler.


> Wind Maps
Useful for siting (and evaluating the viability of) wind turbines, wind maps show how much wind can be expected in a geographic region or specific site.


> Building Integrated Photovoltaics (BIPV)
Electricity generating solar panels that have been designed to resemble various familiar types of roofing.


> Standby Heat Loss
Heat lost by hot water that is sitting passively in a storage tank or pipes. Super-insulated hot water tanks greatly reduce this loss.


 


A.O. SMITH VOLTEX WATER HEATER
Whille it’s not a solar-ready model, this super-insulated hot water heater would be an excellent solar backup. It uses a unique hybrid electric water heater to borrow heat from ambient air to produce hot water and can operate in several modes, each offering a different level of efficiency. www.hotwater.com


FREEWATT COGENERATION SYSTEM (ECR INTL.)
The Freewatt Plus Warm Air system captures waste energy from a furnace component and converts it into electricity, producing 1.2 kW whenever the furnace is running. It also provides backup power during an outage. www.freewatt.com


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GreenBuilder 11.2010

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