Solar PV Systems
Solar systems have been becoming more and more popular. There are basically two different types of system referred to as a “Solar System”. Both involve panels, usually placed on your roof but the similarity ends there. Here we are talking about Solar P.V. which is short for solar “photovoltaic”. You can tell by the name it means you are getting electrical power (voltage) from light (photo). This happens because the large panels on your roof are coated with a type of silicone that has some special impurities in it. When sunlight hits these impurities they react by giving off a small electrical charge. If you have enough of these small charges and you add them up they can produce enough electrical power to run some households or to augment the power you pull off the grid.
Solar Growth in the US
The solar world has been undergoing tremendous changes in the past decade. 10 or so years ago utility companies and the Federal government were offering substantial rebates and tax credits to jump start the solar industry. The panels themselves seem to be the hinge point as far as cost. Much research has been done in the U.S. and China. Cheap Chinese panels flooded the market a few years back and the price per kw dropped dramatically. The problem is the quality was questionable which gave the solar industry a bad name. And of course we had (and still have) some solar companies who take advantage of folks and charge much more than needed or talk folks into leasing or renting the panels or renting your roof space to them to place their panels on and they’ll give you a percentage of what is generated. The thing is, unless you own the equipment, the generous tax credits and rebates still offered in some areas will not belong to the homeowner but to the solar company.
Sizing Your Solar System
The goal when sizing a solar system for a home is to analyze a couple years electrical usage and set a target that gets the homeowner out of the top pricing tiers. If you are a PG&E electric customer you know the 3rd and 4th pricing tiers cost you triple or more than the 1st and 2nd tiers. So the goal is to at least take care of this top tier usage. You don’t want to generate more power than you use because at “true-up time” PG&E will only pay you a fraction of the price they charge you for the lowest tier usage. So the trick is to generate enough power to offset the real expensive power you buy which is usually the midafternoon on the hottest summer days. It’s unknown at this time whether City of Ukiah will extend their incentive for solar P.V. in 2015, but the 30% tax credit from the federal government is still active for solar equipment installed thru 2016. So if you have any thoughts about going solar, now is the time while you can still get almost one third of the cost handed back to you in the form of a tax credit. Just be aware that you must owe Federal taxes before you can claim this credit.
When we discuss a solar system for a client’s home we are talking about one of two types of system. The first is a solar P.V (or photovoltaic) which generates electricity to help offset the power consumed in a household. The type we are discussing here is the second type which is called “solar thermal”, or sometimes just called solar hot water.
Solar Hot Water Heating
This type of systems consists of some type of panel or exposed piping with water or other liquid flowing thru it that is exposed to the sunlight on your rooftop. The simplest type is just a coil of black plastic tubing laying across the roof. This tubing is full of water and the sun heats the water in the tubing which then flows to the water heater. This acts as a pre-heater so the water heater doesn’t have to run so long to heat up the water to the desired temperature. The sun has already pre-heated it. Another type has tubing that runs thru a panel but instead of water in the tubing it’s some other liquid that is heated by the sun. This liquid is then run thru a heat exchanger where the heat it has absorbed is transferred to water that is then allowed to flow into the water heater.
Offset Your Heating Costs with Solar Thermal
One of the benefits of this indirect system is the liquid heated can have anti-freeze base which means you don’t have to be so diligent about draining the water out of the tubing during possibly freezing weather. There is a style being tried now where instead of having a water heater down in the house or garage that stores the semi-heated water, there is instead a tank right on the roof that stores the heated water. An electric heating element then adds the heat needed so there is hot water all the time and no water heater tank hanging around.
If a person lives in an area without natural gas, where electricity or propane or other fuels must be used for water heating, solar should be considered. Just remember the solar hot water from the roof is only a pre-heater as most of the time the roof tubing can not provide enough heated water for all household usage. So you’ll always need another fuel to finish heating that water to the desired temperature. PG&E may still be offering a rebate for adding solar pre-heat to an electric water heater. Check it out.
Electricity is still the most expensive way to heat anything, be it water, air, or wet clothes.