Saturday, March 29, 2008

Small-Scale Solar PV for Your Home

Not ready to spend thousands on a solar electric system to power your home? Consider powering a portion of your home with solar instead.

A few years ago this probably wouldn’t have been a good idea, since small home-based PV systems tend to be underused. After all, if you try to run your refrigerator with a small system you might return home from work some cloudy day and find a lot of spoiled food. Since most of us work or go to school during the day, power from a small system is typically used to charge batteries. That stored energy might be used for a few hours of TV viewing or to run a computer in the evening. But energy from the sun during peak sunlight hours could be more efficiently used to power a load. Better yet, mid-day power from the solar panels could power a load and charge batteries simultaneously.

You can easily build a system that will use power from the panels and batteries to run the load until battery voltage drops to a preset level. The load will then be automatically switched to AC from the power grid. A few years ago it would have taken a computer guru, or an electronics engineer to make that happen, but not today. Today the components you'll need are available at a reasonable cost, and it doesn’t take a scientist to hook things up.

By adding automation to a simple off-grid PV system you’ll be using as much of the free energy from the sun as your system is capable of processing, making the most of your renewable energy investment. You’ll be cutting your electric bill as much as possible, instead of under-using your solar panels and equipment. You can use a refrigerator and freezer as the load without worrying about food spoiling, and your batteries will be protected from over charging and from over discharging, extending their life.

The system is expandable. You can start on a small budget, and add to your system as funds become available. Once you see how well this works, and how little maintenance is required, you’ll want to make it bigger.

Does this idea appeal to you? Check out my blog archives for system design details, especially this one:

"I've automated my off-grid pv system"

You need not use the same system parts or configuration. My approach represents one of many ways to do it. You might discover other ways as you look at the capabilities of different brands and types of system components.

I’ll be happy to answer your questions. Just leave a comment.

John

3 comments:

d said...

Ah SJ, the RE madness has really bitten now. I'm trying to work out how to reduce my home's energy requirements and offset my business energy use at the same time (page still in progress):

http://www.earth.org.uk/towards-a-LZC-business.html

Though I'm going to have to think through how to avoid 'double counting' the emissions reductions this way, never mind keep the taxman happy!

BTW, I wonder if any of your visitors would be interested in taking the new poll on my front page in the spirit of your site?

Rgds

Damon

Anonymous said...

You have really great taste on catch article titles, even when you are not interested in this topic you push to read it

bewing said...

I am looking to install a small solar system, we have a double lot and the panels could be set up there and get sun most of the day or on the roof. The winters here are considerably more cloudy than spring and summer so I am looking at other possibilities such as wind.

I live in town but really want to reducue dependenace on the grid as much as posssible