Understanding Battery Capacity
As you cannot see electricity, it is hard to confirm the exact amount of energy available in a battery bank.
As you cannot see electricity, it is hard to confirm the exact amount of energy available in a battery bank.
If you're planning a solar thermal installation for a large building or a communal property such as apartments, you may need to consider a very large water storage tank. This is also true if your project is solar space heating – both of these installations require outsized tanks. Think big: we're talking between 300 and 500 gallons, here.
In the world of renewable energy, solar thermal – heating water with the sun's power – is understandably the oldest and most mature field. That's because it's so simple: the sun has heated standing water for millennia and solar thermal systems simply add a technological aspect to improve efficiency, reliability and ease of use.
The fact that solar thermal has been around for a while has many benefits:
You may think that solar power systems are a completely modern idea: they're not. In fact, people have used solar power since prehistoric times and we only think it's a new invention because it's so frequently coupled with electricity. In fact, electricity nearly caused the death of the solar thermal industry.
You may be surprised to learn that humans have used solar thermal systems in one form or another not just for decades, but for thousands of years. They may not have installed complicated electrical control systems, clever pumps and man-made materials for improved efficiency but they certainly knew a great deal about harnessing the sun's energy and using it to provide hot water. As far back as early cave dwellers, there are signs that humans understood the most basic form of the sun's power.
If you're installing a solar thermal system in a location that gets a lot of direct sunlight and you're doing it on an industrial scale, you might want to consider concentrating collectors. Unlike normal collectors, these won't work with indirect sunlight, but they're a lot more efficient than any of the other types if your location, scale and budget allow their use. Concentrating collectors use the simple scientific principles of focusing light to concentrate the sun's energy onto a single point.
Working out how many PV panels you need to cover your electricity requirements is not a simple matter. Here's an example walkthrough so you can get a handle on your own calculations.
Walking around our imaginary house, we list every appliance, gadget and other plug load that uses electricity. Next to them, we write down the power use and the estimated number of hours they're switched on in summer and winter.
Our table looks a bit like this (though a lot longer):
You know what we're going to say: talk to a professional. The most reliable estimates of what equipment you'll need come from people who've already installed dozens of renewable energy systems in your area. However, we know you're going to try to figure it out for yourself, so here are some guidelines!
There are three main ways of figuring out how much PV space you'll need: daily use, net-zero and a simplified guesstimate.
Photovoltaic panels are a 3-2-1 proposition: they come in three flavors, two installation types and with one additional option. The three flavors are monocrystalline, polycrystalline and amorphous; the two installations are building-integrated or panels; the additional option is a tracking mechanism.
Photovoltaic panels (or PV panels) are typically flat, rectangular boxes full of cells which capture the sun's energy and turn it into DC (direct current) electricity. This current can be converted into AC (alternating current) by means of an inverter and used in a normal, grid-connected home.