How Do Solar Hot Water Systems Work?
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by: ElliotPatel | Total views: 17 | Word Count: 658
When it comes to solar energy, one of the ways that it can be used is to create electricity. That is done with photovoltaic solar panels. It's also possible to get your water heated through solar hot water systems though, and it is this form of solar energy which we will be focusing on here.
Solar Collectors
The most important part of solar hot water systems are of course the solar thermal panels. They are what take the heat from the sun, and transfer it to the water in your system. They come in two basic forms.
One of the forms that solar collectors come in is as flat-panels. In these, they have an absorber plate at the bottom of the panel, which is what collects the heat from the sun. That heat is then transferred to pipes running through the panel. The pipes will either have the water that is to be heated running through them, or else something which will then heat the water later.
Alternatively, there are the evacuated-tube solar collectors. They have this name because they are a series of tubes, and around the outside they have a space which is a vacuum, meaning there is no air in there. There is no nothing in there. This helps with the insulation.
When it comes to the efficiency, it's the evacuated-tubes which win. That's because their absorber plates are not just on the bottom. Instead they run all the way around the tube, so they can capture the sunlight effectively whatever angle it is coming in at. Also, this means that there is a larger surface area available for the absorber plates.
Before moving on to talk about the circulation systems, a couple of misconceptions that many people hold have to be sorted out. The first thing to mention is that it doesn't need to be a hot day in order for the solar thermal panels to work, they don't even need bright sunlight. It does help, as you'd imagine, but they will work all year round, as long as it is day time. Also, it doesn't have to be direct, they work through cloud cover as well.
Circulation Systems
The decision of the kind of solar collector is not the last one that you are going to have to make in terms of the make up of your solar hot water systems. Adding solar thermal panels in to the mix makes the system a bit more complicated, and you have to decide how best to manage this.
As well as requiring a new boiler, it is also possible that the location of some of the elements that make up a circulation system are going to have to be rearranged. In large part though, that is going to come down to whether you would prefer to have an active or a passive system in place.
If you choose "active" that means pumps will be circulating the water. That's the more efficient way of doing it. A cheaper way of doing it, however, is to use a passive system, which uses gravity and heat convection to circulate the water. In that case, everything has to be arranged in a specific way so that it works correctly.
Finally you'll have to choose between a direct and indirect circulation system. This has to do with how and when the water is heated. If it goes directly to the roof, to be heated by the solar collectors directly, that's a direct system of course.
If a heat transfer substance is used instead, so that it is what is heated by the solar panels, then that's an indirect system. Although that doesn't sound as good, it's actually better for colder climates because the heat transfer substance will not be able to freeze, whereas if the water is taken to the roof then on very cold days it may well freeze.
So that's a brief overview of how solar hot water systems work, and the sorts of options available when you are getting one.
About the Author
Author Jude Turner writes more about solar energy at Solar Hot Water Systems. Discover the amount of money it's possible to save, as well as how it all functions. It is also possible to get a free installation quotation.
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