Heating water for use in your home is the singularly largest use of energy in virtually every domestic dwelling. It uses more electricity, gas or oil than cooking, lighting and anything else you can think of put together, accounting for up to a third of a typical homes total power usage.

So wouldn't it be wonderful if we could use a more cost effective, alternative and virtually free method of heating our domestic hot water instead. Well, there is a solar thermal option available for you to use no matter what type of climate you live in which is proved by using a Flat Plate Solar Collector. Flat plate solar collectors are easy to use, easy to install, and more importantly are powered simply by the heat of the sun.

Advantages of a Flat Plate Solar Collector

Solar power in the form of the suns heat energy is free. So after the relatively inexpensive outlay of installing a solar hot water heating system, you will start to benefit quickly from a return on your investment.

The technology and design of the modern flat plate solar collector has advanced so rapidly over recent years that solar thermal water heating systems can now work in almost any climate or geographical location around the globe. Using the power of the sun as a carbon neutral energy source allows you to reduce your usage of fossil fuels so not only do you cut your monetary costs, you also reduce your carbon emissions and therefore your carbon footprint. By directly heating the water itself, the solar hot water can be stored in a tank in similar fashion to that of a conventional heating method, providing plenty of hot water when needed.

So How Do Flat Plate Solar Collectors Work?

The "flat plate solar collector" works by simply absorbing the energy from both the sun's direct rays and any additional reflected solar energy around it. Made from either aluminum or copper due to these metal's heat conduction abilities, they look like, as the name implies, just like large flat panels. You have probably seen examples of these on roofs of houses in the area in which you live.

As black is a colour that easily absorbs heat, they are either chemically etched or even painted this colour to make their energy capture as efficient as possible. Affixed to this blackened plate is a network of copper tubes (called risers), that contain the water or equivalent heat transfer fluid such as a glycol solution used in closed loop systems. These risers are attached to the solar thermal panel in such a way as to ensure the maximum possible surface contact for efficient energy transfer to the water inside the tubes. So the flat plate solar collector absorbs the heat of the sun, using this energy to get hotter and hotter which in turn then heats up the water flowing through the risers.

The solar plate and pipes are protected but exposed to the sun by either a plastic or a glass glazing material, as well as being sealed within a wooden or metallic frame. Because the glazing has very little heat absorbency properties, the vast majority of solar heat passes straight through it and is taken absorbed by the flat panel. This glazing also creates an insulating air space that prevents the captured heat from escaping and returning back to the surrounding atmosphere.

So Which Type of Solar Thermal System Will I Need?

Depending on your location, budget and individual needs, there are different types of solar thermal heating systems available. In general, they are generally classified as follows; open loop types, closed loop types, passive systems and active systems. Each type of solar thermal system has its pros and cons depending upon the way that the hot water is transferred around the solar hot water system. Generally gravity fed are passive systems while pumped fed are active systems.

The amount of solar panels that are needed to provide all the hot water for a household depend on a variety of issues. Naturally, the smaller the system, the cheaper it will be to purchase and install, and therefore the sooner you will recoup a return on your initial investment. Whilst factors such as how many people live in a house and the maximum temperature you require your water to be can also reduce the size of the system needed, generally you can estimate your needs in the following manner:

1. A single, 20-30 square feet solar panel has the ability to heat around 60 gallons or 300 liters of water per day. This is approximately the required size of an average hot water storage tank.


2. Each person uses on average 1.5 to 2 gallons of hot water per day.


3. 10-16 square feet of solar panel will provide the required amount of solar hot water for one person.

Therefore a normal family of four will require about 40-60 square feet of flat plate solar collector area to provide 60-120 gallons of hot water storage. As the average flat plate solar collector is around 32 square feet, or 8ft x 4ft, this would equate to two solar thermal panels.

Of course, one thing most types of solar panels are unable to do is track the sun as it meanders across the sky each day. To counter this, they are fixed at a southerly angle (in the northern hemisphere, the opposite in the southern). This means that they receive the optimum amount of sunlight at noon, when the sun is high in the sky, as well as during the other points of the day. The more available solar energy from the sun, the more efficiently the system can heat water.

Because there are a variety of different flat plate solar collectors and solar heating systems available on the market, it pays to do your homework first before making the choice of which type is best for your home or installation. A little thought and research beforehand will help ensure that you fit the best flat plate solar collector and solar hot water heating system for your home and families needs.