Green Planet

Save energy & money with solar hot water systems

August 25, 2016 Plumbing

Did you know that hot water systems are the ‘single most energy intensive appliance in the home’?  In other words, hot water systems use the most power of any system – especially in a family home.

And did you know that solar hot water systems can cut your power costs by up to 75%?

So what are solar hot water systems, and how do they work?  And more importantly, how do you save money and energy with them?

How Do Solar Hot Water Systems Work?

Most solar hot water systems use solar collectors or panels to absorb energy from the sun. Water is heated by the sun as it passes through the collectors, and then flows into an insulated storage tank for later use.

There are two types of collectors used in a solar hot water service

Flat plate collectors

Evacuated tubes

Flat plate solar collectors

Flat plate collectors work on copper pipes running through a glass covered collector, often connected to a water storage tank on the roof. The sun heats the copper pipes and the water inside is heated.  The hot water is then siphoned out of the storage tank through ‘thermal siphoning’. Thermal siphoning works on the system where warm water rises – therefore as the water heats up, it rises above the cold water and is siphoned out from the top.

Evacuated tube solar collectors

Evacuated tubes consist of two glass tubes fused at the top and bottom. The space between the two tubes is ‘evacuated’ to form a vacuum.  A copper pipe (called a heat pipe) is located inside the evacuated tube and carries a small amount of purified water.  The heat pipe is also ‘evacuated’, and so this liquid boils at a very low temperature (around 30°C).  It turns to vapour and rises to the top of the heat pipe.  (There is no water running through the tubes, the heat pipe simply transfers the heat from inside the tube to the cooler water running through a manifold, and this is how the water is heated.)

As this process happens, the vapour inside the heat pipe condenses and turns back into liquid, then returns to the bottom of the heat pipe … and the process begins again!

Because the tank is insulated, the hot water can be used at night or the next day.

As you can see, the evacuation tube system is extremely efficient, and can extract the heat out of the air on a humid day, and does not need direct sunlight – such as early in the morning or in the late afternoon.

As solar hot water is usually not enough for a household’s total hot water needs (especially when the hot water is used at night and the system does not reheat till the sun is out), the storage tank is usually fitted with a booster. This may be powered by electricity, gas or solid fuel, and heats the water when there is not enough sunlight, such as on cloudy or wet days, or during winter when there are fewer daylight hours.

Some solar hot water systems also have built in frost protection (to -15°C) to prevent damage in frost prone areas.

Hot water and household energy usage – greenhouse gas emissions

According to the Department of Environment and Climate Change NSW, electric and gas hot water systems account for approximately 20% of a household’s greenhouse gas emissions. Most companies offer discounted prices on solar hot water systems, and  government rebates are also available for their purchase.  Therefore, by installing a solar hot water system you will reduce your greenhouse gas emissions and also save up to 75% of your water heating costs!

Green Planet Plumbing are experts in solar hot water installation and repairs.  We are a locally owned and family operated business, trading since 2008, and we provide a range of plumbing services throughout the Lake Macquarie, Newcastle, Central Coast and Hunter Valley regions.  You can rely on our professional team for efficient hot water services.  We can help you to choose a solar hot water system that suits your needs.

Contact us today 0414 185 822, or complete your details on our Home page on our website.

Enquiry Form

  • This field is for validation purposes and should be left unchanged.