Evacuated Tube Solar Hot Water

Heating water can be one of the largest household expenses. In fact, electric hot water systems can cost in excess of $1000 a year to run. It is for this reason that many people are switching to solar hot water systems, which are more expensive to install but have lower overall running costs. Solar hot water systems have been used in Australia for many years, but a recent development in solar hot water has created a more efficient system that costs virtually nothing to run.

Evacuated Tube Solar Collectors

evacuated tube solar hot water installed on a roof frame.An evacuated tube hot water system is made up of glass tubes that are fused at the top and bottom. The air from the tubes is evacuated (hence the name) to create a vacuum, which reduces the heat loss to the environment. The tubes contain a thin heat pipe made of copper (this runs through the centre of the glass tube) that is connected to a slow flow pump. Water slowly passes through the tubes and it is heated by the sun. This water is then pumped into an insulated storage tank, which can be used during the day or night. Depending on the size of the system the hot water is constantly available without the need for an electric booster.

Development of the technology

Evacuated tube technology was developed in Australia in partnership with the New South Wales government. Once the technology was developed it was sold to China and it is now the most common form of solar hot water in this region.

Advantages

Superior Heat ExtractionThis is the main advantage of this type of solar hot water system. Evacuated tube systems can heat water in almost any conditions and they don’t require constant direct sunlight. The vacuum system creates a very high efficiency system, which means that an electric booster is required less often!
Non-standard InstallationDue to the higher efficiency these systems can be installed in areas where the sun is not an an optimal angle. They can also be installed in a stand alone ground installation with a specially designed frame.
DurabilityThese units are extremely durable and can be used in almost any area. They are capable of working to -12°C.
RepairThese units are far cheaper to repair than other solar systems should they be damaged.

Cost and Rebates

The cost of an evacuated tube solar hot water system depends on a number of factors such as eligibility for government rebates, size of system and tank, brand of system, as well as the difficulty of install. For example, a standard install and added government rebates you may find a supplier offering a special price of about $1000 for a 30 tube and 250 litre system. On the other end of the scale a difficult install of a 40 tube and 350 litre Apricus system, without government rebates, can easily cost upwards of $5000.
There are many state and federal government rebates for these systems and it is important to ask your installer about which rebates you are eligible for before installing. You also need to understand Small-scale technology certificates (STCs), which you may be eligible for when installing a renewable energy system such as solar hot water. This is part of the Small-scale Renewable Energy Scheme and there are many benefits for home owners available. See the Clean Energy Regulator website for more details.

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