Solar Water Heating System Temperatures

Your Average Solar Water Heating Temperatures Will Vary – this is why you need a system to accommodate both extremes

Solar water heating temperatures fluctuate by large amounts during the day and night as well as throughout the year i.e. summer and winter. Obviously the water is heated during daylight hours using the suns energy and if the water is not used then it needs to be stored in an insulated cylinder ready for use to provide hot water on demand.

During the summer months, solar thermal panels can provide up to 75% of a households hot water needs and in the winter months this can drop down to 25%.

There are two main types of solar thermal heating collectors. These are the evacuated tube and the flat panels. The evacuated tube heater panels work harder and are more efficient at converting the suns energy into hot water. These are made of glass tubes, and the gap between the tubes is a vacuum which gives its increased efficiency, plus they will not freeze when the temperature drops during the winter months. However the cost of installation is higher than flat panels.
The flat plate solar collector panel is made up of copper tubes which harvest the suns energy. These are not as efficient and will freeze unless an anti-freeze is pumped round the system.

However, the flatplate panels are currently more popular with home owners because they are lighter and easier to fit and more importantly there are fewer things to go wrong and maintenance is kept to a very minimum.

What if the Water is To Hot

A solar thermal hot water system design will include a sensor and mixer valve on the outlet pipe from the central hot water storage cylinder which feeds your households plumbing system. If the water that comes out is too hot, it will mix it with cold water from the mains supply.

What if the Water is To Cold

As a backup, the central hot water holding tank is also fed with hot water from your homes boiler or it has an electric coil fitted or both. So if the water temperature drops below a certain point, one of these backup systems will cut in.

And so this is how you get the figure 75% during the summer months and 25% during the winter months – for the amount of hot water your solar panels will produce.

If anybody would like to expand on this or specify what solar water heating temperatures they are getting from their solar panels then feel free to leave a comment below.


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