Choosing a Solar Hot Water Cylinder

One of the first question we ask customers looking to install a Solar Thermal hot water system is: What cylinder do you have at the moment? The Solar Hot Water Cylinder is arguably the most important and influencial part of a Solar Thermal hot water system design it determines:

* How much hot water will be available for use in the property
* How big or how many solar collectors it will take to heat all of the water
* What type of solar collector to use
* The Solar Thermal Design to implement

If you get the size and type of cylinder for the installation right then usually the other elements of the system will fit nicely into place.
Single Coil Cylinders:

Single Coil Cylinders can be used with Solar Thermal installations, if you already have a water heating system with a single coil cylinder then you do not neccessarily need to replace it. When using a single coil cylinder we use a 'direct' heating method, this is where the hot water from the collector warms the water in the cylinder directly whilst returning colder water to the collector for re-heating. More information about "Direct" heating methods can be found here Solar Thermal System Design.
Twin Coil Cylinders:

Having a twin coil cylinder installed is like having a combined dedicated solar cylinder and a normal cylinder at the same time. Fluid in a closed system circulates from the Solar Collector to the Cylinder through a coil running through the cylinder. Colder water is returned to the collector to be heated. The second coil is connected to a traditional boiler or other heating source. A Twin Coil cylinder is essentially getting hot water from 2 independent sources. When looking at twin coil cylinders, long thin ones are generally better.

Investing in a twin coil cylinder is great for those who:

* Need to replace or upgrade their existing cylinder anyway
* Want water to be heated from more then one source simultanously