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The Drain-back System - Elegant Simplicity
There are various designs of solar system available, the simplest
uses a drain-back cylinder to store the fluid in the solar
circuit when the pump is not running. In this way the solar
collector is drained of fluid and therefore cannot freeze
in winter or overheat in summer. This simple system avoids
many of the problems of other systems:
• No gauges to watch
• Operates at atmospheric pressure
• Can be filled with ordinary tap water – no antifreeze
required
• Sealed system, does not need to be topped up
Have a look at our FAQ's for more information.
Pressurised Systems
There are cases when the drain-back system can’t be
used (for example, when the collector is lower than the hot
water cylinder), in such cases a well designed pressurised
system is used. Solaris pressurised systems uses solar rated
antifreeze to give frost protection and an expansion vessel
to allow the fluid to expand as it gets hot.
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Drain-back |
Pressurised |
| Frost protection |
collector empty |
Anti-freeze |
| Overheat protection |
collector empty |
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| Direct/indirect |
indirect |
indirect |
| thermo-siphoning prevention |
collector empty |
check valve required |
| Restrictions |
Collector must allow sufficient head height |
None |
All of the systems we recommend are indirect systems, meaning
that the hot water cylinder has a second heat exchange coil
for the solar circuit. This results in a robust system without
the problems (e.g. lime-scale) associated with direct systems.
System sizing
We insist on conducting a thorough survey for all our customers
to ensure the system is specified correctly. Our surveyor
will calculate the appropriate system size dependant on the
number of occupants, tilt and orientation of the collectors,
shading etc. As a rule of thumb, 1m sq of flat plate collector
is required per person.
Why not arrange your survey now or click here to get an instant on-line quote.
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