Solar Water Heating System Freeze Protection.

Solar water heating systems, use liquids as heat-transfer fluids and need protection from freezing as temperatures in Ireland fall below 6ºC.
We Do Not recommend that customers rely on the Solar panel or the system’s insulation to keep them from freezing. The main purpose of the insulation is to reduce heat loss and increase performance. For protecting the collector and piping from damage due to freezing temperatures, you basically have two options:

• Use an antifreeze solution as the heat-transfer fluid (Glycol).
• Drain the collector(s) and piping, either manually or automatically, when there's a chance the temperature might drop below the liquid's freezing point (Not Recommended).

Using an Antifreeze Solution.

Solar systems that use an antifreeze solution (Glycol) as a heat-transfer fluid have effective freeze protection as long as the proper antifreeze concentration is maintained. Antifreeze fluids degrade over time and normally should be changed every 3–5 years. Since these systems are pressurised it is not practical for the average homeowner to check the condition of the antifreeze solution therefore we provide this service.

Draining the Collector and Piping.

Solar systems that use only water as a heat-transfer fluid are the most vulnerable to freeze damage. "Drain down" or "Drain back" systems typically use a controller to drain the collector loop automatically. Sensors on the collector and storage tank tell the controller when to shut off the circulation pump, to drain the collector loop, and when to start the pump again.
Improper location or sensor failure can lead to failure to detect freezing conditions. The controller may not drain the system, and expensive freeze damage may occur.
Safety and Efficiency.
We want your system to work efficiently and safely we also believe the homeowner should not be expected to fully understand the operating of their solar system, therefore we recommend that the system should operate with the least amount of intervention from the homeowner.
This is achieved by using “closed loop” or “Pressurised Systems” with “Food Grade Glycol” as the transfer medium.
When used with a good quality controller the heat from your solar cylinder will not be used as a method of protection against freezing and you will not have to continuously check outside temperatures or have any concerns about your Solar System.