Typically in solar applications the valve port opens on descending temperatures allowing the near freezing water in the solar panel to be discharged and replaced with warmer supply water.
Antifreeze solar panels.
All glycol products used in solar fluid mixes come with a dilution chart an example of which is shown below.
Recommended dilution 40 providing total volume of 12 litres for use in solar systems.
Solar panels can also directly heat water by heating water filled pipes within the solar panels or by heating a transfer fluid such as antifreeze usually propylene glycol.
Hydrocarbon oils hydrocarbon oils have a higher viscosity and lower specific heat than water.
The photovoltaic solar panels or pv solar panels convert the sun s energy into electricity which then can be used to heat water.
These types of systems are pressurized and should only be serviced by a qualified solar heating professional.
However there are a few drain back systems that only use water.
Most solar thermal systems use antifreeze as the liquid to transport heat from the solar panel to the cylinder.
5 litres solar antifreeze.
The antifreeze is normally non toxic propylene glycol as opposed to toxic ethylene glycol.
However you should always mix as much water as possible with your choice of glycol product as simple water is the ideal solar fluid.
Antifreeze fluids degrade over time and normally should be changed every 3 5 years.
Currently i m planning to construct a small green house 12 x16 x8 and wanted to heat the green house using evacuated tubes.
It s non toxic biodegradable and relatively stable.
Antifreeze fluids degrade over time and normally should be changed every 3 5 years.
Should be sufficient for most single and double panel systems.
Neat propylene glycol with additive package.
It has a long track record over many decades in this application and is widely available from a number of sources.
Using an antifreeze solution solar water heating systems that use an antifreeze solution propylene glycol or ethylene glycol as a heat transfer fluid have effective freeze protection as long as the proper antifreeze concentration is maintained.
The heated water would be stored in a simple insulated home built tank and the heated water would be circulated to pex tubing placed in the concrete floor when needed.
An antifreeze change may be required for your solar system.
They require more energy to pump.
What type of solar system do you have is it sealed or drainback a correctly installed drainback system should not require antifreeze sealed systems require a good quality antifreeze that will not break down with the high temperatures of solar it should also be a premixed antifreeze it is no good injecting a small quantity of antifreeze into the system as it will not mix and so will not protect the system premixed glycol is the best for solar and it should be used to fill the complete.
When the warmer water reaches the valve the port closes and water discharge stops.
