During static conditions the solar collectors should be completely empty so that the thermal fluid is not exposed to extreme temperatures.
Glycol replacement in solar panels.
Most glycol will break down and become acid needing immediate replacement if those temperatures are reached.
However there are a few drain back systems that only use water.
Solar glycol such as prosoltm l ht is rated to 425 f with short periods of up to 475f.
Sentinel r100 solar thermal fluid is glycol based and designed for use in solar heating equipment operating up to 200 c.
It is vital that you consult the chart to avoid mixing too little or too much glycol into your system too little will risk consequences in cold weather too much will reduce the mix s efficiency.
This is not always the case we will test the condition of your system before we do.
Food grade propylene glycol the other kind like normal antifreeze is quite toxic if ingested different uses have different formulations get the one for solar panels.
The renewable green alternative to ethylene or propylene glycol has a slower thermal degradation rate than both ethylene glycol and propylene glycol and outperforms propylene glycol s viscosity at lower temperatures.
The antifreeze is normally non toxic propylene glycol as opposed to toxic ethylene glycol.
All glycol products used in solar fluid mixes come with a dilution chart an example of which is shown below.
Antifreeze fluids degrade over time and normally should be changed every 3 5 years.
Air in the loop can cause pump.
It s non toxic biodegradable and relatively stable.
A solar collector mounted on the roof absorbs energy from the sun and transfers it to a medium usually a water glycol mixture which is then pumped to a coil in a tank where it heats up the water.
An antifreeze change may be required for your solar system.
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.
A conventional immmersion heater or gas boiler can be used to top up the temperature of the water particularly in winter or to provide extra hot water when required.
When commissioning a pressurized glycol solar hot water system it is essential that all the air in the solar loop is removed.
For solar thermal applications mixtures based on propylene glycol or the green glycol are recommended.