Glycol Replacement In Solar Panels

Antifreeze fluids degrade over time and normally should be changed every 3 5 years.

Glycol replacement in solar panels.

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. 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 other factor specific to solar glycol is is ability to completely vaporize or steam when stagnation temperatures are present. 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.

Most solar thermal systems use antifreeze as the liquid to transport heat from the solar panel to the cylinder. The antifreeze is normally non toxic propylene glycol as opposed to toxic ethylene glycol. For solar thermal applications mixtures based on propylene glycol or the green glycol are recommended. Sentinel r100 solar thermal fluid is glycol based and designed for use in solar heating equipment operating up to 200 c.

Most glycol will break down and become acid needing immediate replacement if those temperatures are reached. Air in the loop can cause pump. 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. However you should always mix as much water as possible with your choice of glycol product as simple water is the ideal solar fluid.

It s non toxic biodegradable and relatively stable. When commissioning a pressurized glycol solar hot water system it is essential that all the air in the solar loop is removed. An antifreeze change may be required for your solar system. However there are a few drain back systems that only use water.

All glycol products used in solar fluid mixes come with a dilution chart an example of which is shown below. During static conditions the solar collectors should be completely empty so that the thermal fluid is not exposed to extreme temperatures. 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.