Antifreeze Solar Panels

All glycol products used in solar fluid mixes come with a dilution chart an example of which is shown below.

Antifreeze solar panels. Most solar thermal systems use antifreeze as the liquid to transport heat from the solar panel to the cylinder. An antifreeze change may be required for your solar system. 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 fluids degrade over time and normally should be changed every 3 5 years.

It s non toxic biodegradable and relatively stable. 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. It has a long track record over many decades in this application and is widely available from a number of sources. Antifreeze fluids degrade over time and normally should be changed every 3 5 years.

However there are a few drain back systems that only use water. They require more energy to pump. 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. 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.

Neat propylene glycol with additive package. Propylene glycol pg has become the most common heat transfer fluid used in closed loop solar heating systems that contain antifreeze. 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. Should be sufficient for most single and double panel systems.

This cycle will repeat as often as necessary to help prevent freezing. 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. Recommended dilution 40 providing total volume of 12 litres for use in solar systems.

The photovoltaic solar panels or pv solar panels convert the sun s energy into electricity which then can be used to heat water. When the warmer water reaches the valve the port closes and water discharge stops. 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. These types of systems are pressurized and should only be serviced by a qualified solar heating professional.