Glycol Solar Panel Loop

Most new solar homes feature a variation of one kind or another.

Glycol solar panel loop.

This type of system uses solar panels also known as solar collectors that heat a propylene glycol mixture. What s the appropriate pressure for a glycol closed loop. The type of system affects overall system design and each type of system has strengths and weaknesses. There are two main types of solar hot water systems.

This is known as charging the system. The primary difference between the two system types is that water is used for heat transfer in a drainback system and a glycol solution is used for heat transfer in a closed loop system. Glycol closed loop solar thermal systems. Never use less than 20 glycol in the mix.

In the case of the closed loop solar heating system the htf is typically a mixture of water and propylene glycol. It has a long track record over many decades in this application and is widely available from a number of sources. In all three scenarios if a glycol fluid is used the residual glycol remaining in the panels becomes acidic and can cause corrosion issues. I ve been running at 30 psi for years but it s now working fine at 16 20 psi.

This glycol mixture is a non toxic food grade anti freeze. When commissioning a pressurized glycol solar hot water system it is essential that all the air in the solar loop is removed. Always mix in as little glycol as possible to keep optimum efficiency but never risk burst pipes. A special water heater tank incorporating a heat exchanger works in conjunction with one or more flat plate roof mounted collectors.

Never use more than 60 glycol in the mix. Glycol or some equivalent antifreeze fluid fills the collector and associated routing pipes. Propylene glycol pg has become the most common heat transfer fluid used in closed loop solar heating systems that contain antifreeze. When you re choosing a glycol bear in mind the following.

Perhaps higher boiling temperature. Are there advantages to running at 30 versus 20 psi. Closed loop active antifreeze systems are the most versatile and failsafe of all the solar supplemental water heating systems. While stagnation situations do not happen often or for extended periods of time when they occur glycol degradation potentially can do enough damage that early replacement of the fluid and parts of the panel might be necessary.

This is obviously catastrophic for any solar thermal installation and must be avoided. The process of filling the plumbing system with this antifreeze while purging all the air out must be done systematically and in the right order.