Glycol Solar Panel Loop

Propylene glycol pg has become the most common heat transfer fluid used in closed loop solar heating systems that contain antifreeze.

Glycol solar panel loop.

In all three scenarios if a glycol fluid is used the residual glycol remaining in the panels becomes acidic and can cause corrosion issues. 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. 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. Perhaps higher boiling temperature.

Always mix in as little glycol as possible to keep optimum efficiency but never risk burst pipes. 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. This type of system uses solar panels also known as solar collectors that heat a propylene glycol mixture. Glycol closed loop solar thermal systems.

Glycol or some equivalent antifreeze fluid fills the collector and associated routing pipes. Are there advantages to running at 30 versus 20 psi. I ve been running at 30 psi for years but it s now working fine at 16 20 psi. This is known as charging the system.

When you re choosing a glycol bear in mind the following. Most new solar homes feature a variation of one kind or another. Air in the loop can cause pump. The type of system affects overall system design and each type of system has strengths and weaknesses.

When commissioning a pressurized glycol solar hot water system it is essential that all the air in the solar loop is removed. This is obviously catastrophic for any solar thermal installation and must be avoided. Never use less than 20 glycol in the mix. Closed loop active antifreeze systems are the most versatile and failsafe of all the solar supplemental water heating systems.

My system is two stiebel eltron sol 25 collectors a stiebl eltron sbb300 tank and new grundfos. A special water heater tank incorporating a heat exchanger works in conjunction with one or more flat plate roof mounted collectors. This glycol mixture is a non toxic food grade anti freeze. A closed loop often referred to as a glycol or anti freeze system a drainback system.

It has a long track record over many decades in this application and is widely available from a number of sources. What s the appropriate pressure for a glycol closed loop.