Glycol for solar hot water systems

How much glycol should a solar thermal system use?

This is obviously catastrophic for any solar thermal installation and must be avoided. When you're choosing a glycol, bear in mind the following: Never use less than 20% glycol in the mix. Never use more than 60% glycol in the mix. Always mix in as little glycol as possible to keep optimum efficiency, but never risk burst pipes.

What happens if you use the wrong glycol in a solar water heating system?

If the wrong glycol is used in a solar water heating system, the fluid can break down rapidly. This can result in plugged collectors, blocked pumps, and in extreme situations systems that must be abandoned entirely.. Proper application and maintenance of the HTF can protect your water heating system to minus 60° Fahrenheit.

Which heat transfer fluid should I use for solar water heating?

Primarily referred to as glycol, the product comes in different formats, however SunEarth recommends usage of the Dow Chemical Dowfrost HD propylene glycol heat transfer fluid (HTF). Solar water heating systems have the unique characteristic of producing very high fluid temperatures during summer stagnation conditions.

How to choose the right glycol for a solar thermal application?

The following criteria could be used to choose the right type of glycol for a solar thermal application: High thermally stability at temperatures up to 350°F (177°C). Nontoxic. Good corrosion protection. High reserve alkalinity or good pH buffering.

How to optimize a solar thermal hot water system?

Selecting an efficient, stable fluid to transfer heat from the rooftop panel down to the hot water heat exchanger is a key step to optimizing any solar thermal hot water system. Solar rooftop panels can reach temperature exceeding 300°F (149°C).

Can PG be used in a solar heat collector system?

Propylene glycol (PG) has a long track record of being used in solar heating systems. In any hydronic closed-loop solar heat collector system, the heat transfer fluid is the lifeblood. It must be sealed and pressurized in the solar heat piping, much like the Freon fluid in a refrigeration system.