What are the disadvantages to the three-season solar water heating system?
• It is susceptible to freezing. • The system is dependent on the owner being present to drain it when the weather is cold. • There is an overall limit to the size of this system when it’s plumbed to a water heater of a specific capacity. The active closed-loop solar water heating system uses any type of fluid in the collector to storage loop that won’t freeze at low temperatures. The heat gathered in the collector is then transferred to the water in the storage tank through a heat exchanger. What are some fluids that don’t freeze that you can use? Glycol, silicon oil, and methanol would work, but never automotive anti-freeze. It is poisonous. The most commonly used heat transfer medium is polypropylene glycol, which is a food-grade dough extender used in the baking industry. It costs about $20 a gallon and is mixed with water. A 10% mixture will protect the collectors down to 20-25°F. Depending on locations, a higher amount may be needed. While glycol is non-toxic, it can break down o
