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ST can be a liquid heating system or an air heating system. Liquid or "Hydronic" is the most popular type that we work with. Air systems work well for daytime heating when the sun shines.  

In Iowa we use two different types of liquid collection systems - Closed Loop Glycol & Gravity Drainback.

Closed loop glycol is a system that will work with any type of construction. The system is pressurized and always full of fluid. Propylene glycol and water mixture is the heat transfer fluid. PG is a non-toxic antifreeze fluid and is freeze resistant when properly mixed.

Gravity drainback is a system where the solar collectors only have the fluid circulating through them when the sun is out and heat is needed in storage. At the end of the collection day,  during overcast skies, and at night, the solar collector fluid drains back to a holding tank, or the main storage tank. Water with or without propylene glycol is the heat transfer fluid. 100% water has the best heat transfer characteristics.  Most all new construction projects can use the gravity drainback design.

Domestic Hot Water (DHW) sytems heat your potable water using a pre-heat tank with a heat exchanger inside the tank, or with an externally installed heat exchanger. A fossil fuel back-up is needed for those peroids of times when the suns energy is not sufficient. 

Space Heating for new construction uses hydronic Radiant Floor Heat (RFH) with crosslinked polyethylene tubing (PEX). In order to maximize ST efficiency we use closer tube spacing than conventional RFH. There are many factors that influence the design of these systems. In all cases a back-up heat source will be needed. ST storage and fossil fuel back-up are always automatically controlled, the two heat sources are never used at the same time in order to avoid artifically heating ST storage.

Swimming Pools can easily be heated with ST. A typical installation uses polycarbonate collectors fastened to a roof or ground mounted framework close as possible to the pool. Using the pool pump and filter system you already have, an automatic control and low voltage motorized valve diverts the pool water through the solar collectors. These systems are gravity drainback, at the end of the collection day or when no heat is needed, the collectors are empty.