Closed Loop Antifreeze Solar Water Heating System

The down side is two heat sources.

Closed loop antifreeze solar water heating system.

Glycol or some equivalent antifreeze fluid fills. Closed loop solar water heaters have few limitations with collector placement the collector loop is antifreeze filled and are permanently charged. Closed loop solar water heater systems sometimes referred to as anti freeze or glycol systems include the heat collectors insulated piping a circulating pump an expansion tank a hot water storage tank a heat exchanger solar fluid usually a solution of water and nontoxic propylene glycol antifreeze a controller valves and gauges. In systems that use other types of heat transfer fluids such as glycol an anti freeze scaling can occur on the surface of the heat exchanger that transfers heat from the solar collector to the domestic water.

All water heaters waste heat energy even when the burner is off and the unit is sitting idle between heating cycles. Scaling may also cause valve and pump failures on the potable water loop. Most new solar homes feature a variation of one kind or another. 42 home power 95 sdhw.

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. Closed systems are often used in second homes or primary residences in areas prone to long power outages. Hydronic heating systems must be filled with water to provide the heat transfer fluid htf that makes them work. A special water heater tank incorporating a heat exchanger works in conjunction with one or more flat plate roof mounted collectors.

Covers closed loop antifreeze systems and drainback systems. Very good articles on selecting the components for a closed loop solar hot water heating system suitable for cold climates. In the case of the closed loop solar heating system the htf is typically a mixture of water and propylene glycol. Installation basics for solar domestic water heating systems chuck marken and ken olsen.

Lots on installation detail. Heat exchangers in the storage tank eliminate a pump but make eventual tank replacement more. If freeze protection is an issue than a closed system with anti freeze is a good idea. Propylene glycol and the new bio green are common antifreeze materials we have several options for exchanging the heat to the clean domestic hot water.