Closed Loop Antifreeze Solar Water Heating System

Glycol or some equivalent antifreeze fluid fills.

Closed loop antifreeze solar water heating system.

Closed systems are often used in second homes or primary residences in areas prone to long power outages. Of closed loop anti freeze sdhw systems hereinafter referred to as closed loop sys tems. 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. Closed loop solar water heaters have few limitations with collector placement the collector loop is antifreeze filled and are permanently charged.

Closed loop active antifreeze systems are the most versatile and failsafe of all the solar supplemental water heating systems. In the case of the closed loop solar heating system the htf is typically a mixture of water and propylene glycol. 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. Lots on installation detail.

Installation basics for solar domestic water heating systems chuck marken and ken olsen. 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. All water heaters waste heat energy even when the burner is off and the unit is sitting idle between heating cycles. Very good articles on selecting the components for a closed loop solar hot water heating system suitable for cold climates.

42 home power 95 sdhw. Covers closed loop antifreeze systems and drainback systems. 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. Most new solar homes feature a variation of one kind or another.

The down side is two heat sources. Scaling may also cause valve and pump failures on the potable water loop. Installation basics for sdhw systems in hp94 covered aspects of installation common to most solar water heating installations such as collector location and mounting pipe runs soldering and insulation and the control system. If freeze protection is an issue than a closed system with anti freeze is a good idea.