A closed loop often referred to as a glycol or anti freeze system a drainback system.
Closed loop system solar water heater.
A typical closed loop solar water heating system consists of.
Solar controller to automatically control the pumps.
The type of system affects overall system design and each type of system has strengths and weaknesses.
The primary difference between the two system types is that water is used for heat transfer in a drainback system and a glycol solution is used for heat transfer in a closed loop system.
Most new solar homes feature a variation of one kind or another.
Heat exchanger to exchange the heat between the hot solar panel antifreeze and the clean potable water.
Sized for family load.
There are two main types of solar hot water systems.
Indirect closed loop solar glycol systems use propylene glycol as the heat transfer fluid in the solar array to overcome issues of freezing glycol can tolerate 60f in high concentrations and eliminate scaling.
A special water heater tank incorporating a heat exchanger works in conjunction with one or more flat plate roof mounted collectors.
Closed loop active antifreeze systems are the most versatile and failsafe of all the solar supplemental water heating systems.
The glycol is separated from the potable water by means of a heat exchanger that transfers the energy from the array into the storage tank.
Closed loop systems use a heat transfer fluid to collect heat and a heat exchanger to transfer the heat to household water.