Active indirect systems in which a heat transfer fluid like propylene glycol is heated up within the solar collectors and then transfers the heat to the water supply with a heat exchanger in a closed loop system.
Indirect solar water heater system.
Conventional storage water heaters usually provide backup and may already be part of the solar system package.
Solar water heating systems almost always require a backup system for cloudy days and times of increased demand.
The ite as well as the its can be part of a solar water heating system.
Swh systems which do not include a heat exchanger are called direct systems shown in fig.
Indirect systems water is heated directly into solar collectors and circulating in your home it is best suited for cold or freezing conditions where the absence of heat exchangers means that cold cold water cannot be heated effectively.
6 5 16 in a direct system the service water is directly circulated between the water tank and the collector while in an indirect system a heat transfer fluid usually antifreeze distilled water.
Instead of relying on glycol for freeze protection this system allows all the water in the array to drain back from the array and into a storage vessel in the solar loop when the pump is turned off.
The optimum installation can be constructed by using different accessories.
6 4 while the swhs which are fitted with heat exchangers are called indirect systems shown in fig.
Indirect solar system ite.
Some heat loss occurs while the transfer fluid circulates the system.