Solar water heating systems almost always require a backup system for cloudy days and times of increased demand.
Indirect solar water heating system definition.
Conventional storage water heaters usually provide backup and may already be part of the solar system package.
Swh systems which do not include a heat exchanger are called direct systems shown in fig.
Direct solar water heating systems pass potable water through the thermal collector that eventually flows directly to the desired application the faucet the showerhead etc.
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.
Solar water heating swh is the conversion of sunlight into heat for water heating using a solar thermal collector a variety of configurations is available at varying cost to provide solutions in different climates and latitudes.
Indirect solar water heating systems circulate a fluid typically a mixture of water and glycol in a circuit between the rooftop thermal collector and a heat.
Indirect solar water drainback systems are also a indirect design that use a heat exchanger to separate the collector loop from the potable water.
An indirect water heater can also complement a solar collector providing any additional heating that cannot be supplied with solar radiation alone.
Another benefit of indirect circulation systems is that they can be attached to multiple heat exchangers and used to heat different lines of water.
6 4 while the swhs which are fitted with heat exchangers are called indirect systems shown in fig.
Swhs are widely used for residential and some industrial applications.