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 exchanger that actually warms the potable water.
Direct vs indirect solar water heater.
Direct circulation systems vs.
Direct fired water heaters are solely dedicated to the job of hot water generation providing a faster heat up and response time compared with an indirect system which is in fact heating water to heat water.
A direct solar hot water system cycles potable water through your collectors where it is heated by the sun and moves throughout your home.
An indirect storage tank is heated through the boiler this requires your boiler to get up to temperature to heat the water properly.
A direct fired water heater can be heated by propane oil or natural gas and has its own burner.
This increases the chance of heat losses in the boiler and associated pipework between the boiler and calorifier.
These types of water heaters are traditionally the most energy efficient.
From a tank the water flows up through solar collectors and back down to.
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.
The system is essentially a closed loop that water flows through.
However indirect heaters are more efficient in other ways.
Standard direct water heaters don t need to transport water over a distance so in one regard they can be seen as more efficient.