How does solar hot water work?

Solar hot water systems are being used worldwide to heat water for domestic use. This style of water heater uses solar energy to capture sunlight and heat the water. Not only is it a good way to reduce your electricity bills but it also reduces our need for conventional hot water systems.

Let us discuss the types and different components of solar hot water systems and how they work.

Types of solar hot water systems

  • Direct vs Indirect – In the direct system – the water is heated directly by the sun. The indirect system – solar energy is trapped using an anti-freeze fluid. This fluid heats up the water.
  • Active vs passive solar hot water systems – Active solar hot water systems use controllers to pump water or anti-freeze fluid through the hot water system. In passive solar hot water systems, gravity is used to circulate the water.
  • Close coupled solar HW vs Open coupled (split system) solar HW – In close-coupled systems, the solar hot water system is located on the roof, and the storage tank is located above the collectors. The water is heated using the principle of thermosiphon, i.e., the collectors absorb sunlight and heat up the water. The hot water flows to the storage tank and cold water remains in the collector to get heated. It requires less maintenance as it doesn’t have a pump.
    In the split system, the tank is located on the ground and the remaining parts are on the roof. A pump is used to send the water to the collectors to be heated and then back to the storage tank. If your roof has ample space, a close-coupled system is ideal, otherwise, a split system offers a viable solution.

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Components of solar hot-water systems

The main components of solar hot-water systems include:

  • Collectors – The collectors capture sunlight and convert it into heat energy. The collectors need to face the north to capture maximum sunlight throughout the day. Also, they need minimum shade as they won’t be able to work efficiently if they are getting blocked by trees or other buildings. There are two types of collectors – Flat Plate collectors and Evacuated Tube collectors.
    • Flat Plate Collectors – these are made of an aluminium box covered with a glass lid. The copper pipes are placed inside the aluminium box. They are the cheaper option and are easy to manufacture but have lower efficiency.
    • Evacuated Tube Collectors – work on the principle of trapping sunlight. These collectors consist of copper pipes also known as heat pipes fused between glass tubes. As there is space between the two glass tubes, it creates a vacuum preventing heat loss. The evacuated tubes are more efficient at heating the water than flat plate collectors. They can capture more sunlight due to their higher surface area, don’t need direct sunlight, and can work effectively in low temperatures. It is easy to replace the glass tubes in case of any damage and they are more durable.
  • Heat Exchanger – It is used to transfer the heat from the collector to the storage tank.
  • Control System – Includes thermometer, thermostat, pump, pressure gauge, flowmeter, and valve. The valve is used to shut off the cold water supply to your hot water tank.
  • Backup Heater – Backup heater is used for heating the water using electricity or gas to ensure a reliable supply of hot water even on very overcast days or throughout the night.
  • Storage Tank – Used to store water from the collector.

Solar Hot Water System Specialists

Switch to solar water heating today and save money on your household bills. Fallon Solutions provides the best solar water systems contact our friendly team at 1300 762 260 for more information.