Solar Hot Water Systems are Solar Heaters used across the around the world for nearly every water heating application imaginable. Whether your application is residential, commercial, industrial, municipal or agricultural, Solar Hot Water Systems are designed for Domestic Hot Water production, Radiant Floor and Space Heating, and Solar Pool and Spa/Hot Tub Heating.
How does Solar Hot Water Differ from PV or Solar Electricity? PV, or Solar Electric, uses the energy trapped within sunlight to generate an electrical charge. This charge can then be stored and used to power any number of electronic and electric devices. Solar Hot Water, however, is also known as Solar Thermal, and used the tremendous energy trapped within sunlight to generate heat – this heat is then transferred by any number of mechanisms to water. We can use that water for nearly every hot water application – from domestic hot water use to radiant space heating to pool/spa heating. In, fact, Solar Thermal technology is much further advanced that PV technology today – a typical PV panel has an efficiency of 14 – 20% where a Solar Hot Water System has an efficiency of 80% or better – this makes Solar Heaters one of, if not, the most cost-effective and affordable uses of Solar Energy available today.
Solar Heaters comprise of these components:
- Solar Collectors,
- Water tank,
- Solar Workstation,
- Relief valve,
- Copper Piping and/or PEX Tubing,
- Connections and Other Basic Plumbing Hardware
Popular types of Solar Collectors and their working principles:
Metal Heat Pipe Solar Collector consists of a vacuum tube, a heat pipe, a metal heat absorption wing and the connecting manifold. The metal heat absorption wing with selective absorption coating converts solar energy into heat energy and transfers it medium liquid inside. The vacuum between the two glass tubes works as insulation. The liquid in the heat pipe changes into vapor which rises to the condenser. When passing through the heat exchanger, the heat is absorbed and the temperature is lowed, and the vapor becomes liquid, returns to the base of the heat pipe. This transference of heat is a continuous circulation as long as the collector is heated by the sun.
Vacuum Tubes are absorber part of the Solar Heaters, consisting of double-layer coaxial glass tubes coated from inside with absorber selective material. This coating absorbs solar energy and converts it into thermal energy for water heating. Evacuated Tube Solar Collectors – it allows for great absorption earlier and later in the day when the sun is at odd angles for most solar collectors – leading to increased overall system efficiency and cost-effectiveness. The solar radiation then heats the copper heat pipe within the Evacuated Tube, which transfers its heat upward where it is passed to the water moving through the manifold through the specially designed condenser.
Evacuated Tubes convert solar energy into heat energy, that is transferred to U pipe by an aluminum fin with high solar energy absorption and low heat radiance loss, Liquid (antifreezing liquid or water) in the U pipe heats up, and the U pipe conducts thermal energy to the water inside the storage tank directly (or through internal copper coil). U-Type Solar Collectors are a form of Evacuated Tube Solar Collector. The main difference is that where the standard evacuated tube solar collector has straight heat pipes with a condenser bulb at the top for heat transfer, U-Pipe Heat Pipes are exactly that – a U-Shaped Pipe that sends cold HTF (Heat Transfer Fluid) down one side – it is then heated within the evacuated tube – and then transferred back to the manifold up the other side of the pipe.
Flat Plate solar collector is a metal box with a glass cover (called glazing) on top and a colored absorber plate at the middle. The sides and bottom of the collector are usually insulated to minimize heat loss. Sunlight passes through the glazing and strikes the absorber plate, which heats up, changing solar energy into heat energy. The heat is transferred to liquid passing through pipes attached to the absorber plate. They are designed much like a PV panel, with a flat surface, however, they are much deeper, and inside each collector are a series of copper tubes. As water passes through the collector it is heated by the available solar radiation for use in whatever application your Solar Hot Water System is being used.
Note: Non-pressure are not actually solar collectors – they are actually a complete Solar Hot Water System. Non-pressure Solar Hot Water System includes a direct flow Evacuated Tube Solar Collector – water is heated directly within the evacuated tube (not indirectly through a heat pipe and condensor) and an integrated Solar Hot Water Storage Tank mounted directly to the top of the solar collector, where the manifold would be on a traditional Evacuated Tube Solar Collector. Non-pressure Systems are closed loop – the potable water in the storage tank is separated from the HTF by a Heat Exchanger, which allows for the use of Glycol – this revolutionary step forward allows.