Vacuum Tube Solar Water Heating Systems
Solar water heaters are a modern and clean way to use solar energy for heating water in most buildings, making use of a free energy source.
Also, it’s an effective and cheap way to supply hot water necessary for daily uses, as it can work in various weather conditions, heating water quickly and efficiently even in cold days.
How Vacuum tube solar water heating systems works
Vacuum tube solar water heating system technology relies on “evacuated tubes”, which absorb solar energy and convert it to thermal energy; to heat water. Each vacuum tube consists of two borosilicate glass tubes, one inside the other. This kind of glass is durable and resistant to breakage.
The outer tube is transparent to allow sunlight to pass through, while the inner tube is coated with a chrome and nickel black layer that absorbs 98% of the sunlight falling on it.
The chrome and nickel black coating is what makes these solar heat collectors better than other collectors in the market; as it changes the shortwave solar radiation to longwave heat radiation which means that you only lose 6% of the sun energy
The two tube ends are fixed together through a “Fusion” process, after vacuuming the air between them under a high temperature. This vacuum results in the presence of an isolation area between the two tubes, which prevents the water thermal energy from escaping.
Vacuuming the air between the two tubes is to preserve the heat that the tubes absorb from solar rays from escaping; to achieve high efficiency even in cold climates.
Vacuum tube solar water heating systems parts
- Evacuated heating tubes: the tubes are placed in a box to protect them, and inside each of them is a flat or curved copper fin attached to a metal heat pipe that works as a high-efficiency solar collector. The heat pipes transfer the heat from the evacuated tubes, up to the manifold.
- Copper manifold: which is an insulated box containing the pair of contoured copper pipes (copper header pipe) with dry connect sockets that the heat pipes plug into; to protect it against corrosion and freezing or high temperatures.
- The solar control system: that controls the flow of water and prevents the formation of ice and frost.
- Safety valve: that ensures the system is not exposed to high pressure when the water temperature is high.
- Insulated metal tubes: that connects the hot water tank to the collectors.
- Insulated hot water tank: to ensure a constant supply of hot water even in cold winter days.
- Water flow pump.
- Mounting Frame
- Reflector
- Extra attachments
Alternatives in the market
- The main solar alternative to the vacuum tube solar water heating systems in the market is the flat panel solar water heater.
- Other alternatives include gas and electric heaters.
Vacuum Tube Solar Water Heating Systems Benefits
The system operates at a much higher temperature than its counterparts, it can be used for:
- solar home heating applications
- solar space heating
- solar process heating
- solar air conditioning
- commercial solar heating applications
- A clean source of energy
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Efficiency at higher Temperature
In climates where the gap between inner and outer temperature levels is large, vacuum tubes systems are the best choice. - Nearly zero heat loss, as 94% of solar energy goes directly and captured in the inner tube.
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The system can be customizable, by unplugging a couple of heat pipes it can be scaled down
This can be useful in summer where hot water is not needed less, so scaling down the heat output without affecting the system performance.
Maintenance
It’s recommended to keep the collectors clean to effectively absorb thermal energy and to get professional maintaining service once every five years.