Solar Evacuated Tubes
The colder Regions Solution

Solar Evacuated Tubes provide the ultimate solar heating water solution to tough winter regions, the northern states of the US and the northern countries of Europe. They are the second generation of the flat panel solar collector, more efficient and cost more.

Evacuated Tubes Construction

Each tube has concentric glass tubes. The internal tube has an absorbing layer on its outer surface (acts like a mirror), the external tube is transparent to light. Two thin pipes inside the inner tube flow colder glycol into it and hotter glycol out of it. There are 20 to 30 tubes in a typical collector. The glycol from the tubes goes in a close loop to the hot water tank heat exchanger to heat up the water

Advantages

• Circular shape collects sun radiation from more angles, not only at noon time but also early in the morning and late in the afternoon
• The vacuum provides excellent heat isolation, as a result most of the heat stays inside
• In case of one tube failure the performance degradation is minimal (graceful degradation) and this one tube can be repaired

Cost

Cost can range from $3,500 to $4,500 for the collector and the tank. Tax Credits can be claimed to reduce the net cost to the buyer

Life Expectancy

Life expectancy between 10 to 20 years is reasonable if the product came from a manufacturer with a good reputation. 10 years original manufacturer warranty is normal