GTC M series GLASS TUBE
M series vacuum tube are used in non-pressure type solar water heater,low pressure system,more information please contact with gtc solar.
GTC’s vacuum tube adopt dry absorb type selective coating with lower remittance,
it solved the problem of normal tube having not good curve of remittance.Higher Efficency:The absorbance increased by 14% with remittance reduce by 30-40%
tempreture can reach higher and anti-freezing at -30°C environment temperature and still working
Higher Vacuum Degree:Unique technology to keep the vacuum degree,stable absorbance which guarantee the long life of the tube

| zhejiang green technologe solar vucuum tube spec. | |||
| model name | M series high efficiency tubes | T series high efficiency tubes | |
| Structure | All-glass concentric dual tube geometer | ||
| Glass material | Borosilicate glass | ||
| Outer tube diameter and thickness | Ø47±0.7mm &=1.5mm | ||
| Ø58±0.7mm &= 2.0 mm | |||
| Inner tube diameter and thickness | Ø37±0.7mm &=1.5mm | ||
| Ø47±0.7mm &=1.6mm | |||
| Tube Length | 1500(±5mm) | ||
| 1800( ±5mm) | |||
| Absorbing coating properties | Construction | Graded Al-N/Al solar selective absorbing coating | graded SS-C/CU solar selective absorbing coating |
| Method to deposition | DC reactive sputtering | 3 sputtering | |
| Absorbance | >91% | >94% | |
| Emittance | <8%(80°C) | <6% | |
| Vacuum | P<5X10 -3 Pa | ||
| Stagnation parameter | = 230M 2 °C/KW | 260m2 C/kw | |
| Solar radiance exposure for obtaining a preset water temperature | = 2.8MJ/M 2 | ||
| Average heat loss coefficient | 0.8w/m2 C | 0.6W/(m2 C | |