Product Description: Thanks to its special thermal heat pipe inside vacuum tube for heat transfer, the heater can dispense with the water feeding into the vacuum tube, and has the following advantages, such as big power, high efficiency, long service life, fast start, and outstanding resistance to freeze and temperature strain. This kind of water heater features excellent thermal characteristics(heat-exchange rate up to 55% or above even in winter), high operating temperature, all-weather application, and high reliability(in good working order even at -50c). For heat pipe tube: --degree of vacuum: >5x10-3 pa --coating: Aluminium nitride --absorption coefficient: >0.93 --emissivity: <0.08 --starting temperature: <25 c --max. Temperature:250 c --freeze-proof: -50 c --service life: >15 years --wind resistance:30m/s(grade 11) --hail proof:35mm --glass material: Concentrated borosilicate glass --absorber plate: Copper profile --size of single tube:(mm)47x1500,58x1500 --weight of single tube:1.5kg/2.0kg --size of condenser end:(mm) 14x50 --heating-up coefficient: >95% Standard met: Iso9001