solar water heater vacuum tube

soalr water heater vacuum tube: 3.3high borosilicate glass The vacuum tube of our solar water heater has the high absorption rate and low emission rate, the absorption rate is 0.90-0.93 (AM1.5) the emission rate is 0.05-0.075 (80±5) vacuum tightness is P≤5.0*0.0001Pa idle sunning property parameters is Y=220-260./KW the average heat loss coefficient is Ult=0.6-0.7W(.) This makes the vacuum tubes highly absorptive and highly durable to high temperature and low temperature. Meanwhile the vacuum tube features a low reflection ratio. It means the temperature in the water tank is range from 50 to 95.