... less, warming faster. Efficient tube, the super absorbing, thermal efficiency is high, warming faster, in the same light ... as request. Long time warranty for 15 years. Solar collector technology index Index nameChina national standards (GB/T 17049 ... range of not more than 2, the whole pipe, not more than 2.5 mm in the ... 10mm range of not more than 1, the whole pipe, not more than 5, the stones shall not ...