* Structure of SOLAR WATER HEATER of Sonha including :
a- 3 layers insulation tank :
  -The cover is SUS 304(TDN GOLD) & color plated steel (TDN ECO) use for food, super durable.
  -Composite insulation layer keeps heat.
  + coefficient of thermal conductivity < 0,017 kw/mk.
  + heat resistance 160º C
  + Maintain the temperature of water for long periods, take the heat overnight 5ºC ÷ 6 ° C

-  The core layer is SUS 304
b- Vacuum heat absorbed tube : Composed of two layers with high impact resistance, in between the vacuum .The surface of tube body inside specially coated metal film consists of  3 layers:
+  Resistant radiator coefficient <0.06%.
+ Heat absorption layer coefficient > 93 %.
+ Transmission layer absorbs thermal and heat inside water.

 -> Achieve ≈ 80°C when the outdoor temperature is 35°C with sunshine.