Solar Keymark Solar Collector Re Ba E series is solar collcetor with thickest warmth-preservation layer which could resist pretty cold clinmate.

Inlet water hole connects to the tap water, and the outlet hole connects to the tap water, and the outlet hole produces pressure hot water directly 5)Efficiency: The advantage of solar tubes is that insulate the inner tube from heat loss. This means that once heat is absorbed, it is transferred to the water in the manifold, and not lost to the outside environment. This is the key difference between solar tubes and flat plate solar collectors: The insulative properties. Combined with heat transfer efficiency of the heat pipe, the collector can deliver excellent heat output all year round.