Finned isolation tube for solar collector - comprises bimetallic tube of copper outside and aluminium inside with aluminium fins, reducing fabrication cost

摘要

A finned tube for exposure to radiation in a solar energy collector comprises a bimetal tube of Cu inside and Al outside fitted with fins in thin Al sheet welded in the shape of a fan on the outer part of the bimetal tube. Each end of the bimetal tube is pref. left free of its Al part, which is replaced by a copper sleeve welded by induction. Making the fins of Al instead of the more expensive Cu reduces the cost of fabrication.