Abstract: A solar collector has a polygonal top panel forming a top face and having at least three edges, a similarly polygonal bottom panel forming a bottom face directed away from the top face and fitted congruently to the top panel to form a flow passage extending between the faces, and at least four connectors projecting from at least three of the edges.

Abstract: A carrier liquid for agent concentrates which are added to polymerizates that are suitable for melt spinning is proposed, the carrier liquid comprising three components, namely a) a base oil as main constituent having a thermostability of more than 300° C.; b) at least one antioxidant acting as a radical trap; and c) at least one compound which deactivates catalysts for the polymerization of fiber-forming materials that are suitable for melt spinning. The carrier liquid is used for the production of an agent concentrate which contains color pigments, bactericides and/or fungicides for polymerizates that are suitable for melt spinning. The agent concentrates are used for spin dyeing textile fibers and technical fibers, particularly partially oriented yarns.