2. Solar Collector Fabrication
2.1 The Heat Exchanger
(Reprinted from B. Deus et al (2004): ZigZag Collector, BABICO and WOT Publications)
2.1.1 Serpentine Bending
The pipe must be shaped into 7 bends and 2 nearly perpendicular ends. A pipe bending set
should be made for the purpose: guidance is given in Appendix 1. Standard bending springs
used by electricians or central heating engineers are reported to be unable to produce a tight
enough bend radius.
The following tools are needed to prepare the pipes:
- A pipe-holding clamp; a pipe-cutter or hacksaw; a thread-cutter; a folding ruler or measuring
rod; a marker (felt pen)
For 1 hot water system 3 absorbers are needed. So we start to prepare 3 pipes at once. Put
the pipes parallel to one side against a wall. Take the shortest pipe as standard and mark all
pipes at the same length. Cut the pipes straight at the indicated length by means of a pipe-
cutter or hacksaw. On the shortened ends we make a half-inch thread by means of a thread-
cutter. Check the screw thread of all pipes at both sides by means of a half-inch socket. If the
socket can be screwed on by hand, it‟s ok. Keep the socket on to protect the thread while
bending the pipe. Mark the middle of each pipe (around the entire pipe.)
Starting the pipe bending
Slip a ½” pipe into the set. The pipe is locked between disk G and block H (see Appendix 1).
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