Ian Stirling wrote:
wrote:

Or the OP could buy ?90 worth of hosepipe, polythene & pump, and get
10kW with 1/10th the run cost of the 3kW heater.

Not a tough choice. Cheap pool solar heating is very easy to make btw,
probably easier than installing electric into the water.

Details?
10m^2 collector area, how does it work?
Polythene over hosepipe?


ok... firstly I would not use an open roof surface for collection, as
a) it will also collect bird**** and other assorted bacteria
b) it will leak water onto the roof structure underneath the covering
and rot it.

Buy a =A350 pump, checking it can run continuously and has a type of
motor that can be slowed down eaily.

Spend the rest of the money on hosepipe, the more the better. Avoid
orange, white or light grey. Wind it in a huge flat spiral pancake.
You'll get a lot more heat if you space each turn out by one pipe
width, but that requires wire or similar to hold it togther/apart. Aim
for 10 square metres or more.

Cover the pipe with polythene, add the pump on an RCD, and run it at
lowest speed setting.

You now have a fairly efficient low cost 10kW heater.


NT