Unfortunately our new outdoor AC unit – a usual with a fan and aluminium heat exchanger – does not contain plugs to a water heat exchanger.
That's a pity as the waste heat in summer could be used to heat a pool or perhaps water for showering too.
I found online some commercial setups that plug between the compressor? and heat exchanger, but 1) the AC unit probably does not have easy access to this pipe and 2) the total cost is way too steep (around 10x the pvc pool cost).
I calculated that for a 20 tonne pool a modest AC usage could heat it up around 3° Celsius every day.
The solution must not involve modifying the coolant line as the cost would be too high.
So pretty much that results in spraying or pouring water in the unit on the aluminium blades. Probably not the chlorinated pool water but a normal water that would form some kind of primary circuit which would interface in a heat exchanger with the pool water.
But I have two questions.
How much water the AC unit can safely tolerate. (It should perfectly withstand heavy rains, right?)
Will the water heat up, or rather just evaporate? (Thus not actually heating up the water.) That probably depends on the amount of water sprayed/poured on the system.