Condensor for extract fan.

I've not come across one as otherwise I wouldn't be asking:

A condensor / condensation trap for a bathroom extract fan.
I've fitted condensation traps in long runs of ducting to get rid of water, but they're just outlets at the lowest point of the duct to run off, and the duct still vents the extracted air outside...
What I'm after is a something along the likes of a condensing tumble drier; ie no need to vent the air outside.

I imagine maybe something like the aftermarket box for tumble driers that you have to empty, but with a run-off to a waste pipe instead of having to empty.

Reason is it's impossible to vent outside within financial reason, but there is a waste pipe it could go into.

***I might have just answered my own question - but does anyone know of any ACME™ solutions?***

Cheers.

 

I may actually be able to answer my own question, but like most regs it's arguable (I have argued a few with LABC and they have keeled over to the voice of reason).

Not permitted: All 'stale air' has to be vented externally. Building Regs Part F, 4.6/4,7.

Venting the dehumidifed 'stale air' to a cold-roof loft space with obviously adequate trickle ventilation could be argued as OK. I'll phone LABC and find out.

The problem is bungaroosh walls and 4th floor. Core drills don't work in bungaroosh and scaffold needed to make good a chiselled hole on the outside wall. Or scaffold and a roofer for a tile vent.

 

Not heard of that one. Got a posh project that's just been pencilled in and the kitchen's in the middle of the house. Sounds good.