Due to possible accessibilty issues, I'm thinking of installing water cooled air-conditioning to avoid an external condenser.
Does anyone have any experience of this both in terms of the installation and running costs.
TIA

Do you mean a portable A/C unit?
I bought this one. It was pretty ineffective and made a horrendous noise.

Errr... I don't know much about water cooled air conditioning... I dont know why you specify water, and I am interested in why.

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But if your requirement is to cool your room without an external unit.... there are many AC's out there... Portable, as Missile says, and have a largish pipe that you put outdoors. You often get window/door kits that you use to block the gap above the pipe (or on the side) ... That "seals the gap" from the outside heat.

They usually have wheels and you can move them to any room you are in.

The problem is the noise .. which a normal unit makes outside, of course.

But you can google silent, or quiet units (I did it recently) and can pick a model for you. Some have a 'night mode' and (apparently) will get the sound to +/- 50db.

I know so little about water cooling, but the big problem is humidity... Its the 'killer' when combined with heat (or cold), especially if it's already hot and humid. Im guessing that water cooling also increases the humidity

Every normal (non water,) ac takes water out of the humid air... Decreasing the rooms humidity.... A major benefit for me.

With the portable ac I mentioned above, there is a second small pipe you attach to take that water out... ( There is often a drawer inside, but in a humid place, it fills up quickly... And when full the unit senses it and switches off).. I go for the separate pipe, into a bucket inside.. or better one outside... Or into your garden

The water is pretty distilled, and ok for eg ironing....

Good luck

Jon

We used to install “water cooled” units in shopping centres, I presume you mean to cool the hot gasses in the condenser, it would not be cost effective for a domestic unit as you would need a steady supply of cool water passing through the “condenser” which would be an expensive waste of water or as the shopping centres do they have a piped ring main of water through the entire building which is recirculated but it does have to pass through a water chiller or some form of outdoor heat exchanger to give up the heat created by the hot gasses, the disadvantages of this type of system is the indoor units are much bigger than you would normally see and as it contains the compressor it can be noisy, not quite like a normal split system air conditioner.

I presume you have a problem with obtaining permission to site an outdoor unit, if you can’t disguise it to hide it your options are a portable unit which consists of an indoor unit, an outdoor unit and flexible pipes which carry the refrigerant, and can quickly be removed when needed without dismantling anything or you could get a self contained evaporative air conditioner, not as good as a refrigerated system but it will reduce the temperature of the room.