Water cooling A/C system of air conditioing

記得約十年新聞有報導過

以前因為水務條例不容許用食水作空調冷卻用途(以前香港食水珍貴，供應不穩定，供應穩定後無改例)。海水冷卻要近海才可行。其實以前很多工廠都偷偷用食水作空調冷卻的，你看以前工廠區後巷幾多水塔就知。現在工業北移所以小了。相反商業大廈因外觀問題不可以偷用水塔(水塔最好放天台的方便散熱，不過商業大廈的結構不容許天台放太重的equipment)，用海水冷卻要用很多地方放equipment唔化算。而且海水chiller要經常清理(因海水污髒)，抽水泵用電也不小。

If the clients (government, developers, etc.) do not specify to use a water-cooled A/C system, the contractors, who install the A/C system, will usually prefer an air-cooled A/C system as it is less expensive for the equipment and the installation with an air-cooled A/C system.
For an air-cooled A/C system, the heat released from the refrigeration cycle is usually emitted out of the system with the help of not much more than a number of fans (and/or louvres).
For a water-cooled A/C system, the heat released from the refrigeration cycle is stored in the water, and usually has to be delivered to a cooling tower for evaporation, or discharge heated water into other water bodies (e.g. sea water) and requires not only more space but also more piping and installtion. These add costs to contractors and require more time to install.