Achieving conservation excellence is mainly dependant on an intelligent control system, especially for multiple unit installations. Our

controls all parallel in one cooling loop installed hybrid dry coolers in a very efficient way. Algorithms are configured to maximize the operation time in dry mode, thus saving a maximum amount of water.
Remember, especially for AC installations the IPLV standard is weighting the 100% load point only with 1%, means a chiller is operating throughout the year with 100% load only to 1% of it`s operating time. Major operation time due to chiller load is around 75% and 50% while these points are weighted with 42% resp. 45%. See table sheet below:

IPLV definition 1998 standard
%Load	WC ECWT °F	AC EDB °F	EC EWB °F	Weighting
100%	85	95	75.00	1%
75%	75	80	68.75	42%
50%	65	65	62.50	45%
25%	65	55	56.25	12%

Lower outside air temperatures in combination with chiller part load operation is potentially leading to an oversized heat exchanger surface area while operating multiple coolers steadily without shutting them down. The oversized surface area in accordance to the actual chiller partload condition on the other hand reduces drastically the need for wettening the heat exchanger coils, consequently reducing the fresh water consumption.
Therefore all wetting pumps are shut off during low load conditions. If load increases, the fan speed of all fans at all installed coolers will be adjusted in accordance to the load, finally up to 100% fan speed.

If the required cooling load exceeds this capacity, just one wetting pump will be activated to meet the total system load. While the effect of wetting a coil is huge, the fan rpm at this cooler will be reduced, while all other coolers in dry mode still operate at maximum fan speed.
Any additional load impact only leads to an increased fan speed at the cooler operating in wet mode without the need to activate additional wetting pumps.

If the required cooling load continues to raise, the next wetting pump will be activated in the same way as described, and so on until 100% total cooling tower load are achieved.

Keeping coils intelligently dry is saving water and operating cost.
Water is precious, use it wisely!