Cooling Towers
Cooling Towers are used to reject heat from air conditioning systems. In a cooling tower, a circulating stream of warm water contact an air flow, causing evaporation of a portion of the water. When this water evaporates, the water which remains behind is cooled. The cooled water then circulates through a cooling system, warms, and then returns to the tower.

• Understand Your System: Prepare an inventory of each cooling tower you have, its cooling capacity, and the equipment or processes that it serves.

• If you purchase chemicals for the treatment of the recirculating cooling tower water, have the chemical vendor explain the purpose and action of each chemical.

• Have your chemical vendor provide a written report of each service call, and be sure that the vendor explains the meaning of each analysis performed, as well as the test results.

• Tell your chemical vendor that water conservation is a priority, and ask about alternatives that may reduce the amount of water bled-off from the towers.

• Have vendors bid for your facility's water cooling tower water treatment. Require a predetermined minimum level of water efficiency. Have them provide figures showing projected annual water and chemical consumption and costs.

• Consider incorporating sulfuric acid to reduce carbonate scale and achieve significantly higher cycles of concentration. If you use sulfuric acid, be sure to observe appropriate safety precautions.

• Ozone is another alternative that can help remove dissolved minerals and act as a biocide. Again, observe the appropriate safety precautions.

• If available, use reclaimed water as a source of cooling tower make-up water.

• Blow-down water is the release of some of the circulating water to remove suspended and dissolved solids left behind as pure water evaporates from the system. Re-use blow down where possible for non-potable uses.

Evaporative Coolers
Evaporative coolers lower air temperature by increasing the humidity of incoming air being drawn into a building. The air's ambient or "dry bulb" temperature is lowered when the air absorbs water vapor. After a short period of operation, the recirculating air in the cooler reaches wet bulb temperature, which is theoretically the lowest temperature to which the entering air may be cooled. Some evaporative coolers have recirculation pumps.

All evaporative coolers require either a small amount of bleed-off or regular cleaning to maintain and prevent damage to the cooler's pads. The principle opportunity for conservation in evaporative cooling is to reduce the amount of water bled-off, and to reuse that water wherever possible.

• Be sure your coolers have pumps to recirculate the water. This decreases water consumption and increases cooling efficiency.

• Check to make sure you are not bleeding off an excessive amount of water. For a typical small cooler, anything more than a few gallons per hour may be excessive.

• Pipe the bleed-off water from your coolers to help water a landscaped area!

• Replace single-pass cooling models with air-cooled or recirculating models.

• Connect to a recirculating cooling water loop. Or retrofit models to be recirculating.

• If a piece of equipment cannot be replaced immediately, remember, it is illegal to dump single pass cooling water into the sewer system. Re-use this water for landscaping or other non-potable uses.

• Replace toilets with Ultra Low Flush Models, or retrofit with low flow flappers. Contact the Maui County Board of Water Supply at 270-7199 or the Wastewater Division at 270-7417 for more information.

• Retrofit faucets with aerators, or consider alternative faucet types such as self-closing or automatic sensor controlled faucets.

• Replace showerheads with low flow models. Contact the Maui County Board of Water Supply at 270-7199, or the Public Works Wastewater Division at 270-7417 to find out how you can get these! (Or fill out the Low Flow Fixture Data Form and return it to DWS.)

• Check for leaks! Check for leaks! Check for leaks! Do dye tablet or food coloring tests in toilets to check for hidden leaks. Check for dripping faucets indoors and out!

• Efficient washing machines can save up to 20 gallons per load. These also save on energy. If you are replacing laundry facilities, don't even consider anything but the new horizontal axis models. These not only save up to 40% of water used, but deliver even more substantial energy savings -- up to 65%!

• Water boilers also require blow-down, or bleed-off, just like air conditioners. Monitor total dissolved solids, and blow down only when necessary!

• Avoid excessive filter or softener back flush. Back flush only when needed.

• Never hose your sidewalks and driveways. This is a complete waste of water, and a hose can use 25 gallons in just 5 minutes. Remember: A broom is best.

• Check for leaks! Note the number of outdoor faucets on the outsides of buildings. Make a list and check every one regularly.

• Cover pools and jacuzzis when not in use. An average sized pool loses about 1,000 gallons per day. A pool cover can cut these losses by 90%.

• Knowledge is power. Educate people about how they can help to save water at your building or facility. You may be surprised at how willing people are to chip in, once they know what to do!

• Understand your system: Develop a schematic of all water entry points. Know where your faucets, time clocks, solenoids, booster pumps, sprinklers, bubblers, valves, pipes, etc. are located.

• Make a checklist of system elements and check each one regularly for leaks! Finding and repairing leaks can lead to big savings, especially in irrigation systems!

• Use turf only where actually necessary. Avoid turf except in picnic or active play areas.

• Choose the right plants. Native plants appropriate for your region are best. These save water, because they are adapted to survive on the natural rainfall of the area. Besides saving water, they also help to avoid the spread of invasive alien plant species which can destroy native ecosystems. And they contribute to the true Hawaiian sense of place.

• Avoid over-watering! Use soil moisture over-rides and rain-shutoffs on all automated systems. Reset controllers at least once per month to account for changing evapotranspiration.

• Zone your plants. This means that plants with similar water needs should be grouped together. This avoids wasting water, over-watering some plants, and under-watering others.

• Never water during the heat of the day. The best time to water is just around sunrise. Evenings are also acceptable. Once the sun comes up, the evapotranspiration rate soars, and much of your water is wasted.

• Having your soil tested also helps you to learn what type of watering is needed. Clay soils take from ¼ to ½" of water per hour before water starts running off and being wasted. Sandy soils require somewhat more frequent, shorter watering.

• Mulch, compost, or other organic material will help soils hold moisture, keep the ground from overheating, and discourage weeds. Loosening the soil while you add the organic matter will also help keep your lawn healthier.

• Root feeder or water aerator probes around trees and bushes will help to direct water where it is needed. You can also build a watering basin in the soil around the base of your plants to help the water soak in deeply.