HVAC Tower Efficiency
If Air conditioning is one of our nations largest energy drain then large building chiller systems often with evaporative cooling towers make up a large part of that statistic. These systems are often the largest most expensive building system and use a lot of power to deliver a comfortable environment. Although built to last for many years these systems become far less effective as they age. This loss of efficiency comes primarily from corrosion and the buildup of scale, chemicals and biomass in the heat exchanger. Very simply the expensive system will need to run twice as much to provide the same cool air. Part of the problem is that large amounts of chemicals are added to the critically important closed water loop part of the system to prevent biological buildup. Chemicals over time will cause their own buildup and contribute to the detrition of the waters ability to cool. To make matters worse, these systems contain an important sensor that will initiate system water exchanges called blow-down when they detect too much contaminant, mineral particles or certain chemical elements. If not properly managed the blow-down on a chiller system can exceed a million gallons per year.
The good news is, that millions of gallons of waste water and the steady loss of chiller efficiency can be greatly reduced with advancing chemistry. The importance of this closed loop chiller water as well as the refrigerant oil should not be understated. It is the lifeblood of the equipment and should be treated as such. In fact a quality chiller efficiency consultant will send a small sample of the system water and refrigerant lubricating oil into an equipt testing facility to study the condition and component compounds. Similar to a blood test, the consultant along with the retrofit solution manufacturers may notice system concerns and will use the analysis to determine best practice.
Chiller technology continues to advance and a new combination of technologies can be custom designed that will improve the quality of the chiller water and heat exchange. These systems will maintain optimal chiller water chemistry, allowing for a reduction of harmful chemicals and reduced scaling, corrosion and bio buildup in the heat exchanger. The centerpiece of this process is called a Electrolytic Bromine Generator which is able to increase system efficiency and prevent most of the blow-down of used chiller water.
The electrolytic bromine delivered in a sidestream flow of highly cycled cooling tower water by electrochemical oxidation of the chloride and bromide ions present. Electrolytic bromine is an excellent standalone biocide for the alkaline pH conditions common to such cooling waters. Operated on an intermittent basis, with dosage frequency dependent upon the specific degree of biological control desired, the produced electrolytic bromine converts back to bromide ion and is continuously recycled through the unit many times, thus eliminating any need to add dangerous, toxic chemical biocides to the cooling tower. Note that the technology can only be used on cooling tower systems using 100% softened makeup water and which are cycled to a minimum conductivity of 4,000 mmhos. Biocide dose frequency and length is controlled via an external timer unit or controller, sufficient bromide ion is provided by recommended water chemistry dealers. This unit can treat cooling systems ranging from 100 gallons to as high as 100,000 gallons and will often be partnered with water softening, filtration, wetting agents and corrosion inhibitors, to maximize efficiency and minimize water waste, and metal fatigue.