How does water quality affect performance?

Water-cooled chillers rely on the condenser water loop to transfer heat from the refrigerant to cooling tower water. If the water contains excessive minerals, corrosive ions, or biological contaminants, the heat-exchange surfaces inside the condenser tubes and other components will deteriorate rapidly, resulting in higher condensing temperatures, increased power consumption, and shortened equipment lifespan. The three primary water-quality issues affecting system performance are scale, corrosion, and biological fouling.

Scale occurs when minerals such as calcium, magnesium, and silica precipitate from hard water and deposit onto condenser tube walls. Even a thin 1 mm layer of scale can reduce heat-transfer efficiency by more than 10%. As scale accumulates, the condenser’s thermal resistance increases, forcing the compressor to work harder to achieve the same cooling capacity.

Effects of scale buildup include:

Higher condensing pressure

Increased energy consumption

Reduced cooling capacity

Increased compressor load and wear

Aurashu chillers are engineered with high-efficiency heat exchangers, but scale accumulation can still drastically degrade performance if water quality is not controlled. Proper use of softening treatments, anti-scaling chemicals, and regular tube brushing is essential.

Unbalanced water chemistry (low pH, high dissolved oxygen, high chloride content) can accelerate internal corrosion of pipes, condenser tubes, and metal components. Corrosion can cause pitting, leakage, tube failures, and circulating debris that further damages pumps and valves.

Consequences of corrosion include:

Tube wall thinning and rupture

Water-side leaks requiring shutdown

Higher maintenance and repair costs

Contaminants spreading through the system

Aurashu systems use corrosion-resistant materials, but proper water treatment (pH control, oxygen reduction, corrosion inhibitors) remains essential for long-term stability.

Warm condenser water provides an environment where bacteria, algae, and biofilm grow rapidly, especially in cooling towers. Biofilm can be up to 4 times more insulating than mineral scale, making it one of the most harmful contaminants to chiller performance.

Effects include:

Reduced flow rate

Blocked condenser tubes

Increased condensing temperature and energy consumption

Higher risk of microbiological contamination

Aurashu systems support compatible chemical-injection interfaces for biocide dosing, filtration, and online cleaning systems to minimize fouling risk.

If water quality is not properly controlled, the system may encounter:

Reduced heat-transfer efficiency

10–30% higher energy consumption

More frequent system alarms and shutdowns

Shortened compressor and heat-exchanger lifespan

Increased annual O&M costs

Aurashu’s high-efficiency centrifugal chillers operate at extremely low pressure ratios, meaning even small increases in condensing temperature significantly impact performance. Therefore, water quality directly determines whether the system can maintain its optimal design efficiency.

To ensure stable performance, Aurashu recommends the following water-treatment strategy:

Biocide dosing (alternating oxidizing and non-oxidizing)

With proper water management, Aurashu chillers maintain long-lasting, high-efficiency performance, reduced operating costs, and extended equipment lifespan.