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ProMoss Delivers Water & Energy Savings in Data Centre Cooling Towers

A clear stream flows gently over rocks covered in green moss, surrounded by lush trees and dense forest vegetation, creating a tranquil scene reminiscent of nature’s way of lowering energy costs through natural cooling and shade.

Overview

A large North American data centre conducted a 14-month side-by-side trial of ProMoss, a plant-based water treatment, against a conventional chemical program. Two identical 1,250-ton centrifugal chiller/cooling tower systems operated in tandem, one treated chemically and the other with ProMoss.

Objective

• Reduce bleed-off water consumption
• Maintain excellent corrosion protection
• Control microbiological activity
• Demonstrate energy efficiency improvements

Large industrial cooling units with metal pipes and railings are installed on a rooftop under a clear blue sky. Elevated on platforms with access stairs, these systems play a key role in lowering energy costs for the facility.

Solution

ProMoss is derived from sphagnum moss and naturally removes hardness ions, metals, and organic binders that drive scale and fouling. Treatment was delivered via feed cages in the tower sump, requiring no other system modifications.
Unlike chemical programs that depend on phosphonates and azoles, ProMoss eliminates hazardous chemistry, reduces maintenance, and supports zero-waste initiatives (spent moss can be reused as mulch or absorbent).

A person holds a large clump of bright green and yellowish-orange moss or lichen outdoors, with blurred vegetation in the background—highlighting nature’s potential role in lowering energy costs.

Results

1. Water Savings
• Cycles of concentration: Chemical system 7.0 → ProMoss system 12.0
• Bleed-off water reduced by 45%, saving ~447,000 gallons (1,691 m³) annually

2. Energy Savings
• Based on the observed 2–3 °F approach reduction, the ProMoss™ system delivered an estimated 2–6% reduction in compressor energy consumption.
Rule of thumb: every 1 °F decrease in approach ≈ 1–2% chiller kWh savings.
• Condenser approach temperature on the ProMoss system declined steadily during the 14-month trial, while the chemically treated system stayed flat.
• Visual inspection confirmed clean condenser tubes with no biofilm.

3. Corrosion Control
• Mild steel: Excellent in both systems (~0.2–1.0 mils/year)
• Copper: Improved from Good (chemical, ~0.3 mils/year) to Excellent (ProMoss™, ~0.1 mils/year)

Line graph titled Chiller Approaches showing PM Chiller and Chem Chiller condenser approach temperatures from 4/5/21 to 12/7/22, with trend lines for each chiller, highlighting the impact on lowering energy costs over time.

Additional Benefits

• No hazardous chemical storage/handling required
• Eliminated chemical feed/storage systems → fewer failure points
• Materials are able to be repurposed: spent moss can be reused as mulch or absorbent
• Eco-friendly blowdown: can be reused for irrigation since no regulated chemicals present

Conclusion

The ProMoss program demonstrated that natural moss-based treatment can outperform conventional chemicals:

• 45% less bleed-off water
• 2–6% chiller energy savings via reduced approach temperature
• Excellent corrosion control (mild steel & copper)

For this data centre, ProMoss delivered a sustainable, safe, and effective water treatment program that aligned operational performance with environmental goals.

Contact us today for a complimentary cooling system assessment to see how ProMoss can reduce water use and energy costs in your facility.