WE Credit: Cooling Tower Water Use

Reuse water as many times as possible → then supplement with alternative sources

Why This Credit Matters

Cooling towers are one of the largest water consumers in commercial buildings.

👉 LEED focuses on:

Using water efficiently in cooling systems while maintaining system health

⚙️ Key Concept First (VERY IMPORTANT)

💡 What is Makeup Water?

👉 Makeup water = water added to replace:

• evaporation
• blowdown (bleed-off)
• drift losses

💡 What are Cycles of Concentration?

👉 Cycles = how many times water is reused before discharge

• Higher cycles → less water waste
• Lower cycles → more water wasted

🧠 Simple Understanding:

• 5 cycles → water reused 5 times
• 10 cycles → water reused 10 times

👉 More cycles = better efficiency

🧩 Credit Overview

Intent

👉 Reduce cooling tower water use

👉 While controlling:

• scale
• corrosion
• biological growth

📏 Step 1: Water Quality Analysis (MANDATORY)

Projects must perform a one-time potable water analysis

🔬 Measure ALL 5 parameters:

• Calcium (Ca as CaCO₃)
• Total Alkalinity
• Silica (SiO₂)
• Chlorine (Cl)
• Conductivity

⚠️ Exam Tip:

👉 You don’t need to memorize exact chemistry
👉 But you must know that 5 parameters are required

📏 Step 2: Control Cycles of Concentration

👉 System must be designed so:

None of the parameters exceed maximum limits

🏆 Points Structure

🥇 Option 1: Increase Cycles

• Up to 10 cycles → 1 point
• >10 cycles → 2 points

🥈 Option 2: Combine Efficiency + Nonpotable Water

👉 Earn 2 points if:

• achieve up to 10 cycles
  AND
• use ≥20% nonpotable water

♻️ Nonpotable Water Sources

(from your slide + expanded)

• HVAC condensate
• Steam condensate
• Ice machine condensate
• Rainwater
• Reclaimed water
• Process water

💡 High-Value Strategy

👉 100% nonpotable water (if feasible)
= strong sustainability + easier compliance

🧠 Where People Get Confused

❌ Misconception 1:

“More chemicals = more cycles”

👉 Not necessarily

👉 Cycles depend on:

• water quality
• system design

❌ Misconception 2:

“Nonpotable water alone earns points”

👉 No

👉 Must still meet:

• cycle requirements

❌ Misconception 3:

“10 cycles = maximum”

👉 No

👉 More than 10 cycles = best performance