1. What is Blowdown Rate Calculation?

Blowdown rate calculation is essential for cooling tower water management to control dissolved solids concentration. It determines the amount of water that must be drained and replaced to maintain optimal water quality and prevent scaling and corrosion.

2. How Does the Calculator Work?

The calculator uses the blowdown rate formula:

Where:

• \( \text{Evaporation Rate} \) — Rate of water evaporation from the cooling tower (GPM)
• \( \text{Concentration Factor} \) — Ratio of dissolved solids in circulating water to makeup water (dimensionless)
• \( \text{Blowdown Rate} \) — Required drainage rate to maintain water quality (GPM)

Explanation: The formula calculates the necessary blowdown rate to maintain the desired concentration factor while accounting for water lost through evaporation.

3. Importance of Blowdown Rate Calculation

Details: Proper blowdown rate calculation is crucial for maintaining cooling tower efficiency, preventing scale formation, controlling corrosion, reducing chemical treatment costs, and ensuring environmental compliance.

4. Using the Calculator

Tips: Enter evaporation rate in gallons per minute (GPM) and concentration factor as a dimensionless number greater than 1. Both values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the purpose of blowdown in cooling towers?
A: Blowdown removes concentrated dissolved solids from the cooling tower system to prevent scaling, corrosion, and biological growth, maintaining system efficiency.

Q2: How is evaporation rate determined?
A: Evaporation rate is typically estimated as 1% of circulating water flow rate for every 10°F temperature drop across the cooling tower.

Q3: What is a typical concentration factor range?
A: Concentration factors typically range from 3 to 7 cycles of concentration, depending on water quality and system requirements.

Q4: What happens if blowdown rate is too low?
A: Insufficient blowdown leads to high dissolved solids concentration, causing scale formation, reduced heat transfer efficiency, and potential equipment damage.

Q5: Can blowdown water be reused?
A: Yes, blowdown water can often be treated and reused for non-critical applications like irrigation or makeup water for other processes, reducing overall water consumption.