Cooling Tower Results
Results update after calculation and during supported live changes.
Project: Cooling Tower Study
Equipment: CT-001
Design checks
- Calculated cell flow is below the entered minimum.
Performance indicators
Fan intensity: 0.0260 kW/CT ton.
Pump intensity: 0.0869 kW per m³/h.
Water intensity: 2.0025 L/kWh rejected.
Design Inputs
Enter known conditions, select methods, then calculate.
Interactive Performance Charts
Heat Load Versus Water Flow
Capacity Versus Cooling Range
Makeup Water Versus Concentration Cycles
Annual Water-Use Breakdown
Fan Power Versus Airflow
Annual Operating-Cost Breakdown
Scenario Comparison
Compare wet-bulb, range, approach, cycles, and safety margins.
| Scenario | Wet bulb, °C | Range, °C | Approach, °C | Cycles | Margin, % | Capacity, CT tons | Makeup, m³/h |
|---|---|---|---|---|---|---|---|
| Base | — | — | |||||
| Hot day | — | — | |||||
| Water saving | — | — | |||||
| Close approach | — | — |
Formula Used
Cooling Range = Hot-Water Temperature − Cold-Water TemperatureCooling Approach = Cold-Water Temperature − Entering Wet-Bulb TemperatureHeat Load = Mass Flow × Specific Heat × Cooling RangeTower Effectiveness = Range ÷ (Range + Approach) × 100Blowdown = Evaporation ÷ (Cycles − 1) − DriftMakeup Water = Evaporation + Drift + Blowdown + Other LossesPump Power = Density × Gravity × Flow × Head ÷ Combined EfficiencyFan Power = Airflow × Static Pressure ÷ Combined EfficiencyHow to Use This Calculator
- Select the main calculation mode.
- Choose an application preset.
- Enter hot and cold water temperatures.
- Enter the design wet-bulb condition.
- Provide water flow or known heat load.
- Set safety and derating allowances.
- Choose evaporation and concentration methods.
- Enter fan and hydraulic assumptions.
- Add local water and electricity prices.
- Review capacity, losses, costs, and warnings.
- Export the calculation for project records.
Example Data Table
| Application | Hot Water | Cold Water | Wet Bulb | Flow | Typical Range | Typical Approach |
|---|---|---|---|---|---|---|
| HVAC plant | 37°C | 30°C | 25°C | 450 m³/h | 5–8°C | 4–7°C |
| Data center | 35°C | 27°C | 22°C | 700 m³/h | 6–10°C | 4–7°C |
| Process cooling | 45°C | 32°C | 26°C | 600 m³/h | 8–15°C | 5–9°C |
| Power plant | 42°C | 30°C | 24°C | 5,000 m³/h | 10–14°C | 4–8°C |
| Refrigeration | 38°C | 29°C | 24°C | 350 m³/h | 7–10°C | 4–7°C |
Cooling Tower Design Guidance
Start With Reliable Design Weather
Cooling towers depend strongly on entering wet-bulb temperature. Use a defensible summer design value. Avoid average weather for critical selections. Check local records and project requirements. Higher wet bulbs reduce available cooling potential. They usually increase required tower size. A lower wet bulb improves apparent performance. However, seasonal control still needs careful planning.
Understand Range and Approach
Range describes the water temperature reduction. Approach measures closeness to wet-bulb temperature. Small approaches demand larger heat-transfer surfaces. They also demand stronger airflow and distribution. Large ranges reduce required water flow. Yet, process limits may restrict temperature differences. Always verify equipment return temperatures. Consider partial-load conditions and winter operation.
Use Correct Heat-Rejection Duty
Cooling towers reject more than compressor cooling output. Chiller heat rejection includes compressor energy. Process systems may include pump heat. Piping gains can also affect duty. Use measured data whenever available. Otherwise, document every assumption clearly. Include future growth only when justified. Excessive margins waste capital and energy.
Evaluate Water Consumption Carefully
Evaporation normally dominates water use. Blowdown depends heavily on concentration cycles. Drift depends on eliminator performance. Leakage and overflow should remain small. Higher cycles reduce blowdown demand. However, scaling and corrosion risks increase. Water chemistry limits must govern final cycles. Treatment specialists should review the program.
Check Fan and Pump Energy
Fan energy changes strongly with airflow. Variable-speed drives improve part-load efficiency. Pump power depends on flow and head. Avoid excessive distribution pressure. Verify nozzle requirements with suppliers. Measure realistic pipe friction losses. Include motor efficiency and operating hours. Energy costs can dominate lifecycle decisions.
Select Practical Cell Arrangements
Multiple cells improve staging and redundancy. Each cell needs acceptable minimum flow. Excessive flow can overload fill sections. Standby cells improve reliability. They also increase initial project cost. Consider maintenance access and isolation valves. Use N plus one when justified. Confirm basin and piping arrangements early.
Review Site and Layout Effects
Nearby walls can cause air recirculation. Discharge air may return to inlets. This raises effective entering wet bulb. Wind direction also changes performance. Provide adequate separation and discharge height. Consider plume impacts on nearby structures. Check noise limits at property boundaries. Access space supports future maintenance.
Confirm Final Selection Properly
This calculator provides preliminary engineering estimates. Manufacturer software should verify final selections. Certified performance data remains essential. Water distribution must match supplier limits. Structural loads require separate engineering review. Electrical systems need coordinated motor data. Controls must support staging and protection. Final design decisions require qualified engineering judgment.
Frequently Asked Questions
What is cooling tower sizing?
It matches tower capability with required heat rejection.
What is cooling range?
Range equals hot water minus cold water.
What is cooling approach?
Approach equals cold water minus entering wet bulb.
Why is wet-bulb temperature important?
It defines the evaporative cooling limit.
How is tower capacity calculated?
Capacity follows water mass flow, heat capacity, and range.
What is a cooling tower ton?
It represents a conventional tower heat-rejection basis.
How is evaporation loss estimated?
Use heat balance or an empirical range coefficient.
What is cooling tower blowdown?
It removes concentrated water from the circulating system.
What are cycles of concentration?
They compare circulating dissolved solids with makeup water.
How much makeup water is required?
Add evaporation, drift, blowdown, and other losses.
What safety factor should be used?
The proper margin depends on uncertainty and project risk.