SUMMARY
The calculation of water pressure drop in a cooling tower piping system utilizes the Hazen-Williams equation, specifically designed for closed circuit chilled water systems. The equation is defined as h100ft = 0.2083 x (100 / c)^1.852 x q^1.852 / dh^4.8655, where h100ft represents friction head loss, c is the Hazen-Williams roughness constant, q is the volume flow in gallons per minute, and dh is the inside hydraulic diameter in inches. For open circuit systems, such as cooling towers, the equation remains applicable, but considerations for atmospheric pressure at the pump intake and the discharge conditions at the sprayers must be integrated. Additionally, temperature variations of the water throughout the piping circuit must be accounted for in the calculations.
PREREQUISITES
- Understanding of the Hazen-Williams equation for fluid dynamics
- Knowledge of hydraulic diameter and its significance in pipe flow
- Familiarity with concepts of atmospheric pressure and NPSH (Net Positive Suction Head)
- Basic principles of thermodynamics related to temperature changes in fluids
NEXT STEPS
- Research modifications to the Hazen-Williams equation for open circuit systems
- Learn about pump NPSH calculations to prevent cavitation in cooling tower applications
- Study the effects of temperature changes on water density and pressure drop
- Explore advanced fluid dynamics simulations using software like ANSYS Fluent
USEFUL FOR
Engineers, HVAC professionals, and anyone involved in the design and optimization of cooling tower systems will benefit from this discussion.