Cooling Tower Nozzles: Small Components Determine High Energy Efficiency

Cooling towers are the "radiators" of industrial water circulation systems, while nozzles are their "pores". If the pores are clogged or unevenly distributed, the heat dissipation efficiency of the entire tower will be greatly reduced. This article, in combination with the latest research, takes you to reacquaint yourself with this unremarkable yet energy-efficient little component.

I.Cooling Tower Nozzles: Determines 70% of the packing utilization rate

Measurements conducted by Tianjin University of Science and Technology show that over 70% of the effective cooling of the cooling tower occurs in the packing section. Whether the packing can be "fed" with cold water depends crucially on whether the nozzles can tear each stream of water into uniform water droplets. If the uniformity coefficient of water spray rises from 0.2 to 0.7, the water temperature at the outlet of the tower will increase by 4 ℃, and the coal consumption of the unit will soar accordingly.

II.Cooling Tower Nozzles:There are three common schools

Gravity splashing type: It relies on the self-weight of water droplets to strike the splashing disc, forming an umbrella-shaped water curtain. It has the lowest energy consumption, but is greatly affected by wind and is suitable for medium and small-sized counter-flow towers.

Rotary jet type: Tangential water inlet rotates at high speed in the cavity. The centrifugal force "throws" the water flow into a hollow cone, providing excellent atomization effect and strong anti-clogging performance. It is often used in large towers of power plants.

Reflective Type III: By adding a circle of reflective plates at the jet nozzle, water droplets can collide a second time, taking into account both atomization and water drift prevention. It is the preferred choice for the renovation of central air conditioning cooling towers in recent years.

III. Cooling Tower Nozzles:Three-step Method for Selection

Material matching working conditions: Municipal tap water or circulating water is slightly neutral. ABS can be selected, with a lifespan of 10 to 15 years. If the chloride ion content in the water is greater than 100 mg/L, it is recommended to switch to chemically resistant PP or glass fiber reinforced nylon.

First, determine the flow rate, then select the diameter: For a single-tower 500 m³/h system, 80 DN25 rotary jet nozzles are commonly used, each rated at 6.3 m³/h. Under a working water head of 8 kPa, a theoretical coverage diameter of 1.2 m can be achieved.

The layout density is "dense on the outside and sparse on the inside" : At the periphery close to the wall, a regular triangular spacing of 0.8m is adopted to prevent short circuits in the dry area. The central air flow rate is high, and a regular quadrilateral 1.0m can be used to reduce investment while ensuring the air-to-water ratio.

IV.Cooling Tower Nozzles:Don't let "minor blockages" drag down the annual energy efficiency

Actual measurements show that a 2-mm scale ring at the nozzle outlet can reduce the flow coefficient by 18%, which is equivalent to increasing the pump head by 1.5 meters to "make up for it". Reverse flushing once a month and disassembling and inspecting 10% of the samples every quarter can keep the water drift rate below 0.001%, saving 20,000 kWh of electricity throughout the year.

V. Cooling Tower Nozzles:Upgrade Tips

If the packing height of the old tower is less than 1 meter, the original gravity nozzles can be replaced as a whole with low-pressure rotary jets. The spray height will be reduced by 0.3 meters, which is equivalent to "stealing" 30% of the heat exchange space. The water temperature leaving the tower will drop by another 0.8 ℃, and the COP of the chiller will increase by 3%. The investment can be recovered in less than one cooling season.

Don't let the cooling tower become a "showerhead" - only by ensuring that every drop of water precisely lands on the packing can the heat be thoroughly "washed" into the atmosphere. By choosing the right nozzles, positioning them properly and maintaining them frequently, you will have mastered the golden key to the energy efficiency of cooling towers.