Cooling tower performance analysis and visible air plume abatement in buildings situated in temperate climate zone

Doctoral thesis English OPEN
Chan, Man-Him
  • Subject: NA

Visible plume was considered as a nuisance to the public due to health and visual issue especially in urban cities, and so heat coils were installed within cooling tower to carry out visible plume abatement. However, as it would be difficult in building to find heat source and high electricity consumption with heat coil, an alternative approach is required. \ud Prior of developing a visible plume abatement approach, it was essential to identify the formation of visible plume. With this respect, a sophisticated mathematical model, the Poppe Approach was studied and developed a web-based calculator based on the theory. A real size mechanical cooling tower in China was constructed to carry out a validation test and showed to be very accurate and more accurate than the industrial approach, the Merkel Approach.\ud Based on this validated Poppe Approach, an artificial environmental chamber was designed and constructed in China, and tests were conducted to identify the visible plume formation. CFD simulations were conducted to compare with the experimental results to validate the CFD simulation itself.\ud Meanwhile, an alternative visible plume abatement approach was developed, the water shedding approach. The water shedding approach was designed to reduce the hour of visible plume occurrence and also to reduce the severity of visible plume. A building load of a commercial building was used to carry out visible plume abatement evaluation with the water shedding approach. With a Hong Kong climatic data, hours of visible plume would reduce by 38.2% and severity of visible plume was reduced by 40 – 60%. \ud With the validated CFD simulation and the water shedding approach, CFD simulation was conducted in an urban city environment and with cooling tower operating with and without the use of water shedding approach. It was found that CFD simulation results showed that there was a maximum reduction in temperature of 0.33 oC and maximum moisture content of 0.0003 kgDA/kgM. In order to bridge the gap between academic and industry, a web-based platform was created that stored information related to cooling tower, as well as the fast calculators (the Poppe Approach calculator and the visible plume abatement calculator) developed during this research topic. This web-based platform would provide engineer a user friendly tool to carry out evaluation in cooling tower plant design and visible plume abatement evaluation.
  • References (1)

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