Grant: Alliance Grants

The elevated temperatures associated with global warming require new investment in large-scale cooling e.g. energy-intensive processes like power generation. Oftentimes, industry uses mechanical-draft cooling towers, which rely on evaporative cooling, to meet cooling demand. In turn, cooling towers generate steam plumes that may condense causing reduced visibility and, in especially cold conditions, ice accretion. Thus do cooling towers impose hazards to infrastructure when situated adjacent to, say, highways or industrial installations. The hazards can be mitigated by leveraging sensible as well as latent heat exchange, a strategy that is in any event necessary in arid regions. The combination of wet and dry cooling must be pursued with caution, however, because of the low efficiency of the latter. Our research project will extend a productive, 8-year university-industry collaboration devoted to studying the above challenges. We will focus on understanding the dynamics of "crossflow" forced-draft cooling towers, which cannot be modeled using the one-dimensional frameworks suitable for other, simpler designs. In this context, we will develop a theoretical/numerical model that describes the heat and mass transfer processes that occur inside and above such cooling towers. Thus will we characterize, for various climatic conditions, the change of operating conditions necessary to avoid a visible plume without limiting cooling efficiency. Such characterizations will reference not only details of the tower design but will, in a novel extension of our modeling efforts, also consider mixing processes interior to the cooling tower itself. This industry collaborative project will directly benefit Canada e.g. by providing an essential software design tool to a Canadian cooling tower company. Thereby will the energy- and cost-saving measures identified as part of this research find their expression in the Canadian marketplace and beyond.