Sustainability in Energy and Water: Air-Cooled versus Water-Cooled Heat Rejection

While water-cooled systems often reduce building energy use, there has been a dramatic improvement in air-cooled chiller performance. Fresh water scarcity results in increased water treatment plant operational cost and distribution infrastructure maintenance cost, all of which lead to higher customer charges. Simultaneously, major growth of renewable energy generation in the grid energy mix affects both process water used and greenhouse gases emitted. The market's demand for sustainability through both energy and water efficiency must be weighed carefully as competing interests continue to evolve rapidly over the next several years. This parametric study evaluates the impacts of water-cooled chiller plants versus air-cooled chiller plants and identifies trends in energy and fresh water consumption.