Water consumption in absorption chillers is not negligible: Water-for-cooling consumption of chiller systems for commercial buildings in the United States

摘要

We compare peak electricity demand and water-for-cooling consumption of two electric chillers –air-cooled andwater-cooled– to that of a natural gas-fired heat-driven chiller – an absorption chiller – in the United States. Wedevelop a mass-and-energy-balance model in which each chiller supplies the cooling demands of 16 commercialbuilding types in 15 climate zones of the contiguous US. We quantify the water-for-cooling of each chiller withintwo categories: (1) ‘cooling and power’ (CP) – the sum of water consumed directly by each chiller and waterconsumed at the point of power generation; and (2) ‘total’ – the sum of CP water consumption and waterconsumption upstream from the power generation. The air-cooled, water-cooled and absorption chillers consumean average of 2.43, 3.73 ± 0.25, and 3.78 ± 0.35 m~3 of CP water per MWh of cooling, respectively. Theyconsume an average of 9.26, 8.32 ± 0.25, and 3.89 ± 0.34 m~3 of total water per MWh of cooling, respectively.That is, life cycle water consumption for natural gas-based absorption chilling is not negligible, though it is lowerthan for the electricity-based chillers under current grid conditions. Lower power grid life cycle water consumption,e.g., under decarbonization, could change this relationship.