Abstract
Sales of air conditioning are growing rapidly in buildings, more than tripling between 1990 and 2016. This energy use for air conditioning comes from a combination of rising temperatures, rising population and economic growth. Energy demand for climate control will triple by 2050, consuming more energy than that currently consumed altogether by the United States, the European Union and Japan. This increase in energy will directly impact water consumption, either to directly cool a condenser of an equipment or to serve indirectly as a basis for energy sources such as hydroelectric power that feed these heating, ventilation and air conditioning (HVAC) systems. Knowing the unique and growing importance of water, a new index, Total Water Impact (TWI) is presented, which allows a holistic comparison of the impact of water use on water, air and evaporative condensation climate systems. 200 and 500 TON (tons of refrigeration) air-cooled and water-cooled systems are theoretically compared to evaluate the general water consumption level. The TWI index is higher in the smallest water condensing system. That is, holistically, water consumption is higher in the water condensing system than in the air condensing system. Thus, this index provides a new insight about energy consumption and ultimately, about sustainability.
Highlights
According to the Worldwide Fund for Nature (WWF) [1], there are more than 326 quintillion liters of water on earth
In the case of the 500 TON power system, where the 2013 ASHRAE 90.1 values were used as the NPLV source, the Total Water Impact (TWI) index value was lower in the air-cooled chiller
The Total Water Impact (TWI) index provides a holistic view of water consumption over a period of time
Summary
According to the Worldwide Fund for Nature (WWF) [1], there are more than 326 quintillion liters of water on earth. According to the Brazilian Ministry of Environment [2], freshwater is not evenly distributed across the globe. South America, there is 26% of the total available freshwater on the planet and only 6% of the world population. Asia has 36% of total water and is home to 60% of the world’s population (see Figure 1) [3]. UN data [4] indicate that a European, who has 8% of the world’s freshwater on its territory, consumes an average of 150 liters of water per day. According to UNESCO estimates to 2025, based on the current rate of population growth and the Energies 2020, 13, 1590; doi:10.3390/en13071590 www.mdpi.com/journal/energies. Figure and water distribution [3].[3]. 73% of of the the country’s country's available freshwater is is in in the the Amazon.
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