{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,13]],"date-time":"2026-01-13T09:51:40Z","timestamp":1768297900610,"version":"3.49.0"},"reference-count":19,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2020,4,1]],"date-time":"2020-04-01T00:00:00Z","timestamp":1585699200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Energies"],"abstract":"<jats:p>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.<\/jats:p>","DOI":"10.3390\/en13071590","type":"journal-article","created":{"date-parts":[[2020,4,2]],"date-time":"2020-04-02T11:57:14Z","timestamp":1585828634000},"page":"1590","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["New HVAC Sustainability Index\u2014TWI (Total Water Impact)"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5306-6968","authenticated-orcid":false,"given":"Alexandre F.","family":"Santos","sequence":"first","affiliation":[{"name":"Department of Electromechanical Engineering, University of Beira Interior, 6201-001 Covilh\u00e3, Portugal"},{"name":"FAPRO\u2014Faculdade Profissional, 80230-040 Curitiba, Brazil"},{"name":"C-MAST\u2014Centre for Mechanical and Aerospace Science and Technologies, 6201-001 Covilh\u00e3, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1691-1709","authenticated-orcid":false,"given":"Pedro D.","family":"Gaspar","sequence":"additional","affiliation":[{"name":"Department of Electromechanical Engineering, University of Beira Interior, 6201-001 Covilh\u00e3, Portugal"},{"name":"C-MAST\u2014Centre for Mechanical and Aerospace Science and Technologies, 6201-001 Covilh\u00e3, Portugal"}]},{"given":"Heraldo J. L.","family":"de Souza","sequence":"additional","affiliation":[{"name":"FAPRO\u2014Faculdade Profissional, 80230-040 Curitiba, Brazil"}]}],"member":"1968","published-online":{"date-parts":[[2020,4,1]]},"reference":[{"key":"ref_1","unstructured":"WWF (2020, March 30). Programa Hidrol\u00f3gico Mundial. (In Portuguese)."},{"key":"ref_2","unstructured":"MMA (2020, March 30). \u00c1gua. Minist\u00e9rio de Meio Ambiente (MMA), (In Portuguese)."},{"key":"ref_3","unstructured":"WINS (2020, March 30). Water Information Network System (WINS) by the International Hydrological Programme ofUnited Nations Educational, Scientific and Cultural Organization (UNESCO). Available online: http:\/\/ihp-wins.unesco.org\/."},{"key":"ref_4","unstructured":"UN (2020, March 30). World Water Development Report 2019. Available online: https:\/\/www.unwater.org\/publications\/world-water-development-report-2019\/."},{"key":"ref_5","unstructured":"IBGE (2017). Anu\u00e1rio Estat\u00edstico, Instituto Brasileiros de Geografia e Estat\u00edstica\u2013IBGE. (In Portuguese)."},{"key":"ref_6","unstructured":"ANA (2013). Conjuntura dos Recursos H\u00eddricos no Brasil, Ag\u00eancia Nacional de \u00c1guas\u2014ANA. (In Portuguese)."},{"key":"ref_7","unstructured":"IEA (2020, March 30). Data and Statistics. Available online: https:\/\/www.iea.org\/statistics\/?country=WORLD&year=2016&category=Energy%20supply&indicator=TPESbySource&mode=chart&dataTable=BALANCES."},{"key":"ref_8","unstructured":"ABRAVA (2018). Semin\u00e1rio Brasileiro de Etiquetagem em Efici\u00eancia Energ\u00e9tica para sistemas AVAC, ABRAVA. (In Portuguese)."},{"key":"ref_9","unstructured":"NREL (2020, March 30). National Renewable Energy Laboratory, Available online: https:\/\/www.nrel.gov\/."},{"key":"ref_10","unstructured":"APREN (2018). Boletim Energias Renov\u00e1veis. Portugal, APREN. (In Portuguese)."},{"key":"ref_11","unstructured":"EPE (2019, September 13). 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LEED_v4.1_BDC_Rating_System_1.2020, U.S. Green Building Council."},{"key":"ref_16","unstructured":"AHRI_Standard_550-590 (2015). Performance Rating of Water-Chilling and Heat Pump Water-Heating Packages Using the Vapor Compression Cycle, Air-Conditioning, Heating, and Refrigeration Institute (AHRI)."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Al-Ghamdi, S.G., and Bilec, M.M. (2015). Life Cycle Thinking and the LEED Rating System: Global Perspective on Building Energy Use and Environmental Impacts, Civil and Environmental Engineering, University of Pittsburgh.","DOI":"10.1021\/es505938u"},{"key":"ref_18","unstructured":"ASHRAE (2016). ASHRAE Energy Water Nexus\u2013Denver, American Society of Heating, Refrigeration & Air Conditioning Engineers (ASHRAE)."},{"key":"ref_19","unstructured":"(2016). ASHRAE\/ANSI\/IES Standard 90.1-2016-energy Standard for Buildings except Low-Rise Residential Buildings, American Society of Heating, Refrigeration & Air Conditioning Engineers (ASHRAE)."}],"container-title":["Energies"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1996-1073\/13\/7\/1590\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:14:05Z","timestamp":1760174045000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1996-1073\/13\/7\/1590"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,4,1]]},"references-count":19,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2020,4]]}},"alternative-id":["en13071590"],"URL":"https:\/\/doi.org\/10.3390\/en13071590","relation":{},"ISSN":["1996-1073"],"issn-type":[{"value":"1996-1073","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,4,1]]}}}