## 5 Conclusions  
Sustainability and quality of life are topics of great importance today, but the important scientific question is how to measure them.  
One of the most participated sports is swimming, which, in countries and locations with cold and temperate climates, is only viable with indoor pools. One of the major problems of indoor pools is condensation on windows and walls. The technological solutions to reduce or eliminate condensation are dehumidifiers with refrigeration systems or desiccant wheels. A pool area of 45 m\({}^{2}\) was used as a base, and ASHRAE methodologies were used to determine the required dehumidification.  
Figure 9: Systems in Brazil and USA vs. Emissions CO\({}_{2}\) kg 10 years.  
In places with a less polluting energy matrix, the option of a desiccant wheel will generate a lower level of emissions (for example, Brazil) even when using more energy. Having a source such as green hydrogen [39] could even enable resistive systems with a desiccant wheel for dehumidification due to the absence of refrigerant fluid.  
Emissions from the energy matrix have a great influence on the TEWI value, but an important factor is the impact of the refrigerant gas inserted in the equipment. Environmental policies, such as green carbon, can help reduce these emissions, but also the use of low-GWP refrigerants should be a parallel measure to reduce emissions in HVAC-R (heating, ventilation, air conditioning, and refrigeration) applications.  
Future work considers the simulation of a desiccant system using solar energy in the reactivation, so the energy would be considerably reduced during the day. A desiccant solar system consists of a combination of solar energy for the reactivation system and a desiccant wheel and an evaporative system, which can be a solution in places with high solar irradiation [40], but the difficulty is that in these places the pools generally do not need to be covered [37]. Another alternative is to use natural refrigerant fluids (propane, carbon dioxide or ammonia) in refrigeration dehumidification systems that have extremely low GWPs, but in contrast, they either work at high pressure (CO\({}_{2}\)), or are combustible (propane) or toxic (ammonia) [38]. This methodology for measuring energy and CO\({}_{2}\) emissions through TEWI can be a way for institutions, such as AHRI and Eurovent, to create a standard to measure efficiency in desiccant wheel equipment, as there are Eurovent standards for regenerative air-air heat exchangers [41]. There are also standards available from AHRI [25], but they lack a procedure for desiccant wheels. In addition, this research work emphasizes the association of energy efficiency with CO\({}_{2}\) emissions that should guide future energy efficiency decisions [8].  
Conceptualization, A.F.S. and P.D.G.; validation, A.F.S. and H.J.L.d.S.; methodology, A.F.S.; investigation, A.F.S. and H.J.L.d.S.; formal analysis, A.F.S. and P.D.G.; resources, A.F.S. and H.J.L.d.S.; data curation, A.F.S. and P.D.G.; writing--original draft preparation, A.F.S., H.J.L.d.S.; writing--review and editing, P.D.G., V.N.G.J.S., J.M.L.P.C.; visualization, H.J.L.d.S.; supervision: P.D.G.; project administration, A.F.S.; funding acquisition, P.D.G., V.N.G.J.S. and J.M.L.P.C. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Data Availability Statement: Data can be found in the references cited in the manuscript.  
P.D.G. acknowledges the Fundacao para a Ciencia e a Tecnologia (FCT--MTES) for its financial support via project UIDB/00151/2020 (C-MAST). V.N.G.J.S. and J.M.L.P.C. acknowledge that this work is funded by FCT/MCTES through national funds and, when applicable, co-funded EU funds under the project UIDB/50008/2020.  
The authors declare no conflict of interest.