[New Paper] A systematic review on the role of humidity as an indoor thermal comfort parameter in humid climates

The accepted humidity limits indoors remain to be topical and widely discussed. There is a scarcity of scientific literature explaining the role of humidity as a thermal comfort parameter for spatial assessment. These studies focus on operative temperature as a primary parameter that influences thermal comfort, which also considers relative humidity and operative temperature.  In this context, the current paper attempts to answer the following research questions:

✅ How do existing standards, guidelines, and codes couple humidity to thermal comfort assessment?
✅  How do these standards, guidelines, and codes recommend humidity requirements?
✅ How do existing indoor physiological and psychological thermal comfort models for personalized assessment account for humidity?
✅ How do existing indoor thermal comfort indices incorporate humidity - a point-in-time or time-integrated approach?

This paper is part of the IEA Annex 80 ongoing activities to define resilient cooling in buildings. Many standards, like EN 16798, ISO 7730, BIS NBC, etc., prescribes an upper and lower threshold value for relative humidity, whereas standards like ASHRAE 55 do not provide any thresholds for relative humidity. Humidity coupling to thermal comfort models is more evident in PMV/PPD models, whereas the humidity signal is absent in adaptive model equations.

This paper analyzed how humidity was incorporated into spatial and personalized thermal comfort assessments and models. In addition, the paper studied different indoor thermal comfort indices in terms of index type and time temporality. The study found that most standards and guidelines recommended a fixed upper and lower threshold for humidity for spatial assessment. For personalized assessments, the humidity was indirectly coupled through evaporative heat losses in most physiological and psychological models. In addition, transient processes like metabolic activities that changed in warm temperatures and humidities also influenced human comfort perception. The existing indoor thermal comfort indices used a point-in-time approach regarding time temporality.Finally, the paper provides a set of suggestions and aspirations for practice and research based on the study findings.

✅ It has been almost two years since we started working on this article. I'm very thankful to the main author Deepak Amaripadath and the co-authors, Ramin Rahif, Mirjana Velickovic, and Shady Attia, for their valuable contributions and constructive comments!

🔴 Citation: Amaripadath, D., Rahif, R., Velickovic, M., & Attia, S. (2023). A systematic review on the role of humidity as an indoor thermal comfort parameter in humid climates. Journal of Building Engineering, 106039.

📣 Read and share the 📄 article. The paper is available in Open Access format: https://lnkd.in/eimcsaEM

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