Field Measurement and Thermal Comfort Evaluation of Window-Type Direct Evaporative Cooling (DEC) across 50 Dormitory Rooms in a University Residential Building in Beijing Temperate Climate Zone

This study employs a multi-method, high-precision research approach to evaluate the thermal comfort performance of a window-based direct evaporative cooling (DEC) air conditioning system installed in a university dormitory building (Building 6, 50 rooms) in Beijing. To compensate for the insufficiency of single-day test data, the study was conducted continuously for 30 days from June 1st to 30th, 2026 (00:00–23:59 daily). The research integrates field physical measurement data, standardized subjective questionnaire surveys (200 questionnaires in total), and advanced computational thermophysiological modeling results based on the frameworks of ISO 7730–2021 and ASHRAE Standard 55–2023. Environmental parameters, including dry-bulb temperature (Ta), relative humidity (RH), air velocity (Va), and mean radiant temperature (Tr), were monitored at eight spatially distributed points with a 10 Hz sampling frequency and a one-hour median resolution. Simultaneously, through confirmatory pre- and post-questionnaires compliant with ISO 10551 and the Appendix B requirements of ANSI/ASHRAE Standard 55, data on clothing ensembles, activity levels, and subjective thermal sensation votes (TSV) were collected. The acquired data were input into a customized simulation platform developed in the Fortran language, which employs the Fanger two-node thermoregulation model to accurately calculate and predict the predicted mean vote (PMV), predicted percentage of dissatisfied (PPD), new effective temperature (ET*), and standard effective temperature (SET*). The results indicate that the DEC unit achieved a stable outlet temperature reduction of t =3.87°C (inlet temperature 31.72°C, outlet temperature 27.85°C), with a stable average wet-bulb air temperature was 18.66°C while maintaining a relative humidity of 42.07%—a result particularly crucial for Beijing's high-humidity summer environment.