The combined radiant floor and fan coil cooling (RFCAFC) system is widely used due to its high comfort and large energy saving potential. In this study, as an example, the combined RFCAFC system was studied in a high humidity environment in Jinan, Shandong Province, China. The novelty of the combined RFCAFC system lies in its ability to automatically adjust the water supply temperature of the radiant floor and fan coil in real time according to outdoor meteorological conditions, achieving thermal comfort while eliminating the likelihood of condensation on the radiant floor surface. Days with similar outdoor meteorological conditions were grouped, and the comfort level and hourly cooling performance coefficient (EER_h) of different operating strategies for different outdoor meteorological conditions were monitored along with other evaluation indicators. The RFCAFC had good energy efficiency and comfort in a high humidity room environment. This study showed that the indoor vertical air temperature difference ranged from 1.6 to 1.8 °C, which met the ASHRAE55-2017 standard. The radiant floor surface temperature uniformity coefficient (S) fluctuated between 0.7 and 1.0, and the time it took the radiant floor surface temperature to reach 63.2% of the total variability range (τ₆₃) for different operation strategies based on different outdoor meteorological conditions ranged between 4.4 and 4.7 h, which was within the normal range. The proportion of the total cooling capacity contributed by fan coil cooling under low temperature and high humidity (LH), high temperature and low humidity (HL), and medium temperature and medium humidity (MM) were 68.0%, 73.8%, and 71.7%, respectively. Based on this study, the following recommendations for the combined cooling system can be made: (1) When the outdoor humidity is high, the radiant floor system should be turned on early to provide cooling capacity. When the outdoor temperature is high, the fan coil system should be turned on early to reduce the indoor temperature. (2) To reduce energy consumption and achieve efficient operation of the system, the radiant floor system should be continuously operated to maximize its contribution to the cooling capacity, while the fan coil can be operated intermittently. Natural cooling can be integrated to provide additional cooling capacity to the room in the hours preceding occupation (i.e., 7:00–9:00). (3) The operation strategy of the combined cooling system must be able to respond in real time to changes in outdoor meteorological conditions to prevent discomfort in times of extreme heat or humidity.

The current situation of Coronavirus Disease 2019 (COVID-19) prevention and control coupled with the need to work in high-temperature harsh environments makes it necessary to ensure the health and efficiency of medical staff. An experimental outdoor work tent was set up and university students were used to study the thermal comfort of personnel wearing protective clothing in hot and humid environments. The experiment was carried out simultaneously through subjective and objective field tests and physiological tests of personnel. The wet bulb globe temperature (WBGT) index was investigated to divide the outdoor thermal environment into four working conditions: 21–23 °C, 23–25 °C, 25–27 °C and 27–29 °C. Under the different thermal environment intensities, the variations of physiological parameters of test personnel were monitored. The results showed that when WBGT was increased to 27–29 °C, 100% of the participants expected the external temperature to become cooler and the humidity to decrease after one hour. When the temperature was close to 30 °C and the relative humidity was close to 60%, it was necessary to take cooling measures to reduce the thermal stress of the participants. Moreover, relationships between subjective feelings and physiological parameters of the nucleic acid sampling personnel were obtained. Results also found that the forehead, chest and back were the highest skin temperature parts, so it is most effective to give priority to improving the thermal comfort of these three locations. As an early attempt to conduct the real outdoor experimental study on the thermal comfort of COVID-19 nucleic acid sampling staff, this study provided a theoretical basis for follow-up research to develop cooling strategies for protective clothing in hot and humid outdoor environments.

Office buildings are significant contributors to energy consumption and carbon emissions due to high occupancy density and prolonged operation. To balance decarbonization with indoor environmental quality, this study proposes a simulation-driven multi-strategy optimization framework for a three-story office building in Jinan. This study integrates EnergyPlus 23.2, jEPlus+EA 2.3.2, and the NSGA-II algorithm to co-optimize building performance. We evaluate the synergistic effects of roof photovoltaic coverage ratio, night ventilation turn-on temperature difference, and HVAC control strategies on carbon emissions and thermal comfort, while ensuring that CO₂ concentrations remain within health thresholds. The results indicate that the night ventilation temperature turn-on temperature difference is the most influential parameter. It yields standardized regression coefficients (SRCs) of 0.7456 for carbon emissions and 0.5325 for thermal discomfort. The Pareto-optimal solution achieves a carbon footprint of approximately 477 tCO₂, with only 8.8% indoor discomfort hours. This framework provides a robust, practical approach for the low-carbon and healthy operation of office buildings.