Evaluation of climatic zones and field study on thermal comfort for underground engineering in China during summer

The researches on thermal comfort for underground engineering are lacking in China. In this paper, ground temperature (T-g), ventilating sensible heat ratio (VSHR) of fresh air in 249 cities of different areas were calculated, and four climatic zones including Cold, Dry, Humid, Hot&Humid were established. Through field surveys from June 1 to September 30 during the period 2007-2015, larger amounts of measured data and 5862 effective questionnaires were obtained in non-air conditioned defense basement in the four climatic zones. Results showed that the mean thermal sensation (MTS) values did not agree with the values of PMV model. At the same operative temperature of 27 degrees C, the values of MTS were 0.53, 0.47, 0.32 and 0.0 in Cold, Dry, Humid and Hot&Humid climatic zone, respectively. When T-op was more than 26 degrees C, more than 84% of the occupants expect 'no change' in the four climatic zones, especially 91% in Hot&Humid zone. When relative humidity (RH) was more than 80%, most of the occupants' thermal acceptability (TA) was less than - 0.3. In addition, by using multiple regression techniques, the neutral temperature models were derived using the parameters of average outdoor temperature, T-g, RH and clothing value for different climatic zones.