Thermal Comfort And IAQ Assessment For An Air-conditioning Train Compartment

To exactly realize and comprehensive evaluate the thermal comfort and indoor air quality (IAQ) in a train compartment is very important for the improvement of the living condition of the passengers and AHVAC technology.Taking YZ-25T train compartment as a model, using CFD software PHOENICS, indoor airflow of nature convection are simulated, the field of air temperature, velocity and relative humidity in winter days are offered and analyzed.After analyzing the fuzziness of thermal comfort and the main causcs of thermal comfort dissatisfaction in cold winter days, a two-layer evaluation index system is constructed, a two-layer fuzzy comprehensive assesment model for winter thermal comfort is built correspondingly. Based on gradation of thermal sensation index and drought sensation Index, the membership of each index to its factor is constructed. Through Analytical Hierarchy Process method (AHP) the weight of each factor (air temperature, air velocity, relative humidity) influencing thermal sensation is determined. This model clearly introduces the impact of drought sensation by relative humidity into thermal comfort fuzzy comprehensive assessment.Bring the simulative results of the train compartment into the fuzzy comprehensive assessment model for winter thermal comfort, the thermal assesment index is given by mathematical software MATLAB, so the thermal comfort state of each passenger is able to be investigated.Some pollutants concentration data in train compartment is collected and IAQ is evaluated by fuzzy comprehensive evaluation and grey incidence analysis. The assesment results of both methods are almost unanimous. A new way to deal with the calculation results of grey incidence analysis is proposed, and achieved fairly good results.