A zonal model to predict the vertical temperature distribution of displacement ventilation system during human movement

The existence of stable and continuous temperature stratification in displacement ventilation systems could bring the advantages of energy savings and high ventilation efficiency. The disturbance effect of human body move-ment can weaken such kind of temperature stratification. Comprehending the variation of the temperature stratification during human body movement helps to formulate countermeasures in the design phase. Until now, empirical studies of the zonal model predicting the vertical temperature distribution with body movement in displacement ventilation are very scarce. This paper proposed a novel zonal model to predict indoor vertical temperature distribution with body movement disturbance based on the theory of piecewise linear distribution of temperatures. The vertical entrained air volume (me) caused by the movement is one of the important variables in the model. In this study, a series of simulations and experiments in the literature were applied to get the value of me, which distinguishes the difference between the traditional static models and present dynamic model. We found that the value of me is closely related to the dimensionless number Ri. me between two adjacent zones is almost 0 when Ri < 0.256. The relationship between Ri and me can be fitted by the equation (me =-0.197 x ln (Ri) -0.269, R-2 = 0.879) when Ri > 0.256. The predicted temperature stratification by present zonal model exhibits a great fit with experimental data. Our findings contribute to the prediction of the indoor vertical temperature distribution in the quasi-steady state with the disturbance from body movement, which reflects most of the real situations in DV.