Description

Most comfort indices for indoor environment are based on static ensemble clothing insulation and assumed sedentary activity level at low air velocities. However, to consume less energy, research has recently focused on increasing velocity to bring thermal comfort at elevated air temperatures by enhancing ventilation through clothing. This work aims to implement an integrated heat transport model of clothed human body subject to external wind. Each clothed segment of the human body is modeled as a vertical annulus of a heated cylinder surrounded by a permeable cylinder, subject to cross uniform wind with open or close end to the environment, depending on the aperture configuration, in the presence of natural convection. The flow and heat transport characteristics are obtained by solving the steady state mass and energy balance equations of body segments ’microclimate air annulus numerically. Experiments were performed in a low speed wind tunnel in which an isothermally heated vertical clothed cylinder with open bottom aperture was placed in uniform cross wind. Good agreement was found between the model predictions and experimental measurements of temperature at different angular and vertical location in the microclimate air layer. It is found that clothed segments opened from bottom increases ventilation rate by 40 % when compared to clothed segments opened from top. Furthermore, an increase of wind speed by 1 m/s (3.28 feet/s) leads to an increase of about 36 % of ventilation rate. Permeability also plays another role in enhancing ventilation and total heat loss from the clothed segment especially when natural convection is important. At wind velocity less than 2 m/s (6.56 feet/s) , the increase in ventilation and heat loss by moving from semi permeable clothing to permeable clothing were around 20% and 19 % respectively.

Citation: International Conference on Efficient Building Design, Materials and HVAC Equipment Technologies; October 2-3, 2014; Beirut, Lebanon

Product Details

Published:

2014

Number of Pages:

8

File Size:

1 file , 1.7 MB

Product Code(s):

D-ICEB14-06