Effect of Air Supply Temperature on the Performance of Displacement Ventilation (Part I) - Thermal Comfort

The effect of the air supply temperature on the performance of a displacement ventilation (DV) system has been investigated. The study looks into the case of a typical office building in Hong Kong, under local thermal environment and airflow conditions. These are characterised by the high cooling load density, which commonly occurs in Hong Kong. The lower supply temperatures were found to result in higher draft effects, yet increasing temperatures leads to an increase in the predicted percentage of dissatisfied people (PPD). The DV system was found to provide acceptable thermal comfort at certain air supply temperatures. The levels of PPD could be marginal should the parameters of the system not be optimised.

[1]  Povl Ole Fanger,et al.  Turbulence and draft , 1989 .

[2]  Hui Zhang,et al.  Testing and optimizing the performance of a floor-based task conditioning system , 1995 .

[3]  Qingyan Chen,et al.  System Performance Evaluation and Design Guidelines for Displacement Ventilation , 1999 .

[4]  Povl Ole Fanger,et al.  Turbulence and draft. The turbulence of airflow has a significant impact on the sensation of draft , 1989 .

[5]  B. Launder,et al.  The numerical computation of turbulent flows , 1990 .

[6]  Qingyan Chen,et al.  A new turbulence model for near-wall natural convection , 1998 .

[7]  Qingyan Chen,et al.  Influence of air supply parameters on indoor air diffusion , 1991 .

[8]  Qingyan Chen,et al.  Prediction of room air motion by Reynolds-stress models , 1996 .

[9]  Ayech Benjeddou,et al.  A Piezoelectric Mixed Variational Theorem for Smart Multilayered Composites , 2005 .

[10]  Standard Ashrae.  Thermal Environmental Conditions for Human Occupancy , 1992 .

[11]  Qingyan Chen,et al.  Measurements and computations of room airflow with displacement ventilation , 1999 .

[12]  Alan H. Huber.  Performance of a Gaussian model for centerline concentrations in the wake of buildings , 1988 .

[13]  Chen Qingyan,et al.  Measurements and computations of ventilation efficiency and temperature efficiency in a ventilated room , 1988 .

[14]  Qingyan Chen.  COMPARISON OF DIFFERENT k-ε MODELS FOR INDOOR AIR FLOW COMPUTATIONS , 1995 .

[15]  L. R. Glicksman,et al.  Models for prediction of temperature difference and ventilation effectiveness with displacement ventilation , 1999 .

[16]  Haiying Wang,et al.  Experimental Study of Factors That Affect Thermal Comfort in an Upward-Displacement Air-Conditioned Room , 2002 .

[17]  Qiuwang Wang,et al.  Validation of CFD Model for Research into Displacement Ventilation , 2005 .

[18]  Qingyan Chen,et al.  A critical review of displacement ventilation , 1998 .

[19]  S. Tanabe,et al.  Development and application of an underfloor air-conditioning system with improved outlets for a 'smart' building in Tokyo , 1995 .

[20]  S. Orszag,et al.  Development of turbulence models for shear flows by a double expansion technique , 1992 .

[21]  J. E. Janssen,et al.  Ventilation for acceptable indoor air quality , 1989 .

[22]  Tin-Tai Chow,et al.  A Partial Differential Model for the Pyrolysis of Materials with Movable Residual Layer , 2005 .