An Energy Efficient Air Conditioning System using Displacement Ventilation and Chilled Ceiling for Modern Office Buildings

Thermal comfort and indoor air quality (IAQ) play a vital role in creating a pleasant and healthier indoor environment for occupants. The supply air conditions and the concentration of CO2 contaminant present in the supply air can decide the comfort level and purity of air in indoor environments. In this study, an effort was made to investigate the combined effect of a chilled ceiling and displacement ventilation (CC-DV) air conditioning (A/C) system that would possibly achieve good thermal comfort and IAQ in a proposed office building subjected to hot and humid climatic conditions. Simulation model analysis was performed under the MATLAB-Simulink environment to examine the thermal performance of the CC-DV system for different cooling capacities shared by CC and DV. Simulation results for classifying the required supply air conditions and mean contaminant removal efficiency are presented. Experimental results and existing convective correlations for floor level and head level temperatures in the occupied zone were used to validate and compare the simulation results respectively. The deviation observed between the experimental and simulation results for establishing the supply air temperature requirement was approximately ±10%. Similarly, the deviation between the simulation and the correlation results for head level temperature was ±4%. Based on the simulation model and experimental investigation performed on the CC-DV A/C system, the air supplied at 19 °C results in better thermal comfort and IAQ in indoor environments without compromising the energy conservative potential. In total, the overall energy conserved by the CC-DV system was 13.3% higher than a conventional constant air volume (CAV) A/C system operated under the same outdoor and indoor design conditions.