Redesign of Cooling System in Dubai Mall “Grove”
Dubai mall is shopping destination for people across the globe. Using the CFD analysis it was ensured that the air conditioning system in Dubai mall is sufficient to cool the main atrium, called “grove” in peak heat load condition. The objective of the CFD simulation is to verify if the new air-conditioning system inside the Dubai mall is sufficient to provide a comfortable temperature of 25oC during peak summer condition of about 47 oC in Dubai. For peak load condition, weather data from ASHRAE reference manual in summer is used. The weather data was used to determine the peak temperature, humidity and peak direct solar radiation coming from the sun.
Modeling and Analysis
A 3D model was created for the Grove section of the Dubai Mall using Pre processing tools. Then the model was discretized using appropriate meshing scheme. It was assumed that the maximum human capacity inside the Grove is approximately 300. Also 75 W of latent and sensible heat gain per human being was taken from ASHRAE Handbook chapter 8. A thermal and moisture source is applied inside the Mall during the simulation. A fixed lighting load of 40 W/m2 is applied on the inner wall of the building. 20 Number of Rack Air Conditioning (RAC) units were placed in the Grove and outdoor temperature of 46ºC DBT and 30ºC WBT was considered. The inlet air temperature from the RAC unit was 12 ºC and the solar emissivity of the dome was 0.4. The analysis was done in three scenarios considering fans running at different fan speed and different relative humidity level inside the grove with various scenarios of solar radiation. The theoretical maximum weather condition was selected as maximum temperature – 46ºC, average relative humidity during the summer months –30% and maximum normal solar radiation flux 8663 Wh/m2.
After doing CFD Analysis of Dubai Mall we get the temperature contour and the relative humidity at different heights for vertical and horizontal plane. The below table describes the three cases considered and the temperature and the relative humidity in the grove at 3.2m height from the surface.
From the table we can understand that in all the three conditions the air-conditioning system is sufficient enough to maintain human comfort for human occupied space during worst possible weather conditions.