Passive Cooling Techniques for a High Rise Hotel

By:Aaron Neal

Designing a high rise hotel can be challenging in its own right, but what are some ways to add some sustainable features to the design?  This is the focus of my current studio project, and I have looked into a couple of ways to passively cool down my building.  To start off with, I wanted to create my hotel around a large atrium where all of the guest rooms could look down into the main lobby space.  This atrium has many design issues to take into consideration in regards to fire safety.  In a fire smoke will rise up the atrium like a chimney so I will need to design a system that ventilates and draws the smoke out at the top.  I can use this system passively by having the vent open to let hot air rise up and out of the building.  This effect works well when there are operable down in the main lobby to create a draft that draws air from the bottom up through the atrium.   In my design I placed a fountain at the base of the atrium to allow for humidity to be drawn up along with the draft.  The water from the fountain also helps to cool the air as it rises. 

The other passive technique I am implementing into my design is a double skin façade.  I originally looked into having shading devices that doubled as balconies, but later decided to scrap the idea.  Balconies thirty stories up might be a bit dangerous for a public hotel.  Instead I wanted a smooth glass façade going up my high rise.  This is when I started to look into double skin facades and an option.  The system works by having normal windows on the interior layer, while having a glass screen about a foot or so offset the main exterior of the building.  This provides an air gap that takes in the majority of the thermal heat.  In the summer times when thermal gain is a concern, the air gap can have vents along the bottom and top open up to create a draft similar to the atrium.  This allows for all the thermal energy gained from the sun to be absorbed and then taken directly out of the top of the building without ever entering the building itself.  In the winter times, when thermal gain is good, the vents can be sealed off to trap the hot air within the air gap.  This acts as insulation for the entire building to keep the warm air trapped inside the building lowering heating costs.  Over all this façade system works quite well passively, and is easy to construct.  For an actual project, cost projections would be necessary to see if this system could be used in the project and to find out what the return value would be for a developer to invest into a system like this.