HVAC

Case study: Convention center addition

Thermal comfort was a key component of the Washington State Convention Center addition.
By Peter Alspach, PE, LEED AP May 29, 2019
Figure 7: On the “hill climb” of the Washington State Convention Center addition, seating areas adjacent to the glazing create comfort challenges. Courtesy: LMN Architects

The new Washington State Convention Center addition is a 1.4millionsquarefoot stand-alone facility that is providing significant expansion of exhibit and meeting space for the convention center. It is a unique approach to convention center design, providing an urban, vertically stacked programming that allows it to fit within tight urban site constraints compared to the typical horizonal sprawl of most convention centers.  

A key part of the program is the vertical circulation that extends from 40 feet below grade to more than 200 feet above grade. LMN Architects designed a signature stair and escalator “hill climb on the southern edge of the building, bringing the circulation to the exterior and allowing the activity within the convention center to visually activate the building.  

Figure 7: On the “hill climb” of the Washington State Convention Center addition, seating areas adjacent to the glazing create comfort challenges. Courtesy: LMN Architects

A key design aspect of the hill climb are its landings and seating areas located against the glass within the 240foothigh atrium. For these areas to be successful they need to be comfortable, and this was a key design requirement for the owner; their current facility has faced thermal comfort challenges in a much smaller volume with less exterior exposure.  

In such a challenging space  tall glazed walls, southern exposure and the potential for stratification  the design team used a combination of radiant floor heating and cooling along with computational fluid dynamics design of the air distribution system. The CFD design allowed tuning of air distribution to minimize stratification and add extra air supply to the areas where the radiant floor needed additional heating or cooling capacity 

Figure 8: For the Washington State Convention Center “hill climb” comfort analysis, computational fluid dynamics results documented the final design’s comfort conditions. Courtesy: Arup

CFD also has the advantage of being able to evaluate all the aspects required to show compliance with ASHRAE Standard 55: Thermal Environmental Conditions for Human Occupancy: average air speed, air temperature, mean radiant temperature and incident direct solar. While not all spaces need CFD to help design for comfort, in extreme cases such as this it is an invaluable tool.  

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Peter Alspach, PE, LEED AP
Author Bio: Peter Alspach is the director of design performance at NBBJ and was previously a principal at Arup. His expertise includes high-performance building engineering design and analytics.