The art of designing sports, entertainment, and specialty structures: HVAC

Entertainment venues are big businesses—and big on complexity, with a host of complex systems and requirements for engineers to tackle. Heating, ventilation, and air conditioning are a big-ticket engineering challenge.

By Consulting-Specifying Engineer August 25, 2017

Respondents

  • Steve Brown, Certified Automation Professional Vice President and Operations Director, Energy & Automation Teams Environmental Systems Design Chicago
  • Daniel P. Christman, PE, LEED AP Vice President/Entertainment Market Sector Leader exp Orlando, Fla.
  • Keith Esarey, PE, LEED AP Principal McClure Engineering St. Louis
  • Tony Hans, PE, RCDD, LEED AP Vice President CMTA Louisville, Ky.
  • Mike Hart, PE, LEED AP Principal, CEO ME Engineers Golden, Colo.
  • Doug Lancashire, PE, LEED AP, CEM, CGBE Vice President, Director of Energy/Facility Systems Osborn Engineering Cleveland
  • Chris Skoug, PE, CEM Principal Engineer Southland Engineering Dulles, Va.  

CSE: What unique HVAC requirements do specialty facilities have that you wouldn’t encounter in other buildings?

Esarey: Large swings in occupancy can wreak havoc with an HVAC system. We had to develop strategies for controlling the system at specialty structures during normal hours of operation when the spaces are partially or lightly occupied. Humidity is a major concern for these kinds of structures as well as noise, which is a common issue in performance centers.

Skoug: Specialty facilities’ unique HVAC requirements include: field-heating systems, food-service condensing equipment, kitchen grease-exhaust duct, ventilation systems for beer keg rooms (carbon dioxide "beer pump" systems), and addressing the need for service corridor garage-ventilation systems for occasional vehicular traffic inside the facility. Christman: We frequently work on theme park attractions where the HVAC systems become part of the show. We have created unusually cold or hot spaces that are consistent with the story being told in the space. In other cases, we have had to design special exhaust systems to quickly reset the air quality in a guest space. In one example, we designed a system the clears the air of a fog effect that completely immerses a 900-seat theater in less than 2 minutes, before the next batch of guests arrive.

Hart: An ice arena is a special breed of building where not only temperature but also humidity must be managed on a very large scale. Arena humidity levels need to remain lower than a normal building whenever the ice is down and exposed. This is to prevent condensation and frost from forming on the ice or other surfaces as well as to maintain good ice surface conditions for players. In most climates, this may necessitate the use of desiccant dehumidifiers to achieve the desired goals.

Lancashire: One unique requirement that sports facilities have that other buildings wouldn’t necessarily encounter is the relatively sudden occupancy of a large space and the need to have that space at target environmental conditions by the time of the event. Where a typical building would operate its HVAC systems throughout a scheduled day, a sports arena goes from near-zero occupancy to 100% occupancy in about an hour. This requires the design of systems that can operate under low-occupancy conditions and then ramp up quickly, preconditioning the space in time for fans to arrive.

CSE: Have you specified distinctive HVAC systems on any such facilities? What unusual or infrequently specified products or systems did you use to meet challenging HVAC needs?

Hans: In the majority of sports arenas and theaters, the occupancy of the facility fluctuates dramatically with practices and rehearsals versus games and events. We recommend a high-performance building envelope to minimize the building load and increase the amount of time the HVAC systems operate at part load, typically greatly increasing the actual efficiency of the system. When the building is minimally occupied, the system needs are very low for ventilation, heating, and cooling. During an event or game, carbon dioxide (CO2) levels will rise and the demand-control ventilation system introduces more outdoor air to the space as the heating and cooling requirements are significantly increased. Providing a dedicated outdoor-air system (DOAS) system with neutral air direct to spaces allows for independent control of ventilation and temperature requirements. Also, providing multiple units with cross-ducting allows for better control at part and full load to maintain a comfortable environment within the ASHRAE 55: Thermal Environmental Conditions for Human Occupancy requirements for temperature and humidity.

Skoug: As a design-assist partner, we have reviewed the application of fabric duct systems and are encouraged by the ability of these systems to reduce overall installation and system-balancing efforts.

Christman: When designing HVAC systems for theaters, acoustics and guest comfort are paramount. We have designed special "plaque" diffusers to silently deliver large quantities of air into a theater space. These diffusers fit seamlessly into surrounding theming. We also use different desiccant systems to address the latent load on very high-occupancy spaces.

CSE: Describe situations in which you designed for specialty acoustics. What was the challenge, and how did you resolve it?

Lancashire: We design many TV studios, which bring their own set of challenges. Acoustics and vibration consideration is paramount to providing HVAC systems that can handle heavy internal loads (especially from studio lighting) while also being silent to the degree that high-end microphones will not pick up any HVAC noise. Oversizing of ductwork and dynamic isolation of all rotating mechanical equipment is critical to meeting these load and acoustic requirements.

Esarey: We will put forth a study to determine the envelope of a building. Generally, we try to design our HVAC systems to be acoustically sensitive. This can include strategies such as oversized ductwork and creative routing. We are able to solve acoustical issues through mechanical design as opposed to simply using silencers. This reduces overall cost. For example, in a recent project, a specialty acoustical consultant deduced that an estimated 30 silencers would be required for the project. We were able to achieve the same acoustic results with merely two.

CSE: Have you specified variable refrigerant flow (VRF) systems, chilled beams, or other types of HVAC systems into one of your specialty structures?

Lancashire: We have incorporated VRF systems into the design of one minor league ballpark. We used VRF for the heating and cooling of the suites in the ballpark. The owner was concerned with operating costs, so we went with a higher-efficiency system for these areas. While the systems have worked great, the one challenge we had was in the location of the condensing units in an area of the park that was not accessible to the public yet still in proximity to the suites.

Esarey: We have specified VRF and chilled beams in our specialty structures. However, for most of the structures we have done, they are not a system of choice. These systems provide their best performance in spaces with high internal loads or that need multiple-zone control in a small area. The typical specialty structure, whether performance venue or athletic facility, will generally see the exact opposite, with large spaces dominated by high people loading and humidity-sensitive environments. As a result, these are the exact spaces that chilled beam and, particularly, VFR should be avoided.

CSE: What types of DOAS are owners and facility managers requesting to keep their facility air fresh?

Esarey: DOAS seem to be integral in most of our specialty structure designs. Controlling temperature and humidity in these spaces is a challenge, particularly under the variable-loading characteristics that are common in these spaces. A properly integrated DOAS provides the tools to effectively control temperature and humidity under multiple loading conditions, delivering some of the biggest gains available to the client in energy efficiency.

Christman: In most cases, the DOAS we specify in theme park applications are direct-exchange (DX) units with hot-gas reheat or chilled water with wraparound heat pipes.

CSE: What types of air balancing or environmental balancing do you include in your design?

Skoug: For air duct distribution systems that are difficult to obtain future access to, we used mock-up testing to determine system prebalance on HVAC air-distribution devices. Then, final balancing was achieved with minimal effort.

Christman: For a recent large dark-ride project, we had to use air balancing to maintain a slight negative pressure, which contains a fog effect and prevents it from spilling into the adjacent ride scenes. Additionally, we often use positive building pressurization to discourage unconditioned, hot humid air from entering spaces where facility operations prevent exterior building doors from being normally closed.