Enhancing air quality and energy-efficiency for college campuses

HVAC insights

• HVAC designs for specialized spaces like auditoriums and sports facilities require tailored solutions to handle irregular occupancy patterns while maintaining energy efficiency and comfort. 

• Advanced systems such as VRF, heat pumps and energy recovery units are effective for increasing energy efficiency in challenging climates and existing buildings.  

Respondents:

• Matthew Goss, PE, PMP, CEM, CEA, CDSM, LEED AP, MEP + Energy practice leaders, CDM Smith, Latham, N.Y.
• Abdullah Khaliqi, PE, CPQ, Academic market leader, Fitzmeyer & Tocci Associates, Inc, Woburn, Mass.
• Stephanie Lafontaine, PE, LEED BD+C, Lead mechanical engineer, RMF Engineering, Boston
• John Mongelli, PE, Associate, Kohler Ronan Consulting Engineers, Danbury, Conn.
• Jeff Wurmlinger, PE, HDR, Mechanical Section Leader, Pheonix

What unique heating or cooling systems have you specified into such projects? Describe a difficult climate in which you designed an HVAC system for a college or university project.

Abdullah Khaliqi: For college and university projects, we have specified unique heating and cooling systems such as variable refrigerant flow (VRF) systems and advanced heat pumps. In challenging northern climates with design temperatures reaching 0 F or below, VRF systems are particularly effective. They provide efficient heating and cooling while adapting to varying loads. Heat pumps, combined with VRF technology, offer reliable performance and energy efficiency in these harsh conditions, ensuring consistent comfort and operational efficiency. 

For existing buildings, what HVAC, outdoor air, UV-C, bipolar ionization or other indoor air quality strategies are you designing?

Abdullah Khaliqi: For existing buildings, we focus on advanced filtration systems as the most important aspect of improving indoor air quality. High-efficiency filters, such as HEPA, are commonly integrated to capture particulate matter. Additionally, strategies like increasing the percentage of outdoor air can be implemented to enhance ventilation. UV-C and bipolar ionization technologies are also considered to help in reducing airborne pathogens, though they are not widely utilized currently. These measures collectively improve indoor air quality and contribute to a healthier environment.  

John Mongelli: For existing buildings, we often utilize a dedicated outdoor air system to treat ventilation air. This allows us to keep the ductwork distribution throughout the building at a manageable size to accommodate existing conditions. In some cases, we will use UV lighting on the unit cooling coils to prevent bacteria and biofilm from building up on the coil. We have used bipolar ionization on projects with very strict energy goals and in certain applications, like gymnasiums that have large swings in occupancy. 

Jeff Wurmlinger: Renovation projects can be significantly more challenging than most new construction. These challenges often arise from the physical constraints of updating a space built in a different era or for a different function while needing to meet modern design standards and codes. This can limit the system options available to improve indoor air quality. While various technologies exist and are sold as solutions to improve indoor air quality, a thorough understanding of the project goals is essential to determine the best approach.  

Strategies may include implementing newer technologies, including bipolar ionization or UV-C, each of which comes with inherent challenges and should not be broadly applied to all designs. For instance, UV-C installations require consideration of line-of-sight and sufficient dwell time (exposure) to provide any benefit. Ionization methods work well on organics but also have their limitations and initial capital costs. Transitioning a space from an overhead mixed HVAC design to displacement ventilation can significantly improve indoor air quality without additional technology. However, increasing the outside air volume will improve air quality while also increasing the amount of energy used for conditioning.  

How have you worked with HVAC systems or equipment design to increase a building’s energy efficiency?

Matthew Goss: On various energy efficiency projects, we have incorporated pressure-independent control valves (energy valves), variable frequency drive (VFD) technology and various building management and automation system components, such as demand control ventilation, temperature reset and CO2 monitoring. 

Abdullah Khaliqi: To increase a building’s energy efficiency, we integrate VFDs into HVAC systems if they are not already included. VFDs adjust motor speeds to match demand, reducing energy consumption. Additionally, we design the most energy-efficient systems possible, utilizing high-performance equipment, optimizing system controls and incorporating advanced technologies like smart thermostats and demand-controlled ventilation. This approach ensures that the HVAC system operates efficiently, minimizes energy use and supports overall sustainability goals.  

John Mongelli: We have performed renovations to a campus laboratory, the original construction of which dated back to the 1970s. We found the building to be over-ventilated for its current function; it utilized 100% constant volume outdoor air systems. We redesigned the systems to reduce outside air from 12-15 ACH down to 8-10 ACH, and we added variable air volume systems with energy recovery to result in significant energy savings.  

Jeff Wurmlinger: One of the first stages in a building renovation project is to take a holistic view and understand where potential energy balances exist. This can involve loads within the building or waste heat streams from adjacent buildings or utilities. A more balanced simultaneous heating and cooling demand gives a better chance to include heat pumps in the design. Another way to increase building efficiency is to determine if we can transition from an air-cooled to water-cooled solution.

If the project requires new mechanical infrastructure, we will also explore opportunities to operate the equipment at a better efficiency point. From a high-level perspective, this can be achieved by supplying warmer chilled water or with lower heating hot water temperatures. However, this approach requires a different understanding and consideration of additional methods for dehumidification, domestic water and heating. 

What best practices should be followed to ensure an efficient HVAC system is designed for this kind of building?

Matthew Goss: To ensure an efficient HVAC system design, some of the most important practices include incorporating energy modeling and whole-building simulation processes throughout the design phase. During construction, startup and operational lifecycles, commissioning, retro commissioning, testing and monitoring activities are crucial for maintaining a successful system.  

Abdullah Khaliqi: To ensure an efficient HVAC system design, best practices include adhering to ASHRAE standards and using a comprehensive system selection process during schematic design and conceptual design development. This involves evaluating the pros and cons of different systems, addressing owner needs and preferences and aligning with campus energy goals. Engaging stakeholders in these discussions ensures the chosen system meets efficiency targets and supports the building’s operational and sustainability objectives.  

John Mongelli: Interviewing the staff and building a rapport with the building owner are some of our best practices. It is important to understand the issues the owners experience, and it is hugely beneficial to know their operational strengths and weaknesses. From there, the engineers can design a system that is not only efficient and meets their day-one goals but also falls within their operational capabilities. At the end of the day, the building is only as efficient as the people you turn it over to.  

Jeff Wurmlinger: Do not approach any renovation project with a preconceived design in mind. We recommend conducting an initial study of the building or space(s) and their supporting utilities before generating any design options. It is important to involve the owner and facilities team to fully document all utility capacities for comparison against the project utility demands. For example, avoid pushing the use of chilled beam deployment without a thorough understanding of the building envelope for moisture control.

Having an intimate knowledge of the building or space(s) involved in the project and sharing all observations with the owners’ project team is imperative. Two major pitfalls can derail a renovation project. The first is the dreaded “unforeseen conditions,” often due to the lack of a destructive investigation (i.e., shaft walls) during the study phase. The second is the misapplication of a system type to the building or space(s). These can significantly challenge a project and, in some cases, may require substantial or complete redesign. 

How does HVAC and plumbing engineering address the needs of specialized spaces, such as auditoriums, libraries, and sports facilities in university buildings?

Abdullah Khaliqi: HVAC and plumbing engineering address the needs of specialized spaces like auditoriums, libraries and sports facilities by implementing tailored ventilation solutions and controlling humidity and condensation. These systems are designed to handle irregular occupancy patterns, with the capability to manage large capacity spikes efficiently while also operating at lower capacities when demand is reduced. This ensures optimal indoor comfort and performance while maintaining energy efficiency, which is crucial for minimizing operational costs and meeting sustainability goals.  

John Mongelli: These spaces need to be designed to accommodate potentially large swings in occupancy. HVAC systems need to be able to react promptly to adjust for occupant loads. Plumbing systems also have to be designed to accommodate the heavy demand that could occur during a sporting event, such as intermission and the usage of all the toilet facilities in a given moment. 

What unique HVAC systems have you specified for campus dorms? How do you help engage and educate the students with this design?

John Mongelli: Many of the dorms we design are provided with a dedicated outside air system, ducted to each dorm room for continuous ventilation air delivered at a neutral temperature. In addition to the ventilation air, a fan coil unit connected to either a VRF system or a chilled water/heating hot water plant is provided for each dorm room. Window sensors that automatically turn off the fan coil unit when the windows are opened have become common practice in our designs. 

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