COVID, sustainability, energy efficiency drive college building design
Colleges and universities have been sustainability trendsetters over the past several years. COVID-19 has required designers to think differently about building sustainably
- Kim Cowman, PE, LEED AP, National Director of Engineering, LEO A DALY, Omaha, Nebraska
- Daniel S. Noto, PE, LEED AP, Owner, Noto Consulting Group LLC, Roswell, Georgia
- Coral Pais, PE, BEMP, LEED AP BD+C, WELL AP, Mechanical Engineer, DLR Group, Cleveland, Ohio
- John M. Rattenbury, PE, LEED AP, Vice President, Cannon Design, Boston
- Luke Richards, PE, Project Engineer, RMF Engineering Inc., Raleigh, North Carolina
- Simon Ubhi, PE, LEED AP BD+C, Principal, Henderson Engineers, Los Angeles
- Toby White, PE, LEED AP, Associate – Boston Fire and life Safety Practice Leader, Arup, Boston
What level of performance are you being asked to achieve, such as WELL Building Standards, U.S. Green Building Council LEED certification, net zero energy, Passive House or other guidelines?
John M. Rattenbury: At a particular campus I am familiar with, the owner is expecting all capital projects to meet LEED certified at a minimum and even small space alterations within buildings are being designed to meet LEED Interior Design and Construction (ID+C) performance prerequisites and strategies.
Luke Richards: The majority of our higher education clients are requiring facilities to be certified by either the U.S. Green Building Council or the Green Building Initiative (GBI). The minimum standard being a LEED Silver or a two-Globe certification, although we have seen a shift to higher requirements with private clients. Our most recent project nearing construction and certification completion is a classroom building with education laboratories for a community college in Raleigh, NC. The sustainability requirement was for a two-Globe certification. Our building MEP design was able to expand an existing efficient campus heating and cooling plant, implement water use reduction through the installation of water-efficient/low flow fixtures and reduce overall energy consumption through energy recovery systems and building control strategies such as demand control ventilation and economizer operation.
Kim Cowman: Many times, we are finding higher education campuses have their own sustainability master plans and requirements to follow. These may have many similar elements to other sustainability standards such as LEED and WELL but are tailored to the campus specifically. We are also seeing a focus in reducing not only energy consumption but overall carbon emission reductions for campuses. These requirements lead to the electrification of building designs or the moving away from using fossil fuels for heating and cooking applications. Incorporation of renewable energy systems such as photovoltaic systems further improve carbon emission reductions for a campus. As with any construction project, budget limitations still warrant payback and life cycle analysis of all systems and potential renewable technology incorporation. Where projects budgets may not be able to sustain incorporation of renewable energy systems as part of the initial budget, evaluating design considerations to provide future connection capabilities is important.
Simon Ubhi: LEED is still the most common standard encountered to date, though WELL is coming up more frequently. The rise of WELL could be attributed to building occupants becoming more aware of how their building impacts their health and well-being. WELL emphasizes occupant health and overall well-being. LEED remains a common standard given its history in the industry and focus on the site/location, building construction, water use and energy consumption.
Coral Pais: Some campuses still have minimum LEED targets for buildings which remains the most widely recognized sustainable rating system. But there are educational institutions that recognize that there are other rating systems that can create a robust framework for the application of project-specific sustainable design strategies — these include Living Building Challenge or Fitwell.
What unusual systems or features are being requested to make college and university projects more energy efficient?
Kim Cowman: With the move toward carbon emission reduction and electrification we see more evaluation and consideration of heat pump technologies such as geothermal heat pump systems, chilled beam technologies coupled with a geothermal heat recovery chiller and VRF systems with heat pumps.
Simon Ubhi: Flexibility of the space is one which adds a design challenge to projects. This requires the mechanical and electrical systems to have built in capacity to allow this capability. This can lead to more efficient space use and could potentially allow reuse of space rather than additions or demolition and reconstruction. A handful of universities have transitioned their design standards to adopt full building electrification and more are likely to do so in the near future. This signals that higher ed clients are recognizing that the continued use of fossil fuels is not aligned with their climate pledges. Heat pump technology is also something we’re seeing more and more of to address both efficiency and all-electric building strategies.
What types of sustainable features or concerns might you encounter for these buildings that you wouldn’t on other projects?
Simon Ubhi: Air change rates and exhaust are ones which present unique challenges. The intermittent use of lab space and exhaust hoods by researchers, instructors and students makes control of systems and prediction of energy consumption quite difficult. This is further complicated when the lab’s final use is either unknown, undetermined or may change over time. This impacts the level of exhaust and potential hazards/chemicals in those exhaust streams. The move to all-electric buildings actually reduces some concerns associated with exhaust and combustion gases. Water heating strategies become somewhat of a concern in all-electric buildings, but hybrid heat pump solutions are becoming more and more common.
Luke Richards: We have been specifying an increased amount of wrap-around heat pipes within large 100% outdoor air units supplying ventilation for laboratories to meet local energy code requirements. Our climate zone in the Southeast requires the dehumidification of outdoor air most of the year, requiring supply air to be conditioned to between 50°F and 55°F independent of space temperature requirements. As most laboratories are designed for fixed air change rates, supply air must be reheated to avoid overcooled indoor spaces. Historically, this has been done using hot water or electric reheat coils within ducts or air terminal units, further contributing to energy usage. The wrap-around heat pipe can sensibly pre-cool incoming outdoor air to reduce the enthalpy within the air being supplied to the cooling/dehumidification coil. The energy absorbed by the refrigerant within the heat pipe causes it to evaporate and travel within piping to another coil downstream of the cooling coil without the use of additional pumps or compressors. The conditioned air is passed through the downstream coil causing the refrigerant to condense and release this heat energy back into the airstream as free reheat.
What types of renewable or alternative energy systems have you recently specified to provide power?
Simon Ubhi: Photovoltaic canopies over parking garages have been successful. In new construction, the challenges are limited. In retrofit situations, the challenge typically emerges in coordinating the structural design to support the system.
What are some of the challenges or issues when designing for water use in such facilities, particularly campus buildings with high water needs?
Simon Ubhi: When the use of the lab space is either unknown or undetermined it makes it difficult to assess potential water use. The lab use may also change over time, which impacts consumption as well as the types of contaminates that will impact water quality from waste lines. Other water uses for either restrooms or HVAC (cooling towers) is fairly similar to other occupant use types.
How has the demand for energy recovery technology influenced the design for these kinds of projects?
Luke Richards: There has been an increased demand for energy recovery, whether for laboratories or other building types. This demand is due to increased ventilation requirements combined with energy efficient goals. Today, systems such as energy recovery wheels can be installed in commercial grade packaged HVAC units. This has driven down the installed cost of air-to-air energy recovery where, before, systems would have to be custom built.
Simon Ubhi: Energy recovery is complicated by the use of the facility and the contaminates that are likely to occur in both the air and water waste streams. While abrasive/caustic contaminates can be worked around with run-around coils for air-side energy recovery, there is a corresponding loss in recovery efficiency due to this solution’s use.
What value-add items are you adding these kinds of facilities to make the buildings perform at a higher and more efficient level?
Simon Ubhi: Smart controls for building occupancy is a big factor in performance. This includes lighting, comfort conditioning and ventilation. All are significant contributors to building energy use and thus the need for tight integration between uses and active systems within the building is important for efficiency operations.
How have energy recovery products evolved to better assist in designing these projects?
Simon Ubhi: More resistive materials or ones better suited to enable heat transfer help recover energy that would otherwise be exhausted or removed from the building. Any energy that can be recaptured, reused or repurposed helps the building performance and reduces new energy, which must be added from the grid or renewables.