Thermal Comfort

When it comes to creating a school building that is thermally comfortable, accommodating to daylighting and sun, and efficient to operate, the focus often moves from a well-designed building envelope to an efficient cooling and heating system. While mechanical engineers are quite good at figuring out the sizing, efficiency, and economics of different systems, architects are usually more concerned with flexibility in design, quiet operation, availability of indoor unit styles, and being able to modify the systems as needs change during the design or life cycle of the building. From all points of view, variable refrigerant flow (VRF) systems have become a popular choice to provide educational buildings with design flexibility and efficient, personalized comfort for occupants. Because they can be customized and easily zoned to provide cooling or heating simultaneously throughout a building, they meet the needs of a wide variety of spaces, including classrooms, lecture halls, administrative offices, athletic facilities, and more.

Design teams who have incorporated two-pipe VRF systems have found them easy to design, while facility operators find them easy to manage and modify as building needs change. Routine maintenance is minimal and limited to indoor unit filter changes and outdoor unit condenser coil cleanings. With this ease of design and installation, minimal required maintenance, superior energy efficiency, and long-lasting equipment, the systems’ total life-cycle costs are less than many others. More importantly, the capability of precise zoning gives individual control to teachers and administrators, keeping virtually everyone comfortable and content. From an operations standpoint, cooling and heating can be utilized in areas that need it, without paying for those that don’t.

The quiet nature of VRF systems makes them ideal for environments like libraries, classrooms, and study halls, where students need to focus without the distraction of noise. Indoor units operate down to 19 dB(A), quieter than a whisper, and outdoor units featuring high-performance compressors operate at levels as low as 58 dB(A). Energy recovery ventilators (ERVs) can also be applied to exhaust outside air and rid the school of toxins, odors, bacteria, and other potentially harmful contaminants. They also improve HVAC system efficiency by preheating or cooling incoming outside air with energy recovered from the exhaust air.

Nichole Watring is the principal at St. Joseph School in Pilot Grove, Missouri, where VRF systems have been successfully installed. She notes, “We have not had any issues with the system, and the teachers and students love that they can control the temperature of their rooms. It’s much quieter and more efficient than the previous system. The students especially love the burst of cool air when they come in from recess on hot days.”

Kevin Miskewicz, director of commercial marketing for Mitsubishi Electric Cooling & Heating, is always glad to hear success stories like this, as he points out, “We understand the challenges educational facilities face—particularly tight budgets, the need for individualized zone control, and high-efficiency demands. Working together, we can help design the right HVAC system that satisfies their unique requirements.”

Photo courtesy of Studio 804

Variable refrigerant flow (VRF) systems can be used in very energy-efficient buildings to provide thermal comfort and integrate with other mechanical systems within a building.

CASE STUDY: VRF SYSTEMS

Photos courtesy of Studio 804 (right) and Mitsubishi Electric Cooling & Heating (left)

Project: Johnson County Community College, Galileo Pavilion
Location: Overland Park, Kansas
Architect: Studio 804, Lawrence, Kansas

The Project: In 2009, Johnson County Community College (JCCC), which serves about 20,000 students, formed the Center for Sustainability to promote an environmentally, socially, and economically responsible campus. This commitment to sustainability has affected every building project on campus, including Galileo’s Pavilion, a new 3,000-square-foot academic building.

The team at JCCC had recently read an article about Studio 804, a not-for-profit 501(c)(3) in Lawrence, Kansas, comprised of graduate students at the University of Kansas (KU) School of Architecture, Design, and Planning. Each year, these students design and construct a technologically sophisticated green building under the direction of Dan Rockhill, distinguished professor of architecture at KU and the founder and executive director of Studio 804. The organization was a strong match for JCCC’s vision, so the school contacted Studio 804, and they agreed to work together.

The Design Approach: “We designed Galileo’s Pavilion—its two classrooms, lounge, and exhibition/display space—using our current knowledge of sustainable design,” Rockhill says. “We took advantage of the daily and seasonal cycles of nature to passively cool, heat, and daylight the building, as well as supply electricity and utility water. We planned rainwater harvesting, green roof trays, photovoltaics, and a wind turbine to further reduce or even eliminate the need to use public utilities.”

When it came to selecting an HVAC system, Rockhill says, “We basically had three distinctly separate spaces. Although they’re in the same building, the loading on them is different. So that resulted in us needing three separate air-conditioning and heating solutions” – or, zoning. Efficiency was paramount as well: “We pride ourselves on being able to promote sustainable everything, so HVAC is no exception. VRF was the clear choice since we wanted to demonstrate the most technologically advanced equipment in the industry. VRF and its capacity to simultaneously cool and heat all of the spaces within the building was a fit.”

The Solution: A solar array of 44 photovoltaic panels and a 2.4-kW wind turbine installed on the site now produces about 70 percent of the building’s energy. HVAC loads are reduced through occupancy sensors, LEDs and fiberoptics, and a lighting control system. “The school monitors the whole thing through our building automation system,” explains Michael Rea, JCCC’s sustainability project manager. “The VRF system is integrated into that. So we can see humidity or change set points, for example.”

The Results: Rea points out, “Everything with the VRF system has been going well. No compressor failures, no leaks, no fan problems, nothing. Our maintenance is easy too—just changing the filters and making sure the condensers are clean.”

Another sign of success: LEED Platinum certification. Rea says, “For us in the Center, we were excited to get something above Silver, our current standard. Galileo’s Pavilion is a showcase about what a sustainable building can be on a campus. We were also honored to receive the 2013 CSI Kansas City Chapter Innovation in Sustainability Award for the building.”

The professors involved are happy too, saying, “The students leave wondering why other buildings don’t have the features this one does. And so in that sense, Galileo’s Pavilion is perhaps the crown jewel of Johnson County Community College’s green portfolio.”

Interior Space Flexibility

Collaborative teaching and group learning are concepts in education that have received a lot of attention and investigation in recent times. Whether school boards or educators are aware of current research topics or not, they often request architects to consider ways to incorporate spaces that can be flexible and transformed in size and character. Of course, that has to be easy to do and still allow for the spaces to function in terms of light, views, and acoustics. After all, the goal is to enhance teaching and learning, not detract from it.

One of the solutions being used increasingly in schools is operable glass walls made of panels that can be easily moved to define smaller spaces when they are closed and larger spaces when they are open. From a learning perspective, this solution allows the creation of defined areas for focused learning or the opening up of larger common areas where multiple students can work together on a range of activities utilizing shared resources, such as technology centers or presentation areas. Not only does this approach offer the sought after variety for student programming, but it also means that teachers can support each other, fostering a better-managed classroom environment. From an overall design perspective, creating such a flexible classroom configuration with operable glass walls can optimize or even reduce the needed floor space within a building envelope, which can translate into reduced construction costs.

Taking this flexible-space approach to the design of school environments can contribute to the following common requests from educators:

• Variable-sized group work: Operable glass walls enable separation of smaller groups for discussion, group projects, quiet zones, advanced or remedial work, test centers, teacher assistant-led groups, etc.
• Multiple concurrent activities: This approach allows teachers to monitor multiple activities in separated spaces.
• Outside volunteer space: When a parent or visitor volunteers in the classroom, they can use this area to work independently with students.
• Shared resources: Flexibly accessed glass walls offer common storage space for shared books, supplies, computers, and reduces redundant purchases.
• Teamwork: Joining two or more classrooms with shared space allows teachers to configure space to meet their needs, while advanced operating mechanisms allow for quick and easy transformations.
• Class management: One teacher can temporarily monitor two classes if another teacher has an emergency or needs a break.
• Minimized visual distractions: Use of mixed transparent glazing in the upper portion of the glass wall and opaque glazing in the lower portion allows seated students to be isolated from excessive distraction beyond the wall, while a standing teacher can monitor multiple spaces.
• Cool off/recovery area: This offers isolated, private space for behavioral and emotional issues or disciplinary actions.

Architects who have used this approach include John Brown, AIA, partner, Hollis + Miller Architects, who points out, “Connectivity, flexibility, and visibility were all very important concepts in the design of the spaces within our school projects. While we still needed the capability of closing off spaces for more traditional classroom and learning spaces, we also needed to open up the walls to accommodate larger groups, which would then allow for collaboration.” David T. Esely, AIA, senior project architect of the same firm, adds, “When closed, very little sound penetrates, which allows for diverse learning opportunities on both sides of the panels simultaneously. When the panels are open, the opportunities within the space transform and can then be tailored to specific instructors’ needs and requirements. This is all done with ease, speed, and frequency.”

Photo courtesy of NanaWall Systems

Operable glass walls used in school settings allow architects to create flexible spaces that can meet a variety of educational needs and preserve the light, sound, and control aspects of design.

CASE STUDY: FLEX SPACE IN SCHOOLS

Images courtesy of NanaWall Systems

Project: Burleson Elementary
Location: Dallas
Architect: SHW Group

The Project: The architecture team at SHW Group was hired to work on eight new elementary schools built in the Burelson, Texas, school district. One of the overriding design criteria from the school district was the creation of flexible spaces that could readily accommodate smaller or larger groups of students. In particular, there was a requirement that two classrooms share a common multipurpose room.

The Design Issue: Classroom flexibility is a 21^st century necessity. In the past, multipurpose rooms were often designed as separate classrooms—and sometimes located in a different part of school or with a “garage door” type of overhead partition. “The multiuse space needed great visibility and flexibility, with good acoustic separation,” says Konrad Judd, AIA, lead designer at the SHW Group in Dallas. Judd describes his experience with designing a flexspace system in the Burleson School District as “education delivery into the 21^st century with a more flexible learning model.”

The Design Solution: Operable glass walls were selected since they provide a range of effective solutions for the design of new classroom space, adding flexibility while increasing interior visibility, safety, and security. Operable glass walls also synchronize with the problem-based curriculum revolution taking place in schools, while controlling costs for added facilities and classrooms.

The SHW Group designed the Burleson flex rooms to mesh with teaching methods that promote active participation, self-direction, and interest group clusters. Once the common wall is removed between classrooms, teachers and students have access to flex spaces. To do this, SHW Group used a V shape in the floor plan to cut into the traditional rectangular space of the existing rooms. By making three rooms out of the space normally utilized for two rooms, SHW decreased the costs. Judd points out, “The multiuse space that we designed to adjoin two classrooms needed great visibility and flexibility with good acoustic separation. The operable glass walls maximize the view and flexibility of the space when closed or open.” The 15-foot-tall operable glass walls have horizontal mullions dividing the clear glass portions from the opaque lower panels.

The operable glass wall systems are utilized in eight schools within the district, creating a smaller building footprint for each individual school and saving on building operations costs. Each wall has a swing door option for traditional classroom access.

The Results: The operable glass walls have excellent sound attenuation but also maximum transparency so teachers can use the flexible space for group work, exam makeup, discipline intervention, or independent study. Moreover, the three classrooms can become one space, which allows for unlimited interactions and creative lessons. The resulting flexible spaces allow two teachers or groups of students to collaborate on different projects or lessons.