ATLANTA - Night pre-cooling, naturally daylit areas, and low-emission HVAC systems are some of the sustainable measures selected by students as part of the American Society of Heating, Refrigerating and Air-Conditioning Engineers' (ASHRAE's) 2006 Student Design Competition.

This year's competition focused on the mixed-use renovation of the Dallas Power & Light building in a historic area of Dallas. The renovation includes converting the majority of the former office building into residential apartments, with retail space occupying the first floor of the building. Awards were announced in three categories: HVAC system selection, HVAC system design, and architectural design.

The winning entries in the HVAC system selection and HVAC system design categories have been awarded to the same team from Pennsylvania State University: Justin Bem, Kevin Kaufman, David Melfi, Jon Gridley, Jessica Lucas, and Yulien Wong. Their faculty advisor is William P. Bahnfleth, Ph.D, P.E.

For the HVAC system selection category, the students selected water-source heat pumps, giving the system a life cycle cost of $7,464,000. The system selected calls for water-source heat pumps to parallel the one rooftop unit serving floors two through 20 and an additional rooftop unit for the first-level retail area. This system allows for easily converting first-level retail space to a new function, limits maintenance disruption to individual apartments and the roof, and allows for separate metering of retail space.

The ventilation systems were evaluated using Standard 62.1 and on their ability to fit into available mechanical room and shaft space. The option chosen was a rooftop unit paralleled by WSHP for residential units, and a rooftop unit serving the retail areas. The students said, "The separation of the two types of spaces allows for better flexibility in the system and allows for future growth."

The system also allowed for lower cost and emissions as well while allowing the building to meet Standard 90.1 without compromising the historic integrity of the building.

For the HVAC system design category, the students designed a decoupled outdoor air system with a parallel sensible system with an energy cost of $4.72/square foot per year.

Because the mechanical penthouse on the second-floor roof of the annex was so close to the ground, dealing with architectural, environmental, and acoustical impacts were serious considerations. Some of the solutions the students used were: night time pre-cooling with unconditioned night air, and using only fan energy for the retail spaces to reduce cooling load during the day. The students also used a dedicated outdoor air system.

First place in the architectural design category has been awarded to Alissa Ogen and Sonia Carias of Savannah College of Art and Design. Their faculty advisor is Emad M. Afifi, Ph.D. The students, who were required to design a mixed-use collegiate space, designed a student activities center complete with student dormitories, a theater, recycling centers, an amphitheater, retail, landscaping, and dining space.

The entry's sustainable design features included pervious sidewalk materials, photovoltaic glass panels inside the cafeteria, translucent, diffuse light-transmitting walls, and reflective roofing materials. The students' design also includes a naturally ventilated atrium near the lobby and a naturally daylit cafeteria that is also shaded to save on energy costs.

Awards will be presented at ASHRAE's 2007 Winter Meeting, Jan. 27-31 in Dallas. Winning student groups will each have a poster presentation to display their projects at the meeting.

This competition recognizes outstanding student design projects, encourages undergraduate students to become involved in the profession, promotes teamwork, and allows students to apply their knowledge of practical design.

Publication date: 09/04/2006