Saving Energy With Four-Pipe VAV: A Case Study of OSU Johnson Hall

Nedzib Biberic, PAE
Kyle Frennea, PAE

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Four-pipe VAV systems are complex and intelligent, leveraging common HVAC system components to minimize the energy used to condition and reheat outside air at terminal equipment points. Oregon State University's Johnson Hall, a 58,000-square-foot chemical and biological laboratory and office, has used this system for over three years successfully, saving energy, operational costs, and providing ease of maintenance for the institution. The presentation analyzes the post-occupancy data alongside the innovative and, just as importantly, replicable mechanical design.

The unique four-pipe VAV system, operating in concert with zone-level laboratory controls, including VAV fume hoods, room pressure monitors, and airflow valves, allows for precise airflow and comfort control within each zone while optimizing energy use. This is done by coordinating outside air conditioning with zone demands minimizing reheat and humidification loads that are typically associated with the airflow-dominated chemical and wet labs of this type. In Johnson Hall, the infrastructure serving the laboratory HVAC system is seamlessly integrated with that of the non-laboratory spaces: four-pipe radiant systems are utilized to decouple ventilation and space heating and cooling loads. The consistency across the systems brings an ease of maintenance for the building operators.

This design approach for the academic building's mechanical systems relied heavily on stakeholder engagement, embracing uncertainty, and feeling comfortable with exploring different options throughout the process. This was done through and supported by extensive modeling data, from design to implementation. The significant success is a testament to the approach. Equipped with modeled and actual building energy use data from Johnson Hall to validate design decisions, the team will reflect on the system implementation process and share lessons learned for academic project owners, architects, and engineers demonstrating that whole-systems design thinking, ultimately lowers operational and maintenance costs and has an ease in maintaining the system, all while fulfilling, and overwhelmingly achieving, sustainability goals.

Learning Objectives

  • Develop an understanding and comfort with how and why to implement a zone-level four pipe VAV heating and cooling system;
  • Identify holistic solutions by applying innovative ideas to entire buildings rather than fragmented and/or small applications;
  • Review 3 years of Energy Use Intensity (EUI) data system validation for implementation of system design in similar buildings and laboratories; and
  • Overcome nuances and avoid pitfalls of the design effort from our lessons learned and with extensive, ongoing modeling.


Nedzib Biberic is a skilled engineer with 16 years of experience and a member of I2SL. He has provided expertise for more than three dozen sustainable projects requiring highly efficient system design and innovative engineering. Seventeen of his projects have achieved LEED ratings, three of them Platinum. Nedzib is an experienced energy modeler with extensive experience with laboratory and healthcare projects bringing unique approaches to projects with stringent environmental regulations.

Kyle Frennea is a LEED Accredited Professional with nine years of experience. He is a creative mechanical designer who seeks unique solutions that maximize energy, decrease maintenance and operations costs, and meet the owner's budget and schedule requirements. He brings to the table a wealth of knowledge about sustainable laboratory systems in both academic and healthcare settings.


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