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

Nedzib Biberic, PAE
Kyle Frennea, PAE

Four-Pipe VAV systems are complex and intelligent, leveraging common HVAC system components to minimize the energy used to condition outside air and reheat air at terminal equipment. Oregon State University's Johnson Hall, a 58,000 square-foot chemical and biological laboratory and office building on the central campus that opened in September 2016, uses this system to great effect.

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, successfully 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.

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 and advice for future projects where designers may consider using this sustainable and manageable system.

Learning Objectives

  • Develop an understanding of 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 an entire building rather than small pieces;
  • Use actual energy usage as proof that this system works to validate implementing this system design in similar buildings; and
  • Overcome nuances and avoid pitfalls of the modeling effort via our model validation lessons learned.


Nedzib Biberic is a skilled engineer with 15 years of experience. 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 innovative approaches to projects with stringent environmental regulations.

Kyle Frennea is a LEED Accredited Professional with 8 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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