In many aspects, the LAV and other similar system concepts are simpler, smaller, and less expensive than traditional HVAC systems. But from a control standpoint, they are much more integrated and complex than present day systems. These new HVAC system configuration concepts need to be implemented as a system, not through the one-of-a-kind piecemeal component-by-component configuring process that is used for most HVAC systems today. This is perhaps the greatest challenge and obstacle to getting such ultra-efficient HVAC systems in buildings because it requires a change in the process that manufacturers, designers, controls integrators, and even building operators currently employ to design, procure, construct, and operate buildings.

The approach also requires interdisciplinary coordination through design, construction, and into operation to ensure  actual space loads do not exceed design levels. Integrated design processes are not new, but the integrated effort must be much more rigorously applied through the entire building life cycle to be successful with LAV systems.

The benefits are substantial. Distributing both ventilation and individually adjustable thermal conditions directly to each occupant guarantees a fresher and more comfortable environment for all. And the energy implications are enormous. With LAV, one could today design and operate office buildings with vastly improved comfort and air quality that consume under 10kWh/sq.ft. (less than 35,000 BTU/sq.ft.) total energy annually.

In a few years this energy requirement is expected to fall to as low as 5 kWh/sq.ft. annually. Or, in newer terminology that I’d like to see used, office buildings will soon be able to operate at less than 0.5 kWh /occupant-hour. The transformation from VAV to LAV technologies will fully satisfy society’s need for the level of sustainable buildings envisioned for this century and can be part of an effective retrofit strategy for existing buildings. But such a transformation will challenge our industry’s desire and ability to adapt new practices throughout the design, construction, and operation phases to ensure it works correctly over time.

At this point the industry needs to learn more about these developing HVAC concepts, showcase them in example buildings, and ready ourselves to work together to make this necessary HVAC system transformation successful!

I invite your thoughts, comments, and good ideas about this article. Please contact me at thc@hartmanco.com.

 

Thomas Hatrman, P.E.

An internationally recognized expert on the use of advanced building controls and control networks, Thomas Hartman, PE, is the principal of The Hartman Co. in Marysville, Wash. He holds several patents for efficiency and comfort-enhancing technologies and has been a member of the HPAC Engineering Editorial Advisory Board since 1991.