David Sellers

Field Lessons in HVAC Physics, Physiology, and Psychology
May 31, 2007

If you go out and operate a building for a while, you will soon discover that human physiology and psychology are inextricably interwoven with the design, construction, commissioning, and operation of its HVAC systems. At their most fundamental level, HVAC systems are real time science experiments in applied physics; hardware moves, fluids flow, temperatures and pressures change, and occasionally, things fail to work as intended or simply fail. But, interestingly enough, HVAC systems are also real time experiments in physiology and psychology and, like any other science experiment, they have their share of successes and failures in these arenas as well.

Physiology is there because at their core, the systems we develop and operate are intended to provide comfort and safety for the building's occupants; i.e. the are intended to provide an environment that supports the "functions and activities of life or of living matter".

Psychology has a big role to play too. When I teach, I often reference an old joke I once heard that asks:

      How many psychiatrists does it take to change a light bulb?

The answer is:

      Only one, but the light bulb has to want to change.

In my experience, for a building and its systems to succeed at their intended function, everybody has to be dedicated to that goal.  And the word everybody encompasses a pretty large body of humanity; from the design team to the construction team to the operating team, with the owner and building occupants closing the circle.  The goals of the design team are typically set by the needs of the owner and occupants, and the project will only be successful if in the end, those goals and needs are met. 

The path between the beginning and the end has its foundation laid not only on sound engineering principles, but also on using those principles to meet the physiological and practical needs of the occupants.  Herding all of the cats down the road to success requires applied psychology - the "science of mind and behavior" - in addition to the practical knowledge associated with fabricating structures and systems.

By its nature, my occupation as a commissioning engineer takes me out into the field a lot. As a result, I am presented with a lot of lessons, some of which can be sobering, some of which can be amusing, and all of which involve more than engineering principles. Every week, I learn something new:

• Diagnosing a problem may reveal a phenomenon I have not encountered before or deepen my understanding of something I am already familiar with.
• Answering a question from an attendee at a lecture or training session may raise questions of its own and send me off to discover answers and resources.
• Resolving a problem may expose me to "people problems" that require "people skills" that I have not called on before if I am to succeed.

Ultimately, I think it’s the interwoven nature of the business - the mingling of engineering dynamics with human dynamics - that makes it so interesting and challenging.  Towards that end, I hope to share these experiences with you in this blog by opening the door not only to the things I'm learning out there in the field each week but also the door to the things you are learning.  By sharing lessons, insights, and resources with each other, we can open the doors to discussion and greater understanding and all learn something; especially "yours truly" who until a couple of months ago though a blog was a sort of swampy area in northern Scotland.

Check back in a few days and I'll share something I learned recently about damper performance where theory didn't match reality in a test I performed with several colleagues at the Pacific Energy Center.

Posted by David Sellers on May 31, 2007 | Comments (3)