Building Energy Resilience

When you’re asked to review someone else’s building automation system (BAS) programming, it’s a bit of a daunting task.  This is because those of us who program building systems (or really any computer-driven system) for a living figure out that there are a million different ways to capture the same process in any given programming language. Usually no two people will do it the same way.

Recently there has been a lot of talk resurfacing about what defines an "open system."  It is a concept that has been debated and sold for well over a decade in the HVAC automation industry.  There still seems to be some ambiguity about what this really means.

I’ve noticed a common problem across a range of buildings due to the idea that all PID controls behave the same.  The result of this misconception rears its ugly head in poor tuning and poor implementation of PIDs that can cause your HVAC system to perform poorly for years.  The PID is a great means to realize your design intent, if you know how to properly spell out for your controls contractor what it is you’re looking for.   But before that, let’s get the basics down first - What is a PID?

You might have heard of Maslow’s hammer, that old adage “I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail.” In my experience I’ve seen the practice of outside air temperature (OAT) reset, which is shorthand for a method by which building systems are “primed” to deal with real-time outdoor air conditions, treated as that hammer. I’ve found it in the common sequence of operations (building technology speak for the computer programs which make building systems operate) designed to control everything from supply air temperature from a VAV box, to resetting the valve positions on fin tube radiation zones.

Recently I wrote a Building Management System (BMS) controls specification for a customer who needed a controls upgrade. It was an excellent opportunity for me to flex a new engineering perspective and see what energy savings I could squeeze out by retrofitting an existing mechanical system with a new control system. When it came to the sequence of operations, I decided to consult ASHRAE Guideline 36.

Recently I have performed new construction commissioning services on a project with a job specification document that was over 1200 pages in length. As you can imagine, it was very comprehensive. However, I found that it was comprehensive in all the areas that it didn’t need to be, and not specific enough where it mattered.

Building automation systems (BAS) have been around since the 1980s. They, like any other computer based technology, have evolved several times over parallel to the widespread adoption of information systems across all industries. Their key benefits are understood to be primarily HVAC system control, automation, and HVAC system optimization. But with the advent of systems being more distributed and more open over the last decade, there has been one benefit that gets overlooked a lot: BAS trend data.

Modern web-accessibility of building control systems is both a blessing and a curse. It is a blessing if you’re the facilities manager and you live an hour away from the building you’re responsible for and there is a problem in the middle of the night. Simply fire up the ole home computer, connect to your building, issue a few overrides, clear an alarm, go back to sleep and deal with it in the morning. So what’s the downside?

Wireless networks are everywhere in 2014. I have on my person 3 wireless networks happening at any given moment (4G LTE, Bluetooth, and Wi-Fi). I am a walking source of radio everywhere I go. And this is only the beginning. As more wireless devices proliferate for personal and commercial use, the spectrum will only grow more crowded and complicated. Are you prepared as wireless technology penetrates the HVAC automation market? Do you understand how radio propagates with respect to data and networks? I hope to scratch the surface and share some of this with you in the following paragraphs.