Building Energy Resilience

In the mid-2000s, the late US Senator Ted Stevens (R-Alaska) famously used an analogy for the internet as a series of tubes. The full analogy was a bad one, and was concerning since it revealed to the tech savvy public how little the congressional entities in charge of creating policy actually understood the technology to which they were attempting to tailor policy. Incidentally, the needle has not moved much in this area in the intervening decade (crypto back-door arguments being a prime example), but that is a blog post for another time.

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?

Energy efficiency upgrades are widely recognized by facility managers as good investments with the potential for short payback periods and attractive lifecycle costs. However, energy efficiency investments are also often viewed as an added expenditure in competition with capital investments in infrastructure driven by end users and/or the mission.  Some managers may fear a tradeoff between energy efficiency investments and other improvements in building performance, such as better indoor environmental quality (IEQ) or lower maintenance costs. In my view, the tradeoff between energy efficiency investments and other improvements in building performance is a false dichotomy - energy efficiency investment opportunities can reduce costs while enhancing building performance to better satisfy end users and the mission. 

Variable Refrigerant Flow (VRF) systems are becoming an increasingly popular HVAC solution for commercial construction projects around the country.  They offer many benefits that can be realized by architects, engineers, contractors, and end users. Some of the benefits include energy efficiency, flexible installation, and local controls for end users. I began my career by spending two years as sales rep for a VRF manufacturer, and the following are some observations I made during that time about issues which commonly caused problems during installation.

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.

In a previous blog post, I discussed the efficiency opportunity for airflow setback in healthcare operating rooms (ORs). Airflow setback is one of the more significant opportunities for energy savings in unoccupied ORs, and is included in the American Society of Healthcare Engineers (ASHE) white paper [PDF] on OR HVAC setback strategies. ASHE’s “Operating Room HVAC Setback Strategies” provides guidance that warrants consideration by facility engineers. In this post, I would like to highlight and qualify some of the important insights from ASHE regarding OR HVAC setback strategies.

Commercial buildings have complex systems, end uses, and operations making managing their energy use a challenge. “Big data” is the trend in the building energy industry, but operators do not have time to analyze operating data. We need to provide building operators with easily digestible information including:

It’s that time of year again – summer – season of vacations, sunscreen (for me at least), mowing the lawn and (queue ominous music) the dreaded “Battle of the Office Thermostat.” We all know what this is. You go to work in an office and, if you’re a woman, when the man sitting next to you is perfectly comfortable you are teeth-chattering freezing. If you’re a man and the woman next to you is comfortable, you feel hot and stuffy. Disclaimer – I am a man. Second disclaimer – I don’t wear skirts and sandals to work, even if it’s 90 degrees outside.

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.

Engineers and energy managers use many different types of instruments to help identify energy efficiency opportunities in an existing facility. Loggers that have been discussed in previous blog posts are a good way to assess how building equipment performs over time, but I am going to talk about some measurement tools for energy audits and RCx (retrocommissioning) that can be used to instantaneously identify potential issues that can lead to higher than needed energy use.