Building Energy Resilience

Retrocommissioning (RCx) or Existing Building Commissioning refer to a technical process that retrofits and tunes building HVAC control systems so that buildings function more efficiently and effectively.  The RCx process has historically included three primary phases:

During the Kyoto Protocol meetings, the world thought governments were going to lead the carbon-emission reduction efforts. But the foremost carbon-emitting countries (US included) didn’t sign this protocol and, until recently, seemed content with sidestepping any commitments.  Now 25 years later, the world itself is calling for change, and governments are finding grassroots support from the public as they go into the Paris Climate Change discussions.  Companies world-wide are initiating energy and waste reducing measures and promoting renewable energy procurement themselves, without mandates, because they see the economic benefits.  The tide has turned.

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.

In the five years or so between the late 2000s and 2014, prices for large-scale solar photovoltaic (aka “solar PV” or “PV”) power generation installations have fallen by 50% due to reasons including incremental technology improvements, higher production volumes, more efficient manufacturing, and more efficient and competitive installation. The news of falling large scale solar PV costs is not new to those who follow these kinds of things, but the continued drastic decline in prices has brought us to a point worth noting. A recently released Lawrence Berkeley National Laboratory (LBNL) report on this subject titled Utility-Scale Solar 2014[1], found that the 20^th percentile of utility scale PV project costs (the least-expensive 20%) were installed for around $2 per Watt_AC. Some notable recent utility-scale PV power purchase agreements (a.k.a “PPAs”, which are contracts between producers and buyers of power typically for a fixed price per megawatt) in the Southwestern US have been for prices as low as $40/MWh—the study notes that at this price, solar PV is competitive with the fuel-only component of operating a natural gas plant (i.e., ignoring gas generation fixed capital costs such as the power plant itself!).

Last night I got to spend time with two of my closest friends. We were showing off the well-insulated basement of our new home, and my friend relayed the story of his contrasting clients. For one client he is upgrading the basement and planned to use closed cell spray foam as the insulation material. The client became concerned about off-gassing just before the application and put the project on hold. A different client (an elderly couple) is selling their home and moving into a new trailer. Tom went to install the baseboard trim for them as a favor. When he arrived on site he found the new trailer to be virtually uninhabitable for him and his crew without the windows open. On the kitchen counter he found this label:

Is the energy efficiency field growing up? I am cautiously optimistic that the answer to this question is “yes.” From the discussions of the major carbon producers - China and USA – regarding limits to their emissions, to building codes ever increasing minimum building efficiencies, and efficient technologies being accepted by the market, it seems promising. Another positive sign is that energy efficiency programs are starting to go deeper into more complicated measures. This means we’re moving energy efficiency programs past the “low-hanging fruit” that the market understands, and administrators are looking towards new areas and technologies.

Technology and innovation have brought us great advances in energy efficiency. As examples, just look at the shift from incandescent lights to fluorescent lights and now to LEDs, or the move to variable air volume (VAV) air distribution systems from constant volume during the energy crisis of the 1970s. Those two evolutions alone have probably saved yotawatt[1] hours of electricity since they were introduced. The trend continues today with things like advanced building lighting controls and energy recovery air handlers.

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.