Building Energy Resilience

June 2022 update: Given the current supply chain and labor shortages the construction industry is facing in 2022, looking after your building's existing systems becomes even more important. With equipment delivery for major systems sometimes many months away, retrocommissioning your existing systems can help tune them up to keep them in tip-top shape to get more usable -- and efficient -- life out of them. 

When people ask me what I do for work, I generally tell them I’m a building systems engineer, with a big focus on making facilities more energy efficient and comfortable for occupants. One common part of my job entails going to a building to perform an energy audit or assessment. During these visits, we follow the same straightforward outline:

1. Walk through the site
2. Inventory all energy-related equipment including lighting, mechanical systems, building envelope, etc.
3. Speak with the building operator about how they run the building
4. Ask the building owner, occupants, and operator about and any issues or concerns they have regarding maintenance, equipment that is not working properly, or comfort problems.

Through these visits, we produce a report that documents not only the existing building systems, but recommendations on equipment upgrades or operational changes that can be made to save energy or improve comfort. We also provide quantification of energy and cost savings for each identified opportunity so that the building owner knows how much of a bang they get for their buck.

In this time of global crisis, it can be hard to cope with some of the new realities we’re all being faced with, whether it’s experiencing isolation due to social distancing, fearing for yourself or loved ones, or dealing with the virus’ economic impact. As a business that strives to engineer a future where buildings are better for people and planet, we can’t help but notice the ways this crisis reflects global warming’s looming themes: it’s going to affect everyone, it has dangerous consequences, and it takes a global effort to combat. While I only have the emotional bandwidth for one global emergency at a time, the environment is still in the back of my mind, and I can’t help but think of the ways the virus and our environment are inextricably linked.

After an early morning departure and a snowy drive, my colleague and I arrived onsite to test, among other equipment, a packaged rooftop air handling unit with factory controls. At first, the unit appeared to check all our boxes, but as we dug into the details, it became clear that this would be a very expensive heating system to operate. This blog entry is about factory controls and the importance of getting into the weeds to identify issues like the one we found with this rooftop air handling unit.

Similar to other domains, data from buildings is being generated at an unprecedented pace and scale. However, all of that data is useless if we can’t extract meaning to create value and yield actionable insights. This requires the utilization of protocols or standards to effectively make sense of the data. Project Haystack is one such standard that has been developed over the past several years and allows for the contextual tagging of data in a flexible way, using data from any number of sources.

Thanks for following the second part of the ground coupled heat pump design. If you haven’t already, now’s a good time to go back and read Part 1. In the first part of this post, we discussed the importance of understanding thermal imbalance in a ground source heat pump system and the longevity impacts associated with an imbalanced system. Despite the issues associated with a thermally imbalanced system, there are ways to address building loads with additional technology that will further enhance the performance of the ground-coupled heat pump system, as well as provide long term performance.

The ground source heat pump is a wonderful technology that will be vital in achieving energy efficiency goals this century. This technology isn’t new, but it is beginning to become more accepted as a viable solution for large scale, high efficiency HVAC performance. There are two main types of ground source heat pump systems: those that are “Ground Water” (also called Open Loop) and those that are “Ground-Coupled” (also called Closed Loop), see Figure 1 below. In either case, the water from the ground is pumped to a heat pump, where heat is either extracted out of or rejected into the ground and moved into or out of the conditioned space.

As you know, Cx Associates’ work focuses on making buildings perform better for occupants, operators, owners, and for the planet. A common metric we use to assess building performance is the energy use intensity (EUI) which Katie has discussed in her recent blog posts. While attending the recent IEPEC Conference in Denver, I had a discussion with someone familiar with Xcel Energy’s work to be a net zero carbon utility in the relatively near future. We realized that EUI is an insufficient metric for guiding energy program investments at their customer sites. Ultimately, to drive carbon emissions down to a sustainable level that will halt and begin to reverse the climate crisis we are currently in, we need to track energy intensity while also focusing on carbon emissions intensity (CEI) at a building level. Cities and states that have adopted carbon reduction goals will do well to focus on reducing the CEI of their building stock through energy efficiency, fuel switching, and renewable energy generation.

In a previous blog post, I discussed the energy benchmarking service we currently perform for a healthcare network using the Energy Star Portfolio Manager (ESPM) tool. This tool is used to monitor the energy usage of a building over time. It allows a user to set energy goals, compare the overall energy use intensity (EUI) to a baseline year, and compare the building in question to other buildings with similar use-types and characteristics. In addition to continuing this specific service for the healthcare network, Cx Associates uses the benefits of benchmarking in other areas of our work too. This blog post will discuss what other areas of our work utilize benchmarking and then provide a brief update on changes ESPM has made to their scoring metrics over the past year.

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: Planning, Investigation, and Implementation.

As the newest engineer to join the Cx Associates team, I have had the immense pleasure to be able to approach buildings from a different angle than in my previous work experience. In my former work as a mechanical design engineer, the focus was on current building technologies and keeping up with the most cutting-edge designs for our systems and buildings. Don’t get me wrong, looking to the future of efficient building technologies is tremendously important, but as someone who is concerned about the current state of the environment and ensuring there’s a habitable world for generations of living things to come, I found it hard to believe that new buildings alone are capable of being more than a small drop in a big bucket. After all, there are only a small number of new buildings built each year compared to the vast existing building stock. A quick look at the numbers from the Commercial Buildings Energy Consumption Survey (CBECS) by the US Energy Information Administration (EIA) will tell you that of the total data set, only about 18% of commercial buildings were built in the most recent 12 years surveyed. (https://www.eia.gov/consumption/commercial/data/2012/bc/cfm/b8.php)