Thought Leadership
January 6, 2023
Written by Consulting-Specifying Engineer
To appeal to various clients and work styles, office buildings are moving toward becoming more energy efficient
Office building insights:
Participants:
Pictured left to right: Miles Brugh, Adrian Gray, Matt Humphries, John Yoon
Describe a project in which electric vehicle charging stations were included. What were the challenges and solutions on this project?
Miles Brugh: Electric vehicle charging has come on like a storm in the industry. Specifically in the city of Chicago, officials have passed an ordinance that requires all new commercial projects to provide capacity for 20% of all parking spots to be EV-ready. Our designs factors in this additional capacity. We have also been seeing an increase of Day One installed from two to four chargers, currently growing to up to 10% of the total parking spots.
Adrian Gray: We have delivered charging stations across the U.S. and also around the globe. EV charging presents an operational challenge in that the demand schedules tend to be unknown in that they can vary from hour-to-hour. When combined with client-specific utility electric rate schedules that offer time-of-use incentives or demand-based charging, this EV charging inconsistency can sometimes do more financial harm than good with these specific types of utility structures. The solution is to work with the electric utility company to allocate the EV charging to a separate building meter with its own rate structure and keep the building loads on the rate structures that can benefit from demand-reduction based measures.
John Yoon: We are often asked to perform feasibility studies or integrate level 2 EV service equipment (EVSE) into our projects. While it isn’t much of a challenge to have a small number of them, we’re seeing requests to accommodate dramatically increased EVSE quantities.
For example, Chicago has a parking zoning ordinance for new construction that mandates that associated parking areas be EVSE-ready. In general, anywhere from 1.33 to 2 parking spaces per 1,000 square feet of building area are required overall for business occupancies. Chicago’s ordinance requires 20% of that total quantity of spaces be EVSE-ready. Assuming 6.6 kW per EVSE, the power required by those EVSE is starting to approach what we reserve for lighting and receptacle usages in the office areas. While we can accommodate that in new construction, that is seldom the case in existing buildings. When those buildings were originally constructed, no one had any indication that this type of electrical load would need to be accommodated.
The preliminary drafts of the 2024 IECC would seem to indicate that there is a good chance that EVSE requirements will be incorporated into that code. This is a game changer and will dramatically change how we design electrical distribution systems. Load management systems to allow multiple chargers to share a limited source of power seems like the obvious solution to capacity issues.
However, the American EV market is moving faster than codes and standards development. Without universally mandated standards, vendors have little motivation for standardization and as a result, most available load management solutions are proprietary. However, this might change with requirements associated with EV charger infrastructure funds that were earmarked in federal government’s Inflation Reduction Act.
What unusual systems or features are owners requesting to make their office facilities more efficient?
Adrian Gray: Not necessarily an unusual system or feature, but more and more we are seeing building owners want more granular validation that their building operation is efficient and performing as per the design intent. At HDR we find that this is most successfully achieved via a cloud-based or locally hosted fault detection and diagnostics (FDD) platform that collects interval data from the building automation system to seek out energy-related anomalies that impact building performance. FDD identifies sensors that have deteriorated or are drifting, sequence of operations that are not operating as intended, irregular equipment efficiencies and occupancy-based optimization recommendations.
Matt Humphries: There’s a focus on carbon. There’s a real appreciation for looking at the long-term operational carbon and energy use in buildings. What is the carbon cost of construction? How much embodied carbon is there in the building at the outset, not including future ongoing energy use? Arup is at the forefront of appreciating the life cycle carbon impact of construction. A key developing trend is to look at the carbon content of mechanical systems, in terms of both embodied and operational carbon.
John Yoon: Again, upcoming building performance standards and decarbonization efforts are an overriding concern. Specify thresholds for building energy use intensity will naturally force us into more efficient systems and equipment selection. It isn’t going to be an owner’s request — it will be a requirement.