Enhancing the learning experience in K-12 schools: Automation and controls
K-12 schools are among the most important projects engineers can tackle. Automation and controls help keep these educational facilities running smoothly.
Tony Cocea, PE, Principal, DLR Group, Los Angeles
Michael Do, CEM, CxA, AX TCP, Director of Engineering Sciences and Commissioning, Setty, Fairfax, Va.
James Dolan, PE, CEM, CPMP, LEED AP, Principal in Charge of Energy Engineering Services, OLA Consulting Engineers, Hawthorne, N.Y.
Mark Fisher, PE, LEED AP, Principal, AlfaTech Consulting Engineers, San Jose, Calif.
Douglas R. Hundley Jr., PE, CGD, LEED AP, CxA, Mechanical Engineer, CMTA Consulting Engineers, Louisville, Ky.
Peter McClive, PE, LEED AP, Senior Vice President, CannonDesign, Grand Island, N.Y.
CSE: When working on monitoring and control systems in K-12 structures, what factors do you consider?
Do: When designing controls systems for K-12 structures, it is important to consider occupant comfort first and foremost. Our ultimate customers are the kids that are there to learn, and we need to be conscious of providing sequences and systems that will offer an environment that is conducive to that.
The majority of our clients in this sector have multiple facilities and are looking to standardize the look and feel of the controls across their portfolio. Our designs incorporate open platforms to try to meet this desire for consistency without sacrificing the clients' ability to seek completion from the free and fair marketplace. While the push for open protocols, such as BACnet and Modbus, have helped foster competition, it has not solved the problem of each vendor using exclusive tools for their controllers that prevent competitors from being able to edit or service them. Open-platform products, such as those built on the Tridium Niagara platform, give all suppliers access to identical programming tools and allow owners the ability to competitively bid service projects and retrofits without having to worry about dealing with multiple vendors for any various controls in their facilities.
Cocea: The main factors we consider are: the control system's level of user-friendliness, whether the control system has tech support, and how can we take a proactive approach to the project.
Fisher: Districts typically like direct digital controls (DDC), but maintenance people are not familiar with how to maintain them, so we always keep ease of use for all users in mind for a project.
Hundley: Owners' requirements vary, depending on whether it is a net zero building or a high-performance building. Some owners like to see different components of energy usage, which requires submetering. Outside of the specialty items, we consider all sensors or information needed to properly monitor the system and allow for remote diagnosis of a system. That is the real value to school-district maintenance staff. If they can partially diagnose the problem before going to the school, they will be able to reduce the amount of time spent on maintenance—and the resulting downtime—potentially affecting the classroom space conditions.
Dolan: Energy efficiency goes hand-in-hand with comfort control for students/teachers as well as maintenance of systems. Individual control of classrooms is imperative and can span from HVAC controls and lighting to operable windows. A classroom may be thought of as a "black box" space because it is often unknown exactly how that classroom will be used from day to day and year to year. A building management system (BMS) that trends the important parameters will enable operators to ensure the key features are available and operating properly and in an efficient way. When specifying energy meters, the interoperability with the BMS being used is a key factor to ensure they work as intended.
CSE: What types of cutting-edge sensors, biometrics, or other controls are you specifying in K-12 projects?
Hundley: The main thing we have been using is submetering systems to monitor different components of energy, whether it is lighting, HVAC, or even different grade levels. This helps to identify systems that might not be working correctly or that can be operated more efficiently. We also have been using different systems to allow for demand-control ventilation, which has resulted in significant energy savings and achieving cost-effective net zero schools.
Fisher: Card readers and video-surveillance cameras are becoming more prevalent as more districts are recognizing the importance of increased security and monitoring on campus.
Cocea: We are consistently looking at dual-type occupancy sensors, carbon dioxide sensors, and touchscreen technology in K-12 projects.
CSE: What are some common problems you encounter with building automation systems (BAS) in such projects?
Dolan: Often, the controls are brought online very late in the construction process and at times are completed after occupants are in the building. Getting changes that are desired when it is late in the process can be difficult. BMS/BAS systems are more flexible and ubiquitous than ever. Specifying the sequence of operations should occur earlier in the design process to help ensure the operation of the HVAC system is as intended and maximize the flexibility of the systems. By making the intended system operation clear to the end users earlier in the process, the integration of the controls with the equipment to be controlled can be coordinated, and any questions on operation can be vetted with the owner, which would help manage expectations.
Do: Lack of coordination between the mechanical and controls contractors with regard to controls integration is a major problem we encounter. More pieces of equipment are coming with onboard controls, and precise plans and specifications are needed to avoid scope gaps with regard to provision of controls instrumentation and performing all aspects of the sequence of operation. Simply specifying BACnet protocol is not enough to ensure cohesive interoperability between systems.
On the commissioning side, we recently encountered a project where the air handling units specified use of packaged controls that were not capable of any static pressure reset control—although the sequence called for the units to do so. This created a conflict with regard to meeting the intended design.
Hundley: One problem is getting remote access, allowing us to collect data to improve designs. We understand the schools have to protect their networks, but some type of remote access would be helpful to engineers for collecting data and improving design. We collect data through the owners, but it limits how much data can be collected.
Fisher: Scheduling enough time for commissioning, programming, and training the owner for maintenance procedures. To address these problems, we find that the simpler the system is, the better.
CSE: What types of system integration and/or interoperability issues have you overcome, and how did you do so?
Dolan: A key challenge for system integration and interoperability occurs with energy metering. If meters to monitor usage are installed by individual trades and then the information is pulled back into the BMS, the integration of the meters can be a challenge. One solution is to have the controls contractor purchase the meters and have each respective trade install. This could reduce the interoperability issues and result in a single point of responsibility.
Hundley: Small or large districts all face a similar problem. On one hand, you would like to standardize controls, but you have to be careful to allow for competitive bidding to keep costs reasonable. Plus, a lot of state institutions require you to include multiple manufacturers for competitive bidding. Most of our districts have a standardized graphic software and system structure that allows multiple manufacturers to provide services.
Do: Lack of coordination between the mechanical and controls contractors with regard to controls integration is at the root of the majority of problems we encounter. In our specifications, we require the contractor to name a master controls integrator who is ultimately responsible for ensuring that the systems installed will be able to meet the full design intent. This starts with a controls coordination meeting that takes place during the submittal phase of a project to work through any potential scope gaps early in the process. The master controls integrator can be one of the contractors on the project, a neutral third party, or sometimes we fulfill this role for our own designs. When designing integrated controls, our engineers will use the manufacturers' point register to determine exactly which data points are available for sharing across the BAS for the basis of design units and provide this information on the drawings.
CSE: What unique tools are K-12 school owners including in their automation and controls systems?
Hundley: Primarily, the tools are properly placed sensors, allowing proper diagnosing of the building systems.
CSE: How do you meter or submeter the various portions of the building, such as a gym, auditorium, cafeteria, etc.?
Cocea: There are two ways to meter power. The typical method is to segregate the loads to different panels, and each panel can be metered at the main feeder. This is applicable to larger loads that will require you to provide several panels. For smaller buildings where it is not cost-effective to provide full-scale panels, there are two options: one is with a split-bus panel and the other is a panel with branch-circuit power monitoring. A split-bus panel has two sections, and the upper section can be metered separately from the bottom section. The upper meter shall register the totalized panel load and the bottom meter shall register the bottom half-section load. Subtracting the bottom meter load from the upper meter load gives you the upper section load. A panel with branch-circuit power monitoring is a regular panel and has two strips of current transformers (CT) located inside of the enclosure. A 42-circuit panel can have 42 CTs to monitor every circuit load.
Do: Most of our K-12 clients are interested in facilitywide metering more than individual space resolution. However, one recent net zero-ready project was designed to provide measurement and verification at the sample rate and granularity required by LEED measurement and verification (M&V; real measurement, not modeled, and not from utility bills), and to provide for current and future energy mandates. Additionally, the metering points were incorporated to augment controls resets and optimize energy savings through advanced sequence of operations and the mandatory post-construction tuning processes executed by the master controls integrator. Individual current transducers and power-monitoring hubs on each piece of equipment were integrated to the BAS, and using temperature- and flow-monitoring devices for both air and hydronic systems allowed for comprehensive tracking of Btus. The lighting system was also fully integrated at the classroom level of resolution to pinpoint total energy consumption throughout the facility. Generally, this level of metering would be too costly for most customers, but for facilities looking to pursue net zero, it can be beneficial.
Fisher: We are not seeing metering and submetering in K-12 projects, but we are seeing it in higher education projects where campuses are larger and more diverse.
Hundley: We are typically more interested in the energy usage of various systems (HVAC, lighting, information technology, etc.) instead of different areas of the building. We have in the past metered the first-grade wing versus the second-grade wing, for example, to foster competition. Multipoint meters make it possible to monitor all building loads from a single location. This allows us to install one meter (with multiple sets of CTs) at the main switchgear, instead of large quantities of individual meters throughout the building, to capture all loads.