Getting it right in mixed-use buildings: Automation and controls
Mixed-use buildings—often a combination of retail and residential—are unique structures with varying needs. Automation, controls, and system integration are big components of these mixed-use buildings.
Michael Albanese, PE, LEED GA, Senior Associate, Kohrs Lonnemann Heil Engineers, Fort Thomas, Ky.
David Callan, PE, CEM, HBDP, LEED AP, QCxP, Vice President, McGuire Engineers, Chicago
Donna Miller, PE, PEng, LEED AP, Vice President, Engineering, WD Partners, Dublin, Ohio
Gary Poole, PE, Principal, Bury Inc., Houston
Andrew H. Smith, PE, CEM, LEED AP, Principal, Jordan & Skala Engineers, Dallas
CSE: When working on monitoring and control systems in mixed-use buildings, what factors do you consider?
David Callan: Mixed-use buildings often have multiple systems types, operators, and financial stakeholders. This can lead to multiple automation systems controlling various equipment and systems associated with their specific ownership or lease. This can run the gamut from fully integrated networks to completely separate parallel systems. The age of the building and available funding for upgrades will dictate many of those decisions.
Smith: The type of controls will vary depending on which mixed-use building types are married together. If multifamily or hospitality is one of the components, it is key to pressurize the corridors and minimize humidity levels. In addition, ducted fresh air (ventilation) needs to be controlled to deliver the amounts required by code.
Poole: Beyond the basic climate issues for the location of the project, the key is to understand how the facilities will be used. The monitoring and control systems should be designed to address differences between facilities in terms of size, people who use it, design, etc.
Miller: We consider the end users' requirements and their needs for active control of comfort conditions, zoning demands, and interoperability issues that may be present between terminal equipment and central plant equipment. We also work closely with the end user to define the requirements for open systems or for proprietary control systems.
CSE: What types of cutting-edge sensors, biometrics, or other controls are you specifying in mixed-use buildings?
Poole: Control components seem to reach obsolescence within 2 yr of common application, so the new systems will usually have components that are of greater accuracy and reliability. Concealed-type devices are gaining in popularity, but there is always a budget concern with these devices.
Callan: In truth, we aren't seeing much interest in the James Bond 007-style of gadgets that we see heavily marketed. There appears to be more interest in those technologies internationally. Domestically, emphasis seems to be placed on security, access, and elevators. On the BAS side, we see a trend toward improving the reliability, "openness" of the system, and better "nuts and bolts."
CSE: What types of metering, submetering, or other systems have you specified for a mixed-use building?
Poole: The metering or submetering is normally used to identify usage of a service by entity or function. We have frequently used metering and submetering for power, water, cooling, and heating services if permitted by the local code and utility provider.
Miller: We have specified electrical panels for submetering-system power consumption to gather data for overall demand from HVAC plant, lighting, and process/nonregulated electric power loads. We have also specified similar submetering for gas systems used in food service applications within larger mixed-use buildings.
Callan: When multiple HVAC systems share the same central plant(s), there is a need for submetering. Traditionally, thermal energy (Btu) meters have been notoriously inaccurate. The technology is continually evolving, and becoming more reliable. But the management of submetering remains an issue. Regardless of the sophistication of the automation system, the billing is still done by accountants and verified by business professionals and attorneys. They tend to be less impressed with our magic black box algorithms. So, building managers often take our sophisticated calculations and simplify them to something you can write on a napkin. Engineers must remember that we are ultimately solving people problems and not machine problems. Precision, accuracy, and practicality don't always align.
Albanese: The diverse functionality of a mixed-use building provides many situations that require specific metering needs. Often, the engineered systems will dictate the metering types that are used. It is necessary to consider the lifecycle of the building when considering the metering requirements of a mixed-use building. Designs that accommodate apartments initially have to consider the potential that they could be converted to condominiums in the future. This consideration may require the engineering team to design independent metering systems in lieu of specifying tab meters and submeters. The application of variable refrigerant designs continues to grow. As such, algorithmic power-consumption programs are being specified to allow for tenant submetering on interconnected systems. Consistently, the application of Btu flowmeters, airflow meters, and utility tab meters are used in mixed-use buildings depending on the requirements of the owner.
CSE: What are some common problems you encounter with building automation systems (BAS) in mixed-use buildings?
Miller: Some of the challenges we encounter with BAS is the interoperability of controls between BAS and packaged unitary controllers. Additional challenges occur with accurate/repeatable outside airflow monitoring and control when using equipment manufacturers' tracking dampers.
Poole: Mixed-use facilities add an extra dimension of complexity for most automation systems due to the varied nature of the space usages. It is very important to spend time with the control vendor to ensure that there is a high level of understanding of the project goals. After the installation and commissioning of the system, the most common problem with BAS in mixed-use facilities is the unintended consequence that can be associated with making a schedule change to any of the systems. The nature of a mixed-use facility is such that there will frequently be a need to modify set schedules for parts of the facility. Many times, the effect of the change is not completely understood prior to the change.
Albanese: Specifying a BAS can have consequences in the future with servicing and maintaining the system. Consequently, we specify open protocol systems that do not establish a permanent brand or manufacturer for the life of the building. These systems may come at an increase in first cost, but provide flexibility moving forward. Additional problems are created if the complexity of the system is above the capabilities of the owner or facilities personnel. Providing an automated system may not be needed if the needs of the owner and a stand-alone system will suffice.
Callan: The problems we encounter are often not the products of technological limitations. They are problems resulting from the constraints imposed by people. Lines of ownership, multiple operators' approaches, preferred vendor relationships, and the like can dictate inefficiencies.
CSE: What types of system integration and/or interoperability issues have you overcome, and how did you do so?
Miller: Most of our challenges have been solved by the addition of translators. Other issues have been overcome by adding outputs to the controls to directly monitor the performance of the system within the ducts or the piping.
Callan: In an ideal world, we will be working with the same open protocol across a mixed-use building, regardless of the operator. In this case, most integration problems can be rectified with programming. Otherwise, multiple gateways and programs must be coordinated for every data-exchange conduit.
CSE: In your mixed-use projects, have you worked to incorporate the Internet of Things (IoT), the Industrial Internet of Things (IIoT), or Industry 4.0? Are other countries more, less, or equally advanced when compared to U.S. projects?
Callan: Domestically, IIoT is in its infancy. There are many applications and use cases for large energy-consuming systems and equipment that make IIoT attractive. Most of these require third-party, cloud-based services because owners don't have the expertise and resources to benefit from most of the IIoT technology independently. Most of the people responsible for implementing this sophisticated technology, at a building level, are just like you and me—and are flummoxed when they can't get their iPad to sync with iTunes. Personally, I struggle with the idea that someone sitting in a data center 2,000 miles away can diagnose a system and understand the holistic complexities (human and machine) that might lead to a component failure without ever touching it or talking to anyone. There simply isn't enough consumer money in fault detection and diagnostics yet to support its perfection. The same cannot be said for cell phones, which allow the user to simulate slicing various fruit and melons with samurai swords.