Babel Buster: It is how to connect things to BACnet.
Smart Buildings & Smart Energy:
In July, twenty of us gathered in DC for a two-day charrette on the standards needed to apply BIM to the problems of dynamic energy management. The work-shop, entitled “Smart Buildings, Smart Energy”, was put on by the Corps of Engineers Research Lab (CERL) at the National Institute for Building Science (NIBS). The meeting was a fascinating, and occasionally heated conversation that brought together academic and government researchers, building system practitioners from industry leading companies, and participants in standards committees from ASHRAE to OASIS. It was a fascinating meeting, filled with bright, deeply focused individuals who as a group had not yet recognized the profound changes in their goals required for smart energy.
The challenge of smart energy to buildings is dynamic
change. The goal of smart buildings has always been superior performance—usually
defined as energy efficiency. Energy from external sources will all become
dynamic and intermittent. Some will be available under rapidly changing prices.
The most efficient system may not be the one that is most able to respond to
these changing conditions. Perhaps the goal of smart buildings is to defend its
occupants from the degraded conditions of the smart grid. The game is changing.
The use of Building Information Models (BIM) is only now becoming common enough to change business processes. BIM lets us design buildings the way we design cars and planes, with full simulation and testing before the contractor turns over the first shovel full of dirt. BIM furthermore provides the contractor with accurate materials requirements and each trade with accurate measurements. With better knowledge and a dramatic reduction in re-work, the cost of construction can come way down while the quality goes up.
Most of the cost of a building is incurred in operations, during the long period between construction and demolition. For the last five years, led by NASA and CERL, there has been a project to define how to hand over information from design and construction for use in operations. The Construction Operations Building Information Exchange (COBIE) defines how to hand over information from the BIM to maintenance and operations.
The information in COBIE seems almost trivial—unless you don’t have it. COBIE defines a standard exchange for equipment information including spare parts lists and preventive maintenance schedules. COBIE exchanges are defined as a series of simple spreadsheets, which can be generated from BIM or filled in by hand. A growing number of maintenance management systems are now able to import COBIE directly into their databases. Whether or not a building was built using BIM, whether a building is old or new, the owner can request COBIE formatted information for handover from the builder, commissioning agent, or seller.
Francois Grobler gathered us together to discuss how to extend COBIE to reduce the cost of building system integration. Building systems are classically islands of automation, communicating only with a single proprietary console. The cost and time required for integration is a barrier both to better integration, and to system upgrades. Occult system tags and poor documentation prevent the timely value-based upgrades that drive innovation in the IT world.
This last point is critical if we are ever to get to a highly innovative green-tech. Cost-based upgrades look to historical cost and to growing maintenance problems to decide when to upgrade. Systems are not replaced until they fail or have been completely depreciated. As IT merged with telecommunications, we moved to value-based upgrades. Lap-tops and PDAs are upgraded when they give the sales force a competitive edge. Work-stations are upgraded to increase engineering productivity. This dynamic has driven these worlds to innovate to drive shorter sales and replacement cycles. The difference is the one between the old black hand-set we used to lease from the phone company, often for decades, and the new market of cell-phones and the latest functions.
A key component of this new COBIE will be control system tags and metadata. Today, a retro-commissioning agent spends the first days or even on site in low-value discovery of this information from blue prints and the current control system. Only after this work is complete, can the more high-value and useful work begin. When a project such as this is completed, those working notes are thrown away, or stored where they see no further use. A standard for the exchange of this information would reduce the costs of each commissioning and perhaps stimulate a market for third party discovery tools.
Space is the most important class of metadata. People in buildings inhabit and interact with spaces. Building systems affect those spaces, and secure those spaces, but the relation between systems and space is often occult. BIM can provide the mapping, but we don’t need all the BIM for that. We need something small and lightweight, that describes the three dimensional space, but leaves out the details that add complexity.
The most significant use of BIM will be in buildings that built without using BIM. Most buildings next year are not new; most new buildings next year will be built without using BIM. Even if we were to imagine that in five years, all buildings will be built using BIM, most buildings still would not have a full BIM, with an intelligent structure, for a very long time. Fortunately, we do not need a full BIM to describe the space in buildings, and to provide a light framework integrating system information with that space.
Retro-BIM is the work for taking one of today’s buildings and creating a BIM for a portion, usually during a renovation. These BIMs tend to be descriptive, and lack the full engineering detail that would come with design through BIM. There is a growing set of tools and practices to cost effectively create a three-dimensional BIM during a renovation. Retro-BIM can provide as good a foundation for a light integration framework as can a full design BIM.
Green Building XML (GBXML) was designed to provide a “good enough” description of building space and building systems to support energy models that are “good enough”. GBXML is based on the IFC data models that underlie design BIM. Because GBXML already includes information on space and systems in a light-weight model, GBXML would need only a little extension to map system tags and related system metadata to space. Retro-BIM datasets, designed to map to the IFCs, should be able to expose information as GBXML with little trouble.
The new challenge of smart energy is dynamic decision-making. Volatile energy availability and energy prices will make the grid an unpredictable supplier. The availability of on-site energy sources, both generation and storage, enable self-reliance. Smart energy will require energy use decisions on a minute by minute basis. Buildings must be able to accept the complexity of new systems and new technologies without bearing the additional cost of complex integrations. GBXML might be the shim between systems, space, and the people that occupy that space that lets us put it all together.
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