Innovations in Comfort, Efficiency, and Safety Solutions.
Thomas Hartman, P E
Despite the building industry’s efforts to place a greater emphasis on improving energy efficiency of buildings, the dreadfully slow pace of improvement is resulting in an ever widening gap between what is attainable and what is actually being attained. The building design community could soon lose its leadership position on the issue and quite correctly be seen more as part of the problem in lackluster building performance instead of the solution it strives to be. I fear the industry could soon be overrun by a public clamoring for higher performing buildings; this industry’s businesses and institutions run the risk of being displaced by others offering better solutions.
Hardly a day goes by that I don’t have a discussion with a fellow engineer who believes as I do that designing and constructing building energy systems using half or less the energy of the most efficient of today’s buildings is a simple matter and well within current building project budgets. We agree the problem is not some mysterious outside force that is holding us back. Rather, the problem is rooted right here in this industry; it is the very nature of the way the building industry works that must change to leverage new more energy efficient technologies effectively into our industry.
I and others have been calling this needed change a switch to “Performance Based” Building Design and Operations. This new approach is focused on revamping the “process” of designing, constructing, and operating buildings. It is only through such new processes that promote a greater focus on energy efficiency and sustainable buildings along with enabling greater support for new and more efficient building energy technologies that the building technology and performance gap can be narrowed.
In performance based building design and operations, the role of the design engineer is dramatically changed from the way design work is now generally performed. This new approach to building design calls for the project engineer at the start of the project to work with the Owner and architect to develop specific performance criteria for the building project. And one important performance criteria is the energy performance of the building. That may not be too different from today’s typical early stage design activities. But then, once each element of performance criteria has been developed and defined, the project engineer’s primary focus throughout design, construction and turnover is to work to ensure all the performance elements for the project are achieved and are certain to be maintained over time in actual building operations.
This new role contrasts considerably with the current common design philosophy of carefully detailing every element of a design so that the contractors do not compromise the design intent. There are two important reasons this approach is outdated and rarely succeeds in achieving the level of performance newer technologies permit. First among them is the problem that the newer technologies are beyond the grasp of the general engineering consultants that design the energy systems for buildings today. The relatively simple design approaches and equipment configurations that were employed years ago are now outdated and cannot achieve the performance new technologies and configurations offer. But design engineers have not and cannot be expected to keep current with all the aspects of the new technologies becoming available to the industry. The result is that most designs today are out of date; they focus almost entirely on improving the efficiency of components, the building envelope, the heating, cooling and lighting systems, all without considering the needed new configurations and the optimized integration among these systems new technologies afford. It is certainly not uncommon to hear contractors and equipment manufacturers express concern that they are being limited in the newer technologies they can apply to or in their systems and equipment by the outdated requirements designers incorporate into the project specifications. Therefore, in many designs the failures in achieving attainable energy performance can be attributed at least in part, to the engineering design process itself.
The second important reason the current method of building energy system design cannot succeed in delivering energy efficiency is the lack of accountability for the energy performance of the building energy systems. Because it is the engineer that executes the detailed design, it seems to some that the engineer should be the point of accountability for performance. But engineers have only limited influence over many of the decisions that are made after the design is turned over to the contractor and almost no influence over how the system is operated once it is turned over to the owner. For these and other reasons, engineers correctly resist accepting any accountability for ensuring building energy systems actually perform as projected. But if the designer of these systems cannot be held accountable for their performance, who should be? Here too, failure to achieve high levels of performance can be attributed directly to limitations in the design process.
The solution to these design process failures is not to blame the engineering profession which for the most part is doing the best it can, but to initiate the development and implementation of a new approach to building energy system design that recognizes and overcomes the shortcomings of current practice. Performance Based Building Design and Operations is an attempt to develop the framework for such a new approach. Below is a very brief outline of this developing energy system design strategy and how it is being constructed so that it can overcome the two hurdles to success listed above.
The first problem noted above is that of properly incorporating new, more effective and efficient energy system technologies into building energy system designs. To do this, engineers need to step back from the detailed component and configuration designs that are common practice today and develop designs that are specifically performance oriented. Detailed specifications are still required. But what is specified is quite different so that the implementing subcontractor has both the flexibility and the responsibility to achieve the performance criteria embedded in the specifications. This is a substantial variation from current practice wherein subcontractors typically have very little flexibility but are often expected to take responsibility for performance of systems they have not designed. As the contracting industry has become more sophisticated giving it flexibility is a natural fit into the expanded capabilities that now exist within the contracting community to design and construct their systems for buildings. Many subcontractors have design engineers on staff and have an ability to work directly with the equipment manufacturers and others in the contracting team to develop specific system configurations and operating parameters that a project engineer cannot hope to achieve in part because the contracting and product selection has not yet been made at the design stage.
Once a change to performance oriented design is developed, the problem of accountability is also easily resolved. The project design engineer’s responsibility is to provide oversight of the construction, commissioning, and turnover processes so that the responsible contractors are held accountable for the performance levels each has been contracted to provide. In this effort, I liken the project engineer to the conductor of an orchestra. The conductor does not compose or play the music, but he or she does manage the process so that the audience is assured the expected level of performance is realized. To accomplish this type of management in a building project and achieve success with performance based design and operations, engineers should consider the advice of the famous conductor Andre Previn. He laments that to become a conductor he had to give up music! Project engineers need to consider that tongue-in-cheek remark to reinvent the way they do their job in order to more effectively manage high performance building projects. Project engineers must be ready to give up the detailed design work with which they are familiar and provide the flexibility, support, and oversight to others so they can ensure ultra-efficient performance is achieved and maintained over time.
Achieving smooth performance based design and operation of buildings is not a simple adjustment. It will take time and some experience to get the process right. But the fundamental change in the process must come from the project engineers themselves. Until it does, they [we] are the enemies of the change the building industry so desperately needs.
To hear Tom Hartman discuss Performance Based Building Design and Operations in greater detail, be sure to attend the Engineering Green Buildings conference in Las Vegas October 21-22 http://egbconference.com/
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