One of the important activities in Phase 1 was to identify major O&M problems in commercial buildings. We assumed a broad definition of the concept of an O&M problem: an O&M issue that caused an increase in energy use beyond the expected performance of a building system. For example, a cooling tower that operates when the chillers are off causes unnecessary energy use. The expected performance is for the tower schedule to be coordinated with the chiller schedule, but such problems are common in commercial buildings.

Our initial plan was to develop a list of the major classes of O&M problems along with their severity and frequency. This plan had to be modified due to the broad nature of O&M problems found in commercial buildings, as further discussed below. The two primary sources of information use in this task were: review of published literature and analysis of existing case study data, and interviews with building engineers and operators, and industry O&M workshops. The review of published literature included evaluating conference proceedings and journal articles discussing the relationship between O&M and energy use in commercial buildings. Research results from demonstration projects and programs such as Texas A&M University's LoanSTAR program (Haberl et al, 1996), PG&E's Advanced Customer Technology Test (Hernandez and Brohard, 1994), Bonneville Power Administration's Energy Edge Program (Piette et al, 1994), and Pacificorp's Energy FinAnswer Commissioning program (Piette et al., 1996, Yoder and Kaplan, 1992) were considered.

The literature review suggests that virtually all buildings have some sort of O&M problem, and the vast majority of buildings are not carefully commissioned. Previous published case studies indicated that careful review of hourly end-use and whole-building energy performance data can result in savings equivalent to about 15 percent of annual operating costs (Herzog and Lavine, 1992, and Claridge et al, 1994). These savings are much greater (up to 40 percent) in some cases.

The second source of information we drew upon was the results of detailed, personal in-depth interviews and feedback from building owners and operators. These interviews were based on an extensive, 50-page, questionnaire designed to tabulate O&M problems and characterize building owners' and operators' experiences with diagnostic and control technologies. The questionnaire contained detailed sections asking about commissioning practices, organization of maintenance activities, the use of preventative maintenance diagnostic technologies (e.g., vibration analysis, thermography, etc.), Energy Management and Control System (EMCS) sensor maintenance and calibration. The research team toured fifteen facilities to obtain first-hand experience with current control technologies and the way operators interact with them.

The on-site interviews were based on an O&M questionnaire designed to structure information collected from building personnel. The idea was to identify their most important problems in O&M, after which we would tabulate and focus on the most common ones. Instead of generating these kinds of seemingly straightforward results, the underlying problem turned out to be much more complex. We expected, but did not generate a list of common specific problems for which we could generate a clean set of diagnostics. The difficulty with identifying all common O&M problems is that reports of these problems tend to be anecdotal rather than statistically significant. Instead of identifying a detailed set problems, we found a more critical and diverse set of structural problems that need to be addressed by any successful diagnostic approach.

The key problem we identified is that building operators lack good information on major building systems we identified is that the information tools currently in use in these buildings severely limit a building managers' ability to assess their own O&M practices in a comprehensive manner. As mentioned, the questionnaire had sections asking about continuous information systems such as EMCSs, as well as one-time and short-term diagnostics such as vibration analysis and thermography. The most significant conclusion from the surveys and literature search is that building managers have little information on the energy performance of their major building systems, such as the cooling plant, lighting, and ventilation. They therefore have very limited capabilities to:

• detect and diagnose problems or
• evaluate the economic benefit of modifying O&M practices or changing existing equipment with more efficient equipment.

The general problem of lack of information on major building systems comprises a series of specific problems. For example, the most sophisticated building managers reported problems in keeping sensors properly calibrated. Thus, the information directly available from the EMCS is questionable. Temperature, humidity, and flow sensors were all reported as problematic, with the most concern over humidity and flow sensors. The following five constraints were also found to be significant in evaluating opportunities for a continuous diagnostic system.

• Constraint 1: Black Box Technical Complexity Confuses Operations - Class A building engineers want to understand how their control and diagnostic systems operate. For a variety of reasons, current advanced control systems often fail in this regard. Many control systems use proprietary, black-box control algorithms. It therefore is difficult for operators to assess the impact of changes in control strategies. There is a significant challenge to the buildings industry to integrate operators and sophisticated systems in order to provide optimal results. Clear feedback to an operator on how the technology functions is essential but frequently nonexistent in current systems.
• Constraint 2: Economic Constraints Limit Innovation - Building managers operate in a tight economic environment. Investments in building systems must have defensible estimates of energy and cost savings. These investments must ultimately lower tenant costs and have a quick payback. New or retrofitted systems that do not produce expected savings can seriously jeopardize one's career. Diagnostic systems must provide defensible cost-benefit information in a usable form if investments in improved O&M or retrofits are to be approved.
• Constraint 3: Energy Cost Reduction is not a Top Priority - Building managers compare the annual energy use and costs of individual buildings with others for which they have data. These data may be from their own portfolio, from trade association statistics, or from utility data. Most building managers do not seek aggressive reductions in annual energy use and associated energy costs provided that their building is not dramatically far from other benchmark data. Rather, building managers and engineers spend significant time responding to complaints and seeking to maintain high standards of comfort and indoor air quality. Similarly, preventative maintenance is of great interest. A diagnostic system that assists in these areas as part of the effort to reduce energy costs is desirable.
• Constraint 4: Lack of Knowledge of Information Technology Limits Innovation -Building managers are interested in strategies to improve the energy performance of their buildings, but lack the training in new information tools needed to conceptualize and evaluate the next level of building efficiency technologies. The computer facilities available to them are limited.
• Constraint 5: Poor Initial Designs Cause Ongoing Problems - The most common problem reported by the managers was that critical equipment was often poorly (either under or over) sized. The second most common problem reported was that some aspect of the equipment layout was faulty. These managers see these problems as continual issues in achieving optimal operations. They currently have no formal mechanism to document these problems, economically justify retrofits or provide feedback to designers, which might help ensure that the problems are not repeated in the future.

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