Designers take a hands-on approach to building operations

John Jennings

Some people like to design and build things, while others like to fix things. These preferences converge in the world of commercial buildings, where the building designer hands off to the building owner, who then turns the responsibility for operating performance over to facility managers, building operators and maintenance contractors. Then, more often than not, operating performance is generally evaluated on the basis of operating costs.

The defined project roles of architects and engineers emphasize their design responsibilities. In an integrated design process, the role of commissioning has become more important to help ensure that designs are effectively translated into operating performance. Today, the commissioning agent usually has one foot in the design camp and the other in operations.

Efforts to increase the overall performance of buildings—energy consumption, environmental footprint, interior environmental quality—have generated a much more comprehensive set of performance criteria and a reassessment of roles, responsibilities and membership on the project team. Integrated design frameworks are being implemented to generate innovative solutions to meet higher performance targets. Project teams are expanding to include more occupant representatives and are inviting earlier participation from consultants and subcontractors.

Yet investigations of building performance repeatedly leads to the conclusion that there are significant differences between designed energy performance and actual energy performance.

It turns out that it is extremely hard to predict the actual energy performance of buildings. The tools used by designers to analyze energy performance are, at best, able to analyze the relative performance of different designs under a certain set of conditions. The final building may perform exactly as designed, relative to the characteristics that designers control. However, there are many other conditions that affect building operation and energy performance that are not under the purview of the design team.

Assumptions made during design about building operating schedules can only approximate actual use. There are unavoidable weather differences between the average year used for energy modeling purposes and any actual year of occupancy. The number of occupants in the building, estimated during design, fluctuates with changing business conditions. And occupant equipment loads—a growing percentage of total building energy use—evolve with occupant need and technological change and are usually greater than what is input to the model.