by Donna A. DeFreitas
Incorporating energy efficiency, renewable energy, and sustainable design features into all building designs has become a top priority for building owners, facilities managers, architects, designers, and others in new buildings. As states and local jurisdictions increasingly move toward more efficient building codes in regards to energy use, how can you guarantee that the design of your project will be a high-performance building design? Is it the building energy model developed in design? Why doesn’t my expensive building management system (BMS) do it for me?
The high-performance building design process begins when the occupants’ needs are assessed and a project budget is established. The proposed building is carefully sited, and its programmed spaces are arranged to reduce energy use for heating, cooling, and lighting elements. Its heating and cooling loads are minimized by designing standard building envelope elements like the roof, windows, and walls, so that they control, collect, and store the sun’s energy to optimum advantage. And the building systems are chosen to meet the end users’ program elements with regards to efficient design element requirements, environment conditions, and building occupancy.
High-performance building design is not just the result of applying one or more isolated building system technologies, but an integrated whole-building process that requires guidance, recommendations, and action on the part of the design team throughout the entire project development process, utilizing good design practices for planning and developing design approaches that encourage the achievement of complex building challenges. There is no official, legally recognized definition of good design practices, but its application involves a design process that is dynamic, repeatable, with involvement of the project’s end users and invested parties.
A notable observation on design from Steve Jobs, founder of Apple, is as follows: “Design is a funny word. Some people think design means how it looks [and feels]. But, of course, if you dig deeper, it is really how it works.”
How do we predict how a building design will work? Energy modeling is based on a series of assumptions about building characteristics that are based on physical attributes and anticipated use patterns. In my opinion, there are three hurdles to why a design phase building energy model does not accurately predict the actual building’s energy use. They are:
- The weather.
- Building operations.
- Building maintenance.
The weather is, well, the weather, but the building is only as efficient as how its facilities personnel operates it and how it will be maintained over the building’s life cycle. Building energy models need to be aligned with the actual building performance outcome in order for this design tool to effectively serve the design community in delivering high-performance building designs. Reducing excessive energy costs requires a comprehensive approach toward the low-energy building design and a dedicated facilities team to understand the design intent and effectively manage and review the operation after the building is occupied.
And what about that expensive BMS black box? Today’s advanced building designs and their sequence of operation can be complex and, therefore, confusing to operate. Ensuring your contracting partners understand the building design and how you want to operate your building are the first steps towards operating your building efficiently and lowering your building operational energy use. Your facilities operational personnel will also need to be trained to effectively manage the BMS.
When the building systems are designed, installed, and commissioned properly, the end result will provide a smart building that learns the building operations, produces the accurate ventilation levels, reduces energy consumption, and provides an optimal environment for the building occupants. Post-occupancy reviews and continuous commissioning standard operation procedures will assist in ensuring that your new building maintains its low-energy building design and life-cycle costs. The resultant energy savings from your high-performance building design will continue to grow year over year.
Donna DeFreitas
Donna A. DeFreitas is an associate principal at Vanderweil Engineers.
