Page 169 - Zero Net Energy Case Study Buildings-Volume 3

ZERO NET ENERGY CASE STUDY BUILDINGS, VOL. 3 OBSERVATIONS
types and provide insights to the issue of maximizing the great free-cooling potential of natural ventilation (including the strategy of “night purging”) while providing the enhanced perception of thermal comfort via some occupant control.
It is clear from the case studies that a design strategy that uses solely occupant-control not only fails to take advantage of the large potential free-cooling available but can even result in counter- productive effects if not properly operated. Yet, this is the approach taken in three of the six case study buildings in this Volume 3. All three buildings are located in a marine climate zone where “night purging” could have been utilized for significant free cooling—a ZNE operation strategy not possible with only occupant-operated control of natural ventilation openings.
This is an evolving issue that will be affected by the introduction of new “smart” technologies, so- phisticated control systems and reliable hardware in the next few years. Likewise, now-available advances in energy modeling software, particularly incorporating current state-of-the-art compu- tational fluid dynamics (CFD), will build confidence among designers in predicting finely detailed air movement through buildings, making the design of automatic adjustment of openings part of the early design process.
Future ZNE case study buildings will no doubt incorporate these available technologies and demonstrate the great potential for free-cooling while at the same time providing occupants a sense of control of the thermal comfort conditions of their space. This is the ideal to strive for in these future designs.
Non-Technical Issues: The Need for User Training and Involvement
Early designs for ZNE buildings (see Volume 1) involved clients and users who embraced the role of “early adopters” of this then-novel approach to building design. The result was usually strong user involvement in the monitoring and operation of the building’s energy features. This active involvement in the everyday performance of the building supported the design intentions for the design features and their proper operation.
As ZNE buildings move more into the mainstream in the next few years and are operated and occupied by the “majority” of users, there is the design issue of selecting systems and features that do not require the intervention of these users to be effective. (See discussion above about the natural ventilation design strategy). There is also the intermediate condition that the selected systems, which may be non-conventional and unfamiliar to most users including maintenance staff, nevertheless require some simple training to ensure proper operation and even non-inter- ference by users that would be counter-productive to the operation of these systems.
The latter will be a particular design concern for K-12 schools, which is a building category that is emerging as a prime candidate for ZNE design before the target date of 2030, when the ZNE code requirement will likely be set. Case Study No. 13 in this Volume 3 is an example of such a project that devised a ZNE design for a portion of the project and this issue of user training emerged as a significant “lesson learned”. For a user population, including both occupants and maintenance staff, that is at best only casually interested in the ZNE performance of the building, the appropriate training is essential.
The observation from this case study is that the informational training must be a planned periodic event because of natural changes in the user population. It is critically important that this be on- going for the maintenance staff for the same reason and that the district facilities management bureaucracy accept this responsibility.
In general, this will be a common issue in the next decade of ZNE design of most building types. The common solution involves some degree of user training, which requires owner commitment to regular programs for staff and users, as well as the design team’s continued involvement in the post-occupancy period with the owner’s staff and commissioning agent.
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