Page 144 - Zero Net Energy Case Study Buildings-Volume 2

ZERO NET ENERGY CASE STUDY BUILDINGS, VOL. 2 OBSERVATIONS
Observations
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Zero Net Energy Case Study Buildings: Volume 2
The case study buildings documented and discussed in this Volume 2 represent a certain ad- vance in understanding of the design strategies and building technologies that produce the best performance results for ZNE buildings. This has come about as a result of communication of the results and experience with early ZNE buildings as well as the appearance of new technologies that have been recently developed to improve operation and general performance. At the end of Volume 1 of Zero Net Energy Case Study Buildings, the section on Observations took note of some common issues with the early ZNE building projects documented there. It’s interesting to compare those observations with similar aspects of the case study buildings in Volume 2, con- firming the advance in understanding and resolution of some of those issues.
Energy Modeling versus Actual Performance
Generally, the same observations apply about whole building energy modeling being used to set energy performance targets or predict results—there are limitations and design professionals cannot guarantee a certain level of performance during the first years of occupancy. Compar- ing the energy modeling results with the measured performance for the buildings in Volume 2, the actual energy use tracks the modeling data well, with some expected variation due to the drought-year weather and clear skies experienced by most of these buildings when the full-year measurements were done.
Building Metering and Monitoring Issues
For all of the projects in Volume 1, the metering and energy monitoring systems essentially had to be commissioned and required post-occupancy adjustments to function properly. For the two projects where the accuracy of the metering system was in fact tested by comparing its results with the utility meter, the building metering system had to be overhauled to ensure reliable results going forward.
While this assessment of the quality of the data being recorded is still required, the case study buildings in Volume 2 that incorporated a master control system were also connected to an on- line dashboard for easy energy data reporting and review. Extracting and communicating data from the different building systems is relatively straightforward when the metering/monitoring system is part of the overall integrated controls and communication system. Given the impor- tance of making energy use data “actionable” in order to optimize building performance, the installation of a master control system, as demonstrated by several of the case study buildings, facilitates this purpose.
Integrated Master Control Systems
The case study buildings of Volume 2 demonstrate at least one significant advance in the design of ZNE buildings, namely, the value of the master control system and the new corresponding de- sign team role of systems integrator. This is discussed in some detail in the Introduction, as well as in each of the case studies. Suffice it to say that this particular new development in building technology and systems design will become part of the best practices for design of ZNE build- ings.