Page 168 - Zero Net Energy Case Study Buildings-Volume 3

ZERO NET ENERGY CASE STUDY BUILDINGS, VOL. 3 OBSERVATIONS
Observations
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Zero Net Energy Case Study Buildings: Volume 3
Volume 3 of Zero Net Energy Case Study Buildings examines the design and performance of six more major buildings located in the three principal population areas of California: the San Francisco Bay Area, the Los Angeles-San Diego metropolitan areas, and the Central Valley. The geographic expansion of the case studies reveals that ZNE design strategies can be uniformly applied in these areas, though with obvious adjustments for the duration of the heating and cool- ing seasons in the different climate zones.
These case studies are also, in some cases, somewhat different than those of the previous volumes—complex, large and part of a campus of buildings that are very much part of the story. They do not lead to the usual discussions of energy accounting for a single building with a sepa- rate solar PV system or, for that matter, of energy modeling versus energy performance. Never- theless, there are a number of observations that can be made of these case study buildings that have general application.
Building Metering and Monitoring Issues: Include in Design and Commissioning
For all of the projects in Volume 1 and several of the projects in Volume 2, the metering and energy monitoring systems essentially had to be commissioned and required post-occupancy adjustments to function properly. Some never delivered reliable data on building performance. Unfortunately, the same failing was experienced in several of the case study projects of Volume 3. The performance of these buildings could be ascertained only from the utility’s net meter alone. In one case, because the subject building was serviced for heating and cooling by an unmetered connection to a central plant, the energy consumption could only be estimated.
There is little question of the value of collecting reliable energy use and energy production data from the installed systems in a ZNE building. It allows energy monitoring and troubleshooting any observed anomalies in performance. Especially for “smart” buildings, which is the usual nature of effective ZNE designs, it is essential to have this monitoring in real time.
The issue appears to lie with the initial design of the metering system to deliver manageable, organized data as well as the thorough commissioning of these systems to ensure that the sys- tem is delivering the data as intended. After that, the building operator must have a program of regular monitoring, checking for accuracy and recording the data for evaluation. If any of these steps are missing, the data is lost and usually not retrievable.
Although proof of ZNE performance is not a requirement except for certification by the Interna- tional Living Future Institute (ILFI), a building client/owner usually welcomes accurate perfor- mance monitoring for this purpose.
Integrated Master Control Systems: Essential Design Role for “Smart” Buildings
The case study buildings of Volume 3 demonstrate continuing advance in the design of ZNE buildings, namely, the value of the master control system and the new corresponding design team role of systems integrator. This is discussed in some detail in the Introduction to Volume 2 and remains an ongoing issue with the design, commissioning and operation of high perfor- mance buildings.
Natural Ventilation for Fresh Air and Cooling: Maximize “Free Cooling” Potential
It is interesting to see the different approaches in the case studies of Volume 3 to the design strategy of natural ventilation. This remains one of the under-utilized design strategies for greatly reducing the cooling energy use in buildings, particularly in the marine climate zones of Califor- nia, which contain most of the major population centers of the state. The case study buildings employ the range of design approaches from simple occupant-operated windows with no integra- tion with building management systems to more sophisticated technologies using full integration.
The case studies provide valuable comparisons of these design approaches for different building