Page 73 - Zero Net Energy Case Study Buildings-Volume 3

LA ESCUELITA EDUCATION CENTER
CASE STUDY NO. 13
Post Occupancy: Observations and Conclusions
This large and complex K-12 project is ambitious in its energy performance goals and “cutting edge” in some of the design strategies employed. The project succeeded in achieving a very low energy use, as evidenced by its EUI, and installed a sizable solar PV system on available rooftops. It also effectively created a model for the District of a design approach for energy performance that can be emulated in other District projects.
Like all new design approaches, there are inevitably degrees of success for different systems and impacts on the customary patterns of use and building maintenance. A candid assessment of these permits improved design in future projects and some of these are discussed below.
Post Occupancy: Controls and Monitoring
Control systems and metering of actual energy use continue to be a source of problems for many high-performance buildings. In this case, problems occurred with the metering system and the handoff to the data display company (Lucid) that was developing the on-site dashboard for reporting on energy use and energy production.
At the time that the system was initially commissioned, some of the metering circuit may have been incorrectly wired and this was not detected. In addition, some of the circuits were given unclear name assignments that were not descriptively clear about the energy loads being monitored. (The dashboard programmers could only use the information provided by the control system vendor and these were not vetted by District facilities staff.)
There were additional post-occupancy factors affecting the reporting of energy data on the part of the District. The on-site energy dashboard screen that displayed the metered performance was removed because the young students did not understand its purpose and used it as a me- dia toy. The online dashboard remained, intended as a method of regularly reporting the energy performance to District facilities staff. But due to personnel turnover, the District staff did not check the accuracy of the data being reported nor did they regularly monitor the performance of the different systems. The current District staff only became aware of the original issue of the metering system structure when asked to provide the energy use data for this case study. After considerable discussion among District staff, the dashboard technician and the project design engineers, the problems were identified and “work-arounds” were devised, as described in the section, Energy Use — Actual Measurement of Performance Results.
For future data reporting and monitoring, the District plans to investigate the metering system and correct any errors, effectively re-commissioning the system. An action plan will then be put in place for regular reporting on the energy performance of all features of the complex. This will enable the District to be aware of any anomalies in system functions and to investigate them.
Post Occupancy: HVAC
The “Cool Tower” represents a unique feature of the HVAC that is used in lieu of conventional mechanical cooling systems typically employed in K-12 projects. Its prototype design and performance was obviously not well known before construction, but as the data shows, the performance during the initial occupancy period has been good. Initially, the only operational issue was with the large damper banks common in evaporative coolers, which had to be engineered carefully so that they all closed at the same time.
The classrooms also functioned well with the displacement ventilation system and the thermal mass added to the classroom walls. Temperature sensors that were located in the floors showed that the night ventilation mode of operation was very effective. In fact, measurements indicate
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