Page 57 - Designing for Zero Carbon - Case Studies of All-Electric Buildings

MAKERS QUARTER BLOCK D OFFICE BUILDING
CASE STUDY NO. 2
Energy Design Analysis and Energy Performance:
Modeling versus Post-Occupancy Measurements
Energy Use — Modeling
Energy modeling was carried out during the design phase using Integrated Environmental Solu- tions Virtual Environment (IESVE) software to run parametric studies of various design features and their effect on energy use. Energy Pro was used for Title-24 compliance and the Savings by Design program.
The energy model was done for a fully leased (fully occupied) building since the systems were being designed for such a case. Designing for natural ventilation and daylighting, with optimized sun control in the benign climate of San Diego, results in extraordinarily low energy use by the HVAC systems. This can be seen in the summary pie chart of the modeled annual energy use by category of load (heating, cooling, lighting and equipment) on the following page.
The effect of this mild climate on the modeled monthly energy use, shown in the bar chart on page 45, is to produce an energy use profile that is fairly constant throughout the year, with a modeled EUI less than 30.
Energy Use — Actual Measurement and Comparison to Modeling Results
The building was completed and partially occupied in December 2018. A major tenant moved into three upper floors in August 2019, bringing the building to virtually full occupancy. A few months afterward, the pandemic shutdown occurred, which distorted the actual energy use pat- terns of the building. The measurement of the energy performance, which is recorded for the one single year of normal occupancy (2019), is skewed by the period of partial occupancy in the first eight months of the year.
The annual energy use for the entire year is half that of the modeled fully-occupied building, as can be seen in the chart at right. Note that the recorded data only differentiates between the core-and-shell spaces (the “Common Area”) and the leasable spaces (the “Tenant Area”). As can be seen in the chart of the measured monthly energy use on p. 44, the energy use increases by a factor of almost four when the building goes to full occupancy. A simple calculation of the EUI assuming a monthly energy use equal to that of the last months of 2019 yields a value of approximately 22, which is less than the modeled EUI of 29.2.
Measurement data for one year of post pandemic occupancy is required for full evaluation, but it appears that the actual building energy performance is easily better than that modeled.
Designing for Zero Carbon: Volume 1
43