Page 84 - Zero Net Energy Case Study Buildings-Volume 1

CASE STUDY NO. 4
WATSONVILLE WATER RESOURCES CENTER
Energy Design Analysis and Energy Performance -
Modeling versus Initial Post-Occupancy Measurements
Energy Use – Modeling
The energy modeling for the Water Resources Center was carried out using eQuest version 3.51. All of the final design strategies described above were incorporated into the final energy analysis, including a typical pattern of use for the occupant-operated natural ventilation and the gas-fired high-efficiency boilers for radiant slab heating.
The model shows a predicted energy use of 267 MWhr and an EUI of 56.9 kBtu/sq. ft. per year, including energy from both gas and electric sources. The dominant energy use is expected to be plug load, with heating on the office wing and the cooling primarily in the laboratory wing of the building.
See the summary of the modeling results on the facing page. Note that the EUI for this mixed- function laboratory/office building is in the range of 50-60, which is generally double what is considered a good design benchmark for the annual energy use of a basic office building in this climate. However, laboratories have a much higher energy demand per unit floor area; buildings that include some laboratory space have a much higher EUI than simple office space.
Since one of the criteria for a good ZNE design is a low EUI as compared with other buildings of a similar type, the Watsonville WRC was benchmarked against other recently-completed mixed- function laboratory buildings in the same climate zone, with similar laboratory functions and similar size, and with a comparably small fraction of the building area given over to laboratory space. That is, the laboratory space in the benchmarking comparison is only a minor fraction of the total building area.
The benchmarking was done using the Labs21 benchmarking tool1 and the results are shown in the figure below. As the benchmarking exercise shows. the Watsonville Water Resources Center has an exceptionally low EUI, as desired in a model ZNE case study building.
1 http://labs21benchmarking.lbl.gov/
EUI
Average EUI for Peer Buildings
EUI for Watsonville WRC
(Right) Chart of benchmark EUIs for comparable project types. (Edward Dean)
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Zero Net Energy Case Study Buildings: Volume 1