Page 75 - Designing for Zero Carbon-Volume 2_Case Studies of All-Electric Multifamily Residential Buildings

VERA CRUZ VILLAGE
CASE STUDY NO. 3
The Phase 1 energy modeling was separately done for the apartments and the community build- ings, which would also receive similar standard energy retrofit measures (R-38 roof attic insula- tion, double-glazed windows and replacing all gas space heating and DHW systems with electric heat pump systems). The Phase 1 energy modeling results for the apartments only are shown in the chart below.
The Phase 2 energy modeling studied Building 619, which was retrofitted with the “demonstra- tion” measures, and one of the 41 “other” buildings that received the conventional retrofit mea- sures in Phase 3.
Building 619, consisting of four apartment units, was modeled with the envelope features de- scribed in the earlier sections, including the insulated metal panel system for the roofs and ordinary double-pane windows. A highly-efficient heat pump equipped with an Energy Recovery Ventilator (ERV) to capture energy from the exhaust air stream was modeled as well. The model- ing results for this building in Phase 2 are shown in the charts on the next page (p. 62).
This energy modeling analysis shows that Building 619 would improve its annual energy per- formance from an estimated EUI of 49.9 to an improved EUI of 18.4 (kBtu/sf per year). The improvement would be greatest in the energy consumed for heating and DHW, while eliminating the entire use of natural gas for those purposes.
The “Other” building, consisting of three apartment units, was modeled with the conventional retrofit features to meet California’s Title-24 code requirements, which included double-pane win- dows and R-30 roof insulation. The heat pump installed for heating and cooling was a standard rooftop packaged unit (COP=3.6).
(Below) Location of the two buildings selected for the Phase 2 energy modeling of the special retrofit measures applied to the Demonstration Buildings versus the standard retrofit measures applied to the other 41 apartment buildings.
“Other” Building
“Demonstration” Building 619
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