High Efficiency Central Chiller
The high efficiency low temperature air distribution system generated cost savings in the form of a reduction in the overall size of fan systems and ductwork. The system’s bulk production capacity and heightened efficiency will also garner substantial operational savings throughout the building’s lifetime. More specifically, modeling results indicate that the combination of the central chiller plant, variable flow chilled water, wider deadband setpoints in common areas, night flushing, and low temperature air distribution create the capacity for the building to save 535,249 kWh per year compared to a baseline code-compliant building.
These savings account for 56% of the building’s total potential energy savings based on the installed energy conservation measures. Assuming a rate of $.07/kwh, the building will reap $37,450 in annual energy cost savings. Furthermore, these energy conservation measures eliminate roughly 535,000 pounds of carbon dioxide emissions per year, which is equal to the amount of carbon dioxide emitted from 1,486 car tanks of gas.
The integration of daylighting, daylight dimming controls, and improved glazing will yield 417,230 kWhin annual energy savings compared to a baseline code-compliant building. This integrated lighting design strategy accounts for 44% of building’s total annual energy savings and is projected to produce $29,200 in annual energy cost savings based on $.07 kWh energy rates. It also eliminates over 417,000 pounds of annual carbon dioxide emissions, which is equal to the amount of carbon dioxide emitted by over 1,158 car tanks of gas.
Ecoroof & Manhole Filtration System
Rainwater slowly infiltrates the ecoroof and is gradually released to the City’s storm/sewer system instead of running off all at once. This reduces the building’s potential contribution to combined sewer overflows, which result in the dumping of raw sewage into the Willamette River. The remaining water will be used via vegetative uptake and evaporation. The total amount of water handled by the ecoroof annually is approximately 320,400 gallons based on 36" average annual rainfall in Portland.
The "downstream defender" will earn the project the LEED stormwater treatment credit and has removal efficiencies of 90% for sediments and 30% for phosphates.
Block 4 earned a 3:1 FAR bonus for covering the building’s podium (setback) with an ecoroof and a 40:1 FAR bonus for installing bike storage, shower, and locker facilities in the garage. Both strategies also earn LEED credits for urban heat island reduction and alternative transportation. A restrictive covenant preserving a neighboring historic armory allowed the transfer of that site’s development rights to the other buildings on the property. In the end, the ecoroof, bike accommodations, and historic preservation enabled the developer to add three floors to the building’s tower (an extra 45’ in height).
Buildings with ecoroofs may also receive a stormwater fee reduction from the City in the near future.
Total annual output of the photovoltaic system is expected to be 21,600 kWh. This "free" energy will yield $1,500 in annual energy savings assuming an energy rate of $.07/kwh.
Block 4 anticipates earning a LEED Silver rating.
State of Oregon’s Office of Energy Sustainable Building Program: $223,755 LEED Silver (or $312,495 LEED Gold) in BETC tax credits
PGE's EarthAdvantage Program: funded energy modeling
Northwest Energy Efficiency Alliance: funded development of tenant manual and funding construction waste management coordination
City of Portland, Office of Sustainable Development’s G/Rated Program: funding for LEED certification
Energy Trust of Oregon: PV panel funding, also currently assisting with funding an interactive kiosk in lobby
Bonneville Environmental Foundation: partner in PV project