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50 California is located in the heart of San Francisco's Central Business District
Shorenstein Building Management Team

Showcase Project: 50 California Street

Sector Type

Commercial

Location

San Francisco, California

Project Size

735,000 Square Feet

Financial Overview

Total Investment: $465,000

*Energy costs are normalized and calculated using 2015 electricity rates

Annual Energy Use

Baseline (2008)
170 kBtu/sq ft
Actual (2015)
118 kBtu/sq ft

Energy Savings:

31%

Annual Energy Cost

Baseline (2008)
$2,119,000*
Actual (2015)
$1,496,000

Cost Savings:

$623,000
Background

50 California Street was designed by architect Welton Becket & Associates in 1971. The building’s facade features vertical precast concrete columns with black spandrel and grey light glass panels. 50 California occupies a strategic location in the heart of San Francisco’s Central Business District, at the junction of California and Davis Streets.

Shorenstein Realty Services completed a multi-year project to convert the building control system from pneumatic to direct digital control (DDC). The additional accuracy and control of DDC permits energy efficiency opportunities as well as better responsiveness to ventilation and conditioning needs throughout the building. In addition to the building control system upgrade, the team completed a number of energy efficiency measures that together have contributed to a 31 percent reduction in annual energy use since 2008.

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Shorenstein continuously evaluates and improves the sustainability of the company’s investment and management practices. The company’s operating platform provides a blueprint for property management teams to manage building environmental impacts effectively. Shorenstein believes sustainability is not only the right thing to do, but a sound and valuable business practice.

Building on this philosophy and operating platform, the 50 California property management and engineering team developed a compelling business case for delivering energy savings and occupant comfort via DDC. The team demonstrated their ability to complete the project and successfully gained senior management and ownership support for the project.

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Solutions

Converting a large building such as 50 California Street from pneumatic to DDC is a complex and expensive undertaking that must be planned and executed carefully. The feasibility of DDC conversion depends on multiple factors including existing equipment, the skillsets of staff members, and financial means.

The replacement of the original pneumatic system was phased in over several years, starting with installation of the DDC “backbone” infrastructure and followed by conversion of the floor controls in tenant suites throughout the building. The engineering team played a central role in planning, design, and implementation of the DDC conversion project. The team also received operator training from the controls manufacturer to ensure proficiency in use and maintenance of the new system.

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In December 2014, the engineering team leveraged the power of the new DDC system to implement an innovative, energy-saving ventilation control strategy. The team developed a control algorithm to independently adjust the speed of 68 supply air fans throughout the building based on duct static pressure. Known as the Static Pressure “Hot Button” by the engineering team, this digital control strategy has reduced electricity cost by $96,000 annually while ensuring optimal ventilation on each floor throughout the building.

In total, Shorenstein has invested more than $465,000 in energy efficiency measures since 2008:

  • Installed a new DDC system at the central plant and a DDC system for 68 fan rooms, including automatic return air reset and critical zone reset.
  • Modified 68 floor fan static pressure setpoints to reduce fan motor energy use.
  • Installed a differential pressure sensor at 7th floor, 10 2-way valves on heat pumps, and a variable frequency drive (VFD) on tenant cooling tower pumps.
  • Installed a VFD on each of three elevator machine room fans, to be controlled by the DDC system.
  • Installed VFDs and differential pressure sensors to enhance boiler hot water pump control and reset schedule.
  • As part of tenant improvements, installed LEDs and DDC controls on 15 floors, totaling 270,000 sq ft.
  • Replaced 1,250 T8 fluorescent fixtures with LEDs.
  • Replaced 89 150-watt PAR38s with 19-watt LEDs, 35 75-watt PAR38s with 16-watt CFLs, and 17 60-watt PAR38s with 16 watt CFLs in ground floor retail space. Utility incentive of $4,000 resulting in no project cost for the building or tenant.
  • Replaced 187 20-watt MR11s with Sylvania 2.2-watt LEDs in 18 elevator cabs.
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Other Benefits

Shorenstein began benchmarking in EPA ENERGY STAR Portfolio Manager® in 2007, which provided a mechanism to track energy performance and identify potential upgrades. Since beginning to benchmark, the building has maintained continuous ENERGY STAR certification and the building’s ENERGY STAR score has improved from 84 to 96, meaning the building is now more efficient than 96 percent of all office buildings.

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In 2015, the property management and engineering team at 50 California Street won the San Francisco Building Owners and Managers Association (BOMA) “Innovative Earth Award."

In September 2016, Shorenstein announced the LEED Platinum recertification of 50 California Street, demonstrating outstanding operational performance exceeding the original LEED Gold certification earned in 2011.

Shorenstein Realty Services has used the 50 California example as a model for the conversion of other building control systems to DDC. Shorenstein expects other buildings to achieve similar efficiency outcomes as 50 California Street in the future.

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