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Going Green: How Primus Is Working with United States Cold Storage & Unilever to Achieve LEED Silver Certification

December 2, 2014
Author: Rebecca Elliott

As a member of the U.S. Green Building Council, Primus Builders is committed to finding ways for Owners to incorporate sustainable design and construction features into their projects. The firm’s current project with United States Cold Storage (USCS), a 315,000 SF dedicated frozen food distribution facility located adjacent to an existing 815,000 SF production facility, is its latest effort to achieve Owner-requested LEED certification goals.

The new facility will be “plant-attached” to a building currently operated by Unilever. Unilever is internationally recognized for its firm commitment to conducting business as a good steward of the environment. This is evidenced by its implementation of the Unilever Sustainable Living Plan (USLP), a program that reduces Unilever’s environmental impact while increasing its positive social impact. On this project, Unilever has set a goal of LEED Silver certification.

Primus initiated conversations about sustainability options immediately upon project award. This set the tone for sustainability to be incorporated into the overall project approach, not just as an agenda item during the commissioning process. The LEED scorecard was studied, and only points that would maximize USCS and Unilever’s return on investment were selected.

Primus’s dedicated sustainability manager, William Taylor, LEED AP, is working alongside the project team to achieve the Owner’s established LEED goal. “A minimum of 50 points is required to achieve LEED Silver. Currently, we are on track to achieve 55. We build in a cushion, just in case there are any challenges with the scoring. We are confident we will achieve USCS and Unilever’s sustainability goal.”

LEED points are being achieved in areas like sustainable sites, water efficiencies, materials and resources, indoor environmental quality, energy and atmosphere and innovation and design. The most challenging area to earn points is the one with the biggest process energy load: refrigeration. Primus is earning LEED points in refrigeration by implementing the following measures:

Freezer and Corridor Evaporator Fan Upgrades

Primus will install evaporators with a lower fan horsepower to capacity ratio and control evaporator speed with variable frequency drives (VFDs). This will save energy by reducing the motor power and the refrigeration load contribution from the evaporator fan motors.

Booster Compressor VFD

Primus will install a VFD on the reciprocating booster compressor. This will save energy by improving part load compressor efficiency.

High Stage Compressor VFD

Primus upgraded the compressor oil cooling from liquid injection to glycol. Glycol oil cooling increases compressor capacity and reduces compressor shaft power requirements. It also requires a condensing pressure of only 90 psig compared to liquid oil cooling, which requires 120 psig. Primus will also install a VFD on the high stage screw compressor to improve the efficiency of the part load compressor.

Oversized Condenser

Primus will install oversized condensers with a higher MBH/horsepower ratio. Like the evaporators described above, this action will increase energy efficiency by reducing motor power.

Condenser Fan VFDs

Primus will install VFDs to control condenser fan speed. VFDs require fewer mechanical components and vary their output speed based on need.

LED Lighting (Refrigeration Savings)

Primus will upgrade the baseline lighting to LED lighting with motion sensors. This will increase light efficiency and reduce power.

These measures and others are expected to reduce refrigeration energy consumption by 32%.

This project is one of Primus’s most exciting LEED projects to date. To ensure it is completed accurately and to the Owners’ exact specifications, Primus will implement an enhanced commissioning process. All LEED components will be tested for accuracy and the USCS and Unilever teams will receive specific training to operate the equipment effectively.

Unilever and USCS are not alone in their willingness to push for sustainability in the cold storage industry. Owners from across the country have expressed similar interests in making their facilities more eco-friendly. Primus sees the advantage sustainable design and construction offers its clients and is eager to assist with these endeavors.