Significantly Reducing Energy Use in Existing Labs

The extent to which a lab is or isn’t energy efficient can be traced back to how the lab was designed and constructed. What can be done in existing labs, then, after the concrete’s been poured and design alterations aren’t feasible?

Believe it or not, the greatest potential for energy savings is in existing labs, not ones about to be constructed. This is because, generally speaking, existing labs are incredibly energy inefficient.

Cornerstone’s work at an Ivy League college proved just that. Our team was hired to commission a deep energy retrofit on an 85,000-square foot chemistry building constructed in the 90’s. It happened to be the most energy-intensive building on the campus, using about 960 KBtu per square foot. Cornerstone was involved from the early design phase to well after project completion.

The building used almost 100% outside air and there was no heat recovery. Each hood and each lab exhaust had its own individual exhaust fan, which meant a total 140 individual exhaust fans. Each of those individual fans used VFDs that were growing old and unreliable. On top of that, the mechanical penthouse was a mess from the rats-nest of ductwork and fans.

Among the many issues this building faced were:

  • High-hazard, hood-intensive labs
  • Poor airflow control, resulting in safety concerns
  • Poor exhaust dispersion
  • No heat recovery
  • Single-stage steam absorption chiller plant, which was inefficient and carbon intensive
  • No redundancy on critical lab exhaust systems

Part of the early work on this project involved making a case as to why this retrofit was necessary. Key stakeholders had to be convinced of the campus wide benefits; energy use and carbon emissions had to be benchmarked, and strategies developed to address both energy and operational deficiencies.

Once the project was approved, the scope of work entailed:

  • Removing 140 individual exhaust fans from the manifold lab exhaust system, and replacing them with six exhaust fans – 35,000-cfm each
  • Installing a new high efficiency glycol run-around system (manufactured by Konvekta)
  • Removing steam preheat coils in AHU’s and replacing with Konvekta coils
  • Replacing the single vane-axial supply fans with dual plenum fans
  • Replacing two 550-ton absorption chillers with two 850-ton high efficiency elective chillers, interconnected with the main campus chiller plant
  • Replacing / retrofitting fume hoods to improve capture and reduce airflow
  • Replacing / upgrading the lab airflow control system and building automation system
  • Balancing and re-commissioning all HVAC systems

The energy-saving results of this deep retrofit were impressive:

  • Anticipated first year energy savings: $248,000
  • Carbon emission reductions
    • 1,100 MTCDE / year (4% of campus target)
  • Estimated maintenance cost reductions
    • $50,000 / year
    • Increasing @ 5% / year
  • Peak demand reductions
    • Heating: 10,500 Mbtuh ($1,050,000 @ $100 / Mbtuh)
    • Cooling: 90 Tons ($420,000 @ $3,500 / ton)
  • ROI: 24.8%, plus improved reliability, environmental conditions, public image.

This project had a notable impact on the campus, with results that translated to a 12% reduction in fuel oil use for the entire institution.

To-date, it remains a highly talked about – and celebrated – project.

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