Selected Highlights of the Labs21 2007 Annual Conference

Action-Oriented Benchmarking for Laboratories

Pierre Bull, New York State Energy Research and Development Authority and Paul Mathew, Lawrence Berkeley National Laboratory

Abstract

A wide spectrum of laboratory owners ranging from universities to federal agencies have goals for energy efficiency in their facilities (e.g., the Energy Policy Act of 2005 for federal agencies). Laboratories, with their complex building systems and special health and safety requirements, are much more likely to meet energy efficiency goals if quantitative metrics (i.e., units of measure) and benchmarks (i.e., level of performance) are explicitly specified and tracked during the design of new buildings and the operation of existing buildings.

We introduce an action-oriented benchmarking protocol that can be used to specify and compute key energy efficiency metrics and benchmarks for laboratories. These metrics include the traditional whole-building energy use metrics (e.g., BTU/sf-yr), but more importantly, system-level metrics such as ventilation efficiency (W/cfm). The protocol is action-oriented in that it indicates how the metrics can be used to identify the presence or absence of energy efficiency features and opportunities. This protocol, which is being developed by the Lawrence Berkeley National Laboratory (LBNL) with funding from the New York State Energy Research and Development Authority (NYSERDA), builds on the Labs21 benchmarking tool as well as new developments in action-oriented benchmarking.

The primary target audience for the protocol is energy managers and commissioning agents, to help them track building and system efficiency and identify opportunities for efficiency improvement. When the protocol is fully developed, it will provide step-by-step guidance on how to collect data, compute metrics, and identify opportunities. Toward that end, the table below summarizes some of the key metrics, benchmarks for different levels of efficiency, and efficiency opportunities that the metrics can help identify.

Metric

Benchmarks

Application

Whole building energy intensity

1st Quartile in peer group (e.g. Site BTU/sf-yr from labs21 database)

Screening for overall efficiency potential

Ventilation

Minimum laboratory ventilation rate

6 ACH or 1cfm/sf

Optimize ventilation rate for safety and energy efficiency

Ventilation airflow efficiency (total supply + exhaust power/total supply + exhaust airflow)

Good practice: 0.6 W/cfm

Better practice: 0.3 W/cfm

Low pressure drop design, fan efficiency

Total system pressure drop (supply and exhaust)

Good practice: ~6.2 in. w.g.

Better practice: ~3.2 in. w.g.

Low pressure drop duct design, low pressure drop coils, filters

Fumehood airflow control ratio (average flow/minimum flow)

Good practice: 2

Better practice: 1.5

Variable air volume hood sash management

Fumehood density (hoods / unit lab area)

Varies; Compare to similar facilities

Optimize number of fumehoods; avoid excess fumehoods

Heating and Cooling

Note: Key metrics for chiller and boiler systems in laboratories are not different that those used in other commercial buildings - chiller efficiency (kW/ton), cooling load (tons/gsf), boiler efficiency (%), pumping efficiency (hp/gpm), etc. These are well-documented elsewhere (e.g. ASHRAE standards). Additional metrics important for laboratories are listed below.

Temperature and humidity setpoints in laboratories

ASHRAE 55 (for human comfort)

Avoid overly restrictive temp and humidity tolerances; isolate sensitive equipment

Chiller system minimum turndown ratio

Good practice: 10%

Better practice: 5%

Right-size chiller systems; optimize chiller plant operation for low part loads

Reheat energy use factor (ratio of reheat energy/total energy)

Best practice: 0% (no reheat)

Commission reheat controls; separate thermal and ventilation systems (e.g. use fan coils in labs)

Process loads

Design plug load intensity

Compare to measured plug load intensity

Right-size systems based on measured intensity.

Measured plug load intensity

Varies by lab function

Right-size systems based on measured intensity.

Lighting

Required illuminance level

Follow IESNA guidelines:

50 fc on horizontal surface

Optimize lighting levels; avoid over-lighting

Lighting power density

Good practice: 1.3 W/sf
(CA Title 24)

Efficient fixtures, lamps, ballasts

 

These metrics can also be used to evaluate the design of new laboratory buildings, and may be included in programming documents.

Finally, it is important to note that benchmarking is most effective when it is properly integrated into the business process for organizational energy management. Key considerations:

  • Prioritize metrics and set targets with stakeholder team. Metrics and targets are in effect key performance indicators for energy management, and therefore should have the buy-in of all the stakeholders.
  • Identify individual(s) responsible for tracking and reporting metrics.
  • Develop streamlined process and format for tracking and documenting metrics.
  • Incorporate key metrics and targets in decision-making processes for infrastructure investments.

View this entire presentation in PDF format (4.4 MB, 30 pp)

Biography

Paul Mathew is a staff scientist at Lawrence Berkeley National Laboratory, where he works on applied research in energy efficiency and environmental sustainability in the built environment. His current work is focused on energy efficiency and green design for laboratories and other high-performance buildings; energy benchmarking tools and techniques; and risk analysis of energy efficiency projects. He has a Bachelor degree in Architecture, and a Ph.D. in Building Performance and Diagnostics from Carnegie Mellon University. His work experience includes technical research, tool development, and teaching in energy efficiency, sustainable design, and risk management. Prior to joining Lawrence Berkeley National Laboratory, he worked at Enron Energy Services and the Center for Building Performance at Carnegie Mellon University.