Part 2: Energy consumption and case studies
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Fig. 1. Energy profile of a typical life science lab building. All images courtesy of Ellenzweig.
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Closer scrutiny of the typical energy consumption of a life science research lab in the
northeastern United States reveals that the thermal loads are almost equal to all the other loads
combined (lighting, plug loads, air handling unit/fan energy, cooling and heating distribution)
(Fig. 1) Variations on this energy profile may be developed based on the laboratory type; for
example, an intensive chemistry building will likely have proportionally increased HVAC loads, and
increased overall energy usage given the larger quantity of fume hoods.
Consider the estimated annual energy use of a life science research lab in the northeastern
U.S., as shown in Table 1.
Life science lab energy
use
Table 1. Estimated annual energy use of a life science research lab in the northeastern
U.S. Source: Ellenzweig |
| Loads |
KBtuh/ft2/year |
GJ/m2/year |
| Thermal |
193 |
2.19 |
| Lighting |
32 |
0.36 |
| Plug loads |
73 |
0.83 |
| AHU/fan energy |
58 |
0.66 |
| Cooling |
44 |
0.50 |
| Heating distribution |
4 |
0.05 |
| Total |
404 |
4.54 |
What specific strategies can be adopted to effectively conserve energy?
Anecdotally, we can draw a parallel between buildings and human beings—both living systems—and
put our buildings on a “healthy diet.” Simply put, they need to:
- Consume fewer calories.
- Reduce weight: be diligent in not over-sizing the engineering systems.
- Reduce system pressure: static (air systems) and hydraulic.
- Balance “awake” and “sleep” time: turn off/turn down systems.
- Expose the building to the sun: natural light, solar energy, solar shading.
Looking at the energy profile in Fig. 1, effective strategies fall into the categories noted
below. The associated pie charts offer a visual representation of the amount of energy typically
consumed by these loads in a lab building.
Thermal loads
Since the thermal loads constitute 30 to 40% of the total energy loads of a typical research
facility, the largest impact in energy consumption reduction is potentially in revising the basis
of design of this category. For example:
- Reducing the airflow and design ventilation rates (less outside air).
- Providing dedicated cooling systems such as recirculating fan-coil units for high-load spaces
such as equipment and freezer rooms.
- Installing energy recovery devices to preheat/pre-cool air.
- Eliminating reheat with the provision of chilled beams and/or sidewall displacement.
- Improving the building thermal performance (i.e. building envelope).
With these strategies, the aggregate potential for thermal load reduction is in the order of 25
to 55% of the thermal loads of the building.(Insert Figure 2).
Electrical/lighting loads
The lighting loads of a research facility constitute 2 to 7.5% of the total energy loads.
Improving the lighting design, whether by daylighting or electrical lighting, will also contribute
to energy consumption reduction. (Insert Fig 3) Strategies include:
- Extending the impact of daylighting with the use of light shelves at the building
perimeter.
- Improving lighting efficiency with the use of compact fluorescent and light-emitting diode
(LED) light fixtures.
- Providing task lighting (equipped with occupancy/PIR sensors) and reducing ambient lighting
levels.
- Designing the building controls for automatic daylight sensing/dimming light fixtures and
occupancy sensors in all parts of the building.
Air handling unit (AHU) and fan energy loads
The AHU and fan energy loads of a research facility constitute 5 to10% of the total energy loads.
(Insert Fig 4). Energy conservation strategies include:
- Reducing the airflow rates by lowering the number of air changes in the lab, providing
low-flow fume hoods (at 60 to 80 fpm face velocity), demand-based controls and integrating chilled
beams wherever possible.
- Reducing system pressure losses with the provision of low-velocity ductwork (1,000 fpm),
low-velocity AHUs (400 fpm coils, filters) and low-pressure-drop variable air volume (VAV) boxes
/valves (0.3-in. wg).
Energy recovery devices
Energy recovery devices can contribute 20 to 25% to the thermal and chiller load reduction.
However, they vary in effectiveness, 
advantages and drawbacks, the most effective being the energy
(enthalpy) wheel. (Insert Fig 5). Energy conservation strategies include integrating one or more
of the following:
- Energy wheel (70% effective). Provides sensible and latent heat recovery; a safety bypass is
needed in case of cross-contamination.
- Glycol run-around loop (40% effective). Can be remotely located from the air handlers;
maintenance includes periodic disposal and recharging of glycol.
- Air to air heat exchanger (45% effective).
- Heat pipe (50% effective). Affords heating and cooling recovery; convenient side-by-side
design.
Chilled water and cooling system strategies
Improved chilled water and cooling systems constitute 2 to 5% of the total. (Insert Fig 6) Energy
conservation strategies include:
- Improving chiller performance (.52 kW/ton) with variable-speed operation.
- Selection of low-energy cooling towers with reduced fan horsepower and variable speed
operation.
- Use of a high-temperature differential system (16°F).
- Reduce flow rate/pump horsepower.
- Variable flow/variable speed pumping.
- Use of low-pressure-drop piping/fittings system by designing for 1 ft/100 ft loss.
In summary, the new paradigm for achieving sensible energy savings and effectively reducing the
global impact of energy use relies on four simple principles: reducing demand, increasing
efficiency, harvesting free energy, and recycling waste energy. Furthermore, whenever possible,
institutions that are well -endowed with a stock of existing buildings may be well-served to
consider more closely the option of adaptive reuse as a viable alternative to new
construction.
In this year of 2010, the majority of institutions continue to separate the budgets of
facilities—whether renovated or new—between capital and operating ones. With the rising cost of
energy and the imperative to reduce their carbon footprint, institutions will need to more closely
link the performance of their buildings over time with their initial investment. The day will come
when a seven-year ceiling on payback will no longer be the applicable norm, and capital and
operating budgets will inexorably be linked to the larger concept of achieving net zero
energy.
Four case studies attached to this article show how these energy-saving measures have taken
shape in real projects including the:
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology,
Cambridge
- Secchia Center, College of Human Medicine, Michigan State Univ., Grand Rapids
- Hach Hall, chemistry research facility, Iowa State Univ., Ames
- Amistad Research Building, Yale Univ. School of Medicine, New Haven, Conn.
Steve Mahler, AIA, LEED AP, is a principal and Shirine Boulos Anderson, AIA,LEED AP, is an
associate principal at Ellenzweig, Cambridge, Mass. (www.ellenzweig.com). The firm provides master
planning, programming, feasibility study, in-house lab planning and architectural design services
to academic, institutional and corporate clients. Allan Ames, PE, is a principal at BR+A
Consulting Engineers LLC, a Boston-based firm (www.brplusa.com). The company provides
mechanical/HVAC, electrical, plumbing and fire protection engineering services, as well as
building commissioning.
Published in Laboratory Design newsletter: Vol. 15, No. 10, October, 2010
