Designing flexible, safe labs: Energy efficiency

Respondents:

• Jennifer DiMambro, CEng, MIMechE, MCIBSE, Principal/Americas Science, Industry & Technology Business Leader, Ove Arup & Partners, PC, New York City
• Adam Fry, PE, Project Manager, Associate, Mueller Associates Inc., Linthicum, Md.
• Paul Harry, PE, LEED AP, Senior Project Manager, Dewberry, Raleigh, N.C.
• Jared Machala, PE, LEED AP, Vice President, WSP, Houston

How has the demand for energy recovery technology influenced the design for these kinds of projects?

Paul Harry: A positive market trend is the increase in available technologies and competition among energy recovery types, including energy recovery wheels, air-to-air plate heat exchangers, heat pipes and wrap-around coils. This makes it easier for engineers to evaluate and provide them in the design of their projects. Nearly every lab project has some form of energy recovery included.

What level of performance are you being asked to achieve, such as WELL Building Standards, U.S. Green Building Council U.S. Green Building Council LEED certification, net zero energy, Passive House or other guidelines?

Jennifer DiMambro: We are seeing a range of performance levels requested by laboratory clients, most typically U.S. Green Building Council LEED where we are often targeting U.S. Green Building Council LEED Gold and starting to see more progressive clients looking at U.S. Green Building Council LEED Platinum. WELL is less typical in the science sector but I think will become increasingly important, particularly in life science development as developers look for new ways to differentiate their offer in the market. Net zero energy is a focus for many of our major clients, particularly those with large estates/campuses where we can look at holistic solutions across the campus rather than on a building-by-building basis.

A project in this sector that is a great example of employing sustainable design was the Interdisciplinary Science and Engineering Complex at Northeastern University. Our Boston team used BIM and parametric models to drive energy consumption down achieving a 33% energy cost saving over code (Massachusetts stretch code requires 20%).

Jared Machala: The most typical level of U.S. Green Building Council LEED we are being asked to design laboratories to is U.S. Green Building Council LEED Sliver. We currently have a laboratory under construction in Manhattan, Kansas, that has been successfully designed to U.S. Green Building Council LEED Silver status and a laboratory currently under design in Atlanta that has a U.S. Green Building Council LEED Silver goal.

Paul Harry: We are seeing many teaching/university lab buildings targeting a minimum of U.S. Green Building Council LEED Silver.

What types of renewable or alternative energy systems have you recently specified to provide power?

Paul Harry: We have applied solar photovoltaic on other project types, but have not seen its use in laboratory buildings, partly due to the constant or high number of operating hours with a steady demand for power and the high cost of battery storage systems. An owner may have difficulty justifying the first cost when it accounts for a smaller portion of the utility bill and with less “sell-back” hours than with other building types, such as schools or offices. Although, there are still energy savings to be realized during peak solar hours when the building is fully occupied and functional, given there is a good roof or ground location for the PV installation.

What types of sustainable features or concerns might you encounter for these buildings that you wouldn’t on other projects?

Jared Machala: We have recently designed two laboratory facilities on the same site that both harvested rainwater and cooling coil condensate. Cooling coil condensate is of particular interest because a large amount is generated by the typical 100% outside air requirement of laboratory facilities. After the water is collected it is routed to a common pond that is used for irrigation of the surrounding landscape. The pond is also a water feature for the site that increases the user experience for occupants of both facilities.

Paul Harry: Sustainable features include energy recovery for the high amount of 100% outside air required manifolded and variable volume exhaust systems.

Concerns include maintaining pressure control, as well as relative humidity control, during unoccupied or reduced occupancy setback schedules. Also, the use of energy recovery wheels, which have a very high effectiveness, is limited by the amount or risk of cross contamination between exhaust and supply air streams. They can be used, however, if carefully and properly engineered to suit the project.

Adam Fry: A major concern for lab buildings is contaminants from the exhaust airstream crossing over into the supply airstream when implementing airside energy recovery. Specifying total enthalpy wheels with good seals and adequate purge can limit crossover. But, depending on what hazards are being exhausted or perhaps the risk sensitivity of the client, other energy recovery methods may need to be incorporated that would otherwise not be used in a typical project.

What unusual systems or features are being requested to make such projects more energy efficient?

Jennifer DiMambro: Dynamic control is definitely an area that can have a dramatic impact on energy consumption. Intelligently controlling the ventilation rates based on actual conditions in the lab means that we can move away from constant high air change rates. Likewise, absence/presence detection on lighting and fume extract systems can have a significant impact. The other area to consider is better operational energy modelling — often models that meet code are not representative of the actual lab conditions and increasing client’s awareness of this and bringing in more detailed operational modelling at an early design stage can greatly assist in making design decisions that have a real impact.

Paul Harry: None that I would consider unusual, but more typical of other building types including maximizing equipment efficiencies, more daylighting, low-energy building envelopes and the use of energy recovery in the HVAC systems.

What value-add items are you adding these kinds of facilities to make the buildings perform at a higher and more efficient level?

Paul Harry: Every project is unique, so the challenge is to have an experienced (in laboratory building types), integrated team, not just the mechanical engineer, to develop the best performing as well as most efficient building for each specific project and owner.

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