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Design Guidance

Overall Strategies

The HVAC (Heating, Ventilation, and Air Conditioning) system is the greatest use of energy within the workplace. HVAC systems are most efficient when run at full capacity, making it critical to choose a system that correctly fits the needs of the building. Reduce cooling and heating loads through implementing efficiency strategies such as: installing efficient insulation, preventing air leakage, installing energy efficient windows, and reducing solar gain (e.g. cool roofing and window tints). HVAC systems facilitate the exchange of air to the outside as well as circulation of air within the building, controlling the temperature, removing moisture and contaminates, and distributing fresh air. The mechanical system must be efficient, durable, and sized properly. Prior to occupancy, perform building commissioning. Learn more: Whole Building Systems.

Thermostat

A thermostat is a component of the HVAC controls system. Detection and communication of the space temperature is a critical component of overall HVAC controls. Most new thermostat controls are DDC. Older pneumatic systems can be upgraded to DDC for better control. Zone control is critical.

Sound boots

Sound-boots are integrated into the duct-work between the office walls in the ceiling. The duct work is often shaped like a boot. If properly specified and installed, the sound boot will help control the transfer of sound from one area to another.

Sound Masking

Electronic sound masking systems can be installed in office areas. A sound masking system generates "white noise" that helps mask other sounds. Sound masking systems help make an open office area more functional for the occupants.

Kitchen Exhaust Hoods

Kitchen exhaust hoods are a large energy consumer in cafeteria spaces. Significant amounts of energy can be conserved by utilizing transfer air – conditioned air from adjacent spaces – as replacement air, thus reducing the need for conditioned makeup air. Fan energy can also be saved by reducing air circulation when cooking activity is low. Demand ventilation systems (DVS) conserve energy by vary exhaust and makeup fan speeds in alignment with the demand of existing conditions. ANSI/ASHRAE/IES Standard 90.1 sets energy efficiency requirements for kitchen exhaust hoods.

Green Tips

  • Install occupant control thermostats that have prescribed temperature range limits to promote occupant comfort.
  • Ensure the air supplied by the HVAC system is properly conditioned - providing comfortable temperature ranges, removing moisture and air contaminants such as odors, dust, and carbon dioxide. Proximity to an exterior wall should be evaluated to minimize ductwork.
  • Ensure the minimum level, or higher, of outside air is circulated within occupied spaces to increase indoor air quality.
  • Use thermostats with occupancy sensors to reduce energy consumption.
  • Use filtration media to removing moisture and air contaminants such as odors, dust, and carbon dioxide.
  • Use underfloor air distribution for reconfigurable technology ready space as power, voice, and data services are easily accessible with access floors.
  • Install IT load meters to track consumption of the computer equipment as a separate item from HVAC or base-building load.
  • Planned in advance and separately zone HVAC in the corridor and set temperatures to conserve energy.
  • Separately zone HVAC in rooms with copy machines to help protect IAQ. Copier equipment gives off a lot of heat when in use, so supplemental air supply may be required.
  • For smaller data rooms consider use of exhaust fans and grills in place of CRAC units.
  • For larger data centers use hot/cold isle strategies to maximize HVAC system performance.
  • Use and maintain supplemental exhaust vents to effectively ventilate restrooms.
  • Consider using carbon dioxide sensors to regulate the circulation of outside air while the enclosed conference room is occupied to increase indoor air quality and save energy.
  • Design HVAC systems to have multiple zones, specifically near south and west facing facades to increase thermal comfort in areas with more severe temperature swings.
  • Conserve energy by using transfer air--conditioned air from adjacent spaces--in order to minimize the need for conditioned makeup air.
  • Design for high efficiency kitchen hoods with low capture and containment (C&C) airflow rates. Ensure air exchange rates are maintained above code minimums, including NFPA 96 and local restrictions, but below ANSI/ASHRAE/IES Standard 90.1-2010 recommended maximums.
  • Consider automating kitchen exhaust via temperature, smoke, or appliance energy use sensors to optimize performance.
  • Utilize demand control ventilation (DCV) kitchen hoods to conserve energy by reducing exhaust airflow when cooking is not taking place. ASHRAE provides guidance for DCV testing and configuration.
  • Consider heat recovery options to extract heat from kitchen exhaust to reheat ventilation air or service hot water.
  • Evaluate whether chilled beams would meet your laboratory’s cooling needs better than a variable air volume system. Chilled beams not only allow for efficient and even cooling but also minimize air blowing down on lab benches and disturbing scientists' work.
  • Design or retrofit existing labs with energy recovery systems. These may include devices that recover energy from exhaust air, such as enthalpy wheels, heat pipes, or run-around loops.
  • Design ventilation based on real or virtual laboratory models that simulate airflow patterns and optimize ventilation rates under different scenarios (e.g. a spill).
  • Specify low-pressure-drop design for each component of the air distribution system, including air handler coils, energy recovery devices, VAV control devices, zone temperature control devices, ductwork, and exhaust stacks.
  • Consolidate equipment that generates a lot of heat away in an equipment room or away from air supply to manage impact on laboratory cooling needs. Locate exhaust registers above the back of hot equipment to remove it before it recirculates into the room.
  • Control and group substances according to air change rate needs. For example, optimize airflows to do work only up to a certain control band or designate specific hoods for work with certain substances.
  • Provide options to easily increase ventilation in an emergency with an override button.
  • Tailor ventilation to specific tasks and to small labs within a suite, which are equipped with local exhaust (e.g. biosafety cabinet). Some recirculated air workspaces may be appropriate next to 100% exhaust rooms.
  • Design process water cooling into equipment rooms. Water cooled freezers may enable chilled beam cooling of equipment rooms. Be sure to have backup water flow in case of power outage.
  • Exhaust snorkels can be useful in limited applications to remove localized heat or nontoxic particles. They should always have a damper that can be closed off when not in use. Install as few as possible to meet current lab needs. Ducts can be stubbed through the ceiling and closed off to facilitate future snorkel installation if needed.

Compare HVAC Options

EB = Existing BuildingsNC = New Construction and Major Renovation

Federal Requirements

Guiding Principles

  • Energy Efficiency ( Guiding Principles, Executive Order <span>13693</span> [NC])
    Section: II. Optimize Energy Performance

    From the Guiding Principles for NC: “Employ strategies that minimize energy usage. Focus on reducing energy loads before considering renewable or clean and alternative energy sources. Use energy efficient products as required by statute.”
    Determining Compliance: “For new construction, ensure energy efficiency is 30% better than the current ASHRAE 90.1 standard. For modernization, ensure: (1) energy use is 20% below the fiscal year (FY) 2015 energy use Baseline, (2) energy use is 30% below the FY 2003 energy use baseline, (3) the building has an ENERGY STAR® rating of 75 or higher, or (4) for building types not in ENERGY STAR Portfolio Manager, where adequate benchmarking data exists, the building is in the top quartile of energy performance for its building type. For new construction and modernization, use energy efficient products, as required by statute.”

  • Energy Efficiency ( Guiding Principles, Executive Order <span>13693</span> [EB])
    Section: II. Optimize Energy Performance

    From the Guiding Principles for EB: “Employ strategies that minimize energy usage. Focus on reducing energy loads before considering renewable or clean and alternative energy sources. Use energy efficient products as required by statute.”
    Determining Compliance: “Ensure: (1) the building has an ENERGY STAR rating of 75 or higher, (2) energy use is 20% below the FY 2015 energy use baseline, (3) energy use is 30% below the FY 2003 energy use baseline, or (4) energy efficiency is 30% better than the current ASHRAE 90.1 standard. Use energy efficient products, as required by statute.”

  • Commissioning ( Guiding Principles, Executive Order 13693 [EB])
    Section: I. Employ Integrated Assessment, Operation, and Management/Design Principles

    From the Guiding Principles for EB: "Meet the commissioning requirements of Energy Independence and Security Act (EISA) of 2007 section 432 and Federal Energy Management Program (FEMP) guidance. Employ recommissioning, tailored to the size and complexity of the building and its system components, in order to optimize and verify performance of building systems. Recommissioning should be led by an experienced commissioning agent who is independent of the facility operations team. Building recommissioning should include a commissioning plan, verification of the performance of systems being commissioned, and a commissioning report that confirms identified issues were appropriately addressed."
    Determining Compliance: "Commissioning reports for certification purposes must be completed within two years prior to certification date. Recommissioning should be completed at least every four years thereafter to optimize building performance. Use commissioning agents who are independent of the design and construction or operating team. Commissioning should be consistent with EISA section 4327 and FEMP commissioning guidance."

    DOE EERE - Commissioning for Federal Facilities
    DOE - Guidance for the Implementation and Follow-up of Identified Energy and Water Efficiency Measures in Covered Facilities.

  • Ventilation and Thermal Comfort ( Guiding Principles, Executive Order <span>13693</span>&nbsp;[EB, NC])
    Section: IV. Enhance Indoor Environmental Quality

    Guiding Principles for NC & EB: “Provide safe and healthy ventilation and thermal comfort.”
    Determining Compliance: “Meet the current ASHRAE 55 and either 62.1 or 62.2 standards for ventilation and thermal comfort.”

  • Commissioning ( Guiding Principles, Executive Order <span>13693</span> [NC])
    Section: Section: I. Employ Integrated Design Principles

    From the Guiding Principles for NC: "Employ commissioning tailored to the size and complexity of the building and its system components in order to optimize and verify performance of building systems. Commissioning should be led by an experienced commissioning provider who is independent of the project design and construction team and the operations team. At a minimum, commissioning should include a commissioning plan, verification of the installation and performance of systems being commissioned, and a commissioning report that confirms identified issues were appropriately addressed. Follow Energy Independence and Security Act (EISA) of 2007 section 432 and associated Federal Energy Management Program (FEMP) commissioning guidance.”
    Determining Compliance: “Commission and recommission at least every 4 years to optimize building performance using commissioning agents who are independent of the design and construction or operating team. Commissioning should be consistent with EISA section 4321 and FEMP commissioning guidance.”

    DOE EERE - Commissioning for Federal Facilities
    DOE - Guidance for the Implementation and Follow-up of Identified Energy and Water Efficiency Measures in Covered Facilities