Office / Conference / Classroom: “Top Five” Energy Efficiency Strategies by Building Type

“Offices”, “conference” spaces, and “classrooms” share a similar energy profile. Spaces in this group include rooms for one individual, up to small groups of as many as 50 people. Spaces are designed around human comfort and productivity, supporting individual work, group interaction, and collaborative learning. Energy use is generally driven by the needs of human comfort, minimum fresh air requirements, and mitigating the effects of climate, including extremes of temperature, solar heat gains, humidity, or environmental pollutants.

The most effective EEMs for Offices are those that reduce or eliminate environmental controls, such as natural ventilation, displacement ventilation, and demand control ventilation. Decoupling heating and cooling from ventilation is highly effective, especially when linked with demand control or natural ventilation. EEMs that target the building envelope, such as increased airtightness, increased building insulation, reduced glazing, triple glazing, or reduced thermal bridging are extremely important to overall energy use, since a tight building envelope can dramatically reduce mechanical systems demand. EEMs that target lighting efficiency are also highly effective.

Our “TOP FIVE” EEMs for Offices include (in rough relative order of impact on energy usage):

  1. Optimize Building Massing and Orientation
    • Use surrounding terrain and/or structures to shield the building from heat and/or wind effects
    • Orient building to minimize solar gains and (very important) glare effects from west facing window walls
    • Use narrow floorplans to maximize available natural light
    • Optimize height, width, and depth of building to minimize heat transfer through the envelope.
    • Allow adequate space for mechanical systems, avoiding “pinch points” that reduce mechanical systems efficiency
  2. Optimize Building Envelope
    • High R-value walls and roofs
    • <40% glazing
    • High performance glazing, including low SHGC, thermally broken curtainwall and windows, etc.
    • Obsessive detailing to avoid thermal bridging and maximize air tightness
  3. Natural Ventilation
    • Strategies vary from simple operable windows to complex mechanical dampers.
  4. Displacement Ventilation with Demand Control
    • Strategies include under floor air distribution (raised floors), low return / high supply ventilation (such as in auditoria and atria), and/or individual air supply diffusers integrated into furnishings.
    • Carbon Dioxide sensors are normally used for “demand control”, providing more fresh air distribution when levels of CO2 rise within a space. CO2 sensors and/or occupancy sensors can also be used as a means of initiating an “unoccupied” mode, where fresh air, temperature, and/or humidity control are relaxed, saving significant energy.
  5. Optimize Mechanical Equipment
    • Use high efficiency central plant resources if available (chilled water, steam, campus co-generation, etc)
    • High Efficiency boilers, chillers, cooling towers, etc.
    • Recirculated air system: most building air is “recirculated” within the building, rather than exhausted to the atmosphere. In normal operation, approximately 30% fresh outdoor air is mixed with recirculating air to reduce carbon dioxide levels, odors, and “stale” feeling.
    • Enthalpy wheel makeup air handling unit: high efficiency main distribution air handling unit with integral enthalpy (heat) wheel technology. Enthalpy (heat) wheels transfer waste heat and moisture from the outgoing exhaust air into the incoming supply air, reducing the need to condition incoming air, dramatically reducing energy use.
    • Airside economizer mode (unconditioned outdoor air is directly used or mixed with return air to reduce conditioning demand when outdoor temperatures are equal to makeup air design conditions).
  6. High Efficiency Lighting
    • Optimized lighting requirements, including reduced lighting standards (lowered footcandle levels). This is especially effective in corridors, mechanical spaces, and storage areas, where high intensity lighting may not be required.
    • High efficiency fluorescent lighting
    • Daylight Dimming: sensor controlled lighting that dims and/or turns off when sunlight entering a space is sufficiently bright for required lighting level.
    • Vacancy Sensing: sensor controlled lighting that turns off automatically when space is empty, but does not turn back on automatically (lights must be manually switched on by a person).
    • Low Ambient / Targeted Task lighting: room overhead lighting that is generally “dimmer” than normal, supplemented with high-efficiency “task” lighting, such as under counter lights, desk labs, and/or lab bench lighting.

 

 “GO BEYOND” STRATEGIES

  1. 100% continuous insulation at exterior walls (Structural Insulated Panel Systems – SIPS)
  2. Triple Glazing
  3. Automated sunshades
  4. External sunshades
  5. Geothermal Heat Pump
  6. LED Lighting

 

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