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Dallas College

Ten Steps to Net Zero Energy

Existing Buildings

The suggestions below are not numbered because each existing building situation is unique; implement the suggestions in the order that meets the needs and goals of the organization.

Strive to reduce your overall Energy Use Intensity (EUI) to 20 to 25 KBTU/SF/year.

Roofs

  1. Increased Insulation - Satisfy currently adopted minimum code standards and seek to exceed standards as budget and implementation allow
    1. New R42 minimum composite rating with open or closed cell foam.
      1. Spray applied R42 minimum under decking
      2. Rigid closed cell foam or lightweight concrete above the roof decking.
  2. Evaluate the impacts on curbs/roof mounted devices on a case-by-case basis.
  3. New, high Solar Reflectivity Index (SRI) reflective roof membrane of 0.85 or higher.

Orientation Mitigation

  1. Mitigate existing solar orientation of glazing and building walls
    1. Motor-operated/sensor-controlled interior shading devices
    2. Green screens and/or Living Walls
      1. Utilize low maintenance/water demand plants
    3. Fixed exterior shading devices
    4. Landscaping e.g. strategic tree planting
    5. Films on windows
  2. Each solution will require a design solution specific to its location and requirements either by retaining a professional design team or enlisting the help of faculty/students.

Lighting Retrofit

  1. Evaluate lighting design and redesign on a cost-benefit basis. Consider formal evaluation and redesign if:
    1. Existing light levels far exceed IES standards or
    2. LED retrofit is anticipated to far exceed IES standards once implemented
  2. Update all lighting to LED fixtures.
    1. Eliminate all high wattage lighting, accent, safety, area, general and task.
  3. Targeted prioritization of areas/lighting types to maximize impact on consumption and demand savings is as follows:
    1. High Intensity Discharge (HID) exterior
    2. Halogen accents
    3. Common areas
    4. Office areas
    5. Classrooms
    6. Storage/Mechanical/Electrical/Elevator rooms

Lighting Controls

  1. Install multi-faceted controls
    1. Occupancy sensors
    2. Light harvesting sensors
    3. Occupancy schedules that match campus calendar and space use
    4. Sun controlled interior shading devices (should be biophilic patterned)
  2. Explore 5G LED lighting solutions that serve as routers to help solve WIFI issues in concrete buildings.

Energy Management Plan

  1. Building scheduling software
  2. Lighting controls
  3. High efficiency HVAC controls
    1. Consistent programmed set points
    2. Optimized sequence of operation for existing building management controls, equipment staging, OA control, pump control, economizer controls, CO2 integrated controls, exhaust fans, cooling towers
  4. Regular maintenance schedule
    1. Coil cleaning
    2. Filter change out and upgrades
    3. Commissioning checklists for PM work on equipment
  5. Implement Campus wide - six Core Strategies
    1. Best-in-class Campus and Equipment Scheduling
    2. Consistent Space Temperature Setpoints
    3. Equipment Staggered Start
    4. Equipment Capacity Control
    5. Proper Equipment Maintenance
    6. Building Automation Operation

Baseline Iterative Modeling, and Costing Evaluation Measures

  1. Develop comprehensive baseline modeling of all built inventory
    1. Extensive documentation of actual energy consumption - daily, seasonally, annually and over multiple years (benchmarking)
    2. Analyze the cost-effectiveness of different measures
    3. Update on an ongoing basis
  2. Employ energy modeling on a case-by-case basis. Modeling is useful in these kinds of cases:
    1. To analyze the cost-effectiveness of different measures
    2. Weigh the levelized costs between efficiency and renewables
  3. Continue to document campus wide impact from short-payback projects that may not have engineering support

HVAC System Wide Upgrades

  1. Upgrade or replacement of existing HVAC Systems
    1. Equipment replacement energy evaluations
      1. DX cooling for all 24/7 zones
      2. Eliminate pneumatic building controls
      3. VFD’s and controls on all pumps and fans larger than 5 hp
      4. High efficiency chillers and controls – possible addition of VFD’s to existing chillers
      5. High efficiency boilers and controls
      6. Evaluate the use of VRF systems and other emerging technologies, considering impact of installation, accessibility and serviceability of associated controls, and total lifecycle cost analysis
      7. Enhanced indoor air quality strategies
        1. Demand Controlled Ventilation
        2. Evaluation of UV treatment
        3. Evaluation of Bipolar ionization

Infiltration/Exfiltration

  1. Weatherization of building envelope
    1. Weather-stripping
    2. Sealants & caulking
    3. Thresholds, door sweeps, astragals
    4. Refurbish all aged and failing building sealants

Window & Glazing Replacement

  1. Where replacement is required of window and glazing systems due to system failure, replace with windows that have these minimum specifications
    1. Thermally-broken frames
    2. Insulated glazing
      1. U Value: ≤ 0.35
      2. SHGC: ≤ 0.30
    3. High performance glass – Southern Low E
  2. Utilize energy modeling to evaluate window retrofit/replacement options

Occupant Behavior

  1. Identify operational methodologies to maintain energy efficiency and optimal performance
    1. Create a collaborative implementation plan between occupants, users and facility managers
      1. Identify or appoint campus schedulers that understand building mechanical systems and impact of space management on energy use; develop HVAC zone maps to inform scheduling decisions
    2. Provide training for facility management staff
      1. Develop online training modules to assist in training/distribution on knowledge
    3. Identify plug loads and engage user groups and occupants on methods to reduce the loads
      1. Use Smart Strips for plug load management
    4. Create behavioral education programs and incentives to engage occupants and users
    5. Institute purchasing processes that mandate energy efficient key equipment and replacement cycles to upgrade for efficiency
      1. Purchase and distribution of low-wattage personal heaters; rely on policy and best practices to limit or eliminate other devices.

New Buildings

Strive to reduce your overall Energy Use Intensity (EUI) to 20 to 25 KBTU/SF.

Integrated Design

  1. Before the design phase is started, conduct design charettes with all key stakeholders to ensure that the energy efficiency goals are supported and achieved:
    • Owners
    • Administration
    • Staff (Facilities)
    • Architects
    • Engineers
    • Contractors and Sub-Contractors
  2. Follow green standards of choice (certification is optional)

Orientation

  1. Design buildings to respond to regional environmental criteria, e.g. passive solar design.
    1. Design building as close as feasible to an east / west long axis
    2. Orient large expanses of glazing to augment natural daylight strategies
      1. Eliminate or provide minimal glazing on the west elevations
    3. Green screens and/or Living Walls
      1. Utilize low maintenance/water demand plants
    4. Fixed exterior shading devices
    5. Landscaping e.g.:
      1. Strategic tree selection and planting
      2. Understory plantings to encourage cooling and hardscape mitigation
      3. Plan pathways, seating and public spaces to take advantage of plantscape and natural ventilation
    6. Design to maximize illumination of spaces with natural daylighting e.g.:
      1. North facing clerestories
      2. Architectural light shelves
      3. Skylights
      4. Daylit corridors and large atrium public spaces adjacent to glass walls and/or transom lights (windows?)

Baseline Iterative Modeling, and Costing Evaluation Measures

  1. Develop comprehensive baseline modeling
    1. Project energy consumption - daily, seasonally, annually and over multiple years
    2. Analyze the cost-effectiveness of different measures
    3. Update on an ongoing basis
  2. Employ energy modeling is useful to:
    1. Analyze the cost-effectiveness of different measures
    2. Weigh the levelized costs between efficiency and renewables
  3. Comply with IECC 2018 at a minimum
    1. If possible, achieve the following distribution:
      1. HVAC: 0.90 w/SF (~50% of load)
      2. Lighting: 0.35 w/SF (~20% of load)
      3. Plug Load: 0.55 w/SF (~30% of load) – Use advanced power strips to reduce load
    2. Weigh the levelized costs between efficiency and renewables

Roofs

  1. Insulation
    1. All insulation shall be R42 minimum composite rating with open or closed cell foam.
      1. Spray applied R42 minimum open cell or closed cell under decking
      2. Rigid closed cell foam or lightweight concrete above the roof decking.
  2. New high Solar Reflectivity Index (SRI) reflective roof membrane
    1. 0.95 or higher.
  3. Consider implementing Living Roof designs
  4. Incorporate PV Solar arrays

HVAC Systems

  1. Upgrade proposed HVAC Systems to highest efficiency that is cost effective
    1. Equipment energy evaluations
      1. DX cooling for all 24/7 zones
      2. VFD’s and controls on all pumps and fans larger than 5 hp
      3. High efficiency chillers and controls – possible addition of VFD’s to existing chillers
      4. High efficiency boilers and controls
      5. Evaluate the use of VRF systems
      6. Enhanced indoor air quality strategies, e.g. increased CFM rates, UV filtration
  2. Design air distribution systems utilizing displacement ventilation
  3. Incorporate operable windows and natural ventilation to the greatest extent possible
  4. Utilize stack effect ventilation

Windows & Glazing Systems

  1. Window and glazing systems shall meet these minimum specifications
    1. Thermally-broken frames
    2. Insulated glazing
      1. U Value: ≤ 0.35
      2. SHGC: ≤ 0.30
    3. High performance glass – Southern Low E
  2. Utilize energy modeling to evaluate high performance glazing options

Lighting

  1. All lighting shall be LED fixtures.
    1. Eliminate all high wattage lighting, accent, safety, area, general and task. Note: Add standard watts per square foot to Building Standards

Lighting Controls

  1. Install multi-faceted controls
    1. Occupancy sensors
    2. Light harvesting sensors
    3. Occupancy schedules that match campus calendar and space use
    4. Sun controlled interior shading devices (should be biophilic-patterned)
  2. Explore 5G LED lighting solutions that serve as routers to help solve WIFI issues in concrete buildings.

Energy Management

  1. Building scheduling software
  2. Lighting controls
  3. High efficiency HVAC controls
    1. Consistent programmed set points
    2. Optimized sequence of operation for existing building management controls, equipment staging, OA control, pump control, economizer controls, CO2 integrated controls, exhaust fans, cooling towers
  4. Regular maintenance schedule
    1. Coil cleaning
    2. Filter change out and upgrades
    3. Commissioning checklists for PM work on equipment
    ​