CBECC-Com: California Building Energy Code Compliance (for COMmercial/Nonresidential buildings) software

CBECC-Com (California Building Energy Code Compliance) is an open source project that may be used by Code Agencies, Rating Authorities, or Utility Programs in the development of energy codes, standards, or efficiency programs. Architects, engineers, and energy consultants may also use these tools to demonstrate compliance with energy codes or beyond-code programs.

The software's key components are:

  • Graphical User Interface (GUI) - allows users to enter details about a proposed building's design
  • Ruleset - a computer-processable form of the building energy code
  • Compliance Manager - the core of CBECC. Uses the ruleset to assess whether the building complies with the energy code.
  • Connection to the U.S. Department of Energy's EnergyPlus Simulation Engine - performs energy simulations to compare proposed building energy consumption to the energy code "budget"
  • Report Generator - generates forms and other reports to summarize the building's compliance characteristics. Forms may be submitted for building permits, or as documentation for other programs.

CBECC-Com Version will include a Ruleset for California's 2013 Title 24 Energy Code. The Title 24 Ruleset represents the performance approach for compliance as described in the 2013 Nonresidential Alternative Calculation Method (NACM) Reference Manual. It will also feature an API to allow third party software developers to utilize the functionality of the CBECC-Com Compliance Manager.

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CBECC-Com Features

The goal for the CBECC-Com project is to implement all of the features in the NACM Reference Manual. However, the initial release will be focused on including the requirements necessary for it to be a certified by the CA Energy Commission. The minimum requirement for certification is that software must be able to generate an appropriate standard design model for a given user model. Additionally, it must be able to accurately model a large enough fraction of the new commercial construction in the state to be useful for those interested or needing to know how new building designs will perform in the energy efficiency context as compared to the 2013 Standards.

The following lists these minimum requirements:

Scope
  1. Newly constructed buildings
  2. Addition/Alterations and Partial Compliance
  3. CBECC-Com will produce results of the performance tests described in the 2013 Nonresidential ACM Reference Manual. Documentation is available on the Reference Method page.
  4. The 2013 Standards ruleset and rules processing software will have the capability to be included in third party compliance software using Dynamic Linked Libraries (DLLs) and will include ruleset encryption to “lock” the 2013 Standards ruleset.
Site/Building
  1. Include identifying information
  2. Include other general information required for compliance forms
  3. Include location information
  4. Identify climate zone and weather/design day files
Envelope
  1. Provide a comprehensive list of accurately described opaque materials
  2. Combine materials into constructions
  3. Describe fenestration performance properties via the simplified approach (U-value, SHGC, VT)
  4. Provide constructions which meet the u-value requirements by climate zone of opaque surfaces
  5. Provide glazing units which meet climate zone requirements for skylights and vertical glazing
  6. Apply exterior insulated constructions to demising surfaces
  7. Check that proposed exterior constructions meet mandatory u-value requirements
  8. Remove user model building shades
  9. Retain user model geometry
  10. Adjust excess user model fenestration to standard design maximum WWR and SRR values
Lighting and Other Internal Loads
  1. Replace user lighting systems with simple LPD values based on space function
  2. Allow simple lighting inputs for Lighting Power Density (LPD) and lighting schedules without the need to specify details of an interior lighting system
  3. Allow detailed lighting inputs for credits and allowances:
    1. Lighting Controls and associated PAFs
    2. Area Category Lighting Allowances
    3. Tailored Lighting Allowances
  4. Replace user occupancy and equipment loads with ACM specified values
  5. Replace user specified infiltration rates with ACM values
  6. Replace user specified schedules with ACM schedules
  7. Combine space level data into zones
HVAC
  1. Replace user specified HVAC system with baseline system
    1. Except data center, laboratory, kitchens
    2. Baseline sizing run is autosized
    3. Baseline run hard sized using baseline sizing results
  2. Model user specified HVAC systems with user-supplied sizing:
    1. PSZ
    2. SZVAV
    3. PVAV
    4. VAV
    5. PTAC
    6. PTHP
    7. Fan-coil units (4 pipe)
    8. Baseboard heating
    9. Heating coils
      1. Gas furnace
      2. Hot water
      3. Electric
      4. DX (heat pump)
    10. Cooling Coils
      1. Chilled water
      2. DX
    11. Boilers
      1. Hot water
      2. Gas
      3. Oil
      4. Electric
      5. Natural draft
      6. Mechanical draft
    12. Chillers
      1. Screw
      2. Reciprocating
      3. Centrifugal
      4. Air-cooled
      5. Water-cooled
    13. Chilled water loop pumping
      1. Primary only
      2. Primary-secondary
    14. Economizers
      1. Non-integrated
      2. Integrated
    15. Economizer Controls
      1. Fixed temperature
      2. Differential temperature
      3. Fixed enthalpy
      4. Differential enthalpy
Domestic Water Heating
  1. Storage water heaters
    1. Gas
    2. Electric
    3. Oil

    For all nonres building occupancies other than High-Rise Multi-family and Hotel/Motel, there are NO prescriptive service water heating requirements. This means that there are only mandatory service water heating requirements for most nonresidential buildings, and mandatory requirements cannot be traded off in the performance compliance approach.

Output
  1. Report simulation errors and warnings including useful descriptions
  2. Report number of hours with setpoint not met by thermal zone
  3. Report energy consumption by fuel and end-use
  4. Report TDV energy by end use
  5. Report TDV energy comparison of Proposed and Standard Design, including Compliance Margin
  6. Generate “NRCC-PRF-01” summary compliance form
  7. Generate Standard Design report for any Proposed Design
Interface
  1. Ability to access and modify parameters needed to simulate the above
  2. Option to perform simulations in two modes:
    1. Proposed Only (applies rules and simulates the Proposed Design)
    2. Proposed and Standard (applies rules and simulates the Proposed and Standard Designs)
  3. CBECC-Com QuickStart Guide available from “Help” tab
  4. CBECC-Com User's Manual available from "Help" tab
  5. CBECC-Com software license available from “Help” tab
Documentation
  1. Nonresidential ACM Reference Manual
  2. EnergyPlus Technical Documentation
  3. Meeting criteria in 2013 Nonresidential ACM Approval Manual (e.g. CBECC-Com Users Manual)
  4. Issues Log available with each CBECC-Com version release – to document bugs identified and fixed